WorldWideScience

Sample records for caustic stress corrosion

  1. Stress corrosion cracking of duplex stainless steels in caustic solutions

    Science.gov (United States)

    Bhattacharya, Ananya

    Duplex stainless steels (DSS) with roughly equal amount of austenite and ferrite phases are being used in industries such as petrochemical, nuclear, pulp and paper mills, de-salination plants, marine environments, and others. However, many DSS grades have been reported to undergo corrosion and stress corrosion cracking in some aggressive environments such as chlorides and sulfide-containing caustic solutions. Although stress corrosion cracking of duplex stainless steels in chloride solution has been investigated and well documented in the literature but the SCC mechanisms for DSS in caustic solutions were not known. Microstructural changes during fabrication processes affect the overall SCC susceptibility of these steels in caustic solutions. Other environmental factors, like pH of the solution, temperature, and resulting electrochemical potential also influence the SCC susceptibility of duplex stainless steels. In this study, the role of material and environmental parameters on corrosion and stress corrosion cracking of duplex stainless steels in caustic solutions were investigated. Changes in the DSS microstructure by different annealing and aging treatments were characterized in terms of changes in the ratio of austenite and ferrite phases, phase morphology and intermetallic precipitation using optical micrography, SEM, EDS, XRD, nano-indentation and microhardness methods. These samples were then tested for general and localized corrosion susceptibility and SCC to understand the underlying mechanisms of crack initiation and propagation in DSS in the above-mentioned environments. Results showed that the austenite phase in the DSS is more susceptible to crack initiation and propagation in caustic solutions, which is different from that in the low pH chloride environment where the ferrite phase is the more susceptible phase. This study also showed that microstructural changes in duplex stainless steels due to different heat treatments could affect their SCC

  2. Electrochemical studies on stress corrosion cracking of incoloy-800 in caustic solution. Part II: Precracking samples

    Directory of Open Access Journals (Sweden)

    Dinu Alice

    2006-01-01

    Full Text Available Stress corrosion cracking (SCC in a caustic medium may affect the secondary circuit tubing of a CANDU NPP cooled with river water, due to an accidental formation of a concentrated alkaline environment in the areas with restricted circulation, as a result of a leakage of cooling water from the condenser. To evaluate the susceptibility of Incoloy-800 (used to manufacture steam generator tubes for CANDU NPP to SCC, some accelerated corrosion tests were conducted in an alkaline solution (10% NaOH, pH = 13. These experiments were performed at ambient temperature and 85 °C. We used the potentiodynamic method and the potentiostatic method, simultaneously monitoring the variation of the open circuit potential during a time period (E corr/time curve. The C-ring method was used to stress the samples. In order to create stress concentrations, mechanical precracks with a depth of 100 or 250 μm were made on the outer side of the C-rings. Experimental results showed that the stressed samples were more susceptible to SCC than the unstressed samples whereas the increase in temperature and crack depth lead to an increase in SCC susceptibility. Incipient micro cracks of a depth of 30 μm were detected in the area of the highest peak of the mechanical precrack.

  3. POTENTIAL FOR STRESS CORROSION CRACKING OF A537 CARBON STEEL NUCLEAR WASTE TANKS CONTAINING HIGHLY CAUSTIC SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Lam, P.; Stripling, C.; Fisher, D.; Elder, J.

    2010-04-26

    The evaporator recycle streams of nuclear waste tanks may contain waste in a chemistry and temperature regime that exceeds the current corrosion control program, which imposes temperature limits to mitigate caustic stress corrosion cracking (CSCC). A review of the recent service history found that two of these A537 carbon steel tanks were operated in highly concentrated hydroxide solution at high temperature. Visual inspections, experimental testing, and a review of the tank service history have shown that CSCC has occurred in uncooled/un-stress relieved tanks of similar construction. Therefore, it appears that the efficacy of stress relief of welding residual stress is the primary corrosion-limiting mechanism. The objective of this experimental program is to test A537 carbon steel small scale welded U-bend specimens and large welded plates (30.48 x 30.38 x 2.54 cm) in a caustic solution with upper bound chemistry (12 M hydroxide and 1 M each of nitrate, nitrite, and aluminate) and temperature (125 C). These conditions simulate worst-case situations in these nuclear waste tanks. Both as-welded and stress-relieved specimens have been tested. No evidence of stress corrosion cracking was found in the U-bend specimens after 21 days of testing. The large plate test was completed after 12 weeks of immersion in a similar solution at 125 C except that the aluminate concentration was reduced to 0.3 M. Visual inspection of the plate revealed that stress corrosion cracking had not initiated from the machined crack tips in the weld or in the heat affected zone. NDE ultrasonic testing also confirmed subsurface cracking did not occur. Based on these results, it can be concluded that the environmental condition of these tests was unable to develop stress corrosion cracking within the test periods for the small welded U-bends and for the large plates, which were welded with an identical procedure as used in the construction of the actual nuclear waste tanks in the 1960s. The

  4. INVESTIGATION OF THE POTENTIAL FOR CAUSTIC STRESS CORROSION CRACKING OF A537 CARBON STEEL NUCLEAR WASTE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    Lam, P.

    2009-10-15

    The evaporator recycle streams contain waste in a chemistry and temperature regime that may be outside of the current waste tank corrosion control program, which imposes temperature limits to mitigate caustic stress corrosion cracking (CSCC). A review of the recent service history (1998-2008) of Tanks 30 and 32 showed that these tanks were operated in highly concentrated hydroxide solution at high temperature. Visual inspections, experimental testing, and a review of the tank service history have shown that CSCC has occurred in uncooled/un-stress relieved F-Area tanks. Therefore, for the Type III/IIIA waste tanks the efficacy of the stress relief of welding residual stress is the only corrosion-limiting mechanism. The objective of this experimental program is to test carbon steel small scale welded U-bend specimens and large welded plates (12 x 12 x 1 in.) in a caustic solution with upper bound chemistry (12 M hydroxide and 1 M each of nitrate, nitrite, and aluminate) and temperature (125 C). These conditions simulate worst-case situations in Tanks 30 and 32. Both as-welded and stress-relieved specimens have been tested. No evidence of stress corrosion cracking was found in the U-bend specimens after 21 days of testing. The large plate test is currently in progress, but no cracking has been observed after 9 weeks of immersion. Based on the preliminary results, it appears that the environmental conditions of the tests are unable to develop stress corrosion cracking within the duration of these tests.

  5. Electro chemical studies on stress corrosion cracking of Incoloy-800 in caustic solution, part I: As received samples

    Directory of Open Access Journals (Sweden)

    Dinu Alice

    2005-01-01

    Full Text Available Many non-volatile impurities accidentally introduced into the steam generator tend to Concentrate on its surface in restricted flow areas. In this way these impurities can lead to stress corrosion cracking (SCC on stressed tubes of the steam generator. Such impurities can be strong alkaline or acid solutions. To evaluate the effect of alkaline concentrated environments on SCC of steam generator tubes, the tests were con ducted on stressed samples of Incoloy-800 in 10% NaOH solution. To accelerate the SCC process, stressed specimens were anodically polarised in a caustic solution in an electro chemical cell. The method of stressing of Incoloy-800 tubes used in our experiments was the C-ring. Using the cathodic zone of the potentiodynamic curves it was possible to calculate the most important electrochemical parameters: the corrosion current, the corrosion rate, and the polarization resistance. We found that the value of the corrosion potential to initiate the SCC microcracks was -100 mV. The tested samples were examined using the metallographic method. The main experimental results showed that the in crease of the stress state promoted the in crease of the SCC susceptibility of Incoloy-800 samples tested under the same conditions, and that the length of the SCC-type microcracks in creased with the growth of the stress value.

  6. Effects of Surface State and Applied Stress on Stress Corrosion Cracking of Alloy 690TT in Lead-containing Caustic Solution

    Institute of Scientific and Technical Information of China (English)

    Zhiming Zhang; Jianqiu Wang; En-Hou Han; Wei Ke

    2012-01-01

    The effects of surface state and applied stress on the stress corrosion cracking (SCC) behaviors of thermally treated (TT) Alloy 690 in 10 wt% NaOH solution with 100 mg/L litharge at 330 ℃ were investigated using C-ring samples with four kinds of surface states and two different stress levels. Sample outer surfaces of the first three kinds were ground to 400 grit (ground), shot-peened (SP) and electro-polished (EP) and the last one was used as the as-received state. Two samples of every kind were stressed to 100% and 200% yield stress of Alloy 690TT, respectively. The results showed that the oxide film consisted of three layers whereas continuous layer rich in Cr was not found. The poor adhesive ability indicated that the oxide film could not protect the matrix from further corrosion. Lead was found in the oxide film and the oxides at the crack paths and accelerated the dissolution of thermodynamically unstable Cr in these locations and also in the matrix. The crack initiation and propagation on Alloy 690TT were effectively retarded by SP and EP treatments but were enhanced by grinding treatment, compared with the cracks on the as-received surface. The cracking severity was also enhanced by increasing the externally applied stress. The accelerated dissolution of Cr and the local tensile stress concentration in the near-surface layer caused by cold-working and higher applied stress reduced the SCC-resistance of Alloy 690TT in the studied solution.

  7. Review on Stress Corrosion and Corrosion Fatigue Failure of Centrifugal Compressor Impeller

    Institute of Scientific and Technical Information of China (English)

    SUN Jiao; CHEN Songying; QU Yanpeng; LI Jianfeng

    2015-01-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  8. Industrial Experience on the Caustic Cracking of Stainless Steels and Nickel Alloys - A Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2005-10-09

    Caustic environments are present in several industries, from nuclear power generation to the fabrication of alkalis and alumina. The most common material of construction is carbon steel but its application is limited to a maximum temperature of approximately 80 C. The use of Nickel (Ni) alloys is recommended at higher temperatures. Commercially pure Ni is the most resistant material for caustic applications both from the general corrosion and the stress corrosion cracking (SCC) perspectives. Nickel rich alloys also offer a good performance. The most important alloying elements are Ni and chromium (Cr). Molybdenum (Mo) is not a beneficial alloying element and it dissolves preferentially from the alloy in presence of caustic environments. Austenitic stainless steels such as type 304 and 316 seem less resistant to caustic conditions than even plain carbon steel. Experimental evidence shows that the most likely mechanism for SCC is anodic dissolution.

  9. STRESS CORROSION CRACKING SUSCEPTIBILITY OF HIGH LEVEL WASTE TANKS DURING SLUDGE MASS REDUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, K

    2007-10-18

    Aluminum is a principal element in alkaline nuclear sludge waste stored in high level waste (HLW) tanks at the Savannah River Site. The mass of sludge in a HLW tank can be reduced through the caustic leaching of aluminum, i.e. converting aluminum oxides (gibbsite) and oxide-hydroxides (boehmite) into soluble hydroxides through reaction with a hot caustic solution. The temperature limits outlined by the chemistry control program for HLW tanks to prevent caustic stress corrosion cracking (CSCC) in concentrated hydroxide solutions will potentially be exceeded during the sludge mass reduction (SMR) campaign. Corrosion testing was performed to determine the potential for CSCC under expected conditions. The experimental test program, developed based upon previous test results and expected conditions during the current SMR campaign, consisted of electrochemical and mechanical testing to determine the susceptibility of ASTM A516 carbon steel to CSCC in the relevant environment. Anodic polarization test results indicated that anodic inhibition at the temperatures and concentrations of interest for SMR is not a viable, consistent technical basis for preventing CSCC. However, the mechanical testing concluded that CSCC will not occur under conditions expected during SMR for a minimum of 35 days. In addition, the stress relief for the Type III/IIIA tanks adds a level of conservatism to the estimates. The envelope for corrosion control is recommended during the SMR campaign is shown in Table 1. The underlying assumption is that solution time-in-tank is limited to the SMR campaign. The envelope recommends nitrate/aluminate intervals for discrete intervals of hydroxide concentrations, although it is recognized that a continuous interval may be developed. The limits also sets temperature limits.

  10. [Caustic ingestions].

    Science.gov (United States)

    Adukauskiene, Dalia; Mazeikiene, Sandra; Rumba, Arvydas; Vizgirdaite, Venta

    2009-01-01

    Caustic ingestions (alkalis, acids) may cause severe chemical burns and lifelong complications, which worsen life quality. Approximately 80% of caustic ingestions occur in children. They mostly intoxicate because of chemical substances kept insecurely or in inappropriate containers. Until now, there is no general opinion about diagnostics and management of caustic ingestions. Therefore, the main aim of this article is accurately represent diagnostic and treatment options believing that this information would help physicians to diagnose caustic ingestions easier and faster, to provide emergency management correctly, and to avoid acute and chronic complications.

  11. A Fundamental study of remedial technology development to prevent stress corrosion cracking of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Park, In Gyu; Lee, Chang Soon [Sunmoon University, Asan (Korea)

    1998-04-01

    Most of the PWR Steam generators with tubes in Alloy 600 alloy are affected by Stress Corrosion Cracking, such as PWSCC(Primary Water Stress Corrosion Cracking) and ODSCC(Outside Diameter Stress Corrosion Cracking). This study was undertaken to establish the background for remedial technology development to prevent SCC. in the report are included the following topics: (1) General: (i) water chemistry related factors, (ii) Pourbaix(Potential-pH) Diagram, (iii) polarization plot, (iv) corrosion mode of Alloy 600, 690, and 800, (v) IGA/SCC growth rate, (vi) material suspetibility of IGA/SCC, (vii) carbon solubility of Alloy 600 (2) Microstructures of Alloy 600 MA, Alloy 600 TT, Alloy 600 SEN Alloy 690 TT(Optical, SEM, and TEM) (3) Influencing factors for PWSCC initiation rate of Alloy 600: (i) microstructure, (ii) water chemistry(B, Li), (iii) temperature, (iv) plastic deformation, (v) stress relief annealing (4) Influencing factors for PWSCC growth rate of Alloy 600: (i) water chemistry(B, Li), (ii) Scott Model, (iii) intergranular carbide, (iv) temperature, (v) hold time (5) Laboratory conditions for ODSCC initiation rate: 1% NaOH, 316 deg C; 1% NaOH, 343 deg C; 50% NaOH, 288 deg C; 10% NaOH, 302 deg C; 10% NaOH, 316 deg C; 50% NaOH, 343 deg C (6) Sludge effects for ODSCC initiation rate: CuO, Cr{sub 2}O{sub 3}, Fe{sub 3}O{sub 4} (7) Influencing factors for PWSCC growth rate of Alloy 600: (i) Caustic concentration effect, (ii) carbonate addition effect (8) Sulfate corrosion: (i) sulfate ratio and pH effect, (ii) wastage rate of Alloy 600 and Alloy 690 (9) Crevice corrosion: (i) experimental setup for crevice corrosion, (ii) organic effect, (iii) (Na{sub 2}SO{sub 4} + NaOH) effect (10) Remedial measures for SCC: (i) Inhibitors, (ii) ZnO effect. (author). 30 refs., 174 figs., 51 tabs.

  12. Stress Corrosion Cracking of Pipeline Steels

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper provides a review of the differences between high pH and near-neutral pH stress corrosion cracking ofpipeline steels, influencing factors, and mechanisms. The characteristics and historical information on both forms ofSCC are discussed. The prospect for research in the future is also presented.

  13. Relativity between corrosion-induced stress and stress corrosion cracking of brass in an ammonia solution

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The susceptibility to stress corrosion cracking (SCC) of brass in an ammonia solution with various pH values or under various applied potentials was measured at slow strain rate tests. The additive stress in the same solution was measured using two methods. The results indicate that the variation of the susceptibility to SCC with pH value or with potential is in an excellent agreement with the corrosion (passive film or dezincification layer)-induced stress. When pH ? 7, the corrosion-induced tensile stress and the susceptibility to SCC have maximum values and hardly change with increasing the pH value. However, when pH < 7, both the corrosion-induced tensile stress and the susceptibility to SCC reduce rapidly with decreasing the pH value. Both the corrosion-induced tensile stress and the susceptibility to SCC have maximum values at the open-circuit potential, decrease slightly under the anodic polarization, and reduce gradually to zero under the cathodic polarization.

  14. Stress-corrosion cracking of titanium alloys.

    Science.gov (United States)

    Blackburn, M. J.; Feeney, J. A.; Beck, T. R.

    1973-01-01

    In the light of research material published up to May 1970, the current understanding of the experimental variables involved in the stress-corrosion cracking (SCC) behavior of titanium and its alloys is reviewed. Following a brief summary of the metallurgy and electrochemistry of titanium alloys, the mechanical, electrochemical, and metallurgical parameters influencing SCC behavior are explored with emphasis on crack growth kinetics. Macro- and microfeatures of fractures are examined, and it is shown that many transgranular SCC failures exhibit morphological and crystallographic features similar to mechanical cleavage failures. Current SCC models are reviewed with respect to their ability to explain the observed SCC behavior of titanium and its alloys. Possible methods for eliminating or minimizing stress corrosion hazards in titanium or titanium alloy components are described.

  15. Stress-Assisted Corrosion in Boiler Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Preet M Singh; Steven J Pawel

    2006-05-27

    A number of industrial boilers, including in the pulp and paper industry, needed to replace their lower furnace tubes or decommission many recovery boilers due to stress-assisted corrosion (SAC) on the waterside of boiler tubes. More than half of the power and recovery boilers that have been inspected reveal SAC damage, which portends significant energy and economic impacts. The goal of this project was to clarify the mechanism of stress-assisted corrosion (SAC) of boiler tubes for the purpose of determining key parameters in its mitigation and control. To accomplish this in-situ strain measurements on boiler tubes were made. Boiler water environment was simulated in the laboratory and effects of water chemistry on SAC initiation and growth were evaluated in terms of industrial operations. Results from this project have shown that the dissolved oxygen is single most important factor in SAC initiation on carbon steel samples. Control of dissolved oxygen can be used to mitigate SAC in industrial boilers. Results have also shown that sharp corrosion fatigue and bulbous SAC cracks have similar mechanism but the morphology is different due to availability of oxygen during boiler shutdown conditions. Results are described in the final technical report.

  16. Stress corrosion cracking of titanium alloys

    Science.gov (United States)

    Statler, G. R.; Spretnak, J. W.; Beck, F. H.; Fontana, M. G.

    1974-01-01

    The effect of hydrogen on the properties of metals, including titanium and its alloys, was investigated. The basic theories of stress corrosion of titanium alloys are reviewed along with the literature concerned with the effect of absorbed hydrogen on the mechanical properties of metals. Finally, the basic modes of metal fracture and their importance to this study is considered. The experimental work was designed to determine the effects of hydrogen concentration on the critical strain at which plastic instability along pure shear directions occurs. The materials used were titanium alloys Ti-8Al-lMo-lV and Ti-5Al-2.5Sn.

  17. An overview of materials degradation by stress corrosion in PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Scott, P. M. [Framatome ANP, Tour Areva, 92084 Paris La Defense Cedex (France)

    2004-07-01

    The aging of water cooled and moderated nuclear steam supply systems has given rise to many material corrosion problems of which stress corrosion cracking has proved to be one of the most serious. The aim of this paper is to review some examples of corrosion and particularly stress corrosion problems from the author's experience of interpreting and modelling these phenomena in PWR systems. Examples of stress corrosion cracking in PWR systems described include the major issue of Alloy 600 intergranular cracking in primary PWR coolants, for which it is generally perceived that both adequate life prediction models and remedial measures now exist. Intergranular corrosion and stress corrosion cracking of Alloy 600 steam generator tubes that occur in occluded superheated crevices on the secondary side of steam generators due to hide-out and concentration of water borne impurities are also addressed. Rather less extensive or well known examples are discussed such as the stress corrosion cracking of carbon and low alloy steels and of stainless steels in occluded dead-leg situations where it is sometimes difficult to guarantee adequate control of water chemistry, particularly at plant start-up. Reference is also be made to the use of high strength fastener materials in PWR systems as well as to the emerging issue of the effect of high neutron doses on the stress corrosion resistance of core structural components fabricated from austenitic stainless steels. (authors)

  18. Relationship among Parameters Evaluating Stress Corrosion Cracking

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The threshold stress, σc, for sulfide stress corrosion cracking (SCC) of seven pipeline steels and five other steels, the critical stress, SC, for seven pipeline steels and two drill rod steels with various strengths and the susceptibility to SCC, IRA or σf(SCC)/σf, for four pipeline steels, two drill rod steels and five other steels were measured. The results showed that there are no definite elationships among σc, SC and IRA or σf(SCC)/σf. The threshold stress for hydrogen induced cracking (HIC) during charging with loading in the H2SO4 solution, σc(H), decreased linearly with logarithm of the concentration of diffusible hydrogen c0, i.e., σC(H)=A-B Inc0 for four pipeline steels. σc(H) obtained with a special cathodic current ic, which was corresponding to the diffusible hydrogen concentration during immersing in the H2S solution, were consistent with σc for sulfide SCC for four pipeline steels.Therefore, σc for sulfide SCC can be measured using dynamically charging in the H2SO4 solution with the special cathodic current ic.

  19. A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-08-21

    The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.

  20. Sizing stress corrosion cracks using laser ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Hamood; McNealy, Rick; Fingerhut, Martin [Applus-RTD. Houston, TX (United States); Klein, Marvin; Ansari, Homayoon [Intelligent Optical Systems, Inc. Los Angeles, CA (United States); Kania Richard [TransCanada. Calgary, AB (Canada); Rapp, Steve [Spectra Energy, Houston, TX (United States)

    2010-07-01

    Despite various efforts, no reliable tools and techniques are available to enable an operator to quantify the impact of an SCC (Stress Corrosion Cracking) colony on the safety and integrity of a pipeline. Reliable non-destructive detection and measurement tools are not available either. There is therefore a large gap between current technology and the needs of the pipeline industry. Recent developments promise that with a concentrated effort, a comprehensive solution can be devised. This paper describes technical work performed to develop and validate both the inspection tool and the time of flight diffraction (TOFD) technique for sizing the depth of SCC. It also presents preliminary results of work on a closely related project that provides, on the basis of this technology, an integrated approach and tool for mapping, sizing, and evaluating SCC, through which significant cracks are filtered from more benign cracks within an SCC colony.

  1. Experimental Study on Wing Crack Behaviours in Dynamic-Static Superimposed Stress Field Using Caustics and High-Speed Photography

    Directory of Open Access Journals (Sweden)

    L.Y. Yang

    2014-07-01

    Full Text Available During the drill-and-blast progress in rock tunnel excavation of great deep mine, rock fracture is evaluated by both blasting load and pre-exiting earth stress (pre-compression. Many pre-existing flaws in the rock mass, like micro-crack, also seriously affect the rock fracture pattern. Under blasting load with pre-compression, micro-cracks initiate, propagate and grow to be wing cracks. With an autonomous design of static-dynamic loading system, dynamic and static loads were applied on some PMMA plate specimen with pre-existing crack, and the behaviour of the wing crack was tested by caustics corroding with a high-speed photography. Four programs with different static loading modes that generate different pre-compression fields were executed, and the length, velocity of the blasting wing crack and dynamic stress intensity factor (SIF at the wing crack tip were analyzed and discussed. It is found that the behaviour of blasting-induced wing crack is affected obviously by blasting and pre-compression. And pre-compression, which is vertical to the direction of the wing crack propagation, hinders the crack propagation. Furthermore, the boundary constraint condition plays an important role on the behaviour of blasting induced crack during the experiment.

  2. Stress corrosion cracking of brass in ammonia solution

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Brass foil with a protective layer formed on one side was deflected during corrosion in an ammonia solution under various applied potentials, and then corrosion-induced stress generated at brass/dezincification layer under different potentials could be measured. At the same time, susceptibility to stress corrosion cracking(SCC) of brass in the ammonia solution under various applied potentials was measured using a single-edge notched specimen. At open-circuit potential, both corrosion-induced tensile stress and susceptibility to SCC(Iσ) had a maximum value. Both tensile stress σp and susceptibility Iσ decreased slightly under anodic polarization, but reduced steeply with the decrease in potential of cathodic polarization. At the cathodic potential of -500  mV(vs SCE), corrosion-induced stress became compressive because of copper-plating layer, correspondingly, susceptibility to SCC was zero. Therefore, the variation of SCC susceptibility with potential is consistent with that of the corrosion-induced additive stress.

  3. De-alloying and stress-corrosion cracking. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sieradzki, K.

    1998-09-01

    This research program has had two major areas of focus that are related: (1) alloy corrosion and (2) the role of selective dissolution in the stress corrosion cracking of alloy systems. These interrelated issues were examined using model systems such as Ag-Au and Cu-Au by conventional electrochemical techniques, in situ scanning tunneling microscopy (STM), in situ small angle neutron scattering (SANS), ultrahigh speed digital photography of fracture events, and computer simulations. The STM and SANS work were specifically aimed at addressing a roughening transition known to occur in alloy systems undergoing corrosion at electrochemical potentials greater than the so-called critical potential. Analytical models of de-alloying processes including the roughening transition were developed that specifically include curvature effects that are important in alloy corrosion processes. Stress-corrosion experiments were performed on the same model systems using rapid optical and electrochemical techniques on 50 {micro}m--250 {micro}m thick sheets and small diameter wires. The primary goal of this work was to develop a fundamental understanding of the corrosion and electrochemistry of alloys and the stress-corrosion cracking processes these alloys undergo. Computer simulations and analytical work identified surface stress and an important parameter in environmentally assisted fracture. The major results of the research on this program since the summer of 1993 are briefly summarized.

  4. Stress corrosion cracking of copper canisters

    Energy Technology Data Exchange (ETDEWEB)

    King, Fraser (Integrity Corrosion Consulting Limited (Canada)); Newman, Roger (Univ. of Toronto (Canada))

    2010-12-15

    A critical review is presented of the possibility of stress corrosion cracking (SCC) of copper canisters in a deep geological repository in the Fennoscandian Shield. Each of the four main mechanisms proposed for the SCC of pure copper are reviewed and the required conditions for cracking compared with the expected environmental and mechanical loading conditions within the repository. Other possible mechanisms are also considered, as are recent studies specifically directed towards the SCC of copper canisters. The aim of the review is to determine if and when during the evolution of the repository environment copper canisters might be susceptible to SCC. Mechanisms that require a degree of oxidation or dissolution are only possible whilst oxidant is present in the repository and then only if other environmental and mechanical loading conditions are satisfied. These constraints are found to limit the period during which the canisters could be susceptible to cracking via film rupture (slip dissolution) or tarnish rupture mechanisms to the first few years after deposition of the canisters, at which time there will be insufficient SCC agent (ammonia, acetate, or nitrite) to support cracking. During the anaerobic phase, the supply of sulphide ions to the free surface will be transport limited by diffusion through the highly compacted bentonite. Therefore, no HS. will enter the crack and cracking by either of these mechanisms during the long term anaerobic phase is not feasible. Cracking via the film-induced cleavage mechanism requires a surface film of specific properties, most often associated with a nano porous structure. Slow rates of dissolution characteristic of processes in the repository will tend to coarsen any nano porous layer. Under some circumstances, a cuprous oxide film could support film-induced cleavage, but there is no evidence that this mechanism would operate in the presence of sulphide during the long-term anaerobic period because copper sulphide

  5. Film-induced stress enhancing stress corrosion cracking of austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    李金许; 陈浩; 王燕斌; 乔利杰; 褚武扬

    2001-01-01

    A constant deflection device designed for use within a transmission electron microscopy (TEM) was used to investigate the change in dislocation configuration ahead of a crack tip during stress corrosion cracking (SCC) of type 310 austenitic stainless steel in a boiling MgCl2 solution, and the initiation process of stress corrosion microcrack. Results showed that corrosion process during SCC enhanced dislocation emission, multiplication and motion. Microcracks of SCC were initiated when the corrosion-enhanced dislocation emission and motion reached critical state.   A passive film formed during corrosion of austenitic stainless steel in the boiling MgCl2 solution generated a tensile stress. During SCC, the additive tensile stress generated at the metal/passive film interface helps enhance dislocation emission and motion.

  6. Three-dimensional characterization of stress corrosion cracks

    DEFF Research Database (Denmark)

    Lozano-Perez, S.; Rodrigo, P.; Gontard, Lionel Cervera

    2011-01-01

    Understanding crack propagation and initiation is fundamental if stress corrosion cracking (SCC) mechanisms are to be understood. However, cracking is a three-dimensional (3D) phenomenon and most characterization techniques are restricted to two-dimensional (2D) observations. In order to overcome...... the best spatial resolution. To illustrate the power of these techniques, different parts of dominant stress corrosion cracks in Ni-alloys and stainless steels have been reconstructed in 3D. All relevant microstructural features can now be studied in detail and its relative orientation respect...

  7. MECHANISTIC UNDERSTANDING OF CAUSTIC CRACKING OF CARBON STEELS

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Diaz, B.; Roy, A.

    2009-10-19

    Liquid waste generated by the PUREX process for separation of nuclear materials is concentrated and stored in Type IV single-shell carbon steel tanks at the Savannah River Site (SRS). The Type IV tanks for this waste do not have cooling coils and have not undergone heat treatment to stress-relieve the tanks. After the waste is concentrated by evaporation, it becomes very alkaline and can cause stress corrosion cracking (SCC) and pitting corrosion of the tank materials. SRS has experienced leakage from non-stress-relieved waste tanks constructed of A285 carbon steel and pitting of A212 carbon steel tanks in the vapor space. An investigation of tank materials has been undertaken at SRS to develop a basic understanding of caustic SCC of A285 and A212 grade carbon steels exposed to aqueous solutions, primarily containing sodium hydroxide (NaOH), sodium nitrate (NaNO{sub 3}), and sodium nitrite (NaNO{sub 2}) at temperatures relevant to the operating conditions of both the F and H area plants. This report presents the results of this corrosion testing program. Electrochemical tests were designed using unstressed coupons in a simulated tank environment. The purpose of this testing was to determine the corrosion susceptibility of the tank materials as a function of chemical concentration, pH, and temperature. A285 and A516 (simulates A212 carbon steel) coupons were used to investigate differences in the corrosion of these carbon steels. Electrochemical testing included measurement of the corrosion potential and polarization resistance as well as cyclic potentiodynamic polarization (CPP) testing of coupons. From the CPP experiments, corrosion characteristics were determined including: corrosion potential (E{sub corr}), pitting or breakdown potential (E{sub pit}), and repassivation potential (E{sub prot}). CPP results showed no indications of localized corrosion, such as pitting, and all samples showed the formation of a stable passive layer as evidenced by the positive

  8. Chemical milling solution reveals stress corrosion cracks in titanium alloy

    Science.gov (United States)

    Braski, D. N.

    1967-01-01

    Solution of hydrogen flouride, hydrogen peroxide, and water reveals hot salt stress corrosion cracks in various titanium alloys. After the surface is rinsed in water, dried, and swabbed with the solution, it can be observed by the naked eye or at low magnification.

  9. Effect of hydrogen on stress corrosion cracking of copper

    Institute of Scientific and Technical Information of China (English)

    Li-jie QIAO

    2008-01-01

    The effects of hydrogen on electrochemical behavior and susceptibility of stress corrosion cracking (SCC) of pure copper were studied. SCC susceptibility of pure copper in a 1 M NaNO2 solution was increased by pre-charged hydrogen. The effect of hydrogen on the sus-ceptibility is more obvious in the low stress region due to the longer fracture time, which resulted in a longer time for more hydrogen to diffuse toward the crack tip. Synergistic effects of hydrogen and stress on corrosion and SCC pro-cesses were discussed. The results showed that an inter-action between stress and hydrogen at the crack tip could increase the anodic dissolution rate remarkably.

  10. EXPERT PANEL OVERSIGHT COMMITTEE ASSESSMENT OF FY2008 CORROSION AND STRESS CORROSION CRACKING SIMULANT TESTING PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER KD

    2009-01-08

    The Expert Panel Oversight Committee (EPOC) has been overseeing the implementation of selected parts of Recommendation III of the final report, Expert Panel workshop for Hanford Site Double-Shell Tank Waste Chemistry Optimization, RPP-RPT-22126. Recommendation III provided four specific requirements necessary for Panel approval of a proposal to revise the chemistry control limits for the Double-Shell Tanks (DSTs). One of the more significant requirements was successful performance of an accelerated stress corrosion cracking (SCC) experimental program. This testing program has evaluated the optimization of the chemistry controls to prevent corrosion in the interstitial liquid and supernatant regions of the DSTs.

  11. Caustics for Spherical Waves

    CERN Document Server

    de Rham, Claudia

    2016-01-01

    We study the development of caustics in shift-symmetric scalar field theories by focusing on simple waves with an $SO(p)$-symmetry in an arbitrary number of space dimensions. We show that the Galileon and the DBI-Galileon naturally emerge as the unique set of caustic-free theories, highlighting a link between the caustic-free condition for simple $SO(p)$-waves and the existence of either a global galilean symmetry or a global relativistic galilean symmetry.

  12. Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance

    Science.gov (United States)

    Canto Maya, Christian M.

    In oil and gas production, internal corrosion of pipelines causes the highest incidence of recurring failures. Ensuring the integrity of ageing pipeline infrastructure is an increasingly important requirement. One of the most widely applied methods to reduce internal corrosion rates is the continuous injection of chemicals in very small quantities, called corrosion inhibitors. These chemical substances form thin films at the pipeline internal surface that reduce the magnitude of the cathodic and/or anodic reactions. However, the efficacy of such corrosion inhibitor films can be reduced by different factors such as multiphase flow, due to enhanced shear stress and mass transfer effects, loss of inhibitor due to adsorption on other interfaces such as solid particles, bubbles and droplets entrained by the bulk phase, and due to chemical interaction with other incompatible substances present in the stream. The first part of the present project investigated the electrochemical behavior of two organic corrosion inhibitors (a TOFA/DETA imidazolinium, and an alkylbenzyl dimethyl ammonium chloride), with and without an inorganic salt (sodium thiosulfate), and the resulting enhancement. The second part of the work explored the performance of corrosion inhibitor under multiphase (gas/liquid, solid/liquid) flow. The effect of gas/liquid multiphase flow was investigated using small and large scale apparatus. The small scale tests were conducted using a glass cell and a submersed jet impingement attachment with three different hydrodynamic patterns (water jet, CO 2 bubbles impact, and water vapor cavitation). The large scale experiments were conducted applying different flow loops (hilly terrain and standing slug systems). Measurements of weight loss, linear polarization resistance (LPR), and adsorption mass (using an electrochemical quartz crystal microbalance, EQCM) were used to quantify the effect of wall shear stress on the performance and integrity of corrosion inhibitor

  13. Hydrogen-increased dezincification layer-induced stress and susceptibility to stress corrosion cracking of brass

    Institute of Scientific and Technical Information of China (English)

    李会录; 高克玮; 褚武扬; 刘亚萍; 乔利杰

    2003-01-01

    Dezincification layer formed during corrosion or stress corrosion cracking (SCC) of brass in an ammonia solution could induce an additive stress. The effect of hydrogen on the dezincification layer-induced stress and the susceptibility to SCC were studied. The dezincification layer-induced stress was measured using the deflection method and the flowing stress differential method, respectively. The latter measures the difference between the flowing stress of a specimen before unloading and the yield stress of the same specimen after unloading and forming a dezincification layer. The susceptibility to SCC was measured using slow strain rate test. Results show that both the dezincification layer-induced stress and the susceptibility to SCC increase with increasing hydrogen concentration in a specimen. This implies that hydrogen-enhanced dezincification layer-induced stress is consistence with the hydrogen-increased susceptibility to SCC of brass in the ammonia solution.

  14. The Effect of Welding Residual Stress for Making Artificial Stress Corrosion Crack in the STS 304 Pipe

    Directory of Open Access Journals (Sweden)

    Jae-Seong Kim

    2015-01-01

    Full Text Available The stress corrosion crack is one of the fracture phenomena for the major structure components in nuclear power plant. During the operation of a power plant, stress corrosion cracks are initiated and grown especially in dissimilar weldment of primary loop components. In particular, stress corrosion crack usually occurs when the following three factors exist at the same time: susceptible material, corrosive environment, and tensile stress (residual stress included. Thus, residual stress becomes a critical factor for stress corrosion crack when it is difficult to improve the material corrosivity of the components and their environment under operating conditions. In this study, stress corrosion cracks were artificially produced on STS 304 pipe itself by control of welding residual stress. We used the instrumented indentation technique and 3D FEM analysis (using ANSYS 12 to evaluate the residual stress values in the GTAW area. We used the custom-made device for fabricating the stress corrosion crack in the inner STS 304 pipe wall. As the result of both FEM analysis and experiment, the stress corrosion crack was quickly generated and could be reproduced, and it could be controlled by welding residual stress.

  15. Three-dimensional characterization of stress corrosion cracks

    Energy Technology Data Exchange (ETDEWEB)

    Lozano-Perez, S., E-mail: sergio.lozano-perez@materials.ox.ac.u [University of Oxford, Department of Materials, Parks Road, Oxford OX1 3PH (United Kingdom); Rodrigo, P. [Universidad Rey Juan Carlos, Dpto. de Ciencia e Ingenieria de Materiales, c/ Tulipan s.n., 28933 Mostoles (Madrid) (Spain); Gontard, Lionel C. [Danish Technical University, Center for Electron Nanoscopy, Matematiktorvet Building 307, Room 115, 2800 Kogens Lyngby (Denmark)

    2011-01-31

    Understanding crack propagation and initiation is fundamental if stress corrosion cracking (SCC) mechanisms are to be understood. However, cracking is a three-dimensional (3D) phenomenon and most characterization techniques are restricted to two-dimensional (2D) observations. In order to overcome this problem, different approaches to extract 3D information have been used in the recent years. In this work we will present the benefits of using 3D focused ion beam (FIB) slicing and electron tomography. 3D FIB slicing offers a fast and high throughput characterization while electron tomography offers the best spatial resolution. To illustrate the power of these techniques, different parts of dominant stress corrosion cracks in Ni-alloys and stainless steels have been reconstructed in 3D. All relevant microstructural features can now be studied in detail and its relative orientation respect to the strain direction and grain boundary plane accurately measured.

  16. Susceptibility to Stress Corrosion Cracking of 254SMO SS

    Directory of Open Access Journals (Sweden)

    De Micheli Lorenzo

    2002-01-01

    Full Text Available The susceptibility to stress corrosion cracking (SCC of solubilized and sensitized 254SMO SS was studied in sodium chloride, and sodium fluoride solutions at 80 °C and sulfuric acid solutions in presence of sodium chloride at 25 °C. The influence of salt concentration, pH values and the addition of thiosulfate was examined. The susceptibility to SCC was evaluated by Slow Strain Rate Tests (SSRT, at 1.5 x 10-6 s-1 strain rate. The behavior of 254SMO was compared to those of AISI 316L SS and Hastelloy C276. 254SMO showed an excellent resistance to SCC in all conditions, except in the more acidic solutions (pH <= 1 where, in the sensitized conditions, intergranular stress corrosion cracking occurred.

  17. Intercrystalline Stress Corrosion of Inconel 600 Inspection Tubes in the Aagesta Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Groenwall, B.; Ljungberg, L.; Huebner, W.; Stuart, W.

    1966-08-15

    caustic solutions and in plain, pure high-temperature water. At this stage it seems most difficult to establish which of these cases is relevant to the Aagesta failure. This is especially true as both these conditions give the same type of intercrystalline cracks, The possible influence of cold work, i. e. residual stresses, originating from milling, indicate the necessity of more stringent delivery control. Also the probable effect of carbides and other precipitates should be avoided by selecting a low carbon, pure iron-nickel-chromium alloy, preferably vacuum-melted. The failures encountered show that Inconel 600 under certain conditions may be susceptible to inter-crystalline stress corrosion cracking in alkaline high-temperature water. It remains to be shown if a satisfactory performance of Inconel 600 for long operating periods can be obtained under similar conditions in water-cooled reactors by proper manufacturing control and judicious design, omitting high stresses and crevices.

  18. Stress corrosion cracking of austenitic stainless steel core internal welds.

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Park, J.-H.; Ruther, W. E.; Sanecki, J. E.; Strain, R. V.; Zaluzec, N. J.

    1999-04-14

    Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that had cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L, as well as 304 SS core shroud welds and mockup shielded-metal-arc welds, were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on the grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine, which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests also indicate that fluorine exacerbates the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of core shroud welds.

  19. Corrosion and stress corrosion cracking of ferritic/martensitic steel in super critical pressurized water

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, T. [Naka Fusion Research Institute, JAEA, 801-1 Mukouyama, Naka, Ibaraki 311-0193 (Japan)]. E-mail: hirose.takanori@jaea.go.jp; Shiba, K. [Naka Fusion Research Institute, JAEA, 801-1 Mukouyama, Naka, Ibaraki 311-0193 (Japan); Enoeda, M. [Naka Fusion Research Institute, JAEA, 801-1 Mukouyama, Naka, Ibaraki 311-0193 (Japan); Akiba, M. [Naka Fusion Research Institute, JAEA, 801-1 Mukouyama, Naka, Ibaraki 311-0193 (Japan)

    2007-08-01

    A water-cooled solid breeder (WCSB) blanket cooled by high temperature SCPW (super critical pressurized water) is a practical option of DEMO reactor. Therefore, it is necessary to check the compatibility of the steel with SCPW. In this work, reduced activation ferritic/martensitic steel, F82H has been tested through slow strain rate tests (SSRT) in 23.5 MPa SCPW. And weight change behavior was measured up to 1000 h. F82H did not demonstrated stress corrosion cracking and its weight simply increased with surface oxidation. The weight change of F82H was almost same as commercial 9%-Cr steels. According to a cross-sectional analysis and weight change behavior, corrosion rate of F82H in the 823 K SCPW is estimated to be 0.04 mm/yr.

  20. Sensitization, intergranular attack, stress corrosion cracking, and irradiation effects on the corrosion of iron--chromium--nickel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P.C.S.

    1978-04-01

    A literature review is presented on the sensitization, intergranular attack, and stress corrosion cracking of austenitic stainless steels with emphasis on dilute solutions at temperatures below the boiling point of water. An attempt is made to list the possible sources of contaminants during manufacture, shipping, construction and all phases of operation of the sodium containing components. The susceptibility of the different materials to stress corrosion cracking in the various contaminants is discussed and suggestions to prevent serious problems are made. (GHT)

  1. Modeling Threshold of Stress Intensity Factor in Iodine Induced Stress Corrosion Crack of Zirconium

    Institute of Scientific and Technical Information of China (English)

    SHANG; Xin-yuan; CHEN; Peng

    2013-01-01

    KISCC,which is the threshold of stress intensity factor of iodine induced stress corrosion crack(ISCC)of Zirconium,reflects the susceptibility of ISCC of zirconium.Once the stress intensity factor surpasses the threshold,the cracking propagation modality in material will transform to transgranular from intergranular immediately and the velocity of the cracking will increase rapidly.Four key factors that’s

  2. Environmental Cracking of Corrosion Resistant Alloys in the Chemical Process Industry - A Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2006-12-04

    A large variety of corrosion resistant alloys are used regularly in the chemical process industry (CPI). The most common family of alloys include the iron (Fe)-based stainless steels, nickel (Ni) alloys and titanium (Ti) alloys. There also other corrosion resistant alloys but their family of alloys is not as large as for the three groups mentioned above. All ranges of corrosive environments can be found in the CPI, from caustic solutions to hot acidic environments, from highly reducing to highly oxidizing. Stainless steels are ubiquitous since numerous types of stainless steels exist, each type tailored for specific applications. In general, stainless steels suffer stress corrosion cracking (SCC) in hot chloride environments while high Ni alloys are practically immune to this type of attack. High nickel alloys are also resistant to caustic cracking. Ti alloys find application in highly oxidizing solutions. Solutions containing fluoride ions, especially acid, seem to be aggressive to almost all corrosion resistant alloys.

  3. Space-time caustics

    Directory of Open Access Journals (Sweden)

    Arthur D. Gorman

    1986-01-01

    Full Text Available The Lagrange manifold (WKB formalism enables the determination of the asymptotic series solution of linear differential equations modelling wave propagation in spatially inhomogeneous media at caustic (turning points. Here the formalism is adapted to determine a class of asymptotic solutions at caustic points for those equations modelling wave propagation in media with both spatial and temporal inhomogeneities. The analogous Schrodinger equation is also considered.

  4. Stress corrosion cracking in canistered waste package containers: Welds and base metals

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.S.

    1998-03-01

    The current design of waste package containers include outer barrier using corrosion allowable material (CAM) such as A516 carbon steel and inner barrier of corrosion resistant material (CRM) such as alloy 625 and C22. There is concern whether stress corrosion cracking would occur at welds or base metals. The current memo documents the results of our analysis on this topic.

  5. The corrosion and stress corrosion cracking behavior of a novel alumina-forming austenitic stainless steel in supercritical water

    Science.gov (United States)

    Sun, Hongying; Yang, Haijie; Wang, Man; Giron-Palomares, Benjamin; Zhou, Zhangjian; Zhang, Lefu; Zhang, Guangming

    2017-02-01

    The general corrosion and stress corrosion behavior of Fe-27Ni-15Cr-5Al-2Mo-0.4Nb alumina-forming austenitic (AFA) steel were investigated in supercritical water under different conditions. A double layer oxide structure was formed: a Fe-rich outer layer (Fe2O3 and Fe3O4) and an Al-Cr-rich inner layer. And the inner layer has a low growth rate with exposing time, which is good for improvement of corrosion resistance. Additionally, some internal nodular Al-Cr-rich oxides were also observed, which resulted in a local absence of inner layer. Stress corrosion specimens exhibited a combination of high strength, good ductility and low susceptibility. The stress strength and elongation was reduced by increasing temperature and amount of dissolved oxygen. In addition, the corresponding susceptibility was increased with decreased temperatures and increased oxygen contents.

  6. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  7. Stress corrosion cracking and hydrogen embrittlement of thick section high strength low alloy steel.

    OpenAIRE

    Needham, William Donald

    1986-01-01

    An experimental study was conducted to evaluate the corrosion performance of weldments of a high strength low alloy(HSLA) steel in a simulated seawater environment. This steel, designated HSLA80, was developed by the United States Navy for use in ship structural applications. Stress corrosion CRACKING(SCC) and hydrogen embrittlement(HEM) were investigated by conducting 42 Wedge-Opening load(WOL) tests as a function of stress intensity and corrosion potential and 33 Slow Strain Rate(SSR) tests...

  8. Advances in research of stress-assisted corrosion fatigue problem

    Institute of Scientific and Technical Information of China (English)

    TANG Zhi-bo; LI Qiang

    2007-01-01

    Ceramic materials are notable for their rigidity, insulation and resistance to hostile environment. Nevertheless, if a stressed ceramic component is exposed to chemical attack, it may suffer from a form of delayed fracture known as static fatigue.From the point of view of a designer, it is clearly desirable to determine the behavior of sub-critical crack growth; the crack path and crack growth rate, as a function of material properties and loading conditions are of particular interest. This paper presents a review of advances in stress assisted corrosion problem in history and its corresponding numerical approaches in the last decades,and finally, comes up with consideration and crucial suggestions for future work.

  9. EFFECTS OF CHEMISTRY AND OTHER VARIABLES ON CORROSION AND STRESS CORROSION CRACKING IN HANFORD DOUBLE SHELL TANKS

    Energy Technology Data Exchange (ETDEWEB)

    BROWN MH

    2008-11-13

    Laboratory testing was performed to develop a comprehensive understanding of the corrosivity of the tank wastes stored in Double-Shell Tanks using simulants primarily from Tanks 241-AP-105, 241-SY-103 and 241-AW-105. Additional tests were conducted using simulants of the waste stored in 241-AZ-102, 241-SY-101, 241-AN-107, and 241-AY-101. This test program placed particular emphasis on defining the range of tank waste chemistries that do not induce the onset of localized forms of corrosion, particularly pitting and stress corrosion cracking. This document summarizes the key findings of the research program.

  10. Threshold Stress Intensity of Hydrogen-Induced Cracking and Stress Corrosion Cracking of High Strength Steel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The threshold stress intensity of stress corrosion cracking (SCC) for 40CrMo steel in 3.5 % NaCl solution decreased exponentially with the increase of yield strength. The threshold stress intensity of hydrogen-induced cracking during dynamical charging for 40CrMo steel decreased linearly with the logarithm of the concentration of diffusible hydrogen. This equation was also applicable to SCC of high strength steel in aqueous solution. The critical hydrogen enrichment concentration necessary for SCC of high strength steel in water decreased exponentially with the increase of yield strength. Based on the results, the relationship between KISCC and σys could be deduced.

  11. Interplay of microbiological corrosion and alloy microstructure in stress corrosion cracking of weldments of advanced stainless steels

    Indian Academy of Sciences (India)

    R K Singh Raman

    2003-06-01

    This paper presents an overview of the phenomenon of stress corrosion cracking (SCC) of duplex stainless steels and their weldments in marine environments and the potential role of microbial activity in inducing SCC susceptibility. As a precursor to the topic the paper also reviews the performance of the traditional corrosion-resistant alloys and their weldments and the necessity of using duplex stainless steels (DSS), in order to alleviate corrosion problems in marine environments. Given that the performance of weldments of such steels is often unsatisfactory, this review also assesses the research needs in this area. In this context the paper also discusses the recent reports on the role of microorganisms in inducing hydrogen embrittlements and corrosion fatigue.

  12. Behavior of Stress Corrosion Cracking in a Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    SONG Renguo; YANG Fanger; BLAWERT Carsten; DIETZEL Wolfgang

    2009-01-01

    Slow strain rate testing (SSRT) was employed to study the stress corrosion cracking (SCC) behavior of ZE41 magnesium alloy in 0.01 M NaCl solution. Smooth tensile specimens with different thicknesses were strained dynamically in both longitudinal and transverse direction under permanent immersions at a strain rate of 10-6 s-1. It is found that ZE41 magnesium alloy is susceptible to SCC in 0.01 M NaCl solution. The SCC susceptibility of the thinner specimen is lower than that of the thicker specimen. Also, the longitudinal specimens are slightly more susceptible to SCC than the transverse specimens. The SCC mechanism of magnesium alloy is attributed to the combination of anodic dissolution with hydrogen embrittlement.

  13. Hierarchical petascale simulation framework for stress corrosion cracking

    Science.gov (United States)

    Vashishta, P.; Kalia, R. K.; Nakano, A.; Kaxiras, E.; Grama, A.; Lu, G.; Eidenbenz, S.; Voter, A. F.; Hood, R. Q.; Moriarty, J. A.; Yang, L. H.

    2008-07-01

    We are developing a scalable parallel and distributed computational framework consisting of methods, algorithms, and integrated software tools for multi-terascle-to-petascale simulations of stress corrosion cracking (SCC) with quantum-level accuracy. We have performed multimillion- to billion-atom molecular dynamics (MD) simulations of deformation, flow, and fracture in amorphous silica with interatomic potentials and forces validated by density functional theory (DFT) calculations. Optimized potentials have been developed to study sulfur embrittlement of nickel with multimillion-to-multibillion atom MD simulations based on DFT and temperature dependent model generalized pseudopotential theory. We have also developed a quasi-continuum method embedded with quantum simulations based on DFT to reach macroscopic length scales and an accelerated molecular dynamics scheme to reach macroscopic time scales in simulations of solid-fluid interfaces that are relevant to SCC. A hybrid MD and mesoscale lattice Boltzmann simulation algorithm is being designed to study fluid flow through cracks.

  14. Stress-Corrosion Interactions in Zr-Based Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Petre Flaviu Gostin

    2015-07-01

    Full Text Available Stress-corrosion interactions in materials may lead to early unpredictable catastrophic failure of structural parts, which can have dramatic effects. In Zr-based bulk metallic glasses, such interactions are particularly important as these have very high yield strength, limited ductility, and are relatively susceptible to localized corrosion in halide-containing aqueous environments. Relevant features of the mechanical and corrosion behavior of Zr-based bulk metallic glasses are described, and an account of knowledge regarding corrosion-deformation interactions gathered from ex situ experimental procedures is provided. Subsequently the literature on key phenomena including hydrogen damage, stress corrosion cracking, and corrosion fatigue is reviewed. Critical factors for such phenomena will be highlighted. The review also presents an outlook for the topic.

  15. Stress Corrosion Cracking of High-strength Drill Pipe in Sour Gas Well

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi; LI Jing; ZENG Dezhi; HU Junying; HOU Duo; ZHANG Liehui; SHI Taihe

    2014-01-01

    In high sour gas reservoir drilling process, it happens occasionally that high-strength drill pipe suffers brittle fracture failure due to stress corrosion cracking, and poses serious hazard to drilling safety. To solve this problem, this paper studied the stress corrosion cracking mechanism and influencing factors of high-strength drill pipe in sour environment with hydrogen permeation experiments and tensile tests. We simulated practical conditions in laboratory and evaluated the stress corrosion cracking performance of the high-strength drill pipe under conditions of high stress level. For the problems occurring in use of high-strength drill pipe on site, the paper proposed a technical measure for slower stress corrosion cracking.

  16. A Fracture Probability Competition Mechanism of Stress Corrosion Cracking

    Institute of Scientific and Technical Information of China (English)

    Yanliang HUANG

    2001-01-01

    The stress corrosion cracking (SCC) of austenitic stainless steel was studied via polarization,slow strain rate and scanning electron microscope (SEM) techniques. Many SCC mechanisms have been proposed in which hydrogen embrittlement and passive film rupture-repassivation theories are generally accepted, but they can hardly explain the SCC mechanism of austenitic stainless steel in acidic chloride solution adequately, because the steel is in active dissolution state and cathodic polarization can prevent it from occurring. Our experiment shows that the anodic current increases the creep rate and decreases the plastic strength of the material on single smooth specimen as well as at the SCC crack tip. The fractured surface was characterized as brittle cleavage, while the surface crack of smooth specimen was almost vertical to the tensile strength, which can confirm that the cracks were caused by tensile stresses. A fracture probability competition mechanism of SCC was proposed on the basis of the experimental results combined with the viewpoint of ductile-brittle fracture competition. When the anodic dissolution current is increased to a certain degree, the probability of fracture by tensile stress will exceed that by shear stress, and the brittle fracture will occur. The proposed SCC mechanism can not only explain the propagation of SCC cracks but can explain the crack initiation as well. The strain on the surface distributes unevenly when a smooth specimen is deformed, so does the anodic current distribution. The crack will initiate at a point where the anodic current density is large enough to cause the material at a specific point to fracture in brittle manner.

  17. Hydrogen embrittlement and stress corrosion cracking in metals

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Suk; Cheong, Yong Mu; Im, Kyung Soo

    2004-10-15

    The objective of this report is to elucidate the mechanism for hydrogen embrittlement (HE) and stress corrosion cracking (SCC) in metals. To this end, we investigate the common features between delayed hydride cracking (DHC) in zirconium alloys and HE in metals with no precipitation of hydrides including Fe base alloys, Nickel base alloys, Cu alloys and Al alloys. Surprisingly, as with the crack growth pattern for the DHC in zirconium alloy, the metals mentioned above show a discontinuous crack growth, striation lines and a strong dependence of yield strength when exposed to hydrogen internally and externally. This study, for the first time, analyzes the driving force for the HE in metals in viewpoints of Kim's DHC model that a driving force for the DHC in zirconium alloys is a supersaturated hydrogen concentration coming from a hysteresis of the terminal solid solubility of hydrogen, not by the stress gradient, As with the crack growing only along the hydride habit plane during the DHC in zirconium alloys, the metals exposed to hydrogen seem to have the crack growing by invoking the dislocation slip along the preferential planes as a result of some interactions of the dislocations with hydrogen. Therefore, it seems that the hydrogen plays a role in inducing the slip only on the preferential planes so as to cause a strain localization at the crack tip. Sulfur in metals is detrimental in causing a intergranular cracking due to a segregation of the hydrogens at the grain boundaries. In contrast, boron in excess of 500 ppm added to the Ni3Al intermetallic compound is found to be beneficial in suppressing the HE even though further details of the mechanism for the roles of boron and sulfur are required. Carbon, carbides precipitating semi-continuously along the grain boundaries and the CSL (coherent site lattice) boundaries is found to suppress the intergranular stress corrosion cracking (IGSCC) in Alloy 600. The higher the volume fraction of twin boundaries, the

  18. Stress corrosion cracking of stainless steels in NaCl solutions

    Science.gov (United States)

    Speidel, Markus O.

    1981-05-01

    The metallurgical influences on the stress corrosion resistance of many commercial stainless steels have been studied using the fracture mechanics approach. The straight-chromium ferritic stainless steels, two-phase ferritic-austenitic stainless steels and high-nickel solid solutions (like alloys 800 and 600) investigated are all fully resistant to stress corrosion cracking at stress intensity (K1) levels ≤ MN • m-3/2 in 22 pct NaCl solutions at 105 °C. Martensitic stainless steels, austenitic stainless steels and precipitation hardened superalloys, all with about 18 pct chromium, may be highly susceptible to stress corrosion cracking, depending on heat treatment and other alloying elements. Molybdenum additions improve the stress corrosion cracking resistance of austenitic stainless steels significantly. The fracture mechanics approach to stress corrosion testing of stainless steels yields results which are consistent with both the service experience and the results from testing with smooth specimens. In particular, the well known “Copson curve” is reproduced by plotting the stress corrosion threshold stress intensity (ATISCC) vs the nickel content of stainless steels with about 18 pct chromium.

  19. Computer Simulation of Intergranular Stress Corrosion Cracking via Hydrogen Embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.W.

    2000-04-01

    Computer simulation has been applied to the investigation of intergranular stress corrosion cracking in Ni-based alloys based on a hydrogen embrittlement mechanism. The simulation employs computational modules that address (a) transport and reactions of aqueous species giving rise to hydrogen generation at the liquid-metal interface, (b) solid state transport of hydrogen via intergranular and transgranular diffusion pathways, and (c) fracture due to the embrittlement of metallic bonds by hydrogen. A key focus of the computational model development has been the role of materials microstructure (precipitate particles and grain boundaries) on hydrogen transport and embrittlement. Simulation results reveal that intergranular fracture is enhanced as grain boundaries are weakened and that microstructures with grains elongated perpendicular to the stress axis are more susceptible to cracking. The presence of intergranular precipitates may be expected to either enhance or impede cracking depending on the relative distribution of hydrogen between the grain boundaries and the precipitate-matrix interfaces. Calculations of hydrogen outgassing and in gassing demonstrate a strong effect of charging method on the fracture behavior.

  20. The role of stress in self-ordered porous anodic oxide formation and corrosion of aluminum

    Science.gov (United States)

    Capraz, Omer Ozgur

    The phenomenon of plastic flow induced by electrochemical reactions near room temperature is significant in porous anodic oxide (PAO) films, charging of lithium batteries and stress-corrosion cracking (SCC). As this phenomenon is poorly understood, fundamental insight into flow from our work may provide useful information for these problems. In-situ monitoring of the stress state allows direct correlation between stress and the current or potential, thus providing fundamental insight into technologically important deformation and failure mechanisms induced by electrochemical reactions. A phase-shifting curvature interferometry was designed to investigate the stress generation mechanisms on different systems. Resolution of our curvature interferometry was found to be ten times more powerful than that obtained by state-of-art multiple deflectometry technique and the curvature interferometry helps to resolve the conflicting reports in the literature. During this work, formation of surface patterns during both aqueous corrosion of aluminum and formation of PAO films were investigated. Interestingly, for both cases, stress induced plastic flow controls the formation of surface patterns. Pore formation mechanisms during anodizing of the porous aluminum oxide films was investigated . PAO films are formed by the electrochemical oxidation of metals such as aluminum and titanium in a solution where oxide is moderately soluble. They have been used extensively to design numerous devices for optical, catalytic, and biological and energy related applications, due to their vertically aligned-geometry, high-specific surface area and tunable geometry by adjusting process variables. These structures have developed empirically, in the absence of understanding the process mechanism. Previous experimental studies of anodizing-induced stress have extensively focused on the measurement of average stress, however the measurement of stress evolution during anodizing does not provide

  1. Caustics in dark matter haloes

    CERN Document Server

    Mohayaee, R; Mohayaee, Roya; Colombi, Stephane; Fort, Bernard; Gavazzi, Raphael; Shandarin, Sergei; Touma, Jihad

    2005-01-01

    Cold dark matter haloes are populated by high-density structures with sharply-peaked profiles known as caustics which have not yet been resolved by 3-dimensional numerical simulations. Here, we derive semi-analytic expressions for the density profiles near caustics in haloes which form by self-similar accretions of dark matter with infinitesimal velocity dispersion. A simple rescaling shows that these profiles are universal: they are valid for all caustics and irrespective of physical parameters of the halo. We derive the maximum density of the caustics and show that it depends on the velocity dispersion and the caustic location. Finally, we demonstrate that there can be a significant contribution to the emission measure from dark matter particle annihilation in the caustics.

  2. The mechanism of stress-corrosion cracking in 7075 aluminum alloy

    Science.gov (United States)

    Jacobs, A. J.

    1970-01-01

    Various aspects of stress-corrosion cracking in 7075 aluminum alloy are discussed. A model is proposed in which the continuous anodic path along which the metal is preferentially attacked consists of two phases which alternate as anodes.

  3. Corrosion leaking of preheater weldment in alumina factories

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; CHEN Wen-mi; GONG Zhu-qing; LIU Hong-zhao

    2005-01-01

    Stress corrosion cracking (SCC) and anticorrosion measures of TU42C weld-joint were studied by constant load experiments and pickling experiments. The results show that in 40%(mass fraction) NaOH solution at 110 ℃, caustic SCC occurs in TU42C weld-joints at the applied potential of -1 020 mV(vs SCE) for 3 d while at the potential of -950 mV(vs SCE) for 10 d. All the cracks are intergranular. In the 10% sulfuric acid, the cracks have the most negative self-corrosion potential -432.5 mV(vs SCE) and are active to be further corroded by the acid. Because of the same corrosion behaviour as the lab weldment, preheater's cracking in alumina factories is attributed to the combining actions of previous caustic SCC in Bayer solutions and continuous acid corrosion by pickling with the addition of RD. The following measures are effective to prevent the corrosion failure of preheater, such as postweld heat treatment at 620 ℃ to relax the residual weld stress, addition of CC3 and L826 as the corrosion inhibitors to improve the pickling and cleaning by the high pressure water instead of by pickling.

  4. Computational modeling of the mechanism of hydrogen embrittlement (HE) and stress corrosion cracking (SCC) in metals

    Science.gov (United States)

    Cendales, E. D.; Orjuela, F. A.; Chamarraví, O.

    2016-02-01

    In this article theoretical models and some existing data sets were examined in order to model the two main causes (hydrogen embrittlement and corrosion-cracking under stress) of the called environmentally assisted cracking phenomenon (EAC). Additionally, a computer simulation of flat metal plate subject to mechanical stress and cracking due both to hydrogen embrittlement and corrosion was developed. The computational simulation was oriented to evaluate the effect on the stress-strain behavior, elongation percent and the crack growth rate of AISI SAE 1040 steel due to three corrosive enviroments (H2 @ 0.06MPa; HCl, pH=1.0; HCl, pH=2.5). From the computer simulation we conclude that cracking due to internal corrosion of the material near to the crack tip limits affects more the residual strength of the flat plate than hydrogen embrittlement and generates a failure condition almost imminent of the mechanical structural element.

  5. Synthetic sea water - An improved stress corrosion test medium for aluminum alloys

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1973-01-01

    A major problem in evaluating the stress corrosion cracking resistance of aluminum alloys by alternate immersion in 3.5 percent salt (NaCl) water is excessive pitting corrosion. Several methods were examined to eliminate this problem and to find an improved accelerated test medium. These included the addition of chromate inhibitors, surface treatment of specimens, and immersion in synthetic sea water. The results indicate that alternate immersion in synthetic sea water is a very promising stress corrosion test medium. Neither chromate inhibitors nor surface treatment (anodize and alodine) of the aluminum specimens improved the performance of alternate immersion in 3.5 percent salt water sufficiently to be classified as an effective stress corrosion test method.

  6. A study on the mechanism of stress corrosion cracking of duplex stainless steels in hot alkaline-sulfide solution

    Science.gov (United States)

    Chasse, Kevin Robert

    Duplex stainless steels (DSS) generally have superior strength and corrosion resistance as compared to most standard austenitic and ferritic stainless grades owing to a balanced microstructure of austenite and ferrite. As a result of having favorable properties, DSS have been selected for the construction of equipment in pulp and paper, chemical processing, nuclear, oil and gas as well as other industries. The use of DSS has been restricted in some cases because of stress corrosion cracking (SCC), which can initiate and grow in either the ferrite or austenite phase depending on the environment. Thorough understanding of SCC mechanisms of DSS in chloride- and hydrogen sulfide-containing solutions has been useful for material selection in many environments. However, understanding of SCC mechanisms of DSS in sulfide-containing caustic solutions is limited, which has restricted the capacity to optimize process and equipment design in pulp and paper environments. Process environments may contain different concentrations of hydroxide, sulfide, and chloride, altering corrosion and SCC susceptibility of each phase. Crack initiation and growth behavior will also change depending on the relative phase distribution and properties of austenite and ferrite. The role of microstructure and environment on the SCC of standard grade UNS S32205 and lean grade UNS S32101 in hot alkaline-sulfide solution were evaluated in this work using electrochemical, film characterization, mechanical testing, X-ray diffraction, and microscopy techniques. Microstructural aspects, which included residual stress state, phase distribution, phase ratio, and microhardness, were related to the propensity for SCC crack initiation in different simulated alkaline pulping liquors at 170 °C. Other grades of DSS and reference austenitic and superferritic grades of stainless steel were studied using exposure coupons for comparison to understand compositional effects and individual phase susceptibility

  7. Localized corrosion of LY12CZ under stress in chloride media

    Institute of Scientific and Technical Information of China (English)

    RAO Si-xian; ZHANG Zheng; ZHU Li-qun; ZHONG Qun-peng

    2006-01-01

    Electrochemical methods were applied to investigate the corrosion behaviour of LY12CZ under applied stress in 3% sodium chloride aqueous solution. The experimental results indicate that LY12CZ shows two breakdown potentials on its polarization curve: one is related to the dissolution of the intermetallic particles and the other is related to the cracking of oxidation film and the dissolution of the matrix. When the stress is applied, it varies both breakdown potentials and makes the intermetallic particles and matrix dissolute at lower potentials. The relationship between the variation of the two breakdown potentials and applied stress was summarized. At the same time the influence of stress on the pitting and intergranular corrosion sensitivity of LY12CZ was also investigated. From the results it can be concluded that the stress can significantly affect the localized corrosion behaviour of LY12CZ in 3% NaCl solution.

  8. Effects of laser heat treatment on the fracture morphologies of X80 pipeline steel welded joints by stress corrosion

    Institute of Scientific and Technical Information of China (English)

    De-jun Kong; Cun-dong Ye

    2014-01-01

    The surfaces of X80 pipeline steel welded joints were processed with a CO2 laser, and the effects of laser heat treatment (LHT) on H2S stress corrosion in the National Association of Corrosion Engineers (NACE) solution were analyzed by a slow strain rate test. The frac-ture morphologies and chemical components of corrosive products before and after LHT were analyzed by scanning electron microscopy and energy-dispersive spectroscopy, respectively, and the mechanism of LHT on stress corrosion cracking was discussed. Results showed that the fracture for welded joints was brittle in its original state, while it was transformed to a ductile fracture after LHT. The tendencies of hydro-gen-induced corrosion were reduced, and the stress corrosion sensitivity index decreased from 35.2%to 25.3%, indicating that the stress corrosion resistance of X80 pipeline steel welded joints has been improved by LHT.

  9. Residual strain change resulting from stress corrosion in Carrara marble

    Science.gov (United States)

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

    2016-04-01

    Residual stresses and strains have been shown to play a fundamental role in determining the elastic behavior of engineering materials, yet the effect of these strains on brittle and elastic behavior of rocks remains unclear. In order to evaluate the impact of stored elastic strains on fracture propagation in rock, we undertook a four-month-long three-point bending test on three large 1100 x 100 x 100 mm Carrara Marble samples. This test induced stable low stress conditions in which strains were concentrated at the tip of a saw cut and pre-cracked notch. A corrosive environment was created at the tip of the notch on two samples (M2 and M4) by dripping calcite saturated water (pH ~ 7.5-8). Sample M5 was loaded in the same way, but kept dry. Samples were unloaded prior to failure, and along with an additional non-loaded reference sample (M0), cored into cylindrical subsamples (ø = 50 mm, h = 100 mm) before being tested for changes in residual elastic strains at the SALSA neutron diffractometer at the Institute Laue-Langevin (ILL), Grenoble, France. Three diffraction peaks corresponding to crystallographic planes hkl (110), (104) and (006) were measured in all three spatial directions relative to the notch. Shifts in the diffraction peak position (d) with respect to a strain free state are indicative of intergranular strain, while changes in the width of the peak (FWHM) reflect changes in intragranular strain. We observe distinctly different patterns in residual and volumetric strains in hkℓ (104) and (006) for the dry M5 and wet tested samples (M2 and M4) indicating the presence of water changes the deformation mechanism, while (110) is strained in compression around 200 μstrain in all samples. A broadening of the diffraction peaks (006) and (110) in front of the crack tip is observed in M2 and M4, while M5 shows no changes in the peak width throughout the depth of the sample. We suggest water present at the crack tip increased the rate of corrosion, allowing a

  10. Standard practice for preparation and use of Bent-Beam stress-corrosion test specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This practice covers procedures for designing, preparing, and using bent-beam stress-corrosion specimens. 1.2 Different specimen configurations are given for use with different product forms, such as sheet or plate. This practice applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured (see Note 1). Stress calculations by this practice are not applicable to plastically stressed specimens. Note 1—It is the nature of these practices that only the applied stress can be calculated. Since stress-corrosion cracking is a function of the total stress, for critical applications and proper interpretation of results, the residual stress (before applying external stress) or the total elastic stress (after applying external stress) should be determined by appropriate nondestructive methods, such as X-ray diffraction (1). 1.3 Test procedures are given for stress-corrosion testing by ex...

  11. Ultrasonic inspection reliability for intergranular stress corrosion cracks

    Energy Technology Data Exchange (ETDEWEB)

    Heasler, P G; Taylor, T T; Spanner, J C; Doctor, S R; Deffenbaugh, J D [Pacific Northwest Lab., Richland, WA (USA)

    1990-07-01

    A pipe inspection round robin entitled Mini-Round Robin'' was conducted at Pacific Northwest Laboratory from May 1985 through October 1985. The research was sponsored by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research under a program entitled Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors.'' The Mini-Round Robin (MRR) measured the intergranular stress corrosion (GSC) crack detection and sizing capabilities of inservice inspection (ISI) inspectors that had passed the requirements of IEB 83-02 and the Electric Power Research Institute (EPRI) sizing training course. The MRR data base was compared with an earlier Pipe Inspection Round Robin (PIRR) that had measured the performance of inservice inspection prior to 1982. Comparison of the MRR and PIRR data bases indicates no significant change in the inspection capability for detecting IGSCC. Also, when comparing detection of long and short cracks, no difference in detection capability was measured. An improvement in the ability to differentiate between shallow and deeper IGSCC was found when the MRR sizing capability was compared with an earlier sizing round robin conducted by the EPRI. In addition to the pipe inspection round robin, a human factors study was conducted in conjunction with the Mini-Round Robin. The most important result of the human factors study is that the Relative Operating Characteristics (ROC) curves provide a better methodology for describing inspector performance than only probability of detection (POD) or single-point crack/no crack data. 6 refs., 55 figs., 18 tabs.

  12. The influence of molybdenum on stress corrosion in Ultra Low Carbon Steels with copper addition

    Directory of Open Access Journals (Sweden)

    M. Mazur

    2010-07-01

    Full Text Available The influence of molybdenum content on the process of stress corrosion of ultra-low carbon structural steels with the addition of copper HSLA (High Strength Low Alloy was analyzed. The study was conducted for steels after heat treatment consisting of quenching andfollowing tempering at 600°C and it was obtained microstructure of the tempered martensite laths with copper precipitates and the phaseLaves Fe2Mo type. It was found strong influence of Laves phase precipitate on the grain boundaries of retained austenite on rate anddevelopment of stress corrosion processes. The lowest corrosion resistance was obtained for W3 steel characterized by high contents ofmolybdenum (2.94% Mo which should be connected with the intensity precipitate processes of Fe2Mo phase. For steels W1 and W2which contents molybdenum equals 1.02% and 1.88%, respectively were obtained similar courses of corrosive cracking.

  13. Stress-Corrosion Cracking of Metallic Materials. Part III. Hydrogen Entry and Embrittlement in Steel

    Science.gov (United States)

    1975-04-01

    Strength Steels," Stress Corrosion Cracking in High-Strength Steels and in Titanium and Altuninum Alloys, Naval Rasearch Laboratory, Washington, D.C...to pickling solutions. In all of these examples, the sulfide, cyanide, etc., caused a hydrogen-related problem that would not have existed in their...desorption reaction. In studying the pickling of low-carbon steel in various strong acids, Hudson’ 4 measured the corrosion rate and amount of hydr-ogen

  14. Laser Peening for Mitigation of Stress Corrosion Cracking at Welds in Marine Aluminum

    Science.gov (United States)

    2011-06-01

    Second Reader: Joseph C. Farmer THIS PAGE INTENTIONALLY LEFT BLANK i REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden...Advisor Joseph C. Farmer Second Reader Knox Millsaps Chair, Department of Mechanical and Aerospace Engineering iv THIS PAGE...Cruisers, in Defense News2010. p. 4. [4] K. N. Tran, M. R. Hill, et al., Welding Journal, 85 (2006) 28. [5] M. G. Fontana , Stress Corrosion, in Corrosion

  15. Passive Films, Surface Structure and Stress Corrosion and Crevice Corrosion Susceptibility.

    Science.gov (United States)

    1983-11-01

    chelating inhibitor Introduction and its chemical nature can affect its performance in retarding coatinq failure. ACKNOWLEDGEMENTS The author would like to...distinguer entre 1’ apparition de rugosite’ et la croissance d’un film ou la dissolution, enfin d’etudier le processus de corrosion se produlsant sur des

  16. Assessing corrosion problems in photovoltaic cells via electrochemical stress testing

    Science.gov (United States)

    Shalaby, H.

    1985-01-01

    A series of accelerated electrochemical experiments to study the degradation properties of polyvinylbutyral-encapsulated silicon solar cells has been carried out. The cells' electrical performance with silk screen-silver and nickel-solder contacts was evaluated. The degradation mechanism was shown to be electrochemical corrosion of the cell contacts; metallization elements migrate into the encapsulating material, which acts as an ionic conducting medium. The corrosion products form a conductive path which results in a gradual loss of the insulation characteristics of the encapsulant. The precipitation of corrosion products in the encapsulant also contributes to its discoloration which in turn leads to a reduction in its transparency and the consequent optical loss. Delamination of the encapsulating layers could be attributed to electrochemical gas evolution reactions. The usefulness of the testing technique in qualitatively establishing a reliability difference between metallizations and antireflection coating types is demonstrated.

  17. Galvanic and stress corrosion of copper canisters in repository environment. A short review

    Energy Technology Data Exchange (ETDEWEB)

    Hermansson, H.P.; Koenig, M. [Studsvik Nuclear AB, Nykoeping (Sweden)

    2001-02-01

    The Swedish Nuclear Power Inspectorate, SKI, has studied different aspects of canister and copper corrosion as part of the general improvement of the knowledge base within the area. General and local corrosion has earlier been treated by experiments as well as by thermodynamic calculations. For completeness also galvanic and stress corrosion should be treated. The present work is a short review, intended to indicate areas needing further focus. The work consists of two parts, the first of which contains a judgement of statements concerning risk of galvanic corrosion of copper in the repository. The second part concerns threshold values for the stress intensity factor of stress corrosion in copper. A suggestion is given on how such values possibly could be measured for copper at repository conditions. In early investigations by SKB, galvanic corrosion is not mentioned or at least not treated. In later works it is treated but often in a theoretical way without indications of any further treatment or investigation. Several pieces of work indicate that further investigations are required to ensure that different types of corrosion, like galvanic, cannot occur in the repository environment. There are for example effects of grain size, grain boundary conditions, impurities and other factors that could influence the appearance of galvanic corrosion that are not treated. Those factors have to be considered to be completely sure that galvanic corrosion and related effects does not occur for the actual canister in the specific environment of the repository. The circumstances are so specific, that a rather general discussion indicating that galvanic corrosion is not probable just is not enough. Experiments should also be performed for verification. It is concluded that the following specific areas, amongst others, could benefit from further consideration. Galvanic corrosion of unbreached copper by inhomogeneities in the environment and in the copper metal should be addressed

  18. Stress Corrosion Evaluation of Various Metallic Materials for the International Space Station Water Recycling System

    Science.gov (United States)

    Torres, P. D.

    2015-01-01

    A stress corrosion evaluation was performed on Inconel 625, Hastelloy C276, titanium commercially pure (TiCP), Ti-6Al-4V, Ti-6Al-4V extra low interstitial, and Cronidur 30 steel as a consequence of a change in formulation of the pretreatment for processing the urine in the International Space Station Environmental Control and Life Support System Urine Processing Assembly from a sulfuric acid-based to a phosphoric acid-based solution. The first five listed were found resistant to stress corrosion in the pretreatment and brine. However, some of the Cronidur 30 specimens experienced reduction in load-carrying ability.

  19. Causticizing for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Scott Sinquefeld; James Cantrell; Xiaoyan Zeng; Alan Ball; Jeff Empie

    2009-01-07

    The cost-benefit outlook of black liquor gasification (BLG) could be greatly improved if the smelt causticization step could be achieved in situ during the gasification step. Or, at a minimum, the increase in causticizing load associated with BLG could be mitigated. A number of chemistries have been proven successful during black liquor combustion. In this project, three in situ causticizing processes (titanate, manganate, and borate) were evaluated under conditions suitable for high temperature entrained flow BLG, and low temperature steam reforming of black liquor. The evaluation included both thermodynamic modeling and lab experimentation. Titanate and manganate were tested for complete direct causticizing (to thus eliminate the lime cycle), and borates were evaluated for partial causticizing (to mitigate the load increase associated with BLG). Criteria included high carbonate conversion, corresponding hydroxide recovery upon hydrolysis, non process element (NPE) removal, and economics. Of the six cases (three chemistries at two BLG conditions), only two were found to be industrially viable: titanates for complete causticizing during high temperature BLG, and borates for partial causticizing during high temperature BLG. These two cases were evaluated for integration into a gasification-based recovery island. The Larsen [28] BLG cost-benefit study was used as a reference case for economic forecasting (i.e. a 1500 tpd pulp mill using BLG and upgrading the lime cycle). By comparison, using the titanate direct causticizing process yielded a net present value (NPV) of $25M over the NPV of BLG with conventional lime cycle. Using the existing lime cycle plus borate autocausticizing for extra capacity yielded a NPV of $16M.

  20. 49 CFR 192.929 - What are the requirements for using Direct Assessment for Stress Corrosion Cracking (SCCDA)?

    Science.gov (United States)

    2010-10-01

    ... requirements for using Direct Assessment for Stress Corrosion Cracking (SCCDA)? (a) Definition. Stress..., appendix A3, and remediate the threat in accordance with ASME/ANSI B31.8S, appendix A3, section A3.4....

  1. Caustic ingestion-a forensic overview.

    Science.gov (United States)

    Byard, Roger W

    2015-05-01

    The ingestion of corrosive substances may produce severe burns to the upper aerodigestive tract and stomach, particularly if the pH is greater than 12 or less than two. There is a biphasic age grouping with adult cases most often involving self-harm and pediatric cases accidental ingestion. Three cases are reported to demonstrate characteristic features following the ingestion of potassium hydroxide, glacial acetic acid and Lysol(®) , respectively. All deaths were due to the effects of caustic burns to the upper aerodigestive tract, esophagus and stomach with perforation and/or hemorrhage. The extent of injuries in these cases depends on the nature, amount, and concentration of the agent and on the exposure time. A point to note at autopsy is that tissue damage may also occur from postmortem exposure. Typical injuries involve perioral, limb, and trunk burns, with extensive aerodigestive liquefactive/coagulative necrosis causing hemorrhage and perforation.

  2. Corrosion Behavior of the Stressed Sensitized Austenitic Stainless Steels of High Nitrogen Content in Seawater

    Directory of Open Access Journals (Sweden)

    A. Almubarak

    2013-01-01

    Full Text Available The purpose of this paper is to study the effect of high nitrogen content on corrosion behavior of austenitic stainless steels in seawater under severe conditions such as tensile stresses and existence of sensitization in the structure. A constant tensile stress has been applied to sensitized specimens types 304, 316L, 304LN, 304NH, and 316NH stainless steels. Microstructure investigation revealed various degrees of stress corrosion cracking. SCC was severe in type 304, moderate in types 316L and 304LN, and very slight in types 304NH and 316NH. The electrochemical polarization curves showed an obvious second current peak for the sensitized alloys which indicated the existence of second phase in the structure and the presence of intergranular stress corrosion cracking. EPR test provided a rapid and efficient nondestructive testing method for showing passivity, degree of sensitization and determining IGSCC for stainless steels in seawater. A significant conclusion was obtained that austenitic stainless steels of high nitrogen content corrode at a much slower rate increase pitting resistance and offer an excellent resistance to stress corrosion cracking in seawater.

  3. Ingestion of Caustic Substances in Adults: A Review Article

    Directory of Open Access Journals (Sweden)

    Andon Chibishev

    2013-02-01

    Full Text Available Background: Ingestion of caustic agents can cause serious damages of the upper gastrointestinal tract and in some cases this kind of poisoning may have fatal outcomes. Acute caustic intoxications are one of the main problems in the modern clinical toxicology since they mainly affect young people with psychic disorders, suicidal intent, and alcohol addiction. Text: In diagnostic evaluation of this kind of poisoning, different procedures are used. Today’s golden standard for determination of the grade and extent of the lesion is esophagogastroduodenoscopy (EGD performed in the first 12-24 hours following corrosive ingestion. In some patients, some late complications, such as esophageal stenosis and gastric stenosis, which are the most common, as well as carcinoma of the upper gastrointestinal tract, which is rarely seen, can be detected. Acute caustic poisonings are treated with specific kinds of protocols. According to them, first, an attempt is made to neutralize the poison. Combinations of antibiotics, anti-secretory drugs, and collagen synthesis inhibitors are used. As a support therapy, nutritional liquids can be utilized, and in the most unmanageable cases, esophageal dilatation, stent placement and surgery are used. Conclusion: In the future, caustic poisonings will remain a serious socio-medical issue, due to the difficult clinical presentation, expensive diagnostic protocol, extended hospitalization, and possible permanent disability.

  4. Effects of crystal defects on stress-corrosion susceptibility in aluminum alloy 7075

    Science.gov (United States)

    Bentle, G. G.; Jacobs, A. J.

    1970-01-01

    Point defects were introduced into specimens of three heat-treated tempers of alloy 7075 by neutron irradiation. Continuous ultrasonic monitoring allowed crack growth to be observed. Effects on stress-corrosion susceptibility, elongation, hardness, and yield strength are noted and compared for the three tempers.

  5. Stress-Corrosion Cracking in High Strength Steels and in Titanium and Aluminum Alloys

    Science.gov (United States)

    1972-01-01

    importance that the newcomer might wonder why the question is not settled almost as the first order of business . The reason is that to prove the... Agricola and J. T. Snyder, "Stress Corrosion of Explosively Deformed High-Strength Alloys," Metals Eng. Quart. 7 (No. 3), 59 (1967). 138. P. N. Orava

  6. Stress Corrosion Cracking of an Austenitic Stainless Steel in Nitrite-Containing Chloride Solutions

    Directory of Open Access Journals (Sweden)

    R. K. Singh Raman

    2014-12-01

    Full Text Available This article describes the susceptibility of 316L stainless steel to stress corrosion cracking (SCC in a nitrite-containing chloride solution. Slow strain rate testing (SSRT in 30 wt. % MgCl2 solution established SCC susceptibility, as evidenced by post-SSRT fractography. Addition of nitrite to the chloride solution, which is reported to have inhibitive influence on corrosion of stainless steels, was found to increase SCC susceptibility. The susceptibility was also found to increase with nitrite concentration. This behaviour is explained on the basis of the passivation and pitting characteristics of 316L steel in chloride solution.

  7. Cluster analysis of stress corrosion mechanisms for steel wires used in bridge cables through acoustic emission particle swarm optimization.

    Science.gov (United States)

    Li, Dongsheng; Yang, Wei; Zhang, Wenyao

    2017-01-18

    Stress corrosion is the major failure type of bridge cable damage. The acoustic emission (AE) technique was applied to monitor the stress corrosion process of steel wires used in bridge cable structures. The damage evolution of stress corrosion in bridge cables was obtained according to the AE characteristic parameter figure. A particle swarm optimization cluster method was developed to determine the relationship between the AE signal and stress corrosion mechanisms. Results indicate that the main AE sources of stress corrosion in bridge cables included four types: passive film breakdown and detachment of the corrosion product, crack initiation, crack extension, and cable fracture. By analyzing different types of clustering data, the mean value of each damage pattern's AE characteristic parameters was determined. Different corrosion damage source AE waveforms and the peak frequency were extracted. AE particle swarm optimization cluster analysis based on principal component analysis was also proposed. This method can completely distinguish the four types of damage sources and simplifies the determination of the evolution process of corrosion damage and broken wire signals.

  8. Pitting Corrosion of 316L Stainless Steel under Low Stress below Yield Strength

    Institute of Scientific and Technical Information of China (English)

    L(U) Shengjie; CHENG Xuequn; LI Xiaogang

    2012-01-01

    Pitting corrosion of 316L stainless steel (316L SS) under various stress was studied by potentiodynamic polarization,electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) analysis in 3.5% NaCl solution.The results of polarization curves show that,with the increase of the stress,the pitting potentials and the passive current density markedly decrease firstly (180 MPa),and then increase greatly (200 MPa).The corresponding surface morphologies of the samples after the polarization test well correspond to the results.Mott-Schottky analysis proved the least Cl- adsorbed to the surface of passive film with more positive flat potential,indicating that a moderate stress could increase the pitting corrosion resistance of 316L SS in 3.5% NaCl solution.

  9. Evaluation of the stress corrosion cracking resistance of several high strength low alloy steels

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1980-01-01

    The stress corrosion cracking resistance was studied for high strength alloy steels 4130, 4340, for H-11 at selected strength levels, and for D6AC and HY140 at a single strength. Round tensile and C-ring type specimens were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, salt spray, the atmosphere at Marshall Space Flight Center, and the seacoast at Kennedy Space Center. Under the test conditions, 4130 and 4340 steels heat treated to a tensile strength of 1240 MPa (180 ksi), H-11 and D6AC heat treated to a tensile strength of 1450 MPa (210 ksi), and HY140 (1020 MPa, 148 ksi) are resistant to stress corrosion cracking because failures were not encountered at stress levels up to 75 percent of their yield strengths. A maximum exposure period of one month for alternate immersion in salt water or salt spray and three months for seacoast is indicated for alloy steel to avoid false indications of stress corrosion cracking because of failure resulting from severe pitting.

  10. Effect of Stress on Corrosion at Crack Tip on Pipeline Steel in a Near-Neutral pH Solution

    Science.gov (United States)

    Yang, Yao; Cheng, Y. Frank

    2016-11-01

    In this work, the local corrosion at crack tip on an API 5L X46 pipeline steel specimens was investigated under various applied loads in a near-neutral pH solution. Electrochemical measurements, including potentiodynamic polarization and electrochemical impedance spectroscopy, combined with micro-electrochemical technique and surface characterization, were conducted to investigate the effect of stress on local anodic solution of the steel at the crack tip. The stress corrosion cracking of the steel was dominated by an anodic dissolution mechanism, while the effect of hydrogen was negligible. The applied load (stress) increased the corrosion rate at the crack tip, contributing to crack propagation. The deposit of corrosion products at the crack tip could protect somewhat from further corrosion. At sufficiently large applied loads such as 740 N in the work, it was possible to generate separated cathode and anode, further accelerating the crack growth.

  11. Effect of Stress on Corrosion at Crack Tip on Pipeline Steel in a Near-Neutral pH Solution

    Science.gov (United States)

    Yang, Yao; Cheng, Y. Frank

    2016-10-01

    In this work, the local corrosion at crack tip on an API 5L X46 pipeline steel specimens was investigated under various applied loads in a near-neutral pH solution. Electrochemical measurements, including potentiodynamic polarization and electrochemical impedance spectroscopy, combined with micro-electrochemical technique and surface characterization, were conducted to investigate the effect of stress on local anodic solution of the steel at the crack tip. The stress corrosion cracking of the steel was dominated by an anodic dissolution mechanism, while the effect of hydrogen was negligible. The applied load (stress) increased the corrosion rate at the crack tip, contributing to crack propagation. The deposit of corrosion products at the crack tip could protect somewhat from further corrosion. At sufficiently large applied loads such as 740 N in the work, it was possible to generate separated cathode and anode, further accelerating the crack growth.

  12. Stress corrosion cracking of AISI 321 stainless steel in acidic chloride solution

    Indian Academy of Sciences (India)

    Yanliang Huang

    2002-02-01

    The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic chloride solution was studied by slow strain rate (SSR) technique and fracture mechanics method. The fractured surface was characterized by cleavage fracture. In order to clarify the SCC mechanism, the effects of inhibitor KI on SCC behaviour were also included in this paper. A study showed that the inhibition effects of KI on SCC were mainly attributed to the anodic reaction of the corrosion process. The results of strain distribution in front of the crack tip of the fatigue pre-cracked plate specimens in air, in the blank solution (acidic chloride solution without inhibitor KI) and in the solution added with KI measured by speckle interferometry (SPI) support the unified mechanism of SCC and corrosion fatigue cracking (CFC).

  13. Role of pH on the stress corrosion cracking of titanium alloys

    Science.gov (United States)

    Khokhar, M. I.; Beck, F. H.; Fontana, M. G.

    1973-01-01

    Stress corrosion cracking (SCC) experiments were conducted on Ti-8-1-1 wire specimens in hydrochloric and sulfuric acids of variable pH in order to determine the effect of pH on the susceptibility to cracking. The alloy exhibited increasing susceptibility with decreasing pH. By varying the applied potential, it was observed that susceptibility zones exist both in the cathodic and the anodic ranges. In the cathodic range, susceptibility also increased with decreasing applied potential. Corrosion potential-time data in hydrochloric acid (pH 1.7) and sulfuric acid (pH 1.7) indicate that chloride ions lower the corrosion potential of the specimen which, in turn, increases the susceptibility.

  14. High-Performance Laser Peening for Effective Mitigation of Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Hackel, L; Hao-Lin, C; Wong, F; Hill, M

    2002-10-02

    Stress corrosion cracking (SCC) in the Yucca Mountain waste package closure welds is believed to be the greatest threat to long-term containment. Use of stress mitigation to eliminate tensile stresses resulting from welding can prevent SCC. A laser technology with sufficient average power to achieve high throughput has been developed and commercially deployed with high peak power and sufficiently high average power to be an effective laser peening system. An appropriately applied version of this process could be applied to eliminate SCC in the waste package closure welds.

  15. Effect of surface stress states on the corrosion behavior of alloy 690

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Mo; Shim, Hee Sang; Seo, Myung Ji; Hur, Do Haeng [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The test environment simulated the primary water chemistry in PWRs. Dissolved oxygen (DO), dissolved hydrogen (DH), pH and conductivity were monitored at room temperature using sensors manufactured by Orbisphere and Mettler Toledo. The temperature and pressure were maintained at 330 .deg. C and 150 bars during the corrosion test. The condition of the test solution was lithium (LiOH) 2 ppm and boron (H3BO4) 1,200 ppm, DH 35 cc/kg (STP) and less than 5 ppb DO. The flow rate of the loop system was 3.8 L/hour. Corrosion tests were conducted for 500 hours. The corrosion release rate was evaluated by a gravimetric analysis method using a two-step alkaline permanganate-ammonium citrate (AP/AC) descaling process. Compressive residual stress is induced by shot peening treatment but its value reveals some different trend between the shot peening intensity on the surface of Alloy 690 TT. A higher shot peening intensity causes a reduction in the corrosion rate and it is considered that the compressive residual stress beneath the surface layer suppresses the metal ion transfer in an alloy matrix.

  16. Simulated Service and Stress Corrosion Cracking Testing for Friction Stir Welded Spun Formed Domes

    Science.gov (United States)

    Stewart, Thomas J.; Torres, Pablo D.; Caratus, Andrei A.; Curreri, Peter A.

    2010-01-01

    Simulated service testing (SST) development was required to help qualify a new 2195 aluminum lithium (Al-Li) alloy spin forming dome fabrication process for the National Aeronautics and Space Administration (NASA) Exploration Development Technology Program. The application for the technology is to produce high strength low weight tank components for NASA s next generation launch vehicles. Since plate material is not currently manufactured large enough to fabricate these domes, two plates are joined by means of friction stir welding. The plates are then pre-contour machined to near final thicknesses allowing for a thicker weld land and anticipating the level of stretch induced by the spin forming process. The welded plates are then placed in a spin forming tool and hot stretched using a trace method producing incremental contours. Finally the dome receives a room temperature contour stretch to final dimensions, heat treatment, quenching, and artificial aging to emulate a T-8 condition of temper. Stress corrosion cracking (SCC) tests were also performed by alternate immersion in a sodium chloride (NaCl) solution using the typical double beam assembly and with 4-point loaded specimens and use of bent-beam stress-corrosion test specimens under alternate immersion conditions. In addition, experiments were conducted to determine the threshold stress intensity factor for SCC (K(sub ISCC)) which to our knowledge has not been determined previously for Al-Li 2195 alloy. The successful simulated service and stress corrosion testing helped to provide confidence to continue to Ares 1 scale dome fabrication

  17. Analytical assessment for stress corrosion fatigue of CANDU fuel elements under load following conditions

    Energy Technology Data Exchange (ETDEWEB)

    Horhoianu, Grigore; Ionescu, Drags; Pauna, Eduard [Institute for Nuclear Research, Pitesti (Romania). Nuclear Fuel Engineering Lab.

    2012-03-15

    When nuclear power reactors are operated in a load following (LF) mode, the nuclear fuel may be subjected to step changes in power on weekly, daily, or even hourly basis, depending on the grid's needs. Two load following tests performed in TRIGA Research Reactor of Institute for Nuclear Research (INR) Pitesti were simulated with finite elements computer codes in order to evaluate Stress Corrosion Fatigue (SCF) of the sheath arising from expansion and contraction of the pellets in the corrosive environment. The 3D finite element analyses show that the cyclic strains give highly multiaxial stresses in the sheath at ridge region. This paper summarizes the results of the analytical assessment for SCF and their relation to CANDU fuel performance in LF tests conditions. (orig.)

  18. The stress corrosion susceptibility of a quenched and tempered 12 pct crmov martensitic stainless steel

    Science.gov (United States)

    Doig, P.; Chastell, D. J.; Flewitt, P. E. J.

    1982-05-01

    The stress corrosion susceptibility of a martensitic 12 pct Cr 1 pct MoV stainless steel in alkaline chloride solution has been measured as a function of tempering heat treatment. The microstructures produced during tempering have been characterized by transmission electron microscopy and related to measured hardness values. In addition, scanning transmission electron microscopy combined with energy dispersive X-ray microanalysis has allowed the distribution of alloying elements within the microstructure to be examined. Electron energy loss spectroscopy was used to establish fully precipitate compositions, and the microanalysis results have been explained in terms of a diffusion controlled growth of grain boundary precipitates. The overall stress corrosion cracking susceptibility has been correlated with the development of chromium solute depletion profiles about prior austenite grain boundaries.

  19. Surface Chemistry and Structural Effects in the Stress Corrosion of Glass and Ceramic Materials

    Science.gov (United States)

    1988-09-15

    the strength and fatigue characteristics of ZBLAN (zirconium barium-lanthanum-aluminum-sodium fluoride) optical glass fiber obtained from British...Surface Chemistry and Structural Effects in the Stress Corrosion of Glass and Ceramic Materlals 12. PERSONAL AUTHOR(S) Carlo G. Pantano 13a. TYPE OF...fluorozirconate glasses . °. DTICS ELEC T E DEC 09 I 20. DISTRIBUTION/ AVAILABILITY OF ABSTRACT 21.-A% RACT SECURITY CLASSIFICATION [BUNCLASSIFIED/UNLIMITED

  20. Assessment study of the stresses induced by corrosion in the Advanced Cold Process Canister

    Energy Technology Data Exchange (ETDEWEB)

    Hoch, A.R.; Sharland, S.M. [Chemical Studies Department, Radwaste Disposal Division, AEA Decommissioning and Radwaste, Harwell Laboratory, Oxfordshire (United Kingdom)

    1993-10-01

    The Advanced Cold Process Canister (ACPC) is a concept for the encapsulation of spent nuclear fuel for geological disposal. The basic design of the ACPC consists of an outer oxygen free copper overpack covering a carbon steel inner container. In this report the stresses exerted on the copper overpack as a result of an early failure of the canister and the subsequent corrosion of the steel are calculated. 4 figs, 8 refs, 2 tabs.

  1. The Effect of Sensitization on the Stress Corrosion Cracking of Aluminum Alloy 5456

    Science.gov (United States)

    2012-06-01

    Reader: Joseph C. Farmer THIS PAGE INTENTIONALLY LEFT BLANK i REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for...Thesis Advisor Joseph C. Farmer Second Reader Knox Millsaps Chair, Department of Mechanical and Aerospace Engineering iv THIS PAGE...NavigationMenu/TheIndustry/IndustryStandar ds/TheAluminumIndustryContinuesEffortstoSupporttheMar.pdf [3] M. G. Fontana , "Stress corrosion," in

  2. Heat treatment of NiCrFe alloy 600 to optimize resistance to intergranular stress corrosion

    Science.gov (United States)

    Steeves, A.F.; Bibb, A.E.

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprises heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cooling the alloy body, and heating the cooled body to a temperature between 1100 to 1500/sup 0/F for about 1 to 30 hours.

  3. Hydrogen-related stress corrosion cracking in line pipe steel

    DEFF Research Database (Denmark)

    Nielsen, Lars Vendelbo

    1997-01-01

    A correlation between hydrogen concentration (C0) and the critical stress intensity factor for propagation of hydrogen-related cracks has been established by fracture mechanical testing of CT-specimens for the heat affected zone of an X-70 pipeline steel. This has been compared with field measure...

  4. Fundamental aspects of stress corrosion cracking of copper relevant to the Swedish deep geologic repository concept

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskaran, Ganesh; Carcea, Anatolie; Ulaganathan, Jagan; Wang, Shengchun; Huang, Yin; Newman, Roger C. [Dept. of Chemical Engineering and Applied Chemistry, Univ. of Toronto, Toronto (Canada)

    2013-03-15

    Phosphorus-doped oxygen-free copper will be used as the outer barrier in canisters that will contain spent nuclear fuel in the proposed Swedish underground repository. The possibility of stress corrosion cracking (SCC) is a concern, in view of isolated reports of cracking or intergranular corrosion of pure copper in sulfide solutions. This concern was addressed in the present work using copper tensile specimens provided by SKB. Methods included slow strain rate testing, constant strain tensile testing, electrochemical and surface analytical studies of corrosion products, and electron backscatter diffraction analysis of grain orientation effects on corrosion. The base solutions were prepared from NaCl or synthetic sea water with addition of varying amounts of sodium sulfide at room temperature and 80 degree Celsius. No SCC was found in any of the testing, for a range of sulfide concentrations from 5-50 mM at room temperature or 8 C, including tests where small anodic or cathodic potential displacements were applied from the open-circuit (corrosion) potential. Neither was SCC found in constant-strain immersion testing with very large strain. The Cu2S corrosion product is generally very coarse, fragile, and easily spalled off in severe corrosion environments, i.e. high sulfide concentration, high temperature, less perfect de aeration, etc. But it could also consist of very fine grains, relatively compact and adherent, on particular grain orientations when it was formed on an electro polished surface in a very well-deaerated solution. These orientations have not yet been identified statistically, although some preference for thin, adherent films was noted on orientations close to (100). The notion that the corrosion reaction is always controlled by inward aqueous-phase diffusion of sulfide may thus not be unconditionally correct for this range of sulfide concentrations; however it is hard to distinguish the role of diffusion within pores in the film. In the actual

  5. Accelerated Stress Corrosion Crack Initiation of Alloys 600 and 690 in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Was, Gary S.

    2017-01-01

    The objective of this study is to determine whether stress corrosion crack initiation of Alloys 600 and 690 occurs by the same mechanism in subcritical and supercritical water. Tensile bars of Alloys 690 and 600 were strained in constant extension rate tensile experiments in hydrogenated subcritical and supercritical water from 593 K to 723 K (320 °C to 450 °C), and the crack initiation behavior was characterized by high-resolution electron microscopy. Intergranular cracking was observed across the entire temperature range, and the morphology, structure, composition, and temperature dependence of initiated cracks in Alloy 690 were consistent between hydrogenated subcritical and supercritical water. Crack initiation of Alloy 600 followed an Arrhenius relationship and did not exhibit a discontinuity or change in slope after crossing the critical temperature. The measured activation energy was 121 ± 13 kJ/mol. Stress corrosion crack initiation in Alloy 690 was fit with a single activation energy of 92 ± 12 kJ/mol across the entire temperature range. Cracks were observed to propagate along grain boundaries adjacent to chromium-depleted metal, with Cr2O3 observed ahead of crack tips. All measures of the SCC behavior indicate that the mechanism for stress corrosion crack initiation of Alloy 600 and Alloy 690 is consistent between hydrogenated subcritical and supercritical water.

  6. Analysis of stress corrosion cracking in alloy 718 following commercial reactor exposure

    Science.gov (United States)

    Leonard, Keith J.; Gussev, Maxim N.; Stevens, Jacqueline N.; Busby, Jeremy T.

    2015-11-01

    Alloy 718 is generally considered a highly corrosion-resistant material but can still be susceptible to stress corrosion cracking (SCC). The combination of factors leading to SCC susceptibility in the alloy is not always clear enough. In the present work, alloy 718 leaf spring (LS) materials that suffered stress corrosion damage during two 24-month cycles in pressurized water reactor service, operated to >45 MWd/mtU burn-up, was investigated. Compared to archival samples fabricated through the same processing conditions, little microstructural and property changes occurred in the material with in-service irradiation, contrary to high dose rate laboratory-based experiments reported in literature. Though the lack of delta phase formation along grain boundaries would suggest a more SCC resistant microstructure, grain boundary cracking in the material was extensive. Crack propagation routes were explored through focused ion beam milling of specimens near the crack tip for transmission electron microscopy as well as in polished plan view and cross-sectional samples for electron backscatter diffraction analysis. It has been shown in this study that cracks propagated mainly along random high-angle grain boundaries, with the material around cracks displaying a high local density of dislocations. The slip lines were produced through the local deformation of the leaf spring material above their yield strength. The cause for local SCC appears to be related to oxidation of both slip lines and grain boundaries, which under the high in-service stresses resulted in crack development in the material.

  7. Accelerated Stress Corrosion Crack Initiation of Alloys 600 and 690 in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Was, Gary S.

    2017-04-01

    The objective of this study is to determine whether stress corrosion crack initiation of Alloys 600 and 690 occurs by the same mechanism in subcritical and supercritical water. Tensile bars of Alloys 690 and 600 were strained in constant extension rate tensile experiments in hydrogenated subcritical and supercritical water from 593 K to 723 K (320 °C to 450 °C), and the crack initiation behavior was characterized by high-resolution electron microscopy. Intergranular cracking was observed across the entire temperature range, and the morphology, structure, composition, and temperature dependence of initiated cracks in Alloy 690 were consistent between hydrogenated subcritical and supercritical water. Crack initiation of Alloy 600 followed an Arrhenius relationship and did not exhibit a discontinuity or change in slope after crossing the critical temperature. The measured activation energy was 121 ± 13 kJ/mol. Stress corrosion crack initiation in Alloy 690 was fit with a single activation energy of 92 ± 12 kJ/mol across the entire temperature range. Cracks were observed to propagate along grain boundaries adjacent to chromium-depleted metal, with Cr2O3 observed ahead of crack tips. All measures of the SCC behavior indicate that the mechanism for stress corrosion crack initiation of Alloy 600 and Alloy 690 is consistent between hydrogenated subcritical and supercritical water.

  8. SRNL SHELF LIFE STUDIES - SCC STUDIES AT ROOM TEMPERTURE [stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Duffey, J.

    2014-11-12

    Phase II, Series 2 corrosion testing performed by the Savannah River National Laboratory (SRNL) for the Department of Energy 3013 container has been completed. The corrosion tests are part of an integrated plan conducted jointly by Los Alamos National Laboratory and the Savannah River Site. SRNL was responsible for conducting corrosion studies in small-scale vessels to address the influence of salt composition, water loading, and type of oxide/salt contact on the relative humidity inside a 3013 container and on the resulting corrosion of Type 304L and 316L stainless steel (304L and 316L). This testing was conducted in two phases: Phase I evaluated a broad spectrum of salt compositions and initial water loadings on the salt mixtures exposed to 304L and 316L and the resulting corrosion; Phase II evaluated the corrosion of 304L at specific water loadings and a single salt composition. During Phase I testing at high initial moisture levels (0.35 to 1.24 wt%)a, the roomtemperature corrosion of 304L exposed to a series of plutonium oxide/chloride salt mixtures ranged from superficial staining to pitting and stress corrosion cracking (SCC). 304L teardrop coupons that exhibited SCC were directly exposed to a mixture composed of 98 wt % PuO2, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl2. Cracking was not observed in a 316L teardrop coupon. Pitting was also observed in this environment for both 304L and 316L with depths ranging from 20 to 100 μm. Neither pitting nor SCC was observed in mixtures with a greater chloride salt concentration (5 and 28 wt%). These results demonstrated that for a corrosive solution to form a balance existed between the water loading and the salt chloride concentration. This chloride solution results from the interaction of loaded water with the hydrating CaCl2 salt. In Phase II, Series 1 tests, the SCC results were shown to be reproducible with cracking occurring in as little as 85 days. The approximate 0.5 wt% moisture level was found to

  9. Research on mechanisms of stress corrosion cracking in Zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Knorr, D.B.; Pelloux, R.M.

    1981-06-01

    The results of internal gas pressurization tests, primarily at 320/sup 0/C, on cladding tubes from two suppliers, Supplier A and Supplier B, are presented. The two lots show a substantial difference in iodine SCC susceptibility so a test matrix is used to resolve the relative contributions of surface condition, residual stress, and texture. Additional tests with constant deflection split-ring specimens and with unstressed cladding segments are used to understand crack initiation and the early crack growth stages of SCC. The difference in SCC susceptibility is due to crystallographic texture. Other variables such as surface finish, stress relief temperature, and residual stress have little or no effect. Mechanical properties, crack initiation, and crack propagation all depend on texture. Both initiation and propagation features are analyzed by scanning electron microscopy. A mechanism for crack initiation consistent with most observations in this study and with the work of other investigators is proposed. At 320/sup 0/C, lifetime is crack initiation limited while several tests at 390/sup 0/C indicate that lifetime is less initiation limited at higher temperature. 31 figures, 9 tables.

  10. Effect of titanium nitride/titanium coatings on the stress corrosion of nickel-titanium orthodontic archwires in artificial saliva

    Science.gov (United States)

    Liu, Jia-Kuang; Liu, I.-Hua; Liu, Cheng; Chang, Chen-Jung; Kung, Kuan-Chen; Liu, Yen-Ting; Lee, Tzer-Min; Jou, Jin-Long

    2014-10-01

    The purpose of this investigation was to develop titanium nitride (TiN)/titanium (Ti) coating on orthodontic nickel-titanium (NiTi) wires and to study the stress corrosion of specimens in vitro, simulating the intra-oral environment in as realistic a manner as possible. TiN/Ti coatings were formed on orthodontic NiTi wires by physical vapor deposition (PVD). The characteristics of untreated and TiN/Ti-coated NiTi wires were evaluated by measurement of corrosion potential (Ecorr), corrosion current densities (Icorr), breakdown potential (Eb), and surface morphology in artificial saliva with different pH and three-point bending conditions. From the potentiodynamic polarization and SEM results, the untreated NiTi wires showed localized corrosion compared with the uniform corrosion observed in the TiN/Ti-coated specimen under both unstressed and stressed conditions. The bending stress influenced the corrosion current density and breakdown potential of untreated specimens at both pH 2 and pH 5.3. Although the bending stress influenced the corrosion current of the TiN/Ti-coated specimens, stable and passive corrosion behavior of the stressed specimen was observed even at 2.0 V (Ag/AgCl). It should be noted that the surface properties of the NiTi alloy could determine clinical performance. For orthodontic application, the mechanical damage destroys the protective oxide film of NiTi; however, the self-repairing capacity of the passive film of NiTi alloys is inferior to Ti in chloride-containing solutions. In this study, the TiN coating was found able to provide protection against mechanical damage, while the Ti interlayer improved the corrosion properties in an aggressive environment.

  11. Effect of Secondary Phase Precipitation on the Corrosion Behavior of Duplex Stainless Steels

    Directory of Open Access Journals (Sweden)

    Kai Wang Chan

    2014-07-01

    Full Text Available Duplex stainless steels (DSSs with austenitic and ferritic phases have been increasingly used for many industrial applications due to their good mechanical properties and corrosion resistance in acidic, caustic and marine environments. However, DSSs are susceptible to intergranular, pitting and stress corrosion in corrosive environments due to the formation of secondary phases. Such phases are induced in DSSs during the fabrication, improper heat treatment, welding process and prolonged exposure to high temperatures during their service lives. These include the precipitation of sigma and chi phases at 700–900 °C and spinodal decomposition of ferritic grains into Cr-rich and Cr-poor phases at 350–550 °C, respectively. This article gives the state-of the-art review on the microstructural evolution of secondary phase formation and their effects on the corrosion behavior of DSSs.

  12. A middle age addicted man with caustic stomach

    Directory of Open Access Journals (Sweden)

    Gholamreza Nouri Broujerdi

    2014-06-01

    Full Text Available Background: The term caustic generally refers to alkaline and the term corrosive generally refers to acidic agents' injury; however, in medical literature caustic is frequently a term applied to both substances. Ingested alkali typically damage the esophagus more than stomach or duodenum, whereas acids usually cause more severe gastric injury. Since esophagus has a slightly alkaline pH, its epithelium is more resistant to acids, so that only 6 to 20% of those who ingest these substances present lesions in this organ. Case : A middle-aged addicted man who drunk hydrochloric acid accidentally had extensive necrosis of the stomach with remarkable sparing of the esophagus on second look exploration. A total gastrectomy with a Roux-en-Y esophago-jejunostomy with feeding jejunostomy was performed. Conclusion : In caustic GI injury, patients who are operated on and found to have no evidence of extensive esophago-gastric necrosis, a biopsy of the posterior gastric wall should be performed to exclude occult injury. If histologically there is a question of viability, a second look operation should be performed within 36 hours.

  13. Irradiation-Assisted Stress Corrosion Cracking of Austenitic Stainless Steels in BWR Environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Chopra, O. K. [Argonne National Lab. (ANL), Argonne, IL (United States); Gruber, Eugene E. [Argonne National Lab. (ANL), Argonne, IL (United States); Shack, William J. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2010-06-01

    The internal components of light water reactors are exposed to high-energy neutron irradiation and high-temperature reactor coolant. The exposure to neutron irradiation increases the susceptibility of austenitic stainless steels (SSs) to stress corrosion cracking (SCC) because of the elevated corrosion potential of the reactor coolant and the introduction of new embrittlement mechanisms through radiation damage. Various nonsensitized SSs and nickel alloys have been found to be prone to intergranular cracking after extended neutron exposure. Such cracks have been seen in a number of internal components in boiling water reactors (BWRs). The elevated susceptibility to SCC in irradiated materials, commonly referred to as irradiation-assisted stress corrosion cracking (IASCC), is a complex phenomenon that involves simultaneous actions of irradiation, stress, and corrosion. In recent years, as nuclear power plants have aged and irradiation dose increased, IASCC has become an increasingly important issue. Post-irradiation crack growth rate and fracture toughness tests have been performed to provide data and technical support for the NRC to address various issues related to aging degradation of reactor-core internal structures and components. This report summarizes the results of the last group of tests on compact tension specimens from the Halden-II irradiation. The IASCC susceptibility of austenitic SSs and heat-affected-zone (HAZ) materials sectioned from submerged arc and shielded metal arc welds was evaluated by conducting crack growth rate and fracture toughness tests in a simulated BWR environment. The fracture and cracking behavior of HAZ materials, thermally sensitized SSs and grain-boundary engineered SSs was investigated at several doses (≤3 dpa). These latest results were combined with previous results from Halden-I and II irradiations to analyze the effects of neutron dose, water chemistry, alloy compositions, and welding and processing conditions on IASCC

  14. Effect of Stress Ratio and Loading Frequency on the Corrosion Fatigue Behavior of Smooth Steel Wire in Different Solutions

    Directory of Open Access Journals (Sweden)

    Songquan Wang

    2016-09-01

    Full Text Available In this work, the effects of loading condition and corrosion solution on the corrosion fatigue behavior of smooth steel wire were discussed. The results of polarization curves and weight loss curves showed that the corrosion of steel wire in acid solution was more severe than that in neutral and alkaline solutions. With the extension of immersion time in acid solution, the cathodic reaction of steel wire gradually changed from the reduction of hydrogen ion to the reduction of oxygen, but was always the reduction of hydrogen ion in neutral and alkaline solutions. The corrosion kinetic parameters and equivalent circuits of steel wires were also obtained by simulating the Nyquist diagrams. In corrosion fatigue test, the effect of stress ratio and loading frequency on the crack initiation mechanism was emphasized. The strong corrosivity of acid solution could accelerate the nucleation of crack tip. The initiation mechanism of crack under different conditions was summarized according to the side and fracture surface morphologies. For the crack initiation mechanism of anodic dissolution, the stronger the corrosivity of solution was, the more easily the fatigue crack source formed, while, for the crack initiation mechanism of deformation activation, the lower stress ratio and higher frequency would accelerate the generation of corrosion fatigue crack source.

  15. Assessment of Initial Test Conditions for Experiments to Assess Irradiation Assisted Stress Corrosion Cracking Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Busby, Jeremy T [ORNL; Gussev, Maxim N [ORNL

    2011-04-01

    Irradiation-assisted stress corrosion cracking is a key materials degradation issue in today s nuclear power reactor fleet and affects critical structural components within the reactor core. The effects of increased exposure to irradiation, stress, and/or coolant can substantially increase susceptibility to stress-corrosion cracking of austenitic steels in high-temperature water environments. . Despite 30 years of experience, the underlying mechanisms of IASCC are unknown. Extended service conditions will increase the exposure to irradiation, stress, and corrosive environment for all core internal components. The objective of this effort within the Light Water Reactor Sustainability program is to evaluate the response and mechanisms of IASCC in austenitic stainless steels with single variable experiments. A series of high-value irradiated specimens has been acquired from the past international research programs, providing a valuable opportunity to examine the mechanisms of IASCC. This batch of irradiated specimens has been received and inventoried. In addition, visual examination and sample cleaning has been completed. Microhardness testing has been performed on these specimens. All samples show evidence of hardening, as expected, although the degree of hardening has saturated and no trend with dose is observed. Further, the change in hardening can be converted to changes in mechanical properties. The calculated yield stress is consistent with previous data from light water reactor conditions. In addition, some evidence of changes in deformation mode was identified via examination of the microhardness indents. This analysis may provide further insights into the deformation mode under larger scale tests. Finally, swelling analysis was performed using immersion density methods. Most alloys showed some evidence of swelling, consistent with the expected trends for this class of alloy. The Hf-doped alloy showed densification rather than swelling. This observation may be

  16. Study on H2S stress corrosion test of welded joint for X65 pipeline steel and numerical analysis

    Institute of Scientific and Technical Information of China (English)

    金晓军; 霍立兴; 张玉凤; 白秉仁; 李晓巍; 曹军

    2004-01-01

    The susceptibility of welded joint for the X65 pipeline steel to H2S stress corrosion cracking (SCC) is investigated. SCC tests on the steel are carried out in the environment based on NACE TM-01-77 solution with saturated gaseous H2S. The threshold stress intensity factor and crack propagation velocity are calculated according to wedge-opening loading (WOL) specimens. The three-dimensional elastic-plastic finite element analysis of WOL specimens is performed by using the FEM programming package ANSYS. Stress field and concentration of hydrogen distribution property ahead of the crack tip are obtained. This paper surveyed the microstructure of welded joint and studied on the mechanical properties of X65 pipeline steel. It provides experimental basis for studying stress corrosion. The results of numerical analysis are consistent with conclusions of stress corrosion test.

  17. Simulation of Mechanical Stress on Stainless Steel for Pb-Bi Corrosion Test by Using ABAQUS

    Science.gov (United States)

    Irwanto, D.; Mustari, A. P. A.; Budiman, B. A.

    2017-03-01

    Pb-Bi eutectic with its advantageous is proposed to be utilized as a coolant in the GEN IV type of rSeactor. However, high temperature corrosion when contact with stainless steels is one of the issues of Pb-Bi eutectic utilization. It is known that in the environment of high temperature Pb-Bi, mechanical strength of stainless steel may decrease. Thus, simulation of mechanical stress working on stainless steel during in-situ bending test by using ABAQUS was conducted. Several bending degrees were simulated at high temperature to obtain the mechanical stress information. Temperature condition was strongly affect the stress vs. displacement profile. The reported mechanical strength reduction percentage was used to draw predicted mechanical stress under high temperature Pb-Bi environment.

  18. Stress corrosion crack initiation of alloy 182 weld metal in primary coolant - Influence of chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Calonne, O.; Foucault, M.; Steltzlen, F. [AREVA (France); Amzallag, C. [EDF SEPTEN (France)

    2011-07-01

    Nickel-base alloys 182 and 82 have been used extensively for dissimilar metal welds. Typical applications are the J-groove welds of alloy 600 vessel head penetrations, pressurizer penetrations, heater sleeves and bottom mounted instrumented nozzles as well as some safe end butt welds. While the overall performance of these weld metals has been good, during the last decade, an increasing number of cases of stress corrosion cracking of Alloy 182 weld metal have been reported in PWRs. In this context, the role of weld defects has to be examined. Their contribution in the crack initiation mechanism requires laboratory investigations with small scale characterizations. In this study, the influence of both alloy composition and weld defects on PWSCC (Stress Corrosion Cracking in Primary Water) initiation was investigated using U-bend specimens in simulated primary water at 320 C. The main results are the following: -) the chemical compositions of the weld deposits leading to a large propensity to hot cracking are not the most susceptible to PWSCC initiation, -) macroscopically, superficial defects did not evolve during successive exposures. They can be included in large corrosion cracks but their role as 'precursors' is not yet established. (authors)

  19. Literature Survey on the Stress Corrosion Cracking of Low-Alloy Steels in High Temperature Water

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.P

    2002-02-01

    The present report is a summary of a literature survey on the stress corrosion cracking (SCC) behaviour/ mechanisms in low-alloy steels (LAS) in high-temperature water with special emphasis to primary-pressure-boundary components of boiling water reactors (BWR). A brief overview on the current state of knowledge concerning SCC of low-alloy reactor pressure vessel and piping steels under BWR conditions is given. After a short introduction on general aspects of SCC, the main influence parameter and available quantitative literature data concerning SCC of LAS in high-temperature water are discussed on a phenomenological basis followed by a summary of the most popular SCC models for this corrosion system. The BWR operating experience and service cracking incidents are discussed with respect to the existing laboratory data and background knowledge. Finally, the most important open questions and topics for further experimental investigations are outlined. (author)

  20. Stress corrosion cracking in low-pressure turbine discs in an NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Hitomi, Itoh [Mitsubishi Heavy Industries, Ltd., Takasago Research and Development Center (Japan); Takashi, Momoo [Mitsubishi Heavy Industries, Ltd., Takasago Machinery Works (Japan)

    2001-07-01

    From past research, it is known that stress corrosion cracking in low-pressure turbine discs occurs in an environment near that of deaerated pure water. Nevertheless, in units with molar ratio control, there is a possibility of NaCl concentrating as an impurity in the dry/wet boundary region. Long-term immersion tests were conducted at 373 K to 473 K with the NaCl concentration predicted to become 5%. It was found that, when FeCl{sub 3} or other oxidizer was added, corrosion increased remarkably and SCC was initiated. When cracks were initiated, they were primarily transgranular; as the test temperature was decreased, initiation was accelerated but conversely crack propagation was reduced. (author)

  1. Stress Corrosion Cracking Behavior of Alloy 22 in Multi-Ionic Aqueous Environments

    Energy Technology Data Exchange (ETDEWEB)

    K.J. King; J.C. Estill; R.B. Rebak

    2002-07-15

    The US Department of Energy is characterizing a potential repository site for nuclear waste in Yucca Mountain (NV). In its current design, the nuclear waste containers consist of a double metallic layer. The external layer would be made of NO6022 or Alloy 22 (Ni-22Cr-13Mo-3W-3Fe). Since over their lifetime, the containers may be exposed to multi-ionic aqueous environments, a potential degradation mode of the outer layer could be environmentally assisted cracking (EAC) or stress corrosion cracking (SCC). In general, Alloy 22 is extremely resistant to SCC, especially in concentrated chloride solutions. Current results obtained through slow strain rate testing (SSRT) shows that Alloy 22 may suffer SCC in simulated concentrated water (SCW) at applied potentials approximately 400 mV more anodic than the corrosion potential (E{sub rr}).

  2. Corrosion Fatigue of High-Strength Titanium Alloys Under Different Stress Gradients

    Science.gov (United States)

    Baragetti, Sergio; Villa, Francesco

    2015-05-01

    Ti-6Al-4V is the most widely used high strength-to-mass ratio titanium alloy for advanced engineering components. Its adoption in the aerospace, maritime, automotive, and biomedical sectors is encouraged when highly stressed components with severe fatigue loading are designed. The extents of its applications expose the alloy to several aggressive environments, which can compromise its brilliant mechanical characteristics, leading to potentially catastrophic failures. Ti-6Al-4V stress-corrosion cracking and corrosion-fatigue sensitivity has been known since the material testing for pressurized tanks for Apollo missions, although detailed investigations on the effects of harsh environment in terms of maximum stress reduction have been not carried out until recent times. In the current work, recent experimental results from the authors' research group are presented, quantifying the effects of aggressive environments on Ti-6Al-4V under fatigue loading in terms of maximum stress reduction. R = 0.1 axial fatigue results in laboratory air, 3.5 wt.% NaCl solution, and CH3OH methanol solution at different concentrations are obtained for mild notched specimens ( K t = 1.18) at 2e5 cycles. R = 0.1 tests are also conducted in laboratory air, inert environment, 3.5 wt.% NaCl solution for smooth, mild and sharp notched specimens, with K t ranging from 1 to 18.65, highlighting the environmental effects for the different load conditions induced by the specimen geometry.

  3. Hierarchical Petascale Simulation Framework For Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Grama, Ananth

    2013-12-18

    A number of major accomplishments resulted from the project. These include: • Data Structures, Algorithms, and Numerical Methods for Reactive Molecular Dynamics. We have developed a range of novel data structures, algorithms, and solvers (amortized ILU, Spike) for use with ReaxFF and charge equilibration. • Parallel Formulations of ReactiveMD (Purdue ReactiveMolecular Dynamics Package, PuReMD, PuReMD-GPU, and PG-PuReMD) for Messaging, GPU, and GPU Cluster Platforms. We have developed efficient serial, parallel (MPI), GPU (Cuda), and GPU Cluster (MPI/Cuda) implementations. Our implementations have been demonstrated to be significantly better than the state of the art, both in terms of performance and scalability. • Comprehensive Validation in the Context of Diverse Applications. We have demonstrated the use of our software in diverse systems, including silica-water, silicon-germanium nanorods, and as part of other projects, extended it to applications ranging from explosives (RDX) to lipid bilayers (biomembranes under oxidative stress). • Open Source Software Packages for Reactive Molecular Dynamics. All versions of our soft- ware have been released over the public domain. There are over 100 major research groups worldwide using our software. • Implementation into the Department of Energy LAMMPS Software Package. We have also integrated our software into the Department of Energy LAMMPS software package.

  4. Microstructural investigation of vintage pipeline steels highly susceptible to stress corrosion cracking

    Science.gov (United States)

    Torres, Monica

    The use of pipelines for the transmission of gas offers not only efficiency, but a number of economic advantages. Nevertheless, pipelines are subject to aggressive operating conditions and environments which can lead to in-service degradation [1] and thus to failures. These failures can have catastrophic consequences, such as environmental damage and loss of life [2]. One of the most dangerous threats to pipeline integrity is stress corrosion cracking (SCC). Despite the substantial progress that has been achieved in the field, due to the complex nature of this phenomenon there is still not a complete understanding of this form of external corrosion. This makes its detection and prevention a challenge and therefore a risk to pipeline integrity, and most importantly, to the safety of the population. SCC cracks are the result of the interaction between a corrosive environment, applied stresses, and a susceptible microstructure. To date, what defines a susceptible microstructure remains ambiguous, as SCC has been observed in a range of steel grades, microstructures, chemical composition, and grain sizes. Therefore, in order to be able to accurately predict and prevent this hazardous form of corrosion, it is imperative to advance our knowledge on the subject and gain a better understanding on the microstructural features of highly susceptible pipeline materials, especially in the subsurface zone where crack nucleation must take place. Therefore, a microstructural characterization of the region near the surface layer was carried-out utilizing TEM. TEM analysis revealed the dislocation character, ferrite morphology, and apparent carbide precipitation in some grain boundaries. Furthermore, light microscopy, SEM, and hardness testing were performed to expand our knowledge on the microscopical features of highly SCC susceptible service components. This investigation presents a new approach to SCC characterization, which exposed the sub-surface region microscopical

  5. Applied methods for mitigation of damage by stress corrosion in BWR type reactors; Metodos aplicados para la mitigacion del dano por corrosion bajo esfuerzo en reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez C, R.; Diaz S, A.; Gachuz M, M.; Arganis J, C. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Ciencia de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    The Boiling Water nuclear Reactors (BWR) have presented stress corrosion problems, mainly in components and pipes of the primary system, provoking negative impacts in the performance of energy generator plants, as well as the increasing in the radiation exposure to personnel involucred. This problem has caused development of research programs, which are guided to find solution alternatives for the phenomena control. Among results of greater relevance the control for the reactor water chemistry stands out particularly in the impurities concentration and oxidation of radiolysis products; as well as the supervision in the materials selection and the stresses levels reduction. The present work presents the methods which can be applied to diminish the problems of stress corrosion in BWR reactors. (Author)

  6. Causticity and Anti-corrosion Measures for Soil in Northwest Gobi Region%西北戈壁地区岩土腐蚀性与防腐措施分析

    Institute of Scientific and Technical Information of China (English)

    任治军; 任亚群; 宋志远

    2013-01-01

      本文针对±800kV哈密南-郑州特高压直流输电线路工程的岩土工程勘测实践,对西北戈壁地区特高压送电线路工程的场地土腐蚀性评价工作方法进行了论述,主要包括样本采取原则、取样点布置、试验结果分析等。在分析试验成果的基础上,根据规范对线路地基土的腐蚀性进行了综合评价,并提出了相应的防腐处理建议。%This thesis focuses on the geotechnical engineering practice of the 800kV direct-current (DC) transmission line project from south of Hami to Zhengzhou. Corrosive evaluation methods for site soil of the ultra-high voltage transmission line engineering in Northwest Gobi region are discussed, mainly including sampling principle, sampling point layout and test result analysis, etc. Based on the analysis of test results, comprehensive foundation soil corrosive evaluation is conducted and corresponding suggestions on anti-corrosive treatment are put forward according to relevant codes.

  7. The effect of heat treatment and test parameters on the aqueous stress corrosion cracking of D6AC steel

    Science.gov (United States)

    Gilbreath, W. P.; Adamson, M. J.

    1974-01-01

    The crack growth behavior of D6AC steel as a function of stress intensity, stress and corrosion history and test technique, under sustained load in natural seawater, 3.3 percent NaCl solution, distilled water, and high humidity air was investigated. Reported investigations of D6AC were considered with emphasis on thermal treatment, specimen configuration, fracture toughness, crack-growth rates, initiation period, threshold, and the extension of corrosion fatigue data to sustained load conditions. Stress history effects were found to be most important in that they controlled incubation period, initial crack growth rates, and apparent threshold.

  8. Stress corrosion cracking and its anisotropy of a PZT ferroelectric ceramics

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist atmosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, KISCC, revealed anisotropy. The KISCC for poling direction parallel to the crack plane, was greater than that perpendicular to the crack plane, similar to the anisotropy of fracture toughness KIC; however, the anisotropy factor of KISCC, which was =1.8 (in formamide) and 2.1 (in water), was larger than that of KIC, which is =1.4. The stress-induced 90° domain switching causes the anisotropy of KIC and KISCC, besides, the resistance of SCC also has anisotropy.

  9. Mechanical factors in primary water stress corrosion cracking of cold-worked stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Hammadi, Rashid Al, E-mail: rashid.alhammadi@fanr.gov.ae [Nuclear Security Division, Federal Authority for Nuclear Regulation, Abu Dhabi (United Arab Emirates); Yi, Yongsun, E-mail: yongsun.yi@kustar.ac.ae [Department of Nuclear Engineering, Khalifa University, Abu Dhabi (United Arab Emirates); Zaki, Wael, E-mail: wael.zaki@kustar.ac.ae [Department of Mechanical Engineering, Khalifa University, Abu Dhabi (United Arab Emirates); Cho, Pyungyeon, E-mail: pyungyeon.cho@kustar.ac.ae [Department of Nuclear Engineering, Khalifa University, Abu Dhabi (United Arab Emirates); Jang, Changheui, E-mail: chjang@kaist.ac.kr [Nuclear and Quantum Engineering Department, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-05-15

    Highlights: • PWSCC of cold-worked austenitic stainless steel was studied. • Finite element analysis was performed on a compact tension specimen. • Mechanical fields near a crack tip were evaluated using FEA. • The dependence of mechanical factors on K{sub I} and yield stress was investigated. • The crack tip normal stress was identified as a main factor controlling PWSCC. - Abstract: Finite element analysis was performed on a compact tension specimen to determine the stress and strain distributions near a crack tip. Based on the results, the crack tip stain rates by crack advance and creep rates near crack tip were estimated. By comparing the dependence of the mechanical factors on the stress intensity factor and yield stress with that of the SCC crack growth rates, it was tried to identify the main mechanical factor for the primary water stress corrosion cracking (PWSCC) of cold-worked austenitic stainless steels. The analysis results showed that the crack tip normal stress could be the main mechanical factor controlling the PWSCC, suggesting that the internal oxidation mechanism might be the most probable PWSCC mechanism of cold-worked austenitic stainless steels.

  10. Effect of layerwise structural inhomogeneity on stress- corrosion cracking of steel tubes

    Science.gov (United States)

    Perlovich, Yu A.; Krymskaya, O. A.; Isaenkova, M. G.; Morozov, N. S.; Fesenko, V. A.; Ryakhovskikh, I. V.; Esiev, T. S.

    2016-04-01

    Based on X-ray texture and structure analysis data of the material of main gas pipelines it was shown that the layerwise inhomogeneity of tubes is formed during their manufacturing. The degree of this inhomogeneity affects on the tendency of tubes to stress- corrosion cracking under exploitation. Samples of tubes were cut out from gas pipelines located under various operating conditions. Herewith the study was conducted both for sections with detected stress-corrosion defects and without them. Distributions along tube wall thickness for lattice parameters and half-width of X-ray lines were constructed. Crystallographic texture analysis of external and internal tube layers was also carried out. Obtained data testifies about considerable layerwise inhomogeneity of all samples. Despite the different nature of the texture inhomogeneity of gas pipeline tubes, the more inhomogeneous distribution of texture or structure features causes the increasing of resistance to stress- corrosion. The observed effect can be explained by saturation with interstitial impurities of the surface layer of the hot-rolled sheet and obtained therefrom tube. This results in rising of lattice parameters in the external layer of tube as compared to those in underlying metal. Thus, internal layers have a compressive effect on external layers in the rolling plane that prevents cracks opening at the tube surface. Moreover, the high mutual misorientation of grains within external and internal layers of tube results in the necessity to change the moving crack plane, so that the crack growth can be inhibited when reaching the layer with a modified texture.

  11. Laboratory evaluation of soil stress corrosion cracking and hydrogen embrittlement of API grade steels

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, A.H.S.; Castro, B.B.; Ponciano, J.A.C. [Federal Univ. of Rio de Janeiro (Brazil). COPPE

    2004-07-01

    Stress corrosion cracking (SCC) in carbon steels is a form of deterioration that can occur during the service life of a pipeline that is exposed to mechanical stress and strains. A study was conducted to investigate SCC and hydrogen embrittlement (HE) of API grade steels in contact with soil. The physical, chemical and bacteriological characteristics of different soil samples were determined. Slow strain rate tests were performed using electrolytes obtained in the soil samples taken from different points near buried pipelines. Stress versus strain curves were obtained at different electrode potentials for API X46, X60 and X80 steels. The results showed the conjoint incidence of SCC and HE, depending on the potential imposed. It was revealed that HE contributes to the initiation of cracking and crack propagation. Cracking morphology was similar to the SCC found in field situations where transgranular cracking was detected in a pipeline that had collapsed as a result of land creeping. The material exhibited signs of secondary cracking and lower ductility, even under cathodic potentials. It was noted that the methodology used in this study was not able to reproduce the possible effect of microbial induced corrosion. 10 refs., 3 tabs., 3 figs.

  12. Relationship between localized strain and irradiation assisted stress corrosion cracking in an austenitic alloy

    Energy Technology Data Exchange (ETDEWEB)

    McMurtrey, M.D., E-mail: mdmcm@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Was, G.S. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Patrick, L.; Farkas, D. [Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24061 (United States)

    2011-04-25

    Research highlights: {yields} Austenitic steel is more susceptible to intergranular corrosion after irradiation. {yields} Simulation and experiment used to study cracking in irradiated austentic steel. {yields} Cracking occurs at random high angle boundaries normal to the tensile stress. {yields} Cracking at boundaries with high normal stress and inability to accommodate strain. {yields} Boundary type, angle, and Taylor and Schmid factors affect strain accommodation. - Abstract: Irradiation assisted stress corrosion cracking may be linked to the local slip behavior near grain boundaries that exhibit high susceptibility to cracking. Fe-13Cr-15Ni austenitic steel was irradiated with 2 MeV protons at 360 deg. C to 5 dpa and strained in 288 deg. C simulated BWR conditions. Clusters of grains from the experiment were created in an atomistic simulation and then virtually strained using molecular dynamic simulation techniques. Cracking and grain orientation data were characterized in both the experiment and the simulation. Random high angle boundaries with high surface trace angles with respect to the tensile direction were found to be the most susceptible to cracking. Grain boundary cracking susceptibility was also found to correlate strongly with slip continuity, indicating that the strain accommodation at the boundary is related to cracking resistance. Higher cracking susceptibility was also found at grain boundaries adjacent to grains with low Schmid factor or high Taylor factor. The basic trends reported here are supported by both the experiments and the simulations.

  13. Statistical model of stress corrosion cracking based on extended form of Dirichlet energy: Part 2

    Indian Academy of Sciences (India)

    HARRY YOSH

    2016-10-01

    In the previous paper ({\\it Pramana – J. Phys.} 81(6), 1009 (2013)), the mechanism of stress corrosion cracking (SCC) based on non-quadratic form of Dirichlet energy was proposed and its statistical features were discussed. Following those results, we discuss here how SCC propagates on pipe wall statistically. It reveals that SCC growth distribution is described with Cauchy problem of time-dependent first-order partial differential equation characterized by the convolution of the initial distribution of SCC over time. We also discuss the extension of the above results to the SCC in two-dimensional space and its statistical features with a simple example.

  14. Statistical model of stress corrosion cracking based on extended form of Dirichlet energy

    Indian Academy of Sciences (India)

    Harry Yosh

    2013-12-01

    The mechanism of stress corrosion cracking (SCC) has been discussed for decades. Here I propose a model of SCC reflecting the feature of fracture in brittle manner based on the variational principle under approximately supposed thermal equilibrium. In that model the functionals are expressed with extended forms of Dirichlet energy, and Dirichlet principle is applied to them to solve the variational problem that represents SCC and normal extension on pipe surface. Based on the model and the maximum entropy principle, the statistical nature of SCC colony is discussed and it is indicated that the crack has discrete energy and length under ideal isotropy of materials and thermal equilibrium.

  15. INHIBITION OF STRESS CORROSION CRACKING OF CARBON STEEL STORAGE TANKS AT HANFORD

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-01-31

    The stress corrosion cracking (SCC) behavior of A537 tank steel was investigated in a series of environments designed to simulate the chemistry of legacy nuclear weapons production waste. Tests consisted of both slow strain rate tests using tensile specimens and constant load tests using compact tension specimens. Based on the tests conducted, nitrite was found to be a strong SCC inhibitor. Based on the test performed and the tank waste chemistry changes that are predicted to occur over time, the risk for SCC appears to be decreasing since the concentration of nitrate will decrease and nitrite will increase.

  16. Intergranular stress corrosion cracking of welded ferritic stainless steels in high temperature aqueous environments

    Energy Technology Data Exchange (ETDEWEB)

    Fukuzuka, Toshio; Shimogori, Kazutoshi; Fujiwara, Kazuo; Tomari, Haruo (Kobe Steel Ltd. (Japan). Central Research and Development Lab.); Kanda, Masao

    1982-07-01

    In considering the application of ferritic stainless steels to heat exchanger tubing materials for moisture separator-reheaters in LWRs, the effects of environmental conditions (temperature, chloride, dissolved oxygen, pH), thermal history, and steel composition (content of C, N, Cr and Ti) on the Inter-Granular Stress Corrosion Cracking (IGSCC) in high temperature aqueous environments, were studied. The IGSCC was proved to depend on steel composition and thermal history rather than environment. From these results, a steel was designed to prevent IGSCC of the welding HAZ for 18Cr and 13Cr steels.

  17. Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material

    Energy Technology Data Exchange (ETDEWEB)

    G. Gordon

    2004-10-13

    Stress corrosion cracking is one of the most common corrosion-related causes for premature breach of metal structural components. Stress corrosion cracking is the initiation and propagation of cracks in structural components due to three factors that must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. This report was prepared according to ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of this report is to provide an evaluation of the potential for stress corrosion cracking of the engineered barrier system components (i.e., the drip shield, waste package outer barrier, and waste package stainless steel inner structural cylinder) under exposure conditions consistent with the repository during the regulatory period of 10,000 years after permanent closure. For the drip shield and waste package outer barrier, the critical environment is conservatively taken as any aqueous environment contacting the metal surfaces. Appendix B of this report describes the development of the SCC-relevant seismic crack density model (SCDM). The consequence of a stress corrosion cracking breach of the drip shield, the waste package outer barrier, or the stainless steel inner structural cylinder material is the initiation and propagation of tight, sometimes branching, cracks that might be induced by the combination of an aggressive environment and various tensile stresses that can develop in the drip shields or the waste packages. The Stainless Steel Type 316 inner structural cylinder of the waste package is excluded from the stress corrosion cracking evaluation because the Total System Performance Assessment for License Application (TSPA-LA) does not take credit for the inner cylinder. This document provides a detailed description of the process-level models that can be applied to assess the

  18. A Study on the Residual Stress Improvement of PWSCC(Primary Water Stress Corrosion Cracking) in DMW(Dissimilar Metal Weld)

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Sik; Kim, Seok Hun; Lee, Seung Gun [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Park, Heung Bae [KEPCO Engineering and Construction Company, Daejeon (Korea, Republic of)

    2010-10-15

    Since 2000s, most of the cracks are found in welds, especially in (DMW) dissimilar metal welds such as pressurizer safety relief nozzle, reactor head penetration, reactor bottom mounted instrumentation (BMI), and reactor nozzles. Even the cracks are revealed as a primary water stress corrosion cracking (PWSCC), it is difficult to find the cracks by current non destructive examination. The PWSCC is occurred by three incident factors, such as susceptible material, environmental corrosive condition, and welding residual stress. If one of the three factors can be erased or decreased, the PWSCC could be prevented. In this study, we performed residual stress analysis for DMW and several residual stress improvement methods. As the preventive methods of PWSCC, we used laser peening(IP) method, inlay weld(IW) method, and induction heating stress improvement(IHSI) method. The effect of residual stress improvement for preventive methods was compared and discussed by finite element modeling and residual stress of repaired DMW

  19. Caustic Ingestion in Children: a Systematic Review and Meta-Analysis

    Science.gov (United States)

    Rafeey, Mandana; Ghojazadeh, Morteza; Sheikhi, Saeede; Vahedi, Leila

    2016-01-01

    Introduction:Caustic ingestion that occurs accidently is one of the most common problems in children. Methods: This systematic review has been performed by searching the databases including Science Direct, ProQuest, Google Scholar, and PubMed. A strategic search was performed with keywords including caustic, corrosive, ingestion, and children, and was limited to articles in English and Persian. Data were analyzed using Comprehensive Meta-Analysis2 and PASW Statistics 18. Results: We selected 64 articles regarding caustic ingestion with a total sample of 11,345 cases. The data analysis indicated a higher consumption in young boys (age range 2.78 (2.02) years (OR=0.53 with a 95% confidence interval of 0.49-0.57 (P=0.08)). The most common caustic substances were household cleaning agents, particularly bleaches and cleaners. Esophageal cancer and death were reported as well as digestive and respiratory complications. Invasive and expensive techniques are frequently used for diagnosis, treatment and follow up. Conclusion: The results demonstrated that although caustic ingestion is a serious problem among children, it is a preventable and manageable issue. Therefore, appropriate efforts by families, government, factories, health team and media should be made to handle adequately this matter.

  20. Corrosion behavior of 2195 and 1420 Al-Li alloys in neutral 3.5% NaCl solution under tensile stress

    Institute of Scientific and Technical Information of China (English)

    LI Jin-feng; CHEN Wen-jing; ZHAO Xu-shan; REN Wen-da; ZHENG Zi-qiao

    2006-01-01

    The corrosion behaviors of 1420 and 2195 Al-Li alloys under 308 and 490 MPa tensile stress respectively in neutral 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy(EIS) and scanning electron microscope(SEM). It is found that the unstressed 1420 alloy is featured with large and discrete pits, while general corrosion and localized corrosion including intergranular corrosion and pitting corrosion occur on the unstressed 2195 alloy. As stress is applied to 1420 alloy, the pit becomes denser and its size is decreased. While, for the stressed 2195 alloy, intergranular corrosion is greatly aggravated and severe general corrosion is developed from connected pits. The EIS analysis shows that more severe general corrosion and localized corrosion occur on the stressed 2195 Al-Li alloy than on 1420 Al-Li alloy. It is suggested that tensile stress has greater effect on the corrosion of 2195 Al-Li alloy than on 1420 Al-Li alloy.

  1. Modeling of Stress Corrosion Cracking for High Level Radioactive-Waste Packages

    Energy Technology Data Exchange (ETDEWEB)

    Lu, S C; Gordon, G M; Andresen, P L; Herrera, M L

    2003-06-20

    A stress corrosion cracking (SCC) model has been adapted for performance prediction of high level radioactive-waste packages to be emplaced in the proposed Yucca Mountain radioactive-waste repository. SCC is one form of environmentally assisted cracking due to three factors, which must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. For waste packages of the proposed Yucca Mountain repository, the outer barrier material is Alloy 22, a highly corrosion resistant alloy, the environment is represented by the water film present on the surface of the waste package from dripping or deliquescence of soluble salts present in any surface deposits, and the stress is principally the weld induced residual stress. SCC has historically been separated into ''initiation'' and ''propagation'' phases. Initiation of SCC will not occur on a smooth surface if the surface stress is below a threshold value defined as the threshold stress. Cracks can also initiate at and propagate from flaws (or defects) resulting from manufacturing processes (such as welding). To account for crack propagation, the slip dissolution/film rupture (SDFR) model is adopted to provide mathematical formulas for prediction of the crack growth rate. Once the crack growth rate at an initiated SCC is determined, the time to through-wall penetration for the waste package can be calculated. The SDFR model relates the advance (or propagation) of cracks, subsequent to the crack initiation from bare metal surface, to the metal oxidation transients that occur when the protective film at the crack tip is continually ruptured and repassivated. A crack, however, may reach the ''arrest'' state before it enters the ''propagation'' phase. There exists a threshold stress intensity factor, which provides a criterion for determining if an initiated crack or pre

  2. Uncertainty quantification methodologies development for stress corrosion cracking of canister welds

    Energy Technology Data Exchange (ETDEWEB)

    Dingreville, Remi Philippe Michel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bryan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-09-30

    This letter report presents a probabilistic performance assessment model to evaluate the probability of canister failure (through-wall penetration) by SCC. The model first assesses whether environmental conditions for SCC – the presence of an aqueous film – are present at canister weld locations (where tensile stresses are likely to occur) on the canister surface. Geometry-specific storage system thermal models and weather data sets representative of U.S. spent nuclear fuel (SNF) storage sites are implemented to evaluate location-specific canister surface temperature and relative humidity (RH). As the canister cools and aqueous conditions become possible, the occurrence of corrosion is evaluated. Corrosion is modeled as a two-step process: first, pitting is initiated, and the extent and depth of pitting is a function of the chloride surface load and the environmental conditions (temperature and RH). Second, as corrosion penetration increases, the pit eventually transitions to a SCC crack, with crack initiation becoming more likely with increasing pit depth. Once pits convert to cracks, a crack growth model is implemented. The SCC growth model includes rate dependencies on both temperature and crack tip stress intensity factor, and crack growth only occurs in time steps when aqueous conditions are predicted. The model suggests that SCC is likely to occur over potential SNF interim storage intervals; however, this result is based on many modeling assumptions. Sensitivity analyses provide information on the model assumptions and parameter values that have the greatest impact on predicted storage canister performance, and provide guidance for further research to reduce uncertainties.

  3. Flaw growth of 7075, 7475, 7050 and 7049 aluminum alloy plate in stress corrosion environments

    Science.gov (United States)

    Dorward, R. C.; Hasse, K. R.

    1976-01-01

    Marine atmosphere and laboratory stress corrosion test results on smooth and precracked specimens from 7075, 7475, 7050, and 7049 alloy plates (1.25 and 3.0-in. thick) are presented. It is shown that for a given strength level, alloys 7050-T7X and 7049-T7X have superior short-transverse stress corrosion resistance (SCR) to 7X75-T7X. At typical strength levels above the minimum, for example, SCR of these alloys is considerably better than that of 7075-T76, and approaches that of 7075-T73. Alloy 7475 maintains an advantage in the area of fracture toughness, however, because it can be thermally processed to give particularly clean microstructures. Results from precracked specimens are in good qualitative agreement with those obtained from smooth specimens. Although both specimen types are capable of distinguishing between -T6, -T76 and -T73 tempers in relatively short time periods the precracked specimen provides more information about crack growth rates.

  4. Evaluation of irradiation assisted stress corrosion cracking (IASCC) of type 316 stainless steel irradiated in FBR

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, T. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)); Jitsukawa, S. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)); Shiba, K. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)); Sato, Y. (Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan)); Shibahara, I. (Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan)); Nakajima, H. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan))

    1993-12-01

    Type 316 stainless steel from the core of the experimental fast breeder reactor (FBR) JOYO was examined by the slow strain rate tensile (SSRT) test in pure, oxygenated-water and air and by the electrochemical potentiokinetic reactivation (EPR) test to evaluate a susceptibility to the irradiation assisted stress corrosion cracking (IASCC) and the radiation-induced segregation (RIS). The solution annealed and 20% cold-worked materials had been irradiated at 425 C to a neutron fluence of 8.3x10[sup 26] n/m[sup 2] (> 0.1 MeV) which is equivalent to 40 displacement per atom (dpa). Intergranular cracking was induced by the SSRT in water at 200 and 300 C, but was not observed on specimen tested in water at 60 C and in air at 300 C. This indicates that irradiation increased a susceptibility to stress corrosion cracking (SCC) in water. After the EPR test, grain boundary etching was observed in addition to grain face etching. This suggests Cr depletion may have occurred both at grain boundary and at defect clusters during the irradiation. The results are compared with the behavior of similar materials irradiated with different neutron spectrum. (orig.)

  5. In-situ caustic generation from sewage: the impact of caustic strength and sewage composition.

    Science.gov (United States)

    Pikaar, Ilje; Rozendal, René A; Rabaey, Korneel; Yuan, Zhiguo

    2013-10-01

    Periodic caustic dosage is a commonly used method by the water industry to elevate pH levels and deactivate sewer biofilms responsible for hydrogen sulfide generation. Caustic (NaOH) can be generated in-situ from sewage using a divided electrochemical cell, which avoids the need for transport, handling and storage of concentrated caustic solutions. In this study, we investigated the impact of caustic strength in the cathode compartment and the impact of sodium concentration in sewage on the Coulombic efficiency (CE) for caustic generation. The CE was found to be independent of the caustic strength produced in the range of up to ~3 wt%. Results showed that a caustic solution of ~3 wt% could be produced directly from sewage at a CE of up to 75 ± 0.5%. The sodium concentration in sewage had a significant impact on the CE for caustic generation as well as on the energy requirements of the system, with a higher sodium concentration leading to a higher CE and lower energy consumption. The proton, calcium, magnesium and ammonium concentrations in sewage affected the CE for caustic generation, especially at low sodium concentrations. Economical assessment based on the experimental results indicated that sulfide control in sewers using electrochemically-generated caustic from sewage is an economically attractive strategy.

  6. Flat growth of 7075, 7475, 7050 and 7049 aluminum alloy plate in stress corrosion environments: 2-year marine atmosphere results

    Science.gov (United States)

    Dorward, R. C.; Hasse, K. R.

    1978-01-01

    Marine atmospheric exposure of smooth and precracked specimens from 7075, 7475, 7050 and 7049 plates support the conclusion that for a given strength level, the short transverse stress corrosion resistance of 7050-T7X and 7049-T7X is superior to that of 7075-T7X. The threshold stress intensity (K sub Iscc) for these alloys is about 25 MPa square root m at a yield strength of about 460 MPa; the corresponding yield strength level for 7075-T7X at this SCR level is about 425 MPa. Additional tests on two lots of high-toughness 7475 plate indicate that this alloy is capable of achieving K sub Iscc values of about 35 MPa square root m at yield strengths of 400-450 MPa. Precracked specimens from all these 7XXX-series alloys are subject to self loading from corrosion product wedging. This effect causes stress corrosion cracks to continue growing at very low apparent stress intensities, and should therefore be considered a potential driving force for stress corrosion in design and materials selection.

  7. Improved stress corrosion cracking resistance of a novel biodegradable EW62 magnesium alloy by rapid solidification, in simulated electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Hakimi, O.; Aghion, E. [Department of Materials Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Goldman, J., E-mail: jgoldman@mtu.edu [Biomedical Engineering Department, Michigan Technological University, Houghton, MI, 49931 (United States)

    2015-06-01

    The high corrosion rate of magnesium (Mg) and Mg-alloys precludes their widespread acceptance as implantable biomaterials. Here, we investigated the potential for rapid solidification (RS) to increase the stress corrosion cracking (SCC) resistance of a novel Mg alloy, Mg–6%Nd–2%Y–0.5%Zr (EW62), in comparison to its conventionally cast (CC) counterpart. RS ribbons were extrusion consolidated in order to generate bioimplant-relevant geometries for testing and practical use. Microstructural characteristics were examined by SEM. Corrosion rates were calculated based upon hydrogen evolution during immersion testing. The surface layer of the tested alloys was analyzed by X-ray photoelectron spectroscopy (XPS). Stress corrosion resistance was assessed by slow strain rate testing and fractography. The results indicate that the corrosion resistance of the RS alloy is significantly improved relative to the CC alloy due to a supersaturated Nd enrichment that increases the Nd{sub 2}O{sub 3} content in the external oxide layer, as well as a more homogeneous structure and reduced grain size. These improvements contributed to the reduced formation of hydrogen gas and hydrogen embrittlement, which reduced the SCC sensitivity relative to the CC alloy. Therefore, EW62 in the form of a rapidly solidified extruded structure may serve as a biodegradable implant for biomedical applications. - Highlights: • Here we have evaluated the corrosion resistance of a novel Mg alloy (EW62). • Rapid solidification reduces the hydrogen gas evolution and hydrogen embrittlement. • Rapid solidification increases the stress corrosion cracking resistance of EW62. • Improvement is due to enrichment with supersaturated Nd in the external oxide film. • Rapidly solidified and extruded EW62 may serve as a biodegradable medical implant.

  8. 27 CFR 21.102 - Caustic soda, liquid.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Caustic soda, liquid. 21....102 Caustic soda, liquid. (a) The liquid caustic soda may consist of either 50 percent or 73 percent by weight sodium hydroxide in aqueous solution. The amount of caustic soda used shall be such...

  9. Investigation into the stress corrosion cracking properties of AA2099, an aluminum-lithium-copper alloy

    Science.gov (United States)

    Padgett, Barbara Nicole

    Recently developed Al-Li-Cu alloys show great potential for implementation in the aerospace industry because of the attractive mix of good mechanical properties and low density. AA2099 is an Al-Li-Cu alloy with the following composition Al-2.69wt%Cu-1.8wt%Li-0.6wt%Zn-0.3wt%Mg-0.3wt%Mn-0.08wt%Zr. The environmental assisted cracking and localized corrosion behavior of the AA2099 was investigated in this thesis. The consequences of uncontrolled grain boundary precipitation via friction stir welding on the stress corrosion cracking (SCC) behavior of AA2099 was investigated first. Using constant extension rate testing, intergranular corrosion immersion experiments, and potentiodynamic scans, the heat-affected zone on the trailing edge of the weld (HTS) was determined to be most susceptible of the weld zones. The observed SCC behavior for the HTS was linked to the dissolution of an active phase (Al2CuLi, T1) populating the grain boundary. It should be stated that the SCC properties of AA2099 in the as-received condition were determined to be good. Focus was then given to the electrochemical behavior of precipitate phases that may occupy grain and sub-grain boundaries in AA2099. The grain boundary micro-chemistry and micro-electrochemistry have been alluded to within the literature as having significant influence on the SCC behavior of Al-Li-Cu alloys. Major precipitates found in this alloy system are T1 (Al 2CuLi), T2 (Al7.5Cu4Li), T B (Al6CuLi3), and theta (Al2 Cu). These phases were produced in bulk form so that the electrochemical nature of each phase could be characterized. It was determined T1 was most active electrochemically and theta was least. When present on grain boundaries in the alloy, electrochemical behavior of the individual precipitates aligned with the observed corrosion behavior of the alloy (e.g. TB was accompanied by general pitting corrosion and T 1 was accompanied by intergranular corrosion attack). In addition to the electrochemical behavior of

  10. Caustic Injury In Adults – A Study For 3 Year Period

    OpenAIRE

    2016-01-01

    The aim of the study is to present the results of a 3-year clinico-epidemiological investigation of caustic injury in adults. The study includes 43 patients with acute corrosive ingestion, hospitalized in the Toxicology Clinic, University Hospital “N. I. Pirogov”, Sofia, Bulgaria, for the period 01.01. 2010-31.12.2012. The methods used include: clinical observation and examination, clinical laboratory, imaging, and psychiatric methods and tests. 43 patients between the ages of 22 and 82 with ...

  11. Tensile stress corrosion cracking of type 304 stainless steel irradiated to very high dose

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Ruther, W. E.; Strain, R. V.; Shack, W. J.

    2001-09-01

    Certain safety-related core internal structural components of light water reactors, usually fabricated from Type 304 or 316 austenitic stainless steels (SSs), accumulate very high levels of irradiation damage (20--100 displacement per atom or dpa) by the end of life. The data bases and mechanistic understanding of, the degradation of such highly irradiated components, however, are not well established. A key question is the nature of irradiation-assisted intergranular cracking at very high dose, i.e., is it purely mechanical failure or is it stress-commotion cracking? In this work, hot-cell tests and microstructural characterization were performed on Type 304 SS from the hexagonal fuel can of the decommissioned EBR-11 reactor after irradiation to {approximately}50 dpa at {approximately}370 C. Slow-strain-rate tensile tests were conducted at 289 C in air and in water at several levels of electrochemical potential (ECP), and microstructural characteristics were analyzed by scanning and transmission electron microcopies. The material deformed significantly by twinning and exhibited surprisingly high ductility in air, but was susceptible to severe intergranular stress corrosion cracking (IGSCC) at high ECP. Low levels of dissolved O and ECP were effective in suppressing the susceptibility of the heavily irradiated material to IGSCC, indicating that the stress corrosion process associated with irradiation-induced grain-boundary Cr depletion, rather than purely mechanical separation of grain boundaries, plays the dominant role. However, although IGSCC was suppressed, the material was susceptible to dislocation channeling at low ECP, and this susceptibility led to poor work-hardening capability and low ductility.

  12. Caustic ingestion and esophageal function

    Energy Technology Data Exchange (ETDEWEB)

    Cadranel, S.; Di Lorenzo, C.; Rodesch, P.; Piepsz, A.; Ham, H.R. (Children University Hospital, Brussels (Belgium))

    1990-02-01

    The aim of the present study was to investigate esophageal motor function by means of krypton-81m esophageal transit scintigraphy and to compare the results with the functional and morphological data obtained by means of triple lumen manometry and endoscopy. In acute and subacute stages of the disease, all clinical, anatomical, and functional parameters were in good agreement, revealing significant impairment. In chronic stages, the severity of the dysphagia was not correlated to the importance of the residual stenosis. Conversely, 81mKr esophageal transit and manometric's findings were in good agreement with the clinical symptoms, during the entire follow-up period ranging between 3 months to 7 years. The 81mKr test is undoubtedly the easiest and probably the most physiological technique currently available for long-term functional evaluation of caustic esophagitis.

  13. Caustic Soda Will Be Oversupply in 2007

    Institute of Scientific and Technical Information of China (English)

    Yao Liqin

    2007-01-01

    @@ Rapid output increase There are more than 220 caustic soda producers in China today. At the end of 2006 the capacity of caustic soda in China was 17.61 million t/a. The output of caustic soda was 15.118 million tons in 2006, an increase of 19.0% over 2005 and 1.331 million tons were exported, an increase of 55.8%. Production increased fastest in Northwest China, with growth 51.9% faster than 2005. The output in East China grew 22.9% and 22.3% in Southwest China, both higher than the national average level.

  14. Improved stress corrosion cracking resistance of a novel biodegradable EW62 magnesium alloy by rapid solidification, in simulated electrolytes.

    Science.gov (United States)

    Hakimi, O; Aghion, E; Goldman, J

    2015-06-01

    The high corrosion rate of magnesium (Mg) and Mg-alloys precludes their widespread acceptance as implantable biomaterials. Here, we investigated the potential for rapid solidification (RS) to increase the stress corrosion cracking (SCC) resistance of a novel Mg alloy, Mg-6%Nd-2%Y-0.5%Zr (EW62), in comparison to its conventionally cast (CC) counterpart. RS ribbons were extrusion consolidated in order to generate bioimplant-relevant geometries for testing and practical use. Microstructural characteristics were examined by SEM. Corrosion rates were calculated based upon hydrogen evolution during immersion testing. The surface layer of the tested alloys was analyzed by X-ray photoelectron spectroscopy (XPS). Stress corrosion resistance was assessed by slow strain rate testing and fractography. The results indicate that the corrosion resistance of the RS alloy is significantly improved relative to the CC alloy due to a supersaturated Nd enrichment that increases the Nd2O3 content in the external oxide layer, as well as a more homogeneous structure and reduced grain size. These improvements contributed to the reduced formation of hydrogen gas and hydrogen embrittlement, which reduced the SCC sensitivity relative to the CC alloy. Therefore, EW62 in the form of a rapidly solidified extruded structure may serve as a biodegradable implant for biomedical applications.

  15. Fundamental understanding and life prediction of stress corrosion cracking in BWRs and energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Andresen, P.L.; Ford, F.P. [General Electric, Schenectady, NY (United States). Corporate Research and Development Center

    1998-03-01

    The objective of this paper is to present an approach for design and lifetime evaluation of environmental cracking based on experimental and fundamental modeling of the underlying processes operative in crack advance. In detailed this approach and its development and quantification for energy (hot water) systems, the requirements for a life prediction methodology will be highlighted and the shortcomings of the existing design and lifetime evaluation codes reviewed. Examples are identified of its use in a variety of cracking systems, such as stainless steels, low alloy steels, nickel base alloys, and irradiation assisted stress corrosion cracking in boiling water reactor (BWR) water, as well as preliminary use for low alloy steel and Alloy 600 in pressurized water reactors (PWRs) and turbine steels in steam turbines. Identification of the common aspects with environmental cracking in other hot water systems provides a secure basis for its extension to related energy systems. 166 refs., 49 figs.

  16. Chloride stress corrosion cracking of Alloy 600 in boric acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Berge, Ph. [Electricite de France, 92 - Paris la Defense (France); Noel, D.; Gras, J.M.; Prieux, B. [Electricite de France, 77 - Moret-sur-Loing (France). Direction des Etudes et Recherches

    1997-10-01

    The high nickel austenitic alloys are generally considered to have good resistance to chloride stress corrosion cracking. In the standard boiling magnesium chloride solution tests, alloys with more than 40% nickel are immune. Nevertheless, more recent data show that cracking can occur in both Alloys 600 and 690 if the solution is acidified. In other low pH media, such as boric acid solution at 100 deg C, transgranular and intergranular cracking are observed in Alloy 600 in the presence of minor concentrations of sodium chloride (2g/I). In concentrated boric acid at higher temperatures (250 and 290 deg C), intergranular cracking also occurs, either when the chloride concentration is high, or at low chloride contents and high oxygen levels. The role of pH and a possible specific action of boric acid are discussed, together with the influence of electrochemical potential. (author) 21 refs.

  17. Standard Test Method for Stress-Corrosion of Titanium Alloys by Aircraft Engine Cleaning Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method establishes a test procedure for determining the propensity of aircraft turbine engine cleaning and maintenance materials for causing stress corrosion cracking of titanium alloy parts. 1.2 The evaluation is conducted on representative titanium alloys by determining the effect of contact with cleaning and maintenance materials on tendency of prestressed titanium alloys to crack when subsequently heated to elevated temperatures. 1.3 Test conditions are based upon manufacturer's maximum recommended operating solution concentration. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see and .

  18. Localized Deformation as a Primary Cause of Irradiation Assisted Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Gary S. Was

    2009-03-31

    The objective of this project is to determine whether deformation mode is a primary factor in the mechanism of irradiation assisted intergranular stress corrosion cracking of austenitic alloys in light watert reactor core components. Deformation mode will be controlled by both the stacking fault energy of the alloy and the degree of irradiation. In order to establish that localized deformation is a major factor in IASCC, the stacking fault energies of the alloys selected for study must be measured. Second, it is completely unknown how dose and SFE trade-off in terms of promoting localized deformation. Finally, it must be established that it is the localized deformation, and not some other factor that drives IASCC.

  19. Stress corrosion failure of large diameter pressure pipelines of prestressed concrete

    Energy Technology Data Exchange (ETDEWEB)

    Valiente, A. [Universidad Politecnico de Madrid (Spain). Dpto. de Ciencia de Materiales

    2001-07-01

    The failure of a 1.5 m diameter prestressed concrete line for water supply was examined. The water pressure opened a hole of 0.5 m{sup 2} in the pipe wall by breaking the concrete into fragments and by tensile severing of a number of coils of the wire winding. Flexural and tensile testing of samples of the broken materials showed no damage to the concrete, but showed significant losses of strength and ductility in the prestressing steel wire. The SEM analysis of the external and fracture surfaces of the circumferential wires revealed shallow cracking and corroded areas as expected from a stress corrosion cracking process. The failure analysis presented in this paper shows that such a process was able to exhaust the damage tolerance of the affected tube until the pipeline burst under the work pressures. (author)

  20. Modelling of iodine-induced stress corrosion cracking in CANDU fuel

    Science.gov (United States)

    Lewis, B. J.; Thompson, W. T.; Kleczek, M. R.; Shaheen, K.; Juhas, M.; Iglesias, F. C.

    2011-01-01

    Iodine-induced stress corrosion cracking (I-SCC) is a recognized factor for fuel-element failure in the operation of nuclear reactors requiring the implementation of mitigation measures. I-SCC is believed to depend on certain factors such as iodine concentration, oxide layer type and thickness on the fuel sheath, irradiation history, metallurgical parameters related to sheath like texture and microstructure, and the mechanical properties of zirconium alloys. This work details the development of a thermodynamics and mechanistic treatment accounting for the iodine chemistry and kinetics in the fuel-to-sheath gap and its influence on I-SCC phenomena. The governing transport equations for the model are solved with a finite-element technique using the COMSOL Multiphysics® commercial software platform. Based on this analysis, this study also proposes potential remedies for I-SCC.

  1. Stress Corrosion Cracking of Zircaloy-4 in Halide Solutions: Effect of Temperature

    Directory of Open Access Journals (Sweden)

    Farina S.B.

    2002-01-01

    Full Text Available Zircaloy-4 was found to be susceptible to stress corrosion cracking in 1 M NaCl, 1 M KBr and 1 M KI aqueous solutions at potentials above the pitting potential. In all the solutions tested crack propagation was initially intergranular and then changed to transgranular. The effect of strain rate and temperature on the SCC propagation was investigated. An increase in the strain rate was found to lead to an increase in the crack propagation rate. The crack propagation rate increases in the three solutions tested as the temperatures increases between 20 and 90 °C. The Surface-Mobility SCC mechanism accounts for the observation made in the present work, and the activation energy predicted in iodide solutions is similar to that found in the literature.

  2. Caustic graphene plasmons with Kelvin angle

    CERN Document Server

    Shi, Xihang; Gao, Fei; Xu, Hongyi; Yang, Zhaoju; Zhang, Baile

    2015-01-01

    A century-long argument made by Lord Kelvin that all swimming objects have an effective Mach number of 3, corresponding to the Kelvin angle of 19.5 degree for ship waves, has been recently challenged with the conclusion that the Kelvin angle should gradually transit to the Mach angle as the ship velocity increases. Here we show that a similar phenomenon can happen for graphene plasmons. By analyzing the caustic wave pattern of graphene plasmons stimulated by a swift charged particle moving uniformly above graphene, we show that at low velocities of the charged particle, the caustics of graphene plasmons form the Kelvin angle. At large velocities of the particle, the caustics disappear and the effective semi-angle of the wave pattern approaches the Mach angle. Our study introduces caustic wave theory to the field of graphene plasmonics, and reveals a novel physical picture of graphene plasmon excitation during electron energy-loss spectroscopy measurement.

  3. Tunable caustic phenomena in electron wavefields

    Energy Technology Data Exchange (ETDEWEB)

    Tavabi, Amir Hossein, E-mail: a.tavabi@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich (Germany); Migunov, Vadim; Dwyer, Christian; Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich (Germany); Pozzi, Giulio [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich (Germany); Department of Physics and Astronomy, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna (Italy)

    2015-10-15

    Novel caustic phenomena, which contain fold, butterfly and elliptic umbilic catastrophes, are observed in defocused images of two approximately collinear oppositely biased metallic tips in a transmission electron microscope. The observed patterns depend sensitively on defocus, on the applied voltage between the tips and on their separation and lateral offset. Their main features are interpreted on the basis of a projected electrostatic potential model for the electron-optical phase shift. - Highlights: • Electron-optical caustics are observed in defocused images of biased metallic tips. • The caustics depend on defocus, on the bias between the tips and on their separation. • The setup offers the flexibility to study a wide variety of caustic phenomena.

  4. Dissolution of copper in chloride/ammonia mixtures and the implications for the stress corrosion cracking of copper containers

    Energy Technology Data Exchange (ETDEWEB)

    King, F.; Greidanus, G.; Jobe, D.J

    1999-05-01

    Stress-corrosion cracking is a possible failure mechanism for copper nuclear fuel waste disposal containers. One species known to cause the stress corrosion of copper alloys is ammonia. It is conceivable that ammonia could be produced in a disposal vault under certain, very specific conditions. There are a number of conditions, however, that mitigate against container failure by stress corrosion, one of which is the presence of chloride ions in deep Canadian Shield groundwaters. There are a number of reports in the literature that suggest that Cl{sup -} has an inhibitive effect on the stress corrosion of Cu alloys in ammonia solutions. The electrochemical behaviour of Cu in Cl{sup -}/ammonia solutions has been studied as a function of ammonia concentration, pH, the rate of mass transport and electrochemical potential. In particular, the effects of these parameters on the formation Of Cu{sub 2}O films and the steady-state dissolution behaviour have been determined. All experiments were carried out in 0.1 mol{center_dot}dm{sup -3} NaC1 as a base solution. A series of aqueous speciation and equilibrium potential/pH diagrams are also presented for the quaternary system Cu-C1{sup -}NH{sub 3}/NH{sub 4{sup +}}H{sub 2}O. These diagrams are used to interpret the results of the electrochemical experiments reported here. In addition, it is demonstrated how these diagrams could be used to predict the time-dependence of the susceptibility to stress corrosion cracking of Cu containers in a disposal vault. (author)

  5. Factors affecting stress assisted corrosion cracking of carbon steel under industrial boiler conditions

    Science.gov (United States)

    Yang, Dong

    Failure of carbon steel boiler tubes from waterside has been reported in the utility boilers and industrial boilers for a long time. In industrial boilers, most waterside tube cracks are found near heavy attachment welds on the outer surface and are typically blunt, with multiple bulbous features indicating a discontinuous growth. These types of tube failures are typically referred to as stress assisted corrosion (SAC). For recovery boilers in the pulp and paper industry, these failures are particularly important as any water leak inside the furnace can potentially lead to smelt-water explosion. Metal properties, environmental variables, and stress conditions are the major factors influencing SAC crack initation and propagation in carbon steel boiler tubes. Slow strain rate tests (SSRT) were conducted under boiler water conditions to study the effect of temperature, oxygen level, and stress conditions on crack initation and propagation on SA-210 carbon steel samples machined out of boiler tubes. Heat treatments were also performed to develop various grain size and carbon content on carbon steel samples, and SSRTs were conducted on these samples to examine the effect of microstructure features on SAC cracking. Mechanisms of SAC crack initation and propagation were proposed and validated based on interrupted slow strain tests (ISSRT). Water chemistry guidelines are provided to prevent SAC and fracture mechanics model is developed to predict SAC failure on industrial boiler tubes.

  6. In vivo oxide-induced stress corrosion cracking of Ti-6Al-4V in a neck-stem modular taper: Emergent behavior in a new mechanism of in vivo corrosion.

    Science.gov (United States)

    Gilbert, Jeremy L; Mali, Sachin; Urban, Robert M; Silverton, Craig D; Jacobs, Joshua J

    2012-02-01

    In vivo modular taper corrosion in orthopedic total joint replacements has been documented to occur for head-neck tapers, modular-body tapers, and neck-stem tapers. While the fretting corrosion mechanism by which this corrosion occurs has been described in the literature, this report shows new and as yet unreported mechanisms at play. A retrieved Ti-6Al-4V/Ti-6Al-4V neck-stem taper interface, implanted for 6 years is subjected to failure analysis to document taper corrosion processes that lead to oxide driven crack formation on the medial side of the taper. Metallurgical sectioning techniques and scanning electron microscopy analysis are used to document the taper corrosion processes. The results show large penetrating pitting attack of both sides of the taper interface where corrosion selectively attacks the beta phase of the microstructure and eventually consumes the alpha phase. The pitting attack evolves into plunging pits that ultimately develop into cracks where the crack propagation process is one of corrosion resulting in oxide formation and subsequent reorganization. This process drives open the crack and advances the front by a combination of oxide-driven crack opening stresses and corrosion attack at the tip. The oxide that forms has a complex evolving structure including a network of transport channels that provide access of fluid to the crack tip. This emergent behavior does not appear to require continued fretting corrosion to propagate the pitting and cracking. This new mechanism is similar to stress corrosion cracking where the crack tip stresses arise from the oxide formation in the crack and not externally applied tensile stresses.

  7. Electrochemical investigation on the hydrogen permeation behavior of 7075-T6 Al alloy and its influence on stress corrosion cracking

    Science.gov (United States)

    Zheng, Chuan-bo; Yan, Bing-hao; Zhang, Ke; Yi, Guo

    2015-07-01

    The hydrogen permeation behavior and stress corrosion cracking (SCC) susceptibility of precharged 7075-T6 Al alloy were investigated in this paper. Devanthan-Stachurski (D-S) cell tests were used to measure the apparent hydrogen diffusivity and hydrogen permeation current density of specimens immersed in 3.5wt% NaCl solution. Electrochemical experiment results show that the SCC susceptibility is low during anodic polarization. Both corrosion pits and hydrogen-induced cracking are evident in scanning electron microscope images after the specimens have been charging for 24 h.

  8. Influence factors on stress corrosion cracking of P110 tubing steel under CO2 injection well annulus environment

    Institute of Scientific and Technical Information of China (English)

    刘然克; 贾静焕; 杜翠薇; 李晓刚

    2016-01-01

    Stress corrosion cracking (SCC) behavior of P110 tubing steel in simulated CO2 injection well annulus environments was investigated through three-point bent tests, potentiodynamic polarization and EIS measurements. The results demonstrate that SCC of P110 tubing steel could occur in acidulous simulated environment, and the sensitivity of SCC increases with the decrease of pH, as well as increase of sulfide concentration and total environmental pressure. Both anodic dissolution and hydrogen embrittlement make contributions to the SCC. Adequate concentration of corrosion inhibitor can inhibit the occurrence of SCC on account of the inhibition of localized anodic dissolution and cathodic hydrogen evolution.

  9. Stress corrosion of unalloyed steels in geological storage conditions; Corrosion sous contrainte des aciers non allies dans les conditions du stockage geologique

    Energy Technology Data Exchange (ETDEWEB)

    Didot, A.; Herms, E.; Bataillon, C.; Chene, J. [CEA Saclay, Dept. de Physico-Chimie (DEN/DANS/DPC/SCCME/LECA), 91 - Gif sur Yvette (France); Crusset, D. [Agence Nationale pour la Gestion des Dechets Radioactifs (ANDRA), 92 - Chatenay Malabry (France)

    2007-07-01

    The concept retained for high level and years living radioactive waste disposal is the underground storage. It is then necessary to know the behaviour in time (about 10000 years) of the different constituent elements of the containment. The storage site chosen is the Bures' ones, presenting a clay formation at 600 m of depth. Each compartment is separated of a sufficient distance in order to profit of the thermal dispersion effect in the rock for optimizing the cooling of the package. In this work, has been used an unalloyed steel sur-container. The aim is to understand the resistance of the material under corrosion and loading, and particularly the stress corrosion which is a particular case of cracking assisted by environment. The material studied is a weld of two unalloyed steels obtained by electron beam. Slow traction tests have been carried out in an autoclave in the following experimental conditions: interstitial water in equilibrium with a helium-CO{sub 2} mixture 5.4 per thousand under 50 bar and at a temperature of 90 C. The results show an influence of the hydrogen corrosion on the mechanical behaviour of the material and particularly a decrease of the size of the reduction in area, which is practically unexisting in the case of the melted zone. These results are explained into details. (O.M.)

  10. Stress Corrosion Cracking in Al-Zn-Mg-Cu Aluminum Alloys in Saline Environments

    Science.gov (United States)

    Holroyd, N. J. Henry; Scamans, G. M.

    2013-03-01

    Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack ("pop-in" vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies ( E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (alloys (>~0.8 wt pct), they are typically

  11. Stress Corrosion Crack Growth Behavior of Titanium Alloy/Bioactive Glasses Sandwiches in Simulated Human Physiological Environment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion crack growth(SCCG) behavior of their interfaces with Ti6Al4V was investigated in simulated body fluid (SBF) with the objectiveof discerning the salient mechanisms of crack advance and to assess the reliability of the bonds. Results indicatedthat crack growth rates in Ti6Al4V/glass/Ti6Al4V sandwich specimens were nearly the same as or slightly lowerthan those in the bulk glasses at comparable stress intensities; indeed, cracks would prefer to propagate off theinterface, suggesting that the Ti6Al4V/glass interface has relatively good crack-growth resistance. Mechanistically,interfacial crack growth appears to be controlled by the classic stress corrosion mechanisms for silicate glasses, withno discernible effect of bioactivity on the SCCG behavior being observed.

  12. Influence of Tensile Stresses on α+β – Titanium Alloy VT22 Corrosion Resistance in Marine Environment

    Directory of Open Access Journals (Sweden)

    Yu. A. Puchkov

    2015-01-01

    Full Text Available Tensile stresses and hydrogen render strong influence on the titanic alloys propensity for delayed fracture. The protective film serves аs a barrier for penetration in hydrogen alloy. Therefore to study the stress effect on its structure and protective properties is of significant interest.The aim of this work is to research the tensile stress influence on the passivation, indexes of corrosion, protective film structure and reveal reasons for promoting hydrogenation and emerging propensity for delayed fracture of titanium alloy VТ22 in the marine air atmosphere.The fulfillеd research has shown that:- there is а tendency to reduce the passivation abilities of the alloy VТ22 in synthetic marine water (3 % solution of NaCl with increasing tensile stresses up to 1170 МPа, namely to reduce the potential of free corrosion and the rate of its сhange, thus the alloy remains absolutely (rather resistant;- the protective film consists of a titanium hydroxide layer under which there is the titanium oxide layer adjoining to the alloy, basically providing the corrosion protection.- the factors providing hydrogenation of titanium alloys and formation in their surface zone fragile hydrides, causing the appearing propensity for delayed fracture, alongside with tensile stresses are:- substances promoting chemisorbtion of hydrogen available in the alloy and on its surface;- the cathodic polarization caused by the coupling;- the presence of the structural defects promoting the formation of pitting and local аcidifying of the environment surrounding the alloy.

  13. Electrochemical Behavior and Stress Corrosion Sensitivity of X70 Steel Under Disbonded Coatings in Korla Soil Solution

    Science.gov (United States)

    Qian, Hongchang; Wang, Luntao; Wang, Huiru; Zheng, Wenru; Zhang, Dawei; Du, Cuiwei

    2016-09-01

    The corrosion of X70 pipeline steel under a model disbonded coating was studied in a simulated solution of Korla soil by combining in situ electrochemical measurements at different locations in the crevice and stress corrosion cracking (SCC) sensitivity analyses in the corresponding simulated environments. The results from electrochemical impedance spectroscopy showed that the corrosion product resistance R t and charge transfer resistance R ct of X70 steel first increased and then decreased with increasing distance from the opening of the crevice in the disbonded coating. Scanning electron micrographs showed that pitting in the crevice became more severe at deeper locations in the crevice. Slow strain rate tests showed that the lowest SCC sensitivity of X70 steel was found at 15 cm away from the opening, and the highest SCC sensitivity was at the end of the crevice.

  14. Electrochemical and Sulfide Stress Corrosion Cracking Behaviors of Tubing Steels in a H2S/CO2 Annular Environment

    Science.gov (United States)

    Liu, Z. Y.; Wang, X. Z.; Liu, R. K.; Du, C. W.; Li, X. G.

    2014-04-01

    The electrochemical and sulfide stress corrosion cracking (SSCC) behaviors of 13Cr stainless steel and P110 steel were investigated in a simulated acidic annular environment with low-temperature and high-pressure H2S/CO2 using electrochemical methods, U-bend immersion tests, and scanning electron microscopy. In the solution containing high pressure CO2, 13Cr, and P110 steels exhibited general corrosion and severe pitting, respectively. Compared with sweet corrosion, additional H2S in the solution enhanced the corrosion of 13Cr steel but inhibited the corrosion of P110 steel. By contrast, in a solution containing 4 MPa CO2 and different (0-0.3 MPa), the susceptibility of both 13Cr stainless steel and P110 steel toward SSCC was significantly promoted by increases in H2S partial pressure. The 13Cr stainless steel exhibited higher susceptibility toward SSCC than P110 steel under a H2S/CO2 environment but lower susceptibility under a pure CO2 environment.

  15. Numerical investigation on stress corrosion cracking behavior of dissimilar weld joints in pressurized water reactor plants

    Directory of Open Access Journals (Sweden)

    Lingyan Zhao

    2014-07-01

    Full Text Available There have been incidents recently where stress corrosion cracking (SCC observed in the dissimilar metal weld (DMW joints connecting the reactor pressure vessel (RPV nozzle with the hot leg pipe. Due to the complex microstructure and mechanical heterogeneity in the weld region, dissimilar metal weld joints are more susceptible to SCC than the bulk steels in the simulated high temperature water environment of pressurized water reactor (PWR. Tensile residual stress (RS, in addition to operating loads, has a great contribution to SCC crack growth. Limited experimental conditions, varied influence factors and diverging experimental data make it difficult to accurately predict the SCC behavior of DMW joints with complex geometry, material configuration, operating loads and crack shape. Based on the film slip/dissolution oxidation model and elastic-plastic finite element method (EPFEM, an approach is developed to quantitatively predict the SCC growth rate of a RPV outlet nozzle DMW joint. Moreover, this approach is expected to be a pre-analytical tool for SCC experiment of DMW joints in PWR primary water environment.

  16. Public inquiry concerning stress corrosion cracking on Canadian oil and gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Vollman, K.W.; Cote-Verhaaf, A.; Illing, R.

    1996-11-01

    An comprehensive inquiry was conducted into the serious problem of near-neutral pH stress corrosion cracking (SCC) in Canada`s buried oil and gas pipelines. The inquiry was prompted by evidence of the widespread nature of SCC and awareness that research was producing new insights into the problem. Two major ruptures and fires occurred on the TransCanada system in February and July of 1995. The July rupture was in a location where it was believed SCC could not occur. SCC on pipelines occurs when small cracks develop on the outside surface of the buried pipeline. With time the cracks grow large enough until the pipeline fails or ruptures. SCC results from an interaction of the following three conditions: a potent environment at the pipe surface, a susceptible pipe material, and a tensile stress. Recommendations to resolve the problem included implementation of an SCC management program by pipeline companies, changes to the design of the pipeline, continued research, establishment of an SCC database, improved emergency response practices, and information sharing. 84 refs., 8 tabs., 67 figs.

  17. Prevention of stress-corrosion cracking in nuclear waste storage tanks

    Energy Technology Data Exchange (ETDEWEB)

    Ondrejcin, R S

    1984-01-01

    Stress corrosion cracking (SCC) has occurred in the early versions of carbon steel primaries of nuclear waste tanks at the Savannah River Plant. (Secondary containment was provided by a vessel surrounding the lower portion of the primary tank.) Evaporated alkaline nitrate wastes in the form of crystallized salts are being dissolved from some of these tanks for transfer to new tanks of a different design. To prevent the SCC sequence from occurring during salt dissolution, the levels of inhibitors required to prevent cracking at yield stresses were determined. Special statistically designed experiments were performed to evaluate the probability of cracking under the combined influences of nitrate, nitrite, hydroxide, and temperature. Experimentlly, samples were tested by a potentially controlled constant extension rate test and by wedge opening loaded samples. Two equations were derived by multivariable regression analyses that correlated probability of cracking as the dependent variable to nitrate, nitrite, and hydroxide concentrations and temperature as the independent variables. From these equations, simple operating standards were developed by setting the probability of cracking equal to zero and solving for the four independent variables. 15 references, 15 figures, 8 tables.

  18. Near-neutral pH Stress Corrosion Crack Initiation under Simulated Coating Disbondment

    Science.gov (United States)

    Eslami, Abdoulmajid

    This research is aimed at understanding near-neutral pH SCC initiation under disbonded coatings of pipeline steels, and the effect of different environmental and operational factors on crack initiation. Understanding near-neutral pH stress corrosion cracking (SCC) could answer many of the primary questions on crack initiation of SCC which have not yet been answered. It could also assist the development of effective mitigative measures dealing with thousands of kilometer of pipelines containing this form of cracking, in addition to preventive action for future pipeline installations. Near-neutral pH SCC usually occurs under polyethylene tape (PE tape) coated pipelines, at locations where the coating becomes disbonded and/or damaged. Ground water can then penetrate under the damaged/disbonded coating, become trapped and form a suitable environment for corrosion and cracking. Despite extensive studies on this topic the details of crack initiation mechanisms in addition to the exact role of environmental and operational factors on crack initiation are not thoroughly understood. Most previous laboratory tests have been done in aggressive loading conditions and ignored the effect of coatings and cathodic protections (CP). In order to simulate the conditions responsible for crack initiation, a novel testing setup capable of simulating the synergistic effects of coating disbondment, cathodic protection and cyclic loading was implemented. Using this setup and long term laboratory tests near-neutral pH SCC initiation mechanisms and the effect of some environmental and operational factors on crack initiation were investigated. It was found that near-neutral pH SCC initiation does not necessarily occur in near-neutral pH environments as commonly believed. Depending on the level of CP and CO2 in the underground environment, different localized environments with varying pH values from near-neutral to high values above 10 can form under the disbonded coatings. This significantly

  19. Pigging ends freezeups in caustic piping system

    Energy Technology Data Exchange (ETDEWEB)

    Gros, R.; Gaines, A.

    1985-03-01

    Convent Chemical Corporation in Convent, LA produces and ships bulk quantities of chlorine and caustic soda (NaOH). The caustic soda is available in various grades, including a 50% aqueous solution that freezes at 56/sup 0/F. An extensive network of chemical-resistant polypropylene-lined steel pipe (without heat tracing) is used to transfer the caustic soda from the production area to storage tanks and to the loading facilities for tank trucks, rail tank cars and barges. A sudden drop in ambient temperature can cause freezeup of the caustic transfer pipes which may result in downtime of as much as a week. Convent plant engineers designed a pigging system for the outdoor caustic transfer lines in the tank farm and to the loading stations. The patented design pig, (internal pipeline cleaner) consists of a flexible, bullet-shaped cylinder of chemical-resistant polyurethane foam with strips of urethane rubber on the surface, or with a solid coating of the tough material. Fluid or gas pressure on the sealed concave base propels the flexible pig through the pipe, valves, elbows, and other fittings, and material ahead of the pig is discharged into an appropriate receiver. The pigging system has eliminated the caustic freezing and plugging problems since it was installed in the summer of 1981. The flexible pig, propelled by 80 psi air, is used to clear the pipelines whenever caustic is transferred during the winter months. The air-propelled pig is designed and sized to easily pass through restrictions in the piping system, such as reduced port plug valves, but was once stuck when it reached a section of pipe that had collapsed. A pig containing the Cobalt 60 nuclear element was inserted into the line to quickly locate the stuck pig with the Geiger counter. The faulty section of pipe was replaced with a new polypropylene lined spool piece.

  20. The susceptibility of 90Cu-10Ni alloy to stress corrosion cracking in seawater polluted by sulfide ions

    Science.gov (United States)

    Domiaty, A. El; Alhajji, J. N.

    1997-08-01

    Electrochemical polarization measurements and slow strain rate tests (SSRT) of a 90Cu-10Ni alloy in highly sulfide polluted seawater were conducted to investigate stress-corrosion cracking (SCC) behavior. The severity of the SCC depends on the sulfide concentration in the seawater. The severity increases as the concentration increases. Because the major time in SCC is spent in the initiation process of the propagating crack, the fracture toughness has only a minor effect in the component life failed by SCC. The SCC behavior of CDA706 is strictly linked to sulfide concentration in the range of 100 to 1000 ppm. The general corrosion of Cu-Ni alloys in low (100 ppm) sulfide polluted seawater increases due to the selective copper dissolution. Cyclic polarization measurements confirmed that the corrosion rate decreases slightly as the sulfide concentration increases. Pitting tendency was high in the low concentration range of sulfide and low in the high concentration range. The presence of stresses in SCC removes the protective layer as it increases during testing of the specimen or during the actual service of a component. The authors propose that film rupture occurred, and two proposed SCC mechanisms were operational, namely sulfide stress cracking associated with the anodic dissolution in the low sulfide concentration range and hydrogen embrittlement, which was dominant in the high sulfide concentration range. It was found that a synergism exists between sulfide and stress that enhances the effect of the latter.

  1. Irradiation-assisted stress corrosion cracking behavior of austenitic stainless steels applicable to LWR core internals.

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Shack, W. J.; Energy Technology

    2006-01-31

    This report summarizes work performed at Argonne National Laboratory on irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steels that were irradiated in the Halden reactor in simulation of irradiation-induced degradation of boiling water reactor (BWR) core internal components. Slow-strain-rate tensile tests in BWR-like oxidizing water were conducted on 27 austenitic stainless steel alloys that were irradiated at 288 C in helium to 0.4, 1.3, and 3.0 dpa. Fractographic analysis was conducted to determine the fracture surface morphology. Microchemical analysis by Auger electron spectroscopy was performed on BWR neutron absorber tubes to characterize grain-boundary segregation of important elements under BWR conditions. At 0.4 and 1.4 dpa, transgranular fracture was mixed with intergranular fracture. At 3 dpa, transgranular cracking was negligible, and fracture surface was either dominantly intergranular, as in field-cracked core internals, or dominantly ductile or mixed. This behavior indicates that percent intergranular stress corrosion cracking determined at {approx}3 dpa is a good measure of IASCC susceptibility. At {approx}1.4 dpa, a beneficial effect of a high concentration of Si (0.8-1.5 wt.%) was observed. At {approx}3 dpa, however, such effect was obscured by a deleterious effect of S. Excellent resistance to IASCC was observed up to {approx}3 dpa for eight heats of Types 304, 316, and 348 steel that contain very low concentrations of S. Susceptibility of Types 304 and 316 steels that contain >0.003 wt.% S increased drastically. This indicates that a sulfur related critical phenomenon plays an important role in IASCC. A sulfur content of <0.002 wt.% is the primary material factor necessary to ensure good resistance to IASCC. However, for Types 304L and 316L steel and their high-purity counterparts, a sulfur content of <0.002 wt.% alone is not a sufficient condition to ensure good resistance to IASCC. This is in distinct contrast to

  2. Probing dark matter caustics with weak lensing

    CERN Document Server

    Gavazzi, R; Fort, B; Gavazzi, Raphael; Mohayaee, Roya; Fort, Bernard

    2006-01-01

    Caustics are high-density structures that form frequently in collisionless media. Under self-gravity, cold dark matter flows focus onto caustics which are yet to be resolved in numerical simulations and or observed in the real world. If detected, caustics would provide a strong evidence for dark matter and would rule out alternative models such as those with modified dynamics. Here, we demonstrate how they might be observed in the weak lensing data. We evaluate the shear distortion and show that its radial profile is marked by a characteristic sawtooth pattern due to the caustics in dark matter haloes that form by selfsimilar accretion. We discuss the observational complications, mainly due to the poor knowledge of the virial radii of the haloes and demonstrate that a superposition of about 600 cluster-size haloes would give a signal-to-noise ratio which is sufficiently large for the detection of caustics with ground-based observations. This number is reduced to 200 for space-based observations. These bounds ...

  3. Line Caustic Microlensing and Limb Darkening

    CERN Document Server

    Rhie, S H; Rhie, Sun Hong; Bennett, David P.

    1999-01-01

    In a line caustic crossing microlensing event, the caustic line moving across the surface of the source star provides a direct method to measure the integrated luminosity profile of the star. Combined with the enormous brightening at the caustic crossings, microlensing offers a promising tool for studying stellar luminosity profiles. We derive the amplification behavior of the two extra images that become partial images conjoined across the critical curve at a line caustic crossing. We identify the multiplicative factors that depend on the caustic crossing point and the relative size of the star, and the shape function that depends on the stellar luminosity profile. We examine the analytic limb-darkening models -- linear, square root, and square -- using the analytic form of the shape function. We find that the microlensing lightcurves must be determined to an accuracy of better than 0.3-0.8% in order to be able to determine the linear limb-darkening parameter $c_1$ with precision of binaries as reported by P...

  4. MICROSTRUCTURE NEAR SCRATCH ON ALLOY 690TT AND STRESS CORROSION INDUCED BY SCRATCHING%690TT合金划痕显微组织及划伤诱发的应力腐蚀

    Institute of Scientific and Technical Information of China (English)

    孟凡江; 王俭秋; 韩恩厚; 庄子哲雄; 柯伟

    2011-01-01

    测试表明,690TT合金划痕周围形成了加工硬化区,范围可达100 μm.TEM及EBSD-OIM组织观察发现,划痕沟槽处的基体组织出现了一定程度的纳米化.在330℃碱溶液中的浸泡实验表明,划伤诱发了690TT合金应力腐蚀裂纹的萌生和扩展,划伤过程中形成的变形晶界、孪晶界以及产生的微观裂纹成为应力腐蚀裂纹优先萌生的位置.Pb的存在使氧化膜变得疏松,加速了基体的溶解和氧化.随着溶液中Pb含量的增加,划伤诱发的应力腐蚀裂纹长度随之增加.690TT合金表面划伤严重降低了材料抵抗应力腐蚀开裂的能力.%The microstructure and stress corrosion cracking (SCC) behavior of scratched zone on alloy 690TT were studied by using microhardness, TEM, EBSD-OIM and immersion experiment in caustic solution. It was found that a deformed hardening layer with a dimension range of 100 /xm was produced near the scratch. TEM and EBSD-OIM observations showed that the grains at shallow surface of scratch groove were refined to nano-size. SCC tests for scratched alloy 690TT were performed in caustic solution at high temperature with or without addition of lead oxides. The results showed that SCC cracks initiated and propagated at scratch banks and scratch grooves. Grain boundaries, twin boundaries deformed and microcracks produced during scratching process are preferential sites for SCC. The oxide films formed on scratch groove were loosed by lead. The SCC crack length increased with increase of lead content. Scratched alloy 690TT is susceptible to SCC.

  5. INTER-CONTACT FORCE ANALYSIS OF IMPACTED DISK ASSEMBLY BY DYNAMIC CAUSTICS

    Institute of Scientific and Technical Information of China (English)

    LI Ming(李明); ZHANG Jue; FANG Jing(方竞)

    2003-01-01

    The caustic method was utilized to study the contact force transmission in disk assemblies under impact load. The mapping equations were obtained based on the first invariant of the stress components in the disk subject to a normal concentrated force, and a characteristic dimension of the maximum size in the caustic curve was proposed to evaluate the contact force between the disks.Transient patterns of the caustic shadows were recorded by means of a high-speed camera of off-focus imaging, then the histories of the inter-contact forces among the disks were obtained with respect to the conditions of different masses and heights of the falling hammers. The influence of the impact loading and impulsive velocity was analyzed with respect to the force responses of the disk assembly,the double-peak phenomenon with comparison to the initial masses, and the energy dissipation of the systems under impact of different momentums.

  6. Flaw growth of 7075, 7475, 7050 and 7049 aluminum alloy plate in stress corrosion environments: 4-year marine atmosphere results

    Science.gov (United States)

    Hasse, K. R.; Dorward, R. C.

    1981-01-01

    After nearly 53 months of exposure to marine atmosphere, crack growth in SL DCB specimens from 7075, 7475, 7050, and 7049-T7X plate has slowed to the arbitrary 10 to the -10 power m/sec used to define threshold stress intensity. Because some specimens appear to be approaching crack arrest, the importance of self-loading from corrosion product wedging as a significant driving force for crack propagation in overaged materials is questioned. Crack length-time data were analyzed using a computer curve fitting program which minimized the effects of normal data scatter, and provided a clearer picture of material performance. Precracked specimen data are supported by the results of smooth specimen tests. Transgranular stress corrosion cracking was observed in TL DCB specimens from all four alloys. This process is extremely slow and is characterized by a striated surface morphology.

  7. Report on Status of Shipment of High Fluence Austenitic Steel Samples for Characterization and Stress Corrosion Crack Testing

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Scarlett R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    The goal of the Mechanisms of Irradiation Assisted Stress Corrosion Cracking (IASCC) task in the LWRS Program is to conduct experimental research into understanding how multiple variables influence the crack initiation and crack growth in materials subjected to stress under corrosive conditions. This includes understanding the influences of alloy composition, radiation condition, water chemistry and metallurgical starting condition (i.e., previous cold work or heat treatments and the resulting microstructure) has on the behavior of materials. Testing involves crack initiation and growth testing on irradiated specimens of single-variable alloys in simulated Light Water Reactor (LWR) environments, tensile testing, hardness testing, microstructural and microchemical analysis, and detailed efforts to characterize localized deformation. Combined, these single-variable experiments will provide mechanistic understanding that can be used to identify key operational variables to mitigate or control IASCC, optimize inspection and maintenance schedules to the most susceptible materials/locations, and, in the long-term, design IASCC-resistant materials.

  8. Performance of NiB inhibitor for PbSCC of alloy 600 in Pb-contaminated water and caustic solutions

    Science.gov (United States)

    Kim, Joung Soo; Yi, Yong-Sun; Kwon, Oh Chul; Kim, Mi-Ae; Kim, Hong Pyo

    2008-06-01

    Nickel-based iron-chromium alloys are used as steam generator (SG) tubing materials in nuclear power plants (NPPs) but experience intergranular stress corrosion cracking (IGSCC) and lead stress corrosion cracking (PbSCC) due to the harsh operating conditions of NPPs. In order to improve the integrity of SGs, many studies have sought suitable inhibitors for IGSCC, while those for PbSCC have been sought to a limited extent. In this study, the performance of nickel boride (NiB) as an inhibitor for PbSCC was evaluated. Nickel boride has been shown to be a good inhibitor for IGSCC of Alloy (or Inconel) 600 in a caustic aqueous solution containing no lead (Pb). No significant SCC was observed to occur in Alloy 600 tested in pure water under the slow strain rate test (SSRT) condition in this study. A mixed mode of IGSCC and TGSCC, however, occurred relatively easily in Alloy 600 tested in pure water containing lead oxide (PbO) at 315 °C. The susceptibility of Alloy 600 to SCC decreased with the addition of NiB, implying that NiB can be used as an inhibitor for PbSCC in Pb-contaminated water.

  9. Research of stress corrosion cracking of T225NG titanium alloy in loop water of high temperature and high pressure

    Institute of Scientific and Technical Information of China (English)

    Xu Jijin; Yan Keng; Chen Ligong; Jiang Chengyu

    2006-01-01

    Double cantilever beam (DCB) specimens were used to research the stress corrosion cracking of T225NG titanium alloy in loop water of high temperature and high pressure. DCB specimens were forced pre-stress, put into high pressure autoclave, and the stress corrosion and crack expansion of specimens were observed and measured in 500 h, 1 000 h and 2 000h respectively. The results show that small expansion occurred along the direction of pre-cracking. According to calculation,the speed of cracking expansion is lower than 10 -9 m/s in 500 h and the value of KIscc/KI is higher than 0. 75, which proves that T225NG has an excellent corrosion resistance in loop water. The main reason is that there is an oxide film on the surface of specimens. According to the analysis of energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), the oxide film consists of TiO2. Therefore, the oxide film at the crack tip impedes the hydrogen separating out from the cathode to penetrate into titanium alloy and resists hydrogen embrittlement.

  10. Test Results for Caustic Demand Measurements on Tank 241-AX-101 and Tank 241-AX-103 Archive Samples

    Energy Technology Data Exchange (ETDEWEB)

    Doll, Stephanie R. [Washington River Protection Solutions, Richland, WA (United States); Bolling, Stacie D. [Washington River Protection Solutions, Richland, WA (United States)

    2016-07-14

    Caustic demand testing is used to determine the necessary amount of caustic required to neutralize species present in the Hanford tank waste and obtain a target molarity of free hydroxide for tank corrosion control. The presence and quantity of hydroxide-consuming analytes are just as important in determining the caustic demand as is the amount of free hydroxide present. No single data point can accurately predict whether a satisfactory hydroxide level is being met, as it is dependent on multiple factors (e.g., free hydroxide, buffers, amphoteric metal hydroxides, bicarbonate, etc.). This enclosure contains the caustic demand, scanning electron microscopy (SEM), polarized light microscopy (PLM), and X-ray diffraction (XRD) analysis for the tank 241-AX-101 (AX-101) and 241-AX-103 (AX-103) samples. The work was completed to fulfill a customer request outlined in the test plan, WRPS-1505529, “Test Plan and Procedure for Caustic Demand Testing on Tank 241-AX-101 and Tank 241-AX-103 Archive Samples.” The work results will provide a baseline to support planned retrieval of AX-101 and AX-103.

  11. Test Results for Caustic Demand Measurements on Tank 241-AX-101 and Tank 241-AX-103 Archive Samples

    Energy Technology Data Exchange (ETDEWEB)

    Doll, Stephanie R. [Washington River Protection Solutions, Richland, WA (United States); Bolling, Stacie D. [Washington River Protection Solutions, Richland, WA (United States)

    2016-07-14

    Caustic demand testing is used to determine the necessary amount of caustic required to neutralize species present in the Hanford tank waste and obtain a target molarity of free hydroxide for tank corrosion control. The presence and quantity of hydroxide-consuming analytes are just as important in determining the caustic demand as is the amount of free hydroxide present. No single data point can accurately predict whether a satisfactory hydroxide level is being met as it is dependent on multiple factors (e.g., free hydroxide, buffers, amphoteric metal hydroxides, bicarbonate, etc.). This enclosure contains the caustic demand, scanning electron microscopy (SEM), polarized light microscopy (PLM), and X-ray diffraction (XRD) analysis for the tank 241-AX-101 (AX-101) and 241-AX-103 (AX-103) samples. The work was completed to fulfill a customer request outlined in the test plan, WRPS-1505529, “Test Plan and Procedure for Caustic Demand Testing on Tank 241-AX-101 and Tank 241-AX-103 Archive Samples.” The work results will provide a baseline to support planned retrieval of AX-101 and AX-103.

  12. A state of the art on primary side stress corrosion cracking in nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. P.; Kim, J. S.; Han, J. H.; Lee, D. H.; Lim, Y. S.; Suh, J. H.; Hwang, S. S.; Hur, D. H

    1999-09-01

    A state of art on primary water stress corrosion cracking (PWSCC) of alloy 600 used as steam generator tubing of nuclear power plant and remedial action on the PWSCC were reviewed and analyzed. One of the major metallurgical factors which have effect on PWSCC is Cr carbide distribution. A semicontinuous intergranular Cr carbide distribution enhance PWSCC of alloy 600. PWSCC rate is reported to be reported to be proportional to exp(-50 cal/RT) {sigma}{sup 4}. PWSCC rate also increase with increase in hydrogen partial pressure from 0 to 150 ppm and then decreased with further increase in hydrogen partial pressure to 757 ppm. Development of PWSCC prediction technology which takes into account tubing material, fabrication process and operating history of steam generator is needed to manage PWSCC of domestic nuclear power plant. PWSCC has mainly occurred at expansion irregularities within tubesheet, expansion transitions, dented tube support plate intersections and transition and apex of U bend. Remedial actions to PWSCC are sleeving, plugging, temperature reduction, Ni plating, Ni sleeving, shot peening and steam generator replacement in worst case. Option to remedial actions depend on plant specific such as plant age, leak rate from primary to secondary, density and progression of PWSCC. Ni sleeving developed in Framatome seems to be a powerful method because it never subject to PWSCC. Remedial action should be developed and evaluated for possible PWSCC of domestic nuclear power plant. (author)

  13. Stress corrosion cracking of alloy 600 using the constant strain rate test

    Energy Technology Data Exchange (ETDEWEB)

    Bulischeck, T. S.; van Rooyen, D.

    1980-01-01

    The most recent corrosion problems experienced in nuclear steam generators tubed with Inconel alloy 600 is a phenomenon labeled ''denting''. Denting has been found in various degrees of severity in many operating pressurized water reactors. Laboratory investigations have shown that Inconel 600 exhibits intergranular SCC when subjected to high stresses and exposed to deoxygenated water at elevated temperatures. A research project was initiated at Brookhaven National Laboratory in an attempt to improve the qualitative and quantitative understanding of factors influencing SCC in high temperature service-related environments. An effort is also being made to develop an accelerated test method which could be used to predict the service life of tubes which have been deformed or are actively denting. Several heats of commercial Inconel 600 tubing were procured for testing in deaerated pure and primary water at temperatures from 290 to 365/sup 0/C. U-bend type specimens were used to determine crack initiation times which may be expected for tubes where denting has occurred but is arrested and provide baseline data for judging the accelerating effects of the slow strain rate method. Constant extension rate tests were employed to determine the crack velocities experienced in the crack propagation stage and predict failure times of tubes which are actively denting. 8 refs., 17 figs., 5 tabs.

  14. Reconstruction of stress corrosion cracks using signals of pulsed eddy current testing

    Science.gov (United States)

    Wang, Li; Xie, Shejuan; Chen, Zhenmao; Li, Yong; Wang, Xiaowei; Takagi, Toshiyuki

    2013-06-01

    A scheme to apply signals of pulsed eddy current testing (PECT) to reconstruct a deep stress corrosion crack (SCC) is proposed on the basis of a multi-layer and multi-frequency reconstruction strategy. First, a numerical method is introduced to extract conventional eddy current testing (ECT) signals of different frequencies from the PECT responses at different scanning points, which are necessary for multi-frequency ECT inversion. Second, the conventional fast forward solver for ECT signal simulation is upgraded to calculate the single-frequency pickup signal of a magnetic field by introducing a strategy that employs a tiny search coil. Using the multiple-frequency ECT signals and the upgraded fast signal simulator, we reconstructed the shape profiles and conductivity of an SCC at different depths layer-by-layer with a hybrid inversion scheme of the conjugate gradient and particle swarm optimisation. Several modelled SCCs of rectangular or stepwise shape in an SUS304 plate are reconstructed from simulated PECT signals with artificial noise. The reconstruction results show better precision in crack depth than the conventional ECT inversion method, which demonstrates the validity and efficiency of the proposed PECT inversion scheme.

  15. Microstructural and Stress Corrosion Cracking Characteristics of Austenitic Stainless Steels Containing Silicon

    Science.gov (United States)

    Andresen, Peter L.; Chou, Peter H.; Morra, Martin M.; Lawrence Nelson, J.; Rebak, Raul B.

    2009-12-01

    Austenitic stainless steels (SSs) core internal components in nuclear light water reactors (LWRs) are susceptible to irradiation-assisted stress corrosion cracking (IASCC). One of the effects of irradiation is the hardening of the SS and a change in the dislocation distribution in the alloy. Irradiation may also alter the local chemistry of the austenitic alloys; for example, silicon may segregate and chromium may deplete at the grain boundaries. The segregation or depletion phenomena at near-grain boundaries may enhance the susceptibility of these alloys to environmentally assisted cracking (EAC). The objective of the present work was to perform laboratory tests in order to better understand the role of Si in the microstructure, properties, electrochemical behavior, and susceptibility to EAC of austenitic SSs. Type 304 SS can dissolve up to 2 pct Si in the bulk while maintaining a single austenite microstructure. Stainless steels containing 12 pct Cr can dissolve up to 5 pct bulk Si while maintaining an austenite structure. The crack growth rate (CGR) results are not conclusive about the effect of the bulk concentration of Si on the EAC behavior of SSs.

  16. Status report: Intergranular stress corrosion cracking of BWR core shrouds and other internal components

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    On July 25, 1994, the US Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 94-03 to obtain information needed to assess compliance with regulatory requirements regarding the structural integrity of core shrouds in domestic boiling water reactors (BWRs). This report begins with a brief description of the safety significance of intergranular stress corrosion cracking (IGSCC) as it relates to the design and function of BWR core shrouds and other internal components. It then presents a brief history of shroud cracking events both in the US and abroad, followed by an indepth summary of the industry actions to address the issue of IGSCC in BWR core shrouds and other internal components. This report summarizes the staff`s basis for issuing GL 94-03, as well as the staff`s assessment of plant-specific responses to GL 94-03. The staff is continually evaluating the licensee inspection programs and the results from examinations of BWR core shrouds and other internal components. This report is representative of submittals to and evaluations by the staff as of September 30, 1995. An update of this report will be issued at a later date.

  17. Mechanism of intergranular stress corrosion cracking in HAZ for super-martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Yukio; Kimura, Mitsuo [Tubular Products and Casting Research Dept., JFE Steel Corporation, 1-1, Kawasaki-cho, Handa (Japan); Nakamichi, Haruo; Sato, Kaoru [Analysis and Characterization Research Dept., JFE Steel Corporation, 1-1, Minamiwatarida-cho, Kawasaki-ku, Kawasaki (Japan); Itakura, Noritsugu [Products Service and Development Dept., Chita Works, JFE Steel Corporation. 1-1, Kawasaki-cho, Handa (Japan); Masamura, Katsumi [Tubular Products Business Planning Dept., JFE Steel Corporation, 2-2-3, Uchisaiwai-sho, Chiyoda-ku, Tokyo (Japan)

    2004-07-01

    Mechanism of intergranular stress corrosion cracking (IGSCC) for heat affected zone (HAZ) of super-martensitic stainless steel was studied using two types of the steel. One was a lean grade, which was Mo free and low Ni, and the other was a high grade, which was Mo added and high Ni. Specimens received heat treatments simulating welding thermal cycles were applied to SCC tests. Cracks were observed in some specimens after U-bend SCC test under low pH environments. Thermal cycle conditions with sensitization were verified from the results. No crack was observed in the specimen with the thermal cycle simulating post welding heat treatment (PWHT) after sensitizing conditions. Therefore, PWHT was clarified to be effective to prevent the cracking. Cr carbides were observed along prior austenite grain boundary intermittently, and Cr depleted zone was confirmed on the grain boundary adjacent to carbides that precipitated on the grain boundary. It is, therefore, concluded that the cracking results from Cr depletion on prior austenite grain boundary accompanied by precipitation of Cr carbides under specific welding conditions. (authors)

  18. Assessment of NDE Technologies for Detection and Characterization of Stress Corrosion Cracking in LWRs

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Ryan M.; Ramuhalli, Pradeep; Toloczko, Mychailo B.; Bond, Leonard J.; Montgomery, Robert O.

    2012-12-31

    Stress corrosion cracking (SCC) in light water reactors (LWRs) has been a persistent form of degradation in the nuclear industry. Examples of SCC can be found for a range of materials in boiling and pressurized water reactor environments, including carbon steels, stainless steels, and nickel-base stainless alloys. The evolution of SCC is often characterized by a long initiation stage followed by a phase of more rapid crack growth to failure. This provides a relatively short window of opportunity to detect the start of observable SCC, and it is conceivable that SCC could progress from initiation to failure between subsequent examinations when managed by applying periodic in-service inspection techniques. Implementation of advanced aging management paradigms in the current fleet of LWRs will require adaptation of existing measurement technologies and development of new technologies to perform on-line measurements during reactor operation to ensure timely detection of material degradation and to support the implementation of advanced diagnostics and prognostics. This paper considers several non-destructive examination (NDE) technologies with known sensitivity to detection of indicators for SCC initiation and/or propagation, and assesses these technologies with respect to their ability to detect and accurately characterize the significance of an SCC flaw. Potential strategies to improve SCC inspection or monitoring performance are offered to benefit management of SCC degradation in LWRs.

  19. Utilizing various test methods to study the stress corrosion behavior of Al-Li-Cu alloys

    Science.gov (United States)

    Pizzo, P. P.; Galvin, R. P.; Nelson, H. G.

    1984-01-01

    Recently, much attention has been given to aluminum-lithium alloys because of rather substantial specific-strength and specific-stiffness advantages offered over commercial 2000and 7000-series aluminum alloys. An obstacle to Al-Li alloy development has been inherent limited ductility. In order to obtain a more refined microstructure, powder metallurgy (P/M) has been employed in alloy development programs. As stress corrosion (SC) of high-strength aluminum alloys has been a major problem in the aircraft industry, the possibility of an employment of Al-Li alloys has been considered, taking into account a use of Al-Li-Cu alloys. Attention is given to a research program concerned with the evaluation of the relative SC resistance of two P/M processed Al-Li-Cu alloys. The behavior of the alloys, with and without an addition of magnesium, was studied with the aid of three test methods. The susceptibility to SC was found to depend on the microstructure of the alloys.

  20. The stress-corrosion behavior of Al-Li-Cu alloys: A comparison of test methods

    Science.gov (United States)

    Rizzo, P. P.; Galvin, R. P.; Nelson, H. G.

    1982-01-01

    Two powder metallurgy processed (Al-Li-Cu) alloys with and without Mg addition were studied in aqueous 3.5% NaCl solution during the alternate immersion testing of tuning fork specimens, slow crack growth tests using fracture mechanics specimens, and the slow strain rate testing of straining electrode specimens. Scanning electron microscopy and optical metallography were used to demonstrate the character of the interaction between the Al-Li-Cu alloys and the selected environment. Both alloys are susceptible to SC in an aqueous 3.5% NaCl solution under the right electrochemical and microstructural conditions. Each test method yields important information on the character of the SC behavior. Under all conditions investigated, second phase particles strung out in rows along the extrusion direction in the alloys were rapidly attacked, and played principal role in the SC process. With time, larger pits developed from these rows of smaller pits and under certain electrochemical conditions surface cracks initiated from the larger pits and contributed directly to the fracture process. Evidence to support slow crack growth was observed in both the slow strain rate tests and the sustained immersion tests of precracked fracture mechanics specimens. The possible role of H2 in the stress corrosion cracking process is suggested.

  1. Development of Modified 304 Stainless Steel Resistant to Stress Corrosion Cracking in Chloride Environment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This was a feasibility study for a modified 304 steel resistant to stress corrosion cracking (SCC) in aqueous environment containing chloride. SCC tests were conducted potentiostaticaly with spot-welded specimens, which had both crevice and residual stress, mainly in 3 % NaCl solution at various temperatures to determine the critical temperature for SCC at and below which the steel would not suffer from SCC. The effects of individual alloying element of silicon, manganese and copper on SCC of 18Cr-14Ni steels which phosphor content is 0.002 % and molybdenum content is 0.01 % were examined. Addition of 1 or 2 % of copper has beneficial effect on resistance to SCC, while increasing silicon or manganese content has no significant effect. Critical temperature of the steel with 0.002 % of phosphor and 2 % of copper is 150 ℃, which is markedly higher than 50 ℃ of 304L steel. However, the beneficial effect of copper is reduced with increasing phosphor content. From practical viewpoint, the modified steel with good SCC resistance should have 0.01 %-0.015 % of phosphor and 0.3 % or more of molybdenum, because it is very difficult to reduce phosphor content below 0.008 % industrially and such molybdenum content is inevitably introduced through cost-saving melting process using return steel. Aluminium is to be added as another alloying element and 3 % of aluminium combined with 2 % of copper has been found to negate the deleterious effects of increased phosphor and molybdenum content. As a candidate steel at this stage, 14Cr-16Ni-0.013P-2Cu-1Al-(0.3-1)Mo steel has critical temperature of 110 ℃.

  2. H2S Stress Corrosion Tests of Welded Joint for X65 Pipeline Steel and Finite Element Numerical Analysis of Crack Tip

    Institute of Scientific and Technical Information of China (English)

    金晓军; 霍立兴; 张玉凤; 白秉仁; 李小巍; 曹军

    2003-01-01

    The microstructure of welded joint is surveyed and the mechanical properties of X65 pipeline steel are studied in this paper, which provides experimental basis of performance effect on stress corrosion. H2S stress corrosion cracking (SCC) tests on the steel are carried out in the environment based on NACE TM-01-77 solution. The threshold stress intensity factor and crack propagation velocity for base metal and HAZ are obtained. The susceptibility of welded joint for X65 pipeline steel to H2S stress corrosion cracking is investigated. The programming package ANSYS of finite element model (FEM) is used to perform the three-dimensional elastic-plastic finite element analysis of WOL specimens. Stress field and concentration of hydrogen distribution property of the crack tip are obtained.

  3. Lead-induced stress-corrosion cracking of alloy 600 in plausible steam generator crevice environments

    Energy Technology Data Exchange (ETDEWEB)

    Wright, M.D. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Manolescu, A. [Ontario Hydro Technologies, Toronto, Ontario (Canada); Mirzai, M. [Ontario Hydro, Toronto, Ontario (Canada)

    1999-03-01

    Laboratory stress-corrosion cracking (SCC) test environments were developed to simulate crevice chemistries representative of Bruce Nuclear Generating Station A (BNPD A) steam generators (SGs); these test environments were used to determine the susceptibility of Alloy 600 to lead-induced SCC under plausible SG conditions. Test environments were based on plant SG hideout return data and analysis of removed tubes and deposits. Deviations from the normal near-neutral crevice pH environment were considered to simulate possible faulted excursion crevice chemistry and to bound the postulated crevice pH range of 3 to 9 (at temperature). The effect of lead contamination up to 1000 ppm, but with an emphasis on the 100- to 500-ppm range, was determined. SCC susceptibility was investigated using constant extension rate tensile (CERT) tests and encapsulated C-ring tests. CERT tests were performed at 305 degrees C on tubing representative of BNPD A SG U-bends. The C-ring test method allowed a wider test matrix, covering 3 temperatures (280 degrees C, 304 degrees C and 315 degrees C), 3 strain levels (0.2%, 2% and 4%), and tubing representative of U-bends plus tubing given a simulated stress relief to represent material at the tube sheet. The results of this test program confirmed that in the absence of lead contamination, cracking does not occur in these concentrated, 3.3 to 8.9 pH range, crevice environments. Also, it appears that the concentrated crevice environments suppress lead-induced cracking relative to that seen in all-volatile-treatment (AVT) water. For the (static) C-ring tests, lead-induced SCC was only produced in the near-neutral crevice environment and was more severe at 500 ppm than at 100 ppm PbO. This trend was also observed in CERT tests, but some cracking-grain boundary attack occurred in acidic (pH 3.3) and alkaline (pH 8.9) environments. The C-ring tests indicated that a certain amount of resistance to cracking was imparted by simulated stress relief of

  4. Irradiation Programs and Test Plans to Assess High-Fluence Irradiation Assisted Stress Corrosion Cracking Susceptibility.

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    . Irradiation assisted stress corrosion cracking (IASCC) is a known issue in current reactors. In a 60 year lifetime, reactor core internals may experience fluence levels up to 15 dpa for boiling water reactors (BWR) and 100+ dpa for pressurized water reactors (PWR). To support a safe operation of our fleet of reactors and maintain their economic viability it is important to be able to predict any evolution of material behaviors as reactors age and therefore fluence accumulated by reactor core component increases. For PWR reactors, the difficulty to predict high fluence behavior comes from the fact that there is not a consensus of the mechanism of IASCC and that little data is available. It is however possible to use the current state of knowledge on the evolution of irradiated microstructure and on the processes that influences IASCC to emit hypotheses. This report identifies several potential changes in microstructure and proposes to identify their potential impact of IASCC. The susceptibility of a component to high fluence IASCC is considered to not only depends on the intrinsic IASCC susceptibility of the component due to radiation effects on the material but to also be related to the evolution of the loading history of the material and interaction with the environment as total fluence increases. Single variation type experiments are proposed to be performed with materials that are representative of PWR condition and with materials irradiated in other conditions. To address the lack of IASCC propagation and initiation data generated with material irradiated in PWR condition, it is proposed to investigate the effect of spectrum and flux rate on the evolution of microstructure. A long term irradiation, aimed to generate a well-controlled irradiation history on a set on selected materials is also proposed for consideration. For BWR, the study of available data permitted to identify an area of concern for long term performance of component. The efficiency of

  5. Stress corrosion study of PH13-8Mo stainless steel using the Slow Strain Rate Technique

    Science.gov (United States)

    Torres, Pablo D.

    1989-01-01

    The need for a fast and reliable method to study stress corrosion in metals has caused increased interest in the Slow Strain Rate Technique (SSRT) during the last few decades. PH13-8MoH950 and H1000 round tensile specimens were studied by this method. Percent reduction-in-area, time-to-failure, elongation at fracture, and fracture energy were used to express the loss in ductility, which has been used to indicate susceptibility to stress corrosion cracking (SCC). Results from a 3.5 percent salt solution (corrosive medium) were compared to those in air (inert medium). A tendency to early failure was found when testing in the vicinity of 1.0 x 10(-6) mm/mm/sec in the 3.5 percent salt solution. PH13-8Mo H1000 was found to be less likely to suffer SCC than PH13-8Mo H950. This program showed that the SSRT is promising for the SCC characterization of metals and results can be obtained in much shorter times (18 hr for PH steels) than those required using conventional techniques.

  6. Layer texture of hot-rolled BCC metals and its significance for stress-corrosion cracking of main gas pipelines

    Science.gov (United States)

    Perlovich, Yu. A.; Isaenkova, M. G.; Krymskaya, O. A.; Morozov, N. S.

    2016-10-01

    Based on data of X-ray texture analysis of hot-rolled BCC materials it was shown that the layerwise texture inhomogeneity of products is formed during their manufacturing. The effect can be explained by saturation with interstitial impurities of the surface layer, resulting in dynamical deformation aging (DDA). DDA prevents the dislocation slip under rolling and leads to an increase of lattice parameters in the external layer. The degree of arising inhomogeneity correlates with the tendency of hot-rolled sheets and obtained therefrom tubes to stress-corrosion cracking under exploitation, since internal layers have a compressive effect on external layers, and prevents opening of corrosion cracks at the tube surface.

  7. Stress Corrosion Cracking of the Drip Shield, The Waste Package Outer Barrier and the Stainless Steel Structural Material

    Energy Technology Data Exchange (ETDEWEB)

    C. Stephen

    2000-04-17

    One of the potential failure modes of the drip shield (DS), the waste package (WP) outer barrier, and the stainless structural material is the initiation and propagation of stress corrosion cracking (SCC) induced by the WP environment and various types of stresses that can develop in the DSs or the WPs. For the current design of the DS and WP, however, the DS will be excluded from the SCC evaluation because stresses that are relevant to SCC are insignificant in the DS. The major sources of stresses in the DS are loadings due to backfill and earthquakes. These stresses will not induce SCC because the stress caused by backfill is generally compressive stress and the stress caused by earthquakes is temporary in nature. The 316NG stainless steel inner barrier of the WP will also be excluded from the SCC evaluation because the SCC performance assessment will not take credit from the inner barrier. Therefore, the purpose of this document is to provide a detailed description of the process-level models that can be applied to assess the performance of the material (i.e., Alloy 22) used for the WP outer barrier subjected to the effects of SCC. As already mentioned in the development plan for the WP PMR (CRWMS M and O 1999e), this Analyses and Models Report (AMR) is to serve as a feed to the Waste Package Degradation (WPD) Total System Performance Assessment (TSPA) and Process Model Report (PMR).

  8. Quantitative characterization of initiation and propagation in stress corrosion cracking. An approach of a phenomenological model; Caracterisation quantitative de l`amorcage et de la propagation en corrosion sous contrainte. Approche d`une modelisation phenomenologique

    Energy Technology Data Exchange (ETDEWEB)

    Raquet, O.

    1994-11-25

    A purely phenomenological study of stress corrosion cracking was performed using the couple Z2CN 18.10 (304L) austenitic stainless steel/boiling MgCl{sub 2} aqueous solution. The exploitation of the morphological information (shape of the cracks and size distribution) available after constant elongation rate tests led to the proposal of an analytical expression of the crack initiation and growth rates. This representation allowed to quantitatively characterize the influence of the applied strain rate as well as the effect of corrosion inhibitors on the crack initiation and propagation phases. It can be used in the search for the stress corrosion cracking mechanisms as a `riddle` for the determination of the rate controlling steps. As a matter of fact, no mechanistic hypothesis has been used for its development. (author).

  9. Allowing for surface preparation in stress corrosion cracking modelling; Prise en compte de l`etat de surface dans la modelisation de la fissuration par corrosion sous contrainte

    Energy Technology Data Exchange (ETDEWEB)

    Berge, P.; Buisine, D. [Electricite de France (EDF), 92 - Clamart (France); Gelpi, A. [FRAMATOME, 92 - Paris-La-Defence (France)

    1997-12-31

    When a 600 alloy component is significantly deformed during installation, by welding, rolling, bending, its stress corrosion cracking in Pressurized Water Nuclear Reactor`s primary coolant, is significantly changed by the initial surface treatment. Therefore, the crack initiated time may be reduced by several orders of magnitude for certain surfaces preparations. Allowing for cold working of the surface, for which modelling is proposed, depends less on the degree of cold work then on the depths of the hardened layers. Honing hardens the metal over depths of about one micron for vessel head penetrations, for example, and has little influence on subsequent behaviour after the part deforms. On the other hand, coarser turning treatment produces cold worked layers which can reach several tens of microns and can very significantly reduce the initiation time compared to fine honing. So evaluation after depths of hardening is vital on test pieces for interpreting laboratory results as well as on service components for estimating their service life. Suppression by mechanical or chemical treatment of these layers, after deformation, seems to be the most appropriate solution for reducing over-stressing connected with surface treatment carried out before deformation. (author). 14 refs.

  10. The Efficacy of Mesenchymal Stem Cell Transplantation in Caustic Esophagus Injury: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Murat Kantarcioglu

    2014-01-01

    Full Text Available Introduction. Ingestion of corrosive substances may lead to stricture formation in esophagus as a late complication. Full thickness injury seems to exterminate tissue stem cells of esophagus. Mesenchymal stem cells (MSCs can differentiate into specific cell lineages and have the capacity of homing in sites of injury. Aim and Methods. We aimed to investigate the efficacy of MSC transplantation, on prevention of esophageal damage and stricture formation after caustic esophagus injury in rats. 54 rats were allocated into four groups; 4 rats were sacrificed for MSC production. Group 1, untreated controls (n: 10. Group 2, membrane labeled MSCs-treated rats (n: 20. Group 3, biodistribution of fluorodeoxyglucose labeled MSCs via positron emission tomography (PET imaging (n: 10. Group 4, sham operated (n: 10. Standard caustic esophageal burns were created and MSCs were transplanted 24 hours after. All rats were sacrificed at the 21st days. Results. PET scan images revealed the homing behavior of MSCs to the injury site. The histopathology damage score was not significantly different from controls. However, we demonstrated Dil labeled epithelial and muscle cells which were originating from transplanted MSCs. Conclusion. MSC transplantation after caustic esophageal injury may be a helpful treatment modality; however, probably repeated infusions are needed.

  11. Corrosion Failures in Marine Environment

    Directory of Open Access Journals (Sweden)

    R. Krishnan

    1985-04-01

    Full Text Available This paper gives a brief description of typical marine environments and the most common form of corrosion of materials used in this environment. Some typical case histories of failures pertaining to pitting, bimetallic corrosion, dealloying, cavitation and stress corrosion cracking are illustrated as typical examples of corrosion failures.

  12. Pacific Northwest National Laboratory Investigation of the Stress Corrosion Cracking in Nickel-Base Alloys, Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, Stephen M.; Toloczko, Mychailo B.; Olszta, Matthew J.

    2012-03-01

    The objective of this program is to evaluate the primary water stress corrosion cracking (PWSCC) susceptibility of high chromium alloy 690 and its weld metals, establish quantitative measurements of crack-growth rates and determine relationships among cracking susceptibility, environmental conditions and metallurgical characteristics. Stress-corrosion, crack-growth rates have been determined for 12 alloy 690 specimens, 11 alloy 152/52/52M weld metal specimens, 4 alloy 52M/182 overlay specimens and 2 alloy 52M/82 inlay specimens in simulated PWR primary water environments. The alloy 690 test materials included three different heats of extruded control-rod-drive mechanism (CRDM) tubing with variations in the initial material condition and degree of cold work for one heat. Two cold-rolled (CR) alloy 690 plate heats were also obtained and evaluated enabling comparisons to the CR CRDM materials. Weld metal, overlay and inlay specimens were machined from industry mock ups to provide plant-representative materials for testing. Specimens have been tested for one alloy 152 weld, two alloy 52 welds and three alloy 52M welds. The overlay and inlay specimens were prepared to propagate stress-corrosion cracks from the alloy 182 or 82 material into the more resistant alloy 52M. In all cases, crack extension was monitored in situ by direct current potential drop (DCPD) with length resolution of about +1 µm making it possible to measure extremely low growth rates approaching 5x10-10 mm/s. Most SCC tests were performed at 325-360°C with hydrogen concentrations from 11-29 cc/kg; however, environmental conditions were modified during a few experiments to evaluate the influence of temperature, water chemistry or electrochemical potential on propagation rates. In addition, low-temperature (~50°C) cracking behavior was examined for selected alloy 690 and weld metal specimens. Extensive characterizations have been performed on material microstructures and stress-corrosion cracks by

  13. Critical assessment of precracked specimen configuration and experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate

    Science.gov (United States)

    Domack, M. S.

    1985-01-01

    A research program was conducted to critically assess the effects of precracked specimen configuration, stress intensity solutions, compliance relationships and other experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate. Modified compact and double beam wedge-loaded specimens were tested and analyzed to determine the threshold stress intensity factor and stress corrosion crack growth rate. Stress intensity solutions and experimentally determined compliance relationships were developed and compared with other solutions available in the literature. Crack growth data suggests that more effective crack length measurement techniques are necessary to better characterize stress corrosion crack growth. Final load determined by specimen reloading and by compliance did not correlate well, and was considered a major source of interlaboratory variability. Test duration must be determined systematically, accounting for crack length measurement resolution, time for crack arrest, and experimental interferences. This work was conducted as part of a round robin program sponsored by ASTM committees G1.06 and E24.04 to develop a standard test method for stress corrosion testing using precracked specimens.

  14. Interaction of aqueous caustic with acidic oils

    Energy Technology Data Exchange (ETDEWEB)

    Chiwetelu, C.I.; Hornof, V.; Neale, G.H. (Univ. of Ottawa, Ottawa, ON (Canada))

    High content of native carboxylic acids make heavy oils acidic. It is generally accepted that these acids react with caustic reagents present in floodwater, resulting in the in-situ formation of surface active soap anions. When these adsorb at the oil-water interface, they can drastically lower the interfacial tension to the point where residual oil is mobilized. The most intriguing aspect of these acid/caustic interactions is the dynamic nature of the interfacial tension. Given a sufficiently long time, the dynamic tension would attain an equilibrium state. Measurements were made of the equilibrium interfacial tensions of acidified oleic phases contacted with a wide range of caustic concentrations in the aqueous phase. A novel measurement technique (photomicropendography) was used, and data analysis was carried out by nonlinear regression. The present approach utilizes pre-selected fatty acids in a defined oleic phase, enabling quantification of relevant model parameters and facilitating evaluation of key variables influencing interfacial activity. The acid ionization constant and the equilibrium constant governing the formation of inactive soap species were found to be the most important parameters for systems of oleic and lauric acids dissolved in hexadecane. Regression analysis showed that the acid dissociation constant (pKa) of oleic acid ranged from 6.2 to 6.9 and was dependent on the working acid concentration. For lauric acid, the pKa values were in the range of 9 to 11 depending on the caustic concentration of the aqueous phase. Species aggregation in both the oleic and aqueous phases is mostly responsible for the variations in pKa values. 30 refs., 10 figs., 4 tabs.

  15. Potential mechanisms for corrosion and stress corrosion cracking failure of 3013 storage containers composed of 316 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kolman, D.G.; Butt, D.P.

    1998-03-01

    The degradation of 316 stainless steel (SS) storage container materials is a potential problem for radioactive waste disposition. Container materials will be exposed to significant ionizing radiation, elevated temperatures, embrittling and/or alloying agents (e.g., gallium), chloride-containing compounds (as much as 20 wt% Cl or Cl{sup {minus}}), oxidizing compounds, and a limited quantity of moisture. Additionally, containers will contain welds that have heterogeneous composition due to solute segregation and that may retain significant residual stress. All of the above-listed environmental and material conditions have been shown to be deleterious to material integrity under certain conditions. Unfortunately, the precise conditions within each container and environment is unknown and may vary widely from container to container. Thus, no single test or set of tests will be able mimic the broad range of storage container conditions. Additionally, material behavior cannot be predicted because the synergistic effects of temperature, time, chloride, moisture, sensitization, weldments, salt formation, etc., have not been fully studied. The complexity and uncertainty of storage conditions precludes any detailed recommendations. This document attempts to detail selected previous studies and to suggest some general guidelines for storage of radioactive waste. Because of the voluminous research in this area, this review cannot be considered to be comprehensive. Readers are directed to references that contain detailed reviews of particular processes for more information. Note that the effect of gallium on the degradation of SS storage containers has been discussed elsewhere and will not be discussed here.

  16. Cracks propagation by stress corrosion cracking in conditions of Boiling Water Reactor (BWR); Propagacion de grietas por corrosion bajo esfuerzo en condiciones de reactor de agua hirviente (BWR)

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes C, P

    2003-07-01

    This work presents the results of the assays carried out in the Laboratory of Hot Cells of the National Institute of Nuclear Research (ININ) to a type test tube Compact Tension (CT), built in steel austenitic stainless type 304L, simulating those conditions those that it operates a Boiling Water Reactor (BWR), at temperature 288 C and pressure of 8 MPa, to determine the speed to which the cracks spread in this material that is of the one that different components of a reactor are made, among those that it highlights the reactor core vessel. The application of the Hydrogen Chemistry of the Water is presented (HWC) that is one alternative to diminish the corrosion effect low stress in the component, this is gets controlling the quantity of oxygen and of hydrogen as well as the conductivity of the water. The rehearsal is made following the principles of the Mechanics of Elastic Lineal Fracture (LEFM) that considers a crack of defined size with little plastic deformation in the tip of this; the measurement of crack advance is continued with the technique of potential drop of direct current of alternating signal, this is contained inside the standard Astm E-647 (Method of Test Standard for the Measurement of Speed of Growth of Crack by fatigue) that is the one that indicates us as carrying out this test. The specifications that should complete the test tubes that are rehearsed as for their dimensions, it forms, finish and determination of mechanical properties (tenacity to the fracture mainly) they are contained inside the norm Astm E-399, the one which it is also based on the principles of the fracture mechanics. The obtained results were part of a database to be compared with those of other rehearsals under different conditions, Normal Chemistry of the Water (NWC) and it dilutes with high content of O{sub 2}; to determine the conditions that slow more the phenomena of stress corrosion cracking, as well as the effectiveness of the used chemistry and of the method of

  17. In Situ Causticizing for Black Liquor Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Scott Alan Sinquefield

    2005-10-01

    Black liquor gasification offers a number of attractive incentives to replace Tomlinson boilers but it also leads to an increase in the causticizing load. Reasons for this have been described in previous reports (FY04 ERC, et.al.). The chemistries have also been covered but will be reviewed here briefly. Experimental results of the causticizing reactions with black liquor are presented here. Results of the modeling work were presented in detail in the Phase 1 report. They are included in Table 2 for comparison but will not be discussed in detail. The causticizing agents were added to black liquor in the ratios shown in Table 1, mixed, and then spray-dried. The mixture ratios (doping levels) reflect amount calculated from the stoichiometry above to achieve specified conversions shown in the table. The solids were sieved to 63-90 microns for use in the entrained flow reactors. The firing conditions are shown in Table 2. Pictures and descriptions of the reactors can be found in the Phase 1 annual report. Following gasification, the solids (char) was collected and analyzed by coulometric titration (for carbonate and total carbon), and by inductively coupled plasma emission spectroscopy (ICP) for a wide array of metals.

  18. Influence of nitrogen on the stress corrosion cracking resistance of austenitic stainless steels in chloride environment; Influence de l'azote sur la resistance a la corrosion sous contrainte d'aciers inoxydables austenitiques en milieu chlorure

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, S

    2001-11-01

    The aim of this study is to investigate the influence of nitrogen additions on the Stress Corrosion Cracking (SSC) resistance of austenitic stainless steel in chloride environment. The investigation was carried out in two part: first, an experimental investigation with model industrial steels was carried out and secondly, numerical simulations based on the Corrosion Enhanced Plasticity Model were developed. Both slow strain rate tensile tests and constant load test of the different steels in boiling MgCl{sub 2} (153 deg C) at free potential show that, for a given plastic strain rate, nitrogen addition increases the critical stress for crack initiation without influencing the crack propagation rate. We observed that the creep rate under constant load was affected by the nitrogen content. As a consequence, the SCC behaviour (cracks density and propagation rate) depends on the nitrogen content. We thus confirm that the nitrogen content influences the corrosion - deformation interaction mechanisms via its positive contribution to the flow stress. These experimental results are reproduced semi-quantitatively by means of numerical simulations at the scale of crack. - dislocation interactions. The presence of nitrogen is modelled by an increased lattice friction stress, which in turn affects the dynamics of crack tip shielding by dislocation pile-ups. We conclude that nitrogen addition in austenitic stainless steels increases the SC crack initiation stress in proportion of the increased flow stress, without penalty in terms of SC crack propagation rate. (author)

  19. Study of alloy 600`S stress corrosion cracking mechanisms in high temperature water; Etude des mecanismes de corrosion sous contrainte de l`alliage 600 dans l`eau a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rios, R.

    1994-06-01

    In order to better understand the mechanisms involved in Alloy 600`s stress corrosion cracking in PWR environment, laboratory tests were performed. The influence of parameters pertinent to the mechanisms was studies : hydrogen and oxygen overpressures, local chemical composition, microstructure. The results show that neither hydrogen nor dissolution/oxidation, despite their respective roles in the process, are sufficient to account for experimental facts. SEM observation of micro-cleavage facets on specimens` fracture surfaces leads to pay attention to a new mechanism of corrosion/plasticity interactions. (author). 113 refs., 73 figs., 15 tabs., 4 annexes.

  20. Preparation Femtosecond Laser Prevention for the Cold-Worked Stress Corrosion Crackings on Reactor Grade Low Carbon Stainless Steel

    CERN Document Server

    John Minehara, Eisuke

    2004-01-01

    We report here that the femtosecond lasers like low average power Ti:Sapphire lasers, the JAERI high average power free-electron laser and others could peel off and remove two stress corrosion cracking (SCC) origins of the cold-worked and the cracking susceptible material, and residual tensile stress in hardened and stretched surface of low-carbon stainless steel cubic samples for nuclear reactor internals as a proof of principle experiment except for the third origin of corrosive environment. Because a 143 °C and 43% MgCl2 hot solution SCC test was performed for the samples to simulate the cold-worked SCC phenomena of the internals to show no crack at the laser-peered off strip on the cold-worked side and ten-thousands of cracks at the non-peeled off on the same side, it has been successfully demonstrated that the femtosecond lasers could clearly remove the two SCC origins and could resultantly prevent the cold-worked SCC.

  1. Sulfide stress corrosion study of a super martensitic stainless steel in H2S sour environments: Metallic sulfides formation and hydrogen embrittlement

    Science.gov (United States)

    Monnot, Martin; Nogueira, Ricardo P.; Roche, Virginie; Berthomé, Grégory; Chauveau, Eric; Estevez, Rafael; Mantel, Marc

    2017-02-01

    Thanks to their high corrosion resistance, super martensitic stainless steels are commonly used in the oil and gas industry, particularly in sour environments. Some grades are however susceptible to undergo hydrogen and mechanically-assisted corrosion processes in the presence of H2S, depending on the pH. The martensitic stainless steel EN 1.4418 grade exhibits a clear protective passive behavior with no sulfide stress corrosion cracking when exposed to sour environments of pH ≥ 4, but undergoes a steep decrease in its corrosion resistance at lower pH conditions. The present paper investigated this abrupt loss of corrosion resistance with electrochemical measurements as well as different physicochemical characterization techniques. Results indicated that below pH 4.0 the metal surface is covered by a thick (ca 40 μm) porous and defect-full sulfide-rich corrosion products layer shown to be straightforwardly related to the onset of hydrogen and sulfide mechanically-assisted corrosion phenomena.

  2. Scanning reference electrode techniques in localized corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, H.S.; Vyas, B.

    1979-04-01

    The principles, advantages, and implementations of scanning reference electrode techniques are reviewed. Data related to pitting, intergranular corrosion, welds and stress corrosion cracking are presented. The technique locates the position of localized corrosion and can be used to monitor the development of corrosion and changes in the corrosion rate under a wide range of conditions.

  3. Effect of heat input on the microstructure, residual stresses and corrosion resistance of 304L austenitic stainless steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Unnikrishnan, Rahul, E-mail: rahulunnikrishnannair@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Idury, K.S.N. Satish, E-mail: satishidury@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Ismail, T.P., E-mail: tpisma@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Bhadauria, Alok, E-mail: alokbhadauria1@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Shekhawat, S.K., E-mail: satishshekhawat@gmail.com [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay (IITB), Powai, Mumbai 400076, Maharashtra (India); Khatirkar, Rajesh K., E-mail: rajesh.khatirkar@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Sapate, Sanjay G., E-mail: sgsapate@yahoo.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India)

    2014-07-01

    Austenitic stainless steels are widely used in high performance pressure vessels, nuclear, chemical, process and medical industry due to their very good corrosion resistance and superior mechanical properties. However, austenitic stainless steels are prone to sensitization when subjected to higher temperatures (673 K to 1173 K) during the manufacturing process (e.g. welding) and/or certain applications (e.g. pressure vessels). During sensitization, chromium in the matrix precipitates out as carbides and intermetallic compounds (sigma, chi and Laves phases) decreasing the corrosion resistance and mechanical properties. In the present investigation, 304L austenitic stainless steel was subjected to different heat inputs by shielded metal arc welding process using a standard 308L electrode. The microstructural developments were characterized by using optical microscopy and electron backscattered diffraction, while the residual stresses were measured by X-ray diffraction using the sin{sup 2}ψ method. It was observed that even at the highest heat input, shielded metal arc welding process does not result in significant precipitation of carbides or intermetallic phases. The ferrite content and grain size increased with increase in heat input. The grain size variation in the fusion zone/heat affected zone was not effectively captured by optical microscopy. This study shows that electron backscattered diffraction is necessary to bring out changes in the grain size quantitatively in the fusion zone/heat affected zone as it can consider twin boundaries as a part of grain in the calculation of grain size. The residual stresses were compressive in nature for the lowest heat input, while they were tensile at the highest heat input near the weld bead. The significant feature of the welded region and the base metal was the presence of a very strong texture. The texture in the heat affected zone was almost random. - Highlights: • Effect of heat input on microstructure, residual

  4. The Role of Stress in the Corrosion Cracking of Aluminum Alloys

    Science.gov (United States)

    2013-03-01

    orthogonal to the other two directions. This system is used for sheet, extrusions , and forgings with nonsymmetrical grain flow [18]. All testing...around the constituent particles and then spreads to the grain boundaries. It is not possible to determine from the present results if the IGC...International, 2011, pp.1-8. [30] J. R. Scully et al., " Spreading of intergranular corrosion on the surface of sensitized Al-4.4Mg alloys: A general finding

  5. Intergranular stress corrosion cracking of type 304 stainless steels treated with inhibitive chemicals in high temperature pure water

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, T.K. [Nuclear Science and Technology Development Center, National Tsing-Hua Univ. Taiwan (China); Lee, M.Y.; Tsai, C.H. [Department of Engineering and System Science, National Tsing-Hua Univ. Taiwan (China)

    2002-07-01

    Electrochemical potentiodynamic polarizations, electrochemical corrosion potential (ECP) measurements and slow strain rate tensile (SSRT) tests were conducted to investigate the intergranular stress corrosion cracking (IGSCC) characteristics of Type 304 stainless steels treated with inhibitive chemicals in simulated boiling water reactor (BWR) environments. A number of thermally sensitized specimens were prepared and were pre-oxidized in a 288 C environment with the presence of 300 ppb dissolved oxygen for 360 hours. Most of the specimens were then treated with various chemicals including powdered zirconium oxide (ZrO{sub 2}), powdered titanium oxide (TiO{sub 2}), and zirconyl nitrate [ZrO(NO{sub 3}){sub 2}] via static immersion at 90 C, 150 C, and 200 C. Test environments were specifically designed in a circulation loop to create a dissolved oxygen concentration of 300 ppb. Test results showed that the corrosion current densities of all treated specimens were lower than that of the untreated, pre-oxidized specimen at ambient temperature in a solution mixed with 1 mM K{sub 3}Fe(CN){sub 6} and 1 mM K{sub 4}Fe(CN){sub 6}. The ECPs of the treated specimens could be lower or higher than that of the pre-oxidized one at 288 C, depending upon the type of treating chemical and the treating temperature. In addition, IGSCC was observed on all specimens (treated or untreated) in the same environment. However, the untreated specimen exhibited lower elongation, shorter failure time, and more secondary cracks on the side surfaces. It was therefore suggested that inhibitive chemicals such as ZrO{sub 2}, TiO{sub 2}, and ZrO(NO{sub 3}){sub 2} did provide a certain degree of enhancement in improving the mechanical behavior of the treated specimens and in prolonging the IGSCC initiation time. (authors)

  6. Stress corrosion cracking of welded joints of super-martensitic stainless steel in H{sub 2}S free environment

    Energy Technology Data Exchange (ETDEWEB)

    Hoerner, Bertrand; Bayle, Bernard; Delafosse, David [Centre Science des Materiaux et des Structures - URA CNRS 5146, ENS Mines de Saint-Etienne, 158 Cours Fauriel, 42023 Saint-Etienne cedex 02 (France); Ligier, Vincent [CRMC, INDUSTEEL Creusot, 56, rue Clemenceau, BP 56 - 71 202 Le Creusot Cedex (France)

    2004-07-01

    Due to their combination of good weldability and good mechanical properties, low carbon super-martensitic stainless steels are good candidates for oil and gas flow line applications. These alloys have already been used in slightly sour environments containing chlorides, CO{sub 2} and H{sub 2}S. The properties of a welded joint whose composition is matching or superduplex that of the base metal are investigated. The base material is the super-martensitic stainless steels medium alloy: 13Cr-4.5Ni-1.5Mo. The Heat Affected Zone (HAZ) of girth welds may be sensitive to stress corrosion cracking and presents distinct features intergranular cracking when tested in four-point bending in a sour deaerated environment at temperatures around 100 deg. C. The electrochemical properties of the medium alloy and the matching welded joint + HAZ were determined in a chloride-containing environment without H{sub 2}S. A passive film is formed on polished samples. This film is less protective for the welded joint + HAZ samples than in the base metal. Moreover, the pitting corrosion resistance is strongly decreased in the HAZ. Slow strain rate tensile tests were conducted in a de-aerated solution without H{sub 2}S. They reproduce the same type of cracking as was observed in four point bending tests in a sour environment: initiation in the HAZ and an intergranular crack with a very brittle aspect and no significant trace of corrosion. The presence H{sub 2}S is not the prevailing factor for the occurrence of cracking. Furthermore, it is not necessary to have a specific surface condition for crack initiation to occur in slow strain rate tension, as it is the case four point bend tests where initiation appears to be controlled by the surface condition (chemical and / or geometrical). Finally, a simulated PWHT strongly increase the resistance to SSC. (authors)

  7. Hydrogen embrittlement and hydrogen induced stress corrosion cracking of high alloyed austenitic materials; Wasserstoffversproedung und wasserstoffinduzierte Spannungsrisskorrosion hochlegierter austenitischer Werkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Mummert, K.; Uhlemann, M.; Engelmann, H.J. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany)

    1998-11-01

    The susceptiblity of high alloyed austenitic steels and nickel base alloys to hydrogen-induced cracking is particularly determined by 1. the distribution of hydrogen in the material, and 2. the microstructural deformation behaviour, which last process is determined by the effects of hydrogen with respect to the formation of dislocations and the stacking fault energy. The hydrogen has an influence on the process of slip localization in slip bands, which in turn affects the microstructural deformation behaviour. Slip localization increases with growing Ni contents of the alloys and clearly reduces the ductility of the Ni-base alloy. Although there is a local hydrogen source involved in stress corrosion cracking, emanating from the corrosion process at the cathode, crack growth is observed only in those cases when the hydrogen concentration in a small zone ahead of the crack tip reaches a critical value with respect to the stress conditions. Probability of onset of this process gets lower with growing Ni content of the alloy, due to increasing diffusion velocity of the hydrogen in the austenitic lattice. This is why particularly austenitic steels with low Ni contents are susceptible to transcrystalline stress corrosion cracking. In this case, the microstructural deformation process at the crack tip is also influenced by analogous processes, as could be observed in hydrogen-loaded specimens. (orig./CB) [Deutsch] Die Empfindlichkeit von hochlegierten austentischen Staehlen und Nickelbasislegierungen gegen wasserstoffinduziertes Risswachstum wird im wesentlichen bestimmt durch 1. die Verteilung von Wasserstoff im Werkstoff und 2. das mikrostrukturelle Verformungsverhalten. Das mikrostrukturelle Deformationsverhalten ist wiederum durch den Einfluss von Wasserstoff auf die Versetzungsbildung und die Stapelfehlerenergie charakterisiert. Das mikrostrukturelle Verformungsverhalten wird durch wasserstoffbeeinflusste Gleitlokalisierung in Gleitbaendern bestimmt. Diese nimmt mit

  8. Effect of pH Value on Stress Corrosion Cracking of X70 Pipeline Steel in Acidic Soil Environment

    Institute of Scientific and Technical Information of China (English)

    Zhiyong LIU; Cuiwei DU; Xin ZHANG; Fuming WANG; Xiaogang LI

    2013-01-01

    The effect of pH value on the stress corrosion cracking (SCC) of API X70 pipeline steel in simulated acidic soil solutions was investigated by using slow strain rate test,electrochemical polarization curves,electrochemical impedance spectroscopy,and scanning electron microscopy.pH plays an important role in the susceptibility and electrochemical mechanism of SCC.The pH higher than 5 has no significant effect on electrochemical processes.By contrast,the pH lower than 5 intensifies cathodic hydrogen evolution reactions,thus increasing the cathodic current and corrosion potential.Under different pH values,the SCC mechanism of X70 pipeline steel varies among anodic dissolution (AD),hydrogen embrittlement (HE),and the combination of AD and HE (AD + HE) with variations of applied potential.At-850 mVSCE,the SCC mechanism is HE if pH is less than 4 or AD + HE if pH value is more positive.

  9. Atmospheric-Induced Stress Corrosion Cracking of Grade 2205 Duplex Stainless Steel—Effects of 475 °C Embrittlement and Process Orientation

    Directory of Open Access Journals (Sweden)

    Cem Örnek

    2016-07-01

    Full Text Available The effect of 475 °C embrittlement and microstructure process orientation on atmospheric-induced stress corrosion cracking (AISCC of grade 2205 duplex stainless steel has been investigated. AISCC tests were carried out under salt-laden, chloride-containing deposits, on U-bend samples manufactured in rolling (RD and transverse directions (TD. The occurrence of selective corrosion and stress corrosion cracking was observed, with samples in TD displaying higher propensity towards AISCC. Strains and tensile stresses were observed in both ferrite and austenite, with similar magnitudes in TD, whereas, larger strains and stresses in austenite in RD. The occurrence of 475 °C embrittlement was related to microstructural changes in the ferrite. Exposure to 475 °C heat treatment for 5 to 10 h resulted in better AISCC resistance, with spinodal decomposition believed to enhance the corrosion properties of the ferrite. The austenite was more susceptible to ageing treatments up to 50 h, with the ferrite becoming more susceptible with ageing in excess of 50 h. Increased susceptibility of the ferrite may be related to the formation of additional precipitates, such as R-phase. The implications of heat treatment at 475 °C and the effect of process orientation are discussed in light of microstructure development and propensity to AISCC.

  10. Effect of high energy shot peening pressure on the stress corrosion cracking of the weld joint of 304 austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhiming, Lu, E-mail: lzm@zjut.edu.cn; Laimin, Shi, E-mail: 810050107@qq.com; Shenjin, Zhu, E-mail: 523469865@qq.com; Zhidong, Tang, E-mail: 466054569@qq.com; Yazhou, Jiang, E-mail: 191268219@qq.com

    2015-06-18

    The weld joint of 304 stainless steel is treated using high energy shot peening(HESP) with various shot peening pressures. The grain size and metallographic microstructure of the specimen surface layer are analyzed using the X-ray diffraction method, and the surface hardness is measured. Slow strain rate tension tests are then performed to investigate the effect of shot peening pressure on the stress corrosion sensitivity. The results show that in the surface layer of the specimen, the grain refinement, hardness and the strain-induced plastic deformation all increase with the increasing shot peening pressure. Martensitic transformation is observed in the surface layer after being treated with HESP. The martensite phase ratio is found to increase with increasing shot peening pressure. The result also shows that the effects of the shot peening treatment on the stress corrosion sensitivity index depend on the shot peening pressure. When the shot peening pressure is less than 0.4 MPa, the grain refinement effect plays the main role, and the stress corrosion sensitivity index decreases with the increasing shot peening pressure. In contrast, when the shot peening pressure is higher than 0.4 MPa, the martensite transformation effect plays the main role, the stress corrosion sensitivity index increases with increasing shot peening pressure.

  11. Corrosion and Corrosion Control in Light Water Reactors

    Science.gov (United States)

    Gordon, Barry M.

    2013-08-01

    Serious corrosion problems have plagued the light water reactor (LWR) industry for decades. The complex corrosion mechanisms involved and the development of practical engineering solutions for their mitigation will be discussed in this article. After a brief overview of the basic designs of the boiling water reactor (BWR) and pressurized water reactor (PWR), emphasis will be placed on the general corrosion of LWR containments, flow-accelerated corrosion of carbon steel components, intergranular stress corrosion cracking (IGSCC) in BWRs, primary water stress corrosion cracking (PWSCC) in PWRs, and irradiation-assisted stress corrosion cracking (IASCC) in both systems. Finally, the corrosion future of both plants will be discussed as plants extend their period of operation for an additional 20 to 40 years.

  12. Embrittlement and anodic process in stress corrosion cracking: study of the influent micro-mechanical parameters; Fragilisation et processus anodiques en corrosion sous contrainte: etude des parametres micro-mecaniques influents

    Energy Technology Data Exchange (ETDEWEB)

    Tinnes, J.Ph

    2006-11-15

    We study the influence of local mechanical parameters on crack propagation in Stress Corrosion Cracking, at the scale of the microstructure. Two systems are compared: the CuAl{sub 9}Ni{sub 3}Fe{sub 2} copper-aluminium alloy in synthetic sea water under cathodic polarization, where the crack propagation mechanism is related to strain-assisted anodic dissolution, and the 316L austenitic stainless steel in MgCl{sub 2} solution, where embrittlement mechanisms related to hydrogen effects prevail. We use micro-notched tensile specimen that allow to study isolated short cracks. These experiments are modelled by means of finite elements calculations, and further characterized by Electron Back scattered Diffraction (EBSD) in the case of the 316L alloy. In terms of the local mechanical parameters that control propagation, fundamental differences are outlined between the two systems. They are discussed from the viewpoint of the available models of Stress Corrosion Cracking. (author)

  13. Effect of a novel three-step aging on strength, stress corrosion cracking and microstructure of AA7085

    Institute of Scientific and Technical Information of China (English)

    陈送义; 陈康华; 董朋轩; 叶升平; 黄兰萍; 阳代军

    2016-01-01

    The influence of a novel three-step aging on strength, stress corrosion cracking (SCC) and microstructure of AA7085 was investigated by tensile testing and slow strain rate testing combined with transmission electron microscopy (TEM). The results indicate that with the increase of second-step aging time of two-step aging, the mechanical properties increase first and then decrease, while the SCC resistance increases. Compared with two-step aging, three-step aging treatment improves SCC resistance and the strength increases by about 5%. The effects of novel three-step aging on strength and SCC resistance are explained by the role of matrix precipitates and grain boundary precipitates, respectively.

  14. Finite element model for expansive stress due to corrosion of reinforced concrete structures; Analisis con elemento finito de los esfuerzos expansivos por corrosion en las estructuras de concreto reforzado

    Energy Technology Data Exchange (ETDEWEB)

    Castorena Gonzalez, J.H.; Calderon Guillen, J.A. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: kstor28@yahoo.com.mx; cajoel_99@yahoo.com; Almeraya Calderon, F.; Gaona Tiburcio, C. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: facundo.almeraya@cimav.edu.mx; citlalli.gaona@cimav.edu.mx; Almaral Sanchez, J.L. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: jalmaral@gmail.com; Martinez Villafane, A. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: martinez.villafane@cimav.edu.mx

    2011-01-15

    The corrosion in the reinforcement steel is a problem that diminishes the useful life of reinforced concrete structures, reside committing its structural security. In the available models to estimate the mechanical effect of the corrosion, it is assumed that the corroded steel, through the oxides that grow to its surroundings, exercises a pressure on the surrounding concrete supposing a problem of plane stress or plane strain. In this work, the problem is modeled with three-dimensional finite element starting from an experiment on a subjected cylinder to accelerated corrosion, with strain gage to measure the pressure indirectly in the interface steel-concrete. From the results obtained it can be concluded that the effect of the length of corroded steel, anodic length, has a significant effect on the magnitude of the pressure in the interface steel-concrete, fact that can be used to improve the existing models. [Spanish] La corrosion en el acero de refuerzo es un problema que disminuye la vida util en las estructuras de concreto reforzado, ademas de comprometer su seguridad estructural. En los modelos disponibles para estimar el efecto mecanico de la corrosion, se supone que el acero corroido, a traves de los oxidos que crecen a su alrededor, ejercen una presion sobre el concreto circundante suponiendo un problema de esfuerzos o deformaciones planas, En el presente trabajo, se modela el problema con elemento finito tridimensional a partir de un experimento sobre un cilindro de concreto reforzado sometido a corrosion acelerada, instrumentado para medir indirectamente la presion en la interfase acero-concreto. De los resultados obtenidos se concluye que el efecto de la longitud de acero corroido, longitud anodica, tiene un efecto significativo sobre la magnitud de la presion en la interfase acero-concreto, hecho que puede ser utilizado para mejorar los modelos existentes.

  15. Time exposure studies on stress corrosion cracking of aluminum 2014-T6, 2219-T87, 2014-T651, 7075-T651, and titanium 6Al-4V

    Science.gov (United States)

    Terrell, J.

    1973-01-01

    The effect of a constant applied stress in crack initiation of aluminum 2014-T6, 2219-T87, 2014-T651, 7075-T651 and titanium 6Al-4V has been investigated. Aluminum c-ring specimens (1-inch diameter) and u-band titanium samples were exposed continuously to a 3.5% NaCl solution (pH 7) and organic fluids of ethyl, methyl, and iso-propyl alcohol (reagent purity), and demineralized distilled water. Corrosive action was observed to begin during the first and second day of constant exposure as evidenced by accumulation of hydrogen bubbles on the surface of stressed aluminum samples. However, titanium stressed specimens showed no reactions to its environment. Results of this investigation seems to suggest that aluminum 2014-T6, aluminum 7075-T651 and aluminum 2014-T651 are susceptible to stress corrosion cracking in chloride solution (NaCl), while aluminum 2219-T87 seem to resist stress corrosion cracking in sodium chloride at three levels of stress (25%, 50%, and 75% Y.S.). In organic fluids of methyl, ethyl, and iso-propyl alcohol, 2014-T6 and 7075-T651 did not fail by SCC; but 2014-T651 was susceptible to SCC in methly alcohol, but resistant in ethyl alcohol, iso-propyl alcohol and demineralized distilled water.

  16. The influence of modified water chemistries on metal oxide films, activity build-up and stress corrosion cracking of structural materials in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Maekelae, K.; Laitinen, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for {sup 60}Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (orig.) 127 refs.

  17. Caustics and Caustic-Diffraction in Laser Shadowgraphy of a Sessile Drop and Identification of Profile Near Contact Line

    Science.gov (United States)

    Zhang, Neng-Li; Chao, David F.

    2003-01-01

    This paper presents an optical method based on the caustics and caustic-difraction in laser shadowgaphy of a sessile drop to identify and estimate the drop profile near the contact line. A parallel laser beam passes through a liquid sessile drop placed on a transparent substrate to produce a shadowgraphic image of the drop on the screen far from the substrate. Along the inflection line of the drop the Gaussian curvature of the wavefront deformed by the drop vanishes, and therefore the inflection line gives caustics in the far field of the wave, which can be seen on the screen. The neighboring light rays at both sides of the inflection line interfere with each other to form interference fringes at the inner side of the caustics. According to the pattern of the caustics, the drop-profile shape can be identified and estimated.

  18. CF-62钢制球罐防范硫化氢应力腐蚀措施%Countermeasures of H2S Stress Corrosion in CF-62 Steel Spherical Tank

    Institute of Scientific and Technical Information of China (English)

    刘巍

    2000-01-01

    This paper briefly describes the characteristics of CF-62 steel material,explains the stress corrosion mechanisms,restriction factors and makes a comprehensive stress analysis for spherical tank,from which,the medium critical pressure is derived.Based upon the relationship between steel hardness and critical value of H2S concentration which causes stress corrosion,the safety control conditions are developed,while countermeasures of general spherical tank are presented.

  19. AN ASSESSMENT OF THE SERVICE HISTORY AND CORROSION SUSCEPTIBILITY OF TYPE IV WASTE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B

    2008-09-18

    Type IV waste tanks were designed and built to store waste that does not require auxiliary cooling. Each Type IV tank is a single-shell tank constructed of a steel-lined pre-stressed concrete tank in the form of a vertical cylinder with a concrete domed roof. There are four such tanks in F-area, Tanks 17-20F, and four in H-Area, Tanks 21-24H. Leak sites were discovered in the liners for Tanks 19 and 20F in the 1980's. Although these leaks were visually observed, the investigation to determine the mechanism by which the leaks had occurred was not completed at that time. Therefore, a concern was raised that the same mechanism which caused the leak sites in the Tanks in F-area may also be operable in the H-Area tanks. Data from the construction of the tanks (i.e., certified mill test reports for the steel, no stress-relief), the service history (i.e., waste sample data, temperature data), laboratory tests on actual wastes and simulants (i.e., electrochemical testing), and the results of the visual inspections were reviewed. The following observations and conclusions were made: (1) Comparison of the compositional and microstructural features indicate that the A212 material utilized for construction of the H-Area tanks are far more resistant to SCC than the A285 materials used for construction of the F-Area tanks. (2) A review of the materials of construction, temperature history, service histories concluded that F-Area tanks likely failed by caustic stress corrosion cracking. (3) The environment in the F-Area tanks was more aggressive than that experienced by the H-Area tanks. (4) Based on a review of the service history, the H-Area tanks have not been exposed to an environment that would render the tanks susceptible to either nitrate stress corrosion cracking (i.e., the cause of failures in the Type I and II tanks) or caustic stress corrosion cracking. (5) Due to the very dilute and uninhibited solutions that have been stored in Tank 23H, vapor space corrosion

  20. Use of electrochemical potential noise to detect initiation and propagation of stress corrosion cracks in a 17-4 PH steel

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rodriguez, J.G. [UAEM, Cuernavaca (Mexico); Salinas-Bravo, V.M.; Garcia-Ochoa, E. [Inst. de Investigaciones Electricas, Temixco (Mexico). Dept. de Fisicoquimica Aplicada; Diaz-Sanchez, A. [Inst. Nacional de Investigaciones Nucleares, Toluca (Mexico). Dept. de Materiales

    1997-09-01

    Corrosion potential transients were associated with nucleation and propagation of stress corrosion cracks in a 17-4 precipitation-hardenable (PH) martensitic stainless steel (SS) during slow strain rate tests (SSRT) at 90 C in deaerated sodium chloride (NaCl) solutions, Test solutions included 20 wt% NaCl at pH 3 and 7, similar to normal and faulted steam turbine environments, respectively. Time series were analyzed using the fast Fourier transform method. At the beginning of straining, the consistent noise behavior was perturbed with small potential transients, probably associated with rupture of the surface oxide layer. After yielding, these transients increased in intensity. At maximum load, the transients were still higher in intensity and frequency. These potential transients were related to crack nucleation and propagation. When the steel did not fail by stress corrosion cracking (SCC), such transients were found only at the beginning of the test. The power spectra showed some differences in all cases in roll-off slope and voltage magnitude, but these were not reliable tools to monitor the initiation and propagation of stress corrosion cracks.

  1. Environmental and Material Influences on the Stress-Corrosion Cracking of Steel in H2O–CO–CO2 Solutions

    Directory of Open Access Journals (Sweden)

    J. W. van der Merwe

    2012-01-01

    Full Text Available The stress-corrosion cracking of A516 pressure vessel steel was investigated by the use of slow strain-rate tests. The orientation of samples to the rolling direction was investigated, and it was found that samples machined longitudinal to the rolling direction showed a slightly increased sensitivity to stress corrosion. The temperature variation showed that for different gas mixtures, the maximum sensitivity to stress corrosion was in the region of 45° to 55°C for the 25% CO gas mixture, whereas with higher CO concentrations, this temperature region of maximum sensitivity moved to higher temperatures. Surface finish showed a slight increase in sensitivity to cracking with increased surface roughness. The most significant increase was found with increased total gas pressures and when samples have been exposed to the environment for an extended period. This was as a result of the inhibition of the corrosion reaction by the passivation of the carbon monoxide, which is a time-dependent process.

  2. A preliminary mechanical property and stress corrosion evaluation of VIM-VAR work strengthened and direct aged Inconel 718 bar material

    Science.gov (United States)

    Montano, J. W.

    1987-01-01

    This report presents a preliminary mechanical property and stress corrosion evaluation of double melted (vacuum induction melted (VIM), and vacuum arc remelted (VAR)), solution treated, work strengthened and direct aged Inconel 718 alloy bar (5.50 in. (13.97 cm) diameter). Two sets of tensile specimens, one direct single aged and the other direct double aged, were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 200 ksi (1378.96 MPa) and 168 ksi (1158.33 MPa), respectively, were realized at ambient temperature, for the direct double aged specimen. No failures occurred in the single or double edged longitudinal and transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test showed no mechanical property degradation.

  3. Time exposure studies on stress corrosion cracking of aluminum 2014-T6, aluminum 7075-T651, and titanium 6Al-4V

    Science.gov (United States)

    Terrell, J.

    1972-01-01

    The effect of a constant applied stress in crack initiation of aluminum 2014-T6, 7075-T651 and titanium 6A1-4V has been investigated. Aluminum c-ring specimens (1-inch diameter) and u-band titanium samples were exposed continuously to a 3.5% NaCl solution (pH 6) and organic fluids of ethyl, methyl, and iso-propyl alcohol (reagent purity). Corrosive action was observed to begin during the first and second day of constant exposure as evidenced by accumulation of hydrogen bubbles on the surface of stressed aluminum samples. However, a similar observation was not noted for titanium stressed specimens. Results of this investigation seems to suggest that aluminum 2014-T6, aluminum 7075-T651 are susceptible to stress corrosion cracking in chloride solution (NaCl); while they (both alloys) seem to resist stress corrosion cracking in methyl alcohol, ethyl alcohol, iso-propyl alcohol, and demineralized distilled water. Titanium 6A1-4V showed some evidence of susceptibility to SCC in methanol, while no such susceptibility was exhibited in ethanol, iso-propyl alcohol and demineralized distilled water.

  4. H2S Stress Corrosion Test Research of the Spiral Welded Pipe%螺旋焊管H2S应力腐蚀的试验研究

    Institute of Scientific and Technical Information of China (English)

    王树人

    2001-01-01

    Through the spiral welded pipe H2S stress corrosion testresearch, the article gives out H2S stress corrosion resistance methods of the spiral welded pipe, and proposes some suggestion on the development of China H2S stress corrosion.%通过对螺旋焊管H2S应力腐蚀试验研究,提出了螺旋焊管抗H2S应力腐蚀的几种途径,并对我国H2S应力腐蚀的发展提出了一些建议。

  5. Characterization of the Resistance of Alloy 22 to Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    King, K J; Estill, J C; Rebak, R B

    2002-05-30

    In its current design, the high-level nuclear waste containers include an external layer of Alloy 22 (Ni-22Cr-13Mo-3W-3Fe). Since over their lifetime, the containers may be exposed to multi-ionic aqueous environments, a potential degradation mode of the outer layer could be environmentally assisted cracking (EAC). The objective of the current research was to characterize the effect of applied potential and temperature on the susceptibility of Alloy 22 to EAC in simulated concentrated water (SCW) using the slow strain rate test (SSRT). Results show that Alloy 22 may suffer EAC at applied potentials approximately 400 mV more anodic than the corrosion potential (E{sub corr}).

  6. Preconceptual Design Description for Caustic Recycle Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sevigny, Gary J.; Poloski, Adam P.; Fountain, Matthew S.; Kurath, Dean E.

    2008-04-12

    The U.S. Department of Energy plans to vitrify both high-level and low-activity waste at the Hanford Site in southeastern Washington State. One aspect of the planning includes a need for a caustic recycle process to separate sodium hydroxide for recycle. Sodium is already a major limitation to the waste-oxide loading in the low-activity waste glass to be vitrified at the Waste Treatment Plant, and additional sodium hydroxide will be added to remove aluminum and to control precipitation in the process equipment. Aluminum is being removed from the high level sludge to reduce the number of high level waste canisters produced. A sodium recycle process would reduce the volume of low-activity waste glass produced and minimize the need to purchase new sodium hydroxide, so there is a renewed interest in investigating sodium recycle. This document describes an electrochemical facility for recycling sodium for the WTP.

  7. Photon Differential Splatting for Rendering Caustics

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Schjøth, Lars; Erleben, Kenny;

    2014-01-01

    We present a photon splatting technique which reduces noise and blur in the rendering of caustics. Blurring of illumination edges is an inherent problem in photon splatting, as each photon is unaware of its neighbours when being splatted. This means that the splat size is usually based...... on heuristics rather than knowledge of the local flux density. We use photon differentials to determine the size and shape of the splats such that we achieve adaptive anisotropic flux density estimation in photon splatting. As compared to previous work that uses photon differentials, we present the first method...... where no photons or beams or differentials need to be stored in a map. We also present improvements in the theory of photon differentials, which give more accurate results and a faster implementation. Our technique has good potential for GPU acceleration, and we limit the number of parameters requiring...

  8. Parameters influencing the transgranular stress corrosion cracking behaviour of austenitic stainless steels in systems conveying reactor coolant

    Energy Technology Data Exchange (ETDEWEB)

    Kilian, R.; Wesseling, U. [Framatome ANP (Germany); Wachter, O. [E.ON Kernkraft (Germany); Widera, M. [RWE Power (Germany); Brummer, G. [HEW - (Germany); Ilg, U. [EnBW - (Germany)

    2002-07-01

    During replacement of an auxiliary system in the German PWR KKS (NPP Stade) a damage was detected in a valve housing and in the connected piping both made from stabilised austenitic stainless steel. During operation stagnant conditions are present in this area. Based on the failure analysis chloride induced stress corrosion cracking (SCC) was found as the dominating root cause. In the open literature many cases of corrosion observed in the water/steam interface in valve components as well as in adjacent portions of auxiliary circuits made of un-stabilized stainless steels are mentioned. A common feature of the reported cases is that transgranular cracking was found. Extensive laboratory investigations revealed that non-stabilised austenitic stainless steels are also sensitive to transgranular cracking in boric acid solutions particularly in concentrated solutions. Often these solutions are contaminated with chlorides and/or oxygen is present. Taking into account the literature data the question could arise whether the above mentioned cracking may be also caused by boric acid attack. Thus, for stabilised stainless steels laboratory exposure tests at 80 C in saturated aerated boric acid solution and at 300 C in (at 100 C) saturated, oxygen free boric acid solution have been performed. Double-U-bend specimens and wedge loaded 1T-CT specimens made of Ti- and Nb-stabilised austenitic stainless steels were used. The results revealed no evidence of crack initiation and crack growth. Based on the laboratory results and the literature data an attempt is undertaken to separate parameters influencing chloride induced SCC from the effect of boric acid. (authors)

  9. Stress corrosion cracking of X70 pipeline steel in near-neutral pH soil solution

    Energy Technology Data Exchange (ETDEWEB)

    Fang, B.Y.; Wang, J.Q.; Han, E.H.; Zhu, Z.Y.; Ke, W. [Chinese Academy of Sciences, Shenyang (China). State Key Laboratory for Corrosion and Protection, Inst. of Metal Research

    2004-07-01

    Near-neutral pH stress corrosion cracking (SCC) is characterized by wide transgranular cracks with quasi-cleavage on the fracture surface, and there is usually little evidence of general or lateral corrosion. Near-neutral pH SCC is related to dissolution and hydrogen ingress into steel pipes because discharged atomic hydrogen can enter the steel so that cracks are initiated or grown by a combination of dissolution and hydrogen-embrittlement. In this study, the SCC cracking behaviour of an X70 pipeline was investigated using slow strain rate tests (SSRT) and cyclic loading at high R and low frequency in a near-neutral pH soil solution saturated with 5 per cent carbon dioxide (CO{sub 2}) and 95 per cent nitrogen (N{sub 2}). Potentiodynamic polarization analyses and electrochemical impedance spectrum (EIS) analyses were also conducted in order to examine the effect of the concentration of bicarbonate, bubbled gas and the addition of chloride ions on polarization behaviour. Results of the SSRT tests showed that transgranular SCC occurred in the soil solution. Crack initiation was associated with pitting. The pipe's susceptibility to SCC increased with decreases in applied electrochemical potential and strain rate. Cyclic loading tests showed that crack propagation processes were dominated by SCC. At high R and low frequencies, SCC was observed on fatigued, pre-cracked specimens. Results of the electrochemical tests showed that polarization behaviours were influenced by the concentrations of bicarbonate, bubbled gas, and the addition of chloride ions. It was concluded that the addition of chloride ion can influence film stability on pipeline specimen surfaces. 22 refs., 2 tabs., 8 figs.

  10. Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline

    Directory of Open Access Journals (Sweden)

    LI Wei

    2007-02-01

    Full Text Available A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303g/L NaOH alkaline solution at 85℃ was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

  11. Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline

    Institute of Scientific and Technical Information of China (English)

    LI Wei; LIU Jun-quan; TU Xiao-hui

    2007-01-01

    A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303 g/L NaOH alkaline solution at 85℃ was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

  12. Effects of Stress on Localized Corrosion in Al and Al Alloys

    Science.gov (United States)

    2007-11-02

    radiography, Compressive stress, Low plastic 16. PRICE CODE N/A burnishing 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY...effects of residual compressive stress on IGC were studied using samples treated by low plastic burnishing (LPB), which produces a surface layer with high...9.5 mm diameter hole was drilled through the body and then capped to create the inner cell cavity. A 1.05 x 18.5 mm slot was machined in one side of the

  13. The effects of cold rolling orientation and water chemistry on stress corrosion cracking behavior of 316L stainless steel in simulated PWR water environments

    Science.gov (United States)

    Chen, Junjie; Lu, Zhanpeng; Xiao, Qian; Ru, Xiangkun; Han, Guangdong; Chen, Zhen; Zhou, Bangxin; Shoji, Tetsuo

    2016-04-01

    Stress corrosion cracking behaviors of one-directionally cold rolled 316L stainless steel specimens in T-L and L-T orientations were investigated in hydrogenated and deaerated PWR primary water environments at 310 °C. Transgranular cracking was observed during the in situ pre-cracking procedure and the crack growth rate was almost not affected by the specimen orientation. Locally intergranular stress corrosion cracks were found on the fracture surfaces of specimens in the hydrogenated PWR water. Extensive intergranular stress corrosion cracks were found on the fracture surfaces of specimens in deaerated PWR water. More extensive cracks were found in specimen T-L orientation with a higher crack growth rate than that in the specimen L-T orientation with a lower crack growth rate. Crack branching phenomenon found in specimen L-T orientation in deaerated PWR water was synergistically affected by the applied stress direction as well as the preferential oxidation path along the elongated grain boundaries, and the latter was dominant.

  14. Mitigation of stress corrosion cracking in pressurized water reactor (PWR) piping systems using the mechanical stress improvement process (MSIP{sup R)} or underwater laser beam welding

    Energy Technology Data Exchange (ETDEWEB)

    Rick, Grendys; Marc, Piccolino; Cunthia, Pezze [Westinghouse Electric Company, LLC, New York (United States); Badlani, Manu [Nu Vision Engineering, New York (United States)

    2009-04-15

    A current issue facing pressurized water reactors (PWRs) is primary water stress corrosion cracking (PWSCC) of bi metallic welds. PWSCC in a PWR requires the presence of a susceptible material, an aggressive environment and a tensile stress of significant magnitude. Reducing the potential for SCC can be accomplished by eliminating any of these three elements. In the U.S., mitigation of susceptible material in the pressurizer nozzle locations has largely been completed via the structural weld overlay (SWOL) process or NuVision Engineering's Mechanical Stress Improvement Process (MSIP{sup R)}, depending on inspectability. The next most susceptible locations in Westinghouse designed power plants are the Reactor Vessel (RV) hot leg nozzle welds. However, a full SWOL Process for RV nozzles is time consuming and has a high likelihood of in process weld repairs. Therefore, Westinghouse provides two distinctive methods to mitigate susceptible material for the RV nozzle locations depending on nozzle access and utility preference. These methods are the MSIP and the Underwater Laser Beam Welding (ULBW) process. MSIP applies a load to the outside diameter of the pipe adjacent to the weld, imposing plastic strains during compression that are not reversed after unloading, thus eliminating the tensile stress component of SCC. Recently, Westinghouse and NuVision successfully applied MSIP on all eight RV nozzles at the Salem Unit 1 power plant. Another option to mitigate SCC in RV nozzles is to place a barrier between the susceptible material and the aggressive environment. The ULBW process applies a weld inlay onto the inside pipe diameter. The deposited weld metal (Alloy 52M) is resistant to PWSCC and acts as a barrier to prevent primary water from contacting the susceptible material. This paper provides information on the approval and acceptance bases for MSIP, its recent application on RV nozzles and an update on ULBW development.

  15. Formation of caustics in k-essence and Horndeski theory

    CERN Document Server

    Babichev, Eugeny

    2016-01-01

    We study propagation of waves and appearance of caustics in k-essence and galileon theories. First we show that previously known solutions for travelling waves in k-essence and galileon models correspond to very specific fine-tuned initial conditions. On the contrary, as we demonstrate by the method of characteristics, a generic wave in k-essence ends up with formation of caustics. Finally, we find that any wave solution in pure k-essence is also a solution for a galileon theory with the same k-essence term. Thus in the Horndeski theory formation of caustics is generic. We discuss physical consequences of the caustics formation and possible ways to cure the problem.

  16. Report on Status of Shipment of High Fluence Austenitic Steel Samples for Characterization and Stress Corrosion Crack Testing

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Scarlett R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    The goal of the Mechanisms of Irradiation Assisted Stress Corrosion Cracking (IASCC) task in the LWRS Program is to conduct experimental research into understanding how multiple variables influence the crack initiation and crack growth in materials subjected to stress under corrosive conditions. This includes understanding the influences of alloy composition, radiation condition, water chemistry and metallurgical starting condition (i.e., previous cold work or heat treatments and the resulting microstructure) has on the behavior of materials. Testing involves crack initiation and growth testing on irradiated specimens of single-variable alloys in simulated Light Water Reactor (LWR) environments, tensile testing, hardness testing, microstructural and microchemical analysis, and detailed efforts to characterize localized deformation. Combined, these single-variable experiments will provide mechanistic understanding that can be used to identify key operational variables to mitigate or control IASCC, optimize inspection and maintenance schedules to the most susceptible materials/locations, and, in the long-term, design IASCC-resistant materials. In support of this research, efforts are currently underway to arrange shipment of “free” high fluence austenitic alloys available through Électricité de France (EDF) for post irradiation testing at the Oak Ridge National Laboratory (ORNL) and IASCC testing at the University of Michigan. These high fluence materials range in damage values from 45 to 125 displacements per atom (dpa). The samples identified for transport to the United States, which include nine, no-cost, 304, 308 and 316 tensile bars, were relocated from the Research Institute of Atomic Reactors (RIAR) in Dimitrovgrad, Ulyanovsk Oblast, Russia, and received at the Halden Reactor in Halden, Norway, on August 23, 2016. ORNL has been notified that a significant amount of work is required to prepare the samples for further shipment to Oak Ridge, Tennessee. The

  17. Tracking nanoparticles in an optical microscope using caustics

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Eann A [Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824 (United States); Whelan, Maurice P [Nanotechnology and Molecular Imaging Unit, Institute for Health and Consumer Protection, European Commission DG Joint Research Center, 21021 Ispra (Vatican City State, Holy See,) (Italy)

    2008-03-12

    An elegant method is proposed and demonstrated for tracking the location and movement of nanoparticles in an optical microscope using the optical phenomenon of caustics. A simple and reversible adjustment to the microscope generates caustics several orders of magnitude larger than the particles. The method offers a simple and relatively inexpensive method for visualizing such phenomena as the formation of self-assembled monolayers and the interaction of nanoparticles with chemically functionalized surfaces.

  18. Test report - 241-AN-274 Caustic Pump Control Building

    Energy Technology Data Exchange (ETDEWEB)

    Paintner, G.P.

    1995-05-01

    This Acceptance Test Report documents the test results of test procedure WHC-SD-WM-ATP-135 `Acceptance Test Procedure for the 241-AN- 274 Caustic Pump Control Building.` The objective of the test was to verify that the 241-AN-274 Caustic Pump Control Building functions properly based on design specifications per applicable H-2-85573 drawings and associated ECN`s. The objective of the test was met.

  19. Engineering wavefront caustics trajectories in ${\\cal PT}$-symmetric lattices

    CERN Document Server

    Bender, Nicholas; Kottos, Tsampikos

    2015-01-01

    We utilize caustic theory in ${\\cal PT}-$symmetric lattices to design focusing and curved beam dynamics. We show that the gain and loss parameter in these systems provides an addition degree of freedom which allows for the design of the same caustics trajectories with different intensity distribution in the individual waveguides. Moreover we can create aberration-free focal points at any paraxial distance $z_f$, with anomalously large focal intensity.

  20. The stress corrosion cracking behaviour of heat-treated Al-Zn-Mg-Cu alloy in modified salt spray fog testing

    Energy Technology Data Exchange (ETDEWEB)

    Onoro, J. [Ingenieria y Ciencia de los Materiales, Universidad Politecnica de Madrid, ETS Ingenieros Industriales, Madrid (Spain)

    2010-02-15

    The stress corrosion cracking behaviour of 7075 (Al-Zn-Mg-Cu) alloy have been studied in a salt spray fog chamber with two vapourised aqueous solutions (0 and 5% NaCl). The paper analyses the stress corrosion resistance of 7075 aluminium alloy with several precipitation-ageing heat treatments. The results are compared with that obtained in 3.5% NaCl aqueous solution at 20 C. The salt spray fog testing has permitted a good evaluation of SCC susceptibility in 7075 alloy. All temper conditions studied were susceptible to SCC in the different environments tested. 7075-T6 temper was the most susceptible, while in all the cases studied 7075-T73 temper was the least susceptible. Compared to 7075-T6, 7075-RRA temper improved the resistance against the SCC process, but the mechanical properties obtained were lower. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  1. Caustic Injury In Adults – A Study For 3 Year Period

    Directory of Open Access Journals (Sweden)

    Radenkova-Saeva J.

    2016-10-01

    Full Text Available The aim of the study is to present the results of a 3-year clinico-epidemiological investigation of caustic injury in adults. The study includes 43 patients with acute corrosive ingestion, hospitalized in the Toxicology Clinic, University Hospital “N. I. Pirogov”, Sofia, Bulgaria, for the period 01.01. 2010-31.12.2012. The methods used include: clinical observation and examination, clinical laboratory, imaging, and psychiatric methods and tests. 43 patients between the ages of 22 and 82 with acute corrosive ingestions have been observed. Eleven were male (25.6% and 32 female (74.4%. All ingestions were intentional. Alkaline agents were used by all of the patients. The severity of poisonings varied from moderate to extremely severe. Different complications were seen in 82% of the cases - severe bleeding, perforation, fistula or/and stricture formation. Two of the patients have undergone surgical intervention - coloesophagoplastic - and have recovered completely. The motivation in different age groups was also studied. Psychiatric comorbidity occurred in patients as depressive and schizoaffective disorder, as well as existential crises. Acute corrosive ingestions by alkaline agents cause severe pathology. The severity and complex character of the injuries require good coordination between different medical specialists.

  2. Effect of heat treatment on the stress corrosion resistance of a microalloyed pipeline steel

    Energy Technology Data Exchange (ETDEWEB)

    Albarran, J.L. [UNAM, Inst. de Fisica, Cuernavaca (Mexico); Martinez, L. [UNAM, Inst. de Fisica, Cuernavaca (Mexico)]|[U.A.C., Programa de Corrosion del Golfo de Mexico (Mexico); Lopez, H.F. [Wisconsin Univ., Materials Dept., Milwaukee, WI (United States)

    1999-11-01

    In this work, the effect of heat treating on a pipeline steel exposed to a sulfide stress cracking (SSC) environment was investigated using LEFM compact specimens. In the as-received condition, specimens with crack orientations parallel and normal to the rolling direction were exposed to H{sub 2}S saturated synthetic sea water at an applied stress intensity (K{sub 1}) of 30 MPa{center_dot}m{sup 1/2}. In both cases, crack propagation rates were very close to each other (da/dt = 8.77 x 10{sup -9}m/s). as the microstructure was modified by heat treating, the rates of crack growth exhibited appreciable differences under similar applied stress intensities. In the martensitic (as-quenched) condition, crack growth was relatively fast (da/dt = 4.72 x 10{sup -7}m/s) indicating severe hydrogen embrittlement. In the water sprayed, and in the quenched and tempered conditions, the LEFM specimens exhibited crack arrest events. This, in turn, enabled the determination of threshold stress intensity values (K{sub issc}) for the water sprayed, and for the quenched and tempered conditions of 26 and 32 MPa{center_dot}m{sup 1/2}, respectively. In addition, favourable paths for microcrack growth were found to be provided by globular inclusions and grain boundary precipitates. (Author)

  3. Evaluation of primary water stress corrosion cracking growth rates by using the extended finite element method

    Directory of Open Access Journals (Sweden)

    Sung-Jun Lee

    2015-12-01

    Conclusion: Reliable CGR curves were obtained without complex environmental facilities or a high degree of experimental effort. The proposed method may be used to assess the PWSCC resistance of nuclear components subjected to high residual stresses such as those resulting from dissimilar metal welding parts.

  4. Surface Chemistry and Structural Effects in the Stress Corrosion of Glass and Ceramic Materials.

    Science.gov (United States)

    1986-03-31

    elimination of ’weakened’ siloxane linkages, the creation of a ’ microplastic ’ surface layer, and consequently a more uniform distribution of applied stress...examined the impact toughness of plate glass treated at elevated temperatures with sulfur dioxide and also difluorodichloromethane. They, too, observed an

  5. The Influence of Composition upon Surface Degradation and Stress Corrosion Cracking of the Ni-Cr-Mo Alloys in Wet Hydrofluoric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Crook, P; Meck, N S; Rebak, R B

    2006-12-04

    At concentrations below 60%, wet hydrofluoric acid (HF) is extremely corrosive to steels, stainless steels and reactive metals, such as titanium, zirconium, and tantalum. In fact, only a few metallic materials will withstand wet HF at temperatures above ambient. Among these are the nickel-copper (Ni-Cu) and nickel-chromium-molybdenum (Ni-Cr-Mo) alloys. Previous work has shown that, even with these materials, there are complicating factors. For example, under certain conditions, internal attack and stress corrosion cracking (SCC) are possible with the Ni-Cr-Mo alloys, and the Ni-Cu materials can suffer intergranular attack when exposed to wet HF vapors. The purpose of this work was to study further the response of the Ni-Cr-Mo alloys to HF, in particular their external corrosion rates, susceptibility to internal attack and susceptibility to HF-induced SCC, as a function of alloy composition. As a side experiment, one of the alloys was tested in two microstructural conditions, i.e. solution annealed (the usual condition for materials of this type) and long-range ordered (this being a means of strengthening the alloy in question). The study of external corrosion rates over wide ranges of concentration and temperature revealed a strong beneficial influence of molybdenum content. However, tungsten, which is used as a partial replacement for molybdenum in some Ni-Cr-Mo alloys, appears to render the alloys more prone to internal attack. With regard to HF-induced SCC of the Ni-Cr-Mo alloys, this study suggests that only certain alloys (i.e., those containing tungsten) exhibit classical SCC. It was also discovered that high external corrosion rates inhibit HF-induced SCC, presumably due to rapid progression of the external attack front. With regard to the effects of long-range ordering, these were only evident at the highest test temperatures, where the ordered structure exhibited much higher external corrosion rates than the annealed structure.

  6. Electrochemical properties and stress corrosion cracking of alloys 600, 690, and 800 in solutions containing boric acid and chloride

    Energy Technology Data Exchange (ETDEWEB)

    Bae, J. H.; Won, C. H. [Chungnam Nation Univ., Taejon (Korea, Republic of); Lee, E. H.; Kim, H. P.; Kim, W. C. [KAERI, Taejon (Korea, Republic of)

    2000-10-01

    Electrochemical characteristics and stress corrosion cracking(SCC)of Alloy 600, Alloy 690 and Alloy 800 have been studied in boric acid solution with chloride. Electrochemical characteristics were measured in mixed solution of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C. SCC resistance was predicted with Parameter(P{sub SCC}) including current density ratio obtained at two different scan rates. P{sub SCC} increased with a following sequence: Alloy 600MA, 600TT, 690TT and Alloy 800. SCC test was carried out with C-ring specimens and reverse U-bend(RUB) specimens at 320 .deg. C and 350 .deg. C. Test solutions were mixture of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C and mixture of 27% H{sub 3}BO{sub 3} and 2g/l Cl{sup -} at 350 .deg. C. C-ring specimens test in the solution of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C for 2400hrs did not show SCC. RUB specimen of Alloy600MA and 600TT showed SCC after 1920 hours exposure to the solution of 27% H{sub 3}BO{sub 3} and 0.2g/l Clat 350 .deg. C.

  7. Effect of Travel Speed on the Stress Corrosion Behavior of Friction Stir Welded 2024-T4 Aluminum Alloy

    Science.gov (United States)

    Wang, Wen; Li, Tianqi; Wang, Kuaishe; Cai, Jun; Qiao, Ke

    2016-05-01

    The effect of travel speed on stress corrosion cracking (SCC) behavior of friction stir welded 2024-T4 aluminum alloy was investigated by slow strain rate tensile test. Microstructure and microhardness of the welded joint were studied. The results showed that the size of second phase particles increased with increasing travel speed, and the distribution of second phase particles was much more homogeneous at lower travel speed. The minimum microhardness was located at the boundary of nugget zone and thermomechanically affected zone. In addition, the SCC susceptibility of the friction stir welded joint increased with the increase of travel speed, owing to the size and distribution of second phase particles in the welds. The anodic applied potentials of -700, -650, -600 mV, and cathodic applied potential of -1200 mV facilitated SCC while the cathodic applied potential of -1000 mV improved the SCC resistance. The SCC behavior was mainly controlled by the metal anodic dissolution at the open circuit potential, and hydrogen accelerated metal embrittlement.

  8. Stress corrosion cracking susceptibility of a high strength Mg-7%Gd-5%Y-1%Nd-0.5%Zr alloy

    Directory of Open Access Journals (Sweden)

    S.D. Wang

    2014-12-01

    Full Text Available Through performing the tensile tests with different strain rates in 3.5 wt.% NaCl solution, the stress corrosion cracking (SCC behavior and the effect of strain rate on the SCC susceptibility of an extruded Mg-7%Gd-5%Y-1%Nd-0.5%Zr (EW75 alloy have been investigated. Results demonstrate that the alloy is susceptible to SCC when the strain rate is lower than 5 × 10−6 s−1. At the strain rate of 1 × 10−6 s−1, the SCC susceptibility index (ISCC is 0.96 and the elongation-to-failure (εf is only 0.11%. Fractography indicates that the brittle quasi-cleavage feature is very obvious and become more pronounced with decreasing the strain rate. Further analysis confirms that the cracking mode is predominantly transgranular, but the partial intergranular cracking at some localized area can also occur. Meanwhile, it seems that the crack propagation path is unrelated to the existing phase particles.

  9. The influence of long term use of inhibitors in hydrochloric acid pickling baths on hydrogen induced stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Feser, R.; Friedrich, A.; Scheide, F. [Fachhochschule Suedwestfalen, University of Applied Science, Frauenstuhlweg 31, D-58644 Iserlohn (Germany)

    2002-09-01

    The influence of commercially available inhibitors on the absorption of hydrogen by steel (St 52, StE 460, StE 690, 42CrMo4) in 15% hydrochloric acid was studied. The pickling bath aged continuously due to the chemical reaction with oxidized steel sheets. The H{sup +}- and inhibitor concentration decreased with time. The influence of this ageing process on hydrogen-induced stress corrosion cracking was tested by in-situ tensile tests in the bath solution. With increasing ageing of the bath, the reduction in fracture area was reduced and approached the values measured for non-inhibited acid baths. Furthermore hydrogen permeation was investigated. Permeation current densities rose with increasing ageing of the pickling solution. (Abstract Copyright[2002], Wiley Periodicals, Inc.) [German] Der Einfluss von kommerziell erhaeltlichen Inhibitoren auf die Wasserstoffabsorption von Stahl (St 52, StE 460, StE 690, 42CrMo4) wurde in Salzsaeure untersucht. Die Beizbaeder wurden kontinuierlich durch die chemische Reaktion mit oxidierten Stahlblechen gealtert. Die H{sup +}- und Inhibitorkonzentration nahm mit der Zeit ab. Der Einfluss dieses Alterungsprozesses auf die wasserstoffinduzierte Spannungsrisskorrosion wurde durch in-situ Zugversuche mit Badloesung untersucht. Mit zunehmender Alterung des Bades nahm die Brucheinschnuerung ab und erreichte Werte wie sie auch in der nicht inhibierten Saeure erreicht werden. Weiterhin wurde die Wasserstoff-Permeation untersucht. Die Permeationsstromdichte steigt mit zunehmender Alterung der Beizloesung. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  10. Effects of applied potential on the stress corrosion cracking behavior of 7003 aluminum alloy in acid and alkaline chloride solutions

    Science.gov (United States)

    Zhang, Xiao-yan; Song, Ren-guo; Sun, Bin; Lu, Hai; Wang, Chao

    2016-07-01

    Potentiodynamic polarization tests and slow strain rate test (SSRT) in combination with fracture morphology observations were conducted to investigate the stress corrosion cracking (SCC) behavior of 7003 aluminum alloy (AA7003) in acid and alkaline chloride solutions under various applied potentials ( E a). The results show that AA7003 is to a certain extent susceptible to SCC via anodic dissolution (AD) at open-circuit potential (OCP) and is highly susceptible to hydrogen embrittlement (HE) at high negative E a in the solutions with pH levels of 4 and 11. The susceptibility increases with negative shift in the potential when E a is less than -1000 mV vs. SCE. However, the susceptibility distinctly decreases because of the inhibition of AD when E a is equal to -1000 mV vs. SCE. In addition, the SCC susceptibility of AA7003 in the acid chloride solution is higher than that in the alkaline solution at each potential. Moreover, the effect of hydrogen on SCC increases with increasing hydrogen ion concentration.

  11. Stress corrosion cracking behaviour in welded X-70 linepipe steel under near-neutral pH conditions

    Energy Technology Data Exchange (ETDEWEB)

    Adeleke, A.H.; Luo, J.L.; Ivey, D.G. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2005-07-01

    This study examined the relationship between the near neutral pH stress corrosion cracking (SCC) resistance and the yield strength of pipelines steels. In particular, double-edge-notched flat tensile samples of X70 steel were used for both slow strain-rate testing (SSRT) and cyclic loading testing with the notch located in the zone of interest. This included the weld metal (WM), base metal (BM) and heat-affected zone (HAZ). In all samples, the mode of failure was mostly transgranular with cleavage facets around the edges of the fracture surface. One of the objectives of this study was to better understand the microstructural effect of the relationship. The 3 main parameters that were used to assess the SCC susceptibility in a near-neutral pH environment were the elongation ratio, the estimated percentage of the fracture surface that showed brittle fractures, and the relative crack growth at a given exposure time. It was shown that resistance to near-neutral pH SCC depends greatly on the microstructure of the pipeline steels. Fine-grained bainite and ferrite structured steels were found to have a much better combination of strength and SCC resistance compared to ferrite and pearlite structures. The high-to-low sensitivity ranking of the X70 linepipe steel to SCC was established to be: WM is greater than HAZ which is greater than BM. 20 refs., 1 tab., 9 figs.

  12. Effect of deteriorated microstructures on stress corrosion cracking of X70 pipeline steel in acidic soil environment

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to investigate stress corrosion cracking (SCC) of X70 pipeline steel and its weld joint area in acidic soil environmeat in China,two simulating methods were used: one was to obtain bad mierostructures in heat affected zone by annealing at 1300℃ for 10 rain and then,quenching in water; the other was to get different simulating solutions of acidic soil in Yingtan in southeast China.The SCC susceptibilities of X70 pipeline steel before and after quenching in the simulating solutions were analyzed using slow stain rate test (SSRT) and poteatiodynamic polarization technique to investigate the SCC electrochemical mechanism of different mierostruetures further.The results show that SCC appears in the original mierostrueture and the quenched mierostructure as the polarization potential decreases.Hydrogen revolution accelerates SCC of the two tested materials within the range of-850 mV to -1200 mV vs.SCE.Microstructural hardening and grain coarsening also increase SCC.The SCC mechanisms are different,anodic dissolution is the key of causing SCC as the polarization potential is higher than the null eurreat potential,and hydrogen embrittlemeat will play a more important role to SCC as the polarization potential lower than the null current potential.

  13. Illuminating Hot Jupiters in caustic crossing

    CERN Document Server

    Sajadian, Sedighe

    2010-01-01

    In recent years a large number of Hot Jupiters orbiting in a very close orbit around the parent stars have been explored with the transit and doppler effect methods. Here in this work we study the gravitational microlensing effect of a binary lens on a parent star with a Hot Jupiter revolving around it. Caustic crossing of the planet makes enhancements on the light curve of the parent star in which the signature of the planet can be detected by high precision photometric observations. We use the inverse ray shooting method with tree code algorithm to generate the combined light curve of the parent star and the planet. In order to investigate the probability of observing the planet signal, we do a Monte-Carlo simulation and obtain the observational optical depth of $\\tau \\sim 10^{-8}$. We show that about ten years observations of Galactic Bulge with a network of telescopes will enable us detecting about ten Hot Jupiter with this method. Finally we show that the observation of the microlensing event in infra-re...

  14. Assessment of ultrasonic techniques for characterization of stress corrosion cracks in SG partition stubs

    Energy Technology Data Exchange (ETDEWEB)

    Sartre, B.; Banchet, J. [AREVA NP, Saint-Marcel (France); Moras, D.; Bastin, P. [Intercontrole, Rungis (France); Beroni, C. [EDF/CEIDRE, Saint-Denis (France)

    2006-07-01

    Studies by EDF and AREVA NP on Inconel zones have identified the Inconel 600 partition stubs of steam generators as potential areas of SCC, on the hot leg side. Decision was made to perform an expert assessment using ultrasonic testing (UT) techniques to be applied on the whole area of the stub showing penetrant testing (PT) techniques indications. UT techniques, probes and tools were then developed for that purpose. The aim is to size shallow defects, sizing capacity being maintained for defects propagated to a half-thickness. Although no formal qualification was required, the development was performed in view of a performance demonstration. Three mock-ups were manufactured by AREVA NP: two welded mock-ups with machined defects, surface condition and geometry representative of the ''envelope'' of situations likely to be found on the SG; one mock-up, with representative corrosion cracks Development was carried out in two phases: development of techniques and specification of probes and tooling, then development of tools, industrialization of probes, development of procedures, personnel training and performance demonstration. The basic inspection relied on TOFDT, with a contact probe; frequencies, PCS and dimensions were optimised using the results from the mock-ups. Three sets of transducers were defined: a HF transducer for flaw sizes close to the critical size, another HF transducer, with lower PCS for smaller defects, both transducers for material whose permeability was equivalent to that of the mock-ups; anticipating less permeable materials, a MF probe was added. Tests having shown that these transducers did not cover the whole plate thickness, a back-up phased-array probe was selected to scan the plate beyond halfthickness. For a better access under the TSP, a focused transducer was also added to complete the previous set. All of these transducers were operated in immersion, with the same tool: a COBRA type arm which positioned the probes

  15. Effect of solution pH on the electrochemical polarization and stress corrosion cracking of Alloy 690 in 5 M NaCl at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.Y. [Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu 300, Taiwan (China); Chou, L.B. [Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu 300, Taiwan (China); Shih, H.C. [Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu 300, Taiwan (China)]. E-mail: hcshih@mse.nthu.edu.tw

    2005-04-15

    The effect of solution pH on the electrochemical polarization and stress corrosion cracking behaviors of the nickel-based Alloy 690 were investigated in this paper. An experimental, potential-pH diagram was constructed for Alloy 690 in a concentrated (5 M) sodium chloride (NaCl) solution at room temperature ({approx}25 deg. C), using a cyclic polarization method. The domains of immunity, general corrosion, passivation, and pitting in 5 M NaCl solutions were defined. At pH >4, the passive region subdivided into areas of perfect passivation, imperfect passivation, and pitting. After anodic polarization, the surface of each specimen was carefully examined metallographically. Pitting corrosion was observed over the entire pH range investigated (0.3-8.52) but general corrosion predominated at lower pH values (<3). On the other hand, the mechanical properties, such as ultimate tensile strength (UTS), fracture strain (FS) and the reduction in area (RA) measured by the slow strain rate test (SSRT), decreased significantly at pH <3. The SSRT results are consistent with fractography and side-view observations of the tested specimens by scanning electron microscopy (SEM)

  16. Evaluation of stress corrosion of duplex stainless steel overlay%双相不锈钢堆焊层应力腐蚀性能评价

    Institute of Scientific and Technical Information of China (English)

    王晶; 张亦良; 仇飞; 吴道文

    2013-01-01

    为防止换热器等设备发生应力腐蚀,工程上试采用在与腐蚀介质接触的表面堆焊2205双相不锈钢.为探索方案的应用范畴与可行性,对两种焊接工艺(自动焊及焊条电弧焊)、3种工程上常见腐蚀环境(饱和硫化氢、氯化镁、氯化钙),通过恒负荷拉伸试验方法及断口微观分析手段,综合评价其应力腐蚀性能,并根据试验结果建立应力-寿命数学模型.结果表明,饱和H2S环境中恒负荷拉伸门槛值σth自动焊为0.45ReL、焊条电弧焊为0.4ReL,二者相差17%.氯化钙环境中0.9ReL应力下96 h试验后所有试样完好,显示出优良的抗氯化钙应力腐蚀能力.而该材料则不适于在沸腾氯化镁环境下工作.%In order to prevent stress corrosion in petrochemical facilities, 2205 duplex stainless steel was deposited on the surface contacted with the corrosive media in projects. In order to explore the application scope and feasibility of the solution, two welding processes ( automatic welding and manual welding) , three kinds of common corrosion environment ( saturated hydrogen sulfide, magnesium chloride, calcium chloride) were used to evaluate its stress corrosion comprehensively at the constant tensile load based on the microanalysis of fracture, and the mathematical model of stress-life was established based on the experimental results. The results indicate that the constant tensile load threshold is 0.45 ReL for automatic welding and 0.4 ReL for manual welding in saturated H2S environment, and there is an error of 17% between them. All the samples are good after 96 hours in 0. 9 ReL stress test with the calcium chloride environment , which shows the excellent resistance to chloride stress corrosion. But the coating cannot be used in boiling magnesium chloride environment.

  17. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  18. Critical Curves and Caustics of Triple-lens Models

    Science.gov (United States)

    Daněk, Kamil; Heyrovský, David

    2015-06-01

    Among the 25 planetary systems detected up to now by gravitational microlensing, there are two cases of a star with two planets, and two cases of a binary star with a planet. Other, yet undetected types of triple lenses include triple stars or stars with a planet with a moon. The analysis and interpretation of such events is hindered by the lack of understanding of essential characteristics of triple lenses, such as their critical curves and caustics. We present here analytical and numerical methods for mapping the critical-curve topology and caustic cusp number in the parameter space of n-point-mass lenses. We apply the methods to the analysis of four symmetric triple-lens models, and obtain altogether 9 different critical-curve topologies and 32 caustic structures. While these results include various generic types, they represent just a subset of all possible triple-lens critical curves and caustics. Using the analyzed models, we demonstrate interesting features of triple lenses that do not occur in two-point-mass lenses. We show an example of a lens that cannot be described by the Chang-Refsdal model in the wide limit. In the close limit we demonstrate unusual structures of primary and secondary caustic loops, and explain the conditions for their occurrence. In the planetary limit we find that the presence of a planet may lead to a whole sequence of additional caustic metamorphoses. We show that a pair of planets may change the structure of the primary caustic even when placed far from their resonant position at the Einstein radius.

  19. Environmental Degradation of Materials: Surface Chemistry Related to Stress Corrosion Cracking

    Science.gov (United States)

    Schwarz, J. A.

    1985-01-01

    Parallel experiments have been performed in order to develop a comprehensive model for stress cracking (SCC) in structural materials. The central objective is to determine the relationship between the activity and selectivity of the microstructure of structural materials to their dissolution kinetics and experimentally measured SCC kinetics. Zinc was chosen as a prototype metal system. The SCC behavior of two oriented single-crystal disks of zinc in a chromic oxide/sodium sulfate solution (Palmerton solution) were determined. It was found that: (1) the dissolution rate is strongly (hkil)-dependent and proportional to the exposure time in the aggressive environment; and (2) a specific slip system is selectively active to dissolution under applied stress and this slip line controls crack initiation and propagation. As a precursor to potential microgrvity experiments, electrophoretic mobility measurements of zinc particles were obtained in solutions of sodium sulfate (0.0033 M) with concentrations of dissolved oxygen from 2 to 8 ppm. The equilibrium distribution of exposed oriented planes as well as their correlation will determine the particle mobility.

  20. Report of the US Nuclear Regulatory Commission Piping Review Committee. Volume 1. Investigation and evaluation of stress corrosion cracking in piping of boiling water reactor plants

    Energy Technology Data Exchange (ETDEWEB)

    1984-08-01

    IGSCC in BWR piping is occurring owing to a combination of material, environment, and stress factors, each of which can affect both the initiation of a stress-corrosion crack and the rate of its subsequent propagation. In evaluating long-term solutions to the problem, one needs to consider the effects of each of the proposed remedial actions. Mitigating actions to control IGSCC in BWR piping must be designed to alleviate one or more of the three synergistic factors: sensitized material, the convention BWR environment, and high tensile stresses. Because mitigating actions addressing each of these factors may not be fully effective under all anticipated operating conditions, mitigating actions should address two and preferably all three of the causative factors; e.g., material plus some control of water chemistry, or stress reversal plus controlled water chemistry.

  1. Wavefronts and caustic associated with Durnin’s beams

    Science.gov (United States)

    de Jesús Cabrera-Rosas, Omar; Espíndola-Ramos, Ernesto; Alejandro Juárez-Reyes, Salvador; Julián-Macías, Israel; Ortega-Vidals, Paula; Silva-Ortigoza, Gilberto; Silva-Ortigoza, Ramón; Sosa-Sánchez, Citlalli Teresa

    2017-01-01

    The aim of the present work is to give a geometrical characterization of Durnin’s beams. That is, we compute the wavefronts and caustic associated with the nondiffracting solutions to the scalar wave equation introduced by Durnin. To this end, first we show that in an isotropic optical medium \\psi ({r},t)={{{e}}}{{i}[{k}0S({r})-ω t]} is an exact solution of the wave equation, if and only if, S is a solution of both the eikonal and Laplace equations, then from one and two-parameter families of this type of solution and the superposition principle we define new solutions of the wave equation, in particular we show that the ideal nondiffracting beams are one example of this type of construction in free space. Using this fact, the wavefronts and caustic associated with those beams are computed. We find that their caustic has only one branch, which is invariant under translations along the direction of evolution of the beam. Finally, the Bessel beam of order m is worked out explicitly and we find that it is characterized by wavefronts that are deformations of conical ones and the caustic is an infinite cylinder of radius proportional to m. In the case m = 0, the wavefronts are cones and the caustic degenerates into an infinite line.

  2. Effect of asphericity in caustic mass estimates of galaxy clusters

    CERN Document Server

    Svensmark, Jacob; Hansen, Steen H

    2014-01-01

    The caustic technique of mass estimation of galaxy clusters relies on the assumption of spherical symmetry, which is not always a valid assumption. Here we demonstrate the effect of spatial anisotropy of galaxy clusters on the inferred caustic mass profiles by considering particle data from dark matter N-body simulations. We find a factor of ~3 discrepancy between major and minor axis mass estimates in ellipsoidal clusters within the virial radius Rv, and up to ~5 within 3 Rv. We also find filaments to influence caustic mass estimates at a comparable magnitude. By stacking halos to align their principal axes we find that a line of sight along the major axis overestimates the caustic mass of galaxy clusters, as well as a line of sight along the minor axis underestimates it. The mass discrepancy between the major and minor axis is a factor of 2.47, 2.97 and 3.95 at 1, 2 and 3 Rv for virial masses Mv = [1,2] x 10^{14} Msun/h, and $(30-35)\\%$ larger for Mv > 2 x 10^{14} Msun/h. Furthermore, the caustic mass is ov...

  3. Stress Corrosion Cracking Behavior of Multipass TIG-Welded AA2219 Aluminum Alloy in 3.5 wt pct NaCl Solution

    Science.gov (United States)

    Venugopal, A.; Sreekumar, K.; Raja, V. S.

    2012-09-01

    The stress corrosion cracking (SCC) behavior of the AA2219 aluminum alloy in the single-pass (SP) and multipass (MP) welded conditions was examined and compared with that of the base metal (BM) in 3.5 wt pct NaCl solution using a slow-strain-rate technique (SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both the BM and welded joints. The results showed that the ductility ratio ( ɛ NaCl/( ɛ air) was 0.97 and 0.96, respectively, for the BM and MP welded joint, and the same was marginally reduced to 0.9 for the SP welded joint. The fractographic examination of the failed samples revealed a typical ductile cracking morphology for all the base and welded joints, indicating the good environmental cracking resistance of this alloy under all welded conditions. To understand the decrease in the ductility of the SP welded joint, preexposure SSRT followed by microstructural observations were made, which showed that the decrease in ductility ratio of the SP welded joint was caused by the electrochemical pitting that assisted the nucleation of cracks in the form of corrosion induced mechanical cracking rather than true SCC failure of the alloy. The microstructural examination and polarization tests demonstrated a clear grain boundary (GB) sensitization of the PMZ, resulting in severe galvanic corrosion of the SP weld joint, which initiated the necessary conditions for the localized corrosion and cracking along the PMZ. The absence of PMZ and a refined fusion zone (FZ) structure because of the lesser heat input and postweld heating effect improved the galvanic corrosion resistance of the MP welded joint greatly, and thus, failure occurred along the FZ.

  4. Origins of Negative Strain Rate Dependence of Stress Corrosion Cracking Initiation in Alloy 690, and Intergranular Crack Formation in Thermally Treated Alloy 690

    Science.gov (United States)

    Kim, Young Suk; Kim, Sung Soo

    2016-09-01

    We show that enhanced stress corrosion cracking (SCC) initiation in cold-rolled Alloy 690 with decreasing strain rate is related to the rate of short-range ordering (SRO) but not to the time-dependent corrosion process. Evidence for SRO is provided by aging tests on cold-rolled Alloy 690 at 623 K and 693 K (350 °C and 420 °C), respectively, which demonstrate its enhanced lattice contraction and hardness increase with aging temperature and time, respectively. Secondary intergranular cracks formed only in thermally treated and cold-rolled Alloy 690 during SCC tests, which are not SCC cracks, are caused by its lattice contraction by SRO before SCC tests but not by the orientation effect.

  5. Assessment of susceptibility of Type 304 stainless steel to intergranular stress corrosion cracking in simulated Savannah River Reactor environments

    Energy Technology Data Exchange (ETDEWEB)

    Ondrejcin, R.S.; Caskey, C.R. Jr.

    1989-12-01

    Intergranular stress corrosion cracking (IGSCC) of Type 304 stainless steel rate tests (CERT) of specimens machined was evaluated by constant extension from Savannah River Plant (SRP) decontaminated process water piping. Results from 12 preliminary CERT tests verified that IGSCC occurred over a wide range of simulated SRP envirorments. 73 specimens were tested in two statistical experimental designs of the central composite class. In one design, testing was done in environments containing hydrogen peroxide; in the other design, hydrogen peroxide was omitted but oxygen was added to the environment. Prediction equations relating IGSCC to temperature and environmental variables were formulated. Temperature was the most important independent variable. IGSCC was severe at 100 to 120C and a threshold temperature between 40C and 55C was identified below which IGSCC did not occur. In environments containing hydrogen peroxide, as in SRP operation, a reduction in chloride concentration from 30 to 2 ppB also significantly reduced IGSCC. Reduction in sulfate concentration from 50 to 7 ppB was effective in reducing IGSCC provided the chloride concentration was 30 ppB or less and temperature was 95C or higher. Presence of hydrogen peroxide in the environment increased IGSCC except when chloride concentration was 11 ppB or less. Actual concentrations of hydrogen peroxide, oxygen and carbon dioxide did not affect IGSCC. Large positive ECP values (+450 to +750 mV Standard Hydrogen Electrode (SHE)) in simulated SRP environments containing hydrogen peroxide and were good agreement with ECP measurements made in SRP reactors, indicating that the simulated environments are representative of SRP reactor environments. Overall CERT results suggest that the most effective method to reduce IGSCC is to reduce chloride and sulfate concentrations.

  6. Caustics and Rogue Waves in an Optical Sea

    CERN Document Server

    Mathis, Amaury; Toenger, Shanti; Dias, Frederic; Genty, Goery; Dudley, John M

    2015-01-01

    There are many examples in physics of systems showing rogue wave behaviour, the generation of high amplitude events at low probability. Although initially studied in oceanography, rogue waves have now been seen in many other domains, with particular recent interest in optics. Although most studies in optics have focussed on how nonlinearity can drive rogue wave emergence, purely linear effects have also been shown to induce extreme wave amplitudes. In this paper, we report a detailed experimental study of linear rogue waves in an optical system, using a spatial light modulator to impose random phase structure on a coherent optical field. After free space propagation, different random intensity patterns are generated, including partially-developed speckle, a broadband caustic network, and an intermediate pattern with characteristics of both speckle and caustic structures. Intensity peaks satisfying statistical criteria for rogue waves are seen especially in the case of the caustic network, and are associated w...

  7. Wavefield extrapolation in caustic-free normal ray coordinates

    KAUST Repository

    Ma, Xuxin

    2012-11-04

    Normal ray coordinates are conventionally constructed from ray tracing, which inherently requires smooth velocity profiles. To use rays as coordinates, the velocities have to be smoothed further to avoid caustics, which is detrimental to the mapping process. Solving the eikonal equation numerically for a line source at the surface provides a platform to map normal rays in complex unsmoothed velocity models and avoid caustics. We implement reverse-time migration (RTM) and downward continuation in the new ray coordinate system, which allows us to obtain efficient images and avoid some of the dip limitations of downward continuation.

  8. 21 CFR 2.110 - Definition of ammonia under Federal Caustic Poison Act.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Definition of ammonia under Federal Caustic Poison... SERVICES GENERAL GENERAL ADMINISTRATIVE RULINGS AND DECISIONS Caustic Poisons § 2.110 Definition of ammonia under Federal Caustic Poison Act. For the purpose of determining whether an article containing...

  9. Electrochemical generation of Fenton's reagent to treat spent caustic wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, H. K.; Nunez, P.; Rodriguez, N.; Guzman, J.

    2009-07-01

    An important wastewater stream from oil refineries is the spent caustic. Caustic solutions are used as scrubbing agent during the desulphurization process to eliminate sulphur an mercaptans from oil and gasses. Spent caustic is classified as DOO3 (reactive sulphide) hazardous waste under the US Resource Conservation and Recovery Act (RCRA). (Author)

  10. Effect of Repair Welding on Electrochemical Corrosion and Stress Corrosion Cracking Behavior of TIG Welded AA2219 Aluminum Alloy in 3.5 Wt Pct NaCl Solution

    Science.gov (United States)

    Venugopal, A.; Sreekumar, K.; Raja, V. S.

    2010-12-01

    The stress corrosion cracking (SCC) behavior of AA2219 aluminum alloy in the as-welded (AW) and repair-welded (RW) conditions was examined and compared with that of the base metal (BM) in 3.5 wt pct NaCl solution using the slow strain rate technique (SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both BM and welded joints. The results show that the ductility ratio ( ɛ NaCl/( ɛ air)) of the BM was close to one (0.97) and reduced to 0.9 for the AW joint. This value further reduced to 0.77 after carrying out one repair welding operation. However, the RW specimen exhibited higher ductility than the single-weld specimens even in 3.5 wt pct NaCl solution. SSRT results obtained using pre-exposed samples followed by post-test metallographic observations clearly showed localized pitting corrosion along the partially melted zone (PMZ), signifying that the reduction in ductility ratio of both the AW and RW joints was more due to mechanical overload failure, caused by the localized corrosion and a consequent reduction in specimen thickness, than due to SCC. Also, the RW joint exhibited higher ductility than the AW joint both in air and the environment, although SCC index (SI) for the former is lower than that of the latter. Fractographic examination of the failed samples, in general, revealed a typical ductile cracking morphology for all the base and welded joints, indicating the good environmental cracking resistance of this alloy. Microstructural examination and polarization tests further demonstrate grain boundary melting along the PMZ, and that provided the necessary electrochemical condition for the preferential cracking on that zone of the weldment.

  11. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    Science.gov (United States)

    Montano, J. W.

    1986-01-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  12. Standard practice for determining the susceptibility of stainless steels and related Nickel-Chromium-Iron Alloys to stress-corrosion cracking in polythionic acids

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers procedures for preparing and conducting the polythionic acid test at room temperature, 22 to 25°C (72 to 77°F), to determine the relative susceptibility of stainless steels or other related materials (nickel-chromiumiron alloys) to intergranular stress corrosion cracking. 1.2 This practice can be used to evaluate stainless steels or other materials in the “as received” condition or after being subjected to high-temperature service, 482 to 815°C (900 to 1500°F), for prolonged periods of time. 1.3 This practice can be applied to wrought products, castings, and weld metal of stainless steels or other related materials to be used in environments containing sulfur or sulfides. Other materials capable of being sensitized can also be tested in accordance with this test. 1.4 This practice may be used with a variety of stress corrosion test specimens, surface finishes, and methods of applying stress. 1.5 This standard does not purport to address all of the safety concerns, if any, ...

  13. Materials Reliability Program Resistance to Primary Water Stress Corrosion Cracking of Alloys 690, 52, and 152 in Pressurized Water Reactors (MRP-111)

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H. [Framatome ANP, Inc., Lynchburg, VA (United States); Fyfitch, S. [Framatome ANP, Inc., Lynchburg, VA (United States); Scott, P. [Framatome ANP, SAS, Paris (France); Foucault, M. [Framatome ANP, SAS, Le Creusot (France); Kilian, R. [Framatome ANP, GmbH, Erlangen (Germany); Winters, M. [Framatome ANP, GmbH, Erlangen (Germany)

    2004-03-01

    Over the last thirty years, stress corrosion cracking in PWR primary water (PWSCC) has been observed in numerous Alloy 600 component items and associated welds, sometimes after relatively long incubation times. Repairs and replacements have generally utilized wrought Alloy 690 material and its compatible weld metals (Alloy 152 and Alloy 52), which have been shown to be very highly resistant to PWSCC in laboratory experiments and have been free from cracking in operating reactors over periods already up to nearly 15 years. It is nevertheless prudent for the PWR industry to attempt to quantify the longevity of these materials with respect to aging degradation by corrosion in order to provide a sound technical basis for the development of future inspection requirements for repaired or replaced component items. This document first reviews numerous laboratory tests, conducted over the last two decades, that were performed with wrought Alloy 690 and Alloy 52 or Alloy 152 weld materials under various test conditions pertinent to corrosion resistance in PWR environments. The main focus of the present review is on PWSCC, but secondary-side conditions are also briefly considered.

  14. An analysis of corrosive substance ingestion of children in eastern Turkey

    OpenAIRE

    Melek, Mehmet; Edirne, Yeşim; Çobanoğlu, Ufuk; CEYLAN, Abdullah; Can, Muhammet

    2013-01-01

    Abstract. In this study, we aimed at describing corrosive substance  ingestion and related problems in Eastern Turkey. This type of injury is still a serious problem to be given a careful attention in our country like the other developing countries. The charts of children managed in our hospital with corrosive substance ingestion in the period of 1996- 2008 were evaluated retrospectively. Gender, age, ingested substance and the volume, symptoms, morbidity of caustic injury were considered in ...

  15. Stress Corrosion Cracking of X80 Pipeline Steel in Near-Neutral pH Environment under Constant Load Tests with and without Preload

    Institute of Scientific and Technical Information of China (English)

    Y.Z. Jia; J.Q. Wang; E.H. Han; W. Ke1

    2011-01-01

    Constant load tests in NS4 solution purged with N2-5%CO2 gas mixture were conducted on American Petroleum Institute (API) X80 pipeline steel applied in the 2nd West-East (;as Pipeline project with and without preload. The results show that cracks could initiate and propagate in X80 pipeline steel in near-neutral pH environment under a constant load condition. The life of crack initiation and propagation increased with decreasing applied stress. Preload did not change its corrosion behavior obviously. However, preload reduced the time for crack initiation.

  16. The use of slow strain rate technique for studying stress corrosion cracking of an advanced silver-bearing aluminum-lithium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frefer, Abdulbaset Ali; Raddad, Bashir S. [Department of Mechanical and Industrial Engineering/Tripoli University, Tripoli (Libya); Abosdell, Alajale M. [Department of Mechanical Engineering/Mergeb University, Garaboli (Libya)

    2013-12-16

    In the present study, stress corrosion cracking (SCC) behavior of naturally aged advanced silver-bearing Al-Li alloy in NaCl solution was investigated using slow strain rate test (SSRT) method. The SSRT’s were conducted at different strain rates and applied potentials at room temperature. The results were discussed based on percent reductions in tensile elongation in a SCC-causing environment over those in air tended to express the SCC susceptbility of the alloy under study at T3. The SCC behavior of the alloy was also discussed based on the microstructural and fractographic examinations.

  17. Online stress corrosion crack and fatigue usages factor monitoring and prognostics in light water reactor components: Probabilistic modeling, system identification and data fusion based big data analytics approach

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish M. [Argonne National Lab. (ANL), Argonne, IL (United States); Jagielo, Bryan J. [Argonne National Lab. (ANL), Argonne, IL (United States); Oakland Univ., Rochester, MI (United States); Iverson, William I. [Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Illinois at Urbana-Champaign, Champaign, IL (United States); Bhan, Chi Bum [Argonne National Lab. (ANL), Argonne, IL (United States); Pusan National Univ., Busan (Korea, Republic of); Soppet, William S. [Argonne National Lab. (ANL), Argonne, IL (United States); Majumdar, Saurin M. [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, Ken N. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-12-10

    Nuclear reactors in the United States account for roughly 20% of the nation's total electric energy generation, and maintaining their safety in regards to key component structural integrity is critical not only for long term use of such plants but also for the safety of personnel and the public living around the plant. Early detection of damage signature such as of stress corrosion cracking, thermal-mechanical loading related material degradation in safety-critical components is a necessary requirement for long-term and safe operation of nuclear power plant systems.

  18. The use of slow strain rate technique for studying stress corrosion cracking of an advanced silver-bearing aluminum-lithium alloy

    Science.gov (United States)

    Frefer, Abdulbaset Ali; Abosdell, Alajale M.; Raddad, Bashir S.

    2013-12-01

    In the present study, stress corrosion cracking (SCC) behavior of naturally aged advanced silver-bearing Al-Li alloy in NaCl solution was investigated using slow strain rate test (SSRT) method. The SSRT's were conducted at different strain rates and applied potentials at room temperature. The results were discussed based on percent reductions in tensile elongation in a SCC-causing environment over those in air tended to express the SCC susceptbility of the alloy under study at T3. The SCC behavior of the alloy was also discussed based on the microstructural and fractographic examinations.

  19. CORROSION ISSUES ASSOCIATED WITH AUSTENITIC STAINLESS STEEL COMPONENTS USED IN NUCLEAR MATERIALS EXTRACTION AND SEPARATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Louthan, M.; Sindelar, R.

    2012-12-17

    This paper illustrated the magnitude of the systems, structures and components used at the Savannah River Site for nuclear materials extraction and separation processes. Corrosion issues, including stress corrosion cracking, pitting, crevice corrosion and other corrosion induced degradation processes are discussed and corrosion mitigation strategies such as a chloride exclusion program and corrosion release testing are also discussed.

  20. DEVELOPMENT OF AN EMAT IN-LINE INSPECTION SYSTEM FOR DETECTION, DISCRIMINATION, AND GRADING OF STRESS CORROSION CRACKING IN PIPELINES

    Energy Technology Data Exchange (ETDEWEB)

    Jeff Aron; Jeff Jia; Bruce Vance; Wen Chang; Raymond Pohler; Jon Gore; Stuart Eaton; Adrian Bowles; Tim Jarman

    2005-02-01

    This report describes prototypes, measurements, and results for a project to develop a prototype pipeline in-line inspection (ILI) tool that uses electromagnetic acoustic transducers (EMATs) to detect and grade stress corrosion cracking (SCC). The introduction briefly provides motivation and describes SCC, gives some background on EMATs and guided ultrasonic waves, and reviews promising results of a previous project using EMATs for SCC. The experimental section then describes lab measurement techniques and equipment, the lab mouse and prototypes for a mule, and scan measurements made on SCC. The mouse was a moveable and compact EMAT setup. The prototypes were even more compact circuits intended to be pulled or used in an ILI tool. The purpose of the measurements was to determine the best modes, transduction, and processing to use, to characterize the transducers, and to prove EMATs and mule components could produce useful results. Next, the results section summarizes the measurements and describes the mouse scans, processing, prototype circuit operating parameters, and performance for SH0 scans. Results are given in terms of specifications--like SNR, power, insertion loss--and parametric curves--such as signal amplitude versus magnetic bias or standoff, reflection or transmission coefficients versus crack depth. Initially, lab results indicated magnetostrictive transducers using both SH0 and SV1 modes would be worthwhile to pursue in a practical ILI system. However, work with mule components showed that SV1 would be too dispersive, so SV1 was abandoned. The results showed that reflection measurements, when normalized by the direct arrival are sensitive to and correlated with SCC. This was not true for transmission measurements. Processing yields a high data reduction, almost 60 to 1, and permits A and C scan display techniques and software already in use for pipeline inspection. An analysis of actual SH0 scan results for SCC of known dimensions showed that length

  1. DEVELOPMENT OF AN EMAT IN-LINE INSPECTION SYSTEM FOR DETECTION, DISCRIMINATION, AND GRADING OF STRESS CORROSION CRACKING IN PIPELINES

    Energy Technology Data Exchange (ETDEWEB)

    Jeff Aron; Jon Gore, Roger Dalton; Stuart Eaton; Adrian Bowles; Owen Thomas; Tim Jarman

    2003-07-01

    This report describes progress, experiments, and results for a project to develop a pipeline inline inspection tool that uses electromagnetic acoustic transducers (EMATs) to detect and grade stress corrosion cracking (SCC). There is a brief introduction that gives background material about EMATs and relevant previous Tuboscope work toward a tool. This work left various choices about the modes and transducers for this project. The experimental section then describes the lab systems, improvements to these systems, and setups and techniques to narrow the choices. Improvements, which involved transducer matching networks, better magnetic biasing, and lower noise electronics, led to improved signal to noise (SNR) levels. The setups permitted transducer characterizations and interaction measurements in plates with man-made cracks, pipeline sections with SCC, and a full pipe with SCC. The latter were done with a moveable and compact EMAT setup, called a lab mouse, which is detailed. Next, the results section justifies the mode and transducer choices. These were for magnetostrictive EMATs and the use of EMAT launched modes: SH0 (at 2.1 MHz-mm) and SV1 (at 3.9 MHz-mm). This section then gives details of measurements on these modes. The measurements consisted of signal to noise ratio, insertion loss, magnetic biasing sensitivities crack reflection and transmission coefficients, beam width, standoff and tilt sensitivities. For most of the measurements the section presents analysis curves, such as reflection coefficient versus crack depth. Some notable results for the chosen modes are: that acceptable SNRs were generated in a pipe with magnetostrictive EMATs, that optimum bias for magnetostrictive transmitters and receivers is magnetic saturation, that crack reflection and transmission coefficients from crack interactions agree with 2 D simulations and seem workable for crack grading, and that the mouse has good waveform quality and so is ready for exhaustive measurement EMAT

  2. Laser Beam Caustic Measurement with Focal Spot Analyser

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Gong, Hui; Bagger, Claus

    2005-01-01

    In industrial applications of high power CO2-lasers the caustic characteristics of the laser beam have great effects on the performance of the lasers. A welldefined high intense focused spot is essential for reliable production results. This paper presents a focal spot analyser that is developed...... for measuring the beam profiles of focused high power CO2-lasers....

  3. Critical Curves and Caustics of Triple-lens Models

    CERN Document Server

    Danek, Kamil

    2015-01-01

    Among the 25 planetary systems detected up to now by gravitational microlensing, there are two cases of a star with two planets, and two cases of a binary star with a planet. Other, yet undetected types of triple lenses include triple stars or stars with a planet with a moon. The analysis and interpretation of such events is hindered by the lack of understanding of essential characteristics of triple lenses, such as their critical curves and caustics. We present here analytical and numerical methods for mapping the critical-curve topology and caustic cusp number in the parameter space of $n$-point-mass lenses. We apply the methods to the analysis of four symmetric triple-lens models, and obtain altogether 9 different critical-curve topologies and 32 caustic structures. While these results include various generic types, they represent just a subset of all possible triple-lens critical curves and caustics. Using the analyzed models, we demonstrate interesting features of triple lenses that do not occur in two-p...

  4. Recognition and Analysis of Corrosion Failure Mechanisms

    Directory of Open Access Journals (Sweden)

    Steven Suess

    2006-02-01

    Full Text Available Corrosion has a vast impact on the global and domestic economy, and currently incurs losses of nearly $300 billion annually to the U.S. economy alone. Because of the huge impact of corrosion, it is imperative to have a systematic approach to recognizing and mitigating corrosion problems as soon as possible after they become apparent. A proper failure analysis includes collection of pertinent background data and service history, followed by visual inspection, photographic documentation, material evaluation, data review and conclusion procurement. In analyzing corrosion failures, one must recognize the wide range of common corrosion mechanisms. The features of any corrosion failure give strong clues as to the most likely cause of the corrosion. This article details a proven approach to properly determining the root cause of a failure, and includes pictographic illustrations of the most common corrosion mechanisms, including general corrosion, pitting, galvanic corrosion, dealloying, crevice corrosion, microbiologically-influenced corrosion (MIC, corrosion fatigue, stress corrosion cracking (SCC, intergranular corrosion, fretting, erosion corrosion and hydrogen damage.

  5. Stress Corrosion Analysis and Control for Equipment in Wet Sulfide Hydrogen Environment%湿硫化氢环境中设备应力腐蚀分析及控制

    Institute of Scientific and Technical Information of China (English)

    邵昀启

    2012-01-01

      文章阐述了硫化氢应力腐蚀机理,分析和探讨了在湿硫化氢环境中影响应力腐蚀的相关因素,并针对这些影响因素提出了相应的防止硫化氢应力腐蚀的技术和工艺措施。%  The article discusses the mechanism of sulfide hydrogen stress corrosion, analysis and discussion of the influencing factors of sulfide hydrogen stress corrosion in wet sulfide hydrogen environment, and in view of these factors put forward a number of technology and process measures to prevent sulfide hydrogen stress corrosion.

  6. Stress corrosion cracking in the vessel closure head penetrations of French PWR`s; Fissuration par corrosion sous contrainte de penetrations de couvercle de cuve de reacteur nucleaire francais a eau pressurisee

    Energy Technology Data Exchange (ETDEWEB)

    Buisine, D.; Cattant, F.; Champredonde, J.; Pichon, C.; Benhamou, C.; Gelpi, A.; Vaindirlis, M.

    1994-01-01

    During a hydrotest in September 1991, part of the statutory decennial in-service inspection, a leak was detected on the vessel head of Bugey 3, which is one of the first 900 MW 3-loop PWR`s in France. This leak was due to a cracked penetration used for a control rod drive mechanism. The investigations performed identified Primary Stress Corrosion Cracking of Alloy 600 as being the origin of this degradation. So a lot of the same design PWR`s are a concern due to this generic problem. In this case, PWSCC was linked to: - hot temperature of the vessel head; - high residual stresses due to the welding process between peripherical penetrations and the vessel head; - sensitivity of forged Alloy 600 used for penetration manufacturing. This following paper will present the cracked analysis based, in particular, on the main results obtained in France on each of these items. These results come from the operating experience, the destructive examinations and the programs which are running on stress analysis and metallurgical characterizations. (authors). 9 figs., 2 tabs.

  7. Stress corrosion of austenitic steels mono and polycrystals in Mg Cl{sub 2} medium: micro fractography and study of behaviour improvements; Corrosion sous contrainte de mono et polycristaux d`aciers inoxydables austenitiques en milieu MgCI{sub 2}: analyse microfractographique et recherche d`ameliorations du comportement

    Energy Technology Data Exchange (ETDEWEB)

    Chambreuil-Paret, A

    1997-09-19

    The austenitic steels in a hot chlorinated medium present a rupture which is macroscopically fragile, discontinuous and formed with crystallographic facets. The interpretation of these facies crystallographic character is a key for the understanding of the stress corrosion damages. The first aim of this work is then to study into details the micro fractography of 316 L steels mono and polycrystals. Two types of rupture are observed: a very fragile rupture which stresses on the possibility of the interatomic bonds weakening by the corrosive medium Mg Cl{sub 2} and a discontinuous rupture (at the micron scale) on the sliding planes which is in good agreement with the corrosion enhanced plasticity model. The second aim of this work is to search for controlling the stress corrosion by the mean of a pre-strain hardening. Two types of pre-strain hardening have been tested. A pre-strain hardening with a monotonic strain is negative. Indeed, the first cracks starts very early and the cracks propagation velocity is increased. This is explained by the corrosion enhanced plasticity model through the intensifying of the local corrosion-deformation interactions. On the other hand, a cyclic pre-strain hardening is particularly favourable. The first micro strains starts later and the strain on breaking point levels are increased. The delay of the starting of the first strains is explained by a surface distortion structure which is very homogeneous. At last, the dislocations structure created in fatigue at saturation is a planar structure of low energy which reduces the corrosion-deformation interactions, source of micro strains. (O.M.) 139 refs.

  8. Corrosion Evaluation and Corrosion Control of Steam Generators

    Energy Technology Data Exchange (ETDEWEB)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M

    2008-06-15

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants.

  9. The effects of thermomechanical processing and annealing on the microstructural evolution and stress corrosion cracking of alloy 690

    Science.gov (United States)

    Miller, Cody A.

    The effects of short-range order (SRO), long-range order (LRO), and plastic strain on the microstructure and stress corrosion cracking (SCC) susceptibility of Ni-Cr-Fe Alloy 690 have been investigated in detail. First, the presence of 1/3{422} and 1/2{311} diffuse intensities in B=[111] and B=[112] selected area diffraction patterns (SADPs), previously believed to indicate the presence of SRO, has been examined in Alloy 690, a Ni-Cr binary alloy, and a number of FCC materials in an effort to determine their source. It is shown that these intensities are not due to SRO, although their source remains somewhat unclear. However, an experiment was conducted that tracked the strong {111} reflections in a B=[112] SADP as the sample was tilted (19°) towards a B=[111] zone axis. Significantly, it was noted that the {111} intensities never fully disappear and that they fall in the 1/3{422} positions within the B=[111] SADP. This indicates that these diffuse intensities are related to reflections that lie in the first order Laue zone (FOLZ) when the zone is aligned along B=[111], although theoretical calculations indicate scattering from these planes into the zero order Laue zone used to form the SADP should not occur. Thus, while calculations are inconsistent with the behavior expected, the diffuse intensities observed in a number of high index zones are consistent with projections of higher order Laue zone reflections into the zero layer, suggesting that the theory is in need of reassessment. Second, the stability of the gamma'-Ni2Cr LRO phase present on the Ni-Cr phase diagram was examined in a Ni-55Cr binary alloy. The results indicate that the gamma'-Ni2Cr phase is indeed metastable, and that the two-phase gamma-Ni + alpha-Cr phase field extends all the way to room temperature. Likewise, the sluggish formation of the gamma'-Ni 2Cr phase appears to occur only over a narrow composition and temperature range. It is speculated that this important phase in more complex

  10. Development and validation of an experimental procedure for studying the biaxial stress corrosion. Application to the systems: alloy-600/air and 316L/MgCl{sub 2}; Developpement et validation d'une procedure experimentale pour l'etude de la corrosion sous contrainte biaxiale. Application aux couples alliage 600 / air et 316L / MgCl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Farre, M.Th

    1998-07-15

    One of the main preoccupation for maintaining EdF's nuclear pressurised water reactors is intergranular stress corrosion cracking of steam generator tubing (alloy 600: NC 15Fe). The most affected areas (first row U-bend and roll transition zone) are in biaxial stress state. The crack propagation is often axial and sometimes circumferential. The actual life prediction criterion for these structures depends on the maximal principal stress. The purpose of this study is to determine whether it is safe to use such a criterion in a case of biaxial stress state. A procedure is proposed and experimentally validated for designing specimen in a controlled biaxial stress state when submitted to traction. Quadrants I an IV of the stress space are the only ones explored. The aim is to use these specimens in order to realize stress corrosion tests in primary water with alloy 600. The procedure involves studying the biaxial behavior of the material. This shows the effect of hardening on the shape of the yield stress surface. The hardening of alloy 600 is mainly kinematic. The yield stress surface becomes concave in the hardening stress direction and flat in the opposite direction. The geometry of the specimen stems from parameterized shape optimisation. An elasto-viscoplastic behavior law is identified for alloy 600. Use of the law for calculating the strain state of one specimen is experimentally validated. This entire procedure has been successfully validated with biaxial stress corrosion cracking tests, using 316L and MgCl{sub 2} boiling at 154 deg C. In this case it is difficult to determine a life time criterion. It is shown that the criterion of the maximal principal stress is invalid in case of a biaxial stress state. (author)

  11. Stress corrosion mechanisms of alloy-600 polycrystals and monocrystals in primary water: effect of hydrogen; Mecanismes de corrosion sous contrainte de l'alliage 600 polycristallin et monocristallin en milieu primaire: role de l'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Foct, F

    1999-01-08

    The aim of this study is to identify the mechanisms involved in Alloy 600 primary water stress corrosion cracking. Therefore, this work is mainly focussed on the two following points. The first one is to understand the influence of hydrogen on SCC of industrial Alloy 600 and the second one is to study the crack initiation and propagation on polycrystals and single crystals. A cathodic potential applied during slow strain rate tests does not affect crack initiation but increases the slow crack growth rate by a factor 2 to 5. Cathodic polarisation, cold work and 25 cm{sup 3} STP/kg hydrogen content increase the slow CGR so that the K{sub ISCC} (and therefore fast CGR) is reached. The influence of hydrogenated primary water has been studied for the first time on Alloy 600 single crystals. Cracks cannot initiate on tensile specimens but they can propagate on pre-cracked specimens. Transgranular cracks present a precise crystallographic aspect which is similar to that of 316 alloy in MgCl{sub 2} solutions. Moreover, the following results improve the description of the cracking conditions. Firstly, the higher the hydrogen partial pressure, the lower the Alloy 600 passivation current transients. Since this result is not correlated with the effect of hydrogen on SCC, cracking is not caused by a direct effect of dissolved hydrogen on dissolution. Secondly, hydrogen embrittlement of Alloy 600 disappears at temperatures above 200 deg.C. Thirdly, grain boundary sliding (GBS) does not directly act on SCC but shows the mechanical weakness of grain boundaries. Regarding the proposed models for Alloy 600 SCC, it is possible to draw the following conclusions. Internal oxidation or absorbed hydrogen effects are the most probable mechanisms for initiation. Dissolution, internal oxidation and global hydrogen embrittlement models cannot explain crack propagation. On the other hand, the Corrosion Enhanced Plasticity Model gives a good description of the SCC propagation. (author)

  12. Corrosion problems and solutions in oil refining and petrochemical industry

    CERN Document Server

    Groysman, Alec

    2017-01-01

    This book addresses corrosion problems and their solutions at facilities in the oil refining and petrochemical industry, including cooling water and boiler feed water units. Further, it describes and analyzes corrosion control actions, corrosion monitoring, and corrosion management. Corrosion problems are a perennial issue in the oil refining and petrochemical industry, as they lead to a deterioration of the functional properties of metallic equipment and harm the environment – both of which need to be protected for the sake of current and future generations. Accordingly, this book examines and analyzes typical and atypical corrosion failure cases and their prevention at refineries and petrochemical facilities, including problems with: pipelines, tanks, furnaces, distillation columns, absorbers, heat exchangers, and pumps. In addition, it describes naphthenic acid corrosion, stress corrosion cracking, hydrogen damages, sulfidic corrosion, microbiologically induced corrosion, erosion-corrosion, and corrosion...

  13. Role of hydrogen in the intergranular cracking mechanism by stress corrosion in primary medium of nickel based alloys 600 and 690; Role de l'hydrogene dans le mecanisme de fissuration intergranulaire par corrosion sous contrainte en milieu primaire des alliages base nickel 600, 690

    Energy Technology Data Exchange (ETDEWEB)

    Odemer, G.; Coudurier, A.; Jambon, F.; Chene, J. [CEA Saclay, Dept. de Physico-Chimie (DEN/DANS/DPC/SCCME/LECA), 91 - Gif sur Yvette (France); Odemer, G.; Coudurier, A.; Chene, J. [Evry Univ., UMR 8587 CNRS / CEA, LAMBE, 91 (France)

    2007-07-01

    The aim of this work is to characterize the sensitivity to hydrogen embrittlement of alloys 600 and 690 in order to better understand the eventual role of hydrogen in the stress corrosion mechanism which affects these alloys when they are exposed in PWR primary medium. (O.M.)

  14. Statistics of Caustics in Large-Scale Structure Formation

    CERN Document Server

    Feldbrugge, Job; van de Weygaert, Rien

    2014-01-01

    The cosmic web is a complex spatial pattern of walls, filaments, cluster nodes and underdense void regions. It emerged through gravitational amplification from the Gaussian primordial density field. Here we infer analytical expressions for the spatial statistics of caustics in the evolving large-scale mass distribution. In our analysis, following the quasi-linear Zeldovich formalism and confined to the 1D and 2D situation, we compute number density and correlation properties of caustics in cosmic density fields that evolve from Gaussian primordial conditions. The analysis can be straightforwardly extended to the 3D situation. We moreover, are currently extending the approach to the non-linear regime of structure formation by including higher order Lagrangian approximations and Lagrangian effective field theory.

  15. Statistics of Caustics in Large-Scale Structure Formation

    Science.gov (United States)

    Feldbrugge, Job L.; Hidding, Johan; van de Weygaert, Rien

    2016-10-01

    The cosmic web is a complex spatial pattern of walls, filaments, cluster nodes and underdense void regions. It emerged through gravitational amplification from the Gaussian primordial density field. Here we infer analytical expressions for the spatial statistics of caustics in the evolving large-scale mass distribution. In our analysis, following the quasi-linear Zel'dovich formalism and confined to the 1D and 2D situation, we compute number density and correlation properties of caustics in cosmic density fields that evolve from Gaussian primordial conditions. The analysis can be straightforwardly extended to the 3D situation. We moreover, are currently extending the approach to the non-linear regime of structure formation by including higher order Lagrangian approximations and Lagrangian effective field theory.

  16. Spectral caustics in laser assisted Breit–Wheeler process

    OpenAIRE

    Nousch, T.; Seipt, D.; Kämpfer, B.; Titov, A. I.

    2016-01-01

    Electron–positron pair production by the Breit–Wheeler process embedded in a strong laser pulse is analyzed. The transverse momentum spectrum displays prominent peaks which are interpreted as caustics, the positions of which are accessible by the stationary phases. Examples are given for the superposition of an XFEL beam with an optical high-intensity laser beam. Such a configuration is available, e.g., at LCLS at present and at European XFEL in near future. It requires a counter propagating ...

  17. The Mechanism and Influencing Factors of Corrosion in a Gas Heating-Furnace

    Institute of Scientific and Technical Information of China (English)

    YANG Zhi-gang; ZHANG Ning-sheng; WU Xin-min

    2005-01-01

    Natural gas should be heated and throttled for the purpose of purification and transportation at the first gas production factory of the Changqing field. The safe use and heat-transfer efficiency of a heating-furnace affect the safe and smooth production of natural gas directly. At gas collecting stations now, no measures of anticorrosion have been adopted in heating furnaces which erode and scale badly.In order to solve the corrosive problem of heating-furnaces, prolong operating life of heating-furnaces,assure safe and smooth production of natural gas, the mechanism and influencing factors of corrosion of the heating-furnace were analyzed and some corresponding measures were brought forward based on a field investigation of usage behavior and present operational status of heating-furnaces at the first gas production factory. The results show that the corrosive ion and soluble CO2 and O2 in water erode metal badly at the condition of being heated. Corrosion of a heating-furnace are mostly oxygen corrosion, corrosive ion corrosion, acid corrosion, iron encrustation corrosion, dry and wet interface corrosion, caustic corrosion, etc; The influencing factors of corrosion mainly include soluble O2 and CO2 in water, pH value, heat loading, corrosive ion, soluble solid (salinity) and non-flowing character of water, etc.

  18. Caustics in Tachyon Matter and Other Born-Infeld Scalars

    CERN Document Server

    Felder, G; Starobinsky, A A; Felder, Gary; Kofman, Lev; Starobinsky, Alexei

    2002-01-01

    We consider scalar Born-Infeld type theories with arbitrary potentials V(T) of a scalar field T. We find that for models with runaway potentials V(T) the generic inhomogeneous solutions after a short transient stage can be very well approximated by the solutions of a Hamilton-Jacobi equation that describes free streaming wave front propagation. The analytic solution for this wave propagation shows the formation of caustics with multi-valued regions beyond them. We verified that these caustics appear in numerical solutions of the original scalar BI non-linear equations. Our results include the scalar BI model with an exponential potential, which was recently proposed as an effective action for the string theory tachyon in the approximation where high-order spacetime derivatives of T are truncated. Since the actual string tachyon dynamics contain derivatives of all orders, the tachyon BI model with an exponential potential becomes inadequate when the caustics develop because high order spatial derivatives of T ...

  19. Caustics and Rogue Waves in an Optical Sea.

    Science.gov (United States)

    Mathis, Amaury; Froehly, Luc; Toenger, Shanti; Dias, Frédéric; Genty, Goëry; Dudley, John M

    2015-08-06

    There are many examples in physics of systems showing rogue wave behaviour, the generation of high amplitude events at low probability. Although initially studied in oceanography, rogue waves have now been seen in many other domains, with particular recent interest in optics. Although most studies in optics have focussed on how nonlinearity can drive rogue wave emergence, purely linear effects have also been shown to induce extreme wave amplitudes. In this paper, we report a detailed experimental study of linear rogue waves in an optical system, using a spatial light modulator to impose random phase structure on a coherent optical field. After free space propagation, different random intensity patterns are generated, including partially-developed speckle, a broadband caustic network, and an intermediate pattern with characteristics of both speckle and caustic structures. Intensity peaks satisfying statistical criteria for rogue waves are seen especially in the case of the caustic network, and are associated with broader spatial spectra. In addition, the electric field statistics of the intermediate pattern shows properties of an "optical sea" with near-Gaussian statistics in elevation amplitude, and trough-to-crest statistics that are near-Rayleigh distributed but with an extended tail where a number of rogue wave events are observed.

  20. Research on Aluminized Steel for Resisting Stress Corrosion Cracking and Hydrogen Embrittlement%渗铝钢抗应力腐蚀开裂及抗氢脆性能研究

    Institute of Scientific and Technical Information of China (English)

    吴昊; 李华飞

    2016-01-01

    以30CrMo钢为母体,对30CrMo钢及其渗铝钢分别进行抗硫化氢应力腐蚀开裂实验、抗氯离子应力腐蚀开裂实验,采用Devanathan双电池技术测量氢的扩散系数。实验结果表明:30CrMo钢渗铝后比渗铝前具有更好的抗硫化氢应力腐蚀开裂、抗氢脆性能;单一氯离子对30CrMo钢及其渗铝钢应力腐蚀开裂性能影响较小。%Using 30CrMo steel as the matrix, resistance to hydrogen sulfide stress corrosion cracking test and resistance to chloride ion stress corrosion cracking test were carried out respectively for 30CrMo steel and its aluminized steel.Using Devanathan double cell technology, and we measured hydrogen diffusion coefficient.Experimental results show that, aluminized steel of 30CrMo has better resistance to hydrogen sulfide stress corrosion cracking and hy-drogen embrittlement, and single chloride ion has little influence on the stress corrosion cracking for 30CrMo steel and its aluminized steel.

  1. Analysis of ray stability and caustic formation in a layered moving fluid medium

    CERN Document Server

    Bergman, David R

    2015-01-01

    Caustic formation occurs within a ray skeleton as optical or acoustic fields propagate in a medium with variable refractive properties and are unphysical, their presence being an artifact of the ray approximation of the field, and methods of correcting the field near a caustic are well known. Differential geometry provides a novel approach to calculating acoustic intensity, assessing ray stability and locating caustics in acoustic ray traces when the properties of medium are completely arbitrary by identifying points on the caustic with conjugate points along various rays. The method of geodesic deviation is applied to the problem of determining ray stability and locating caustics in 2-dimensional acoustic ray traces in a layered moving medium. Specifically, a general treatment of caustic formation in sound ducts and in piecewise continuous media is presented and applied to various idealized and realistic scenarios.

  2. Effects of an expanding caustic ring on a distribution of stars

    Science.gov (United States)

    Chakrabarty, Sankha Subhra; Sikivie, Pierre

    2017-01-01

    In self-similar axially symmetric model of galactic halo, caustic rings lie on the galactic disk and expand on cosmological time scale. We study the motion of a distribution of stars under the gravitational field of an expanding caustic ring. We investigate how the bulk velocities of the stars are affected by the caustic. This work was supported in part by the Heising-Simons Foundation.

  3. Effect of Pre-aging on Stress Corrosion Cracking of Spray-formed 7075 Alloy in Retrogression and Re-aging

    Science.gov (United States)

    Su, Rui-ming; Qu, Ying-dong; You, Jun-hua; de Li, Rong-

    2015-11-01

    The effects of pre-aging in retrogression and re-aging (RRA) treatment on microstructure, mechanical properties, and stress corrosion cracking (SCC) behavior of spray-formed 7075 aluminum alloy were investigated by tensile test, slow strain rate test, and transmission electron microscope. The results show that the under aging (120 °C for 16 h) as the pre-aging in RRA treatment can vastly improve the mechanical properties and the SCC resistance of the alloy, compared with early aging (120 °C for 8 h), peak aging (120 °C for 24 h), and over aging (120 °C for 32 h) treatments, the ultimate tensile strength of the alloy is 782 MPa, which is higher than that for peak aging or conventional RRA treatment; and the SCC resistance of the alloy is also excellent after RRA with under aging as pre-aging.

  4. Improved Stress Corrosion Cracking Resistance and Strength of a Two-Step Aged Al-Zn-Mg-Cu Alloy Using Taguchi Method

    Science.gov (United States)

    Lin, Lianghua; Liu, Zhiyi; Ying, Puyou; Liu, Meng

    2015-12-01

    Multi-step heat treatment effectively enhances the stress corrosion cracking (SCC) resistance but usually degrades the mechanical properties of Al-Zn-Mg-Cu alloys. With the aim to enhance SCC resistance as well as strength of Al-Zn-Mg-Cu alloys, we have optimized the process parameters during two-step aging of Al-6.1Zn-2.8Mg-1.9Cu alloy by Taguchi's L9 orthogonal array. In this work, analysis of variance (ANOVA) was performed to find out the significant heat treatment parameters. The slow strain rate testing combined with scanning electron microscope and transmission electron microscope was employed to study the SCC behaviors of Al-Zn-Mg-Cu alloy. Results showed that the contour map produced by ANOVA offered a reliable reference for selection of optimum heat treatment parameters. By using this method, a desired combination of mechanical performances and SCC resistance was obtained.

  5. Stress corrosion cracking in repair-welded 3.5 NiCrMoV steel in an actual turbine environment

    Energy Technology Data Exchange (ETDEWEB)

    Hitomi, Itoh; Takashi, Shige [Mitsubishi Heavy Industries, Ltd., Takasago Research and Development Center (Japan); Takashi, Momoo [Mitsubishi Heavy Industries, Ltd., Takasago Machinery Works (Japan)

    2001-07-01

    Temporary welding repairs are sometimes needed when damage occurs at the teeth of blade grooves in a low-pressure turbine rotor operated at the dry/wet boundary region. When repair welding has been performed for the 3,5 NiCrMoV steel used in low-pressure turbines, the soundness of the weld must be confirmed. For this reason, a laboratory investigation of susceptibility for stress corrosion cracking (SCC) was conducted for test specimens taken from simulated welds, and then an exposure test was conducted in an actual turbine environment for approximately 7,000 hours. As no SCC initiation was detected and also the propagation was extremely small, repair welding is deemed to be applicable. (author)

  6. Current techniques in acid-chloride corrosion control and monitoring at The Geysers

    Energy Technology Data Exchange (ETDEWEB)

    Hirtz, Paul; Buck, Cliff; Kunzman, Russell

    1991-01-01

    Acid chloride corrosion of geothermal well casings, production piping and power plant equipment has resulted in costly corrosion damage, frequent curtailments of power plants and the permanent shut-in of wells in certain areas of The Geysers. Techniques have been developed to mitigate these corrosion problems, allowing continued production of steam from high chloride wells with minimal impact on production and power generation facilities.The optimization of water and caustic steam scrubbing, steam/liquid separation and process fluid chemistry has led to effective and reliable corrosion mitigation systems currently in routine use at The Geysers. When properly operated, these systems can yield steam purities equal to or greater than those encountered in areas of The Geysers where chloride corrosion is not a problem. Developments in corrosion monitoring techniques, steam sampling and analytical methodologies for trace impurities, and computer modeling of the fluid chemistry has been instrumental in the success of this technology.

  7. Corrosion protection

    Science.gov (United States)

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  8. Study of the sulphide stress corrosion cracking (SSCC) resistance of API SL GR B and X60 pipeline steels. Evaluacion de la resistencia al agrietamiento por corrosion-tension en medios sulfhidricos (SSCC) de aceros para tuberias Calidad API 5L Grados B y X60

    Energy Technology Data Exchange (ETDEWEB)

    Bao-Iturbe, C. (Babcock and Wilcox Espaola. S.A. Bilbao (Spain)); Gutierrez de Saiz-Solabarria (Univ. Pais Vasco. Departamento Ingenieria Metalurgica y Control de Materiales. Bilbao (Spain))

    1993-01-01

    A study of the sulphide stress corrosion cracking resistance at room temperature of API 5L Cr B and X60 pipeline steels has been carried out. The theoretical mechanisms in order to explain these phenomena and several operational failures of pipeline steel due to SSCC have been reviewed and the National Association of Corrosion Engineers (NACE) standard concerning SSCC has been described. The main factors of influence of the SSCC have been analysed, results are presented and conclusions are elaborated. (Author) 32 ref.

  9. NUMERICAL SIMULATION RESEARCH FOR CORROSION EXPANSION STRESS OF REINFORCED CONCRETE%钢筋混凝土锈蚀膨胀力的数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    李悦; 颜超; 辜中伟

    2013-01-01

    It is a key point in current research of concrete durability to calculate and analyze the expansion stress generated due to corrosion of steel bars in reinforced concrete. Considering the uneven rust on steel bars in reinforced concrete, finite element analysis software ABAQUS is used for numerical simulation of stress in concrete due to rusting of steel bar and distribution law of the main tensile stress of concrete is summarized.%计算分析钢筋混凝土中钢筋锈蚀量产生的膨胀应力是目前混凝土耐久性研究的重点问题.考虑混凝土中钢筋的不均匀锈蚀现象,应用有限元分析软件ABAQUS对钢筋锈蚀引起的混凝土内应力进行数值模拟,总结混凝土主拉应力的分布规律.

  10. Influence of plastic strain localization on the stress corrosion cracking of austenitic stainless steels; Influence de la localisation de la deformation plastique sur la CSC d'aciers austenitiques inoxydables

    Energy Technology Data Exchange (ETDEWEB)

    Cisse, S.; Tanguy, B. [CEA Saclay, DEN, SEMI, 91 - Gif-sur-Yvette (France); Andrieu, E.; Laffont, L.; Lafont, M.Ch. [Universite de Toulouse. CIRIMAT, UPS/INPT/CNRS, 31 - Toulous (France)

    2010-03-15

    The authors present a research study of the role of strain localization on the irradiation-assisted stress corrosion cracking (IASCC) of vessel steel in PWR-type (pressurized water reactor) environment. They study the interaction between plasticity and intergranular corrosion and/or oxidation mechanisms in austenitic stainless steels with respect to sublayer microstructure transformations. The study is performed on three austenitic stainless grades which have not been sensitized by any specific thermal treatment: the A286 structurally hardened steel, and the 304L and 316L austenitic stainless steels

  11. Review of studies on corrosion of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    ZENG Rong-chang; ZHANG jin; HUANG Wei-jiu; W. DIETZEL; K. U. KAINER; C. BLAWERT; KE Wei

    2006-01-01

    This review provided some recent progress of the research on corrosion mechanisms of magnesium and its alloys and a basis for follow-on research. Galvanic corrosion,pitting corrosion,intergranular corrosion (IGC),filiform corrosion,crevice corrosion,stress corrosion cracking (SCC),and corrosion fatigue (CF) were discussed. The influence of metallurgical factors such as alloying elements,microstructure and secondary phases,processing factors such as heat treatment and weld,and environmental factors including temperature,relative humidity,solution pH values and concentration on corrosion were discussed. In particular,a mechanism of pitting corrosion caused by AlMn particles was proposed. The corrosion properties of AZ91D weld material were investigated.

  12. Corrosion Engineering.

    Science.gov (United States)

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  13. General Corrosion and Localized Corrosion of Waste Package Outer Barrier

    Energy Technology Data Exchange (ETDEWEB)

    K.G. Mon

    2004-10-01

    The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

  14. Corrosion sensor

    Science.gov (United States)

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  15. Fatigue and Corrosion in Metals

    CERN Document Server

    Milella, Pietro Paolo

    2013-01-01

    This textbook, suitable for students, researchers and engineers, gathers the experience of more than 20 years of teaching fracture mechanics, fatigue and corrosion to professional engineers and running experimental tests and verifications to solve practical problems in engineering applications. As such, it is a comprehensive blend of fundamental knowledge and technical tools to address the issues of fatigue and corrosion. The book initiates with a systematic description of fatigue from a phenomenological point of view, since the early signs of submicroscopic damage in few surface grains and continues describing, step by step, how these precursors develop to become mechanically small cracks and, eventually, macrocracks whose growth is governed by fracture mechanics. But fracture mechanics is also introduced to analyze stress corrosion and corrosion assisted fatigue in a rather advanced fashion. The author dedicates a particular attention to corrosion starting with an electrochemical treatment that mechanical e...

  16. Spectral caustics in laser assisted Breit-Wheeler process

    Science.gov (United States)

    Nousch, T.; Seipt, D.; Kämpfer, B.; Titov, A. I.

    2016-04-01

    Electron-positron pair production by the Breit-Wheeler process embedded in a strong laser pulse is analyzed. The transverse momentum spectrum displays prominent peaks which are interpreted as caustics, the positions of which are accessible by the stationary phases. Examples are given for the superposition of an XFEL beam with an optical high-intensity laser beam. Such a configuration is available, e.g., at LCLS at present and at European XFEL in near future. It requires a counter propagating probe photon beam with high energy which can be generated by synchronized inverse Compton backscattering.

  17. Spectral caustics in laser assisted Breit-Wheeler process

    CERN Document Server

    Nousch, T; Kämpfer, B; Titov, A I

    2015-01-01

    Electron-positron pair production by the Breit-Wheeler process embedded in a strong laser pulse is analyzed. The transverse momentum spectrum displays prominent peaks which are interpreted as caustics, the positions of which are accessible by the stationary phases. Examples are given for the superposition of an XFEL beam with an optical high-intensity laser beam. Such a configuration is available, e.g., at LCLS at present and at European XFEL in near future. It requires a counter propagating probe photon beam with high energy which can be generated by synchronized inverse Compton backscattering.

  18. Spectral caustics in laser assisted Breit–Wheeler process

    Directory of Open Access Journals (Sweden)

    T. Nousch

    2016-04-01

    Full Text Available Electron–positron pair production by the Breit–Wheeler process embedded in a strong laser pulse is analyzed. The transverse momentum spectrum displays prominent peaks which are interpreted as caustics, the positions of which are accessible by the stationary phases. Examples are given for the superposition of an XFEL beam with an optical high-intensity laser beam. Such a configuration is available, e.g., at LCLS at present and at European XFEL in near future. It requires a counter propagating probe photon beam with high energy which can be generated by synchronized inverse Compton backscattering.

  19. A comparison of the stress corrosion cracking susceptibility of commercially pure titanium grade 4 in Ringer's solution and in distilled water: a fracture mechanics approach.

    Science.gov (United States)

    Roach, Michael D; Williamson, R Scott; Thomas, Joseph A; Griggs, Jason A; Zardiackas, Lyle D

    2014-01-01

    From the results of laboratory investigations reported in the literature, it has been suggested that stress corrosion cracking (SCC) mechanisms may contribute to early failures in titanium alloys that have elevated oxygen concentrations. However, the susceptibility of titanium alloys to SCC in physiological environments remains unclear. In this study, a fracture mechanics approach was used to examine the SCC susceptibility of CP titanium grade 4 in Ringer's solution and distilled de-ionized (DI) water, at 37°C. The study duration was 26 weeks, simulating the non-union declaration of a plated fracture. Four wedge loads were used corresponding to 86-95% of the alloy's ligament yield load. The longest cracks were measured to be 0.18 mm and 0.10 mm in Ringer's solution and DI water, respectively. SEM analysis revealed no evidence of extensive fluting and quasi-cleavage fracture features which, in literature reports, were attributed to SCC. We thus postulate that the Ringer's solution accelerated the wedge-loaded crack growth without producing the critical stresses needed to change the fracture mechanism. Regression analysis of the crack length results led to a significant best-fit relationship between crack growth velocity (independent variable) and test electrolyte, initial wedge load, and time of immersion of specimen in electrolyte (dependent variables).

  20. Corrosion of High Chromium Ferritic/Martensitic Steels in High Temperature Water. a Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, P.; Lapena, J.; Blazquez, F. [Ciemat, Madrid (Spain)

    2000-07-01

    Available literature concerning corrosion of high-chromium ferritic/martensitic steels in high temperature water has been reviewed. The subjects considered are general corrosion, effect of irradiation on corrosion, stress corrosion cracking (SCC) and irradiation-assisted stress corrosion cracking (IASCC). In addition some investigations about radiation induced segregation (RIS) are shown in order to know the compositional changes at grain boundaries of these alloys and their influence on corrosion properties. The data on general corrosion indicate moderate corrosion rates in high temperature water up to 350 degree centigree. Considerably larger corrosion rates were observed under neutron irradiation. The works concerning to the behaviour of these alloys to stress corrosion cracking seem to conclude that in these materials is necessary to optimize the temper temperature and to carry out the post-weld heat treatments properly in order to avoid stress corrosion cracking. (Author) 40 refs.

  1. Caustic-based approach to understanding bunching dynamics and current spike formation in particle bunches

    Science.gov (United States)

    Charles, T. K.; Paganin, D. M.; Dowd, R. T.

    2016-10-01

    Current modulations, current spikes, and current horns, are observed in a range of accelerator physics applications including strong bunch compression in Free Electron Lasers and linear colliders, trains of microbunching for terahertz radiation, microbunching instability and many others. This paper considers the fundamental mechanism that drives intense current modulations in dispersive regions, beyond the common explanation of nonlinear and higher-order effects. Under certain conditions, neighboring electron trajectories merge to form caustics, and often result in characteristic current spikes. Caustic lines and surfaces are regions of maximum electron density, and are witnessed in accelerator physics as folds in phase space of accelerated bunches. We identify the caustic phenomenon resulting in cusplike current profiles and derive an expression which describes the conditions needed for particle-bunch caustic formation in dispersive regions. The caustic expression not only reveals the conditions necessary for caustics to form but also where in longitudinal space the caustics will form. Particle-tracking simulations are used to verify these findings. We discuss the broader implications of this work including how to utilize the caustic expression for manipulation of the longitudinal phase space to achieve a desired current profile shape.

  2. 16 CFR 1500.129 - Substances named in the Federal Caustic Poison Act.

    Science.gov (United States)

    2010-01-01

    ... Poison Act. 1500.129 Section 1500.129 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL... REGULATIONS § 1500.129 Substances named in the Federal Caustic Poison Act. The Commission finds that for those substances covered by the Federal Caustic Poison Act (44 Stat. 1406), the requirements of section 2(p)(1)...

  3. Biological treatment of sulfidic spent caustics under haloalkaline conditions using soda lake bacteria

    NARCIS (Netherlands)

    Graaff, de C.M.

    2012-01-01

    In this thesis, the development of a newbiotechnological process for the treatment of undiluted sulfidic spent caustics (SSC’s) using soda lake bacteria is described. SSC’s are waste solutions that are formed in the oil and gas industry due to the caustic (NaOH) scrubbing of hydrocarbon

  4. Corrosion and Maintenance Data Sharing (Partage des Donnees de Corrosion et de Maintenance)

    Science.gov (United States)

    2011-11-01

    when the environmental action is assisted by material wear under low vibratory relative motion of parts. The abrasion of the surface finishing, and...attention is given to some of the most dangerous forms of corrosion such as Stress Corrosion Cracking (SCC) and Exfoliation. On aluminium alloys, the...Effect of Environmental Species and Metallurgical Structure on the Hydrogen Entry into Steel” – Stress Corrosion Cracking and Hydrogen Embrittlement of

  5. Biases and caustics in long-range acoustic tomography

    Science.gov (United States)

    Munk, Walter; Wunsch, Carl

    1985-11-01

    We consider the travel time perturbation δt of acoustic rays in an ocean sound channel. The perturbations arom a straining e(x,z) of the water column. An expansion to second order gives δt ≈ τ + ατ , where and are suitably weighted strain wverages, α is a number of order 1 (except near caustics), and τ is the phase integral (the 'reduced travel time' in the seismic literature); τ is a function of ray steepness and range, and varies from zero for axial rays to order 10 s for steep rays at 1000 km range. The quadratic bais ατ changes sign at the caustics; generally it is negative (warm bias) for a range-dependent ocean as compared to a range-independent ocean with the same average properties. We consider two separate problems: (a) linear inversions for the range-averaged profile in soundspeed (temperature) introduces 0.5 m s -1 (0.1 °C) systematic errors arising from horizontal ocean variability (mesoscal activity), but these errors can be reduced by making corrections for . (b) In the problem of monitoring for climatic changes of large-scale ocean features, the quadratic bias is negligible compared to the sample variability, and there is an inherent advantage to the long-range horizontal integration in acoustic tomography over the traditional local measurements.

  6. A phenomenological study of initiation and propagation of stress corrosion cracks. Application to AISI 304L stainless steel in magnesium chloride; Etude phenomenologique de l`amorcage et de la propagation de fissures de corrosion sous contraintes. Application a l`acier inoxydable Z 2CN 18.10 dans le chlorure de magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Peyrat, C.; Raquet, O.; Helie, M.; Santarini, G. [CEA Fontenay-aux-Roses, 92 (France). Service de la Corrosion, d`Electrochimie et Chimie des Fluides

    1999-04-01

    A purely phenomenological study of Stress Corrosion Cracking (SCC) was performed using the couple AISI 304L austenitic stainless steel/boiling magnesium chloride aqueous solution. The exploitation of the morphological information (shape of the cracks and size distribution) available after constant elongation rate tests led to the apparent initiation of the cracks and to their growth rate. A law for the real initiation is proposed too and the elongation rate effect in quantitatively characterized. (authors) 8 refs.

  7. Part of the hydrogen in the intergranular crack by stress corrosion in primary circuit for the 600 and 690 nickel base alloys; Role de l'hydrogene dans le mecanisme de fissuration intergranulaire par corrosion sous contrainte en milieu primaire des alliages base nickel 600 et 690

    Energy Technology Data Exchange (ETDEWEB)

    Odemer, G.; Coudurier, A.; Jambon, F.; Chene, J. [CEA Saclay, Dept. de Physico-Chimie (DPC/SCCME/LECA), 91 - Gif sur Yvette (France); Odemer, G.; Coudurier, A.; Chene, J. [Evry Univ., UMR 8587 CNRS / CEA, LAMBE, 91 (France)

    2007-07-01

    The aim of this study is, in a first part, to characterize the hydrogen embrittlement sensitivity of the 600 and 690 based alloys in order to better understand the hydrogen role in the stress corrosion mechanism which appears in theses alloys in the primary circuit of the PWR type reactors. The authors studies how the hydrogen embrittlement is resulting from an interaction between the hydrogen and the plastic deformation. (A.L.B.)

  8. Dynamical observations on the crack tip zone and stress corrosion of two-dimensional MoS2

    Science.gov (United States)

    Ly, Thuc Hue; Zhao, Jiong; Cichocka, Magdalena Ola; Li, Lain-Jong; Lee, Young Hee

    2017-01-01

    Whether and how fracture mechanics needs to be modified for small length scales and in systems of reduced dimensionality remains an open debate. Here, employing in situ transmission electron microscopy, atomic structures and dislocation dynamics in the crack tip zone of a propagating crack in two-dimensional (2D) monolayer MoS2 membrane are observed, and atom-to-atom displacement mapping is obtained. The electron beam is used to initiate the crack; during in situ observation of crack propagation the electron beam effect is minimized. The observed high-frequency emission of dislocations is beyond previous understanding of the fracture of brittle MoS2. Strain analysis reveals dislocation emission to be closely associated with the crack propagation path in nanoscale. The critical crack tip plastic zone size of nearly perfect 2D MoS2 is between 2 and 5 nm, although it can grow to 10 nm under corrosive conditions such as ultraviolet light exposure, showing enhanced dislocation activity via defect generation.

  9. Dynamical observations on the crack tip zone and stress corrosion of two-dimensional MoS2

    KAUST Repository

    Ly, Thuc Hue

    2017-01-18

    Whether and how fracture mechanics needs to be modified for small length scales and in systems of reduced dimensionality remains an open debate. Here, employing in situ transmission electron microscopy, atomic structures and dislocation dynamics in the crack tip zone of a propagating crack in two-dimensional (2D) monolayer MoS2 membrane are observed, and atom-to-atom displacement mapping is obtained. The electron beam is used to initiate the crack; during in situ observation of crack propagation the electron beam effect is minimized. The observed high-frequency emission of dislocations is beyond previous understanding of the fracture of brittle MoS2. Strain analysis reveals dislocation emission to be closely associated with the crack propagation path in nanoscale. The critical crack tip plastic zone size of nearly perfect 2D MoS2 is between 2 and 5 nm, although it can grow to 10 nm under corrosive conditions such as ultraviolet light exposure, showing enhanced dislocation activity via defect generation.

  10. Effect of corrosion on flexural bond strength

    Directory of Open Access Journals (Sweden)

    Akshatha Shetty

    2014-09-01

    Full Text Available Corrosion is one of the main causes affecting durability of structures. Corrosion effects on structures cannot be ignored and replaced. To understand the performance of structures there is a need to study the rate at which different corrosion levels occur. Hence the present investigation has been taken up to study the behaviour of NBS (National Bureau of Standard beam specimens made up of Ordinary Portland Cement (OPC and Portland Pozzolona Cement (PPC concrete matrix were subjected to accelerated corrosion for different corrosion levels of 2.5 % to 10 % at 2.5 % interval. Results are compared with those for control beam specimen. It is observed that bond stress value decreases with the increase in corrosion levels. Also corrosion leads to the decline of load carrying capacity.

  11. 焊接工艺对奥氏体不锈钢应力腐蚀行为的影响%Effect of Welding Procedure on Stress Corrosion of Austenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    赵尔冰; 张亦良; 陈鴒志

    2011-01-01

    It is difficult to release residual stress for welding of austenitic stainless steel, therefore, its chlorine stress corrosion always occurs in engineering. The stress corrosion testing was done on different welding procedures of three different materials (304, 316 L of China, and 304 of German). The welding procedure includes shielded metal arc welding and flux cored CO2 shielded are welding through air cooling and water cooling after welding. The base metal, starting point and ending point of welding arc were tested. The better procedure is obtained through 100 samples, and the stress-life relationship of stress corrosion in boiled MgCl2 of two types of materials are formulated. The conclusion is that life of stress corrosion of 316 L is 15 times of 304, life of the starting point is longer than the ending point of welding arc, life of the butt weld is longer than the fillet weld, and faster cooling after welding is efficient for life of stress corrosion.%针对氯离子环境中奥氏体不锈钢焊缝较高的焊接残余应力极易引发应力腐蚀开裂的普遍性工程难题,对国产304、316L、德国304钢3种材料的不同焊接工艺进行了系列应力腐蚀实验研究.焊接工艺包括手工焊条电弧焊及CO2保护药芯电弧焊、焊后空冷及浇水速冷,取样位置包括母材、焊缝起弧及收弧.通过100多个试样的应力腐蚀对比实验,研究了各种工艺之间的优劣,拟合了2种材料在沸腾氯化镁环境中应力一寿命的数学关系.结果表明,对应力腐蚀寿命而言,316L是304钢的15倍以上、焊接起弧点高于收弧点、对接焊缝高于角焊缝;焊后速冷工艺可提高焊接接头抗应力腐蚀能力.

  12. EFFECTS OF STRUCTURE AND INTERNAL STRESSES IN OXIDE FILMS ON CORROSION MECHANISM OF NEW ZIRCONIUM ALLOY%氧化膜结构及内应力对新锆合金腐蚀机理的影响

    Institute of Scientific and Technical Information of China (English)

    章海霞; 李中奎; 周廉; 许并社; 王永祯

    2014-01-01

    The corrosion resistance of new zirconium alloys containing Nb,used as the fuel cladding materials in water-cooled nuclear power reactors,is closely related to the characteristics of the oxide films,including the internal stresses and the crystal structure.However,the relation of the corrosion kinetics to the internal stresses and the crystal structure of the oxide films has not been well understood,also the corrosion mechanism of new zirconium alloys has not been confirmed.Therefore,it is helpful to solve the above problems,furthermore improve the corrosion resistance of new zirconium alloys,to characterize the internal stresses and the crystal structure of the oxide films accurately.The internal stresses and the crystal structure of the oxide films of NZ2 zirconium alloy,corroded in 360 ℃,18.6 MPa lithiated water and 400 ℃,10.3 MPa steam,were tested by XRD and Raman spectroscopy,and the microstructure of the oxide films was investigated by SEM.The results of the crystal structure show that tetragonal ZrO2 (t-ZrO2) content in the oxide films of NZ2 alloy decreases,monoclinic ZrO2 (m-ZrO2) content increases with the prolongation of the corrosion time,t-ZrO2 transforms into m-ZrO2.And cubic ZrO2 (c-ZrO2) appears in the oxide films when the thickness of the oxide films reaches 2 μm.Corrosion resistance of NZ2 alloy is improved when the content of t-ZrO2 in the oxide films increases.The results of the internal stresses and the microstructure of the oxide films indicate that the high compressive stresses exist in the oxide films.At the beginning of the corrosion,the compressive stresses in the oxide films increase with the corrosion time.When the thickness of the oxide films reaches 2 μm,the compressive stresses exceed the critical value and the stresses are released.The stress relaxation leads to the formation of the cracks,which reduces the protection of the oxide films,therefore the corrosion transition occurs.After the transition,the compressive stresses of

  13. Stress corrosion cracking tests for low and high alloy steels in sour oilfield service. Tests performed at VTT

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, K. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity; Haemaelaeinen, E. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Engineering Materials

    1996-10-01

    The purpose of the studies was to validate the usefulness of the proposed NACE slow strain rate testing method and compare it with the EFC document. In the NACE document the testing takes place at a temperature of 177 deg C, the test solution contains 20 wt% NaCl, the partial pressure of H{sub 2}S varies between 14 and 28 bar and the partial pressure of CO{sub 2} between 14 and 55 bar. In the NACE document the strain rate is determined as 4 x 10{sup -6} 1/s and in the EFC document 1 x 10{sup -6} 1/s. The results showed brittle behaviour for the test material in all of the test environments, and in each case the elongation was less than 5%. For comparison purposes the SSRT was conducted with the test material also in an inert environment (N{sub 2} gas), where the fracture was ductile and elongation 65%. The tests conducted with different strain rates gave the same result, which shows that the difference between EFC and NACE documents within the strain rate is not significant in the environments studied. However, since the alloy 654 SMO, which is considered to have a high resistance to corrosion, failed the SSRT test in the environments determined in the NACE document, the NACE document can be considered too severe for testing of austenitic stainless steels. Since contrary to the NACE document the EFC document does not determine levels for hydrogen sulphide and carbon dioxide, the EFC document can be considered more suitable than the NACE document for testing of austenitic stainless steels for sour service. (author)

  14. Standard test method for evaluating stress-corrosion cracking of stainless alloys with different nickel content in boiling acidified sodium chloride solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method describes a procedure for conducting stress-corrosion cracking tests in an acidified boiling sodium chloride solution. This test method is performed in 25% (by mass ) sodium chloride acidified to pH 1.5 with phosphoric acid. This test method is concerned primarily with the test solution and glassware, although a specific style of U-bend test specimen is suggested. 1.2 This test method is designed to provide better correlation with chemical process industry experience for stainless steels than the more severe boiling magnesium chloride test of Practice G36. Some stainless steels which have provided satisfactory service in many environments readily crack in Practice G36, but have not cracked during interlaboratory testing using this sodium chloride test method. 1.3 This boiling sodium chloride test method was used in an interlaboratory test program to evaluate wrought stainless steels, including duplex (ferrite-austenite) stainless and an alloy with up to about 33% nickel. It may also b...

  15. The role of Hydrogen and Creep in Intergranular Stress Corrosion Cracking of Alloy 600 and Alloy 690 in PWR Primary Water Environments ? a Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Hua, F H

    2004-07-12

    Intergranular attack (IGA) and intergranular stress corrosion cracking (IGSCC) of Alloy 600 in PWR steam generator environment has been extensively studied for over 30 years without rendering a clear understanding of the essential mechanisms. The lack of understanding of the IGSCC mechanism is due to a complex interaction of numerous variables such as microstructure, thermomechanical processing, strain rate, water chemistry and electrochemical potential. Hydrogen plays an important role in all these variables. The complexity, however, significantly hinders a clearer and more fundamental understanding of the mechanism of hydrogen in enhancing intergranular cracking via whatever mechanism. In this work, an attempt is made to review the role of hydrogen based on the current understanding of grain boundary structure and chemistry and intergranular fracture of nickel alloys, effect of hydrogen on electrochemical behavior of Alloy 600 and Alloy 690 (e.g. the passive film stability, polarization behavior and open-circuit potential) and effect of hydrogen on PWSCC behavior of Alloy 600 and Alloy 690. Mechanistic studies on the PWSCC are briefly reviewed. It is concluded that further studies on the role of hydrogen on intergranular cracking in both inert and primary side environments are needed. These studies should focus on the correlation of the results obtained at different laboratories by different methods on materials with different metallurgical and chemical parameters.

  16. Evaluation of Stress Corrosion Cracking Susceptibility Using Fracture Mechanics Techniques, Part 1. [environmental tests of aluminum alloys, stainless steels, and titanium alloys

    Science.gov (United States)

    Sprowls, D. O.; Shumaker, M. B.; Walsh, J. D.; Coursen, J. W.

    1973-01-01

    Stress corrosion cracking (SSC) tests were performed on 13 aluminum alloys, 13 precipitation hardening stainless steels, and two titanium 6Al-4V alloy forgings to compare fracture mechanics techniques with the conventional smooth specimen procedures. Commercially fabricated plate and rolled or forged bars 2 to 2.5-in. thick were tested. Exposures were conducted outdoors in a seacoast atmosphere and in an inland industrial atmosphere to relate the accelerated tests with service type environments. With the fracture mechanics technique tests were made chiefly on bolt loaded fatigue precracked compact tension specimens of the type used for plane-strain fracture toughness tests. Additional tests of the aluminum alloy were performed on ring loaded compact tension specimens and on bolt loaded double cantilever beams. For the smooth specimen procedure 0.125-in. dia. tensile specimens were loaded axially in constant deformation type frames. For both aluminum and steel alloys comparative SCC growth rates obtained from tests of precracked specimens provide an additional useful characterization of the SCC behavior of an alloy.

  17. Corrosion in airframes

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  18. CORROSION IN AIRFRAMES

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  19. Investigation of the Use of Laser Shock Peening for Enhancing Fatigue and Stress Corrosion Cracking Resistance of Nuclear Energy Materials

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Vijay K. [Univ. of Cincinnati, OH (United States); Jackson, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Teysseyre, Sebastien [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alexandreanu, Bogdan [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Yiren [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-03-07

    The objective of this project, which includes close collaboration with scientists from INL and ANL, is to investigate and demonstrate the use of advanced mechanical surface treatments like laser shock peening (LSP) and ultrasonic nanocrystal surface modification (UNSM) and establish baseline parameters for enhancing the fatigue properties and SCC resistance of nuclear materials like nickel-based alloy 600 and 304 stainless steel. The research program includes the following key elements/tasks: 1) Procurement of Alloy 600 and 304 SS, heat treatment studies; 2) LSP and UNSM processing of base metal and welds/HAZ of alloys 600 and 304; (3) measurement and mapping of surface and sub-surface residual strains/stresses and microstructural changes as a function of process parameters using novel methods; (4) determination of thermal relaxation of residual stresses (macro and micro) and microstructure evolution with time at high temperatures typical of service conditions and modeling of the kinetics of relaxation; (5) evaluation of the effects of residual stress, near surface microstructure and temperature on SCC and fatigue resistance and associated microstructural mechanisms; and (6) studies of the effects of bulk and surface grain boundary engineering on improvements in the SCC resistance and associated microstructural and cracking mechanisms

  20. Testing the Caustic Ring Dark Matter Halo Model Against Observations in the Milky Way

    Science.gov (United States)

    Dumas, Julie; Newberg, Heidi Jo; Niedzielski, Bethany; Susser, Adam; Thompson, Jeffery M.; Weiss, Jake; Lewis, Kim M.

    2016-06-01

    One prediction of axion dark matter models is they can form Bose-Einstein condensates and rigid caustic rings as a halo collapses in the non-linear regime. In this thesis, we undertake the first study of a caustic ring model for the Milky Way halo (Duffy & Sikivie 2008), paying particular attention to observational consequences. We first present the formalism for calculating the gravitational acceleration of a caustic ring halo. The caustic ring dark matter theory reproduces a roughly logarithmic halo, with large perturbations near the rings. We show that this halo can reasonably match the known Galactic rotation curve. We are not able to confirm or rule out an association between the positions of the caustic rings and oscillations in the observed rotation curve, due to insufficient rotation curve data. We explore the effects of dark matter caustic rings on dwarf galaxy tidal disruption with N-body simulations. Simulations of the Sagittarius (Sgr) dwarf galaxy in a caustic ring halo potential, with disk and bulge parameters that are tuned to match the Galactic rotation curve, match observations of the Sgr trailing tidal tails as far as 90 kpc from the Galactic center. Like the Navarro-Frenk-White (NFW) halo, they are, however, unable to match the leading tidal tail. None of the caustic, NFW, or triaxial logarithmic halos are able to simultaneously match observations of the leading and trailing arms of the Sagittarius stream. We further show that simulations of dwarf galaxies that move through caustic rings are qualitatively similar to those moving in a logarithmic halo. This research was funded by NSF grant AST 10-09670, the NASA-NY Space Grant, and the American Fellowship from AAUW.

  1. Epidemiology and prevention of caustic ingestion in children

    DEFF Research Database (Denmark)

    Christesen, H B

    1994-01-01

    A total of 102 children less than 16 years of age admitted for caustic ingestion in the period 1976-1991 were registered. The annual incidence rate of hospitalization was 10.8:100,000 for the city of Aarhus, Denmark. Esophageal burns occurred with a frequency of 5.0:100,000 per year. Ninety......-four percent of the children were less than 5 years old. For this age group, the incidence rates of admission and esophageal burns were 34.6:100,000 and 15.8:100,000, respectively. All ingestions were accidental. The incidence rates of esophageal burns in children 0-4 years old (p = 0.019) decreased...

  2. Studying the microlenses mass function from statistical analysis of the caustic concentration

    Energy Technology Data Exchange (ETDEWEB)

    Mediavilla, T; Ariza, O [Departamento de Estadistica e Investigacion Operativa, Universidad de Cadiz, Avda de Ramon Puyol, s/n 11202 Algeciras (Spain); Mediavilla, E [Instituto de Astrofisica de Canarias, Avda Via Lactea s/n, La Laguna (Spain); Munoz, J A, E-mail: teresa.mediavilla@ca.uca.es, E-mail: octavio.ariza@uca.es, E-mail: emg@iac.es [Departamento de Astrofisica y Astronomia, Universidad de Valencia, Burjassot, Valencia (Spain)

    2011-09-22

    The statistical distribution of caustic crossings by the images of a lensed quasar depends on the properties of the distribution of microlenses in the lens galaxy. We use a procedure based in Inverse Polygon Mapping to easily identify the critical and caustic curves generated by a distribution of stars in the lens galaxy. We analyze the statistical distributions of the number of caustic crossings by a pixel size source for several projected mass densities and different mass distributions. We compare the results of simulations with theoretical binomial distributions. Finally we apply this method to the study of the stellar mass distribution in the lens galaxy of QSO 2237+0305.

  3. The Corrosion and Corrosion Fatigue Behavior of Nickel Based Alloy Weld Overlay and Coextruded Claddings

    Science.gov (United States)

    Stockdale, Andrew

    The use of low NOx boilers in coal fired power plants has resulted in sulfidizing corrosive conditions within the boilers and a reduction in the service lifetime of the waterwall tubes. As a solution to this problem, Ni-based weld overlays are used to provide the necessary corrosion resistance however; they are susceptible to corrosion fatigue. There are several metallurgical factors which give rise to corrosion fatigue that are associated with the localized melting and solidification of the weld overlay process. Coextruded coatings offer the potential for improved corrosion fatigue resistance since coextrusion is a solid state coating process. The corrosion and corrosion fatigue behavior of alloy 622 weld overlays and coextruded claddings was investigated using a Gleeble thermo-mechanical simulator retrofitted with a retort. The experiments were conducted at a constant temperature of 600°C using a simulated combustion gas of N2-10%CO-5%CO2-0.12%H 2S. An alternating stress profile was used with a minimum tensile stress of 0 MPa and a maximum tensile stress of 300 MPa (ten minute fatigue cycles). The results have demonstrated that the Gleeble can be used to successfully simulate the known corrosion fatigue cracking mechanism of Ni-based weld overlays in service. Multilayer corrosion scales developed on each of the claddings that consisted of inner and outer corrosion layers. The scales formed by the outward diffusion of cations and the inward diffusion of sulfur and oxygen anions. The corrosion fatigue behavior was influenced by the surface finish and the crack interactions. The initiation of a large number of corrosion fatigue cracks was not necessarily detrimental to the corrosion fatigue resistance. Finally, the as-received coextruded cladding exhibited the best corrosion fatigue resistance.

  4. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  5. TEM characterisation of stress corrosion cracks in nickel based alloys: effect of chromium content and chemistry of environment; Caracterisation par MET de fissures de corrosion sous contrainte d'alliages a base de nickel: influence de la teneur en chrome et de la chimie du milieu

    Energy Technology Data Exchange (ETDEWEB)

    Delabrouille, F

    2004-11-15

    Stress corrosion cracking (SCC) is a damaging mode of alloys used in pressurized water reactors, particularly of nickel based alloys constituting the vapour generator tubes. Cracks appear on both primary and secondary sides of the tubes, and more frequently in locations where the environment is not well defined. SCC sensitivity of nickel based alloys depends of their chromium content, which lead to the replacement of alloy 600 (15 % Cr) by alloy 690 (30 % Cr) but this phenomenon is not yet very well understood. The goal of this thesis is two fold: i) observe the effect of chromium content on corrosion and ii) characterize the effect of environment on the damaging process of GV tubes. For this purpose, one industrial tube and several synthetic alloys - with controlled chromium content - have been studied. Various characterisation techniques were used to study the corrosion products on the surface and within the SCC cracks: SIMS; TEM - FEG: thin foil preparation, HAADF, EELS, EDX. The effect of chromium content and surface preparation on the generalised corrosion was evidenced for synthetic alloys. Moreover, we observed the penetration of oxygen along triple junctions of grain boundaries few micrometers under the free surface. SCC tests show the positive effect of chromium for contents varying from 5 to 30 % wt. Plastic deformation induces a modification of the structure, and thus of the protective character, of the internal chromium rich oxide layer. SCC cracks which developed in different chemical environments were characterised by TEM. The oxides which are formed within the cracks are different from what is observed on the free surface, which reveals a modification of medium and electrochemical conditions in the crack. Finally we were able to evidence some structural characteristics of the corrosion products (in the cracks and on the surface) which turn to be a signature of the chemical environment. (author)

  6. Corrosion behaviour of non-ferrous metals in sea water

    Energy Technology Data Exchange (ETDEWEB)

    Birn, Jerzy; Skalski, Igor [Ship Design and Research Centre, Al. Rzeczypospolitej 8, 80-369 Gdansk (Poland)

    2004-07-01

    The most typical kinds of corrosion of brasses are selective corrosion (dezincification) and stress corrosion. Prevention against these kinds of corrosion lies in application of arsenic alloy addition and appropriate heat treatment removing internal stresses as well as in maintaining the arsenic and phosphorus contents on a proper level. The most typical corrosion of cupronickels is the local corrosion. Selective corrosion occurs less often and corrosion cracking caused by stress corrosion in sea water does not usually occur. Crevice corrosion is found especially in places of an heterogeneous oxidation of the surface under inorganic deposits or under bio-film. Common corrosive phenomena for brasses and cupronickels are the effects caused by sea water flow and most often the impingement attack. Alloy additions improve resistance to the action of intensive sea water flow but situation in this field requires further improvement, especially if the cheaper kinds of alloys are concerned. Contaminants of sea water such as ammonia and hydrogen sulphide are also the cause of common corrosion processes for all copper alloys. Corrosion of copper alloys may be caused also by sulphate reducing bacteria (SRB). Galvanic corrosion caused by a contact with titanium alloys e.g. in plate heat exchangers may cause corrosion of both kinds copper alloys. Bronzes belong to copper alloys of the highest corrosion resistance. Failures that sometimes occur are caused most often by the cavitation erosion, by an incorrect chemical composition of alloys or at last by their inadequate structure. The main problems of aluminium alloys service in sea water are following phenomena: local corrosion (pitting and crevice corrosion), galvanic corrosion, exfoliation and corrosion in the presence of OH- ions. The cause of local corrosion are caused by presence of passive film on the alloy's surface and presence of chlorides in sea water which are able to damage the passive film. Galvanic corrosion is

  7. Corrosion Fatigue in District Heating Water Tanks

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel

    1996-01-01

    Three candidate materials for construction of buffer tanks for district heating water have been tested for corrosion fatigue properties in a district heating water environment. The investigation included Slow Strain Rate Testing of plain tensile specimens, crack initiation testing by corrosion...... fatigue of plain tensile specimens and crack growth rate determination for Compact Tensile Specimens under corrosion fatigue conditions. The three materials are equal with respect to stress corrosion sensibility and crack initiation. Crack growth rate is increased with a factor of 4-6 relative to an inert...

  8. Improvement of stress corrosion cracking (SCC) resistance by cyclic pre-straining of 316L austenitic stainless steel in an aqueous boiling MgCl{sub 2} solution; Amelioration de la tenue a la corrosion sous contrainte (CSC) de l'acier inoxydable austenitique 316L en solution bouillante de MgCl{sub 2} par application d'une predeformation cyclique

    Energy Technology Data Exchange (ETDEWEB)

    Curiere, I. de; Bayle, B.; Magnin, Th. [Ecole Nationale Superieure des Mines, URA CNRS 1884, 42 - Saint-Etienne (France)

    2000-07-01

    Improving the materials resistance to stress corrosion cracking (SCC) has become a topic of wide interest for theoretical, engineering and financial reasons. The aim of this paper is to propose a process to delay the SCC damage. Recent studies of 316L austenitic stainless steel in boiling MgCl{sub 2} solutions show an improvement in SCC resistance by cyclic pre-straining in low cycle fatigue. This improvement consists of an increase in both strain to failure and crack initiation strain, during Slow Rate Tensile (SSRT) tests in aqueous solution. This paper analyses the effect of pre-fatigue in 316L on its mechanical and electrochemical responses to better understand the delay of SCC damage in boiling MgCl{sub 2}. The explanation for this beneficial effect is related to a modification of both surface electrochemical reactions kinetics and corrosion/plasticity interactions at the crack tip, due to the particular dislocation structure. (authors)

  9. Underground pipeline corrosion

    CERN Document Server

    Orazem, Mark

    2014-01-01

    Underground pipelines transporting liquid petroleum products and natural gas are critical components of civil infrastructure, making corrosion prevention an essential part of asset-protection strategy. Underground Pipeline Corrosion provides a basic understanding of the problems associated with corrosion detection and mitigation, and of the state of the art in corrosion prevention. The topics covered in part one include: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, n

  10. Caustics, pseudocaustics and the related illuminated and dark regions with the computational method of quantifier elimination

    Science.gov (United States)

    Ioakimidis, Nikolaos I.

    2017-01-01

    The method of caustics is a powerful experimental method in elasticity and particularly in fracture mechanics for crack problems. The related method of pseudocaustics is also of interest. Here we apply the computational method of quantifier elimination implemented in the computer algebra system Mathematica in order to determine (i) the non-parametric equation and two properties of the caustic at a crack tip and especially (ii) the illuminated and the dark regions related to caustics and pseudocaustics in plane elasticity and plate problems. The present computations concern: (i) The derivation of the non-parametric equation of the classical caustic about a crack tip through the elimination of the parameter involved (here the polar angle) as well as two geometrical properties of this caustic. (ii) The derivation of the inequalities defining the illuminated region on the screen in the problem of an elastic half-plane loaded normally by a concentrated load with the boundary of this illuminated region related to some extent to the caustic formed. (iii) Similarly for the problem of a clamped circular plate under a uniform loading with respect to the caustic and the pseudocaustic formed. (iv) Analogously for the problem of an equilateral triangular plate loaded by uniformly distributed moments along its whole boundary, which defines the related pseudocaustic. (v) The determination of quantities of interest in mechanics from the obtained caustics or pseudocaustics. The kind of computations in the applications (ii) to (iv), i.e. the derivation of inequalities defining the illuminated region on the screen, seems to be completely new independently of the use here of the method of quantifier elimination. Additional applications are also possible, but some of them require the expansion of the present somewhat limited power of the quantifier elimination algorithms in Mathematica. This is expected to take place in the future.

  11. Primary Water Stress Corrosion Cracks in Nickel Alloy Dissimilar Metal Welds: Detection and Sizing Using Established and Emerging Nondestructive Examination Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Braatz, Brett G.; Cumblidge, Stephen E.; Doctor, Steven R.; Prokofiev, Iouri

    2012-12-31

    The U.S. Nuclear Regulatory Commission has established the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT) as a follow-on to the international cooperative Program for the Inspection of Nickel Alloy Components (PINC). The goal of PINC was to evaluate the capabilities of various nondestructive evaluation (NDE) techniques to detect and characterize surface-breaking primary water stress corrosion cracks in dissimilar-metal welds (DMW) in bottom-mounted instrumentation (BMI) penetrations and small-bore (≈400-mm diameter) piping components. A series of international blind round-robin tests were conducted by commercial and university inspection teams. Results from these tests showed that a combination of conventional and phased-array ultrasound techniques provided the highest performance for flaw detection and depth sizing in dissimilar metal piping welds. The effective detection of flaws in BMIs by eddy current and ultrasound shows that it may be possible to reliably inspect these components in the field. The goal of PARENT is to continue the work begun in PINC and apply the lessons learned to a series of open and blind international round-robin tests that will be conducted on a new set of piping components including large-bore (≈900-mm diameter) DMWs, small-bore DMWs, and BMIs. Open round-robin testing will engage universities and industry worldwide to investigate the reliability of emerging NDE techniques to detect and accurately size flaws having a wide range of lengths, depths, orientations, and locations. Blind round-robin testing will invite testing organizations worldwide, whose inspectors and procedures are certified by the standards for the nuclear industry in their respective countries, to investigate the ability of established NDE techniques to detect and size flaws whose characteristics range from easy to very difficult to detect and size. This paper presents highlights of PINC and reports on the plans and progress for

  12. The corrosion and corrosion mechanical properties evaluation for the LBB concept in VVERs

    Energy Technology Data Exchange (ETDEWEB)

    Ruscak, M.; Chvatal, P.; Karnik, D.

    1997-04-01

    One of the conditions required for Leak Before Break application is the verification that the influence of corrosion environment on the material of the component can be neglected. Both the general corrosion and/or the initiation and, growth of corrosion-mechanical cracks must not cause the degradation. The primary piping in the VVER nuclear power plant is made from austenitic steels (VVER 440) and low alloy steels protected with the austenitic cladding (VVER 1000). Inspection of the base metal and heterogeneous weldments from the VVER 440 showed that the crack growth rates are below 10 m/s if a low oxygen level is kept in the primary environment. No intergranular cracking was observed in low and high oxygen water after any type of testing, with constant or periodic loading. In the framework of the LBB assessment of the VVER 1000, the corrosion and corrosion mechanical properties were also evaluated. The corrosion and corrosion mechanical testing was oriented predominantly to three types of tests: stress corrosion cracking tests corrosion fatigue tests evaluation of the resistance against corrosion damage. In this paper, the methods used for these tests are described and the materials are compared from the point of view of response on static and periodic mechanical stress on the low alloyed steel 10GN2WA and weld metal exposed in the primary circuit environment. The slow strain rate tests and static loading of both C-rings and CT specimens were performed in order to assess the stress corrosion cracking characteristics. Cyclic loading of CT specimens was done to evaluate the kinetics of the crack growth under periodical loading. Results are shown to illustrate the approaches used. The data obtained were evaluated also from the point of view of comparison of the influence of different structure on the stress corrosion cracking appearance. The results obtained for the base metal and weld metal of the piping are presented here.

  13. Structured caustic vector vortex optical field: manipulating optical angular momentum flux and polarization rotation.

    Science.gov (United States)

    Chen, Rui-Pin; Chen, Zhaozhong; Chew, Khian-Hooi; Li, Pei-Gang; Yu, Zhongliang; Ding, Jianping; He, Sailing

    2015-05-29

    A caustic vector vortex optical field is experimentally generated and demonstrated by a caustic-based approach. The desired caustic with arbitrary acceleration trajectories, as well as the structured states of polarization (SoP) and vortex orders located in different positions in the field cross-section, is generated by imposing the corresponding spatial phase function in a vector vortex optical field. Our study reveals that different spin and orbital angular momentum flux distributions (including opposite directions) in different positions in the cross-section of a caustic vector vortex optical field can be dynamically managed during propagation by intentionally choosing the initial polarization and vortex topological charges, as a result of the modulation of the caustic phase. We find that the SoP in the field cross-section rotates during propagation due to the existence of the vortex. The unique structured feature of the caustic vector vortex optical field opens the possibility of multi-manipulation of optical angular momentum fluxes and SoP, leading to more complex manipulation of the optical field scenarios. Thus this approach further expands the functionality of an optical system.

  14. TO THE QUESTION ABOUT THE INFLUENCE OF THE STRESSES IN THE ELEMENTS OF THE REINFORCEMENT SHAFTS AT THE RATE OF CORROSION

    Directory of Open Access Journals (Sweden)

    V. V. Kovalenko

    2008-03-01

    Full Text Available On the basis of laboratory explorations the features of conducting the corrosive process in the shaft reinforcement parts under the load from lifting buckets and rock mass were determined.

  15. Pattern recognition model to estimate intergranular stress corrosion cracking (IGSCC) at crevices and pit sites of 304 SS in BWR environments

    Energy Technology Data Exchange (ETDEWEB)

    Urquidi-Macdonald, Mirna [Penn State University, 212 Earth-Engineering Science Building, University Park, PA 16801 (United States)

    2004-07-01

    Many publications have shown that crack growth rates (CGR) due to intergranular stress corrosion cracking (IGSCC) of metals is dependent on many parameters related to the manufacturing process of the steel and the environment to which the steel is exposed. Those parameters include, but are not restricted to, the concentration of chloride, fluoride, nitrates, and sulfates, pH, fluid velocity, electrochemical potential (ECP), electrolyte conductivity, stress and sensitization applied to the steel during its production and use. It is not well established how combinations of each of these parameters impact the CGR. Many different models and beliefs have been published, resulting in predictions that sometimes disagree with experimental observations. To some extent, the models are the closest to the nature of IGSCC, however, there is not a model that fully describes the entire range of observations, due to the difficulty of the problem. Among the models, the Fracture Environment Model, developed by Macdonald et al., is the most physico-chemical model, accounting for experimental observations in a wide range of environments or ECPs. In this work, we collected experimental data on BWR environments and designed a data mining pattern recognition model to learn from that data. The model was used to generate CGR estimations as a function of ECP on a BWR environment. The results of the predictive model were compared to the Fracture Environment Model predictions. The results from those two models are very close to the experimental observations of the area corresponding to creep and IGSCC controlled by diffusion. At more negative ECPs than the potential corresponding to creep, the pattern recognition predicts an increase of CGR with decreasing ECP, while the Fracture Environment Model predicts the opposite. The results of this comparison confirm that the pattern recognition model covers 3 phenomena: hydrogen embrittlement at very negative ECP, creep at intermediate ECP, and IGSCC

  16. Corrosion studies in brines of the Salton Sea Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Carter, J.P.; McCawley, F.X.; Cramer, S.D.; Needham, P.B. Jr.

    1979-01-01

    Toward the goal of maximizing minerals and metals recovery from domestic resources, the Bureau of Mines, U.S. Department of the Interior, has conducted in situ corrosion studies at the Salton Sea Known Geothermal Resources Area (KGRA) in the Imperial Valley, Calif., to evaluate and characterize materials of construction for geothermal resources recovery plants. General-, pitting, and crevice-corrosion characteristics of 13 commercially available alloys were investigated for periods of 15 and 30 days in seven process environments expected to be found in typical geothermal resources plants. Stainless steel alloy 29-4, Inconel 625, and the Hastelloys G, S, and C-276 were the most resistant to general corrosion, did not pit, and exhibited little susceptibility to crevice corrosion. Stainless steel alloys 430, E-Brite 26-1, and 6X had low general corrosion rates, but pitted and were susceptible to crevice corrosion. Stainless steel alloy 316 L had a low corrosion rate, but corroded intergranularly, pitted, and was susceptible to crevice corrosion and to stress-corrosion cracking. Titanium--1.5 nickel and TiCode-12 had low corrosion rates, did not pit, and were not susceptible to crevice corrosion. Carbon and 4130 steels had high corrosion rates, pitted, and had high susceptibilities to crevice corrosion. The major scale-forming mineral on the corrosion samples in most of the process environments studied was galena mixed with lesser amounts of other minerals.

  17. Hot-wall corrosion testing of simulated high level nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, G.T.; Zapp, P.E.; Mickalonis, J.I.

    1995-01-01

    Three materials of construction for steam tubes used in the evaporation of high level radioactive waste were tested under heat flux conditions, referred to as hot-wall tests. The materials were type 304L stainless steel alloy C276, and alloy G3. Non-radioactive acidic and alkaline salt solutions containing halides and mercury simulated different high level waste solutions stored or processed at the United States Department of Energy`s Savannah River Site. Alloy C276 was also tested for corrosion susceptibility under steady-state conditions. The nickel-based alloys C276 and G3 exhibited excellent corrosion resistance under the conditions studied. Alloy C276 was not susceptible to localized corrosion and had a corrosion rate of 0.01 mpy (0.25 {mu}m/y) when exposed to acidic waste sludge and precipitate slurry at a hot-wall temperature of 150{degrees}C. Type 304L was susceptible to localized corrosion under the same conditions. Alloy G3 had a corrosion rate of 0.1 mpy (2.5 {mu}m/y) when exposed to caustic high level waste evaporator solution at a hot-wall temperature of 220{degrees}C compared to 1.1 mpy (28.0 {mu}/y) for type 304L. Under extreme caustic conditions (45 weight percent sodium hydroxide) G3 had a corrosion rate of 0.1 mpy (2.5 {mu}m/y) at a hot-wall temperature of 180{degrees}C while type 304L had a high corrosion rate of 69.4 mpy (1.8 mm/y).

  18. Cl-浓度对超级13Cr油管钢应力腐蚀开裂行为的影响%Effects of Cl- Concentration on Stress Corrosion Cracking Behaviors of Super 13Cr Tubing Steels

    Institute of Scientific and Technical Information of China (English)

    姚小飞; 谢发勤; 吴向清; 王毅飞

    2012-01-01

    Effects of Cl concentration on the stress corrosion cracking behaviors of super 13Cr tubing steels were investigated in different concentration of NaCl solution, that tensile strength, elongation rate, cracking time, stress corrosion cracking susceptibility (kscc) and fracture morphology were analyzed by the experimental method of slow strain rate tension (SSRT) stress corrosion cracking (SCO, δε curves, scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS) and X-ray diffraction (XRD). The results showed that the degree of stress corrosion was light at below 15% NaCl solution and was severe at the concentration above 25% NaCl solution. With Cl- concentration of solution increased, super 13Cr tubing steels mechanics properties reduced, SCC resistance properties reduced, the tendency of stress corrosion cracking increased, the stress corrosion cracking susceptibility kδ and kε both increased, and the increased tendency of kε were more obviously than kδ, effects of Cl- concentration on the plastic deformation of super 13Cr tubing steels were more significantly than tensile strength.%采用慢应变速率拉伸(SSRT)应力腐蚀开裂(SCC)的实验方法,通过应力应变(σ-ε)曲线、扫描电镜( SEM)、能谱分析(EDS)和X射线衍射分析(XRD)等手段分析了超级13Cr油管钢在NaCl溶液中的抗拉强度、延伸率、断裂时间、应力腐蚀开裂敏感性指数(kscc)和断口形貌,研究了Cl-浓度对其应力腐蚀开裂行为的影响.结果显示:当NaCl溶液浓度低于15%时,超级13Cr油管钢应力腐蚀的程度较轻,抗应力腐蚀开裂性能较好;而当NaCl溶液浓度大于25%时,其应力腐蚀的程度严重,抗应力腐蚀开裂性能较差;随溶液Cl-浓度的增大,超级13Cr油管钢的力学性能降低、抗SCC性能降低、应力腐蚀开裂的倾向增大、应力腐蚀开裂敏感性指数kσ和kε均呈现增大的趋势,且kε比kσ增大的趋势更明显;Cl浓度对超级13

  19. Corrosion Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Corrosion Testing Facility is part of the Army Corrosion Office (ACO). It is a fully functional atmospheric exposure site, called the Corrosion Instrumented Test...

  20. Wavefields Near Transverse Cusp Caustics Produced by Reflecting Ultrasonic Transients and Tone Bursts from Curved Surfaces.

    Science.gov (United States)

    Frederickson, Carl King

    Ultrasonic wavefields reflected from curved surfaces were studied in the vicinity of caustics. Acoustical and optical transverse cusp diffraction catastrophes produced by reflections from a curved metal surface in water were imaged by displaying the amplitude or intensity in an observation plane transverse to the general direction of propagation. The optical image was used to locate the cusp point in the observation plane. Acoustical diffraction patterns for sine waves, described by the Pearcey function, were calculated with the parameters determined by the experimental setup leaving no adjustable scaling parameters. The calculated and experimental acoustical diffraction patterns showed good agreement near the cusp point. The acoustical diffraction pattern showed the expected mirror symmetry about an axis. The pattern was shown to scale properly with frequency. The transverse cusp caustic separates space into a region with three rays and a region with one ray. Inside the caustic there are three rays, on the curve two of the rays merge and disappear leaving one ray outside. Transient signals reflected from curved surfaces exhibited the merging and disappearance of rays on the caustic. Relative arrival times for signals in calculated and recorded time traces agree well. The relation to the wavefront parameters of the temporal orientation of the travel time surface is discussed. The general shape of the travel time surface is that of the swallow tail caustic surface. The temporal shape of the transient echoes was seen to be generally that of the incident signal or of its Hilbert transform. The Hilbert transform shape identifies the signals that have touched the caustic. The observed arrival sequence of the transient signals was shh inside the caustic and one h outside, where s stands for a signal with the general shape of the incident signal and h for its Hilbert transform. The relation between the surface and wavefront parameters and the arrival sequence is given.

  1. Understanding the corrosion phenomena to organize the nondestructive evaluation programs in the nuclear power plants; Connaitre les phenomenes de corrosion pour organiser les programmes d'end dans les centrales nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Berge, J.Ph. [Federation Europeenne de Corrosion, 75 - Paris (France); Samman, J. [Electricite de France (EDF), Div. du Production Nucleaire, 75 - Paris (France)

    2001-07-01

    The french nuclear power plants used PWR which components revealed many corrosion defects of different shapes as stress corrosion cracks or pits. Understanding the corrosion processes will help the inspection of in service power plants. The following examples describe some corrosion cases and present the corresponding developed control methods: corrosion on condenser, secondary circuit pipes and corrosion-erosion, steam generator pipes, vessels head penetration. (A.L.B.)

  2. Materials characterization center workshop on corrosion of engineered barriers

    Energy Technology Data Exchange (ETDEWEB)

    Merz, M.D.; Zima, G.E.; Jones, R.H.; Westerman, R.E.

    1981-03-01

    A workshop on corrosion test procedures for materials to be used as barriers in nuclear waste repositories was conducted August 19 and 20, 1980, at the Battelle Seattle Research Center. The purpose of the meeting was to obtain guidance for the Materials Characterization Center in preparing test procedures to be approved by the Materials Review Board. The workshop identified test procedures that address failure modes of uniform corrosion, pitting and crevice corrosion, stress corrosion, and hydrogen effects that can cause delayed failures. The principal areas that will require further consideration beyond current engineering practices involve the analyses of pitting, crevice corrosion, and stress corrosion, especially with respect to quantitative predictions of the lifetime of barriers. Special techniques involving accelerated corrosion testing for uniform attack will require development.

  3. A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-05-11

    Titanium alloy degradation modes are reviewed in relation to their performance in repository environments. General corrosion, localized corrosion, stress corrosion cracking, hydrogen induced cracking, microbially influenced corrosion, and radiation-assisted corrosion of Ti alloys are considered. With respect to the Ti Grade 7 drip shields selected for emplacement in the repository at Yucca Mountain, general corrosion, hydrogen induced cracking, and radiation-assisted corrosion will not lead to failure within the 10,000 year regulatory period; stress corrosion cracking (in the absence of disruptive events) is of no consequence to barrier performance; and localized corrosion and microbially influenced corrosion are not expected to occur. To facilitate the discussion, Ti Grades 2, 5, 7, 9, 11, 12, 16, 17, 18, and 24 are included in this review.

  4. Corrosion behavior of corrosion resistant alloys in stimulation acids

    Energy Technology Data Exchange (ETDEWEB)

    Cheldi, Tiziana [ENI E and P Division, 20097 San Donato Milanese Milano (Italy); Piccolo, Eugenio Lo; Scoppio, Lucrezia [Centro Sviluppo Materiali, via Castel Romano 100, 00128 Rome (Italy)

    2004-07-01

    In the oil and gas industry, selection of CRAs for downhole tubulars is generally based on resistance to corrosive species in the production environment containing CO{sub 2}, H{sub 2}S, chloride and in some case elemental sulphur. However, there are non-production environments to which these materials must also be resistant for either short term or prolonged duration; these environments include stimulation acids, brine and completion fluids. This paper reports the main results of a laboratory study performed to evaluate the corrosion and stress corrosion behaviour to the acidizing treatments of the most used CRAs for production tubing and casing. Laboratory tests were performed to simulate both 'active' and 'spent' acids operative phases, selecting various environmental conditions. The selected steel pipes were a low alloyed steel, martensitic, super-martensitic, duplex 22 Cr, superduplex 25 Cr and super-austenitic stainless steels (25 Cr 35 Ni). Results obtained in the 'active' acid environments over the temperature range of 100-140 deg. C, showed that the blend acids with HCl at high concentration and HCl + HF represented too much severe conditions, where preventing high general corrosion and heavy localised corrosion by inhibition package becomes very difficult, especially for duplex steel pipe, where, in some case, the specimens were completely dissolved into the solution. On the contrary, all steels pipes were successfully protected by inhibitor when organic acid solution (HCOOH + CH{sub 3}COOH) were used. Furthermore, different effectiveness on corrosion protection was showed by the tested inhibitors packages: e.g. in the 90% HCl at 12% + 10 CH{sub 3}COOH acid blend. In 'spent' acid environments, all steel pipes showed to be less susceptible to the localised and general corrosion attack. Moreover, no Sulphide Stress Corrosion Cracking (SSC) was observed. Only one super-austenitic stainless steel U-bend specimen showed

  5. Faraday caustics: Singularities in the Faraday spectrum and their utility as probes of magnetic field properties

    CERN Document Server

    Bell, M R; Enßlin, T A

    2011-01-01

    We describe singularities in the distribution of polarized intensity as a function of Faraday depth (i.e. the Faraday spectrum) that arise due to line of sight (LOS) magnetic field reversals. We call these features Faraday caustics due to their similarity to optical caustics. They appear sharply spiked in the Faraday spectrum with a tail that extends to one side. The direction in which the tail extends depends on the way in which the LOS magnetic field reversal occurs (either changing from oncoming to retreating or vice versa). We describe how surfaces of Faraday caustics relate to boundaries between regions where the LOS magnetic field has opposite polarity. Examples from simulations of the polarized synchrotron emission from the Milky Way are provided. We derive the probability or luminosity distribution of Faraday caustics produced in a Gaussian magnetic field distribution as a function of their strength, F, and find that for strong Faraday caustics P(F) ~ F^(-3). If fully resolved, this distribution is al...

  6. Study on Resistance Against Stress Corrosion off Chlorine Ions of Cooling Water Stainless Steel Heat Exchangers%循环水不锈钢换热器抗氯离子应力腐蚀研究

    Institute of Scientific and Technical Information of China (English)

    董绍平

    2012-01-01

    炼油、化工装置中换热器占总设备数量的40%左右,占总投资的30%-45%,换热设备中大约有1/3是水冷器,其中不锈钢换热器容易受循环冷却水中Cl-影响而发生应力腐蚀,这就制约着有污水回用的循环水系统提升浓缩倍数。通过调研得出这种腐蚀受Cl-的含量、温度影响较大,pH值也有一定的影响。文章提出了当温度为50-80℃及pH值大于8时,工业循环水的Cl一质量浓度最大可达1000mg/L。还介绍了列管式和盘管式换热器的应力腐蚀开裂情况,并依据对现场调研结果得出换热器易发生应力腐蚀的部位主要包括胀接部位、U形管的弯曲部位、折流挡板和换热管其它部位等。并建议在循环水系统内进行挂片试验进一步研究不同因素和换热器不同部位对应力腐蚀的影响,以便提出防护措施。%The heat exchangers in petroleum refineries and chemical plants account to about 40% of the total equipment quantity and 30% -45% of total equipment investment. In heat exchange equipment, one third is water cooler. The stainless steel heat exchangers are subject to stress corrosion caused by C1 - in cooling water, which will limit the increase of concentration of cooling water system. The investigation study confirms that the C1- content and temperate have a greater impact on the corrosion and pH value also has a certain influence. At a temperature of 50 - 80 ~C and pH value of 8, the maximum mass concentration of C1 - in industry cooling water can be as high as 1000 mg/L. The stress corrosion cracking (SCC) of tube heat exchangers and coil heat exchangers is introduced. The field investigation has found that the locations which are subject to stress corrosion in heat exchanger are mainly expanded connections, bent of U tube, rod baffles, heat exchanger tubes, etc. It is suggested to have coupon testing in cooling water system to further study the impact of different factors

  7. Corrosion effects on friction factors

    Energy Technology Data Exchange (ETDEWEB)

    Magleby, H.L.; Shaffer, S.J.

    1996-03-01

    This paper presents the results of NRC-sponsored material specimen tests that were performed to determine if corrosion increases the friction factors of sliding surfaces of motor-operated gate valves, which could require higher forces to close and open safety-related valves when subjected to their design basis differential pressures. Friction tests were performed with uncorroded specimens and specimens subjected to accelerated corrosion. Preliminary tests at ambient conditions showed that corrosion increased the friction factors, indicating the need for additional tests duplicating valve operating parameters at hot conditions. The additional tests showed friction factors of corroded specimens were 0.1 to 0.2 higher than for uncorroded specimens, and that the friction factors of the corroded specimens were not very dependent on contact stress or corrosion film thickness. The measured values of friction factors for the three corrosion films tested (simulating three operating times) were in the range of 0.3 to 0.4. The friction factor for even the shortest simulated operating time was essentially the same as the others, indicating that the friction factors appear to reach a plateau and that the plateau is reached quickly.

  8. Caustic-Side Solvent Extraction Chemical and Physical Properties Progress in FY 2000 and FY 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, BA

    2002-04-17

    The purpose of this work was to provide chemical- and physical-property data addressing the technical risks of the Caustic-Side Solvent Extraction (CSSX) process as applied specifically to the removal of cesium from alkaline high-level salt waste stored at the US Department of Energy Savannah River Site. As part of the overall Salt Processing Project, this effort supported decision-making in regards to selecting a preferred technology among three alternatives: (1) CSSX, (2) nonelutable ion-exchange with an inorganic silicotitanate material and (3) precipitation with tetraphenylborate. High risks, innate to CSSX, that needed specific attention included: (1) chemical stability of the solvent matrix, (2) radiolytic stability of the solvent matrix, (3) proof-of-concept performance of the proposed process flowsheet with simulated waste, and (4) performance of the CSSX flowsheet with actual SRS high-level waste. This body of work directly addressed the chemical-stability risk and additionally provided supporting information that served to plan, carry out, and evaluate experiments conducted by other CSSX investigators addressing the other high risks. Information on cesium distribution in extraction, scrubbing, and stripping served as input for flowsheet design, provided a baseline for evaluating solvent performance under numerous stresses, and contributed to a broad understanding of the effects of expected process variables. In parallel, other measurements were directed toward learning how other system components distribute in the flowsheet. Such components include the solvent components themselves, constituents of the waste, and solvent-degradation products. Upon understanding which components influence flowsheet performance, it was then possible to address in a rational fashion how to clean up the solvent and maintain its stable function.

  9. New strategies for treatment and reuse of spent sulfidic caustic stream from petroleum industry

    Directory of Open Access Journals (Sweden)

    Jéssica Frontino Paulino

    2012-01-01

    Full Text Available This work examines traditional and new routes for removal of H2S and other sulfur compounds from spent sufidic caustic (SSC. SH- (hydrogenosulfide and S2- (sulfide ions were quantitatively oxidized at 25 ºC using H2O2, NaOCl or a spent sulfochromic mixture. SH-/S2- ions were also removed via reaction with freshly prepared iron or manganese hydroxides, or after passing the SSC through strong basic anion exchange resins (OH- form. The treated caustic solution, as well as iron/manganese hydroxides, removed H2S from diesel samples at 25 ºC. SSC treatment via strong basic anion-exchange resins produced the treated caustic solution with the highest free alkalinity.

  10. Study on Mechanism of Concrete Failure Induced by Steel Corrosion under Externally Applied Direct Current

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With the combination of electrochemical corrosion due to straycurrent in running tunnels of metro, the formula to determine the corrosion products of rebars in reinforced concrete subjected to externally applied direct current is proposed, and the influence of corrosion on stress in concrete is also discussed. Meanwhile, the concept of corrosion stress field and its mathematical formula are presented in the paper. Finally the failure mode of concrete and its shortest breaking time are also analyzed.

  11. Factors affecting the corrosivity of pulping liquors

    Science.gov (United States)

    Hazlewood, Patrick Evan

    Increased equipment failures and the resultant increase in unplanned downtime as the result of process optimization programs continue to plague pulp mills. The failures are a result of a lack of understanding of corrosion in the different pulping liquors, specifically the parameters responsible for its adjustment such as the role and identification of inorganic and organic species. The current work investigates the role of inorganic species, namely sodium hydroxide and sodium sulfide, on liquor corrosivity at a range of process conditions beyond those currently experienced in literature. The role of sulfur species, in the activation of corrosion and the ability of hydroxide to passivate carbon steel A516-Gr70, is evaluated with gravimetric and electrochemical methods. The impact of wood chip weathering on process corrosion was also evaluated. Results were used to identify black liquor components, depending on the wood species, which play a significant role in the activation and inhibition of corrosion for carbon steel A516-Gr70 process equipment. Further, the effect of black liquor oxidation on liquor corrosivity was evaluated. Corrosion and stress corrosion cracking performance of selected materials provided information on classes of materials that may be reliably used in aggressive pulping environments.

  12. Influence of the Environment on the General Corrosion Rate of Alloy 22 (N06022)

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Crook, P

    2004-04-19

    Nickel (Ni) can dissolve a large amount of alloying elements while still maintaining its desirable austenitic microstructure. The resulting alloys are generally divided in families depending on the type of alloying elements they contain. Each one of these families is aimed to specific applications. Corrosive environments in industrial applications are generally divided for example in reducing acids, oxidizing acids, contaminated acids, caustic environments, oxidizing salts, etc. Depending on the application and the environment (electrolyte composition and temperature) several or single alloys may be recommended to fabricate components. The Nichromium-molybdenum (Ni-Cr-Mo) series contains a balanced selection of beneficial alloying elements so it can handle a variety of aggressive environments. By design, Alloy 22 or N06022 is one of the most versatile corrosion resistant nickel alloys since it has an outstanding corrosion resistance both in reducing and oxidizing conditions.

  13. FEM Modelling of the Evolution of Corrosion Cracks in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Corrosion cracks are caused by the increasing volume of corrosion products during the corrosion of the reinforcement. After corrosion initiation the rust products from the corroded reinforcement will initially fill the porous zone near the reinforcement and the result in an expansion of the concr....... New results based on a Finite Element Analysis (FEM) are presented.......Corrosion cracks are caused by the increasing volume of corrosion products during the corrosion of the reinforcement. After corrosion initiation the rust products from the corroded reinforcement will initially fill the porous zone near the reinforcement and the result in an expansion...... of the concrete near the reinforcement. Tensile stresses are then initiated in the concrete. With increasing corrosion, the tensile stresses will at a certain time reach a critical value and cracks will be developed. The increase of the crack with after formation of the initial crack is the subject of this paper...

  14. Review of Artificial Neural Networks (ANN) applied to corrosion monitoring

    Science.gov (United States)

    Mabbutt, S.; Picton, P.; Shaw, P.; Black, S.

    2012-05-01

    The assessment of corrosion within an engineering system often forms an important aspect of condition monitoring but it is a parameter that is inherently difficult to measure and predict. The electrochemical nature of the corrosion process allows precise measurements to be made. Advances in instruments, techniques and software have resulted in devices that can gather data and perform various analysis routines that provide parameters to identify corrosion type and corrosion rate. Although corrosion rates are important they are only useful where general or uniform corrosion dominates. However, pitting, inter-granular corrosion and environmentally assisted cracking (stress corrosion) are examples of corrosion mechanisms that can be dangerous and virtually invisible to the naked eye. Electrochemical noise (EN) monitoring is a very useful technique for detecting these types of corrosion and it is the only non-invasive electrochemical corrosion monitoring technique commonly available. Modern instrumentation is extremely sensitive to changes in the system and new experimental configurations for gathering EN data have been proven. In this paper the identification of localised corrosion by different data analysis routines has been reviewed. In particular the application of Artificial Neural Network (ANN) analysis to corrosion data is of key interest. In most instances data needs to be used with conventional theory to obtain meaningful information and relies on expert interpretation. Recently work has been carried out using artificial neural networks to investigate various types of corrosion data in attempts to predict corrosion behaviour with some success. This work aims to extend this earlier work to identify reliable electrochemical indicators of localised corrosion onset and propagation stages.

  15. Superboom Caustic Analysis and Measurement Program (SCAMP) Final Report

    Science.gov (United States)

    Page, Juliet; Plotkin, Ken; Hobbs, Chris; Sparrow, Vic; Salamone, Joe; Cowart, Robbie; Elmer, Kevin; Welge, H. Robert; Ladd, John; Maglieri, Domenic; Piacsek, Andrew

    2015-01-01

    The objectives of the Superboom Caustic Analysis and Measurement (SCAMP) Program were to develop and validate, via flight-test measurements, analytical models for sonic boom signatures in and around focal zones as they are expected to occur during commercial aircraft transition from subsonic to supersonic flight, and to apply these models to focus boom prediction of low-boom aircraft designs. The SCAMP program has successfully investigated sonic boom focusing both analytically and experimentally, while gathering a comprehensive empirical flight test and acoustic dataset, and developing a suite of focused sonic boom prediction tools. An experimental flight and acoustic measurement test was designed during the initial year of the SCAMP program, with execution of the SCAMP flight test occurring in May 2011. The current SCAMP team, led by Wyle, includes partners from the Boeing Company, Pennsylvania State University, Gulfstream Aerospace, Eagle Aeronautics, and Central Washington University. Numerous collaborators have also participated by supporting the experiment with human and equipment resources at their own expense. The experiment involved precision flight of a McDonnell Douglas (now Boeing) F-18B executing different maneuvers that created focused sonic booms. The maneuvers were designed to center on the flight regime expected for commercial supersonic aircraft transonic transition, and also span a range of caustic curvatures in order to provide a variety of conditions for code validations. The SCAMP experiment was designed to capture concurrent F-18B on-board flight instrumentation data, high-fidelity ground-based and airborne acoustic data, and surface and upper air meteorological data. Close coordination with NASA Dryden resulted in the development of new experimental instrumentation and techniques to facilitate the SCAMP flight-test execution, including the development of an F-18B Mach rate cockpit display, TG-14 powered glider in-flight sonic boom measurement

  16. 正应力在波音737CL飞机龙骨梁剥蚀中的作用%Effect of Axial Stress on Exfoliation Corrosion of Keel Beam for Aircraft B737CL

    Institute of Scientific and Technical Information of China (English)

    黄昌龙; 万小朋

    2011-01-01

    根据波音737CL飞机龙骨梁ADF环形天线组件固定孔区域的剥蚀特征,采用有限元分析和盐雾环境暴露试验研究了正应力在剥蚀中的作用.结果表明,纵向L方向及长横向LT方向压应力可加速7150铝合金的剥蚀的形成和扩展;L方向、LT方向拉应力以及短横向ST方向压应力抑制合金的剥蚀的形成和扩展.%Based on an investigation of the exfoliation corrosion(EFC) evolution around ADF antenna installing holes on aluminum alloy 7150-T77511 keel beam for aircraft B737CL,the effect of axial stress on the EFC was studied by means of finite element analysis and corrosion test in salt fogging environment.The results showed that compressive stress along directions L and LT accelerated EFC,whilst tensile stress along directions L and LT,and compressive stress along direction ST retarded EFC.

  17. Iodine induced stress corrosion of zirconium and zircaloy-4 mechanisms. Translation to pellet cladding interaction conditions in PWR type reactors; Mecanismes de corrosion sous contrainte par l`iode dans le zirconium et le zircaloy-4. Transposition aux conditions d`interaction pastille-gaine dans les reacteurs a eau pressurisee

    Energy Technology Data Exchange (ETDEWEB)

    Fregonese, M

    1997-10-08

    This thesis is linked to the study of the Pellet-Cladding Interaction (PCI) phenomenon in Pressurized Water Reactors, which can lead to cladding rupture by iodine Stress Corrosion Cracking (SCC) of Zircaloy-4. Results are obtained through slow tensile tests performed in iodine methanol and in iodine vapour, on reference material, neutron irradiated material, and iodine zirconium implanted material. They allow to propose an explanation of the rapidity of the ruptures observed during PCI loadings, and to make the link between laboratory SCC tests and power ramp tests. Indeed, neutron irradiation facilitates the initiation and the transgranular propagation steps of the SCC cracks, due to strain localization and hardening associated to the presence of irradiation defects. On the other hand, recoiled iodine does not seem to affect SCC susceptibility of the material. On a chemical point of view, thermally released iodine is then responsible for PCI/SCC ruptures. A detailed calculation of iodine amount created by fission and released in the gap during irradiation makes it possible to show that local iodine concentration facing the pellet-to-pellet and the radial pellet cracks regions is sufficient for SCC cracks to develop in the metal. Finally, a competition between re-passivation and cracking is underscored. This results are in good agreement with the occurrence of an iodine adsorption mechanism. Adsorption could be assisted by a corrosion-deformation interaction phenomenon, and/or by the formation of solid and gaseous zirconium iodides. (author) 132 refs.

  18. Curvilinear wave-equation angle transform: Caustics, turning rays, absence of kinematic artifacts

    NARCIS (Netherlands)

    Stolk, C.C.; De Hoop, M.V.

    2007-01-01

    Migration of seismic reflection data to common image-point gathers is an integral part of both migration velocity analysis (MVA) and amplitude (AVA) analysis. Its applicability in complex geology depends on whether these gathers will be artifact free, and is related to the formation of caustics and

  19. Structural evaluation of mixer pump installed in Tank 241-AN-107 for caustic addition project

    Energy Technology Data Exchange (ETDEWEB)

    Leshikar, G.A.

    1995-06-16

    This report documents the structural analysis and evaluation of a mixer pump and caustic addition system to be used in Tank 107-AN. This pump will be installed in the central pump pit of this double- shell tank for the purpose of bringing the hydroxide ion concentration into compliance with Tank Farm operating specifications.

  20. Biological treatment of refinery spent caustics under halo-alkaline conditions

    NARCIS (Netherlands)

    Graaff, de M.; Bijmans, M.F.M.; Abbas, B.; Euverink, G.J.W.; Muyzer, G.; Janssen, A.J.H.

    2011-01-01

    The present research demonstrates the biological treatment of refinery sulfidic spent caustics in a continuously fed system under halo-alkaline conditions (i.e. pH 9.5; Na(+)= 0.8M). Experiments were performed in identical gas-lift bioreactors operated under aerobic conditions (80-90% saturation) at

  1. Prediction of complications following unintentional caustic ingestion in children. Is endoscopy always necessary?

    DEFF Research Database (Denmark)

    Christesen, H B

    1995-01-01

    The records of 115 children hospitalized following caustic ingestion over an 18.5-year period from 1976 to 1994 were reviewed. The relationship between types of product ingested, signs and symptoms, degree of esophageal injury and complications was analyzed. All complications were the result of s...

  2. Novel Electrochemical Treatment of Spent Caustic from the Hydrocarbon Industry Using Ti/BDD

    Directory of Open Access Journals (Sweden)

    Alejandro Medel

    2015-01-01

    Full Text Available During the crude oil refining process, NaOH solutions are used to remove H2S, H2Saq, and sulfur compounds from different hydrocarbon streams. The residues obtained are called “spent caustics.” These residues can be mixed with those obtained in other processes, adding to its chemical composition naphthenic acids and phenolic compounds, resulting in one of the most dangerous industrial residues. In this study, the use of electrochemical technology (ET, using BDD with Ti as substrate (Ti/BDD, is evaluated in electrolysis of spent caustic mixtures, obtained through individual samples from different refineries. In this way, the Ti/BDD’s capability of carrying out the electrochemical destruction of spent caustics in an acidic medium is evaluated having as key process a chemical pretreatment phase. The potential production of •OHs, as the main reactive oxygen species electrogenerated over Ti/BDD surface, was evaluated in HCl and H2SO4 through fluorescence spectroscopy, demonstrating the reaction medium’s influence on its production. The results show that the hydrocarbon industry spent caustics can be mineralized to CO2 and water, driving the use of ET and of the Ti/BDD to solve a real problem, whose potential and negative impact on the environment and on human health is and has been the environmental agencies’ main focus.

  3. Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Zhujie [Univ. of Michigan, Ann Arbor, MI (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States); Bartels, David [Univ. of Notre Dame, IN (United States)

    2015-04-02

    This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that the effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.

  4. Topical mitomycin C can effectively alleviate dysphagia in children with long-segment caustic esophageal strictures.

    Science.gov (United States)

    El-Asmar, K M; Hassan, M A; Abdelkader, H M; Hamza, A F

    2015-07-01

    Caustic ingestion in children and the resulting long esophageal strictures are usually difficult to be managed, and eventually, esophageal replacement was required for cases refractory to frequent dilatation sessions. Topical mitomycin C (MMC) application has been used recently to improve the results of endoscopic dilatation for short esophageal strictures. The study aims to assess the role of MMC application in management of long-segment caustic esophageal strictures. From January 2009 to June December 2013, patients presented with long caustic esophageal stricture (>3 cm in length) were included in this study and subjected to topical MMC application after endoscopic esophageal dilatation on multiple sessions. Regular follow-up and re-evaluation were done. A dysphagia score was used for close follow-up clinically; verification was done radiologically and endoscopically. During the specified follow-up period, 21 patients with long caustic esophageal stricture were subjected to topical MMC application sessions. Clinical, radiological, and endoscopic resolution of strictures occurred in 18 patients (85.7% cure rate). Number of dilatation sessions to achieve resolution of dysphagia was (n = 14.3 ± 5.7) with application of mitomycin two to six times. There was no recurrence in short- and mid-term follow-up. No complications were encountered related to topical MMC application. MMC is a promising agent in management of long-segment caustic esophageal strictures. Long-term follow-up is needed to prove its efficacy and to evaluate potential long-term side-effects of MMC application.

  5. Understanding the Risk of Chloride Induced Stress Corrosion Cracking of Interim Storage Containers for the Dry Storage of Spent Nuclear Fuel: Evolution of Brine Chemistry on the Container Surface.

    Energy Technology Data Exchange (ETDEWEB)

    Enos, David; Bryan, Charles R.

    2015-10-01

    Although the susceptibility of austenitic stainless steels to chloride-induced stress corrosion cracking is well known, uncertainties exist in terms of the environmental conditions that exist on the surface of the storage containers. While a diversity of salts is present in atmospheric aerosols, many of these are not stable when placed onto a heated surface. Given that the surface temperature of any container storing spent nuclear fuel will be well above ambient, it is likely that salts deposited on its surface may decompose or degas. To characterize this effect, relevant single and multi-salt mixtures are being evaluated as a function of temperature and relative humidity to establish the rates of degassing, as well as the likely final salt and brine chemistries that will remain on the canister surface.

  6. Assessment of copper resistance to stress-corrosion cracking in nitrite solutions by means of joint analysis of acoustic emission measurements, deformation diagrams, qualitative and quantitative fractography, and non-linear fracture mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Khanzhin, V.G.; Nikulin, S.A. [Moscow State Inst. of Steel and Alloys (Russian Federation)

    2005-06-01

    A study of stress-corrosion cracking (SCC) of copper in 0.1M NaNO{sub 2} aqueous solution is presented. The fracture kinetics was monitored by measuring the acoustic emission (AE) signals. Macro- and micro-fractography analysis, using scanning electron microscopy (SEM), was employed to investigate the fracture mechanisms. Estimates of stress intensity factor, KI, and J-integral were derived in order to assess the resistance of copper to stress corrosion cracking. Two kinds of SCC tests under continuous circulation of the corrosive solution were employed in the present study: 1. Constant extension rate (2x10{sup -6}/s) tests on pre-cracked, middle tension (MT) panel specimens. 2. Tests on pre-cracked, compact tension (CT) specimens at a fixed (by a fixing bolt) opening of the crack walls ({delta} = 0.3 mm, K{sub i} = 27 MPax{radical}m). The time base for these tests was about two months. After the completion of the SCC test, the CT specimen was additionally tested, under a constant-rate (0.02 mm/s) off-center extension. In the both kinds of tests, the SCC fracture kinetics is found to exhibit two typical stages: Stage 1: SCC initiation stage (after a certain incubation period, T{sub i}, measured to be T{sub i} {approx_equal} 3-4 hours for MT specimens under constant extension, the corresponding stress was {sigma} {approx_equal} 40-70 MPa, and T{sub i} {approx_equal} 200 hours for CT specimens under a fixed crack wall opening). Stage 2: Active fracture process (SCC macro-fracture) distinguished by strong AE pulses (which are registered after time T{sub 2} {approx_equal} 8 hours for MT specimens and T{sub 2} {approx_equal} 800 hours for CT specimens). Fractography analysis has shown that the zone of SCC fracture in MT specimens extends to approximately 1,500 {mu}m. A 400-700 {mu}m deep zone of brittle transgranular fracture, which included small areas showing characteristic SCC 'striations', was observed adjacent to the fatigue pre-crack area. At higher

  7. Rehabilitation of the gas pipeline that had a rupture in service caused by SCC (Stress Corrosion C raking); Rehabilitacion al servicio de un gasoducto que ha sufrido una ruptura en servicio por SCC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fernando; Carzoglio, Eduardo; Hryciuk, Pedro [TGN - Transportadora de Gas del Norte S.A. (Argentina). Depto. de Integridad

    2003-07-01

    TGN had a rupture in service on Gasoducto Troncal Norte. After initial evaluation of the causes of the rupture it was concluded that it had been caused by Stress Corrosion Cracking (SCC). Subsequent investigation in the area of the rupture revealed that colonies of cracks, typical of SCC were found in pipes located near the rupture. In order to put back in service the pipeline in a safety condition, SCC mitigation activities were performed. A decision was made to conduct a hydro test along approximately 30 kilometers of pipe. The stages of the works, the problems faced and the solutions found are dealt with, as well as the conclusions reached upon completion of the works which allowed a better understanding of SCC phenomenon. The methodology for the identification of those areas susceptible to SCC is also described. (author)

  8. Theoretical Analysis of Reinforcement Tunnel Lining Corrosion

    Directory of Open Access Journals (Sweden)

    ZhiQiang Zhangand

    2013-05-01

    Full Text Available The main cause of ageing damage in reinforced concrete structures is reinforcement corrosion. Damage can be detected visually as coincident cracks along the reinforcement bar, which are significant of both reduction of the re-bar, cross-section and loss of bond strength for reinforced concrete. The reinforced concrete is one of the most widely used engineering materials as final lining of tunnels. The corrosion is common durability problems that have significant effect on the tunnel performance. This study intends to analysis reinforcement concrete corrosion at the tunnel lining by applying temperature expansion theory on steel through numerical simulation process, with expansive force effect. The thickness of concrete cover and the diameter of steel bar have an impact on the stress for reinforcement concrete during propagation of corrosion process. The corrosion cracks appear at the corner of a tunnel lining then in invert and vault because the maximum stress will be in the corner then in invert and vault. The internal force in the concrete lining changes differently when the corrosion rate change.

  9. CO2 Corrosion and Grooving Corrosion Behavior of the ERW Joint of the Q125 Grade Tube Steel

    Institute of Scientific and Technical Information of China (English)

    Li-dong WANG; Feng-lei LIU; Qing-yun ZHAO; Hui-bin WU

    2015-01-01

    In order to investigate the CO2 corrosion behavior and the grooving corrosion susceptibility of electric resistance welded tubes of the Q125 grade, the high temperature and high pressure autoclave was employed to conduct CO2 corrosion experiments for the welded joint. The mechanisms of grooving corrosion and the factors inlfuencing grooving corrosion susceptibility were identiifed by electrochemical measurement, microstructure observation, residual stress examination, micro-region composition and orientation analysis. The CO2 corrosion results show that the corrosion resistance of the base material is the best, followed by heat-affected zone and the welded seam is the worst. The grooving corrosion occurred in the welded seam, and the grooving corrosion susceptibility of welded seam is relativity high. The dominated reason for the grooving corrosion of the electric resistance welded jointis the notable inclusions consisting of MnS as the main content in the welded seam.The proportion of high-angle grain bound-aries in the welding zone is higher than that of base metal and the heat affected zone, which plays an important role in the corrosion behavior of the welded seam.

  10. 低碳-低锰系油井套管用钢抗硫化氢应力腐蚀开裂性能%Hydrogen Sulfide Resistant Stress Corrosion Cracking of Low C-Mn Steels for Oil Well Casing

    Institute of Scientific and Technical Information of China (English)

    贺飞; 尚成嘉; 张峰; 毕宗岳

    2013-01-01

    对621 MPa(90ksi)级抗硫化氢腐蚀油井套管用钢的合金设计、热处理工艺以及组织和性能关系进行了研究,分别设计了0.08C-0.8Mn和0.20C-0.8Mn 2种低碳-低锰试验钢,并重点研究了经调质处理后试验钢的位错、析出物和碳化物对SSCC性能的影响.研究结果表明,采用低碳-低锰,结合Nb、V、Ti和B的微合金设计,通过适当的调质热处理工艺可以获得优良的力学性能、韧性和抗硫化氢应力腐蚀开裂性能,满足相关标准的要求.研究结果还表明,不共平面的位错群、细小的析出物以及弥散的高球化率碳化物,可以使钢具有很好的抗硫化氢应力腐蚀开裂性能.%Alloy design, heat treatment process and microstructure and properties relationship of 621 MPa(90ksi) grade oil well casing steels of H2S resistant corrosion were studied. Such two kinds as 0. 08C-0. 8Mn and 0. 20C-0. 8Mn of low C-Mn tested steels were designed, respectively. And the effect of dislocation, precipitation and carbide of tested steels after heat treatment on SSCC performance was investigated. The results show that the low C-Mn and Nb-V-Ti-B micro-alloy design has excellent mechanical properties, toughness and resistance to H2S stress corrosion cracking performance through proper quenching and tempering heat treatment process, to meet the requirements of the relevant standards. The results also show that the un-coplanar dislocation group, fine precipitates and dispersive high sphericity carbide would be beneficial to excellent hydrogen sulfide stress corrosion cracking resistance.

  11. Modelling of Corrosion Cracks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.......Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed....

  12. EFRT M-12 Issue Resolution: Caustic Leach Rate Constants from PEP and Laboratory-Scale Tests

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A.; Rassat, Scot D.; Eslinger, Paul W.; Aaberg, Rosanne L.; Aker, Pamela M.; Golovich, Elizabeth C.; Hanson, Brady D.; Hausmann, Tom S.; Huckaby, James L.; Kurath, Dean E.; Minette, Michael J.; Sundaram, S. K.; Yokuda, Satoru T.

    2009-08-14

    Testing Summary Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed and constructed and is to be operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes.” The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. The PEP also includes non-prototypic ancillary equipment to support the core processing. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP; vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to leach solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct injection of steam to accelerate the leaching process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP-1, the 19-M NaOH is added to un-concentrated waste slurry (3 to 8 wt% solids), while for leaching in UFP-2, the slurry is

  13. Direct Causticizing for Black Liquor Gasification in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Scott Sinquefield; Xiaoyan Zeng, Alan Ball

    2010-03-02

    Gasification of black liquor (BLG) has distinct advantages over direct combustion in Tomlinson recovery boilers. In this project we seek to resolve causticizing issues in order to make pressurized BLG even more efficient and cost-effective. One advantage of BLG is that the inherent partial separation of sulfur and sodium during gasification lends itself to the use of proven high yield variants to conventional kraft pulping which require just such a separation. Processes such as polysulfide, split sulfidity, ASAQ, and MSSAQ can increase pulp yield from 1% to 10% over conventional kraft but require varying degrees of sulfur/sodium separation, which requires additional [and costly] processing in a conventional Tomlinson recovery process. However during gasification, the sulfur is partitioned between the gas and smelt phases, while the sodium all leaves in the smelt; thus creating the opportunity to produce sulfur-rich and sulfur-lean white liquors for specialty pulping processes. A second major incentive of BLG is the production of a combustible product gas, rich in H2 and CO. This product gas (a.k.a. “syngas”) can be used in gas turbines for combined cycle power generation (which is twice as efficient as the steam cycle alone), or it can be used as a precursor to form liquid fuels, such as dimethyl ether or Fischer Tropsh diesel. There is drawback to BLG, which has the potential to become a third major incentive if this work is successful. The causticizing load is greater for gasification of black liquor than for combustion in a Tomlinson boiler. So implementing BLG in an existing mill would require costly increases to the causticizing capacity. In situ causticizing [within the gasifier] would handle the entire causticizing load and therefore eliminate the lime cycle entirely. Previous work by the author and others has shown that titanate direct causticizing (i.e. in situ) works quite well for high-temperature BLG (950°C), but was limited to pressures below

  14. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Møller, Per

    Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management...... of reinforcement corrosion....

  15. Caustic Recycling Pilot Unit to Separate Sodium from LLW at Hanford Site - 12279

    Energy Technology Data Exchange (ETDEWEB)

    Pendleton, Justin; Bhavaraju, Sai; Priday, George; Desai, Aditya; Duffey, Kean; Balagopal, Shekar [Ceramatec Inc., Salt Lake City, UT 84119 (United States)

    2012-07-01

    As part of the Department of Energy (DOE) sponsored Advanced Remediation Technologies initiative, a scheme was developed to combine Continuous Sludge Leaching (CSL), Near-Tank Cesium Removal (NTCR), and Caustic Recycling Unit (CRU) using Ceramatec technology, into a single system known as the Pilot Near-Tank Treatment System (PNTTS). The Cesium (Cs) decontaminated effluent from the NTCR process will be sent to the caustic recycle process for recovery of the caustic which will be reused in another cycle of caustic leaching in the CSL process. Such an integrated mobile technology demonstration will give DOE the option to insert this process for sodium management at various sites in Hanford, and will minimize the addition of further sodium into the waste tanks. This allows for recycling of the caustic used to remove aluminum during sludge washing as a pretreatment step in the vitrification of radioactive waste which will decrease the Low Level Waste (LLW) volume by as much as 39%. The CRU pilot process was designed to recycle sodium in the form of pure sodium hydroxide. The basis for the design of the 1/4 scale pilot caustic recycling unit was to demonstrate the efficient operation of a larger scale system to recycle caustic from the NTCR effluent stream from the Parsons process. The CRU was designed to process 0.28 liter/minute of NTCR effluent, and generate 10 M concentration of 'usable' sodium hydroxide. The proposed process operates at 40 deg. C to provide additional aluminum solubility and then recover the sodium hydroxide to the point where the aluminum is saturated at 40 deg. C. A system was developed to safely separate and vent the gases generated during operation of the CRU with the production of 10 M sodium hydroxide. Caustic was produced at a rate between 1.9 to 9.3 kg/hr. The CRU was located inside an ISO container to allow for moving of the unit close to tank locations to process the LLW stream. Actual tests were conducted with the NTCR effluent

  16. Results Of Routine Strip Effluent Hold Tank, Decontaminated Salt Solution Hold Tank, Caustic Wash Tank And Caustic Storage Tank Samples From Modular Caustic-Side Solvent Extraction Unit During Macrobatch 6 Operations

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. B.

    2014-01-02

    Strip Effluent Hold Tank (SEHT), Decontaminated Salt Solution Hold Tank (DSSHT), Caustic Wash Tank (CWT) and Caustic Storage Tank (CST) samples from the Interim Salt Disposition Project (ISDP) Salt Batch (“Macrobatch”) 6 have been analyzed for 238Pu, 90Sr, 137Cs, and by Inductively Coupled Plasma Emission Spectroscopy (ICPES). The Pu, Sr, and Cs results from the current Macrobatch 6 samples are similar to those from comparable samples in previous Macrobatch 5. In addition the SEHT and DSSHT heel samples (i.e. ‘preliminary’) have been analyzed and reported to meet NGS Demonstration Plan requirements. From a bulk chemical point of view, the ICPES results do not vary considerably between this and the previous samples. The titanium results in the DSSHT samples continue to indicate the presence of Ti, when the feed material does not have detectable levels. This most likely indicates that leaching of Ti from MST has increased in ARP at the higher free hydroxide concentrations in the current feed.

  17. AZ31B镁合金TIG焊接件应力腐蚀性能研究%Research on the Properties of Stress Corrosion Cracking for Tungsten Inert-Gas Arc Welded AZ31B Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    葛茂忠; 项建云; 张永康

    2013-01-01

    为了研究AZ31B镁合金钨极氩弧焊接件应力腐蚀性能,室温下采用三点加载的方式,在去离子水中对试样进行应力腐蚀试验.利用光学显微镜(OM)观测试样微观结构,利用扫描电镜(SEM)观测应力腐蚀断口,利用X-350A型X射线应力仪和CHI660B型电化学工作站分别测定试样表面残余应力和动电位极化曲线.试验结果表明:采用单面焊双面成型工艺,在45~50 A的焊接电流及合适的焊接速度条件下,焊接2.2 mm厚AZ31B镁合金薄板时,钨极氩弧焊能够获得理想的焊接接头,抗拉强度达到209 MPa;焊接件热影响区表面残余拉应力为60 MPa;同母材相比,焊接件自腐蚀电位减小27 mV,腐蚀电流增大了41.4%,从而增加焊接件腐蚀倾向;AZ31B焊接件在去离子水中浸没192 h后出现应力腐蚀开裂,属于穿晶型脆性断裂,这表明AZ31B镁合金焊接件在去离子水中具有很高的应力腐蚀敏感性.%In order to study the properties of the stress corrosion cracking (SCO for the tungsten inert-gas (TIG) arc welded AZ31B magnesium alloy sheets, the SCC susceptibility of the welded samples was assessed by three points loading method in deionized water at room temperature. The microstructure of specimens and fracture surfaces were analyzed by OM and SEM, respectively. Surface residual stress and potentiodynamic polarization behaviors of the welded samples were examined by using X-ray diffraction technology and a CHI660B electrochemical workstation, respectively. The results show that when TIG arc welding was used to weld AZ31B Mg alloy plates with the thickness of 2. 2 mm by using single-side welding double-side molding process, the ideal welding joints can be obtained at the welding current range from 45 A to 50 A and appropriate welding speed, the ultimate tensile strength of the welded joints is 209 Mpa; The residual tensile stress is 60 Mpa in the surface of heat effected zone of the welded joints; corrosion potential

  18. Corrosion inhibitors; Los inhibidores de corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Godinez, L. A.; Meas, Y.; Ortega-Borges, R.; Corona, A.

    2003-07-01

    In this paper, we briefly describe the characteristics, cost and electrochemical nature of the corrosion phenomena as well as some of the technologies that are currently employed to minimize its effect. The main subject of the paper however, deals with the description, classification and mechanism of protection of the so-called corrosion inhibitors. Examples of the use of these substances in different aggressive environments are also presented as means to show that these compounds, or their combination, can in fact be used as excellent and relatively cheap technologies to control the corrosion of some metals. In the last part of the paper, the most commonly used techniques to evaluate the efficiency and performance of corrosion inhibitors are presented as well as some criteria to make a careful and proper selection of a corrosion inhibitor technology in a given situation. (Author) 151 refs.

  19. Electrochemical and pitting corrosion resistance of AISI 4145 steel subjected to massive laser shock peening treatment with different coverage layers

    Science.gov (United States)

    Lu, J. Z.; Han, B.; Cui, C. Y.; Li, C. J.; Luo, K. Y.

    2017-02-01

    The effects of massive laser shock peening (LSP) treatment with different coverage layers on residual stress, pitting morphologies in a standard corrosive solution and electrochemical corrosion resistance of AISI 4145 steel were investigated by pitting corrosion test, potentiodynamic polarisation test, and SEM observations. Results showed massive LSP treatment can effectively cause an obvious improvement of pitting corrosion resistance of AISI 4145 steel, and increased coverage layer can also gradually improve its corrosion resistance. Massive LSP treatment with multiple layers was shown to influence pitting corrosion behaviour in a standard corrosive solution.

  20. Galaxy And Mass Assembly: Estimating galaxy group masses via caustic analysis

    CERN Document Server

    Alpaslan, Mehmet; Driver, Simon; Norberg, Peder; Peacock, John A; Baldry, Ivan; Bland-Hawthorn, Joss; Brough, Sarah; Hopkins, Andrew M; Kelvin, Lee S; Liske, Jochen; Loveday, Jon; Merson, Alexander; Nichol, Robert C; Pimbblet, Kevin

    2012-01-01

    We have generated complementary halo mass estimates for all groups in the Galaxy And Mass Assembly Galaxy Group Catalogue (GAMA G3Cv1) using a modified caustic mass estimation algorithm, originally developed by Diaferio & Geller (1997). We calibrate the algorithm by applying it on a series of 9 GAMA mock galaxy light cones and investigate the effects of using different definitions for group centre and size. We select the set of parameters that provide median-unbiased mass estimates when tested on mocks, and generate mass estimates for the real group catalogue. We find that on average, the caustic mass estimates agree with dynamical mass estimates within a factor of 2 in 90.8 +/- 6.1% groups and compares equally well to velocity dispersion based mass estimates for both high and low multiplicity groups over the full range of masses probed by the G3Cv1.

  1. K-Area Acid/Caustic Basin groundwater monitoring report: First quarter 1992

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C.Y.

    1992-06-01

    During first quarter 1992, samples from the seven KAC monitoring wells at the K-Area Acid/Caustic Basin of Savannah River Plant were analyzed for herbicides, indicator parameters, major ions, pesticides, radionuclides, turbidity, volatile organic compounds, and other constituents. Monitoring results that exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) and the Savannah River Site (SRS) flagging criteria and turbidity standards during the quarter are discussed in this report. No constituent exceeded the PDWS in the KAC wells at the K-Area Acid/Caustic Basin during first quarter 1992. Total organic halogens exceeded the Flag 2 criterion in wells KAC 6, and 7, and iron exceeded the Flag 2 criterion in well KAC 6. Well KAC 2 was the only well in the KAC well series to exceed the SRS turbidity standard.

  2. K-Area Acid/Caustic Basin groundwater monitoring report. Second quarter 1994

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    During second quarter 1994, samples from the KAC-monitoring wells at the K-Area Acid/Caustic Basin were collected and analyzed for herbicides/pesticides, indicator parameters, metals, nitrate, radionuclide indicators, and other constituents. Monitoring results that exceeded the final Primary Drinking Water Standards (PDWS), other Savannah River Site (SRS) Flag 2 criteria, of the SRS turbidity standard are provided in this report. No constituents exceeded the final PDWS in the KAC wells. Aluminum, iron, and specific conductance exceeded other SRS flagging criteria in one or more of the downgradient wells. Total organic halogens was elevated in upgradient well KAC 3. Groundwater flow direction and rate in the water table beneath the K-Area Acid/Caustic Basin were similar to past quarters.

  3. Detecting stellar spots through polarimetry observations of microlensing events in caustic-crossing

    CERN Document Server

    Sajadian, Sedighe

    2015-01-01

    In this work, we investigate if gravitational microlensing can magnify the polarization signal of a stellar spot and make it be observable. A stellar spot on a source star of microlensing makes polarization signal through two channels of Zeeman effect and breaking circular symmetry of the source surface brightness due to its temperature contrast. We first explore the characteristics of perturbations in polarimetric microlensing during caustic-crossing of a binary lensing as follows: (a) The cooler spots over the Galactic bulge sources have the smaller contributions in the total flux, although they have stronger magnetic fields. (b) The maximum deviation in the polarimetry curve due to the spot happens when the spot is located near the source edge and the source spot is first entering the caustic whereas the maximum photometric deviation occurs for the spots located at the source center. (c) There is a (partial) degeneracy for indicating spot's size, its temperature contrast and its magnetic induction from the...

  4. Flow-induced corrosion behavior of absorbable magnesium-based stents.

    Science.gov (United States)

    Wang, Juan; Giridharan, Venkataraman; Shanov, Vesselin; Xu, Zhigang; Collins, Boyce; White, Leon; Jang, Yongseok; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2014-12-01

    The aim of this work was to study corrosion behavior of magnesium (Mg) alloys (MgZnCa plates and AZ31 stents) under varied fluid flow conditions representative of the vascular environment. Experiments revealed that fluid hydrodynamics, fluid flow velocity and shear stress play essential roles in the corrosion behavior of absorbable magnesium-based stent devices. Flow-induced shear stress (FISS) accelerates the overall corrosion (including localized, uniform, pitting and erosion corrosions) due to the increased mass transfer and mechanical force. FISS increased the average uniform corrosion rate, the localized corrosion coverage ratios and depths and the removal rate of corrosion products inside the corrosion pits. For MgZnCa plates, an increase of FISS results in an increased pitting factor but saturates at an FISS of ∼0.15Pa. For AZ31 stents, the volume loss ratio (31%) at 0.056Pa was nearly twice that (17%) at 0Pa before and after corrosion. Flow direction has a significant impact on corrosion behavior as more severe pitting and erosion corrosion was observed on the back ends of the MgZnCa plates, and the corrosion product layer facing the flow direction peeled off from the AZ31 stent struts. This study demonstrates that flow-induced corrosion needs be understood so that Mg-based stents in vascular environments can be effectively designed.

  5. 核电汽轮机转子结构应力腐蚀裂纹扩展研究%Study on Stress Corrosion Cracking Growth of Turbine Rotor in Power Plant

    Institute of Scientific and Technical Information of China (English)

    焦广臣; 王炜哲; 蒋浦宁; 刘应征

    2013-01-01

    建立二维轴对称转子模型,有限元计算转子结构的应力场和稳态温度场.以这些计算结果为基础,采用Clark裂纹扩展模型和Paris裂纹扩展模型分析在不同的裂纹尺寸下转子结构中某点的应力腐蚀裂纹扩展速率,比较两种模型在工程实际应用中的优劣.%The stress fields and steady temperature fields are obtained by calculating the rotor model of 2D axisymmetric model by using the finite element analysis ( FEA). Based on the numerical results, the stress corrosion crack ( SCC ) growths at a certain point of the model are calculated by using the Clark model and the Paris model, and the comparative analysis of the results of two crack growth model is made for advantage in practical application.

  6. SPHERICAL NONLINEAR PULSES FOR THE SOLUTIONS OF NONLINEAR WAVE EQUATIONS Ⅱ, NONLINEAR CAUSTIC

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This article discusses spherical pulse like solutions of the system of semilinear wave equations with the pulses focusing at a point and emerging outgoing in three space variables. In small initial data case, it shows that the nonlinearities have a strong effect at the focal point. Scattering operator is introduced to describe the caustic crossing. With the aid of the L∞ norms, it analyzes the relative errors in approximate solutions.

  7. Effects of Temperature on the Slow Strain Rate Tension Stress Corrosion Cracking of Super 13Cr Tubing Steel%温度对超级13Cr油管钢慢拉伸应力腐蚀开裂的影响

    Institute of Scientific and Technical Information of China (English)

    姚小飞; 谢发勤; 吴向清; 王毅飞

    2012-01-01

    Effects of temperature on the stress corrosion cracking of super 13Cr tubing steel were investigated in 3. 5% NaCl,that tensile strength and elongation and cracking time and stress corrosion cracking susceptibility index kscc and fracture morphology were analyzed by slow strain rate tensile stress corrosion cracking (SSRT) experiment method and σ-ε curve and SEM. The results shows that the degree of stress corrosion were lesser at below 60℃ and were severe at higher 80 ℃. With the rise of temperature, the super 13Cr tubing steel tensile strength decreased,e-longation rate decreased, contraction ratio decreases, breaking time was reduced, stress corrosion cracking tendency of increase, the stress corrosion cracking susceptibility index kσ and kε are increasing, and the increased trend of kε were obviously than kσ, effects of temperature on the plastic deformation of super 13Cr tubing steel were greater than the tensile strength.%采用慢应变速率拉伸(SSRT)应力腐蚀开裂试验方法,通过σ-ε曲线和SEM等分析了超级13Cr油管钢抗拉强度、延伸率、断裂时间、应力腐蚀开裂敏感性指数(kSCC)和断口形貌;研究了温度对其在3.5% NaCl溶液中应力腐蚀开裂(SCC)的影响.结果表明:当温度<60℃时应力腐蚀的程度较轻;当温度>80℃时应力腐蚀的程度严重;随温度的升高,超级13Cr油管钢的抗拉强度降低,延伸率减小,断面收缩率减小,断裂时间减小,应力腐蚀开裂的倾向性增大,应力腐蚀开裂敏感性指数kσ和kε均呈现增大的趋势,且kε比kσ增大的趋势更显著;温度对超级13Cr油管钢的塑性变形性的影响比对抗拉强度的影响更大.

  8. Prevention of corrosion in prestressing steels

    NARCIS (Netherlands)

    Polder, R.B.

    1996-01-01

    Corrosion of prestressing steel may lead to sudden, so called brittle failure, due to the special microstructure of the steel and the high tensile forces. Such brittle failure may seriously reduce the load capacity of a prestressed concrete structure. In principle all stressed high strength steel is

  9. Washing and caustic leaching of Hanford tank sludge: Results of FY 1997 studies

    Energy Technology Data Exchange (ETDEWEB)

    Lumetta, G.J.; Burgeson, I.E.; Wagner, M.J.; Liu, J.; Chen, Y.L.

    1997-08-01

    The current plan for remediating the Hanford tank farms consists of waste retrieval, pretreatment, treatment (immobilization), and disposal. The tank wastes will be partitioned into high-level and low-level fractions. The HLW will be immobilized in a borosilicate glass matrix; the resulting glass canisters will then be disposed of in a geologic repository. Because of the expected high cost of HLW vitrification and geologic disposal, pretreatment processes will be implemented to reduce the volume of immobilized high-level waste (IHLW). Caustic leaching (sometimes referred to as enhanced sludge washing or ESW) represents the baseline method for pretreating Hanford tank sludges. Caustic leaching is expected to remove a large fraction of the Al, which is present in large quantities in Hanford tank sludges. A significant portion of the P is also expected to be removed from the sludge by metathesis of water-insoluble metal phosphates to insoluble hydroxides and soluble Na{sub 3}PO{sub 4}. Similar metathesis reactions can occur for insoluble sulfate salts, allowing the removal of sulfate from the HLW stream. This report describes the sludge washing and caustic leaching tests performed at the Pacific Northwest National Laboratory in FY 1996. The sludges used in this study were taken from Hanford tanks AN-104, BY-108, S-101, and S-111.

  10. Caustic ingestion in adults: The role of endoscopic classification in predicting outcome

    Directory of Open Access Journals (Sweden)

    Tang Jui-Hsiang

    2008-07-01

    Full Text Available Abstract Background The ingestion of caustic substances induces an extensive spectrum of injuries to the aerodigestive tract which include extensive necrosis and perforation of the esophagus and stomach. The gold standard of safely assessing depth, extent of injury, and appropriate therapeutic regimen is esophagogastroduodenoscopy (EGD. The objective of this study was to report our clinical experience and to evaluate the role of a 6-point EGD classification system of injury in predicting outcomes in adult patients diagnosed with caustic agent ingestion. Methods The study was a retrospective medical chart review from 273 patients admitted to the Chang Gung Memorial Hospital in Tao-Yuan, Taiwan between June 1999 and July 2006 for treatment of caustic ingestion. The patients underwent EGD within 24 hours of admission and mucosal damage was graded using Zagar's modified endoscopic classification scheme. After treatment, patients were followed in the outpatient clinic for a minimum of 6 months. Results A total of 273 patients were included for analysis. Grade 3b injury was the most common caustic injury (n = 82, 30.03%, followed by grade 2b injuries (n = 62, 22.71%. Stricture was the most common complication (n = 66, 24.18%, followed by aspiration pneumonia (n = 31, 11.36%, and respiratory failure (n = 21, 7.69%. Compared to grade 3a mucosal injury, grade 3b mucosal injuries were at greater risk of prolonged hospital stay (odds ratio [OR]: 2.44; 95% confidence interval [CI]: 1.25–4.80, ICU admission (OR: 10.82; 95% CI: 2.05–200.39, and gastrointestinal (OR: 4.15; 95% CI: 1.55–13.29 and systemic complications (OR: 4.07; 95% CI: 1.81–14.07. Conclusion In patients with caustic ingestion, EGD should be performed within 12 to 24 hours and categorized according to a 6-point scale. Patients with grade 3b burns identified on endoscopy have high rates of morbidity. The 6-point scale is useful for predicting immediate and long-term complications, and

  11. Successful treatment of corrosive esophageal strictures after failed esophageal reconstructions with colon and jejunum

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jing-hai; JIANG Yao-guang; WANG Ru-wen; ZHAO Yun-ping; GONG Tai-qian; TAN Qun-you; MA Zheng; LIN Yi-dan; DENG Bo

    2006-01-01

    Dense and extensive esophageal strictures after caustic agent ingestion require surgical treatment. Colon, stomach and jejunum can be used to reconstruct esophagus. Here, we report an unusual patient with corrosive esophageal stricture who had received unsuccessful esophageal replacements twice at other hospitals. Colon interposition had been first performed 6 months after corrosive esophageal burn,but the colon graft necrosis occurred. Esophageal reconstruction had been carried out 10 years later in another hospital. However, the graft necrosis developed again 5 months later. A salvage operation was performed to remove the necrotic transplant in our hospital. Then as much food as possible had been given to expand the stomach through the gastrostomy since the procedure. The patient underwent esophagectomy and concomitant gastroesophagostomy in the neck 1.5 years later. Esophageal dilations had been performed to prevent recurrent anastomotic stricture for 1 year. He has eaten a normal diet since being discharged.

  12. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  13. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments...... and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  14. Mill Integration-Pulping, Stream Reforming and Direct Causticization for Black Liquor Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Adriaan van Heiningen

    2007-06-30

    MTCI/StoneChem developed a steam reforming, fluidized bed gasification technology for biomass. DOE supported the demonstration of this technology for gasification of spent wood pulping liquor (or 'black liquor') at Georgia-Pacific's Big Island, Virginia mill. The present pre-commercial R&D project addressed the opportunities as well as identified negative aspects when the MTCI/StoneChem gasification technology is integrated in a pulp mill production facility. The opportunities arise because black liquor gasification produces sulfur (as H{sub 2}S) and sodium (as Na{sub 2}CO{sub 3}) in separate streams which may be used beneficially for improved pulp yield and properties. The negative aspect of kraft black liquor gasification is that the amount of Na{sub 2}CO{sub 3} which must be converted to NaOH (the so called causticizing requirement) is increased. This arises because sulfur is released as Na{sub 2}S during conventional kraft black liquor recovery, while during gasification the sodium associated Na{sub 2}S is partly or fully converted to Na{sub 2}CO{sub 3}. The causticizing requirement can be eliminated by including a TiO{sub 2} based cyclic process called direct causticization. In this process black liquor is gasified in the presence of (low sodium content) titanates which convert Na{sub 2}CO{sub 3} to (high sodium content) titanates. NaOH is formed when contacting the latter titanates with water, thereby eliminating the causticizing requirement entirely. The leached and low sodium titanates are returned to the gasification process. The project team comprised the University of Maine (UM), North Carolina State University (NCSU) and MTCI/ThermoChem. NCSU and MTCI are subcontractors to UM. The principal organization for the contract is UM. NCSU investigated the techno-economics of using advanced pulping techniques which fully utilize the unique cooking liquors produced by steam reforming of black liquor (Task 1). UM studied the kinetics and

  15. Description of a disposition line on the stress corrosion cracking behaviour of ferritic reactor pressure vessel steels under BWR-conditions; Beschreibung einer einhuellenden Risswachstumskurve zum Spannungsrisskorrosionsverhalten von ferritischen Reaktordruckbehaelter (RDB)-Staehlen unter Siedewasserreaktor (SWR)-Bedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, G. [HEW, Hamburg (Germany); Hoffmann, H. [VGB-GS, Essen (Germany); Ilg, U. [EnBW Kraftwerke AG, Philippsburg (Germany); Wachter, O. [E.ON-Kernkraft, Hannover (Germany); Widera, M. [RWE Power, Essen (Germany); Roth, A. [Framatome ANP GmbH, Erlangen (Germany)

    2002-07-01

    The inner surface of the reactor pressure vessel of BWR reactors is lined with a welded, corrosion-resistant steel liner. In an assumed case of liner rupture down to the low-alloy ferritic base material, an integrity assessment of the pressure vesssel in consideration of the effects of reactor coolant is of utmost importance, and research in this field has been going on for more than ten years now. An analysis of the available data shows that it is now possible to describe a disposition line on the stress corrosion cracking behaviour of ferritic reactor pressure vessel steels in BWR conditions. Crack growth rates of a stress intensity factor corresponding to a T/4 wall defect (i.e. 25 percent of the wall thickness) are technically not relevant. This scientific finding is supported by measurements of about 450 reactor operation years of all German LWR reactor plants, none of which showed crack initiation in the reactor pressure vessel. [German] Die mediumberuehrte Innenoberflaeche des Reaktordruckbehaelters (RDB) von Siedewasserreaktoren (SWR) ist mit einer korrosionsbestaendigen austenitischen Schweissplattierung versehen. Fuer den unterstellten Fall einer bis auf den niedriglegierten, ferritischen Grundwerkstoff durchgerissenen Pattierung ist fuer die Beurteilung der Integritaet des RDB unter Beruecksichtigung der Einwirkung des Reaktorkuehlmittels die Klaerung der Frage eines korrosionsgestuetzten Risswachstums von grosser Bedeutung. Dieses Thema ist daher bereits seit mehr als 10 Jahren Gegenstand umfangreicher Forschungsaktivitaeten. Ende der 80er- und Anfang der 90er-Jahre wurden fuer ferritische RDB-Staehle von SWR-Anlagen Risswachstumsgeschwindigkeiten veroeffentlicht, die binnen weniger als einem Jahr zum Durchriss der drucktragenden Wand eines RDB gefuehrt haetten. Daraufhin wurden internationale Forschungsaktivitaeten zur Ermittlung zuverlaessiger und reproduzierbarer Risswachstumsdaten initiiert, deren Ergebnisse zusammenfassend dargestellt werden. Die

  16. Erosion-corrosion; Erosionkorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Aghili, B

    1999-05-01

    A literature study on erosion-corrosion of pipings in the nuclear industry was performed. Occurred incidents are reviewed, and the mechanism driving the erosion-corrosion is described. Factors that influence the effect in negative or positive direction are treated, as well as programs for control and inspection. Finally, examples of failures from databases on erosion-corrosion are given in an attachment 32 refs, 16 figs, tabs

  17. Electrochemical corrosion studies

    Science.gov (United States)

    Knockemus, W. W.

    1986-01-01

    The objective was to gain familiarity with the Model 350 Corrosion Measurement Console, to determine if metal protection by grease coatings can be measured by the polarization-resistance method, and to compare corrosion rates of 4130 steel coated with various greases. Results show that grease protection of steel may be determined electrochemically. Studies were also conducted to determine the effectiveness of certain corrosion inhibitors on aluminum and steel.

  18. D-410精制塔塔底封头筒体连接区域应力腐蚀力学原因分析%MECHANICAL ANALYSIS ON THE STRESS CORROSION IN THE CONNECTION ZONE OF THE SKIRT AND BOTTOM HEAD OF THE DISTILLATION TOWER

    Institute of Scientific and Technical Information of China (English)

    郭伟华; 杨树波; 张传鑫; 张卫义

    2012-01-01

    In this paper, the finite element stress analysis and strength evaluation are carried out for the D-410 distillation tower head and skirt bottom connected region to obtain the stress distribution law of this zone. The results from calculation and analysis indicate that there is a circumferential stress belt distributing along the circumference in this zone. The actual crack follows the axial direction , which is consistent with the stress state of stress corrosion. According to the conditions of the stress corrosion sensitivity, tower reactor materials containing sul-fide, Cl- and dissolved oxygen, it can be determined that the crack defects are caused by stress corrosion instead of strength failure.%对D-410精制塔塔底封头与筒体连接区域进行了详细的有限元应力分析和强度评定,得到了该区域应力分布规律.计算分析结果表明,这个区域存在一个沿整个圆周分布的周向拉应力带,实际裂纹均沿轴向方向,符合应力腐蚀应力状态,结合材料的应力腐蚀敏感性和塔底介质存在硫化物、Cl-和溶解氧等情况,可以确定裂纹缺陷是应力腐蚀,而不是强度破坏.

  19. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  20. Corrosion of an austenite and ferrite stainless steel weld

    Directory of Open Access Journals (Sweden)

    BRANIMIR N. GRGUR

    2011-07-01

    Full Text Available Dissimilar metal connections are prone to frequent failures. These failures are attributed to the difference in the mechanical properties across the weld, the coefficients of thermal expansion of the two types of steels and the resulting creep at the interface. For the weld analyzed in this research, it was shown that corrosion measurements can be used for a proper evaluation of the quality of weld material and for the prediction of whether or not the material, after the applied welding process, can be in service without failures. It was found that the corrosion of the weld analyzed in this research resulted from the simultaneous activity of different types of corrosion. In this study, electrochemical techniques including polarization and metallographic analysis were used to analyze the corrosion of a weld material of ferrite and austenitic stainless steels. Based on surface, chemical and electrochemical analyses, it was concluded that corrosion occurrence was the result of the simultaneous activity of contact corrosion (ferrite and austenitic material conjuction, stress corrosion (originating from deformed ferrite structure and inter-granular corrosion (due to chromium carbide precipitation. The value of corrosion potential of –0.53 V shows that this weld, after the thermal treatment, is not able to repassivate a protective oxide film.

  1. Corrosion in the oil industry

    Energy Technology Data Exchange (ETDEWEB)

    Brondel, D. (Sedco Forex, Montrouge (France)); Edwards, R. (Schlumberger Well Services, Columbus, OH (United States)); Hayman, A. (Etudes et Productions Schlumberger, Clamart (France)); Hill, D. (Schlumberger Dowell, Tulsa, OK (United States)); Mehta, S. (Schlumberger Dowell, St. Austell (United Kingdom)); Semerad, T. (Mobil Oil Indonesia, Inc., Sumatra (Indonesia))

    1994-04-01

    Corrosion costs the oil industry billions of dollars a year, a fact that makes the role of the corrosion engineer an increasingly important one. Attention is paid to how corrosion affects every aspect of exploration and production, from offshore rigs to casing. Also the role of corrosion agents such as drilling and production fluids is reviewed. Methods of control and techniques to monitor corrosion are discussed, along with an explanation of the chemical causes of corrosion. 21 figs., 32 refs.

  2. Investigation on the Recent Research Trend in the Corrosion Behaviour of Stainless Steel Weldment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)

    2011-06-15

    The research trend in the corrosion behaviour of stainless steel weldment has been reviewed. The welding technology plays an important role in the fabrication of structure such as chemical plant, power plant, because welding can influence various factors in the performance of plant and equipment. This has led to an increasing attention towards the corrosion behaviour of weldment which has been one of the major issues for both welding and corrosion research engineers. The aim of this paper is to give a short survey of the recent technical trends of welding and corrosion including the electrochemical corrosion, stress corrosion cracking, and corrosion fatigue in connection with the welding materials, welding process, and welding fabrication. This study covers the corrosion behaviour of stainless steel weldment collected from the COMPENDEX DB analysis of published papers, research subject and research institutes.

  3. Influence of localized deformation on A-286 austenitic stainless steel stress corrosion cracking in PWR primary water; Influence de la localisation de la deformation sur la corrosion sous contrainte de l'acier inoxydable austenitique A-286 en milieu primaire des REP

    Energy Technology Data Exchange (ETDEWEB)

    Savoie, M

    2007-01-15

    Irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steels is known to be a critical issue for structural components of nuclear reactor cores. The deformation of irradiated austenitic stainless steels is extremely heterogeneous and localized in deformation bands that may play a significant role in IASCC. In this study, an original approach is proposed to determine the influence of localized deformation on austenitic stainless steels SCC in simulated PWR primary water. The approach consists in (i) performing low cycle fatigue tests on austenitic stainless steel A-286 strengthened by {gamma}' precipitates Ni{sub 3}(Ti,Al) in order to shear and dissolve the precipitates in intense slip bands, leading to a localization of the deformation within and in (ii) assessing the influence of these {gamma}'-free localized deformation bands on A-286 SCC by means of comparative CERT tests performed on specimens with similar yield strength, containing or not {gamma}'-free localized deformation bands. Results show that strain localization significantly promotes A-286 SCC in simulated PWR primary water at 320 and 360 C. Moreover, A-286 is a precipitation-hardening austenitic stainless steel used for applications in light water reactors. The second objective of this work is to gain insights into the influence of heat treatment and metallurgical structure on A-286 SCC susceptibility in PWR primary water. The results obtained demonstrate a strong correlation between yield strength and SCC susceptibility of A-286 in PWR primary water at 320 and 360 C. (author)

  4. Metallurgical and mechanical parameters controlling alloy 718 stress corrosion cracking resistance in PWR primary water; Facteurs metallurgiques et mecaniques controlant l'amorcage de defauts de corrosion sous contrainte dans l'alliage 718 en milieu primaire des reacteurs a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Deleume, J

    2007-11-15

    Improving the performance and reliability of the fuel assemblies of the pressurized water reactors requires having a perfect knowledge of the operating margins of both the components and the materials. The choice of alloy 718 as reference material for this study is justified by the industrial will to identify the first order parameters controlling the excellent resistance of this alloy to Stress Corrosion Cracking (SCC). For this purpose, a specific slow strain rate (SSR) crack initiation test using tensile specimen with a V-shaped hump in the middle of the gauge length was developed and modeled. The selectivity of such SSR tests in simulated PWR primary water at 350 C was clearly established by characterizing the SCC resistance of nine alloy 718 thin strip heats. Regardless of their origin and in spite of a similar thermo-mechanical history, they did not exhibit the same susceptibility to SCC crack initiation. All the characterized alloy 718 heats develop oxide scale of similar nature for various exposure times to PWR primary medium in the temperature range [320 C - 360 C]. {delta} phase precipitation has no impact on alloy 718 SCC initiation behavior when exposed to PWR primary water, contrary to interstitial contents and the triggering of plastic instabilities (PLC phenomenon). (author)

  5. Comparison of microstructure and corrosion properties of Al-Zn-Mg-Cu alloys 7150 and 7010

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-chang; FAN Xi-gang; REN Shi-yu; ZHANG Xin-mei; ZHANG Bao-you

    2006-01-01

    The influence of coarse Cu-bearing particles, matrix and subgrain boundary precipitates on the stress corrosion susceptibility of the Al-Zn-Mg-Cu alloys was investigated. The strength of 7150 alloy is about 15 MPa higher than that of 7010 alloy.The 7010 alloy exhibits higher resistance to stress corrosion cracking as compared with the 7150 alloy. The coarse Cu-bearing particles are detrimental to the resistance to stress corrosion cracking. The increase of size of matrix and subgrain boundary precipitates decreases the susceptibility of stress corrosion. The anodic dissolution and hydrogen embrittlement govern the cracking process. The severity of stress corrosion cracking is shown to be related to the coarse Cu-bearing particles, matrix and subgrain precipitates in Al-Zn-Mg-Cu alloys.

  6. Research needs for corrosion control and prevention in energy conservation systems

    Energy Technology Data Exchange (ETDEWEB)

    Brooman, E.W.; Hurwitch, J.W.

    1985-06-01

    A group of 28 electrochemists, materials scientists and corrosion engineers was brought together to determine if the government could have a role as a focal point for corrosion R and D, discuss opportunities in fundamental research and solving corrosion problems, and develop a research agenda. Participants from government, industry and academia assembled into four technical discussion groups: localized corrosion, general corrosion, high temperature corrosion, and corrosion control and prevention. Research needs were identified, discussed, then assigned a figure of merit. Some 44 corrosion control and prevention topics were identified as having a high priority for consideration for funding. Another 35 topics were identified as having a medium priority for funding. When classified according to corrosion phenomenon, the areas which should receive the most attention are molten salt attack, crevice corrosion, stress-corrosion cracking, erosion-corrosion, pitting attack, intergranular attack and corrosion fatigue. When classified according to the sector or system involved, those which should receive the most attention are chemical processes, transportation, buildings and structures, electric power generation, and batteries and fuel cells.

  7. Stress Corrosion - Induced Cracking and Failure Analysis of Tubing Coupling at Oil Well%P110E油管接箍应力腐蚀开裂失效分析

    Institute of Scientific and Technical Information of China (English)

    韩燕; 谢俊峰; 赵密锋; 宋文文; 蔡锐

    2013-01-01

    西部油田某井油管因接箍开裂而落井.通过宏观分析、理化性能检测、金相显微镜、扫描电镜(SEM)、能谱仪、X射线衍射仪(XRD)等对该井开裂接箍进行了失效分析.结果表明:接箍开裂属于硫化物应力腐蚀开裂,该井硫化氢含量较高是接箍开裂的主要原因,此接箍材料不适宜在含硫环境下使用.%String falling was caused at an oil well of Tarim Oilfield by tubing coupling cracking. Thus macro - observation and physical-chemical property monitoring were combined with analyses by metallograpriic microscope, scanning electron microscope, energy dispersive spectrometer and X - ray diffractometer to seek for the causes leading to failure of the broken tubing coupling. Results indicate that the cracking of the tubing coupling is mainly due to sulfide stress corrosion, and a high content of hydrogen sulfide in the oil well accounts for the cracking of the tubing coupling, which means that relevant tubing coupling material is unsuitable for use in S-containing environment.

  8. Structural Composites Corrosive Management by Computational Simulation

    Science.gov (United States)

    Chamis, Christos C.; Minnetyan, Levon

    2006-01-01

    A simulation of corrosive management on polymer composites durability is presented. The corrosive environment is assumed to manage the polymer composite degradation on a ply-by-ply basis. The degradation is correlated with a measured Ph factor and is represented by voids, temperature, and moisture which vary parabolically for voids and linearly for temperature and moisture through the laminate thickness. The simulation is performed by a computational composite mechanics computer code which includes micro, macro, combined stress failure, and laminate theories. This accounts for starting the simulation from constitutive material properties and up to the laminate scale which exposes the laminate to the corrosive environment. Results obtained for one laminate indicate that the ply-by-ply managed degradation degrades the laminate to the last one or the last several plies. Results also demonstrate that the simulation is applicable to other polymer composite systems as well.

  9. Carbon Dioxide Corrosion:

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup

    2008-01-01

    CO2 corrosion is a general problem in the industry and it is expensive. The focus of this study is an oil gas production related problem. CO2 corrosion is observed in offshore natural gas transportation pipelines. A general overview of the problem is presented in chapter 1. The chemical system co...

  10. Avionics Corrosion Control Study

    Science.gov (United States)

    1974-01-01

    found at seacoast (harsn) environnents is the most destructive. Differences in electrolte concentration and oxygen concentration promote corrosion...against corrosion by acting as moisture and gas barriers. CMCVIT B0.4ID *COATINGS Polyurethane’s, cprxies, silicones, and polystyrenes are the most

  11. Anomalous dissolution of metals and chemical corrosion

    Directory of Open Access Journals (Sweden)

    DRAGUTIN M. DRAZIC

    2005-03-01

    Full Text Available An overview is given of the anomalous behavior of some metals, in particular Fe and Cr, in acidic aqueous solutions during anodic dissolution. The anomaly is recognizable by the fact that during anodic dissolutionmore material dissolves than would be expected from the Faraday law with the use of the expected valence of the formed ions. Mechanical disintegration, gas bubble blocking, hydrogen embrittlement, passive layer cracking and other possible reasons for such behavior have been discussed. It was shown, as suggested by Kolotyrkin and coworkers, that the reason can be, also, the chemical reaction in which H2O molecules with the metal form metal ions and gaseous H2 in a potential independent process. It occurs simultaneously with the electrochemical corrosion process, but the electrochemical process controls the corrosion potential. On the example of Cr in acid solution itwas shown that the reason for the anomalous behavior is dominantly chemical dissolution, which is considerably faster than the electrochemical corrosion, and that the increasing temperature favors chemical reaction, while the other possible reasons for the anomalous behavior are of negligible effect. This effect is much smaller in the case of Fe, but exists. The possible role of the chemical dissolution reacton and hydrogen evolution during pitting of steels and Al and stress corrosion cracking or corrosion fatigue are discussed.

  12. Prediction of Corrosion of Advanced Materials and Fabricated Components

    Energy Technology Data Exchange (ETDEWEB)

    A. Anderko; G. Engelhardt; M.M. Lencka (OLI Systems Inc.); M.A. Jakab; G. Tormoen; N. Sridhar (Southwest Research Institute)

    2007-09-29

    -base alloys, stainless steels and copper-nickel alloys and (2) the effects of heat treatment on localized corrosion. Excellent agreement with experimental data has been obtained for alloys in various environments, including acids, bases, oxidizing species, inorganic inhibitors, etc. Further, a probabilistic model has been established for predicting the long-term damage due to localized corrosion on the basis of short-term inspection results. This methodology is applicable to pitting, crevice corrosion, stress corrosion cracking and corrosion fatigue. Finally, a comprehensive model has been developed for predicting sensitization of Fe-Ni-Cr-Mo-W-N alloys and its effect on localized corrosion. As a vehicle for the commercialization of this technology, OLI Systems has developed the Corrosion Analyzer, a software tool that is already used by many companies in the chemical process industry. In process design, the Corrosion Analyzer provides the industry with (1) reliable prediction of the tendency of base alloys for localized corrosion as a function of environmental conditions and (2) understanding of how to select alloys for corrosive environments. In process operations, the software will help to predict the remaining useful life of equipment based on limited input data. Thus, users will also be able to identify process changes, corrosion inhibition strategies, and other control options before costly shutdowns, energy waste, and environmental releases occur. With the Corrosion Analyzer, various corrosion mitigation measures can be realistically tested in a virtual laboratory.

  13. Caustic leaching of high-level radioactive tank sludge: A critical literature review

    Energy Technology Data Exchange (ETDEWEB)

    McGinnis, C.P.; Welch, T.D.; Hunt, R.D.

    1997-12-31

    The Department of Energy (DOE) must treat and safely dispose of its radioactive tank contents, which can be separated into high-level waste (HLW) and low-level waste (LLW) fractions. Since the unit costs of treatment and disposal are much higher for HLW than for LLW, technologies to reduce the amount of HLW are being developed. A key process currently being studied to reduce the volume of HLW sludges is called enhanced sludge washing (ESW). This process removes, by water washes, soluble constituents such as sodium salts, and the washed sludge is then leached with 2--3 M NaOH at 60--100 C to remove nonradioactive metals such as aluminum. The remaining solids are considered to be HLW while the solutions are LLW after radionuclides such as {sup 137}Cs have been removed. Results of bench-scale tests have shown that the ESW will probably remove the required amounts of inert constituents. While both experimental and theoretical results have shown that leaching efficiency increases as the time and temperature of the leach are increased, increases in the caustic concentration above 2--3 M will only marginally improve the leach factors. However, these tests were not designed to validate the assumption that the caustic used in the ESW process will generate only a small increase (10 Mkg) in the amount of LLW; instead, the test conditions were selected to maximize leaching in a short period and used more water and caustic than is planned during full-scale operations. Even though calculations indicate that the estimate for the amount of LLW generated by the ESW process appears to be reasonable, a detailed study of the amount of LLW from the ESW process is still required. If the LLW analysis indicates that sodium management is critical, then a more comprehensive evaluation of the clean salt process or caustic recycle would be needed. Finally, experimental and theoretical studies have clearly demonstrated the need for the control of solids formation during and after leaching.

  14. Caustic leaching of high-level radioactive tank sludge: A critical literature review

    Energy Technology Data Exchange (ETDEWEB)

    McGinnis, C.P.; Welch, T.D.; Hunt, R.D.

    1998-08-01

    The Department of Energy (DOE) must treat and safely dispose of its radioactive tank contents, which can be separated into high-level waste (HLW) and low-level waste (LLW) fractions. Since the unit costs of treatment and disposal are much higher for HLW than for LLW, technologies to reduce the amount of HLW are being developed. A key process currently being studied to reduce the volume of HLW sludges is called enhanced sludge washing (ESW). This process removes, by water washes, soluble constituents such as sodium salts, and the washed sludge is then leached with 2--3 M NaOH at 60--100 C to remove nonradioactive metals such as aluminum. The remaining solids are considered to be HLW while the solutions are LLW after radionuclides such as {sup 137}Cs have been removed. Results of bench-scale tests have shown that the ESW will probably remove the required amounts of inert constituents. While both experimental and theoretical results have shown that leaching efficiency increases as the time and temperature of the leach are increased, increases in the caustic concentration above 2--3 M will only marginally improve the leach factors. However, these tests were not designed to validate the assumption that the caustic used in the ESW process will generate only a small increase (10 Mkg) in the amount of LLW; instead the test conditions were selected to maximize leaching in a short period and used more water and caustic than is planned during full-scale operations. Even though calculations indicate that the estimate for the amount of LLW generated by the ESW process appears to be reasonable, a detailed study of the amount of LLW from the ESW process is still required. If the LLW analysis indicates that sodium management is critical, then a more comprehensive evaluation of the clean salt process or caustic recycle would be needed. Finally, experimental and theoretical studies have clearly demonstrated the need for the control of solids formation during and after leaching.

  15. Characterization of irregular seeds on gibbsites precipitated from caustic aluminate solutions

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-hui; CHEN Qi-yuan; YIN Zhou-lan; YIN Zhi-min

    2006-01-01

    The irregular surface of seeds on which gibbsites are precipitated from caustic aluminate solutions, was investigated according to the fractal theory. Two kinds of fractal dimensions were used to characterize these irregularity. Box-dimension and spectral dimension are based on the SEM images of seeds and diffusive dynamic equation ofthe precipitation respectively. Both these two dimensions are affected by the reaction temperature, evolved with different reaction conditions and can reflect the influence of irregularity of seeds on the precipitation rate. Box dimension is fit for the characterization of the irregular morphology of seeds, while spectral dimension can explain the fractal dynamic behavior.

  16. Process for converting sodium nitrate-containing, caustic liquid radioactive wastes to solid insoluble products

    Science.gov (United States)

    Barney, Gary S.; Brownell, Lloyd E.

    1977-01-01

    A method for converting sodium nitrate-containing, caustic, radioactive wastes to a solid, relatively insoluble, thermally stable form is provided and comprises the steps of reacting powdered aluminum silicate clay, e.g., kaolin, bentonite, dickite, halloysite, pyrophyllite, etc., with the sodium nitrate-containing radioactive wastes which have a caustic concentration of about 3 to 7 M at a temperature of 30.degree. C to 100.degree. C to thereby entrap the dissolved radioactive salts in the aluminosilicate matrix. In one embodiment the sodium nitrate-containing, caustic, radioactive liquid waste, such as neutralized Purex-type waste, or salts or oxide produced by evaporation or calcination of these liquid wastes (e.g., anhydrous salt cake) is converted at a temperature within the range of 30.degree. C to 100.degree. C to the solid mineral form-cancrinite having an approximate chemical formula 2(NaAlSiO.sub.4) .sup.. xSalt.sup.. y H.sub.2 O with x = 0.52 and y = 0.68 when the entrapped salt is NaNO.sub.3. In another embodiment the sodium nitrate-containing, caustic, radioactive liquid is reacted with the powdered aluminum silicate clay at a temperature within the range of 30.degree. C to 100.degree. C, the resulting reaction product is air dried eitheras loose powder or molded shapes (e.g., bricks) and then fired at a temperature of at least 600.degree. C to form the solid mineral form-nepheline which has the approximate chemical formula of NaAlSiO.sub.4. The leach rate of the entrapped radioactive salts with distilled water is reduced essentially to that of the aluminosilicate lattice which is very low, e.g., in the range of 10.sup.-.sup.2 to 10.sup.-.sup.4 g/cm.sup.2 -- day for cancrinite and 10.sup.-.sup.3 to 10.sup.-.sup.5 g/cm.sup.2 -- day for nepheline.

  17. Demonstration of Caustic-Side Solvent Extraction with Savannah River Site High Level Waste

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D.

    2001-08-27

    Researchers successfully demonstrated the chemistry and process equipment of the Caustic-Side Solvent Extraction (CSSX) flowsheet for the decontamination of high level waste using a 33-stage, 2-cm centrifugal contactor apparatus at the Savannah River Technology Center. This represents the first CSSX process demonstration using Savannah River Site (SRS) high level waste. Three tests lasting 6, 12, and 48 hours processed simulated average SRS waste, simulated Tank 37H/44F composite waste, and Tank 37H/44F high level waste, respectively.

  18. Monitoring corrosion rates and localised corrosion in low conductivity water

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2006-01-01

    Monitoring of low corrosion rates and localised corrosion in a media with low conductivity is a challenge. In municipal district heating, quality control may be improved by implementing on-line corrosion monitoring if a suitable technique can be identified to measure both uniform and localised...... corrosion. Electrochemical techniques (LPR, EIS, crevice corrosion current) as well as direct measurement techniques (high-sensitive electrical resistance, weight loss) have been applied in operating plants. Changes in the corrosion processes are best monitored in non-aggressive, low conductivity media...... with sensitive electrical resistance technique and crevice corrosion current measurements....

  19. An evaluation of the susceptibility of V-4Cr-4Ti to stress corrosion cracking in room temperature DIII-D water

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, R.J.; Jones, R.H. [Pacific Northwest National Lab., Richland, WA (United States); Johnson, W.R.

    1997-04-01

    Two fatigue precracked compact tension (CT) specimens of V-4Cr-4Ti were statically loaded to a stress intensity factor of about 30 MPa{radical}m in room temperature DIII-D water. The first specimen was tested for a period of about 30 days and the second specimen for about 54 days. At the conclusion of each test the specimens were fractured, and the fracture surfaces examined with a scanning electron microscope (SEM) to determine if SCC had occurred. No SCC was found in either test specimen.

  20. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    OpenAIRE

    Xuming Zhang; Guosong Wu; Xiang Peng; Limin Li; Hongqing Feng; Biao Gao; Kaifu Huo; Chu, Paul K.

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface c...

  1. Caustic waterflooding demonstration project: Ranger Zone, Long Beach Unit, Wilmington Field, California. Third annual report, June 1978-May 1979

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, E.H.

    1979-12-01

    A caustic-enhanced waterflooding pilot test is being conducted in the Ranger Reservoir of the Long Beach Unit, Wilmington Field, California. Evaluation of entrapment and entrainment caustic flooding in Ranger Zone cores was continued. The caustic-only (entrapment) core floods failed to demonstrate improved behavior. Based on the unfavorable results of all tests of the entrapment mechanism, further laboratory work and flooding in the pilot with caustic alone have been eliminated from the project's plans. Some of the year's caustic-salt (entrainment) core floods in contrast showed both substantial recovery and WOR improvement. The poorer overall entrainment core flood results obtained in the year may be due to the core material, a smaller preflush volume used or the crude oil employed. Core flood testing where sodium silicate is substituted for some of the sodium hydroxide, was continued. The primary set of caustic water-oil dehydration tests was completed. The test softening of produced waters was completed and the results evaluated; produced water softening was found to be an economically feasible alternative to the use of fresh water. The preflush injection facilities became operational in January 1979 with the pilot's preflush officially begun April 15, 1979. The alkaline injection facility was expanded in scope to permit use of both sodium silicate and sodium hydroxide; its completion in late 1979 is anticipated with the alkaline-salt injection scheduled to begin at that time. The base case reservoir simulator prediction of the pilot under continued waterflooding was completed. This prediction provided the base line from which incremental alkaline flood production will be determined, as the test has now been declared a qualified tertiary enhanced recovery project by DOE's Economic Regulatory Administration. Major well repair/redrill work continued to be necessary exceeding earlier increased cost estimates.

  2. Corrosion Inhibitors for Reinforced Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Steel corrosion in reinforced concrete structures has been a major problem across the U.S. Steel-reinforced concrete structures are continually subject to attack by corrosion brought on by naturally occurring environmental conditions. FerroGard, a corrosion inhibitor, developed by Sika Corporation, penetrates hardened concrete to dramatically reduce corrosion by 65% and extend the structure's service life.

  3. Automated Methods Of Corrosion Measurements

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers; Andersen, Jens Enevold Thaulov; Reeve, John Ch

    1997-01-01

    The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell.......The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell....

  4. The Corrosion and Preservation of Iron Antiques.

    Science.gov (United States)

    Walker, Robert

    1982-01-01

    Discusses general corrosion reactions (iron to rust), including corrosion of iron, sulfur dioxide, chlorides, immersed corrosion, and underground corrosion. Also discusses corrosion inhibition, including corrosion inhibitors (anodic, cathodic, mixed, organic); safe/dangerous inhibitors; and corrosion/inhibition in concrete/marble, showcases/boxes,…

  5. Corrosion and failure processes in high-level waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Mahidhara, R.K.; Elleman, T.S.; Murty, K.L. [North Carolina State Univ., Raleigh, NC (United States)

    1992-11-01

    A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

  6. Localized corrosion information using high resolution measurement devices

    DEFF Research Database (Denmark)

    Ambat, Rajan

    2005-01-01

    to control the solution flow at the tip. Through addition of reference and counter electrodes, the pipette system becomes a microscopic electrochemical cell, which can then be used with high precision to determine the electrochemical characteristics of the microstructural region of interest. The capability...... of the technique could be further enhanced by adding new features such as high resolution video visualization systems, fretting/tribo-corroson attachments, and also by integrating it with stress corrosion testing, corrosion investigation of concrete for a few to name with. The corrosion group in MPT, Technical...

  7. Corrosion control in mining technology

    Energy Technology Data Exchange (ETDEWEB)

    Telekesi, J.

    1985-01-01

    An overview of corrosion effects in mining technology and the importance of protection is presented. The most common corrosion processes and effects are summarized and the system and criteria of their avoidance are discussed in detail. Preventive measures are recommended to decrease possible corrosion effects including the selection of corrosion-resistive constructions, to use protective coatings and inhibition techniques and some other protection possibilities where applicable. The organization aspects and the economic impact of corrosion control in mining are discussed.

  8. Corrosion-resistant uranium

    Science.gov (United States)

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  9. Origami constraints on the initial-conditions arrangement of dark-matter caustics and streams

    CERN Document Server

    Neyrinck, Mark C

    2012-01-01

    In a cold-dark-matter universe, cosmological structure formation proceeds in rough analogy to origami folding. Dark matter occupies a three-dimensional 'sheet,' non-intersecting in six-dimensional velocity-position phase space. At early times, the sheet was flat like an origami sheet, i.e. velocities were essentially zero. The present paper further illustrates this analogy, and identifies a result of origami mathematics that applies to cosmology. We define caustics in the initial conditions Lagrangian space) as surfaces in this sheet, along which the sheet has folded. The regions outlined by these caustics, which we call streams, may be colored according to the two possible orientations of initial basis vectors, a two-coloring such that adjacent streams are not colored the same. While this may not have clear observational consequences, it is a severe restriction on connectivity, since there are no bounds on the number of colors required to color a general arrangement of three-dimensional regions. Then, measur...

  10. Direct anodic hydrochloric acid and cathodic caustic production during water electrolysis

    Science.gov (United States)

    Lin, Hui-Wen; Cejudo-Marín, Rocío; Jeremiasse, Adriaan W.; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

    2016-02-01

    Hydrochloric acid (HCl) and caustic (NaOH) are among the most widely used chemicals by the water industry. Direct anodic electrochemical HCl production by water electrolysis has not been successful as current commercially available electrodes are prone to chlorine formation. This study presents an innovative technology simultaneously generating HCl and NaOH from NaCl using a Mn0.84Mo0.16O2.23 oxygen evolution electrode during water electrolysis. The results showed that protons could be anodically generated at a high Coulombic efficiency (i.e. ≥ 95%) with chlorine formation accounting for 3 ~ 5% of the charge supplied. HCl was anodically produced at moderate strengths at a CE of 65 ± 4% together with a CE of 89 ± 1% for cathodic caustic production. The reduction in CE for HCl generation was caused by proton cross-over from the anode to the middle compartment. Overall, this study showed the potential of simultaneous HCl and NaOH generation from NaCl and represents a major step forward for the water industry towards on-site production of HCl and NaOH. In this study, artificial brine was used as a source of sodium and chloride ions. In theory, artificial brine could be replaced by saline waste streams such as Reverse Osmosis Concentrate (ROC), turning ROC into a valuable resource.

  11. Additives effects on crystallization and morphology in a novel caustic aluminate solution decomposition process

    Institute of Scientific and Technical Information of China (English)

    Ying ZHANG; Sbili ZHENG; Yifei ZHANG; Hongbin XU; Yi ZHANG

    2009-01-01

    A novel process of caustic aluminate solution decomposition by alcohol medium was developed by the Institute of Process Engineering, Chinese Academy of Sciences in order to solve the problem of low decomposi-tion ratio in the traditional Bayer seeded hydrolysis process. In this research, effects of additives on the crystallization ratio, secondary particle size and morphol-ogy of aluminum hydroxide in the new process were studied to obtain high-quality products. On the basis of primary selection of additives, an orthogonal design L9(34)was used as a chemometric method to investigate the effects of additives. The studied parameters include the reaction style, quantity of additives, caustic soda concen-tration, as well as the combination manner. The crystal-lization ratios of sodium aluminate solution and crystal size of aluminum hydroxide, determined by ICP-OES, SEM and MLPSA (Malvern Laser Particle Size Analyzer), were used to evaluate the effects of the additives. The results showed that different combination manners could promote agglomeration or dispersion. An additive composed by Tween 80 and PEG 200 could promote agglomeration,while a spot of PEG species had a relatively strong dispersion effect. However, the additives had little effects on the crystallization ratios. According to the Raman spectra result, the added alcohol medium might serve as a kind of solvent.

  12. Corrosion Inhibitors for Aluminum.

    Science.gov (United States)

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  13. The Mineralogy of Microbiologically Influenced Corrosion

    Science.gov (United States)

    2015-01-01

    synthesis of these minerals, with the possible exception of pyrite, requires H2S pressures higher than those found in shallow waters. Direct electron...deposits by slime-forming organisms in as- sociation with iron- and manganese-depositing bacteria. Ammonia -producing bacteria were isolated from scale...and organic material on the admiralty brass tubes suffering ammonia -induced stress corrosion cracking. 5.4 CASE STUDIES Few investigators have

  14. Surface films and corrosion of copper

    Energy Technology Data Exchange (ETDEWEB)

    Hilden, J.; Laitinen, T.; Maekelae, K.; Saario, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of the copper is not expected to be the limiting factor in the waste repository environment when estimating the life-time of the canister construction. However, different forms of localised corrosion, i.e. pitting, stress corrosion cracking, or environmentally assisted creep fracture may cause premature failure of the copper shield. Of the probable constituents in the groundwater, nitrites, chlorides, sulphides and carbonates have been suggested to promote localised corrosion of copper. The main assumption made in planning this research program is that the surface films forming on copper in the repository environment largely determine the susceptibility of copper to the different forms of localised corrosion. The availability of reactants, which also may become corrosion rate limiting, is investigated in several other research programs. This research program consists of a set of successive projects targeted at characterising the properties of surface films on copper in repository environment containing different detrimental anions. A further aim was to assess the significance of the anion-induced changes in the stability of the oxide films with regard to localised corrosion of copper. This report summarises the results from a series of investigations on properties of surface films forming on copper in water of pH = 8.9 at temperature of 80 deg C and pressure of 2 MPa. The main results gained so far in this research program are as follows: The surface films forming on copper in the thermodynamic stability region of monovalent copper at 80 deg C consist of a bulk part (about 1 mm thick) which is a good ionic and electronic conductor, and an outer, interfacial layer (0.001 - 0.005 mm thick) which shows p-type semiconductor

  15. Cuspidal caustic and focusing of acoustical waves generated by a parametric array onto a concave reflecting surface

    Science.gov (United States)

    Castagnède, Bernard; Sahraoui, Sohbi; Tournat, Vincent; Tahani, Najat

    2009-09-01

    The present Note is devoted to the study of the so-called cuspidal caustic at the surface of a hemi-cylindrical reflector illuminated with plane waves. In order to generate low frequency (e.g. in the range of 4 kHz) acoustical plane waves, a commercially available parametric array has been used. It produces powerful ultrasonic carrier waves at 40 kHz which can be electronically modulated between 200 Hz and 10 kHz. Further self-demodulation process during propagation in air generates an ultra-directive acoustical field (i.e. quasi-planar wavefronts) enabling to accurately study the focusing process occurring along the cuspidal caustic. The focusing coefficient can be computed locally by using two numerical tools, on one hand by computing the density of tangent rays to the caustic, and on the other hand by using some numerical results provided by a ray tracing algorithm. Some preliminary experimental data are then provided in order to validate the numerical predictions (spatial position of the caustic and focusing coefficient). To cite this article: B. Castagnède et al., C. R. Mecanique 337 (2009).

  16. Copper corrosion under expected conditions in a deep geologic repository

    Energy Technology Data Exchange (ETDEWEB)

    King, F. [Integrity Corrosion Consulting Ltd, Calgary, Alberta (Canada); Ahonen, L. [Geological Survey of Finland, Espoo (Finland); Taxen, C. [Swedish Corrosion Inst., Stockholm (Sweden); Vuorinen, U. [VTT Chemical Technology, Espoo (Finland); Werme, L. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2001-12-01

    Copper has been the corrosion barrier of choice for the canister in the Swedish and Finnish, nuclear waste disposal programmes for over 20 years. During that time many studies have been carried out on the corrosion behaviour of copper under conditions likely to exist in an underground nuclear disposal repository located in he Fenno-Scandian bedrock. This review is a summary of what has been learnt about the long- term behaviour of the corrosion barrier during this period and what the implications of this knowledge are for the predicted service life of the canisters. The review is based on the existing knowledge from various nuclear waste management programs around the world and from the open literature.Various areas are considered: the expected evolution of the geochemical conditions in the groundwater and of the repository environment, the thermodynamics of copper corrosion, corrosion before and during saturation of the compacted bentonite buffer by groundwater, general and localized corrosion following saturation of the compacted bentonite buffer, stress corrosion cracking, radiation effects, the implications of corrosion on the service life of the canister, and areas for further study. Much has been learnt about the long-term corrosion behaviour of copper canisters over the past 20 years. The majority of the information reviewed here is drawn from the Swedish/Finnish and Canadian programmes. Despite differences in scientific approach, and canister and repository design, the results of these two programmes both suggest that copper provides an excellent corrosion barrier in an underground repository. The conclusion drawn from this review is that the original prediction made in 1978 of canister lifetimes exceeding 100,000 years remains valid.

  17. Copper corrosion under expected conditions in a deep geologic repository

    Energy Technology Data Exchange (ETDEWEB)

    King, F.; Ahonen, L.; Taxen, C.; Vuorinen, U.; Werme, L

    2002-01-01

    Copper has been the corrosion barrier of choice for the canister in the Swedish and Finnish, nuclear waste disposal programmes for over 20 years. During that time many studies have been carried out on the corrosion behaviour of copper under conditions likely to exist in an underground nuclear disposal repository located in the Fenno-Scandian bedrock. This review is a summary of what has been learnt about the long-term behaviour of the corrosion barrier during this period and what the implications of this knowledge are for the predicted service life of the canisters. The review is based on the existing knowledge from various nuclear waste management programs around the world and from the open literature. Various areas are considered: the expected evolution of the geochemical conditions in the groundwater and of the repository environment, the thermodynamics of copper corrosion, corrosion before and during saturation of the compacted bentonite buffer by groundwater, general and localized corrosion following saturation of the compacted bentonite buffer, stress corrosion cracking, radiation effects, the implications of corrosion on the service life of the canister, and areas for further study. Much has been learnt about the long-term corrosion behaviour of copper canisters over the past 20 years. The majority of the information reviewed here is drawn from the Swedish/Finnish and Canadian programmes. Despite differences in scientific approach, and canister and repository design, the results of these two programmes both suggest that copper provides an excellent corrosion barrier in an underground repository. The conclusion drawn from this review is that the original prediction made in 1978 of canister lifetimes exceeding 100,000 years remains valid. (orig.)

  18. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold...... is reached causing the formation of anodic and cathodic regions along the reinforcement. Critical chloride thresholds, randomly distributed along the reinforcement sur-face, link the initiation and propagation phase of reinforcement corrosion. To demonstrate the potential use of the developed model......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

  19. Study on Three Cases of Corrosion Failures of Refinery Equipment%炼油厂设备腐蚀故障失效分析三例

    Institute of Scientific and Technical Information of China (English)

    孙亮; 黄梓友; 郑明光

    2012-01-01

    In the study of 3 corrosion failure cases of refinery equipment, i.e. corrosion leakage of recycle oil/crude oil heat exchanger in atmospheric - vacuum distillation unit overhead, failure of pipeline upstream of inlet mixer of caustic wash drum of reactor effluent of sulfuric acid alkylation unit and corrosion leakage of steam generator in gasoline and diesel hydrotreating unit, the causes of corrosion failures of refinery equipment were analyzed. The results demonstrated that, the corrosion leakage of atmospheric -vacuum distillation unit overhead recycle oil/crude oil heat exchanger was caused by tube side media (overhead recycle oil) ; The corrosion was the result of H20 - HC1 system produced by HC1 dew formation. The pipeline upstream of inlet mixer of caustic wash drum of reactor effluent of sulfuric acid alkylation unit failed because of accelerated flow velocity caused by Ca vaporization in the low - pressure zone in the mixing of reactor effluent and hot caustic water due to the inappropriate ways of caustic addition. In addition, the water in caustic liquid diluted the sulfuric acid carried over with the reactor effluent, leading to serious corrosion of 20 alloy steel. The leakage of steam generator in gasoline and diesel hydrotreating unit was mainly caused by shell side media, water or fabrication defects of connection of heat exchanger tubes and shell plates. Prevention measures are recommended based upon different corrosion conditions.%结合炼油厂常减压蒸馏装置顶循环油/原油换热器管束泄漏;硫酸烷基化单元反应流出物碱洗罐入口混合器前管段穿孔和汽柴油加氢精制单元柴油蒸汽发生器泄漏等三例设备腐蚀案例进行了失效原因分析。分析结果表明:常减压蒸馏装置顶循环油/原油换热器管束泄漏由管程介质即顸循环引起,为HCl结露产生的H,0-HCl体系腐蚀所致;硫酸烷基化单元反应流出物碱洗罐入口混合器前管段穿孔由

  20. THE CHEMICAL AND RADIATION RESISTANCE OF POLYPHENYLENE SULFIIDE AS ENCOUNTERED IN THE MODULAR CAUSTIC SIDE SOLVENT EXTRACTION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.; Herman, D.; Poirier, M.; Fink, S.

    2011-06-30

    Polyphenylene sulfide (PPS) is a semicrystalline polymer with excellent engineering plastic properties and suitable processing temperatures. PPS can also be made containing branches (using a trifunctional monomer) and with crosslinked microstructure (when curing the monomer at high temperature in the presence of oxygen). PPS is made from the condensation reaction between para-dichlorobenzene and sodium sulfide with the assistance of a catalyst (to lower the activation barrier). The synthesis conditions for making PPS has evolved since its invention in the 1960's to the optimal conditions developed by the Philips Corporation in the 1970's. The resulting polymer consists of chemically stable molecular moieties such as benzene rings and ether like sulfur linkages between the aromatic rings. Polyphenylene sulfide (PPS) is extremely resistant to gamma irradiation, caustic solution, and dilute nitric acid. PPS is the material of construction for the coalescers used in the Modular Caustic-Side Solvent Extraction Unit (MCU). After applying the equivalent of 3.3 E8 rad (330 Mrad), or the equivalent of 11 years of gamma irradiation (assuming a stripping solution concentration of 7.5 Ci/gal), and several months of exposures to 3M caustic solution and caustic salt simulant, no dimensional changes nor chemical changes were detected in PPS whether the PPS was in fiber form or in a composite with E-glass fibers. However, PPS acts as a media for heterogeneous nucleation. In particular, PPS appears to favor aluminosilicate formation in saturated solutions of aluminum and silicon in caustic environments. Parallel testing, in progress, is examining the stability of PPS when exposed to the new solvent formulation under development for MCU. Preliminary data, after two months of exposure, demonstrates PPS is stable to the new solvent.

  1. EFRT M-12 Issue Resolution: Caustic-Leach Rate Constants from PEP and Laboratory-Scale Tests

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A.; Rassat, Scot D.; Eslinger, Paul W.; Aaberg, Rosanne L.; Aker, Pamela M.; Golovich, Elizabeth C.; Hanson, Brady D.; Hausmann, Tom S.; Huckaby, James L.; Kurath, Dean E.; Minette, Michael J.; Sundaram, S. K.; Yokuda, Satoru T.

    2010-01-01

    Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed and operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes” of the External Flowsheet Review Team (EFRT) issue response plan.( ) The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. The PEP also includes non-prototypic ancillary equipment to support the core processing. The work described in this report addresses caustic leaching under WTP conditions, based on tests performed with a Hanford waste simulant. Because gibbsite leaching kinetics are rapid (gibbsite is expected to be dissolved by the time the final leach temperature is reached), boehmite leach kinetics are the main focus of the caustic-leach tests. The tests were completed at the laboratory-scale and in the PEP, which is a 1/4.5-scale mock-up of key PTF process equipment. Two laboratory-scale caustic-leach tests were performed for each of the PEP runs. For each PEP run, unleached slurry was taken from the PEP caustic-leach vessel for one batch and used as feed for both of the corresponding laboratory-scale tests.

  2. The Caustic Alkali-free Water Extraction Agents for Treating Inner Mongolia Oil Sands

    Institute of Scientific and Technical Information of China (English)

    Shen Zhibing; Zhang Juntao; Zhang Jie; Liang Shengrong

    2014-01-01

    The caustic alkali-free water extraction agents were studied for treating the oil sands excavated from Inner Mon-golia, China. Several kinds of chemical reagents were evaluated, among which sodium carbonate (SC), sodium dodecyl benzene sulfonate (SD) and sodium chloride were conifrmed as composite solutes. Their proportion was optimized by an orthogonal test. The optimum proportion of the composite agent covered 0.03%of SD, 0.50%of sodium chloride, 3.00%of SC, with the rest composed of water. The optimal operating condition was also conifrmed. The oil sands were extracted at the following optimized conditions:a treating time of 15 min, a temperature of 80℃and an extraction agent/feed ratio of 1:1, with the bitumen yield reaching more than 96%. The extraction agent after separation from the bitumen product can be recycled for reuse to carve out a good environmentally friendly route.

  3. Predictive Factors of Gastrointestinal Caustic Injury According to Clinical and Endoscopic Findings

    Directory of Open Access Journals (Sweden)

    Cherie Quingking

    2013-03-01

    Full Text Available Background: Ingestion of caustic substances is the main reason for referral to Philippines National Poison Management and Control Center among other causes of acute poisoning. Rapid assessment of severity of injury is important for treatment and prognosis of these cases. This study was aimed to investigate the correlation of clinical factors with severity of gastrointestinal (GI mucosal injury. Methods: In this retrospective study, a total of 105 patients were included. Patients were categorized into two groups including 35 patients with low grade and 70 patients with high grade GI injury to compare the predictive value of clinical findings. Results: Mean (SD age of patients was 27 (10 and 47% of patients were male. Oral burns (P

  4. Probe of Multi-electron Dynamics in Xenon by Caustics in High Order Harmonic Generation

    CERN Document Server

    Faccialà, Davide; Bruner, Barry D; Ciriolo, Anna G; De Silvestri, Sandro; Devetta, Michele; Negro, Matteo; Soifer, Hadas; Stagira, Salvatore; Dudovich, Nirit; Vozzi, Caterina

    2016-01-01

    We investigated the giant resonance in Xenon by high-order harmonic generation spectroscopy driven by a two-color field. The addition of a non-perturbative second harmonic component parallel to the driving field breaks the symmetry between neighboring sub-cycles resulting in the appearance of spectral caustics at two distinct cut-off energies. By controlling the phase delay between the two color components it is possible to tailor the harmonic emission in order to amplify and isolate the spectral feature of interest. In this paper we demonstrate how this control scheme can be used to investigate the role of electron correlations that give birth to the giant resonance in Xenon. The collective excitations of the giant dipole resonance in Xenon combined with the spectral manipulation associated with the two color driving field allow to see features that are normally not accessible and to obtain a quantitative good agreement between the experimental results and the theoretical predictions.

  5. Probe of Multielectron Dynamics in Xenon by Caustics in High-Order Harmonic Generation

    Science.gov (United States)

    Faccialà, D.; Pabst, S.; Bruner, B. D.; Ciriolo, A. G.; De Silvestri, S.; Devetta, M.; Negro, M.; Soifer, H.; Stagira, S.; Dudovich, N.; Vozzi, C.

    2016-08-01

    We investigated the giant resonance in xenon by high-order harmonic generation spectroscopy driven by a two-color field. The addition of a nonperturbative second harmonic component parallel to the driving field breaks the symmetry between neighboring subcycles resulting in the appearance of spectral caustics at two distinct cutoff energies. By controlling the phase delay between the two color components it is possible to tailor the harmonic emission in order to amplify and isolate the spectral feature of interest. In this Letter we demonstrate how this control scheme can be used to investigate the role of electron correlations that give birth to the giant resonance in xenon. The collective excitations of the giant dipole resonance in xenon combined with the spectral manipulation associated with the two-color driving field allow us to see features that are normally not accessible and to obtain a good agreement between the experimental results and the theoretical predictions.

  6. K-Area/Caustic Basin Groundwater Monitoring Report. Second quarter 1993

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C.Y.

    1993-09-01

    During second quarter 1993, samples from the KAC monitoring wells at the K-Area Acid/Caustic Basin were collected and analyzed for indicator parameters, groundwater quality parameters, parameters indicating suitability as drinking water, and other constituents. Monitoring results that exceeded the final Primary Drinking Water Standards (PDWS) or the Savannah River Site (SRS) flagging criteria or turbidity standard during the quarter are discussed in this report. No analytes exceeded the final PDWS during second quarter 1993. Aluminum exceeded its Flag 2 criterion in wells KAC 6, 7, and 9. Iron exceeded the Flag 2 criterion in wells KAC 6 and 7, and specific conductance exceeded the Flag 2 criterion in well KAC 9. No samples exceeded the SRS turbidity standard.

  7. Free-fall accretion and emitting caustics in wind-fed X-ray sources

    Science.gov (United States)

    Illarionov, Andrei F.; Beloborodov, Andrei M.

    2001-05-01

    In wind-fed X-ray binaries the accreting matter is Compton-cooled and falls freely on to the compact object. The matter has a modest angular momentum l and accretion is quasi-spherical at large distances from the compact object. Initially small non-radial velocities grow in the converging supersonic flow and become substantial in the vicinity of the accretor. The streamlines with l>(GMR*)1/2 (where M and R* are the mass and radius of the compact object) intersect outside R* and form a two-dimensional caustic which emits X-rays. The streamlines with low angular momentum, lorbital phase of the binary. The accretor then appears as a `Moon-like' X-ray source.

  8. Effect of solvent addition sequence on lycopene extraction efficiency from membrane neutralized caustic peeled tomato waste.

    Science.gov (United States)

    Phinney, David M; Frelka, John C; Cooperstone, Jessica L; Schwartz, Steven J; Heldman, Dennis R

    2017-01-15

    Lycopene is a high value nutraceutical and its isolation from waste streams is often desirable to maximize profits. This research investigated solvent addition order and composition on lycopene extraction efficiency from a commercial tomato waste stream (pH 12.5, solids ∼5%) that was neutralized using membrane filtration. Constant volume dilution (CVD) was used to desalinate the caustic salt to neutralize the waste. Acetone, ethanol and hexane were used as direct or blended additions. Extraction efficiency was defined as the amount of lycopene extracted divided by the total lycopene in the sample. The CVD operation reduced the active alkali of the waste from 0.66 to lycopene efficiently from tomato processing byproducts.

  9. Synthesis of ZnS thin films from aqueous caustic of trisodium citrate and their properties

    Directory of Open Access Journals (Sweden)

    Martyn A. Sozanskyi

    2015-12-01

    Full Text Available Zinc sulfide (ZnS thin films due to their properties are widely used in various electronic optical devices. They are produced by several methods, among which – vacuum sublimation, high frequency sputtering method, quasiclosed volume method, sol-gel method, electrodeposition. These methods have high energy consumption which increases the price of ZnS thin films. Aim: The aim of this work is to establish the optimal parameters of the synthesis of ZnS thin films of the aqueous caustic and the correlation between content of zinc in the synthesized films determined by the method of stripping voltammetry and thickness, structural, morphological and optical parameters. Materials and Methods: The ZnS thin films were obtained from aqueous caustics of zinc-containing salt using chemical deposition. Fresh solution of zinc-containing salt, trisodium citrate (Na3C6H5O7 as a complexing agent, thiourea ((NH22CS and ammonium hydroxide (NH4OH was used for the synthesis of ZnS films by chemical deposition. The deposition was performed on prepared glass substrates with the area of 5,76 cm2. Results: The phase mixture of the films has been determined. It showed the presence of ZnS compounds in the cubic modification (sphalerite. Stripping voltammetry was used to determine the mass of zinc in the ZnS films on various conditions of synthesis, namely on the concentration of the initial zinc-containing salt, trisodium citrate, thiourea, deposition time and temperature. The surface morphology, optical properties, the thickness of the ZnS resulting films have been studied. Conclusions: The optimal conditions for the synthesis of ZnS films were found based on these data. Three-dimensional surface morphology of ZnS film studies showed its smoothness, uniformity, integrity and confirmed the correctness of determining the optimal synthesis parameters.

  10. Next Generation Solvent Development for Caustic-Side Solvent Extraction of Cesium

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Birdwell, Joseph F. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Bonnesen, Peter V. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2014-03-01

    This report summarizes the FY 2010 and 2011 accomplishments at Oak Ridge National Laboratory (ORNL) in developing the Next Generation Caustic-Side Solvent Extraction (NG-CSSX) process, referred to commonly as the Next Generation Solvent (NGS), under funding from the U.S. Department of Energy, Office of Environmental Management (DOE-EM), Office of Technology Innovation and Development. The primary product of this effort is a process solvent and preliminary flowsheet capable of meeting a target decontamination factor (DF) of 40,000 for worst-case Savannah River Site (SRS) waste with a concentration factor of 15 or higher in the 18-stage equipment configuration of the SRS Modular Caustic-Side Solvent Extraction Unit (MCU). In addition, the NG-CSSX process may be readily adapted for use in the SRS Salt Waste Processing Facility (SWPF) or in supplemental tank-waste treatment at Hanford upon appropriate solvent or flowsheet modifications. Efforts in FY 2010 focused on developing a solvent composition and process flowsheet for MCU implementation. In FY 2011 accomplishments at ORNL involved a wide array of chemical-development activities and testing up through single-stage hydraulic and mass-transfer tests in 5-cm centrifugal contactors. Under subcontract from ORNL, Argonne National Laboratory (ANL) designed a preliminary flowsheet using ORNL cesium distribution data, and Tennessee Technological University confirmed a chemical model for cesium distribution ratios (DCs) as a function of feed composition. Inter laboratory efforts were coordinated with complementary engineering tests carried out (and reported separately) by personnel at Savannah River National Laboratory (SRNL) and Savannah River Remediation (SRR) with helpful advice by Parsons Engineering and General Atomics on aspects of possible SWPF implementation.

  11. Next Generation Solvent (NGS): Development for Caustic-Side Solvent Extraction of Cesium

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Birdwell, Jr, Joseph F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bonnesen, Peter V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Delmau, Laetitia Helene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duncan, Nathan C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ensor, Dale [Tennessee Technological Univ., Cookeville, TN (United States); Hill, Talon G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Denise L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rajbanshi, Arbin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roach, Benjamin D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Szczygiel, Patricia L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sloop, Jr., Frederick V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stoner, Erica L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Williams, Neil J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-03-01

    This report summarizes the FY 2010 and 2011 accomplishments at Oak Ridge National Laboratory (ORNL) in developing the Next Generation Caustic-Side Solvent Extraction (NG-CSSX) process, referred to commonly as the Next Generation Solvent (NGS), under funding from the U.S. Department of Energy, Office of Environmental Management (DOE-EM), Office of Technology Innovation and Development. The primary product of this effort is a process solvent and preliminary flowsheet capable of meeting a target decontamination factor (DF) of 40,000 for worst-case Savannah River Site (SRS) waste with a concentration factor of 15 or higher in the 18-stage equipment configuration of the SRS Modular Caustic-Side Solvent Extraction Unit (MCU). In addition, the NG-CSSX process may be readily adapted for use in the SRS Salt Waste Processing Facility (SWPF) or in supplemental tank-waste treatment at Hanford upon appropriate solvent or flowsheet modifications. Efforts in FY 2010 focused on developing a solvent composition and process flowsheet for MCU implementation. In FY 2011 accomplishments at ORNL involved a wide array of chemical-development activities and testing up through single-stage hydraulic and mass-transfer tests in 5-cm centrifugal contactors. Under subcontract from ORNL, Argonne National Laboratory (ANL) designed a preliminary flowsheet using ORNL cesium distribution data, and Tennessee Technological University confirmed a chemical model for cesium distribution ratios (DCs) as a function of feed composition. Interlaboratory efforts were coordinated with complementary engineering tests carried out (and reported separately) by personnel at Savannah River National Laboratory (SRNL) and Savannah River Remediation (SRR) with helpful advice by Parsons Engineering and General Atomics on aspects of possible SWPF implementation.

  12. Next Generation Solvent Performance in the Modular Caustic Side Solvent Extraction Process - 15495

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Tara E. [Savannah River Remediation, LLC., Aiken, SC (United States); Scherman, Carl [Savannah River Remediation, LLC., Aiken, SC (United States); Martin, David [Savannah River Remediation, LLC., Aiken, SC (United States); Suggs, Patricia [Savannah River Site (SRS), Aiken, SC (United States)

    2015-01-14

    Changes to the Modular Caustic Side Solvent Extraction Unit (MCU) flow-sheet were implemented in the facility. Implementation included changing the scrub and strip chemicals and concentrations, modifying the O/A ratios for the strip, scrub, and extraction contactor banks, and blending the current BoBCalixC6 extractant-based solvent in MCU with clean MaxCalix extractant-based solvent. During the successful demonstration period, the MCU process was subject to rigorous oversight to ensure hydraulic stability and chemical/radionuclide analysis of the key process tanks (caustic wash tank, solvent hold tank, strip effluent hold tank, and decontaminated salt solution hold tank) to evaluate solvent carryover to downstream facilities and the effectiveness of cesium removal from the liquid salt waste. Results indicated the extraction of cesium was significantly more effective with an average Decontamination Factor (DF) of 1,129 (range was 107 to 1,824) and that stripping was effective. The contactor hydraulic performance was stable and satisfactory, as indicated by contactor vibration, contactor rotational speed, and flow stability; all of which remained at or near target values. Furthermore, the Solvent Hold Tank (SHT) level and specific gravity was as expected, indicating that solvent integrity and organic hydraulic stability were maintained. The coalescer performances were in the range of processing results under the BOBCalixC6 flow sheet, indicating negligible adverse impact of NGS deployment. After the Demonstration period, MCU began processing via routine operations. Results to date reiterate the enhanced cesium extraction and stripping capability of the Next Generation Solvent (NGS) flow sheet. This paper presents process performance results of the NGS Demonstration and continued operations of MCU utilizing the blended BobCalixC6-MaxCalix solvent under the NGS flowsheet.

  13. Corrosion testing using isotopes

    Science.gov (United States)

    Hohorst, Frederick A.

    1995-12-05

    A method for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a substrate of material which is easily corroded by the medium, the substrate having a surface; a substantially chemically inert gas implanted into the substrate; and a sheet of the material whose resistance to corrosion is to be tested, the sheet being disposed against the surface of the substrate and having a defined thickness.

  14. Increased corrosion resistance of the AZ80 magnesium alloy by rapid solidification.

    Science.gov (United States)

    Aghion, E; Jan, L; Meshi, L; Goldman, J

    2015-11-01

    Magnesium (Mg) and Mg-alloys are being considered as implantable biometals. Despite their excellent biocompatibility and good mechanical properties, their rapid corrosion is a major impediment precluding their widespread acceptance as implantable biomaterials. Here, we investigate the potential for rapid solidification to increase the corrosion resistance of Mg alloys. To this end, the effect of rapid solidification on the environmental and stress corrosion behavior of the AZ80 Mg alloy vs. its conventionally cast counterpart was evaluated in simulated physiological electrolytes. The microstructural characteristics were examined by optical microscopy, SEM, TEM, and X-ray diffraction analysis. The corrosion behavior was evaluated by immersion, salt spraying, and potentiodynamic polarization. Stress corrosion resistance was assessed by Slow Strain Rate Testing. The results indicate that the corrosion resistance of rapidly solidified ribbons is significantly improved relative to the conventional cast alloy due to the increased Al content dissolved in the α-Mg matrix and the correspondingly reduced presence of the β-phase (Mg17 Al12 ). Unfortunately, extrusion consolidated solidified ribbons exhibited a substantial reduction in the environmental performance and stress corrosion resistance. This was mainly attributed to the detrimental effect of the extrusion process, which enriched the iron impurities and increased the internal stresses by imposing a higher dislocation density. In terms of immersion tests, the average corrosion rate of the rapidly solidified ribbons was <0.4 mm/year compared with ∼2 mm/year for the conventionally cast alloy and 26 mm/year for the rapidly solidified extruded ribbons.

  15. Severe Environmental Corrosion Erosion Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NETL’s Severe Environment Corrosion Erosion Facility in Albany, OR, allows researchers to safely examine the performance of materials in highly corrosive or erosive...

  16. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  17. Corrosion-resistant metallic coatings

    OpenAIRE

    F. Presuel-Moreno; M.A. Jakab; N. Tailleart; Goldman, M.; J. R. Scully

    2008-01-01

    We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned) to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic i...

  18. Corroding and Protecting of Surface Residual Stress With the Surface Hardening of Steel

    Institute of Scientific and Technical Information of China (English)

    ZOU Qing-hua

    2004-01-01

    The states of the stress with the surface hardening are analyzed, the related experiential formula of the stress -temperature and stress-depth hardened curves are set up, the protecting measures against hydrogen stress corrosion are discussed.

  19. Solving A Corrosion Problem

    Science.gov (United States)

    1979-01-01

    The corrosion problem, it turned out, stemmed from the process called electrolysis. When two different metals are in contact, an electrical potential is set up between them; when the metals are surrounded by an electrolyte, or a conducting medium, the resulting reaction causes corrosion, often very rapid corrosion. In this case the different metals were the copper grounding system and the ferry's aluminum hull; the dockside salt water in which the hull was resting served as the electrolyte. After identifying the source of the trouble, the Ames engineer provided a solution: a new wire-and-rod grounding system made of aluminum like the ferry's hull so there would no longer be dissimilar metals in contact. Ames research on the matter disclosed that the problem was not unique to the Golden Gate ferries. It is being experienced by many pleasure boat operators who are probably as puzzled about it as was the Golden Gate Transit Authority.

  20. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.