WorldWideScience

Sample records for sulphide stress corrosion

  1. Effect of sulphide on corrosion of copper in seawater

    OpenAIRE

    Gopalakrishna Pillai, A.G.

    1985-01-01

    The corrosion of ETP copper in natural seawater and putrid seawater has been studied. The corrosion rates and the sulphide content were monitored at regular intervals. In the absence of oxygen in the putrid media, the presence of sulphide favoured a reduction in the corrosion rate.

  2. Evaluation of the resistance of API 5L-X80 girth welds to sulphide stress corrosion cracking and hydrogen embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Forero, Adriana [Pontificia Universidade Catolica (PUC-Rio), Rio de Janeiro, RJ (Brazil); Ponciano, Jose A. [Universidade Federal do Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao em Engenharia; Bott, Ivani de S. [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ (Brazil). Dept. de Ciencia dos Materiais e Metalurgia

    2009-07-01

    The susceptibility of pipeline steels to stress corrosion cracking (SCC) depends on a series of factors ranging from the manufacture of the steel, the pipe fabrication and the assembly of the pipeline to the type of substances to be transported. The welding procedures adopted during the production and construction of the pipelines (field welding), can modify the properties of the base metal in the heat affected zone (HAZ), potentially rendering this region susceptible to SCC. This study evaluates the resistance of girth welds, in API 5L X80 pipes, to hydrogen embrittlement and to stress corrosion cracking in the presence of sulphides. The evaluation was performed according to NACE TM0177/96, Method A, applying the criterion of fracture/no fracture, and Slow Strain Rate Tensile tests (SSRT) were undertaken using a sodium thiosulphate solution according to the ASTM G129-00 Standard. According NACE requirements, the base metal was approved. The weld metal exhibited susceptibility to SCC in the presence of sulphides, failing in a period of less than 720h. This was confirmed by SSR tensile tests, where a significant decrease in the ultimate tensile strength, the elongation and the time to fracture were observed. The mechanism of fracture was transgranular. (author)

  3. Corrosion of copper alloys in sulphide containing district heting systems

    DEFF Research Database (Denmark)

    Thorarinsdottir, R.I.; Maahn, Ernst Emanuel

    1999-01-01

    Copper and some copper alloys are prone to corrosion in sulphide containing geothermal water analogous to corrosion observed in district heating systems containing sulphide due to sulphate reducing bacteria. In order to study the corrosion of copper alloys under practical conditions a test...... was carried out at four sites in the Reykjavik District Heating System. The geothermal water chemistry is different at each site. The corrosion rate and the amount and chemical composition of deposits on weight loss coupons of six different copper alloys are described after exposure of 12 and 18 months......, respectively. Some major differences in scaling composition and the degree of corrosion attack are observed between alloys and water types....

  4. A Study of Substituted Aliphatic Sulphides on the Corrosion Behaviour of Zinc in Ammonium Chloride Solution

    Directory of Open Access Journals (Sweden)

    R. Venckatesh

    2007-01-01

    Full Text Available Sulphur containing organic compounds decreases the corrosion rate by increasing the hydrogen over potential on zinc metal due to their electron donating groups. Their inhibiting effect was found to be associated with their adsorption on the active centers of the metal. The inhibition efficiencies of some aliphatic sulphides in ammonium chloride solution have been studied by weight loss studies, polarization and impedance measurements. The effect of substituent groups is correlated with their inhibition performance. These studies due to their relevance in Zn-Manganese dry batteries assume their importance.

  5. Global warming enhances sulphide stress in a key seagrass species (NW Mediterranean).

    Science.gov (United States)

    García, Rosa; Holmer, Marianne; Duarte, Carlos M; Marbà, Núria

    2013-12-01

    The build-up of sulphide concentrations in sediments, resulting from high inputs of organic matter and the mineralization through sulphate reduction, can be lethal to the benthos. Sulphate reduction is temperature dependent, thus global warming may contribute to even higher sulphide concentrations and benthos mortality. The seagrass Posidonia oceanica is very sensitive to sulphide stress. Hence, if concentrations build up with global warming, this key Mediterranean species could be seriously endangered. An 8-year monitoring of daily seawater temperature, the sulphur isotopic signatures of water (δ(34)S(water)), sediment (δ(34)SCRS ) and P. oceanica leaf tissue (δ(34)S(leaves)), along with total sulphur in leaves (TS(leaves)) and annual net population growth along the coast of the Balearic archipelago (Western Mediterranean) allowed us to determine if warming triggers P. oceanica sulphide stress and constrains seagrass survival. From the isotopic S signatures, we estimated sulphide intrusion into the leaves (F(sulphide)) and sulphur incorporation into the leaves from sedimentary sulphides (SS(leaves)). We observed lower δ(34)S(leaves), higher F(sulphide) and SS(leaves) coinciding with a 6-year period when two heat waves were recorded. Warming triggered sulphide stress as evidenced by the negative temperature dependence of δ(34)S(leaves) and the positive one of F(sulphide), TS(leaves) and SS(leaves). Lower P. oceanica net population growth rates were directly related to higher contents of TS(leaves). At equivalent annual maximum sea surface water temperature (SST(max)), deep meadows were less affected by sulphide intrusion than shallow ones. Thus, water depth acts as a protecting mechanism against sulphide intrusion. However, water depth would be insufficient to buffer seagrass sulphide stress triggered by Mediterranean seawater summer temperatures projected for the end of the 21st century even under scenarios of moderate greenhouse gas emissions, A1B

  6. Corrosion Product Film-Induced Stress Facilitates Stress Corrosion Cracking.

    Science.gov (United States)

    Wang, Wenwen; Zhang, Zhiliang; Ren, Xuechong; Guan, Yongjun; Su, Yanjing

    2015-06-11

    Finite element analyses were conducted to clarify the role of corrosion product films (CPFs) in stress corrosion cracking (SCC). Flat and U-shaped edge-notched specimens were investigated in terms of the CPF-induced stress in the metallic substrate and the stress in the CPF. For a U-shaped edge-notched specimen, the stress field in front of the notch tip is affected by the Young's modulus of the CPF and the CPF thickness and notch geometry. The CPF-induced tensile stress in the metallic substrate is superimposed on the applied load to increase the crack tip strain and facilitate localized plasticity deformation. In addition, the stress in the CPF surface contributes to the rupture of the CPFs. The results provide physical insights into the role of CPFs in SCC.

  7. 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

  8. Biotechnological sulphide removal with oxygen

    NARCIS (Netherlands)

    Buisman, C.

    1989-01-01

    This thesis deals with the development of a new process for biotechnological sulphide removal from wastewater, in which it is attempted to convert sulphide into elemental sulphur by colourless sulphur bacteria. The toxicity, corrosive properties, unpleasant odor and high oxygen demand of sulphide

  9. An investigation of the corrosive wear of steel balls in grinding of sulphide ores

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2015-06-01

    Full Text Available Ball mills are common grinding equipment in mineral processing industries. Ball wear results from three mechanisms namely impact, abrasion and corrosion. Of these, the corrosion mechanism is the least investigated, due to its chemical-electrochemical nature. Therefore, the aims of this research were to investigate the grinding chemistry influence (slurry pH, solid percentage, water chemistry and gas purging on corrosive wear of steel balls and to determine the contribution of corrosion mechanism to total wear of steel balls. The results indicated that the mass losses of steel balls could be reduced considerably by controlling the pulp chemistry inside the mill. In addition, the results showed that 73.51% of the corrosion products are generated from the oxidation of steel balls. It was also estimated that the corrosion mechanism accounts for 26.68% of the total wear of steel balls.

  10. Stress-corrosion cracking in metals

    Science.gov (United States)

    1971-01-01

    Criteria and recommended practices for preventing stress-corrosion cracking from impairing the structural integrity and flightworthiness of space vehicles are presented. The important variables affecting stress-corrosion cracking are considered to be the environment, including time and temperature; metal composition, and structure; and sustained tensile stress. For designing spacecraft structures that are free of stress-corrosion cracking for the service life of the vehicle the following rules apply: (1) identification and control of the environments to which the structure will be exposed during construction, storage, transportation, and use; (2) selection of alloy compositions and tempers which are resistant to stress-corrosion cracking in the identified environment; (3) control of fabrication and other processes which may introduce residual tensile stresses or damage the material; (4) limitation of the combined residual and applied tensile stresses to below the threshold stress level for the onset of cracking throughout the service life of the vehicle; and (5) establishment of a thorough inspection program.

  11. A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel

    Directory of Open Access Journals (Sweden)

    Robert E. Melchers

    2016-05-01

    Full Text Available The critical role of manganese sulphide (MnS inclusions for the initiation of the short-term growth of pitting or localized corrosion of low carbon steels has long been recognized. Classical results show that pitting probability and pitting severity increases with increased sulphide concentration for low carbon steels as a result of magnesium sulphides acting as local cathodes for initiating pitting corrosion. However, the iron carbides (cementite in steels can also act as local cathodes for initiation of pitting corrosion. Herein it is proposed that there is competition between pits for cathodic area and that this will determine the severity of pitting and general corrosion observed in extended exposures. Preliminary experimental data for immersion exposures of up to 56 days in natural seawater of three low carbon steels show, contrary to conventional wisdom, greater pit depths for the steels with lower S content. However, the pit depth results are consistent with lower C/S ratios. This is considered to support the concept of cathodic competition between C and S. It is proposed that this offers explanations for a number of other phenomena, including the thus far unexplained apparently higher reactivity of some MnS inclusions.

  12. Hydrogen Sulphide Corrosion of Carbon and Stainless Steel Alloys Immersed in Mixtures of Renewable Fuel Sources and Tested Under Co-processing Conditions

    Directory of Open Access Journals (Sweden)

    Gergely András

    2016-10-01

    Full Text Available In accordance with modern regulations and directives, the use of renewable biomass materials as precursors for the production of fuels for transportation purposes is to be strictly followed. Even though, there are problems related to processing, storage and handling in wide range of subsequent uses, since there must be a limit to the ratio of biofuels mixed with mineral raw materials. As a key factor with regards to these biomass sources pose a great risk of causing multiple forms of corrosion both to metallic and non-metallic structural materials. To assess the degree of corrosion risk to a variety of engineering alloys like low-carbon and stainless steels widely used as structural metals, this work is dedicated to investigating corrosion rates of economically reasonable engineering steel alloys in mixtures of raw gas oil and renewable biomass fuel sources under typical co-processing conditions. To model a desulphurising refining process, corrosion tests were carried out with raw mineral gasoline and its mixture with used cooking oil and animal waste lard in relative quantities of 10% (g/g. Co-processing was simulated by batch-reactor laboratory experiments. Experiments were performed at temperatures between 200 and 300ºC and a pressure in the gas phase of 90 bar containing 2% (m3/m3 hydrogen sulphide. The time span of individual tests were varied between 1 and 21 days so that we can conclude about changes in the reaction rates against time exposure of and extrapolate for longer periods of exposure. Initial and integral corrosion rates were defined by a weight loss method on standard size of coupons of all sorts of steel alloys. Corrosion rates of carbon steels indicated a linear increase with temperature and little variation with composition of the biomass fuel sources. Apparent activation energies over the first 24-hour period remained moderate, varying between 35.5 and 50.3 kJ mol−1. Scales developed on carbon steels at higher

  13. Strain rate effects in stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Parkins, R.N. (Newcastle upon Tyne Univ. (UK). Dept. of Metallurgy and Engineering Materials)

    1990-03-01

    Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic strain provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow strain tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that strain or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.

  14. Seacoast stress corrosion cracking of aluminum alloys

    Science.gov (United States)

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

    1981-01-01

    The stress corrosion cracking resistance of high strength, wrought aluminum alloys in a seacoast atmosphere was investigated and the results were compared with those obtained in laboratory tests. Round tensile specimens taken from the short transverse grain direction of aluminum plate and stressed up to 100 percent of their yield strengths were exposed to the seacoast and to alternate immersion in salt water and synthetic seawater. Maximum exposure periods of one year at the seacoast, 0.3 or 0.7 of a month for alternate immersion in salt water, and three months for synthetic seawater were indicated for aluminum alloys to avoid false indications of stress corrosion cracking failure resulting from pitting. Correlation of the results was very good among the three test media using the selected exposure periods. It is concluded that either of the laboratory test media is suitable for evaluating the stress corrosion cracking performance of aluminum alloys in seacoast atmosphere.

  15. Kinetic studies of stress-corrosion cracking

    Science.gov (United States)

    Noronha, P. J.

    1977-01-01

    Use of time-to-failure curves for stress-corrosion cracking processes may lead to incorrect estimates of structural life, if material is strongly dependent upon prestress levels. Technique characterizes kinetics of crackgrowth rates and intermediate arrest times by load-level changes.

  16. Stress Corrosion Cracking of Certain Aluminum Alloys

    Science.gov (United States)

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

    1983-01-01

    SC resistance of new high-strength alloys tested. Research report describes progress in continuing investigation of stress corrosion (SC) cracking of some aluminum alloys. Objective of program is comparing SC behavior of newer high-strength alloys with established SC-resistant alloy.

  17. Apollo experience report: The problem of stress-corrosion cracking

    Science.gov (United States)

    Johnson, R. E.

    1973-01-01

    Stress-corrosion cracking has been the most common cause of structural-material failures in the Apollo Program. The frequency of stress-corrosion cracking has been high and the magnitude of the problem, in terms of hardware lost and time and money expended, has been significant. In this report, the significant Apollo Program experiences with stress-corrosion cracking are discussed. The causes of stress-corrosion cracking and the corrective actions are discussed, in terminology familiar to design engineers and management personnel, to show how stress-corrosion cracking can be prevented.

  18. Corrosion Inhibition of Stress Corrosion Cracking and Localized Corrosion of Turbo-Expander Materials

    Science.gov (United States)

    Bavarian, Behzad; Zhang, Jia; Reiner, Lisa

    Stress corrosion cracking of 7050 aluminum alloy in the turbo expander and steam/gas turbine industry can cause catastrophic failures, especially for turbo machinery systems performing in hostile, corrosive environments. Commercially available inhibitors were investigated for their effectiveness in reducing and controlling the corrosion susceptibility. Inhibitor effectiveness was confirmed with electrochemical corrosion techniques. Polarization resistance increased with concentration of corrosion inhibitor due to film formation and displacement of water molecules. Cyclic polarization behavior for samples in the 1.0% to 10.0% inhibitor concentration showed a shift in the passive film breakdown potential. The substantial increase in the passive range has positive consequences for neutralizing pitting and crevice corrosion cell chemistry. The strain to failure and tensile strength determined from slow strain rate studies for the aluminum alloy showed pronounced improvement resulting from the inhibitors ability to mitigate SCC. Additionally, the fractographic analysis showed a changed morphology with ductile overload as the primary failure mode instead of transgranular or intergranular cracking.

  19. 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.

  20. Stress Corrosion of Ceramic Materials.

    Science.gov (United States)

    1983-10-01

    Scientifique Continentale du Verre , Charleroi, Belgium, 1962. Dunning, J.M., Effects of Aqueous Chemical Environments on Crack Propagation in Quartz, this volume...Symposium on Mechanical Strength of Glass and Ways of Improving It. Florence, Italy, September 25-29, 1961. Union Scientifique Continentale du Verre ...Florence, Italy, September 25-29, 1961. Union Scientifique Continentale du Verre , Charleroi, Belgium, 1962., 24. T.A. Michalske, "The Stress

  1. 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.

  2. Design Criteria for Controlling Stress Corrosion Cracking

    Science.gov (United States)

    Franklin, D. B.

    1987-01-01

    This document sets forth the criteria to be used in the selection of materials for space vehicles and associated equipment and facilities so that failure resulting from stress corrosion will be prevented. The requirements established herein apply to all metallic components proposed for use in space vehicles and other flight hardware, ground support equipment, and facilities for testing. These requirements are applicable not only to items designed and fabricated by MSFC (Marshall Space Flight Center) and its prime contractors, but also to items supplied to the prime contractor by subcontractors and vendors.

  3. 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)

  4. Resistance of Some Steels to Stress Corrosion Cracking

    Science.gov (United States)

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

    1982-01-01

    Evaluations of stress-corrosion cracking resistance of five high-strength low-alloy steels described in report now available. Steels were heat-treated to various tensile strengths and found to be highly resistant to stress-corrosion cracking.

  5. Probability of stress-corrosion fracture under random loading

    Science.gov (United States)

    Yang, J. N.

    1974-01-01

    Mathematical formulation is based on cumulative-damage hypothesis and experimentally-determined stress-corrosion characteristics. Under both stationary random loadings, mean value and variance of cumulative damage are obtained. Probability of stress-corrosion fracture is then evaluated, using principle of maximum entropy.

  6. Corrosion characteristics of unprotected post-tensioning strands under stress.

    Science.gov (United States)

    2014-05-01

    An investigation was conducted to determine the effect of stress condition : and environmental exposure on corrosion of post-tensioned strands during ungrouted periods. : Exposures for periods of up to 4 weeks of stressed, as-received strand placed i...

  7. 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.

  8. Controlling stress corrosion cracking in mechanism components of ground support equipment

    Science.gov (United States)

    Majid, W. A.

    1988-01-01

    The selection of materials for mechanism components used in ground support equipment so that failures resulting from stress corrosion cracking will be prevented is described. A general criteria to be used in designing for resistance to stress corrosion cracking is also provided. Stress corrosion can be defined as combined action of sustained tensile stress and corrosion to cause premature failure of materials. Various aluminum, steels, nickel, titanium and copper alloys, and tempers and corrosive environment are evaluated for stress corrosion cracking.

  9. Stress corrosion cracking in the earth

    Science.gov (United States)

    Das, S.; Scholz, C. H.

    1980-01-01

    Two fundamental concepts of fracture mechanics are used to develop a theory of the earthquake mechanism which specifically predicts observed time-dependent rupture phenomena such as slow earthquakes, postseismic rupture growth and afterslip, multiple events, foreshocks, and aftershocks. The theory also predicts that there must be a nucleation stage prior to an earthquake, and suggests a physical mechanism by which one earthquake may trigger another. Investigations show that all earthquakes must be preceded by a quasi-static slip over a portion of the rupture surfaces, although it may be difficult to detect in practice, and a study of delayed multiple events characterizes the strength of some barriers in the earth as having a stress corrosion index of about 24.

  10. Stress corrosion cracking of titanium alloys

    Science.gov (United States)

    May, R. C.; Beck, F. H.; Fontana, M. G.

    1971-01-01

    Experiments were conducted to study (1) the basic electrochemical behavior of titanium in acid chloride solutions and (2) the response of the metal to dynamic straining in the same evironment. The aim of this group of experiments was to simulate, as nearly as possible, the actual conditions which exist at the tip of a crack. One of the foremost theories proposed to explain the propagation of stress corrosion cracks is a hydrogen embrittlement theory involving the precipitation of embrittling titanium hydrides inside the metal near the crack tip. An initial survey of the basic electrochemical literature indicated that surface hydrides play a critical role in the electrochemistry of titanium in acid solutions. A comprehensive analysis of the effect of surface films, particularly hydrides, on the electrochemical behavior of titanium in these solution is presented.

  11. Stress corrosion cracking of AISI 321 stainless steel in acidic ...

    Indian Academy of Sciences (India)

    Unknown

    YANLIANG HUANG. Marine Corrosion and Protection Laboratory, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road,. Qingdao 266071, China. MS received 21 August 2001; revised 21 November 2001. Abstract. The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic chloride solution ...

  12. Grease Inhibits Stress-Corrosion Cracking In Bearing Race

    Science.gov (United States)

    Beatty, Robert F.; Mcvey, Scott E.

    1991-01-01

    Coating with suitable grease found to inhibit stress-corrosion cracking in bore of inner race of ball-bearing assembly operating in liquid oxygen. Protects bore and its corner radii from corrosion-initiating and -accelerating substances like moisture and contaminants, which enter during assembly. Operating life extended at low cost, and involves very little extra assembly time.

  13. Stress Corrosion-Cracking and Corrosion Fatigue Impact of IZ-C17+ Zinc Nickel on 4340 Steel

    Science.gov (United States)

    2017-05-17

    REPORT NO: NAWCADPAX/TIM-2016/189 STRESS CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL by...DEPARTMENT OF THE NAVY NAVAL AIR WARFARE CENTER AIRCRAFT DIVISION PATUXENT RIVER, MARYLAND NAWCADPAX/TIM-2016/189 STRESS ...5a. CONTRACT NUMBER STRESS CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL 5b. GRANT NUMBER 5c. PROGRAM

  14. The effect of deformation on stress corrosion of brass

    Directory of Open Access Journals (Sweden)

    A. Kadłuczka

    2010-07-01

    Full Text Available Brass are some of the most common copper alloys, both due to its characteristics and utility technology. Corrosion fracture after stress corrosion are the most common form of destruction of brass.This is particularly dangerous because of the lack of early, visible signal of decohesion of the material. It is therefore important to know exactly this phenomenon to design and manufacture heavy loaded industrial constructions exposed to aggressive environments, as wellas minimize the danger of destroying the structure. This paper presents the results of the influence of degree of plastic deformation on the stress corrosion of brass M63 grade. Material for the study were subjected to varying degrees of deformation. Research was conducted in the corrosive sea water environment. The tests were performed based on the method of BF. Brown beam test. Analyzing the results of stress corrosion tests it was found that the greater degree of deformation cause the greater resistance to stress corrosion fracture of this material. The paper also contains a characteristic scanning surfaces investigation of exemplary samples after stress corrosion tests.

  15. In Situ X-ray Microtomography of Stress Corrosion Cracking and Corrosion Fatigue in Aluminum Alloys

    Science.gov (United States)

    Singh, Sudhanshu S.; Stannard, Tyler J.; Xiao, Xianghui; Chawla, Nikhilesh

    2017-08-01

    Structural materials are subjected to combinations of stress and corrosive environments that work synergistically to cause premature failure. Therefore, studies on the combined effect of stress and corrosive environments on material behavior are required. Existing studies have been performed in two dimensions that are inadequate for full comprehension of the three-dimensional (3D) processes related to stress corrosion cracking (SCC) and corrosion-fatigue (CF) behavior. Recently, x-ray synchrotron tomography has evolved as an excellent technique to obtain the microstructure in 3D. Moreover, being nondestructive in nature, x-ray synchrotron tomography is well suited to study the evolution of microstructure with time (4D, or fourth dimension in time). This article presents our recent 4D studies on SCC and CF of Al 7075 alloys using x-ray synchrotron tomography.

  16. Stress-Corrosion Cracking in Martensitic PH Stainless Steels

    Science.gov (United States)

    Humphries, T.; Nelson, E.

    1984-01-01

    Precipitation-hardening alloys evaluated in marine environment tests. Report describes marine-environment stress-corrosion cracking (SCC) tests of three martensitic precipitation hardening (PH) stainless-steel alloys.

  17. [Stress-corrosion test of TIG welded CP-Ti].

    Science.gov (United States)

    Li, H; Wang, Y; Zhou, Z; Meng, X; Liang, Q; Zhang, X; Zhao, Y

    2000-12-01

    In this study TIG (Tungsten Inert Gas) welded CP-Ti were subjected to stress-corrosion test under 261 MPa in artificial saliva of 37 degrees C for 3 months. No significant difference was noted on mechanical test (P > 0.05). No color-changed and no micro-crack on the sample's surface yet. These results indicate that TIG welded CP-Ti offers excellent resistance to stress corrosion.

  18. Stress corrosion cracking properties of 15-5PH steel

    Science.gov (United States)

    Rosa, Ferdinand

    1993-01-01

    Unexpected occurrence of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15-5PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a highly acidified sodium chloride (NaCl) aqueous solution. The selected alloy for the study was a 15-5PH steel in the H900 condition. The slow strain rate technique was selected to test the metals specimens.

  19. Comparative Stress Corrosion Cracking and General Corrosion Resistance of Annealed and Hardened 440 C Stainless Steel - New Techniques in Stress Corrosion Testing

    Science.gov (United States)

    Mendreck, M. J.; Hurless, B. E.; Torres, P. D.; Danford, M. D.

    1998-01-01

    The corrosion and stress corrosion cracking (SCC) characteristics of annealed and hardened 440C stainless steel were evaluated in high humidity and 3.5-percent NaCl solution. Corrosion testing consisted of an evaluation of flat plates, with and without grease, in high humidity, as well as electrochemical testing in 3.5-percent NaCl. Stress corrosion testing consisted of conventional, constant strain, smooth bar testing in high humidity in addition to two relatively new techniques under evaluation at MSFC. These techniques involve either incremental or constant rate increases in the load applied to a precracked SE(B) specimen, monitoring the crack-opening-displacement response for indications of crack growth. The electrochemical corrosion testing demonstrated an order of magnitude greater general corrosion rate in the annealed 440C. All techniques for stress corrosion testing showed substantially better SCC resistance in the annealed material. The efficacy of the new techniques for stress corrosion testing was demonstrated both by the savings in time and the ability to better quantify SCC data.

  20. Corrosion and Stress Corrosion Behaviors of Low and Medium Carbon Steels in Agro-Fluid Media

    Directory of Open Access Journals (Sweden)

    Ayo Samuel AFOLABI

    2007-01-01

    Full Text Available Investigations were carried out to study critically the corrosion behaviour and Stress Corrosion Cracking (SCC of low and medium carbon steels in cassava and cocoa extracts by weight loss measurement and constant extension to fracture method respectively. The results obtained showed that medium carbon steel is more susceptible to corrosion than low carbon steel in both media. SCC is also more in medium carbon steel than low carbon steel in the two media under study. These deductions are due to higher carbon content in medium carbon steel coupled with various aggressive corrosion constituents contained in these media. Hydrogen embrittlement, as well as carbon cracking, is responsible for SCC of these materials in the agro-fluid media.

  1. High temperature and stress corrosion cracking of 310S austenitic stainless steel in wet chloride corrosive environment

    Directory of Open Access Journals (Sweden)

    T. Pornpibunsompop

    2018-01-01

    Full Text Available High temperature corrosion and stress corrosion cracking of 310S austenitic stainless steel in wet chloride environment at a high temperature was investigated. The result showed that high temperature corrosion products mostly consisted of ferrous oxides and chromium oxides. Chloride ions attacked a chromium passive film and strongly reacted with iron and chromium. As a result of metal chlorides being volatized, tunnel of pores inside corrosion layer existed. Intergranular stress corrosion cracking was observed. The oxide originated on surface could act as a crack initiator and a crack propagation would progress along grain boundaries and particularly along tunnel of pores.

  2. 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...

  3. Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels

    Science.gov (United States)

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

    1980-01-01

    The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels.

  4. 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.

  5. Statistical model of stress corrosion cracking based on extended ...

    Indian Academy of Sciences (India)

    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 ...

  6. Statistical model of stress corrosion cracking based on extended ...

    Indian Academy of Sciences (India)

    2016-09-07

    Sep 7, 2016 ... Abstract. In the previous paper (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 ...

  7. Statistical model of stress corrosion cracking based on extended ...

    Indian Academy of Sciences (India)

    2013-12-01

    Dec 1, 2013 ... Abstract. 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 vari- ational principle under approximately supposed thermal equilibrium. In that model the functionals are expressed ...

  8. Statistical model of stress corrosion cracking based on extended ...

    Indian Academy of Sciences (India)

    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 ...

  9. Reducing Stress-Corrosion Cracking in Bearing Alloys

    Science.gov (United States)

    Paton, N. E.; Dennies, D. P.; Lumsden, I., J.b.

    1986-01-01

    Resistance to stress-corrosion cracking in some stainless-steel alloys increased by addition of small amounts of noble metals. 0.75 to 1.00 percent by weight of palladium or platinum added to alloy melt sufficient to improve properties of certain stainless steels so they could be used in manufacture of high-speed bearings.

  10. Page 1 Stress corrosion cracking of austenitic stainless steels 691 ...

    Indian Academy of Sciences (India)

    Stress corrosion cracking of austenitic stainless steels 691 and crack growth per event computed from acoustic emission and crack growth data are presented in table 3. The crack growth per event varies from less than a micron for a solution annealed material to 15 pm for 10% cold worked material. 4.4 Fractographic ...

  11. Stress corrosion cracking of AISI 321 stainless steel in acidic ...

    Indian Academy of Sciences (India)

    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 ...

  12. Study on Corrosion and Stress Corrosion Cracking Behaviors of AZ31 Alloy in Sodium Sulfate Solution

    Science.gov (United States)

    He, Xiuli; Yan, Zhifeng; Liang, Hongyu; Wei, Yinghui

    2017-05-01

    The potentiodynamic polarization test and slow strain rate tensile test were carried out in 3.5 wt.% Na2SO4 solution with different pH values (2, 7, and 12). It was found that the SCC susceptibility of AZ31 magnesium alloy in 3.5 wt.% Na2SO4 solution was deteriorated significantly with the decreasing pH. This was consistent with the electrochemical properties. There were filiform corrosion forms on the specimen surface after slow strain rate tensile test in 3.5 wt.% Na2SO4 solution, which indicated the characteristics of general corrosion. Moreover, there were multiple stress corrosion crack initiation sources. The SCC fracture of AZ31 magnesium alloy in air was a mix type, while it was cleavage fracture in 3.5 wt.% Na2SO4 solution.

  13. 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.

  14. 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.

  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. 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)

  17. 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...

  18. Stress corrosion cracking of metal matrix composites: Modeling and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.H.

    1990-10-01

    The stress corrosion crack growth ate of metal matrix composites has been described by a model which is dependent on the length-to- diameter ({ell}/d) ratio and volume fraction of the reinforcing phase and matrix creep component. The model predicts a large dependence of the stress corrosion crack growth rate of a metal matrix composite on {ell}/d and matrix creep component and a small dependence on the volume fraction of reinforcement. Experimentally determined crack growth rates for 7090 Al/SiC tested in 3.5% NcCl solution, 6061 Al/SiC tested in moist air with NaCl and immersed in NaCl solution, and Mg/Al{sub 2}0{sub 3} tested in a chloride/chromate solution are all consistent with the model. The close correspondence between the model and experiment for a matrix creep stress exponent of 3 suggest that there is little corrosion damage to the reinforcing phase in these systems. 16 refs., 5 figs.

  19. Comparison of Stress Corrosion Cracking Susceptibility of Laser Machined and Milled 304 L Stainless Steel

    Science.gov (United States)

    Gupta, R. K.; Kumar, Aniruddha; Nagpure, D. C.; Rai, S. K.; Singh, M. K.; Khooha, Ajay; Singh, A. K.; Singh, Amrendra; Tiwari, M. K.; Ganesh, P.; Kaul, R.; Singh, B.

    2016-12-01

    Machining of austenitic stainless steel components is known to introduce significant enhancement in their susceptibility to stress corrosion cracking. The paper compares stress corrosion cracking susceptibility of laser machined 304 L stainless steel specimens with conventionally milled counterpart in chloride environment. With respect to conventionally milled specimens, laser machined specimens displayed more than 12 times longer crack initiation time in accelerated stress corrosion cracking test in boiling magnesium chloride as per ASTM G36. Reduced stress corrosion cracking susceptibility of laser machined surface is attributed to its predominantly ferritic duplex microstructure in which anodic ferrite phase was under compressive stress with respect to cathodic austenite.

  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. Corrosion of alloy 800H and the effect of surface-applied CeO2 in a sulphidizing/oxidizing/carburizing environment at 700°C

    NARCIS (Netherlands)

    Stroosnijder, M.F.; Guttmann, V.; Fransen, T.; de Wit, J.H.W.

    The corrosion behavior of a wrought austenitic Fe-20Cr-32Ni steel, Alloy 800H, was studied in a simulated coal-gasification atmosphere at 700°C for exposure times up to 2500 hr. The influence of preoxidation and CeO2-surface application followed by preoxidation on the corrosion resistance of this

  2. Addressing stress corrosion cracking on multi layer pipeline coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, Scott B.; Marr, James E. [Tuboscope Pipeline Services, Houston, TX (United States); Willmot, Martyn [Jotun Group (Norway); Norman, David [David Norman Corrosion Control, Cornwall (United Kingdom); Khera, Ashish [Allied Engineering, Portland, ME (United States)

    2005-07-01

    Stress corrosion cracking (SCC) is now recognized by operators worldwide as a significant threat to the safe operation of their pipeline systems. Gas, oil, and refined products lines have all been susceptible to this form of environmentally assisted cracking. As a result, operators and regulators have been incorporating data related to the development and prevalence of SCC into their risk management systems in order that they may effectively address this time-dependant threat. The National Association of Corrosion Engineers (NACE) published the first structured methodology for stress corrosion cracking direct assessment (SCCDA) in 2004 (RP0204-2004). Operators are now beginning to apply the methods outlined in the standard to assess their systems. Research and industry experience have shown that various pipeline coating systems can be more or less effective in preventing the formation and growth of SCC. Newer pipeline coatings, such as multi layer epoxy/extruded polyolefin systems have been widely regarded as effective coating systems to address the threat posed by SCC when they are properly applied. New field studies performed on a pipeline coated with a three layer epoxy/polyethylene system have raised the possibility that operators utilizing these types of coatings may need to reassess how they manage the SCC threat. (author)

  3. Stress corrosion cracking of several high strength ferrous and nickel alloys

    Science.gov (United States)

    Nelson, E. E.

    1971-01-01

    The stress corrosion cracking resistance of several high strength ferrous and nickel base alloys has been determined in a sodium chloride solution. Results indicate that under these test conditions Multiphase MP35N, Unitemp L605, Inconel 718, Carpenter 20Cb and 20Cb-3 are highly resistant to stress corrosion cracking. AISI 410 and 431 stainless steels, 18 Ni maraging steel (250 grade) and AISI 4130 steel are susceptible to stress corrosion cracking under some conditions.

  4. 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.

  5. Stress Corrosion Behavior of 12Cr Martensite Steel for Steam Turbine LP Blade

    Science.gov (United States)

    Tianjian, Wang; Yubing, Pei; Zhenhuan, Gao; Hua, Fan; Gongxian, Yang

    With the development of capacity and efficiency of coal-fired thermal power plant, the length of Low Pressure (LP) last-stage blade of steam turbine became longer. Therefore, the design static stress of blade gets closer or even higher than the yield strength of material. Because of the special operation condition of LP last stage blade, the stress corrosion crack of 12Cr-Ni-Mo-V-N Martensite stainless steel may happen especially at the root of the blade where designed the highest static stress. In this paper, the stress corrosion behavior of 12Cr-Ni-Mo-V-N Martensite stainless steels used for steam turbine LP last stage blade in 3vol% NaCl solution was studied, the constant stress is about 95%, 85%, 65% and 35% of yield stress respectively and the test was lasted for 3000 hours, the stress corrosion behavior was studied and then, the effect of shot penning strengthen for anti-stress corrosion property of 12Cr-Ni-Mo-V-N Martensitic steel was studied. The results showed that the purity of steel affects the stress corrosion behavior huge especially at the high and medium stress condition. The shot penning cannot enhances the anti-stress corrosion property of the 12Cr-Ni-Mo-V-N steel at high tensile constant stress condition, however it will make the anti-stress corrosion property better when the stress is low.

  6. 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.

  7. Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints

    OpenAIRE

    Vinoth Kumar, M.; Balasubramanian, V.; Rajakumar, S.; Albert, Shaju K.

    2015-01-01

    Super 304H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of t...

  8. Analysis of Alloy 600 and X-750 stress corrosion cracks

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C.D.; Lewis, N.; Krasodomski, H.

    1993-06-01

    A few months ago, KAPL evidence supported the view that Primary or Pure Water Stress Corrosion Cracking (PWSCC) of Alloy 600 results from a hydrogen mechanism. Figure 1 shows an Analytical Electron Microscope (AEM) analysis of a stress corrosion crack (SCC) crack in an A600 split tube U-bend specimen exposed to primary water at 338{degree}C (640{degrees}F) for 462 days. The features which appear to confirm a hydrogen mechanism are: (1) A very narrow (< 200 {angstrom}) crack with a sharp tip, nearly free of deposits. (2) No evidence of severe plastic deformation in the region immediately ahead of the crack tip. (3) A line of small voids preceding the main crack tip, of which the largest is about 5 x 10{sup {minus}6} cm in length. Shen and Shewmon proposed that PWSCC of Alloy 600 occurs due to small microvoids ahead of a main crack tip. The hypothesis is that such voids result from pockets of methane gas formed by the reaction of atomic hydrogen with carbon in the base metal. The voids are about 10 x 10{sup {minus}6} cm diameter, approximately a factor of 2 larger than the largest voids.

  9. Micromechanistic origin of irradiation-assisted stress corrosion cracking

    Science.gov (United States)

    Cui, Bai; McMurtrey, Michael D.; Was, Gary S.; Robertson, Ian M.

    2014-12-01

    A multi-scale study of the micromechanics of dislocation-grain boundary interactions in proton and ion-irradiated stainless steels is presented. Interactions of dislocation channels with grain boundaries result in slip transfer, discontinuous slip without or with slip along the grain boundary. The presence of the irradiation damage enhances the importance of the magnitude of the resolved shear stress on the slip system activated by the grain boundary to transfer slip across it. However, the selected slip system is still determined by the minimization of the grain boundary strain energy density condition. These findings have implications for modelling the mechanical properties of irradiated metals as well as in establishing the mechanism for disrupting the grain boundary oxide, which is a necessary prerequisite for irradiation-assisted stress corrosion cracking.

  10. Destructive Examinations on Divider Plates from Decommissioned Steam Generators Affected by Superficial Stress Corrosion Cracks

    Science.gov (United States)

    Miloudi, Salem; Firmin, Erwan; Deforge, Damien; Vaillant, François; Lemaire, Emmanuel

    Stress Corrosion Cracking of nickel alloys has been a major concern for all the Nuclear Power Plants over the last forty years. Since 2002, some cases of Stress Corrosion Cracking (SCC) have been reported on Steam Generator (SG) Divider Plates. However, evidence of propagation following the first detection has never been observed (based on nearly one hundred in-service inspections).

  11. Clean steels for steam turbine rotors—their stress corrosion cracking resistance

    Science.gov (United States)

    Magdowski, Ruth M.; Speidel, Markus O.

    1988-06-01

    This work presents the results of a comprehensive study concerning stress corrosion crack growth rates in steam turbine rotor steels exposed to hot water. The effects of stress intensity, temperature, and dissolved gases in the water have been investigated. Special attention has been given to the influence of impurities and alloying elements in the steel such as P, S, Mn, Si, Mo, and Ni, and to the effect of yield strength and fracture toughness on the growth rates of stress corrosion cracks. The results of this study clearly show that there exists a threshold stress intensity of about 20 MNm-3/2 above which the invariably intergranular stress corrosion cracks grow at a constant, stress-independent velocity. This plateau stress corrosion crack growth rate is not affected by the oxygen and carbon dioxide concentration in the water. The temperature and the yield strength of the steel have a strong influence on the growth rate of stress corrosion cracks. In contrast, there is no effect of the steel composition within the range investigated, neither of the impurity elements such as P and S, nor of the major alloying elements such as Mn, Si, Mo, and Ni. Steels with low fracture toughness due to temper embrittlement do not exhibit faster stress corrosion crack growth rates in water than nonembrittled steels. No direct relationship between intergranular temper embrittlement and intergranular stress corrosion crack growth in water can be demonstrated.

  12. Temperature factors effect on occurrence of stress corrosion cracking of main gas pipeline

    Science.gov (United States)

    Nazarova, M. N.; Akhmetov, R. R.; Krainov, S. A.

    2017-10-01

    The purpose of the article is to analyze and compare the data in order to contribute to the formation of an objective opinion on the issue of the growth of stress corrosion defects of the main gas pipeline. According to available data, a histogram of the dependence of defects due to stress corrosion on the distance from the compressor station was constructed, and graphs of the dependence of the accident density due to stress corrosion in the winter and summer were also plotted. Data on activation energy were collected and analyzed in which occurrence of stress corrosion is most likely constructed, a plot of activation energy versus temperature is plotted, and the process of occurrence of stress corrosion by the example of two different grades of steels under the action of different temperatures was analyzed.

  13. Influence of bovine serum albumin in Hanks' solution on the corrosion and stress corrosion cracking of a magnesium alloy.

    Science.gov (United States)

    Harandi, Shervin Eslami; Banerjee, Parama Chakraborty; Easton, Christopher D; Singh Raman, R K

    2017-11-01

    It is essential for any temporary implant to possess adequate strength to maintain their mechanical integrity under the synergistic effects of mechanical loading characteristics of human body and the corrosive physiological environment. Such synergistic effects can cause stress corrosion cracking (SCC). The aim of the present study is to investigate the effect of the addition of bovine serum albumin (BSA) to Hanks' solution in corrosion and SCC susceptibility of AZ91D magnesium alloy. The electrochemical impedance spectroscopy (EIS) results indicated that the addition of BSA increased corrosion resistance of the alloy during the first 48h of immersion and then decreased it rapidly. The energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses indicated adsorption of BSA on the alloy surface during initial hours of immersion. However, with the increasing immersion time, BSA chelated with the corrosion products causing disruption of the protective film; thus, it accelerated the corrosion of the alloy. Both the mechanical data and fractographic evidence have confirmed susceptibility of the alloy to SCC. However, in the presence of BSA, the alloy suffered greater SCC which was attributed to its increased susceptibility towards localized corrosion. Copyright © 2017. Published by Elsevier B.V.

  14. Prediction of sulphide build-up in filled sewer pipes.

    Science.gov (United States)

    Alani, Amir M; Faramarzi, Asaad; Mahmoodian, Mojtaba; Tee, Kong Fah

    2014-08-01

    Millions of dollars are being spent worldwide on the repair and maintenance of sewer networks and wastewater treatment plants. The production and emission of hydrogen sulphide has been identified as a major cause of corrosion and odour problems in sewer networks. Accurate prediction of sulphide build-up in a sewer system helps engineers and asset managers to appropriately formulate strategies for optimal sewer management and reliability analysis. This paper presents a novel methodology to model and predict the sulphide build-up for steady state condition in filled sewer pipes. The proposed model is developed using a novel data-driven technique called evolutionary polynomial regression (EPR) and it involves the most effective parameters in the sulphide build-up problem. EPR is a hybrid technique, combining genetic algorithm and least square. It is shown that the proposed model can provide a better prediction for the sulphide build-up as compared with conventional models.

  15. 49 CFR 192.929 - What are the requirements for using Direct Assessment for Stress Corrosion Cracking (SCCDA)?

    Science.gov (United States)

    2010-10-01

    ... Assessment for Stress Corrosion Cracking (SCCDA)? 192.929 Section 192.929 Transportation Other Regulations... requirements for using Direct Assessment for Stress Corrosion Cracking (SCCDA)? (a) Definition. Stress Corrosion Cracking Direct Assessment (SCCDA) is a process to assess a covered pipe segment for the presence...

  16. Stress Corrosion Cracking Behavior of Peened Friction Stir Welded 2195 Aluminum Alloy Joints

    Science.gov (United States)

    Hatamleh, Omar; Singh, Preet M.; Garmestani, Hamid

    2009-06-01

    The surface treatment techniques of laser and shot peening were used to investigate their effect on stress corrosion cracking (SCC) in friction stir welded (FSW) 2195 aluminum alloy joints. The investigation consisted of two parts: the first part explored the peening effects on slow strain rate testing (SSRT) in a 3.5% NaCl solution, while the second part investigated the effects of peening on corrosion while submerged in a 3.5% NaCl solution with no external loads applied. For the SSRT, the laser-peened samples demonstrated superior properties to the other samples, but no signs of corrosion pitting or SCC were evident on any of the samples. For the second part of the study, the FSW plates were inspected periodically for signs of corrosion. After 60 days there were signs of corrosion pitting, but no stress corrosion cracking was noticed in any of the peened and unpeened samples.

  17. 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.

  18. Surface aspects of pitting and stress corrosion cracking

    Science.gov (United States)

    Truhan, J. S., Jr.; Hehemann, R. F.

    1977-01-01

    The pitting and stress corrosion cracking of a stable austenitic stainless steel in aqueous chloride environments were investigated using a secondary ion mass spectrometer as the primary experimental technique. The surface concentration of hydrogen, oxygen, the hydroxide, and chloride ion, magnesium or sodium, chromium and nickel were measured as a function of potential in both aqueous sodium chloride and magnesium chloride environments at room temperature and boiling temperatures. It was found that, under anodic conditions, a sharp increase in the chloride concentration was observed to occur for all environmental conditions. The increase may be associated with the formation of an iron chloride complex. Higher localized chloride concentrations at pits and cracks were also detected with an electron microprobe.

  19. Stress corrosion cracking susceptibility of 18 Ni maraging steel

    Science.gov (United States)

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

    1974-01-01

    The stress corrosion cracking (SCC) resistance of 18Ni maraging steel (grades 200, 250, 300, and 350) was determined in 3.5 percent salt (NaCl) solution, synthetic sea water, high humidity, and outside MSFC atmosphere. All grades of the maraging steel were found to be susceptible to SCC in varying degrees according to their strengths, with the lowest strength steel (grade 200) being the least susceptible and the highest strength steel (grade 350), the most susceptible to SCC. The SCC resistance of 250 grade maraging steel was also evaluated in salt and salt-chromate solutions using fracture mechanics techniques. The threshold value, K sub SCC, was found to be approximately 44 MN/sq m square root m, (40 ksi square root in.) or 40 percent of the K sub Q value.

  20. Influence of hydrogen on corrosion and stress induced cracking of stainless steel

    OpenAIRE

    Kivisäkk, Ulf

    2010-01-01

    Hydrogen is the smallest element in the periodical table. It has been shown in several studies that hydrogen has a large influence on the corrosion and cracking behaviour of stainless steels. Hydrogen is involved in several of the most common cathode reactions during corrosion and can also cause embrittlement in many stainless steels. Some aspects of the effect of hydrogen on corrosion and hydrogen-induced stress cracking, HISC, of stainless steels were studied in this work. These aspects rel...

  1. Ultrasonic Impact Treatment to Improve Stress Corrosion Cracking Resistance of Welded Joints of Aluminum Alloy

    Science.gov (United States)

    Yu, J.; Gou, G.; Zhang, L.; Zhang, W.; Chen, H.; Yang, Y. P.

    2016-07-01

    Stress corrosion cracking is one of the major issues for welded joints of 6005A-T6 aluminum alloy in high-speed trains. High residual stress in the welded joints under corrosion results in stress corrosion cracking. Ultrasonic impact treatment was used to control the residual stress of the welded joints of 6005A-T6 aluminum alloy. Experimental tests show that ultrasonic impact treatment can induce compressive longitudinal and transverse residual stress in the welded joint, harden the surface, and increase the tensile strength of welded joints. Salt-fog corrosion tests were conducted for both an as-welded sample and an ultrasonic impact-treated sample. The surface of the treated sample had far fewer corrosion pits than that of the untreated sample. The treated sample has higher strength and lower tensile residual stress than the untreated sample during corrosion. Therefore, ultrasonic impact treatment is an effective technique to improve the stress corrosion cracking resistance of the welded joints of 6005A-T6 aluminum alloy.

  2. Stress corrosion cracking of welded Alloy 600 penetration mockups

    Energy Technology Data Exchange (ETDEWEB)

    Sarver, J.M. [Babcock and Wilcox, Alliance, OH (United States). Research and Development Div.; Pathania, R.S. [Electric Power Research Inst., Palo Alto, CA (United States); Stuckey, K.; Fyfitch, S. [B and W Nuclear Technologies, Lynchburg, VA (United States); Gelpi, A.; Foucault, M. [Framatome, Paris La Defense (France); Hunt, E.S. [Dominion Engineering, McLean, VA (United States)

    1995-12-31

    The primary water stress corrosion cracking (PWSCC) of Alloy 600 in components other than steam generators is a problem of increasing concern for nuclear power plants. Of greatest concern at the present time is the PWSCC of Alloy 600 vessel head penetrations. The common elements of these components are threefold: (1) the Alloy 600 material has a susceptible microstructure, (2) the Alloy 600 material is either a thick-walled tube or a bar which has been machined into a thick-walled tube, and (3) the Alloy 600 material has been welded into a structure such that high residual welding stresses exist in the postwelded Alloy 600 material. The objectives of the present program were to evaluate the PWSCC behavior of various configurations of welded Alloy 600 penetrations, and possible remedial measures which would prevent or retard PWSCC in these components. Mockups were instrumented to permit instantaneous remote sensing of through-wall cracking and were autoclave tested along with control C-rings in a doped steam environment. Following the test exposures, the mockups were split and examined to characterize the cracking morphology and the material microstructure. A Weibull distribution was used to analyze the time-to-failure results, and the observed cracking locations were compared to residual stress levels predicted by an elastic-plastic finite element analysis of the mockups.

  3. Stress corrosion cracking of NiTi in artificial saliva.

    Science.gov (United States)

    Wang, Jianqiu; Li, Nianxing; Rao, Guangbin; Han, En-Hou; Ke, Wei

    2007-02-01

    This paper aimed to study the mechanism of the cracking of orthodontic NiTi wire. Two orthodontic NiTi wires were subjected: (1) optical and scanning electron microscopy (SEM) to observe the fracture surface; (2) energy dispersive X-ray spectroscopy to determine the composition of the surface product; (3) anodic polarization to remove the surface product. Samples of NiTi alloy were subjected to the constant loading test to study the stress corrosion cracking (SCC) behavior of NiTi shape memory alloy in artificial saliva. The results showed that there were three typical areas at the fracture surface of NiTi orthodontic wire. Area '1' was a tool-made notch. Crack initiated from the root of this notch and propagated to form Area '2', which was perpendicular to the wire axis and covered by surface film. This film consisted of Na, K, Cl, P, S and O except Ni and Ti. The cracking process of NiTi alloy under the constant loading test depended on the pH of saliva and applied stress. The crack length was about 262microm, the longest at 300MPa and pH 3.0. A tool-made notch in orthodontic NiTi wires can cause SCC. At high stress and low pH, this NiTi alloy was most sensitive to cracking.

  4. An Investigation of Stress-Corrosion Cracking Susceptibility in Candidate Steels for Tension Leg Platform Tendons.

    Science.gov (United States)

    1986-04-24

    5773 An Investigation of Stress-Corrosion Cracking Susceptibility in Candidate Steels for Tension Leg Platform Tendons I. A. HAUSER II AND T. W. CROOKER...distribution unlimited. 4. PEfaOMIN 00GAZT1OM REPOT NIJMSER(S S. MONITORIN ORGAtsIZATIO61 REPWR NUMBEA(S NRL Memorandum Report 5773 Ga. NAME Of PFOROMIN...Fujil, "Stress-Corrosion Cracking Properties of 17-4 PH Steel", Stress Corrosion--New Approaches, ASTM STP 610, American Society for Testing and

  5. Irradiation-assisted stress corrosion cracking[1997 Scientific Report of the Belgian Nuclear Research Centre

    Energy Technology Data Exchange (ETDEWEB)

    Moons, F.

    1998-07-01

    The programme on corrosion at the Belgian Nuclear Research Centre SCK-CEN started in 1996 and focusses on modelling irradiation-assisted stress corrosion cracking and on developing in-pile electrochemical sensors and diagnostic equipment. The objective of this programme is to predict the behaviour of LWR core internals with respect to IASCC. Progress for 1997 is summarised.

  6. Stress-corrosion susceptibility of highway bridge construction steels. Phase I

    Science.gov (United States)

    1972-04-01

    A catalog of steels used in highway bridge construction has been developed. A state-of-the-art survey on the stress-corrosion susceptibility of these steels has been conducted. The types and concentrations of corrosives that can be experienced in the...

  7. 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

  8. 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.

  9. Stress corrosion cracking of an aluminum alloy used in external fixation devices.

    Science.gov (United States)

    Cartner, Jacob L; Haggard, Warren O; Ong, Joo L; Bumgardner, Joel D

    2008-08-01

    Treatment for compound and/or comminuted fractures is frequently accomplished via external fixation. To achieve stability, the compositions of external fixators generally include aluminum alloy components due to their high strength-to-weight ratios. These alloys are particularly susceptible to corrosion in chloride environments. There have been several clinical cases of fixator failure in which corrosion was cited as a potential mechanism. The aim of this study was to evaluate the effects of physiological environments on the corrosion susceptibility of aluminum 7075-T6, since it is used in orthopedic external fixation devices. Electrochemical corrosion curves and alternate immersion stress corrosion cracking tests indicated aluminum 7075-T6 is susceptible to corrosive attack when placed in physiological environments. Pit initiated stress corrosion cracking was the primary form of alloy corrosion, and subsequent fracture, in this study. Anodization of the alloy provided a protective layer, but also caused a decrease in passivity ranges. These data suggest that once the anodization layer is disrupted, accelerated corrosion processes occur. (c) 2007 Wiley Periodicals, Inc.

  10. 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

  11. [Chemical-microbiological diagnosis of stress-corrosive damage to pipelines

    Science.gov (United States)

    Kholodenko, V P; Zhigletsova, S K; Chugunov, V A; Rodin, V B; Kobelev, V S; Karpov, S V

    2000-01-01

    Samples of soil, ground, electrolyte, corrosion products, and protective coating were taken after excavating pipelines. The depth of stress corrosion cracks of the pipe steel was mostly related to the numbers of sulfate-reducing and denitrifying bacteria. In certain types of soil, damage correlated with the number of acid-producing microorganisms and aerobic chemoorganotrophs (saprophytes). A correlation was found between the extent of stress-corrosion damage to pipelines and the contents of reduced iron, sulfides, and organic carbon in surrounding ground.

  12. Stress Corrosion Cracking in Polymer Matrix Glass Fiber Composites

    Science.gov (United States)

    Kosak, Jonathan

    With the use of Polymer Matrix Glass Fiber Composites ever expanding, understanding conditions that lead to failure before expected service life is of increasing importance. Stress Corrosion Cracking (SCC) has proven to be one such example of conditions found in use in high voltage transmission line applications that leads to brittle fracture of polymer matrix composites. SCC has been proven to be the result of acid buildup on the lines due to corona discharges and water buildup. This acid leaches minerals from the fibers, leading to fracture at low loads and service life. In order to combat this problem, efforts are being made to determine which composites have greater resistance to SCC. This study was used to create a methodology to monitor for damage during SCC and classify damage by mechanism type (matrix cracking and fiber breaking) by using 4-point SCC bend testing, 3-point bend testing, a forward predictive model, unique post processing techniques, and microscopy. This would allow a classification in composite resistance to SCC as well as create a methodology for future research in this field. Concluding this study, only matrix cracking was able to be fully classified, however, a methodology was developed for future experimentation.

  13. Environmental stress-corrosion cracking of fiberglass: lessons learned from failures in the chemical industry.

    Science.gov (United States)

    Myers, T J; Kytömaa, H K; Smith, T R

    2007-04-11

    Fiberglass reinforced plastic (FRP) composite materials are often used to construct tanks, piping, scrubbers, beams, grating, and other components for use in corrosive environments. While FRP typically offers superior and cost effective corrosion resistance relative to other construction materials, the glass fibers traditionally used to provide the structural strength of the FRP can be susceptible to attack by the corrosive environment. The structural integrity of traditional FRP components in corrosive environments is usually dependent on the integrity of a corrosion-resistant barrier, such as a resin-rich layer containing corrosion resistant glass fibers. Without adequate protection, FRP components can fail under loads well below their design by an environmental stress-corrosion cracking (ESCC) mechanism when simultaneously exposed to mechanical stress and a corrosive chemical environment. Failure of these components can result in significant releases of hazardous substances into plants and the environment. In this paper, we present two case studies where fiberglass components failed due to ESCC at small chemical manufacturing facilities. As is often typical, the small chemical manufacturing facilities relied largely on FRP component suppliers to determine materials appropriate for the specific process environment and to repair damaged in-service components. We discuss the lessons learned from these incidents and precautions companies should take when interfacing with suppliers and other parties during the specification, design, construction, and repair of FRP components in order to prevent similar failures and chemical releases from occurring in the future.

  14. Environmental stress-corrosion cracking of fiberglass: Lessons learned from failures in the chemical industry

    Energy Technology Data Exchange (ETDEWEB)

    Myers, T.J. [Exponent Inc., 21 Strathmore Road, Natick, MA 01760 (United States)]. E-mail: tmyers@exponent.com; Kytoemaa, H.K. [Exponent Inc., 21 Strathmore Road, Natick, MA 01760 (United States); Smith, T.R. [Exponent Inc., 3401 Market Street, Suite 300, Philadelphia, PA 19104 (United States)

    2007-04-11

    Fiberglass reinforced plastic (FRP) composite materials are often used to construct tanks, piping, scrubbers, beams, grating, and other components for use in corrosive environments. While FRP typically offers superior and cost effective corrosion resistance relative to other construction materials, the glass fibers traditionally used to provide the structural strength of the FRP can be susceptible to attack by the corrosive environment. The structural integrity of traditional FRP components in corrosive environments is usually dependent on the integrity of a corrosion-resistant barrier, such as a resin-rich layer containing corrosion resistant glass fibers. Without adequate protection, FRP components can fail under loads well below their design by an environmental stress-corrosion cracking (ESCC) mechanism when simultaneously exposed to mechanical stress and a corrosive chemical environment. Failure of these components can result in significant releases of hazardous substances into plants and the environment. In this paper, we present two case studies where fiberglass components failed due to ESCC at small chemical manufacturing facilities. As is often typical, the small chemical manufacturing facilities relied largely on FRP component suppliers to determine materials appropriate for the specific process environment and to repair damaged in-service components. We discuss the lessons learned from these incidents and precautions companies should take when interfacing with suppliers and other parties during the specification, design, construction, and repair of FRP components in order to prevent similar failures and chemical releases from occurring in the future.

  15. Determination of Stress-Corrosion Cracking in Aluminum-Lithium Alloy ML377

    Science.gov (United States)

    Valek, Bryan C.

    1995-01-01

    The use of aluminum-lithium alloys for aerospace applications is currently being studied at NASA Langley Research Center's Metallic Materials Branch. The alloys in question will operate under stress in a corrosive environment. These conditions are ideal for the phenomena of Stress-Corrosion Cracking (SCC) to occur. The test procedure for SCC calls for alternate immersion and breaking load tests. These tests were optimized for the lab equipment and materials available in the Light Alloy lab. Al-Li alloy ML377 specimens were then subjected to alternate immersion and breaking load tests to determine residual strength and resistance to SCC. Corrosion morphology and microstructure were examined under magnification. Data shows that ML377 is highly resistant to stress-corrosion cracking.

  16. EFFECT OF INTERFACIAL STRUCTURE AND ENERGY ON CORROSION AND STRESS-CORROSION-CRACKING IN α Cu-Al ALLOY BICRYSTALS

    OpenAIRE

    Yamashita, M.; Mimaki, T.; Hashimoto, S.; Miura, S.

    1990-01-01

    Stabilities of the symmetrical - and -tilt and -twist boundaries of an α Cu-Al alloy against both dissolution and Stress-Corrosion-Cracking (SCC) are discussed. The susceptibilities of the boundaries to SCC are strongly dependent upon the misorientation. Cusps exist at some angles which are corresponding to relatively small Σ-values. These boundaries indicating great resistances to SCC also possess high stabilities against dissolution. It is considered that these high stabilities against both...

  17. FY17 Status Report: Research on Stress Corrosion Cracking of SNF Interim Storage Canisters.

    Energy Technology Data Exchange (ETDEWEB)

    Schindelholz, Eric John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bryan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Alexander, Christopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    This progress report describes work done in FY17 at Sandia National Laboratories (SNL) to assess the localized corrosion performance of container/cask materials used in the interim storage of spent nuclear fuel (SNF). Of particular concern is stress corrosion cracking (SCC), by which a through-wall crack could potentially form in a canister outer wall over time intervals that are shorter than possible dry storage times. Work in FY17 refined our understanding of the chemical and physical environment on canister surfaces, and evaluated the relationship between chemical and physical environment and the form and extent of corrosion that occurs. The SNL corrosion work focused predominantly on pitting corrosion, a necessary precursor for SCC, and process of pit-to-crack transition; it has been carried out in collaboration with university partners. SNL is collaborating with several university partners to investigate SCC crack growth experimentally, providing guidance for design and interpretation of experiments.

  18. Research on stress corrosion behavior of CCSE40 welded by underwater wet welding with austenitic welding rod in seawater

    Science.gov (United States)

    Zou, Y.; Bai, Q.; Dong, S.; Yang, Z. L.; Gao, Y.

    2017-09-01

    The stress corrosion behavior of CCSE40 welded by underwater wet welding with austenitic welding rod in seawater was studied. Microstructure, mechanical property and stress corrosion cracking susceptibility of the underwater wet welding joint were analyzed by metallographic observation, tensile and bending tests, slow strain rate test (SSRT) and SEM. The results indicated that the weld zone (WZ) and the heat affected zone (HAZ) were all sensitive to the stress corrosion, and the WZ was more sensitive than the HAZ.

  19. Mitigation of Stress Corrosion Cracking Susceptibility of Machined 304L Stainless Steel Through Laser Peening

    Science.gov (United States)

    Sundar, R.; Ganesh, P.; Kumar, B. Sunil; Gupta, R. K.; Nagpure, D. C.; Kaul, R.; Ranganathan, K.; Bindra, K. S.; Kain, V.; Oak, S. M.; Singh, Bijendra

    2016-09-01

    The paper describes an experimental study aimed at suppressing stress corrosion cracking susceptibility of machined 304L stainless steel specimens through laser shock peening. The study also evaluates a new approach of oblique laser shock peening to suppress stress corrosion cracking susceptibility of internal surface of type 304L stainless steel tube. The results of the study, performed with an indigenously developed 2.5 J/7 ns Nd:YAG laser, demonstrated that laser shock peening effectively suppresses chloride stress corrosion cracking susceptibility of machined surface of type 304L stainless steel. In the investigated range of incident laser power density (3.2-6.4 GW/cm2), machined specimens peened with power density of 4.5 and 6.4 GW/cm2 displayed lower stress corrosion cracking susceptibility considerably than those treated with 3.2 and 3.6 GW/cm2 in boiling magnesium chloride test. Oblique laser shock peening, performed on machined internal surface of a type 304L stainless steel tube (OD = 111 mm; ID = 101 mm), was successful in introducing residual compressive surface stresses which brought about significant suppression of its stress corrosion cracking susceptibility. The technique of oblique laser shock peening, in spite of its inherent limitations on the length of peened region being limited by tube internal diameter and the need for access from both the sides, presents a simplified approach for peening internal surface of small tubular components.

  20. 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.

  1. 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...

  2. 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.

  3. Study of scratch-induced stress corrosion cracking for steam generator tubes and scratch control

    Energy Technology Data Exchange (ETDEWEB)

    Meng, F.; Xu, X.; Liu, X. [Shanghai Nuclear Engineering Research and Design Institute, Shanghai (China); Wang, J. [Chinese Academy of Sciences, Institute of Metal Research, Shenyang (China)

    2014-07-01

    This paper introduces field cases for scratch-induced stress corrosion cracking (SISCC) of steam generator tubes in PWR and current studies in laboratories. According to analysis result of broke tubes, scratches caused intergranular stress corrosion cracking (IGSCC) with outburst. The effect of microstructure for nickel-base alloys, residual stresses caused by scratching process and water chemistry on SISCC and possible mechanism of SISCC are discussed. The result shows that scratch-induced microstructure evolution contributes to SISCC significantly. The causes of scratches during steam generator tubing manufacturing and installation process are stated and improved reliability with scratch control is highlighted for steam generator tubes in newly built nuclear power plants. (author)

  4. Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints

    Directory of Open Access Journals (Sweden)

    M. Vinoth Kumar

    2015-09-01

    Full Text Available Super 304H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of the material. Stress corrosion cracking susceptibility of Super 304H parent metal and gas tungsten arc (GTA welded joints were studied by constant load tests in 45% boiling MgCl2 solution. Stress corrosion cracking resistance of Super 304H stainless steel was deteriorated by GTA welding due to the formation of susceptible microstructure in the HAZ of the weld joint and the residual stresses. The mechanism of cracking was found to be anodic path cracking, with transgranular nature of crack propagation. Linear relationships were derived to predict the time to failure by extrapolating the rate of steady state elongation.

  5. The relative stress-corrosion-cracking susceptibility of candidate aluminum-lithium alloys for aerospace applications

    Science.gov (United States)

    Pizzo, P. P.

    1982-01-01

    Stress corrosion tests of Al-Li-Cu powder metallurgy alloys are described. Alloys investigated were Al-2.6% Li-1.4% and Al-2.6% Li-1.4% Cu-1.6% Mg. The base properties of the alloys were characterized. Process, heat treatment, and size/orientational effects on the tensile and fracture behavior were investigated. Metallurgical and electrochemical conditions are identified which provide reproducible and controlled parameters for stress corrosion evaluation. Preliminary stress corrosion test results are reported. Both Al-Li-Cu alloys appear more susceptible to stress corrosion crack initiation than 7075-T6 aluminum, with the magnesium bearing alloy being the most susceptible. Tests to determine the threshold stress intensity for the base and magnesium bearing alloys are underway. Twelve each, bolt loaded DCB type specimens are under test (120 days) and limited crack growth in these precracked specimens has been observed. General corrosion in the aqueous sodium chloride environment is thought to be obscuring results through crack tip blunting.

  6. Corrosion of metals exposed to 25% magnesium chloride solution and tensile stress: Field and laboratory studies

    Directory of Open Access Journals (Sweden)

    Xianming Shi

    2017-12-01

    Full Text Available The use of chemicals for snow and ice control operations is a common practice for improving the safety and mobility of roadways in cold climate, but brings significant concerns over their risks including the corrosive effects on transportation infrastructure and motor vehicles. The vast majority of existing studies and methods to test the deicer corrosivity have been restricted to laboratory environments and unstressed metals, which may not reliably simulate actual service conditions. As such, we report a case study in which stainless steel SS 304 (unstressed and externally tensile stressed, aluminum (Al 1100 and low carbon steel (C1010 coupons were exposed to 25% MgCl2 under field conditions for six weeks. A new corrosion test-bed was developed in Montana to accelerate the field exposure to this deicer. To further investigate the observed effect of tensile stress on the corrosion of stainless steel, SS 304 (unstressed and externally stressed coupons were exposed to 25% MgCl2 solution under the laboratory conditions. The C 1010 exhibited the highest percentage of rust area and suffered the most weight loss as a result of field exposure and MgCl2 sprays. In terms of ultimate tensile strength, the Al 1100 coupons saw the greatest reduction and the unstressed and externally stressed SS 304 coupons saw the least. The ability of MgCl2 to penetrate deep into the matrix of aluminum alloy poses great risk to such structural material. Tensile stressed SS 304 suffered more corrosion than unstressed SS 304 in both the field and laboratory conditions. Results from this case study may shed new light on the deicer corrosion issue and help develop improved field testing methods to evaluate the deicer corrosivity to metals in service.

  7. 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.

  8. Effect of exposure cycle on hot salt stress corrosion of a titanium alloy

    Science.gov (United States)

    Gray, H. R.; Johnston, J. R.

    1974-01-01

    The influence of exposure cycle on the hot-salt stress-corrosion cracking resistance of the Ti-8Al-1Mo-1V alloy was determined. Both temperature and stress were cycled simultaneously to simulate turbine-powered aircraft service cycles. Temperature and stress were also cycled independently to determine their individual effects. Substantial increases in crack threshold stresses were observed for cycles in which both temperature and stress or temperature alone were applied for 1 hour and removed for 3 hours. The crack threshold stresses for these cyclic exposures were twice those determined for continuous exposure for the same total time of 96 hours.

  9. The contribution of activated processes to Q. [stress corrosion cracking in seismic wave attenuation

    Science.gov (United States)

    Spetzler, H. A.; Getting, I. C.; Swanson, P. L.

    1980-01-01

    The possible role of activated processes in seismic attenuation is investigated. In this study, a solid is modeled by a parallel and series configuration of dashpots and springs. The contribution of stress and temperature activated processes to the long term dissipative behavior of this system is analyzed. Data from brittle rock deformation experiments suggest that one such process, stress corrosion cracking, may make a significant contribution to the attenuation factor, Q, especially for long period oscillations under significant tectonic stress.

  10. 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.

  11. Observations of intergranular stress corrosion cracking in a grain-mapped polycrystal.

    Science.gov (United States)

    King, A; Johnson, G; Engelberg, D; Ludwig, W; Marrow, J

    2008-07-18

    Nondestructive three-dimensional mapping of grain shape, crystallographic orientation, and grain boundary geometry by diffraction contrast tomography (DCT) provides opportunities for the study of the interaction between intergranular stress corrosion cracking and microstructure. A stress corrosion crack was grown through a volume of sensitized austenitic stainless steel mapped with DCT and observed in situ by synchrotron tomography. Several sensitization-resistant crack-bridging boundaries were identified, and although they have special geometric properties, they are not the twin variant boundaries usually maximized during grain boundary engineering.

  12. Influence of stress and phase on corrosion of a superelastic nickel-titanium orthodontic wire.

    Science.gov (United States)

    Segal, Nadav; Hell, Jess; Berzins, David W

    2009-06-01

    The purpose of this investigation was to study the effect of stress and phase transformation on the corrosion properties of a superelastic nickel-titanium orthodontic wire. The phase transformation profiles of superelastic nickel-titanium (Sentalloy, GAC International, Bohemia, NY) and beta-titanium (TMA, Ormco, Orange, Calif) archwires were analyzed by using differential scanning calorimetry. The force/deflection behavior of the wires at 37 degrees C was measured in a 3-point bending test per modified American Dental Association specification no. 32. Electrochemical testing consisted of monitoring the open circuit potential (OCP) for 2 hours followed by polarization resistance and cyclic polarization tests on archwire segments engaged in a 5-bracket simulation apparatus with bend deflections of 0.75, 1.5, or 3 mm in artificial saliva at 37 degrees C. Nondeflected segments were also tested. Sentalloy was additionally examined for bending and corrosion at 5 degrees C, where it exists as martensite and is devoid of stress-induced phase transformation. OCP at 2 hours and corrosion current density (i(corr)) were analyzed by using ANOVA and Tukey tests (alpha = .05) (n = 10 per deflection). Significant differences (P corrosion rate in nickel-titanium and beta-titanium orthodontic wires. Alterations in stress/strain associated with phase transformation in superelastic nickel-titanium might alter the corrosion rate in ways different from wires not undergoing phase transformation.

  13. In-vitro characterization of stress corrosion cracking of aluminium-free magnesium alloys for temporary bio-implant applications.

    Science.gov (United States)

    Choudhary, Lokesh; Singh Raman, R K; Hofstetter, Joelle; Uggowitzer, Peter J

    2014-09-01

    The complex interaction between physiological stresses and corrosive human body fluid may cause premature failure of metallic biomaterials due to the phenomenon of stress corrosion cracking. In this study, the susceptibility to stress corrosion cracking of biodegradable and aluminium-free magnesium alloys ZX50, WZ21 and WE43 was investigated by slow strain rate tensile testing in a simulated human body fluid. Slow strain rate tensile testing results indicated that each alloy was susceptible to stress corrosion cracking, and this was confirmed by fractographic features of transgranular and/or intergranular cracking. However, the variation in alloy susceptibility to stress corrosion cracking is explained on the basis of their electrochemical and microstructural characteristics. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Effect of residual stress induced by pulsed-laser irradiation on initiation of chloride stress corrosion cracking in stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Shuzo, E-mail: eto@criepi.denken.or.jp; Miura, Yasufumi; Tani, Junichi; Fujii, Takashi

    2014-01-10

    The atmospheric corrosion test and residual stress measurement were performed to evaluate the effect of laser irradiation on stress corrosion cracking (SCC) initiation. Second-harmonic Nd:YAG laser pulses (pulse width: 10 ns) were irradiated on a type-304L stainless-steel plate. The specimens were placed in a chamber at 353 K with RH=35% for the corrosion test. When laser energies were 30 and 300 mJ, cracks caused by SCC or pitting were observed on the surface of the specimens. The cracks were classified into two types on the basis of cumulative probability distribution; one of the types is related to the laser irradiation condition. The mean maximum crack depths were about 27 and 52 μm when laser energies were 30 and 300 mJ, respectively. These values were the same as the depth at which the tensile residual stress was induced from the surface of the specimen by laser irradiation. These results suggest that the maximum stress corrosion crack depth was caused by the tensile residual stress induced by laser irradiation, and that the crack stopped propagating when the crack depth was larger than several dozen μm in this test set. When laser pulses of 300 mJ energy were irradiated on the surface of the specimen by shot peening, the tensile stress was induced up to 20 μm from the surface, and the compressive stress was observed at a larger depth. These results show that the laser irradiation is less effective in obtaining tensile residual stress of the specimen compared to when laser pulses are irradiated on the specimen treated by shot peening. The depth of tensile stress obtained by laser irradiation is much shorter than that of compressive stress obtained by shot peening.

  15. 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.

  16. SEM observations on stress corrosion cracking of commercially pure titanium in a topical fluoride solution.

    Science.gov (United States)

    Könönen, M H; Lavonius, E T; Kivilahti, J K

    1995-07-01

    OBJECTIVES. The purpose of the present study was to determine whether commercially pure titanium is susceptible to stress corrosion cracking/hydrogen embrittlement in a topical fluoride solution used in preventive dentistry. Thin electropolished titanium test specimens were previously cold-rolled or cold-rolled and annealed before testing. For the stress corrosion tests, the U-shaped specimens of both treatment types were stressed into a radius of curvature of 30 mm. Then, the bent part was placed in the fluoride solution at 37 degrees C for 1, 5, 10, and 20 d. The effects of the fluoride solution on cold-rolled and annealed titanium were studied using a scanning electron microscope. In addition, mechanically fractured surfaces of cold-rolled titanium specimens exposed and not exposed to the fluoride solution were examined by SEM. A qualitative evaluation of the surfaces was conducted. Narrow cracks were observed in cold-rolled specimens following exposure to the fluoride solution for 5 d. The cracks were associated with branching, a characteristic of stress corrosion cracking. The cold-rolled specimen exposed to the fluoride solution exhibited a brittle fracture. In contrast, the fracture mode of the unexposed specimen was ductile in nature. Topical fluoride solutions can cause stress corrosion cracking of commercially pure titanium.

  17. Fatigue failure in polysilicon not due to simple stress corrosion cracking.

    Science.gov (United States)

    Kahn, H; Ballarini, R; Bellante, J J; Heuer, A H

    2002-11-08

    In the absence of a corrosive environment, brittle materials such as silicon should be immune to cyclic fatigue. However, fatigue effects are well known in micrometer-sized polycrystalline silicon (polysilicon) samples tested in air. To investigate the origins of this phenomenon in polysilicon, we developed a fixed-grip fracture mechanics microspecimen but could find no evidence of static stress corrosion cracking. The environmental sensitivity of the fatigue resistance was also investigated under cyclic loading. For low-cycle fatigue, the behavior is independent of the ambient conditions, whether air or vacuum, but is strongly influenced by the ratio of compressive to tensile stresses experienced during each cycle. The fatigue damage most likely originates from contact stresses at processing-related surface asperities; subcritical crack growth then ensues during further cyclic loading. The lower far-field stresses involved in high-cycle fatigue induce reduced levels of fatigue damage. Under these conditions, a corrosive ambient such as laboratory air exacerbates the fatigue process. Without cyclic loading, polysilicon does not undergo stress corrosion cracking.

  18. Standard Practice for Making and Using U-Bend Stress-Corrosion Test Specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice covers procedures for making and using U-bend specimens for the evaluation of stress-corrosion cracking in metals. The U-bend specimen is generally a rectangular strip which is bent 180° around a predetermined radius and maintained in this constant strain condition during the stress-corrosion test. Bends slightly less than or greater than 180° are sometimes used. Typical U-bend configurations showing several different methods of maintaining the applied stress are shown in Fig. 1. 1.2 U-bend specimens usually contain both elastic and plastic strain. In some cases (for example, very thin sheet or small diameter wire) it is possible to form a U-bend and produce only elastic strain. However, bent-beam (Practice G 39 or direct tension (Practice G 49)) specimens are normally used to study stress-corrosion cracking of strip or sheet under elastic strain only. 1.3 This practice is concerned only with the test specimen and not the environmental aspects of stress-corrosion testing which are discus...

  19. Effects of laser shock peening on stress corrosion behavior of 7075 aluminum alloy laser welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.T., E-mail: jiasqq1225@126.com [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Zhang, Y.K. [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Mechanical Engineering, Southeast University, Nanjing 211189 (China); Chen, J.F.; Zhou, J.Y.; Ge, M.Z.; Lu, Y.L.; Li, X.L. [School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001 (China)

    2015-10-28

    7075 aluminum alloy weldments were processed by an intensive process known as laser shock peening (LSP), meanwhile its stress corrosion behaviors were observed by scanning electron microscopy (SEM) and slow strain rate tensile (SSRT) tests. Results showed that the effect of LSP on corrosion behavior of the joint was fairly useful and obvious. With LSP, the elongation, time of fracture and static toughness after the SSRT test were improved by 11.13%, 20% and 100%, respectively. At the same time, the location of the fracture also changed. LSP led to a transition of the fracture type from transgranular to intergranular The reasons for these enhancements of the joint on corrosion behavior were caused by microstructure, residual stress, micro-hardness, and fracture appearance.

  20. Stress Corrosion Cracking Behavior of X80 Pipeline Steel in Acid Soil Environment with SRB

    Science.gov (United States)

    Wang, Dan; Xie, Fei; Wu, Ming; Liu, Guangxin; Zong, Yue; Li, Xue

    2017-06-01

    Self-designed experimental device was adopted to ensure the normal growth of sulphate-reducing bacteria (SRB) in sterile simulated Yingtan soil solution. Stress corrosion cracking (SCC) behavior of X80 pipeline steel in simulated acid soil environment was investigated by electrochemical impedance spectroscopy, slow strain rate test, and scanning electron microscope. Results show that the presence of SRB could promote stress corrosion cracking susceptibility. In a growth cycle, polarization resistance first presents a decrease and subsequently an increase, which is inversely proportional to the quantities of SRB. At 8 days of growth, SRB reach their largest quantity of 1.42 × 103 cells/g. The corrosion behavior is most serious at this time point, and the SCC mechanism is hydrogen embrittlement. In other SRB growth stages, the SCC mechanism of X80 steel is anodic dissolution. With the increasing SRB quantities, X80 steel is largely prone to SCC behavior, and the effect of hydrogen is considerably obvious.

  1. Influence of oxide films on primary water stress corrosion cracking initiation of alloy 600

    Energy Technology Data Exchange (ETDEWEB)

    Panter, J. [Framatome, Centre Technique, BP 181, 71205 Le Creusot cedex (France); Viguier, B. [Centre Inter-Universitaire de Recherche et d' Ingenierie des Materiaux (CIRIMAT), CNRS/INPT/UPS, ENSIACET, 118 Route de Narbonne, 31077 Toulouse cedex 04 (France)]. E-mail: Bernard.Viguier@ensiacet.fr; Cloue, J.-M. [Framatome, Centre Technique, BP 181, 71205 Le Creusot cedex (France); Foucault, M. [Framatome, Centre Technique, BP 181, 71205 Le Creusot cedex (France); Combrade, P. [Framatome, Centre Technique, BP 181, 71205 Le Creusot cedex (France); Andrieu, E. [Centre Inter-Universitaire de Recherche et d' Ingenierie des Materiaux (CIRIMAT), CNRS/INPT/UPS, ENSIACET, 118 Route de Narbonne, 31077 Toulouse cedex 04 (France)

    2006-01-01

    In the present study alloy 600 was tested in simulated pressurised water reactor (PWR) primary water, at 360 deg. C, under an hydrogen partial pressure of 30 kPa. These testing conditions correspond to the maximum sensitivity of alloy 600 to crack initiation. The resulting oxidised structures (corrosion scale and underlying metal) were characterised. A chromium rich oxide layer was revealed, the underlying metal being chromium depleted. In addition, analysis of the chemical composition of the metal close to the oxide scale had allowed to detect oxygen under the oxide scale and particularly in a triple grain boundary. Implication of such a finding on the crack initiation of alloy 600 is discussed. Significant diminution of the crack initiation time was observed for sample oxidised before stress corrosion tests. In view of these results, a mechanism for stress corrosion crack initiation of alloy 600 in PWR primary water was proposed.

  2. Influence of oxide films on primary water stress corrosion cracking initiation of alloy 600

    Science.gov (United States)

    Panter, J.; Viguier, B.; Cloué, J.-M.; Foucault, M.; Combrade, P.; Andrieu, E.

    2006-01-01

    In the present study alloy 600 was tested in simulated pressurised water reactor (PWR) primary water, at 360 °C, under an hydrogen partial pressure of 30 kPa. These testing conditions correspond to the maximum sensitivity of alloy 600 to crack initiation. The resulting oxidised structures (corrosion scale and underlying metal) were characterised. A chromium rich oxide layer was revealed, the underlying metal being chromium depleted. In addition, analysis of the chemical composition of the metal close to the oxide scale had allowed to detect oxygen under the oxide scale and particularly in a triple grain boundary. Implication of such a finding on the crack initiation of alloy 600 is discussed. Significant diminution of the crack initiation time was observed for sample oxidised before stress corrosion tests. In view of these results, a mechanism for stress corrosion crack initiation of alloy 600 in PWR primary water was proposed.

  3. Circumferential Notched Tensile Testing for Correlation of the Stress Intensity Factor ( K I ) and Stress Corrosion Crack Growth Rate

    Science.gov (United States)

    Rihan, R.; Singh Raman, R. K.; Ibrahim, R. N.

    2008-07-01

    A novel fracture mechanics technique has been employed for the determination of crack growth rate and threshold stress intensity factor ( K ISCC) for stress corrosion cracking (SCC) using small circumferential notch tensile (CNT) specimens. The technique was applied successfully for testing SCC susceptibility of AISI 1020 mild steel in 12.5 M NaOH at 150 °C. The crack growth rate of mild steel in 12.5 M NaOH solution at 150 °C has been determined at different stress intensity factors ( K I ), and the K ISCC has been determined to be 29 MPa·m1/2. The surfaces of fractured specimens have been examined by scanning electron microscopy (SEM) in order to establish intergranular propagation of stress corrosion cracks. The CNT testing is a simple, relatively fast, and cost-advantageous approach for generating crack growth rate and K ISCC data.

  4. Overlapping double etch technique for evaluation of metallic alloys to stress corrosion cracking

    Science.gov (United States)

    Not Available

    1980-05-28

    A double overlapping etch zone technique for evaluation of the resistance of metallic alloys to stress corrosion cracking is described. The technique involves evaluating the metallic alloy along the line of demarcation between an overlapping double etch zone and single etch zone formed on the metallic alloy surface.

  5. Overlapping double etch technique for evaluation of metallic alloys to stress corrosion cracking

    Science.gov (United States)

    Steeves, Arthur F.; Stewart, James C.

    1981-01-01

    A double overlapping etch zone technique for evaluation of the resistance of metallic alloys to stress corrosion cracking. The technique involves evaluating the metallic alloy along the line of demarcation between an overlapping double etch zone and single etch zone formed on the metallic alloy surface.

  6. Is the early fragmentation of intrauterine devices caused by stress corrosion cracking?

    Science.gov (United States)

    Pereda, M D; Farina, S B; Fernández Lorenzo, M

    2009-10-01

    Copper wire is the main component of a type of intrauterine device used as a contraceptive. Its contraceptive effect is attributed to the copper ions released as a result of the dissolution of copper in the uterus. Even though 10-year intrauterine device life is estimated on the basis of the dissolution rate of copper measured in vivo and in vitro, some cases of breakdown or fragmentation of the copper wire after short periods of insertion (2-3 months) have been reported. Due to the possible existence of residual stresses as a consequence of the manufacturing process, stress corrosion cracking has been previously proposed as an explanation for the early ruptures. In the present work, the susceptibility of copper wires to stress corrosion cracking in simulated uterine fluids was investigated. Results indicate that early ruptures should not be attributed to stress corrosion cracking. They could be explained by considering the increase in corrosion rate under certain conditions (pH decrease during infections; changes in the concentration of organic components along the menstrual cycle; etc.) that reduces the wire section leading to the rupture of the specimen by overloading.

  7. The stress corrosion resistance and the cryogenic temperature mechanical properties of annealed Nitronic 60 bar material

    Science.gov (United States)

    Montano, J. W. L.

    1977-01-01

    Ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of annealed, straightened, and centerless ground Nitronic 60 stainless steel alloy bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing strength with decreasing temperature to -196 C. Below liquid nitrogen temperature the smooth tensile and notched tensile strengths decreased slightly while the elongation and reduction of area decreased drastically. The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens and transverse C-ring specimens exposed to: alternate immersion in a 3.5% NaCl bath; humidity cabinet; and a 5% salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack. Approximately 3/4 of the transverse C-rings exposed to alternate immersion and to salt spray experienced a pitting attack on the top and bottom ends. Additional stress corrosion tests were performed on transverse tensile specimens. No failures occurred in the 90% stressed specimens exposed for 90 days in the alternate immersion and salt spray environments

  8. 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

  9. Stress Corrosion Cracking of Steel and Aluminum in Sodium Hydroxide: Field Failure and Laboratory Test

    Directory of Open Access Journals (Sweden)

    Y. Prawoto

    2012-01-01

    Full Text Available Through an investigation of the field failure analysis and laboratory experiment, a study on (stress corrosion cracking SCC behavior of steel and aluminum was performed. All samples were extracted from known operating conditions from the field failures. Similar but accelerated laboratory test was subsequently conducted in such a way as to mimic the field failures. The crack depth and behavior of the SCC were then analyzed after the laboratory test and the mechanism of stress corrosion cracking was studied. The results show that for the same given stress relative to ultimate tensile strength, the susceptibility to SCC is greatly influenced by heat treatment. Furthermore, it was also concluded that when expressed relative to the (ultimate tensile strength UTS, aluminum has similar level of SCC susceptibility to that of steel, although with respect to the same absolute value of applied stress, aluminum is more susceptible to SCC in sodium hydroxide environment than steel.

  10. Pressure effects on the hot-salt stress-corrosion cracking of titanium alloys

    OpenAIRE

    Chevrot, Thierry

    1994-01-01

    Benefiting from good specific mechanical properties, exceptional oxidation resistance, and high temperature capability, Titanium Alloys are used in Gas Turbine Engines, especially in the early stages of the compressor. However they are subject to stresscorrosion cracking in the laboratory when subjected to stresses and contaminated with salts at elevated temperatures. The lack of in-service failures of titanium components due to Hot-Salt Stress-Corrosion Cracking (HSSCC) is not...

  11. 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

    2017-05-01

    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. Copyright © 2017. Published by Elsevier B.V.

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

    Science.gov (United States)

    Singh Raman, R. K.; Siew, Wai Hoong

    2014-01-01

    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. PMID:28788276

  13. 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.

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

    Science.gov (United States)

    Raman, R K Singh; Siew, Wai Hoong

    2014-12-05

    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.

  15. Effects of Ultrasonic Nanocrystal Surface Modification on the Residual Stress, Microstructure, and Corrosion Resistance of 304 Stainless Steel Welds

    Science.gov (United States)

    Ye, Chang; Telang, Abhishek; Gill, Amrinder; Wen, Xingshuo; Mannava, Seetha R.; Qian, Dong; Vasudevan, Vijay K.

    2018-01-01

    In this study, ultrasonic nanocrystal surface modification (UNSM) of 304 stainless steel welds was carried out. UNSM effectively eliminates the tensile stress generated during welding and imparts beneficial compressive residual stresses. In addition, UNSM can effectively refine the grains and increase hardness in the near-surface region. Corrosion tests in boiling MgCl2 solution demonstrate that UNSM can significantly improve the corrosion resistance due to the compressive residual stresses and changes in the near-surface microstructure.

  16. Stress corrosion cracking of high-strength AZ31 processed by high-ratio differential speed rolling

    Directory of Open Access Journals (Sweden)

    Zhiming Shi

    2015-12-01

    Full Text Available Stress corrosion cracking (SCC in distilled water was studied for AZ31, processed by differential-speed-rolling to different strengths, using Linear Increasing Stress Tests (LISTs. The stress corrosion crack velocity was 5.0 ± 2.5 × 10−9 m s−1, independent of applied stress rate and independent of material strength. SCC susceptibility was greater at lower applied stress rates manifest most importantly as a lower threshold stress for stress corrosion crack initiation. SCC susceptibility could be characterised by the ratio of threshold stress to yield stress, which was dependent on processing details and was as low as 0.3.

  17. 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.

  18. 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.

  19. Diffusion-coupled cohesive interface simulations of stress corrosion intergranular cracking in polycrystalline materials

    Energy Technology Data Exchange (ETDEWEB)

    Pu, Chao; Gao, Yanfei; Wang, Yanli; Sham, T. -L.

    2017-09-01

    To study the stress corrosion intergranular cracking mechanism, a diffusion-coupled cohesive zone model (CZM) is proposed for the simulation of the stress-assisted diffusional process along grain boundaries and the mechanical response of grain boundary sliding and separation. This simulation methodology considers the synergistic effects of impurity diffusion driven by pressure gradient and degradation of grain boundary strength by impurity concentration. The diffusion-coupled CZM is combined with crystal plasticity finite element model (CPFEM) to simulate intergranular fracture of polycrystalline material under corrosive environment. Significant heterogeneity of the stress field and extensive impurity accumulation is observed at grain boundaries and junction points. Deformation mechanism maps are constructed with respect to the grain boundary degradation factor and applied strain rate, which dictate the transition from internal to near-surface intergranular fracture modes under various strain amplitudes and grain sizes.

  20. A mechanical property and stress corrosion evaluation of 431 stainless steel alloy

    Science.gov (United States)

    Montano, J. W.

    1973-01-01

    The mechanical properties of type 431 stainless steel in two conditions: annealed bar and hardened and tempered bar are presented. Test specimens, manufactured from approximately 1.0 inch (2.54 cm) diameter bar stock, were tested at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C). The test data indicated excellent tensile strength, notched/unnotched tensile ratio, ductility, shear, and impact properties at all testing temperatures. Results of the alternate immersion stress corrosion tests on stressed and unstressed longitudinal tensile specimens 0.1250 inch (0.3175 cm) diameter and transverse C-ring specimens, machined from 1.0 inch (2.54 cm) diameter bar stock, indicated that the material is not susceptible to stress corrosion cracking when tested in a 3.5 percent NaCl solution for 180 days.

  1. Standard practice for making and using precracked double beam stress corrosion specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This practice covers procedures for fabricating, preparing, and using precracked double beam stress corrosion test specimens. This specimen configuration was formerly designated the double cantilever beam (DCB) specimen. Guidelines are given for methods of exposure and inspection. 1.2 The precracked double beam specimen, as described in this practice, is applicable for evaluation of a wide variety of metals exposed to corrosive environments. It is particularly suited to evaluation of products having a highly directional grain structure, such as rolled plate, forgings, and extrusions, when stressed in the short transverse direction. 1.3 The precracked double beam specimen may be stressed in constant displacement by bolt or wedge loading or in constant load by use of proof rings or dead weight loading. The precracked double beam specimen is amenable to exposure to aqueous or other liquid solutions by specimen immersion or by periodic dropwise addition of solution to the crack tip, or exposure to the atmos...

  2. 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.

  3. Stress Corrosion Behavior of Low-temperature Liquid-Nitrided 316 Austenitic Stainless Steel in a Sour Environment

    Science.gov (United States)

    Zhang, Xiangfeng; Wang, Jun; Fan, Hongyuan; Yan, Jing; Duan, Lian; Gu, Tan; Xian, Guang; Sun, Lan; Wang, Danqi

    2017-10-01

    Low-temperature nitridation is a widely used surface heat treatment. Low-temperature liquid nitridation was applied to 316 austenitic stainless steel and an S-phase (expanded austenite) layer was achieved on the alloy surface. The effect of the S-phase layer on corrosion resistance and stress corrosion cracking was investigated in a sour environment. When a bending stress of 164 MPa (80 pct yield stress, YS) was applied, no macroscopic corrosion cracking and pits were observed on the nitrided samples and the S-phase layer stayed intact. Although no macroscopic corrosion cracking was observed on the non-nitrided samples under 205 MPa (100 pct YS), some pits were formed on the alloy surface. This could be attributed to the high stresses and hardness, and the excellent corrosion resistance of the S-phase layer introduced by low-temperature nitridation. Supersaturated nitrogen atoms in the S-phase layer can effectively prevent the decrease in pH of the corrosive medium and accelerate the alloy repassivation kinetics. However, when the bending stress was increased to 205 and 246 MPa (100 pct YS, 120 pct YS), macroscopic cracks were observed in the presence of both tensile stress and a corrosive medium.

  4. Stress Corrosion Behavior of Low-temperature Liquid-Nitrided 316 Austenitic Stainless Steel in a Sour Environment

    Science.gov (United States)

    Zhang, Xiangfeng; Wang, Jun; Fan, Hongyuan; Yan, Jing; Duan, Lian; Gu, Tan; Xian, Guang; Sun, Lan; Wang, Danqi

    2018-01-01

    Low-temperature nitridation is a widely used surface heat treatment. Low-temperature liquid nitridation was applied to 316 austenitic stainless steel and an S-phase (expanded austenite) layer was achieved on the alloy surface. The effect of the S-phase layer on corrosion resistance and stress corrosion cracking was investigated in a sour environment. When a bending stress of 164 MPa (80 pct yield stress, YS) was applied, no macroscopic corrosion cracking and pits were observed on the nitrided samples and the S-phase layer stayed intact. Although no macroscopic corrosion cracking was observed on the non-nitrided samples under 205 MPa (100 pct YS), some pits were formed on the alloy surface. This could be attributed to the high stresses and hardness, and the excellent corrosion resistance of the S-phase layer introduced by low-temperature nitridation. Supersaturated nitrogen atoms in the S-phase layer can effectively prevent the decrease in pH of the corrosive medium and accelerate the alloy repassivation kinetics. However, when the bending stress was increased to 205 and 246 MPa (100 pct YS, 120 pct YS), macroscopic cracks were observed in the presence of both tensile stress and a corrosive medium.

  5. A Parameter Sensitivity Analysis of the Effect of Rebar Corrosion on the Stress Field in the Surrounding Concrete

    Directory of Open Access Journals (Sweden)

    Fangyuan Li

    2017-01-01

    Full Text Available Rebar corrosion results in a change in the stress field in the surrounding concrete, which in turn accelerates the deterioration of the concrete structure. In addition to the protective layer, the compressive stress under which concrete is prestressed also affects the effect of corrosion-induced rebar expansion on the stress field in the concrete. The present study simulates the effect of corrosion-induced rebar expansion on the stress field in the concrete using the finite element method (FEM by applying a virtual radial displacement to the product of corrosion-induced rebar expansion. Based on an analysis of the effect of multiple rebars on the stress field in ordinary concrete, stress distribution in the protective layer of the concrete is determined. Afterward, the locations where there is damage to the surface concrete caused by rebar corrosion are determined. After verifying the feasibility of the FEM analysis, the effect of corrosion-induced ordinary rebar expansion in a typical prestressed concrete segment is determined by analyzing the characteristics of corrosion-induced rebar expansion occurring in various prestressed concrete specimens.

  6. SR-Site - sulphide content in the groundwater at Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Tullborg, E-L (Terralogica (Sweden)); Smellie, J (Conterra (Sweden)); Nilsson, A-Ch (Geosigma (Sweden)); Gimeno, M J; Auque, LF (Univ. of Zaragoza (Spain)); Bruchert, V (Stockholms Universitet (Sweden)); Molinero, J (Amphos21 (Spain))

    2010-12-15

    Sulphide concentrations in groundwater play a key role in the long-term reliability of the metal canisters containing the radioactive waste within a disposal facility for nuclear waste. This is because sulphide in the groundwaters circulating in the vicinity of the deposition tunnels can react with copper in the canisters causing corrosion and therefore reducing their expected lifetime; in a worst case scenario erosion of the bentonite buffer material will expose the canister more rapidly to the fracture groundwater.Sulphide in the groundwater is predominantly microbially produced and thereby controlled by the content of oxidised sulphur sources, organics (carbon sources), reductants (mainly Fe(II), DOC, H{sub 2} and CH{sub 4}), and also flow and mixing of different groundwater types. In addition, achieved saturation in respect to amorphous Fe-monosulphide will control the possible maximum values and will also limit the Fe2+ and S2- values in the groundwater. The aim of this report is to assess realistic, representative and reliable sulphide groundwater concentrations at present conditions in Forsmark and also to evaluate possible changes during different climatic conditions covering the repository operation period (some tens to hundreds of years), post closure conditions (some thousand of years) and the proceeding temperate period (some tens of thousands of years) which may be extended due to enhanced greenhouse effects etc. It is expected that this period will be followed by the onset of the next glaciation during which periglacial (permafrost), glacial and postglacial conditions may succeed each other. To achieve these aims, an evaluation is performed of all the sulphide-related data reported from the Forsmark site investigations /Laaksoharju et al. 2008/ and later monitoring campaigns, all of which are stored in the Sicada database. This evaluation shows that values from the Complete Chemical Characterisation (CCC) sampling are usually lower than those measured

  7. Corrosion behaviour of alloy 31 - UNS N08031 - under conditions of oil and gas production

    Energy Technology Data Exchange (ETDEWEB)

    Kloewer, J. [ThyssenKrupp VDM France SARL, Rueil-Malmaison (France); Schlerkmann, H.; Poepperling, R. [Mannesmann Forschungsinstitut, Duisburg (Germany)

    2002-10-01

    The corrosion behaviour of alloy 31 (UNS N08031-31Ni-27Cr-6.5Mo-1.2Cu-0.2N-bal.Fe) was tested in laboratory and field tests in seawater with and without additions of CO{sub 2} and/or H{sub 2}S in slow strain rate tests, and in SSC (Sulphide Stress Corrosion) tests according to NACE MR0175. The results demonstrate a high resistance of alloy 31 to localised corrosion. Due to the high chromium and molybdenum concentration, its resistance to pitting and crevice corrosion in chloride-contaminated seawater is significantly higher than that of alloy 28 and alloy 825 and it equals that of typical nickel base alloys like alloy 625. Alloy 31 is not sensitive to chloride-induced stress corrosion cracking, either with or without H{sub 2}S, or sulphide stress cracking. Alloy 31 is approved for sour gas applications up to LEVEL VI in NACE MR0175. The combination of properties makes alloy 31 an attractive choice for components in oil and gas production including wirelines, umbilicals, tubing, piping and topside application. (orig.)

  8. Aqueous stress-corrosion cracking of high-toughness D6AC steel

    Science.gov (United States)

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

    1976-01-01

    The crack growth behavior of D6AC steel as a function of stress intensity, stress and corrosion history, and test technique, under sustained load in filtered natural seawater, 3.3 per cent sodium chloride solution, and distilled water, was investigated. Reported investigations of D6AC were considered in terms of the present study with emphasis on thermal treatment, specimen configuration, fracture toughness, crack-growth rates, initiation period, and threshold. Both threshold and growth kinetics were found to be relatively insensitive to these test parameters. The apparent incubation period was dependent on technique, both detection sensitivity and precracking stress intensity level.

  9. 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.

  10. 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.

  11. 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

  12. Effect of Superficial Atmospheric Corrosion Upon the Internal Stresses in Structural Steel Elements

    Directory of Open Access Journals (Sweden)

    Monel Leiba

    2006-01-01

    Full Text Available A research program is presented showing the stress status determined by the corrosion phenomenon inside a specimen of a structural steel element. Several stains are studied their diameters ranging from 1~mm to 6~mm and thickness of the corroded layer under 0.5~mm. The physical modeling is the result of testing in laboratory the phenomenon of superficial atmospheric corrosion and the numerical modeling was developed under a FEM program, ALGOR. A number of 3,200 finite elements of BRICK type were created and the evolution of normal and tangential stresses was scrutinized under the process of loosing elementary material transformed into scrap. Stresses in the damaged sphere were graphically put into evidence and determined with accuracy due to the performances of the program, showing the local perturbations and the pattern of stress concentrators. The studies showed the importance of reproducing with both physical and mathematical methods the intricate mechanism and sometimes unpredictable effects of corrosion phenomenon upon the structural steel elements.

  13. 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

  14. Stress Corrosion Evaluation of Nitinol 60 for the International Space Station Water Recycling System

    Science.gov (United States)

    Torres, P. D.

    2016-01-01

    A stress corrosion cracking (SCC) evaluation of Nitinol 60 was performed because this alloy is considered a candidate bearing material for the Environmental Control and Life Support System (ECLSS), specifically in the Urine Processing Assembly of the International Space Station. An SCC evaluation that preceded this one during the 2013-2014 timeframe included various alloys: Inconel 625, Hastelloy C-276, titanium (Ti) commercially pure (CP), Ti 6Al-4V, extra-low interstitial (ELI) Ti 6Al-4V, and Cronidur 30. In that evaluation, most specimens were exposed for a year. The results of that evaluation were published in NASA/TM-2015-218206, entitled "Stress Corrosion Evaluation of Various Metallic Materials for the International Space Station Water Recycling System,"1 available at the NASA Scientific and Technical Information program web page: http://www.sti.nasa.gov. Nitinol 60 was added to the test program in 2014.

  15. Aqueous chloride stress corrosion cracking of titanium - A comparison with environmental hydrogen embrittlement

    Science.gov (United States)

    Nelson, H. G.

    1974-01-01

    The physical characteristics of stress corrosion cracking of titanium in an aqueous chloride environment are compared with those of embrittlement of titanium by a gaseous hydrogen environment in an effort to help contribute to the understanding of the possible role of hydrogen in the complex stress corrosion cracking process. Based on previous studies, the two forms of embrittlement are shown to be similar at low hydrogen pressures (100 N/sq m) but dissimilar at higher hydrogen pressures. In an effort to quantify this comparison, tests were conducted in an aqueous chloride solution using the same material and test techniques as had previously been employed in a gaseous hydrogen environment. The results of these tests strongly support models based on hydrogen as the embrittling species in an aqueous chloride environment.

  16. Stress corrosion cracking resistance of aluminum alloy 7000 series after two-step aging

    Directory of Open Access Journals (Sweden)

    Jegdić Bore V.

    2015-01-01

    Full Text Available The effect of one step-and a new (short two-step aging on the resistance to stress corrosion cracking of an aluminum alloy 7000 series was investigated, using slow strain rate test and fracture mechanics method. Aging level in the tested alloy was evaluated by means of scanning electron microscopy and measurements of electrical resistivity. It was shown that the alloy after the new two-step aging is significantly more resistant to stress corrosion cracking. Values of tensile properties and fracture toughness are similar for both thermal states. Processes that take place at the crack tip have been considered. The effect of the testing solution temperature on the crack growth rate on the plateau was determined. Two values of the apparent activation energy were obtained. These values correspond to different processes that control crack growth rate on the plateau at higher and lower temperatures. [Projekat Ministarstva nauke Republike Srbije, br. TR 34028 i br. TR 34016

  17. Effects of Grain Boundary Morphologies on Stress Corrosion Cracking of Alloy 600

    Directory of Open Access Journals (Sweden)

    Kim H.P.

    2017-06-01

    Full Text Available Effects of grain boundary morphologies on stress corrosion cracking (SCC of Alloy 600 have been studied in 40% NaOH at 315°C using C-ring specimens. The configuration of the grain boundary and the intergranular carbide density were controlled by heat treatment. SCC tests were performed at +150 mV above the corrosion potential. The specimen with a serrated grain boundary showed higher SCC resistance than that with a straight grain boundary. This appears to be caused by the fact that the specimen with the serrated grain boundary has longer SCC path. SCC resistance also increased with intergranular carbide density probably due to enhanced relaxation of stress at intergranular carbide.

  18. Standard practice for preparation and use of direct tension stress-corrosion test specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1985-01-01

    1.1 This practice covers procedures for designing, preparing, and using ASTM standard tension test specimens for investigating susceptibility to stress-corrosion cracking. Axially loaded specimens may be stressed quantitatively with equipment for application of either a constant load, constant strain, or with a continuously increasing strain. 1.2 Tension test specimens are adaptable for testing a wide variety of product forms as well as parts joined by welding, riveting, or various other methods. 1.3 The exposure of specimens in a corrosive environment is treated only briefly because other standards are being prepared to deal with this aspect. Meanwhile, the investigator is referred to Practices G35, G36, G37, and G44, and to ASTM Special Technical Publication 425 (1).

  19. 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

  20. The Effect of Applied Tensile Stress on Localized Corrosion in Sensitized AA5083

    Science.gov (United States)

    2015-09-01

    Littoral Combat Ships (LCS, using AA5083-H116). One area of research is on the welding processes used for aluminum alloys, including friction stir... welding (FSW) and gas metal arc welding (GMAW) [6]. Though these welding techniques can improve the manufacturing and repair products for aluminum alloys...corrosion issues. Welding causes microstructural changes to the base metal and creates residual longitudinal and transverse stresses, both of which

  1. 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.

  2. Study of the Effect of Swelling on Irradiation Assisted Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-01

    This report describes the methodology used to study the effect of swelling on the crack growth rate of an irradiation-assisted stress corrosion crack that is propagating in highly irradiated stainless steel 304 material irradiated to 33 dpa in the Experimental Breeder Reactor-II. The material selection, specimens design, experimental apparatus and processes are described. The results of the current test are presented.

  3. 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.

  4. Nonlinear ultrasonic assessment of stress corrosion cracking damage in sensitized 304 stainless steel

    Science.gov (United States)

    Morlock, Florian; Jacobs, Laurence J.; Kim, Jin-Yeon; Singh, Preet; Wall, James J.

    2015-03-01

    This research uses nonlinear Rayleigh surface waves to characterize stress corrosion cracking (SCC) damage in welded 304 Stainless Steel (304 SS). 304 SS is widely used in reactor pressure vessels, where a corrosive environment in combination with applied stress due to high internal pressures can cause SCC. Welds and the nearby heat affected zones (HAZ) in the vessel material are especially sensitive to SCC damage. SCC damage results in microstructural changes such as dislocation formation and microcrack initiation that in the long term lead to reduced structural integrity and material failure. Therefore, the early detection of SCC is crucial to ensure safe operation. It has been shown that the microstructural changes caused by SCC can generate higher harmonic waves when excited harmonically. This research considers different levels of SCC damage induced in samples of welded 304 SS by applying stress to a specimen held in a corrosive medium (Sodium Thiosulfate). A nonlinear Rayleigh surface wave is introduced in the material and the fundamental and the second harmonic waves are measured using wedge detection. The nonlinearity parameter that relates the fundamental and the second harmonic amplitudes, is computed to quantify the SCC damage in each sample. These results are used to demonstrate the feasibility of using nonlinear Rayleigh waves to characterize SCC damage.

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

    Science.gov (United States)

    Moss, Tyler; Was, Gary S.

    2017-04-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Keith J., E-mail: leonardk@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Stevens, Jacqueline N. [AREVA Inc., Lynchburg, VA (United States); Busby, Jeremy T. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2015-11-15

    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. Engineered Barrier System - Assessment of the Corrosion Properties of Copper Canisters. Report from a Workshop. Synthesis and extended abstract

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Peter (ed.) [Quintessa Ltd., Henley-on-Thames (GB)] (and others)

    2006-03-15

    A general impression from literature studies, presentations by workshop participants and the informal hearing with SKB is that there is in general a strong basis for the handling of copper corrosion in safety assessment. Work has been ongoing in the area for many decades and there appears to be a consensus on several key aspects of corrosion, such as the existence of a threshold potential for localised corrosion. This is of key importance for the assessment of corrosion under repository conditions. Localised corrosion has to be evaluated for the initial oxygenated phase. There is a need to demonstrate that the corrosion profile in reality will be similar to those of small scale experiments, i.e. roughening without real pitting. There is also a need to develop a better and more transparent basis for assessing how much oxygen can be available during the early oxygenated phase. Regarding stress corrosion cracking, there is a need for a consistent and possibly more detailed explanation either why it can be completely disregarded, or accounted for by probabilistic methods. Copper is normally assumed to be resistant to corrosion in oxygen free environments. However, this is not correct for the extremely long time period of one million years covered by SKB's safety assessment. Copper will react with sulphide by reduction of water. This reaction is the basis for SKB's performance assessment model for copper corrosion. The key aspect of this model is the availability of sulphide. SKB may need to address in more detail the availability of sulphide from the groundwater and the buffer bentonite and its speciation and solubility behaviour. However, the most sensitive assumption in SKB's modelling appears to be the assumption of zero microbial activity in the buffer throughout the assessment time scale of 10{sup 6} years. A detailed justification of this assumption is needed and possibly also 'what-if' calculations to illustrate consequences if this

  8. Role of Slip Behavior in the Irradiation Assisted Stress Corrosion Cracking in Austenitic Steels

    Science.gov (United States)

    McMurtrey, M. D.; Was, G. S.

    Irradiation assisted stress corrosion cracking appears to be linked to the localization of slip into dislocation channels. Three austenitic steels with varying degrees of cracking susceptibility were irradiated with 2 MeV protons at 360°C to 5 dpa and strained in 288°C simulated BWR conditions. Deformation behavior was characterized by Schmid factors, resolved shear stresses, slip continuity across grain boundaries, and the angle between dislocation channels and the cracked boundaries. Cracking susceptibility was found to correlate with the dislocation channel properties, such as the resolved shear stress and slip continuity at grain boundaries. Higher cracking susceptibility was found at grain boundaries perpendicular to the tensile axis and adjacent to low Schmid factor grains, which have high normal stresses acting on the boundary. Localized deformation and high normal stress have significant roles in IASCC, though they do not fully describe cracking susceptibility.

  9. 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.

  10. 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...... measurements of the hydrogen uptake by cathodically protected steel exposed in heavy clay and peat type soils....

  11. 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

  12. Molecular dynamics analysis of oxidation, segregation and stress corrosion failures of refractory alloys

    Science.gov (United States)

    Verners, Osvalds

    The focuses of the thesis are heating induced segregation/mixing of refractory alloys, along with oxidation and stress corrosion properties of selected fcc metals and thin oxide layers formed on the surfaces thereof. The particular studies include segregation and oxidation simulation of Mo3Ni alloy clusters. These reveal favorable stabilizing oxidation resistance properties due to the Ni component, which diffuses during annealing to the surface of the clusters. A comparative study has been done for different sized Al grains in Fe or Ni bulk matrices. Its results indicate that Ni matrix is favorable due to the grain dissolution and energetic stability properties upon heating and cooling of the structures. Oxidation simulation of the same structures in slab structures indicate that unmixed metals oxidize first and the alloy layer, which forms only for the Ni matrix, eventually segregates to single-metal layers, which oxidize subsequently. The stress corrosion properties of Al oxide slab/thin film structures in water, noble gas and vacuum environments have been studied with the aim of subsequent stress corrosion simulation of alloys or metals with protective surface oxide layers. The obtained results indicate brittle type failures, which involve shear deformation and localized amorphization. The plasticity enhancing fluid environment effects are found to be similar for both reactive and nonreactive species, which indicates significant pressure effects and passivated reactivity of surfaces. Parallel to the corrosion study, strain rate effects and cyclic loading behavior for slab structures in vacuum have been characterized and compared at different temperatures. These indicate time dependent deformation mechanisms including temperature enhanced local amorphization prior to crack formation. Complementary analyses include extended timescale crack behavior of a slab structure in vacuum using parallel replica dynamics and steady state analysis of a slab structure in water

  13. Kinetic studies of the stress corrosion cracking of D6AC steel

    Science.gov (United States)

    Noronha, P. J.

    1975-01-01

    The effect of load interactions on the crack growth velocity of D6AC steel under stress corrosion cracking conditions was determined. The environment was a 3.5 percent salt solution. The modified-wedge opening load specimens were fatigue precracked and subjected to a deadweight loading in creep machines. The effects of load shedding on incubation times and crack growth rates were measured using high-sensitivity compliance measurement techniques. Load shedding results in an incubation time, the length of which depends on the amount of load shed and the baseline stress intensity. The sequence of unloading the specimen also controls the subsequent incubation period. The incubation period is shorter when load shedding passes through zero load than when it does not if the specimen initially had the same baseline stress intensity. The crack growth rates following the incubation period are also different from the steady-state crack growth rate at the operating stress intensity. These data show that the susceptibility of this alloy system to stress corrosion cracking depends on the plane-strain fracture toughness and on the yield strength of the material.

  14. 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)

  15. 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)

  16. Some important considerations in the development of stress corrosion cracking test methods.

    Science.gov (United States)

    Wei, R. P.; Novak, S. R.; Williams, D. P.

    1972-01-01

    Discussion of some of the precaution needs the development of fracture-mechanics based test methods for studying stress corrosion cracking involves. Following a review of pertinent analytical fracture mechanics considerations and of basic test methods, the implications for test corrosion cracking studies of the time-to-failure determining kinetics of crack growth and life are examined. It is shown that the basic assumption of the linear-elastic fracture mechanics analyses must be clearly recognized and satisfied in experimentation and that the effects of incubation and nonsteady-state crack growth must also be properly taken into account in determining the crack growth kinetics, if valid data are to be obtained from fracture-mechanics based test methods.

  17. Investigation of Stress Corrosion Cracking in Magnesium Alloys by Quantitative Fractography Methods

    Directory of Open Access Journals (Sweden)

    Sozańska M.

    2017-06-01

    Full Text Available The article shows that the use of quantitative fracture description may lead to significant progress in research on the phenomenon of stress corrosion cracking of the WE43 magnesium alloy. Tests were carried out on samples in air, and after hydrogenation in 0.1 M Na2SO4 with cathodic polarization. Fracture surfaces were analyzed after different variants of the Slow Strain Rate Test. It was demonstrated that the parameters for quantitative evaluation of fracture surface microcracks can be closely linked with the susceptibility of the WE43 magnesium alloy operating under complex state of the mechanical load in corrosive environments. The final result of the study was the determination of the quantitative relationship between Slow Strain Rate Test parameters, the mechanical properties, and the parameters of the quantitative evaluation of fracture surface (microcracks.

  18. 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)

  19. 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

  20. 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.

  1. Effect of Local Strain Distribution of Cold-Rolled Alloy 690 on Primary Water Stress Corrosion Crack Growth Behavior

    Directory of Open Access Journals (Sweden)

    Kim S.-W.

    2017-06-01

    Full Text Available This work aims to study the stress corrosion crack growth behavior of cold-rolled Alloy 690 in the primary water of a pressurized water reactor. Compared with Alloy 600, which shows typical intergranular cracking along high angle grain boundaries, the cold-rolled Alloy 690, with its heterogeneous microstructure, revealed an abnormal crack growth behavior in mixed mode, that is, in transgranular cracking near a banded region, and in intergranular cracking in a matrix region. From local strain distribution analysis based on local mis-orientation, measured along the crack path using the electron back scattered diffraction method, it was suggested that the abnormal behavior was attributable to a heterogeneity of local strain distribution. In the cold-rolled Alloy 690, the stress corrosion crack grew through a highly strained area formed by a prior cold-rolling process in a direction perpendicular to the maximum principal stress applied during a subsequent stress corrosion cracking test.

  2. 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.

  3. Evaluation of the cracking by stress corrosion in nuclear reactor environments type BWR; Evaluacion del agrietamiento por corrosion bajo esfuerzo en ambientes de reactores nucleares tipo BWR

    Energy Technology Data Exchange (ETDEWEB)

    Arganis J, C. R.

    2010-07-01

    The stress corrosion cracking susceptibility was studied in sensitized, solution annealed 304 steel, and in 304-L welded with a heat treatment that simulated the radiation induced segregation, by the slow strain rate test technique, in a similar environment of a boiling water reactor (BWR), 288 C, 8 MPa, low conductivity and a electrochemical corrosion potential near 200 mV. vs. standard hydrogen electrode (She). The electrochemical noise technique was used for the detection of the initiation and propagation of the cracking. The steels were characterized by metallographic studies with optical and scanning electronic microscopy and by the electrochemical potentiodynamic reactivation of single loop and double loop. In all the cases, the steels present delta ferrite. The slow strain rate tests showed that the 304 steel in the solution annealed condition is susceptible to transgranular stress corrosion cracking (TGSCC), such as in a normalized condition showed granulated. In the sensitized condition the steel showed intergranular stress corrosion cracking, followed by a transition to TGSCC. The electrochemical noise time series showed that is possible associated different time sequences to different modes of cracking and that is possible detect sequentially cracking events, it is means, one after other, supported by the fractographic studies by scanning electron microscopy. The parameter that can distinguish between the different modes of cracking is the re passivation rate, obtained by the current decay rate -n- in the current transients. This is due that the re passivation rate is a function of the microstructure and the sensitization. Other statistic parameters like the localized index, Kurtosis, Skew, produce results that are related with mixed corrosion. (Author)

  4. Effect of stress corrosion cracking at various strain rates on the electrochemical corrosion behavior of Mg-Zn-In-Sn alloy.

    Science.gov (United States)

    Yu, Zhan; Ju, Dongying; Zhao, Hongyang

    2013-12-01

    This study is aimed to determine the effect of stress corrosion with low strain rates on the electrochemical properties of alloy electrode. Stress corrosion cracking tests of Mg-Zn-In-Sn alloy in 3.5 wt.% sodium chloride solutions at 25°C were performed. The effects of the electrochemical properties under the stress corrosion with low strain rates were investigated. The microstructures of cross section were observed by optical microscope. The results showed that the ultimate tensile strengths of Mg-Zn-In-Sn alloy increased and the strain decreased as the strain rates increased. Open circuit potentials (OCP) of Mg-Zn-In-Sn alloy electrode possess stability and the loop currents (LC) were improved with the increasing of stress in the elastic zone. The variation of OCP and LC did not change with the increasing of strain-rate. The microstructure of cross section observing revealed the mechanism of OCP and LC changing. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  5. Development of fiber-delivered laser peening system to prevent stress corrosion cracking of reactor components

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Y.; Kimura, M.; Yoda, M.; Mukai, N.; Sato, K.; Uehara, T.; Ito, T.; Shimamura, M.; Sudo, A.; Suezono, N. [Toshiba Corp., Yokohama (Japan)

    2001-07-01

    The authors have developed a system to deliver water-penetrable intense laser pulses of frequency-doubled Nd:YAG laser through optical fiber. The system is capable of improving a residual stress on water immersed metal material remotely, which is effective to prevent the initiation of stress corrosion cracking (SCC) of reactor components. Experimental results showed that a compressive residual stress with enough amplitude and depth was built in the surface layer of type 304 stainless steel (SUS304) by irradiating laser pulses through optical fiber with diameter of 1 mm. A prototype peening head with miniaturized dimensions of 88 mm x 46 mm x 25 mm was assembled to con-firm the accessibility to the heat affected zone (HAZ) along weld lines of a reactor core shroud. The accessibility was significantly improved owing to the flexible optical fiber and the miniaturized peening head. The fiber delivered system opens up the possibility of new applications of laser peening. (author)

  6. Comparative molecular dynamics study of fcc-Ni nanoplate stress corrosion in water

    Science.gov (United States)

    Verners, Osvalds; van Duin, Adri C. T.

    2015-03-01

    Reactive molecular dynamics studies of stress corrosion properties of Ni metal nanoplate structures in pressurized water at different temperatures, chemical environments and mechanical boundary conditions have been performed. The results indicate reduction of dislocation nucleation barriers due to the water reactions on material surfaces, simulated loading rate and elevated temperature, resulting in reduction of material strength and ductility. It is also found that pre-oxidized surfaces yield increased initial dislocation nucleation barriers. Likewise, significant effects of stress triaxiality on strength, ductility and surface reactivity are also observed by comparison of boundary conditions. Size dependent structure failure modes and distributions of stress and strain have been explored. A possible Ni dissolution mechanism is identified and validated using DFT calculations and metadynamics simulations.

  7. EPRI-NASA Cooperative Project on Stress Corrosion Cracking of Zircaloys. [nuclear fuel failures

    Science.gov (United States)

    Cubicciotti, D.; Jones, R. L.

    1978-01-01

    Examinations of the inside surface of irradiated fuel cladding from two reactors show the Zircaloy cladding is exposed to a number of aggressive substances, among them iodine, cadmium, and iron-contaminated cesium. Iodine-induced stress corrosion cracking (SCC) of well characterized samples of Zircaloy sheet and tubing was studied. Results indicate that a threshold stress must be exceeded for iodine SCC to occur. The existence of a threshold stress indicates that crack formation probably is the key step in iodine SCC. Investigation of the crack formation process showed that the cracks responsible for SCC failure nucleated at locations in the metal surface that contained higher than average concentrations of alloying elements and impurities. A four-stage model of iodine SCC is proposed based on the experimental results and the relevance of the observations to pellet cladding interaction failures is discussed.

  8. Standard Practice for Making and Using C-Ring Stress-Corrosion Test Specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice covers the essential features of the design and machining, and procedures for stressing, exposing, and inspecting C-ring type of stress-corrosion test specimens. An analysis is given of the state and distribution of stress in the C-ring. 1.2 Specific considerations relating to the sampling process and to the selection of appropriate test environments are outside the scope of this practice. 1.3 The values stated in SI units are to be regarded as the standard; The values given in parentheses are for information only. 1.4 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.

  9. Relative susceptibility of titanium alloys to hot-salt stress-corrosion

    Science.gov (United States)

    Gray, H. R.

    1971-01-01

    Susceptibility of titanium alloys to hot-salt stress-corrosion cracking increased as follows: Ti-2Al-11Sn-5Zr-0.2Si(679), Ti-6Al-2Sn-4Zr-2Mo(6242), Ti-6Al-4V(64), Ti-6Al-4V-3Co(643), Ti-8Al-1Mo-1V(811), and Ti-13V-11Cr-3A1(13-11-3). The Ti-5Al-6Sn-2Zr-1Mo-0.25Si(5621S) alloy was both the least and most susceptible depending on heat treatment. Such rankings can be drastically altered by heat-to-heat and processing variations. Residual compressive stresses and cyclic exposures also reduce susceptibility to stress-corrosion. Simulated turbine-engine compressor environmental variables such as air velocity, pressure, dewpoint, salt concentration, and salt deposition temperature have only minor effects. Detection of substantial concentrations of hydrogen in all corroded alloys confirmed the existence of a hydrogen embrittlement mechanism.

  10. Stress corrosion cracking of Ti-8Al-1 Mo-1V in molten salts

    Science.gov (United States)

    Smyrl, W. H.; Blackburn, M. J.

    1975-01-01

    The stress corrosion cracking (SCC) behavior of Ti-8Al-1 Mo-1V has been studied in several molten salt environments. Extensive data are reported for the alloy in highly pure LiCl-KCl. The influence of the metallurgical heat treatment and texture, and the mechanical microstructure show similarities with aqueous solutions at lower temperature. The fracture path and cracking modes are also similar to that found in other environments. The influence of H2O and H(-) in molten LiCl-KCl lead to the conclusion that hydrogen does not play a major role in crack extension in this environment.

  11. The stress corrosion cracking behavior of Alloys 690 and 152 weld in a PWR environment

    Energy Technology Data Exchange (ETDEWEB)

    Alexandreanu, B.; Chopra, O.; Shack, W. [Argonne National Lab., Argonne, Illinois (United States)

    2007-07-01

    'Full text:' Alloys 690 and 152 are the replacement materials of choice for Alloys 600 and, respectively, 182. The objective of this work was to determine the stress corrosion cracking (SCC) crack growth rates (CGRs) in a simulated PWR water environment for the two replacement alloys. The study involved cold-rolled Alloy 690 and a laboratory-prepared Alloy 152 double-V weld. In testing in primary water, both alloys sustained SCC cracking under constant loading conditions in the 10E-11 m/s range. (author)

  12. Initial report on stress-corrosion-cracking experiments using Zircaloy-4 spent fuel cladding C-rings

    Energy Technology Data Exchange (ETDEWEB)

    Smith, H.D.

    1988-09-01

    The Nevada Nuclear Waste Storage Investigations (NNWSI) Project is sponsoring C-ring stress corrosion cracking scoping experiments as a first step in evaluating the potential for stress corrosion cracking of spent fuel cladding in a potential tuff repository environment. The objective is to scope the approximate behavior so that more precise pressurized tube testing can be performed over an appropriate range of stress, without expanding the long-term effort needlessly. The experiment consists of stressing, by compression with a dead weight load, C-rings fabricated from spent fuel cladding exposed to an environment of Well J-13 water held at 90{degree}C. The results indicate that stress corrosion cracking occurs at the high stress levels employed in the experiments. The cladding C-rings, tested at 90% of the stress at which elastic behavior is obtained in these specimens, broke in 25 to 64 d when tested in water. This was about one third of the time required for control tests to break in air. This is apparently the first observation of stress corrosion under the test conditions of relatively low temperature, benign environment but very high stress. The 150 ksi test stress could be applied as a result of the particular specimen geometry. By comparison, the uniaxial tensile yield stress is about 100 to 120 ksi and the ultimate stress is about 150 ksi. When a general model that fits the high stress results is extrapolated to lower stress levels, it indicates that the C-rings in experiments now running at {approximately}80% of the yield strength should take 200 to 225 d to break. 21 refs., 24 figs., 5 tabs.

  13. 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

  14. 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.

  15. Accelerated Corrosion Testing

    Science.gov (United States)

    1982-12-01

    Treaty Organization, Brussels, 1971), p. 449. 14. D. 0. Sprowls, T. J. Summerson, G. M. Ugianski, S. G. Epstein, and H. L. Craig , Jr., in Stress...National Association of Corrosion Engineers Houston, TX, 1972). 22. H. L. Craig , Jr. (ed.), Stress Corrosion-New Approaches, ASTM-STP- 610 (American...62. M. Hishida and H. Nakada, Corrosion 33 (11) 403 (1977). b3. D. C. Deegan and B. E. Wilde, Corrosion 34 (6), 19 (1978). 64. S. Orman, Corrosion Sci

  16. SR-Site - sulphide content in the groundwater at Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Tullborg, E-L (Terralogica, Graabo (Sweden)); Smellie, J. (Conterra, Uppsala (Sweden)); Nilsson, A-Ch (Geosigma, Uppsala (Sweden)); Gimeno, M.J.; Auque, L.F. (Univ. of Zaragoza (Spain)); Wallin, B. (Geokema, Lidingoe (Sweden)); Bruechert, V. (Stockholm Univ. (Sweden)); Molinero, J. (Amphos21, Barcelona (Spain))

    2010-12-15

    Sulphide concentrations in groundwater play a key role in the long term reliability of the metal canisters containing the radioactive waste within a disposal facility for nuclear waste. This is because sulphide in the groundwaters circulating in the vicinity of the deposition tunnels can react with copper in the canisters causing corrosion and therefore reducing their expected lifetime; in a worst case scenario erosion of the bentonite buffer material will expose the canister more rapidly to the fracture groundwater. Sulphide in the groundwater is predominantly microbially produced and thereby controlled by the content of oxidised sulphur sources, organics (carbon sources), reductants (mainly Fe(II), DOC, H{sub 2} and CH{sub 4}), and also flow. In addition, achieved saturation in respect to amorphous Fe-monosulphide will control the possible maximum values and thus limit the Fe2+ and S2- values in the groundwater. The aim of this report is to assess realistic, representative and reliable sulphide groundwater concentrations at present conditions in Laxemar to be considered for use in (future) safety assessments. To achieve this, an evaluation is performed of all the sulphide related data reported from the Laxemar site investigations /Laaksoharju et al. 2009/ and later monitoring campaigns, all of which are stored in the Sicada database. This evaluation shows that values from the Complete Chemical Characterisation (CCC) (i.e. in situ sampling from one or more borehole sections using mobile equipment) are usually lower than those measured during the monitoring phase (i.e. in situ sampling from one borehole section using permanently installed equipment). An exception is borehole KLX01, where values generally lie within the same range as the monitoring samples. For most of the CCC and monitoring sections the last sample in the time series is suggested as representing the 'best possible' sulphide value. When both initial values from CCC (or samples taken with

  17. 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

  18. 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.

  19. Using transmission Kikuchi diffraction to study intergranular stress corrosion cracking in type 316 stainless steels.

    Science.gov (United States)

    Meisnar, Martina; Vilalta-Clemente, Arantxa; Gholinia, Ali; Moody, Michael; Wilkinson, Angus J; Huin, Nicolas; Lozano-Perez, Sergio

    2015-08-01

    Transmission Kikuchi diffraction (TKD), also known as transmission-electron backscatter diffraction (t-EBSD) is a novel method for orientation mapping of electron transparent transmission electron microscopy specimen in the scanning electron microscope and has been utilized for stress corrosion cracking characterization of type 316 stainless steels. The main advantage of TKD is a significantly higher spatial resolution compared to the conventional EBSD due to the smaller interaction volume of the incident beam with the specimen. Two 316 stainless steel specimen, tested for stress corrosion cracking in hydrogenated and oxygenated pressurized water reactor chemistry, were characterized via TKD. The results include inverse pole figure (IPFZ) maps, image quality maps and misorientation maps, all acquired in very short time (crack with respect to the grain boundary, deformation bands, twinning and slip. Furthermore, TKD has been used to measure the grain boundary misorientation and establish a gauge for quantifying plastic deformation at the crack tip and other regions in the surrounding matrix. Both grain boundary migration and slip transfer have been detected as well. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Mitigation of Intergranular Stress Corrosion Cracking in Al-Mg by Electrochemical Potential Control

    Science.gov (United States)

    McMahon, M. E.; Scully, J. R.; Burns, J. T.

    2017-08-01

    Intergranular stress corrosion cracking in the Al-Mg alloy AA5456-H116 is suppressed via cathodic polarization in 0.6 M NaCl, saturated (5.45 M) NaCl, 2 M MgCl2, and saturated (5 M) MgCl2. Three zones of intergranular stress corrosion cracking (IG-SCC) susceptibility correlate with pitting potentials of unsensitized AA5456-H116 and pure β phase (Al3Mg2) in each solution. These critical potentials reasonably describe the influence of α Al matrix and β phase dissolution rates on IG-SCC severity. Complete inhibition occurred at applied potentials of -1.0 V and -1.1 V versus saturated calomel electrode ( V SCE) in 0.6 M NaCl. Whereas only partial mitigation of IG-SCC was achieved at -0.9 V SCE in 0.6 M NaCl and at -0.9, -1.0, and -1.1 V SCE in the more aggressive environments. Correlation of pitting potentials in bulk environments with IG-SCC behavior suggests an effect of bulk environment [Cl-] and pH on the stabilized crack tip chemistry.

  1. Aqueous chloride stress corrosion cracking of titanium: A comparison with environmental hydrogen embrittlement

    Science.gov (United States)

    Nelson, H. G.

    1973-01-01

    The physical characteristics of stress corrosion cracking of titanium in an aqueous chloride environment are compared with those of embrittlement of titanium by a gaseous hydrogen environment in an effort to help contribute to the understanding of the possible role of hydrogen in the complex stress corrosion cracking process. Based on previous studies, the two forms of embrittlement are shown to be similar at low hydrogen pressures (100 N/sqm) but dissimilar at higher hydrogen pressures. In an effort to quantify this comparison, tests were conducted in an aqueous chloride solution using the same material and test techniques as had previously been employed in a gaseous hydrogen environment. The results of these tests strongly support models based on hydrogen as the embrittling species in an aqueous chloride environment. Further, it is shown that if hydrogen is the causal species, the effective hydrogen fugacity at the surface of titanium exposed to an aqueous chloride environment is equivalent to a molecular hydrogen pressure of approximately 10 N/sqm.

  2. 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.

  3. 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.

  4. 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

  5. Modeling of stresses at grain boundaries with respect to occurrence of stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Kozaczek, K.J. [Oak Ridge National Lab., TN (United States); Sinharoy, A.; Ruud, C.O. [Pennsylvania State Univ., University Park, PA (United States); McIlree, A.R. [Electric Power Research Institute, Palo Alto, CA (United States)

    1995-12-31

    The distributions of elastic stresses/strains in the grain boundary regions were studied by the analytical and the finite element models. The grain boundaries represent the sites where stress concentration occurs as a result of discontinuity of elastic properties across the grain boundary and the presence of second phase particles elastically different from the surrounding matrix grains. A quantitative analysis of those stresses for steels and nickel based alloys showed that the stress concentrations in the grain boundary regions are high enough to cause a local microplastic deformation even when the material is in the macroscopic elastic regime. The stress redistribution as a result of such a plastic deformation was discussed.

  6. Stress corrosion cracking and corrosion fatigue characterisation of MgZn1Ca0.3 (ZX10) in a simulated physiological environment.

    Science.gov (United States)

    Jafari, Sajjad; Raman, R K Singh; Davies, Chris H J; Hofstetter, Joelle; Uggowitzer, Peter J; Löffler, Jörg F

    2017-01-01

    Magnesium (Mg) alloys have attracted great attention as potential materials for biodegradable implants. It is essential that an implant material possesses adequate resistance to cracking/fracture under the simultaneous actions of corrosion and mechanical stresses, i.e., stress corrosion cracking (SCC) and/or corrosion fatigue (CF). This study investigates the deformation behaviour of a newly developed high-strength low-alloy Mg alloy, MgZn1Ca0.3 (ZX10), processed at two different extrusion temperatures of 325 and 400°C (named E325 and E400, respectively), under slow strain tensile and cyclic tension-compression loadings in air and modified simulated body fluid (m-SBF). Extrusion resulted in a bimodal grain size distribution with recrystallised grain sizes of 1.2 μm ± 0.8 μm and 7 ± 5 μm for E325 and E400, respectively. E325 possessed superior tensile and fatigue properties to E400 when tested in air. This is mainly attributed to a grain-boundary strengthening mechanism. However, both E325 and E400 were found to be susceptible to SCC at a strain rate of 3.1×10-7s-1 in m-SBF. Moreover, both E325 and E400 showed similar fatigue strength when tested in m-SBF. This is explained on the basis of crack initiation from localised corrosion following tests in m-SBF. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  7. FITNESS-FOR-SERVICE ASSESSMENT FOR A RADIOACTIVE WASTE TANK THAT CONTAINS STRESS CORROSION CRACKS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B; James Elder, J; Rodney Vandekamp, R; Charles Mckeel, C

    2009-04-23

    Radioactive wastes are confined in 49 underground storage tanks at the Savannah River Site. The tanks are examined by ultrasonic (UT) methods for thinning, pitting, and stress corrosion cracking in order to assess fitness-for-service. During an inspection in 2002, ten cracks were identified on one of the tanks. Given the location of the cracks (i.e., adjacent to welds, weld attachments, and weld repairs), fabrication details (e.g., this tank was not stress-relieved), and the service history the degradation mechanism was stress corrosion cracking. Crack instability calculations utilizing API-579 guidance were performed to show that the combination of expected future service condition hydrostatic and weld residual stresses do not drive any of the identified cracks to instability. The cracks were re-inspected in 2007 to determine if crack growth had occurred. During this re-examination, one indication that was initially reported as a 'possible perpendicular crack <25% through wall' in 2002, was clearly shown not to be a crack. Additionally, examination of a new area immediately adjacent to other cracks along a vertical weld revealed three new cracks. It is not known when these new cracks formed as they could very well have been present in 2002 as well. Therefore, a total of twelve cracks were evaluated during the re-examination. Comparison of the crack lengths measured in 2002 and 2007 revealed that crack growth had occurred in four of the nine previously measured cracks. The crack length extension ranged from 0.25 to 1.8 inches. However, in all cases the cracks still remained within the residual stress zone (i.e., within two to three inches of the weld). The impact of the cracks that grew on the future service of Tank 15 was re-assessed. API-579 crack instability calculations were again performed, based on expected future service conditions and trended crack growth rates for the future tank service cycle. The analysis showed that the combined hydrostatic

  8. Growth and stability of stress corrosion cracks in large-diameter BWR piping. Volume 1: summary. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hale, D A; Heald, J D; Horn, R M; Jewett, C W; Kass, J N; Mehta, H S; Ranganath, S; Sharma, S R

    1982-07-01

    This report presents the results of a research program conducted to evaluate the behavior of hypothetical stress corrosion cracks in large diameter austenitic piping. The program included major tasks, a design margin assessment, an evaluation of crack growth and crack arrest, and development of a predictive model. As part of the margin assessment, the program developed diagrams which predicted net section collapse as a function of crack size. In addition, plasticity and dynamic load effects were also considered in evaluating collapse. Analytical methods for evaluating these effects were developed and were benchmarked by dynamic tests of 4-in.-diameter piping. The task of evaluating the growth behavior of stress corrosion cracks focused on developing constant load and cyclic growth rate data that could be used with the predictive model. Secondly, laboratory tests were performed to evaluate the conditions under which growing stress corrosion cracks would arrest when they intersected stress corrosion resistant weld metal. The third task successfully developed a model to predict the behavior of cracks in austenitic piping. This model relies on crack growth data and the critical crack size predicted by the net section collapse approach.

  9. 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

    Intercrystalline stress corrosion cracking has occurred in the Aagesta reactor in three so-called inspection tubes made of Inconel 600. The tubes had been exposed to 217 deg C light water, containing 1-4 ppm LiOH (later KOH) but only small amounts of oxygen, chloride and other impurities. Some of the circumferential cracks developed in or at crevices on the outside surface. At these positions constituents dissolved in the water may have concentrated. The crevices are likely to have contained a gas phase, mainly nitrogen. Local boiling in the crevices may also have occurred. Some few cracks were also found outside the crevice region. Irradiation effects can be neglected. No surface contamination could be detected except for a very minor fluoride content (1 {mu}g/cm{sup 2}). The failed tubes had been subjected to high stresses, partly remaining from milling, partly induced by welding operations. The possibility that stresses slightly above the 0.2 per cent offset yield strength have occurred at the operating temperature cannot be excluded. The cracked tube material contained a large amount of carbide particles and other precipitates, both at grain boundaries and in the interior of grains. The particles appeared as stringers in circumferential zones. Zones depleted in precipitates were found along grain boundaries. The failed tube turned out to have an unusually high mechanical strength, likely due to a combination of some kind of ageing process and cold work (1.0 - 1.3 per cent plastic strain). Laboratory exposures of stressed surplus material in high purity water and in 1 M LiOH at 220 deg C showed some pitting but no cracking after 6800 h and 5900 h respectively. Though the encountered failures may have developed because of influence of some few or several of the above-mentioned detrimental factors, the actual cause cannot be stated with certainty. In the literature information is given concerning intercrystalline stress corrosion cracking of Inconel 600 both in

  10. Effects of temperature and pressure on stress corrosion cracking behavior of 310S stainless steel in chloride solution

    Science.gov (United States)

    Zhong, Yunpan; Zhou, Cheng; Chen, Songying; Wang, Ruiyan

    2017-01-01

    310S is an austenitic stainless steel for high temperature applications, having strong resistance of oxidation, hydrogen embrittlement and corrosion. Stress corrosion cracking(SCC) is the main corrosion failure mode for 310S stainless steel. Past researched about SCC of 310S primarily focus on the corrosion mechanism and influence of temperature and corrosive media, but few studies concern the combined influence of temperature, pressure and chloride. For a better understanding of temperature and pressure's effects on SCC of 310S stainless steel, prepared samples are investigated via slow strain rate tensile test(SSRT) in different temperature and pressure in NACE A solution. The result shows that the SCC sensibility indexes of 310S stainless steel increase with the rise of temperature and reach maximum at 10MPa and 160°C, increasing by 22.3% compared with that at 10 MPa and 80 °C. Instead, the sensibility decreases with the pressure up. Besides, the fractures begin to transform from the ductile fracture to the brittle fracture with the increase of temperature. 310S stainless steel has an obvious tendency of stress corrosion at 10MPa and 160°C and the fracture surface exists cleavage steps, river patterns and some local secondary cracks, having obvious brittle fracture characteristics. The SCC cracks initiate from inclusions and tiny pits in the matrix and propagate into the matrix along the cross section gradually until rupture. In particular, the oxygen and chloride play an important role on the SCC of 310S stainless steel in NACE A solution. The chloride damages passivating film, causing pitting corrosion, concentrating in the cracks and accelerated SSC ultimately. The research reveals the combined influence of temperature, pressure and chloride on the SCC of 310S, which can be a guide to the application of 310S stainless steel in super-heater tube.

  11. 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. Copyright © 2011 Wiley Periodicals, Inc.

  12. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Experimental study on stress corrosion crack propagation rate of FV520B in carbon dioxide and hydrogen sulfide solution

    Science.gov (United States)

    Qin, Ming; Li, Jianfeng; Chen, Songying; Qu, Yanpeng

    FV520B steel is a kind of precipitation hardening Martensitic stainless steel, it has high-strength, good plasticity and good corrosion resistance. Stress corrosion cracking (SCC) is one of the main corrosion failure mode for FV520B in industrial transportation of natural gas operation. For a better understanding the effect on SCC of FV520B, the improved wedge opening loading (WOL) specimens and constant displacement loading methods were employed in experimental research in carbon dioxide and hydrogen sulfide solution. The test results showed that the crack propagation rate is 1.941 × 10-7-5.748 × 10-7 mm/s, the stress intensity factor KISCC is not more than 36.83 MPa √{ m } . The rate increases with the increasing of the crack opening displacement. Under the condition of different initial loading, KISCC generally shows a decreasing tendency with the increase in H2S concentration, and the crack propagation rate showed an increasing trend substantially. For the enrichment of sulfur ion in the crack tip induced the generation of pitting corrosion, promoting the surrounding metal formed the corrosion micro batteries, the pit defects gradually extended and connected with the adjacent pit to form a small crack, leading to further propagation till cracking happened. Fracture microscopic morphology displayed typical brittle fracture phenomena, accompanying with trans-granular cracking, river shape and sector, many second cracks on the fracture surface.

  14. Hydrogen Cracking and Stress Corrosion of Pressure Vessel Steel ASTM A543

    Science.gov (United States)

    AlShawaf, Ali Hamad

    with the previously used plain carbon steel and other currently used pressure vessel steels was successfully completed. The experimental and computational results of the Q&T HSLA steel agreed well with each other. The susceptibility of the Q&T A543 steel to stress corrosion cracking was investigated using the slow strain rate testing under different environments and conditions. Also, advanced corrosion study using the electrochemical impedance spectroscopy was done at different conditions. The corrosion study revealed that this A543 steel is prone to form pits in most of the conditions. The model results in the corrosion study were validated with the Gamry Echem Analyst software that A543 steel tends to form pits in the tested environment.

  15. 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 .

  16. 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.

  17. Stress corrosion crack initiation of alloy 600 in PWR primary water

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-01

    Stress corrosion crack (SCC) initiation of three mill-annealed (MA) alloy 600 heats in simulated pressurized water reactor primary water has been investigated using constant load tests equipped with in-situ direct current potential drop (DCPD) measurement capabilities. SCC initiation times were greatly reduced by a small amount of cold work. Shallow intergranular (IG) attack and/or cracks were found on most high-energy grain boundaries intersecting the surface with only a small fraction evolving into larger cracks and IGSCC growth. Crack depth profiles were measured and related to DCPD-detected initiation response. Processes controlling the SCC initiation in MA alloy 600 are discussed. IN PRESS, CORRECTED PROOF, 05/02/2017 - mfl

  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 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.

  20. Dissociative chemisorption of O2 inducing stress corrosion cracking in silicon crystals.

    Science.gov (United States)

    Gleizer, Anna; Peralta, Giovanni; Kermode, James R; De Vita, Alessandro; Sherman, Dov

    2014-03-21

    Fracture experiments to evaluate the cleavage energy of the (110)[1 1 0] and (111)[1 1 2] cleavage systems in silicon at room temperature and humidity give 2.7 ± 0.3 and 2.2 ± 0.2 J/m(2), respectively, lower than any previous measurement and inconsistent with density functional theory (DFT) surface energy calculations of 3.46 and 2.88 J/m(2). However, in an inert gas environment, we measure values of 3.5 ± 0.2 and 2.9 ± 0.2 J/m(2), consistent with DFT, that suggest a previously undetected stress corrosion cracking scenario for Si crack initiation in room conditions. This is fully confirmed by hybrid quantum-mechanics-molecular-mechanics calculations.

  1. Stress Corrosion Cracking and Fatigue Crack Growth Studies Pertinent to Spacecraft and Booster Pressure Vessels

    Science.gov (United States)

    Hall, L. R.; Finger, R. W.

    1972-01-01

    This experimental program was divided into two parts. The first part evaluated stress corrosion cracking in 2219-T87 aluminum and 5Al-2.5Sn (ELI) titanium alloy plate and weld metal. Both uniform height double cantilever beam and surface flawed specimens were tested in environments normally encountered during the fabrication and operation of pressure vessels in spacecraft and booster systems. The second part studied compatibility of material-environment combinations suitable for high energy upper stage propulsion systems. Surface flawed specimens having thicknesses representative of minimum gage fuel and oxidizer tanks were tested. Titanium alloys 5Al-2.5Sn (ELI), 6Al-4V annealed, and 6Al-4V STA were tested in both liquid and gaseous methane. Aluminum alloy 2219 in the T87 and T6E46 condition was tested in fluorine, a fluorine-oxygen mixture, and methane. Results were evaluated using modified linear elastic fracture mechanics parameters.

  2. 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.

  3. 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)

  4. Stress corrosion cracking behavior of annealed and cold worked 316L stainless steel in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Sáez-Maderuelo, A., E-mail: alberto.saez@ciemat.es; Gómez-Briceño, D.

    2016-10-15

    Highlights: • The alloy 316L is susceptible to stress corrosion cracking in supercritical water. • The susceptibility of alloy 316L increases with temperature and plastic deformation. • Dynamic strain ageing processes may be active in the material. - Abstract: The supercritical water reactor (SCWR) is one of the more promising designs considered by the Generation IV International Forum due to its high thermal efficiency and improving security. To build this reactor, standardized structural materials used in light water reactors (LWR), like austenitic stainless steels, have been proposed. These kind of materials have shown an optimum behavior to stress corrosion cracking (SCC) under LWR conditions except when they are cold worked. It is known that physicochemical properties of water change sharply with pressure and temperature inside of the supercritical region. Owing to this situation, there are several doubts about the behavior of candidate materials like austenitic stainless steel 316L to SCC in the SCWR conditions. In this work, alloy 316L was studied in deaerated SCW at two different temperatures (400 °C and 500 °C) and at 25 MPa in order to determine how changes in this variable influence the resistance of this material to SCC. The influence of plastic deformation in the behavior of alloy 316L to SCC in SCW was also studied at both temperatures. Results obtained from these tests have shown that alloy 316L is susceptible to SCC in supercritical water reactor conditions where the susceptibility of this alloy increases with temperature. Moreover, prior plastic deformation of 316L SS increased its susceptibility to environmental cracking in SCW.

  5. 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.)

  6. Dissolution Condensation Mechanism of Stress Corrosion Cracking in Liquid Metals: Driving Force and Crack Kinetics

    Science.gov (United States)

    Glickman, Evgeny E.

    2011-02-01

    Stress corrosion cracking (SCC) in aqueous solution is driven by exothermic reactions of metal oxidation. This stimulus, as well as classical mechanisms of SCC, does not apply to SCC in liquid metals (LMs). In the framework of the dissolution-condensation mechanism (DCM), we analyzed the driving force and crack kinetics for this nonelectrochemical mode of SCC that is loosely called "liquid metal embrittlement" (LME). According to DCM, a stress-induced increase in chemical potential at the crack tip acts as the driving force for out-of-the-tip diffusion mass transfer that is fast because diffusion in LMs is very fast and surface energy at the solid-liquid interface is small. In this article, we review two versions of DCM mechanism, discuss the major physics behind them, and develop DCM further. The refined mechanism is applied then to the experimental data on crack velocity V vs stress intensity factor, the activation energy of LME, and alloying effects. It is concluded that DCM provides a good conceptual framework for analysis of a unified kinetic mechanism of LME and may also contribute to SCC in aqueous solutions.

  7. A mechanical property and stress corrosion evaluation of Custom 455 stainless steel alloy

    Science.gov (United States)

    Montano, J. W.

    1972-01-01

    The mechanical and stress corrosion properties are presented of vacuum melted Custom 455 stainless steel alloy bar (1.0-inch diameter) and sheet (0.083-inch thick) material aged at 950 F, 1000 F, and 1050 F. Low temperature mechanical properties were determined at temperatures of 80 F, 0 F, -100 F, and -200 F. For all three aging treatments, the ultimate tensile and 0.2 percent offset yield strengths increased with decreasing test temperatures while the elongation held fairly constant down to -100 F and decreased at -200 F. Reduction in Area decreased moderately with decreasing temperature for the longitudinal round (0.250-inch diameter) specimens. Notched tensile strength and charpy V-notched impact strength decreased with decreasing test temperature. For all three aging treatments, no failures were observed in the unstressed specimens or the specimens stressed to 50, 75, and 100 percent of their yield strengths for 180 days of alternate immersion testing in a 3.5 percent NaCl solution. As indicated by the results of tensile tests performed after alternate immersion testing, the mechanical properties of Custom 455 alloy were not affected by stress or exposure under the conditions of the evaluation.

  8. Thermodynamic data for copper. Implications for the corrosion of copper under repository conditions

    Energy Technology Data Exchange (ETDEWEB)

    Puigdomenech, I. [Royal Inst. of Tech., Stockholm (Sweden); Taxen, C. [Swedish Corrosion Inst., Stockholm (Sweden)

    2000-08-01

    The stability of copper canisters has a central role in the safety concept for the planned nuclear spent fuel repository in Sweden. The corrosion of copper canisters will be influenced by the chemical and physical environment in the near-field of the repository, and thermodynamic equilibrium calculations provide the basis for understanding this system. Thermodynamic data have been selected in this work for solids and aqueous species in the system: Cu - H{sub 2}O - H{sup +} - H{sub 2} - F{sup -} - Cl{sup -} - S{sup 2-} - SO{sub 4}{sup 2-} - NO{sub 3}{sup -} - NO{sub 2}{sup -} - NH{sub 4}{sup +} PO{sub 4}{sup 3-} - CO{sub 3}{sup 2+} . For some reactions and compounds, for which no experimental information on temperature effects was available, entropy and heat capacity values have been estimated. The compiled data were used to calculate thermodynamic equilibria for copper systems up to 100 deg C. The stability of copper in contact with granitic groundwaters has been illustrated using chemical equilibrium diagrams, with he following main conclusions: Dissolved sulphide and O{sub 2} in groundwater are the most damaging components for copper corrosion. If available, HS{sup -} will react quantitatively with copper to form a variety of sulphides. However, sulphide concentrations in natural waters are usually low, because it forms sparingly soluble solids with transition metals, including Fe(II), which is wide-spread in reducing environments. Chloride can affect negatively copper corrosion. High concentrations (e.g., [Cl{sup -}]TOT > 60 g/l) may be unfavourable for the general corrosion of copper in combination with in the following circumstances: Low pH (< 4 at 25 deg C, or < 5 at 100 deg C). The presence of other oxidants than H{sup +}. The negative effects of Cl{sup -} are emphasised at higher temperatures. The chloride-enhancement of general corrosion may be beneficial for localised corrosion: pitting and stress corrosion cracking. The concept of redox potential, E

  9. Microbial Corrosion and Cracking in Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    1998-01-01

    and for recommendations in regards to electrochemical monitoring of MIC. The work presented here and further studies are also planned to lead to a Ph.D. thesis on "MIC monitoring based on mechanisms of corrosion".The results of laboratory experiments conducted in the period 1995 to 1997 are summarised. Conclusions...... will be based on results from the entire 3 year period, but only selected experimental data primarily from the latest experiments will be presented in detail here.Microbial corrosion of carbon steel under influence of sulphate-reducing bacteria (SRB) is characterised by the formation of both biofilm...... and corrosion products (ferrous sulphides) on the metal surface. Experiments have been conducted on carbon steel exposed in near neutral (pH 6 to 8.5) saline hydrogen sulphide environment (0 to 100 mg/l total dissolved sulphide) for a period of 14 days. Furthermore coupons have been exposed in a bioreactor...

  10. On-line corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Richter, Sonja; Thorarinsdottir, R.I.; Hilbert, Lisbeth Rischel

    2004-01-01

    corrosion monitoring a challenge. Under normal conditions the pH is high (app. 9), conductivity is low (app. 10-200 µS/cm) and the concentration of dissolved oxygen is negligible. The low corrosion rates (in the order of µm/y) are difficult to measure and furthermore, factors such as hydrogen sulphide....... In order to assess both general corrosion and localized corrosion, it is necessary to apply more than one monitoring technique simultaneously, ZRA or EN for measuring localized corrosion and LPR or ER for measuring general corrosion rate. The advantage of monitoring localized corrosion is indisputable...

  11. 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.

  12. On the Limiting Electrode Potential in Cavities and Its Role in Deciding between SCC (Stress Corrosion Cracking) and HC (Hydrogen Cracking) in Metals.

    Science.gov (United States)

    1984-02-01

    Z. Metallkunde , 46, 681 (1955). 12. R. Bakish and W. Robertson, Trans. AIME, 206, 1277 (1956). 13. H. W. Pickering, Corrosion, 25, 289 (1969). 14. L...Graf and J. Budke, Z. Metallkunde , 46, 378 (1955). 15. L. Graf, Fundamental Aspects of Stress Corrosion Cracking, R. W. Staehle, A. J. Forty and D

  13. Development of stress corrosion cracking resistant welds of 321 stainless steel by simple surface engineering

    Science.gov (United States)

    Mankari, Kamal; Acharyya, Swati Ghosh

    2017-12-01

    We hereby report a simple surface engineering technique to make AISI grade 321 stainless steel (SS) welds resistant to stress corrosion cracking (SCC) in chloride environment. Heat exchanger tubes of AISI 321 SS, welded either by (a) laser beam welding (LBW) or by (b) metal inert gas welding (MIG) were used for the study. The welds had high magnitude of tensile residual stresses and had undergone SCC in chloride environment while in service. The welds were characterized using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Subsequently, the welded surfaces were subjected to buffing operation followed by determination of residual stress distribution and surface roughness by XRD and surface profilometer measurements respectively. The susceptibility of the welds to SCC was tested in buffed and un-buffed condition as per ASTM G-36 in boiling MgCl2 for 5 h and 10 h, followed by microstructural characterization by using optical microscope and FESEM. The results showed that the buffed surfaces (both welds and base material) were resistant to SCC even after 10 h of exposure to boiling MgCl2 whereas the un-buffed surfaces underwent severe SCC for the same exposure time. Buffing imparted high magnitude of compressive stresses on the surface of stainless steel together with reduction in its surface roughness and reduction in plastic strain on the surface which made the welded surface, resistant to chloride assisted SCC. Buffing being a very simple, portable and economic technique can be easily adapted by the designers as the last step of component fabrication to make 321 stainless steel welds resistant to chloride assisted SCC.

  14. Simulated Service and Stress Corrosion Cracking Testing for Friction Stir Welded Spun Form Domes

    Science.gov (United States)

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

    2010-01-01

    Damage tolerance testing development was required to help qualify a new spin forming dome fabrication process for the Ares 1 program at Marshall Space Flight Center (MSFC). One challenge of the testing was due to the compound curvature of the dome. The testing was developed on a sub-scale dome with a diameter of approximately 40 inches. The simulated service testing performed was based on the EQTP1102 Rev L 2195 Aluminum Lot Acceptance Simulated Service Test and Analysis Procedure generated by Lockheed Martin for the Space Shuttle External Fuel Tank. This testing is performed on a specimen with an induced flaw of elliptical shape generated by Electrical Discharge Machining (EDM) and subsequent fatigue cycling for crack propagation to a predetermined length and depth. The specimen is then loaded in tension at a constant rate of displacement at room temperature until fracture occurs while recording load and strain. An identical specimen with a similar flaw is then proof tested at room temperature to imminent failure based on the critical offset strain achieved by the previous fracture test. If the specimen survives the proof, it is then subjected to cryogenic cycling with loads that are a percentage of the proof load performed at room temperature. If all cryogenic cycles are successful, the specimen is loaded in tension to failure at the end of the test. This standard was generated for flat plate, so a method of translating this to a specimen of compound curvature was required. This was accomplished by fabricating a fixture that maintained the curvature of the specimen rigidly with the exception of approximately one-half inch in the center of the specimen containing the induced flaw. This in conjunction with placing the center of the specimen in the center of the load train allowed for successful testing with a minimal amount of bending introduced into the system. Stress corrosion cracking (SCC) tests were performed using the typical double beam assembly and with 4

  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. The stress corrosion cracking behavior of alloys 690 and 152 WELD in a PWR environment.

    Energy Technology Data Exchange (ETDEWEB)

    Alexandreanu, B.; Chopra, O. K.; Shack, W. J. (Nuclear Engineering Division); ( EVS); ( ESE)

    2009-01-01

    Alloys 690 and 152 are the replacement materials of choice for Alloys 600 and 182, respectively. The latter two alloys are used as structural materials in pressurized water reactors (PWRs) and have been found to undergo stress corrosion cracking (SCC). The objective of this work is to determine the crack growth rates (CGRs) in a simulated PWR water environment for the replacement alloys. The study involved Alloy 690 cold-rolled by 26% and a laboratory-prepared Alloy 152 double-J weld in the as-welded condition. The experimental approach involved pre-cracking in a primary water environment and monitoring the cyclic CGRs to determine the optimum conditions for transitioning from the fatigue transgranular to intergranular SCC fracture mode. The cyclic CGRs of cold-rolled Alloy 690 showed significant environmental enhancement, while those for Alloy 152 were minimal. Both materials exhibited SCC of 10{sup -11} m/s under constant loading at moderate stress intensity factors. The paper also presents tensile property data for Alloy 690TT and Alloy 152 weld in the temperature range 25--870 C.

  17. Irradiation-Assisted Stress-Corrosion Cracking of Nitinol During eBeam Sterilization

    Science.gov (United States)

    Smith, Stuart A.; Gause, Brock; Plumley, David; Drexel, Masao J.

    2012-12-01

    Medical device fractures during gamma and electron beam (eBeam) sterilization have been reported. Two common factors in these device fractures were a constraining force and the presence of fluorinated ethylene propylene (FEP). This study investigated the effects of eBeam sterilization on constrained light-oxide nitinol wires in FEP. The goal was to recreate these fractures and determine their root cause. Superelastic nitinol wires were placed inside FEP tubes and constrained with nominal outer fiber strains of 10, 15, and 20%. These samples were then subjected to a range of eBeam sterilization doses up to 400 kGy and compared with unconstrained wires also subjected to sterilization. Fractures were observed at doses of >100 kGy. Analysis of the fracture surfaces indicated that the samples failed due to irradiation-assisted stress-corrosion cracking (IASCC). This same effect was also observed to occur with PTFE at 400 kGy. These results suggest that nitinol is susceptible to IASCC when in the presence of a constraining stress, fluorinated polymers, and irradiation.

  18. Standard test method for determining susceptibility to stress-corrosion cracking of 2XXX and 7XXX Aluminum alloy products

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1998-01-01

    1.1 This test method covers a uniform procedure for characterizing the resistance to stress-corrosion cracking (SCC) of high-strength aluminum alloy wrought products for the guidance of those who perform stress-corrosion tests, for those who prepare stress-corrosion specifications, and for materials engineers. 1.2 This test method covers method of sampling, type of specimen, specimen preparation, test environment, and method of exposure for determining the susceptibility to SCC of 2XXX (with 1.8 to 7.0 % copper) and 7XXX (with 0.4 to 2.8 % copper) aluminum alloy products, particularly when stressed in the short-transverse direction relative to the grain structure. 1.3 The values stated in SI units are to be regarded as standard. The inch-pound units in parentheses are provided for information. 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 de...

  19. The stress corrosion resistance and the cryogenic temperature mechanical properties of hot rolled Nitronic 32 bar material

    Science.gov (United States)

    Montano, J. W. L.

    1977-01-01

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of hot rolled and centerless ground Nitronic 32 stainless steel bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing smooth tensile strength with decreasing temperature to liquid hydrogen temperature. However, below -200 F (-129.0 C) the notched tensile strength decreased slightly and below -320 F (-196.0 C) the decrease was significant. The elongation and reduction of area decreased drastically at temperatures below -200 F (-129.0 C). The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens stressed to 0, 75, and 90 percent of the 0.2 percent yield strength and on transverse 'C'-ring specimens stressed to 75 and 90 percent of the yield strength and exposed to: alternate immersion in a 3.5 percent NaCl bath, humidity cabinet environment, and a 5 percent salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack; however, the 'C'-rings exposed to the alternate immersion and to the salt spray experienced some shallow etching and pitting, respectively. Small cracks appeared in two of the 'C'-rings after one month exposure to the salt spray.

  20. Properties, weldability and corrosion behavior of supermartensitic stainless steels for on- and offshore applications

    Energy Technology Data Exchange (ETDEWEB)

    Taban, Emel; Kaluc, Erdinc; Ojo, Olatunji Oladimeji [Kocaeli Univ. (Turkey). Welding Research, Education and Training Center

    2016-08-01

    Stimulated material-environment interactions inside and around flowlines of deep or ultra deep wells during oil and gas exploration, and fabrication economy of pipelines have been the major challenges facing the oil and gas industries. Presumably, an extensive focus on high integrity, performance and material economy of flowlines have realistically made supermartensitic stainless steels (SMSS) efficient and effective material choices for fabricating onshore and offshore pipelines. Supermartensitic stainless steels exhibit high strength, good low temperature toughness, sufficient corrosion resistance in sweet and mildly sour environments, and good quality weldability with both conventional welding processes and modern welding methods such as laser beam welding, electron beam welding and hybrid welding approaches. In terms of economy, supermartensitic stainless steels are cheaper and they are major replacements for more expensive duplex stainless steels required for tubing applications in the oil and gas industry. However, weld areas of SMSS pipes are exposed to sulphide stress cracking (SSC), so intergranular stress corrosion cracking (IGSCC) or stress corrosion cracking can occur. In order to circumvent this risk of cracking, a post-weld heat treatment (PWHT) for 5 minutes at about 650 C is recommended. This paper provides detailed literature perusal on supermartensitic stainless steels, their weldability and corrosion behaviors. It also highlights a major research area that has not been thoroughly expounded in literature; fatigue loading behaviors of welded SMSS under different corrosive environments have not been thoroughly detailed in literature.

  1. Recent progress to understand stress corrosion cracking in sodium borosilicate glasses: linking the chemical composition to structural, physical and fracture properties

    Science.gov (United States)

    Rountree, Cindy L.

    2017-08-01

    This topical review is dedicated to understanding stress corrosion cracking in oxide glasses and specifically the SiO_2{\\text-B_2O_3{\\text-}Na_2O} (SBN) ternary glass systems. Many review papers already exist on the topic of stress corrosion cracking in complex oxide glasses or overly simplified glasses (pure silica). These papers look at how systematically controlling environmental factors (pH, temperature...) alter stress corrosion cracking, while maintaining the same type of glass sample. Many questions still exist, including: What sets the environmental limit? What sets the velocity versus stress intensity factor in the slow stress corrosion regime (Region I)? Can researchers optimize these two effects to enhance a glass’ resistance to failure? To help answer these questions, this review takes a different approach. It looks at how systemically controlling the glass’ chemical composition alters the structure and physical properties. These changes are then compared and contrasted to the fracture toughness and the stress corrosion cracking properties. By taking this holistic approach, researchers can begin to understand the controlling factors in stress corrosion cracking and how to optimize glasses via the initial chemical composition.

  2. High Temperature Corrosion under Laboratory Conditions Simulating Biomass-Firing: A Comprehensive Characterization of Corrosion Products

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2014-01-01

    characterization of the corrosion products. The corrosion products consisted of three layers: i) the outermost layer consisting of a mixed layer of K2SO4 and FexOy on a partly molten layer of the initial deposit, ii) the middle layer consists of spinel (FeCr2O4) and Fe2O3, and iii) the innermost layer is a sponge......-like Ni3S2 containing layer. At the corrosion front, Cl-rich protrusions were observed. Results indicate that selective corrosion of Fe and Cr by Cl, active oxidation and sulphidation attack of Ni are possible corrosion mechanisms....

  3. The properties of protective oxide scales containing cerium on alloy 800H in oxidizing and oxidizing/sulphidizing environments

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; Fransen, T.; Geerdink, Bert; Gellings, P.J.; Stroosnijder, M.F.

    1991-01-01

    The corrosion protection of oxide scales formed by electrophoretic deposition in a cerium-containing sol on Alloy 800H, a 32Ni-20Cr steel, followed by firing in air at 1123 K was studied in oxidizing and mixed oxidizing/sulphidizing environments at elevated temperatures. In particular, the influence

  4. Stress Corrosion cracking susceptibility of reduced-activation martensitic steel F82H

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, Y. [Nuclear Energy and Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Ibaraki-ken (Japan); Jitsukawa, S.; Tsukada, T. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan)

    2007-07-01

    Full text of publication follows: For fusion power source in near future, supercritical water-cooled type blanket system was planned in Japan Atomic Energy Agency. The blankest system was designed by the present knowledge base and a reasonable extrapolation in material and design technology. Reduced-activation martensitic steel, F82H, is one of the blanket system structural materials. Therefore durability of the F82H for corrosion and stress corrosion cracking (SCC) is one of the concerns for this water-cooling concept of the blanket system. In this paper, SCC susceptibility of F82H was studied after heat treatments simulating post weld heat treatment (PWHT) or neutron-irradiation at 493 K to a dose level of 2.2 dpa. In order to evaluate SCC susceptibility of F82H, slow strain rate testing (SSRT) in high-purity, circulating water was conducted at 513-603 K in an autoclave. The strain rate was 1.0- 2.0x10{sup -7} s{sup -1}. Concentration of dissolved oxygen and hydrogen of the circulating water was controlled by bubbling with these gases. Specimens were heat treated after normalization at 1313 K for 40 min and water quenching. Some of the specimens were tempered at 873-1073 K for 1 h. Since the temperature control during PWHT in vacuum vessel by remote handling will be difficult, it is expected the tempering temperature will be different at place to place. Some specimens after tempering at 1033 K for 1 h were irradiated at 493 K to 2.2 dpa in Japan Research Reactor No.3 at Japan Atomic Energy Agency. The SSRT results showed the as-normalized specimens failed by IGSCC in oxygenated temperature water at 573 K. SSRT results of specimens with other tempering temperature conditions will be presented at conference. In irradiated specimen, IGSCC did not occur in oxygenated water at 5113-603 K. IGSCC also did not occur in hydrogenated water at 573 K. However TGSCC occurred in the irradiated specimen with a round notch (radius= {approx}0.2 mm) in oxygenated water at 573 K

  5. Improved sulphate removal rates at increased sulphide ...

    African Journals Online (AJOL)

    Improved sulphate removal rates at increased sulphide concentration in the sulphidogenic bioreactor. ... The results of three investigations operating a continuous reactor, a column reactor and batch-test reactors have shown that increased sulphide concentrations have resulted in improved biological sulphate reduction.

  6. The Study of Stress Corrosion Cracking on Alloy 600 C-Ring Samples by Polychromatic X-Ray Microdiffraction

    Science.gov (United States)

    Chao, Jing; Fuller, Marina L. Suominen; McIntyre, N. Stewart; Carcea, Anatolie G.; Newman, Roger C.; Kunz, Martin; Tamura, Nobumichi

    Microscopic strains associated with stress corrosion cracks have been investigated in stressed C-rings of Alloy 600 boiler tubing. Polychromatic X-ray Microdiffraction (PXM) was used to measure deviatoric strain tensors and the distribution of dislocations near cracks that had been propagated in electrochemically-accelerated corrosion tests. Stress corrosion cracking (SCC)-generated intergranular cracks were produced in two Alloy 600 specimens after 6h and 18h tests. The diffraction patterns and resultant strain tensors were mapped around the cracked area to a one micron spatial resolution. The strain tensor transverse to the crack growth direction showed tensile strain at the intergranular region just ahead of the crack tip for both specimens. Both cracks were found to follow grain boundary pathways that had the lowest angle of misorientation. Dislocation distributions within each grain were qualitatively obtained from the shapes of the diffraction spots and the effect of "hard" and "soft" grains on the crack pathway was explored for both 6h and 18h specimens.

  7. 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)

  8. 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.

  9. Temperature, stress, and corrosive sensing apparatus utilizing harmonic response of magnetically soft sensor element (s)

    Science.gov (United States)

    Grimes, Craig A. (Inventor); Ong, Keat Ghee (Inventor)

    2003-01-01

    A temperature sensing apparatus including a sensor element made of a magnetically soft material operatively arranged within a first and second time-varying interrogation magnetic field, the first time-varying magnetic field being generated at a frequency higher than that for the second magnetic field. A receiver, remote from the sensor element, is engaged to measure intensity of electromagnetic emissions from the sensor element to identify a relative maximum amplitude value for each of a plurality of higher-order harmonic frequency amplitudes so measured. A unit then determines a value for temperature (or other parameter of interst) using the relative maximum harmonic amplitude values identified. In other aspects of the invention, the focus is on an apparatus and technique for determining a value for of stress condition of a solid analyte and for determining a value for corrosion, using the relative maximum harmonic amplitude values identified. A magnetically hard element supporting a biasing field adjacent the magnetically soft sensor element can be included.

  10. Stress corrosion cracking mechanisms of Fe-based alloys in hydrogenated hot water

    Energy Technology Data Exchange (ETDEWEB)

    Coull, Z. [Univ. of Toronto, Dept. of Chemical Engineering and Applied Chemistry, Toronto, Ontario (Canada)]. E-mail: zcoull@chem-eng.utoronto.ca

    2006-07-01

    It is generally accepted that carbon steel resists Stress Corrosion Cracking (SCC) in hot water provided the oxygen content is low enough; however, isolated cracking events have occurred, apparently in fully reducing conditions, and these may or may not be true SCC. There are also occasional reports of SCC of austenitic stainless steel in reducing conditions where cold work may play a critical role. SCC though originally seen in sensitized material at oxidizing potentials persists to low potentials and in cold-worked but unsensitized material. We suspect from the literature that alloying with Ni introduces a susceptibility to SCC in reducing hot water as well as in caustic solution. Our hypothesis is that Ni causes SCC, and Cr retards it; so stainless steel has just enough Cr to protect against SCC under most conditions. We are examining this using model Fe-based materials and environments designed to separate the effects of different parameters. Early results suggest that Fe-Ni alloys and austenitic SS both undergo de-alloying and SCC in reducing caustic solutions. It is hypothesised that if these alloys are indeed susceptible to dealloying (and hence to SCC) in this environment then we can reasonably project that their behaviour in reducing, hot pure water may be similar. This is pertinent to understanding recent failures in high temperature, high pressure aqueous systems. As a first step we have investigated the surface reactions that occur in caustic solutions and in hot water. (author)

  11. SUSCEPTIBILITY OF ALLOY 690 TO STRESS CORROSION CRACKING IN CAUSTIC AQUEOUS SOLUTIONS

    Directory of Open Access Journals (Sweden)

    DONG-JIN KIM

    2013-02-01

    Full Text Available Stress corrosion cracking (SCC behaviors of Alloy 690 were studied in lead-containing aqueous alkaline solutions using the slow strain rate tension (SSRT tests in 0.1M and 2.5M NaOH with and without PbO at 315°C. The side and fracture surfaces of the alloy were then examined using scanning electron microscopy after the SSRT test. Microstructure and composition of the surface oxide layer were analyzed by using a field emission transmission electron microscopy, equipped with an energy dispersive X-ray spectroscopy. Even though Alloy 690 was almost immune to SCC in 0.1M NaOH solution, irrespective of PbO addition, the SCC resistance of Alloy 690 decreased in a 2.5M NaOH solution and further decreased by the addition of PbO. Based on thermodynamic stability and solubility of oxide, high Cr of 30wt% in the Alloy 690 is favorable to SCC in mild alkaline and acidic solutions whereas the SCC resistance of high Cr Alloy 690 is weakened drastically in the strong alkaline solution where the oxide is not stable any longer and solubility is too high to form a passive oxide locally.

  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. 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.

  14. 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.

  15. Mechanism of irradiation assisted stress corrosion crack initiation in thermally sensitized 304 stainless steel

    Science.gov (United States)

    Onchi, T.; Dohi, K.; Soneda, N.; Navas, Marta; Castaño, M. L.

    2005-04-01

    Thermally sensitized 304 stainless steels, irradiated up to 1.2 × 1021 n/cm2 (E > 1 MeV), were slow-strain-rate-tensile tested in 290 °C water containing 0.2 ppm dissolved oxygen (DO), followed by scanning and transmission electron microscopic examinations, to study mechanism of irradiation-assisted-stress-corrosion-crack (IASCC) initiation. Intergranular (IG) cracking behaviors changed at a border fluence (around 1 × 1020 n/cm2), above which deformation twinning were predominant and deformation localization occurred earlier with increasing fluence. The crack initiation sites tended to link to the deformation bands, indicating that the crack initiation may be brought about by the deformation bands interacted with grain boundaries. Thus the border fluence is equivalent to the IASCC threshold fluence for the sensitized material, although the terminology of IASCC is originally given to the non-sensitized materials without microstructural definition. The IASCC threshold fluence was found to change with irradiation conditions. Changes in IASCC susceptibility and IASCC threshold fluence with fluence and DO were further discussed.

  16. Hydrogen induced stress corrosion cracks initiation to propagation process of titanium alloys under the deep underground environments

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Gen.; Fukaya, Yuuichi; Akashi, Masatsune [Research Laboratory, Ishikawajima-Harima Heavy Industries, Co., Ltd. 1, Shin-Nakahara-Cho, Isogo-ku, Yokohama 235-8501 (Japan); Sawa, Shunsuke; Awano, Toshihiko; Hirano, Takashi; Kanno, Takeshi [Nuclear Division, Ishikawajima-Harima Heavy Industries, Co., Ltd. 1, Shin-Nakahara-Cho, Isogo-ku, Yokohama 235-8501 (Japan); Owada, Hitoshi; Kawahara, Ken-ichi; Asano, Hidekazu [Radioactive Waste Management Funding and Research Center, 4th floor, Mori Building No. 15, 2-8-10, Toranomon, Minato-ku, Tokyo (Japan)

    2004-07-01

    Overpacks for high-level trans-uranium (TRU) radioactive waste must be reliable for geological disposal for as long as 60,000 years. The composite overpacks composed of a corrosion resistant Ti-Pd alloy outer layer and a carbon steel inner layer should never be subject to crevice corrosion when stored in a deep underground environment. The presumed upper limit environment of TRU waste disposal was the groundwater originated from sea water, and 80 deg. C based on the radiation resolution. Ti-0.01Pd was chosen based on the empirical crevice corrosion temperature - chloride concentration map. The critical temperature of crevice corrosion was 92 deg. C at 0.6 mol/L [NaCl] solution based on E{sub R,CREV} measurements. The corrosion resistance of weld joint was equal to that of base material. From cathodic reaction on the titanium surface for maintaining the passivity, hydrogen might be generated. Hydrogen induced stress corrosion cracks have been shown to occur. The mean titanium-hydride thickness, H{sub d} and greatest crack depth for cross section, C{sub d} were measured after constant-current uni-axle constant load tensile test in 0.6 mol/L [NaCl] solution at 80 deg. C. Effects of electric charge density, Q, current density, i, temperature, T, pH were examined as parameter dependence. The electric current density, which copes with hydrogen occurrence speed decreased, the H{sub d} increased. Also H{sub d} is clearly seen to increase with Q when Q > 1 MC/m{sup 2}. No crack could be detected below Q{sub c} = 3.5 MC/m{sup 2}, and above the Q{sub c}, C{sub d} was initially increased with increases in Q. The equation C{sub d}({mu}m) = 7 x (Q(MC/m{sup 2}) - 3.5){sup 0.5} holds. Based on the details heat analysis of the radiation resolution during disposal, the temperature transition was computed. From the temperature dependence of electric current density for maintaining the passivity, the amount of electric charge density of 7.5 MC/m{sup 2} for 60,000 years was calculated

  17. Inhibition of Ce3+ on Stress Corrosion Crack of High Strength Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    LI Wen-ting

    2017-05-01

    Full Text Available The stress corrosion cracking (SCC susceptibility of 7A04 high strength aluminum alloy in 3.5% (mass fraction NaCl solution and the Ce3+ inhibition of SCC were investigated by slow stress rate test(SSRT, using constant current polarization, electrochemical noise (ECN and electrochemical impedance spectroscopy (EIS techniques. The inhibition mechanism of Ce3+ ions on the initiation and propagation of cracking was also analyzed. The results indicate that both anodic and cathodic galvanostatic polarizations can accelerate the SCC of 7A04, the former increases anodic dissolution but the latter accelerates hydrogen embrittlement of crack tip. SCC susceptibility of 7A04 can be reduced effectively by the addition of cerium ions, the fracture time is delayed and slowed down, but only during the initiation other than the propagation stage of cracking. Ce3+ ions can restrain the initiation of metastable pitting on the surface of 7A04 specimen, which therefore increase the induction time of the cracking since that the micro pits are usually the source of cracking.However, once the crack begins to propagate or the specimen is notched, the addition of cerium ions can rarely inhibit the cracking process. This is possibly attributed to that the radius of Ce3+ ion is too large to diffuse into the crack tip or it is hard to form protective CeO2 layer, Ce3+ ion therefore fails to rehabilitate the active alloy at the crack tip and further reduce the SCC developing rate of 7A04. SEM also indicates that the crack initiation of smooth 7A04 specimens is mainly induced by metastable or stable pits.

  18. Study of Hot Salt Stress Corrosion Crack Initiation of Alloy IMI 834 by using DC Potential Drop Method

    Energy Technology Data Exchange (ETDEWEB)

    Pustode, Mangesh D. [Bharat Forge Ltd., Pune (India); Dewangan, Bhupendra [Tata Steel, Jamshedpur (India); Raja, V. S. [Indian Institute of Technology Bombay, Mumbai (India); Paulose, Neeta; Babu, Narendra [Gas Turbine Research Establishment (GTRE), Bangalore (India)

    2016-10-15

    DC potential drop technique was employed during the slow strain rate tests to study the hot salt stress corrosion crack (HSSCC) initiation at 300 and 400 ℃. Threshold stresses for HSSCC initiation were found to about 88 % of the yield strength at both temperatures, but the time from crack initiation to final failure (Δtscc) decreased significantly with temperature, which reflects larger tendency for brittle fracture and secondary cracking. The brittle fracture features consisted of transgranular cracking through the primary α grain and discontinuous faceted cracking through the transformed β grains.

  19. In vivo and in vitro studies of the stress-corrosion cracking behavior of surgical implant alloys.

    Science.gov (United States)

    Bundy, K J; Marek, M; Hochman, R F

    1983-05-01

    Behavior of implant alloys exposed simultaneously to tensile stresses and corrosion environments has been examined. In the in vivo studies, a stainless steel and a titanium alloy exhibited cracklike features when loaded to the yield stress sigma y and implanted for 16 weeks. A cobalt-chromium alloy stressed beyond sigma y exhibited them in plastically deformed areas. A cobalt-chromium-nickel-molybdenum alloy appeared to be immune. In vitro samples loaded to various stress levels were immersed in Ringer's solution at 37 degrees C. Half of them were subjected to applied anodic potentials; the remaining control group was not. The applied potentials were dc potentials of magnitude similar to those generated by bioelectric effects. No attempt was made to duplicate time dependence or wave forms. Cracklike features were observed in the stainless steel and in the titanium alloy loaded to or beyond sigma y and polarized for 38 weeks. None were observed below sigma y. For the controls, no cracklike features were observed at any stress level after 53 1/2 weeks. Polarization measurements and potential versus time measurements were performed to study possible mechanisms for crack propagation. These investigations suggest that the in vivo corrosion environment is more severe than a 37 degrees C Ringer's solution because of the influence of both bioelectric effects and organic constituents. The implications of these studies for the performance of prosthetic devices is discussed.

  20. 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.

  1. Effect of solution treatment on stress corrosion cracking behavior of an as-forged Mg-Zn-Y-Zr alloy.

    Science.gov (United States)

    Wang, S D; Xu, D K; Wang, B J; Sheng, L Y; Han, E H; Dong, C

    2016-07-08

    Effect of solid solution treatment (T4) on stress corrosion cracking (SCC) behavior of an as-forged Mg-6.7%Zn-1.3%Y-0.6%Zr (in wt.%) alloy has been investigated using slow strain rate tensile (SSRT) testing in 3.5 wt.% NaCl solution. The results demonstrated that the SCC susceptibility index (ISCC) of as-forged samples was 0.95 and its elongation-to-failure (εf) was only 1.1%. After T4 treatment, the SCC resistance was remarkably improved. The ISCC and εf values of T4 samples were 0.86 and 3.4%, respectively. Fractography and surface observation indicated that the stress corrosion cracking mode for as-forged samples was dominated by transgranular and partially intergranular morphology, whereas the cracking mode for T4 samples was transgranular. In both cases, the main cracking mechanism was associated with hydrogen embrittlement (HE). Through alleviating the corrosion attack of Mg matrix, the influence of HE on the SCC resistance of T4 samples can be greatly suppressed.

  2. 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

  3. 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.

  4. Effect of W on stress corrosion cracking susceptibility of newly developed Ni-saving duplex stainless steels

    Science.gov (United States)

    Ha, Heon-Young; Lee, Tae-Ho; Kim, Sangshik

    2017-01-01

    Effect of W on stress corrosion cracking behavior (SCC) of Ni-saving duplex stainless steels (Fe18Cr6Mn3Mo0.4N (2.13, 5.27)W, in wt%) was investigated in 4 M NaCl solution using a slow strain rate test method. The change in the W content from 2.13 to 5.27 wt% marginally affected the tensile properties of the investigated DSSs. Alloying W clearly improved the pitting initiation resistance and repassivation tendency of the investigated alloys, but the SCC susceptibility was not remarkably decreased by addition of W. The slight enhancement in the SCC resistance of the alloy containing 5.27 wt% W was revealed to be correlated with the accelerated galvanic corrosion between the ferrite and austenite phases as a result of the W partitioning preferentially into the ferrite phase which could encourage the propagation of pitting.

  5. Characterizing the effect of creep on stress corrosion cracking of cold worked Alloy 690 in supercritical water environment

    Science.gov (United States)

    Zhang, Lefu; Chen, Kai; Du, Donghai; Gao, Wenhua; Andresen, Peter L.; Guo, Xianglong

    2017-08-01

    The effect of creep on stress corrosion cracking (SCC) was studied by measuring crack growth rates (CGRs) of 30% cold worked (CW) Alloy 690 in supercritical water (SCW) and inert gas environments at temperatures ranging from 450 °C to 550 °C. The SCC crack growth rate under SCW environments can be regarded as the cracking induced by the combined effect of corrosion and creep, while the CGR in inert gas environment can be taken as the portion of creep induced cracking. Results showed that the CW Alloy 690 sustained high susceptibility to intergranular (IG) cracking, and creep played a dominant role in the SCC crack growth behavior, contributing more than 80% of the total crack growth rate at each testing temperature. The temperature dependence of creep induced CGRs follows an Arrhenius dependency, with an apparent activation energy (QE) of about 225 kJ/mol.

  6. (IV) Oxide Corrosion in Oil Exploration

    African Journals Online (AJOL)

    Sulphide and Carbon lV Oxide in Oil Wells,. B. Eng Project, University of Port Harcourt,. 1988. Farshad, F.F and Garber, J.D. ~How to increase gas well production and temper corrosion; Part3-. Petroleum Engineering international, June l993. Stanford, A. Failure Analysis Isolates production - problem Petroleum Engineering ...

  7. Statistical analysis of measured growth rates of intergranular stress corrosion cracks; Statistisk analys av uppmaetta tillvaexthastigheter hos spaenningskorrosionssprickor (IGSCC)

    Energy Technology Data Exchange (ETDEWEB)

    Poern, K. [Poern Consulting, Nykoeping (Sweden)

    2000-09-01

    Intergranular Stress Corrosion Cracking (IGSCC) has been a serious problem within the nuclear power industry all over the world. Substantial efforts have been expended on research and experiments to enhance the understanding of the mechanisms behind this type of corrosion. An increased knowledge of such mechanisms is a condition precedent for preventing or at least reducing the problem. The crack growth rate has been the focus for analysis and estimation. As the data bases created in laboratory and other experiments have expanded there has been a growing pressure to use these data for the assessment of detected damage, even though the primary objective of these data has not always been to quantitatively determine the propagation rate of stress corrosion cracks. One exception here is the international project known as the 'SKI Round Robin', initiated by the Swedish Nuclear Power Inspectorate in order to be able to compare in a more controllable way various laboratories' measurements of IGSCC propagation rates. The aim of this study is to present methods for the statistical analysis of qualified data of crack propagation rates for varying material, environmental and stress conditions. A good knowledge of such connections as well as an understanding of the uncertainty in these connections can be used to evaluate the progress of already detected cracks and as basis for revision of existing regulation programmes. The Swedish Nuclear Power Inspectorate applies, at present, the principle of an 'upper bound curve' to describe the crack propagation rate as function of the stress conditions. In the long run another type of reasoning might appear as a result of a deeper statistical analysis of crack growth rates. To be able to conduct the statistical analysis for several parameter combinations a preliminary computer code has been developed based on Bayesian statistical methodology. In this report possible statistical models are discussed and

  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. Effect of Dynamic Change in Strain Rate on Mechanical and Stress Corrosion Cracking Behavior of a Mild Steel

    Science.gov (United States)

    Krishnan, Govinda; Varshney, A.; Parameswaran, Venkitanarayanan; Mondal, K.

    2017-05-01

    The current work analyzes the effect of the dynamic change in strain rate during tensile loading of a mild steel on its mechanical and stress corrosion behavior in 3.5 wt.% NaCl solution. The sample experiences high strain rate (10-2 s-1) up to 10, 15 and 20% of total deformation and then very low strain rate of 10-6 s-1 till fracture without any unloading in between. The behavioral characteristics of the steel under these circumstances are found to be different from that exhibited during complete loading till fracture both at high and slow strain rates separately. Total strain increases with the increase in the strain at which change in strain rate happens, and this is attributed to the generation of large number of dislocations at higher strain rate and subsequently release of dislocation at low strain rate during change over due to more time available for dynamic recovery. This observation is common for both in air and corrosive environment. One unique observation in this study is the higher total strain and lower strength observed during dynamic change in strain rate in the corrosive environment compared to that in air, which is attributed to the hydrogen-induced plasticity mechanism.

  11. 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

  12. Stress Corrosion Cracking Behavior of Fine-Grained AZ61 Magnesium Alloys Processed by Equal-Channel Angular Pressing

    OpenAIRE

    Qiuyuan Xie; Aibin Ma; Jinghua Jiang; Zhaojun Cheng; Dan Song; Yuchun Yuan; Huan Liu

    2017-01-01

    The effect of equal-channel angular pressing (ECAP) on stress corrosion cracking (SCC) behavior of a cast AZ61 Mg alloy was investigated in distilled water (DW) using the slow strain rate tensile test (SSRT) at a strain rate of 1 × 10−6 s−1. The fine-grained alloy after ECAP showed a greater SCC susceptibility but a higher ultimate tensile strength, compared with the as-cast counterpart. The results were attributed to refined grains, high-density dislocations and increased proportion of high-...

  13. 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

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  18. Detection of exhaled hydrogen sulphide gas in healthy human volunteers during intravenous administration of sodium sulphide.

    Science.gov (United States)

    Toombs, Christopher F; Insko, Michael A; Wintner, Edward A; Deckwerth, Thomas L; Usansky, Helen; Jamil, Khurram; Goldstein, Brahm; Cooreman, Michael; Szabo, Csaba

    2010-06-01

    Hydrogen sulphide (H(2)S) is an endogenous gaseous signaling molecule and potential therapeutic agent. Emerging studies indicate its therapeutic potential in a variety of cardiovascular diseases and in critical illness. Augmentation of endogenous sulphide concentrations by intravenous administration of sodium sulphide can be used for the delivery of H(2)S to the tissues. In the current study, we have measured H(2)S concentrations in the exhaled breath of healthy human volunteers subjected to increasing doses sodium sulphide in a human phase I safety and tolerability study. We have measured reactive sulphide in the blood via ex vivo derivatization of sulphide with monobromobimane to form sulphide-dibimane and blood concentrations of thiosulfate (major oxidative metabolite of sulphide) via ion chromatography. We have measured exhaled H(2)S concentrations using a custom-made device based on a sulphide gas detector (Interscan). Administration of IK-1001, a parenteral formulation of Na(2)S (0.005-0.20 mg kg(-1), i.v., infused over 1 min) induced an elevation of blood sulphide and thiosulfate concentrations over baseline, which was observed within the first 1-5 min following administration of IK-1001 at 0.10 mg kg(-1) dose and higher. In all subjects, basal exhaled H(2)S was observed to be higher than the ambient concentration of H(2)S gas in room air, indicative of on-going endogenous H(2)S production in human subjects. Upon intravenous administration of Na(2)S, a rapid elevation of exhaled H(2)S concentrations was observed. The amount of exhaled H(2)S rapidly decreased after discontinuation of the infusion of Na(2)S. Exhaled H(2)S represents a detectable route of elimination after parenteral administration of Na(2)S.

  19. Development of a method for studying the influence of stress state on the iodine-induced stress corrosion cracking of zirconium alloys

    Science.gov (United States)

    Mozzani, Nathanael; Auzoux, Quentin; Le Boulch, David; Andrieu, Eric; Blanc, Christine

    A method based on the exposure of notched tensile specimens to iodized methanol is investigated to study the influence of stress state on the iodine-induced stress corrosion cracking (I-SCC) of zirconium alloys. Based on uniaxial tensile tests at different strain rates, in air and at room temperature, an anisotropic viscoplastic behavior model was established. This model was successfully compared to a notched specimen tensile test where local strains were measured by digital image correlation. Moreover, two I-SCC experiments were designed, on a tensile test machine and with an autonomous bending device. Examinations of failure surfaces of smooth specimens and investigations of iodine location were undertaken. The intergranular aspect of the cracking was observed and no iodine was found outside open cracks. Model calculations with different specimen geometries confirmed the possibility of having different stress states and will be used to determine local mechanical fields at crack initiation sites after I-SCC tests.

  20. Effects of H2S/HS- on Stress Corrosion Cracking Behavior of X100 Pipeline Steel Under Simulated Sulfate-Reducing Bacteria Metabolite Conditions

    Science.gov (United States)

    Liu, Q.; Li, Z.; Liu, Z. Y.; Li, X. G.; Wang, S. Q.

    2017-04-01

    The effect of H2S/HS-, which simulates the main metabolites of sulfate-reducing bacteria (SRB), on the electrochemical and stress corrosion cracking (SCC) behaviors of X100 steel was investigated in a near-neutral solution. The results showed that different H2S/HS- contents mainly affected the cathodic process of X100 electrochemical corrosion. As the concentration of H2S/HS- increased, the corrosion potential was shifted negatively, the corrosion current density was considerably increased, and the corrosion rate was linearly increased. Different rust layers with shifting structures were formed under different conditions and had different effects on electrochemical behaviors. However, sulfide mainly promoted local corrosion processes. With the synergistic effects of stress and H2S/HS-, SCC susceptibility was considerably enhanced. The accelerated process of hydrogen evolution by sulfide was crucial in enhancing SCC processes. In brief, the trace H2S/HS- generated by SRB metabolites played a positive role in promoting SCC.

  1. 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.

  2. On the Stress Corrosion Cracking and Hydrogen Embrittlement Behavior of Austenitic Stainless Steels in Boiling Saturated Magnesium Chloride Solutions

    Directory of Open Access Journals (Sweden)

    Osama M. Alyousif

    2012-01-01

    Full Text Available The stress corrosion cracking (SCC and hydrogen embrittlement (HE behaviors for types 304, 310, and 316 austenitic stainless steels were investigated in boiling saturated magnesium chloride solutions using a constant load method under different conditions including test temperature, applied stress, and sensitization. Both of type 304 and type 316 stainless steels showed quite similar behavior characteristics, whereas type 310 stainless steel showed a different behavior. The time to failure (tf parameter was used among other parameters to characterize the materials behavior in the test solution and to develop a mathematical model for predicting the time to failure in the chloride solution. The combination of corrosion curve parameters and fracture surface micrographs gave some explanation for the cracking modes as well as an indication for the cracking mechanisms. On the basis of the results obtained, it was estimated that intergranular cracking was resulted from hydrogen embrittlement due to strain-induced formation of martensite along the grain boundaries, while transgranular cracking took place by propagating cracks nucleated at slip steps by dissolution.

  3. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-11-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  4. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-12-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  5. Analysis of Eddy Current Capabilities for the Detection of Outer Diameter Stress Corrosion Cracking in Small Bore Metallic Structures

    Science.gov (United States)

    Wincheski, Buzz; Williams, Phillip; Simpson, John

    2007-01-01

    The use of eddy current techniques for the detection of outer diameter damage in tubing and many complex aerospace structures often requires the use of an inner diameter probe due to a lack of access to the outside of the part. In small bore structures the probe size and orientation are constrained by the inner diameter of the part, complicating the optimization of the inspection technique. Detection of flaws through a significant remaining wall thickness becomes limited not only by the standard depth of penetration, but also geometrical aspects of the probe. Recently, an orthogonal eddy current probe was developed for detection of such flaws in Space Shuttle Primary Reaction Control System (PRCS) Thrusters. In this case, the detection of deeply buried stress corrosion cracking by an inner diameter eddy current probe was sought. Probe optimization was performed based upon the limiting spatial dimensions, flaw orientation, and required detection sensitivity. Analysis of the probe/flaw interaction was performed through the use of finite and boundary element modeling techniques. Experimental data for the flaw detection capabilities, including a probability of detection study, will be presented along with the simulation data. The results of this work have led to the successful deployment of an inspection system for the detection of stress corrosion cracking in Space Shuttle Primary Reaction Control System (PRCS) Thrusters.

  6. Stress Corrosion Cracking and Hydrogen Embrittlement of Thick Section High Strength Low Alloy Steel

    Science.gov (United States)

    1986-06-01

    corrosion cracking of alpha brass in ammoniacal copper sulfate and concluded that the experimental results were best supported by the film r.Apture...steel heat treatment was that a stronger product could be produced without resort to quenching with its attendant danger of warping and cracking; the

  7. stress corrosion cracking response of hand lay-up gry composites

    African Journals Online (AJOL)

    Dr Obe

    ASME, Applied. Mechanics Reviews, Vol. 47, pp. S66 -S76. 8. Heitz, E., Henkhaus, R., and Rahmel. A.,. (1992) Corrosion Science, an Experimental. Approach, Translated by Waterhouse, R.B., and Holmes, D.R., Ellis Horwood, London. 9. Wang, T.C., and Shih, C.F., (1992) Crack. Extension and Kinking in Laminates and.

  8. An Electrochemical Framework to Explain Intergranular Stress Corrosion Cracking in an Al-5.4%Cu-0.5%Mg-0.5%Ag Alloy

    Science.gov (United States)

    Little, D. A.; Connolly, B. J.; Scully, J. R.

    2001-01-01

    A modified version of the Cu-depletion electrochemical framework was used to explain the metallurgical factor creating intergranular stress corrosion cracking susceptibility in an aged Al-Cu-Mg-Ag alloy, C416. This framework was also used to explain the increased resistance to intergranular stress corrosion cracking in the overaged temper. Susceptibility in the under aged and T8 condition is consistent with the grain boundary Cu-depletion mechanism. Improvements in resistance of the T8+ thermal exposure of 5000 h at 225 F (T8+) compared to the T8 condition can be explained by depletion of Cu from solid solution.

  9. External stress-corrosion cracking of a 1.22-m-diameter type 316 stainless steel air valve

    Science.gov (United States)

    Moore, Thomas J.; Telesman, Jack; Moore, Allan S.; Johnson, Dereck F.; Kuivinen, David E.

    1993-01-01

    An investigation was conducted to determine the cause of the failure of a massive AISI Type 316 stainless steel valve which controlled combustion air to a jet engine test facility. Several through-the-wall cracks were present near welded joints in the valve skirt. The valve had been in outdoor service for 18 years. Samples were taken in the cracked regions for metallographic and chemical analyses. Insulating material and sources of water mist in the vicinity of the failed valve were analyzed for chlorides. A scanning electron microscope was used to determine whether foreign elements were present in a crack. On the basis of the information generated, the failure was characterized as external stress-corrosion cracking. The cracking resulted from a combination of residual tensile stress from welding and the presence of aqueous chlorides. Recommended countermeasures are included.

  10. 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

  11. Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Ziqing [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.; Toloczko, Mychailo [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.; Kruska, Karen [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.; Bruemmer, Stephen [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.

    2017-05-22

    Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 (UNS N06690) materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for either the 21% or 31%CW CLT specimens loaded at their yield stress after ~9,220 hours, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiation after 10,400 hours of exposure at constant stress intensity, which was resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and discusses their effects on crack initiation in CW alloy 690.

  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. 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.

  14. Evaluation of stress corrosion cracking susceptibility of stainless steel 304L with surface nanocrystallization by small punch test

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Tao; Chen, Peng [The Key Laboratory of Safety Science of Pressurized System, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Guan, Kaishu, E-mail: guankaishu@ecust.edu.cn [The Key Laboratory of Safety Science of Pressurized System, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

    2013-01-20

    In this study, the small punch test (SPT) was conducted to evaluate the stress corrosion cracking (SCC) susceptibility of stainless steel (SS) 304L with surface nanocrystallization (SNC) in 1 mol/L NaCl+0.5 mol/L HCl aq. The surface mechanical attrition treatment (SMAT) was applied to realize the SNC. The mechanical property and micro-structural evolutions of SS 304L induced by SMAT were investigated through optical microscope (OM), X-ray diffraction (XRD), micro-Vickers hardness and transmission electron microscopy (TEM). The grain size on the surface of the material was reduced to 30-100 nm. The SPT was conducted in both ambient air and corrosive solution. The results were investigated by OM and scanning electron microscopy (SEM), showing that in ambient air, the specimen with 30 min SMAT performed a higher yield strength and lower ductility than the solution annealed (SA) counterpart. The SS 304L without SMAT presented a transgranular SCC (TGSCC) mode in chloride solution. In contrast, the SNC 304L SS showed a higher SCC susceptibility with a typical intergranular SCC (IGSCC).

  15. 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.

  16. Effect of ferrite transformation on the tensile and stress corrosion properties of type 316 L stainless steel weld metal thermally aged at 873 K

    Science.gov (United States)

    Shaikh, H.; Khatak, H. S.; Seshadri, S. K.; Gnanamoorthy, J. B.; Rodriguez, P.

    1995-07-01

    This article deals with the effect of the microstructural changes, due to transformation of delta ferrite, on the associated variations that take place in the tensile and stress corrosion properties of type 316 L stainless steel weld deposits when subjected to postweld heat treatment at 873 K for prolonged periods (up to 2000 hours). On aging for short durations (up to 20 hours), carbide/ carbonitride was the dominant transformation product, whereas sigma phase was dominant at longer aging times. The changes in the tensile and stress corrosion behavior of the aged weld metal have been attributed to the two competitive processes of matrix softening and hardening. Yield strength (YS) was found to depend predominantly on matrix softening only, while sig-nificant changes in the ultimate tensile strength (UTS) and the work-hardening exponent, n, occurred due to matrix hardening. Ductility and stress corrosion properties were considerably affected by both factors. Fractographic observations on the weld metal tested for stress-corrosion cracking (SCC) indicated a combination of transgranular cracking of the austenite and interface cracking.

  17. 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.

  18. Determination of sulphides in cements by using potentiometry with a selective electrode of sulphides

    Directory of Open Access Journals (Sweden)

    Bernal, José Luis

    1988-03-01

    Full Text Available A procedure for the determination of sulphides attackable by HCI (1 :3 in cements by means of a potentiometric determination with a selective electrodo of sulphides, is proposed.

    Se propone un método para la determinación de sulfuros, basado en el ataque con HCI (1:3, destilación y posterior medida potenciométrica con un electrodo selectivo de sulfuros.

  19. Combustion synthesis of cadmium sulphide nanomaterials for ...

    Indian Academy of Sciences (India)

    Anion-doped cadmium sulphide nanomaterials have been synthesized by using combustionmethod at normal atmospheric conditions. Oxidant/fuel ratios have been optimized in order to obtain CdS with best characteristics. Formation of CdS and size of crystallite were identified by X-ray diffraction and confirmed by ...

  20. Combustion synthesis of cadmium sulphide nanomaterials for ...

    Indian Academy of Sciences (India)

    The observed enhanced photocatalytic activity of the CdS nanomaterials for the hydrogen production from water (2120 μmol/h) can be attributed to high crystallinity, low band gap and less exciton recombination due to the C and N doping. Keywords. Cadmium sulphide; combustion synthesis; anion doping; water splitting; ...

  1. Influence of irradiation, load history, and stress bi-axiality on initiation and propagation of stress corrosion cracks induced by iodine in zirconium alloys; Influence de l'irradiation, de l'historique de chargement et de la biaxialite des contraintes sur l'amorcage et le debut de la propagation des fissures de corrosion sous contrainte par l'iode des alliages de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Mozzani, N.; Auzoux, Q.; Le Boulch, D. [CEA Saclay, DEN, SEMI, 91 - Gif-sur-Yvette (France); Andrieu, E.; Blanc, Ch. [Universite de Toulouse, CIRIMAT, UPS/CNRS/INPT, ENSIACET, 31 - Toulouse (France); Trocellier, P. [CEA Saclay, DEN, SRMP, 91 - Gif-sur-Yvette (France)

    2010-03-15

    The authors present a research study aimed at the modelling of iodine-induced stress corrosion cracking of zirconium alloys. The aim is to develop a damage model coupled with the material mechanical behaviour, and which takes irradiation effects, load history and stress bi-axiality into account. The study comprises iodine-induced stress corrosion cracking tests of a non irradiated material and of a proton-irradiated material, a study of the mechanical behaviour and of the stress corrosion cracking behaviour of the irradiated material, and then the numerical modelling

  2. Potential high temperature corrosion problems due to co-firing of biomass and fossil fuels

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Vilhelmsen, T.; Jensen, S.A.

    2008-01-01

    Over the past few years, considerable high temperature corrosion problems have been encountered when firing biomass in power plants due to the high content of potassium chloride in the deposits. Therefore, to combat chloride corrosion problems cofiring of biomass with a fossil fuel has been....... However, the most significant corrosion attack was sulphidation attack at the grain boundaries of 18-8 steel after 3 years exposure. The corrosion mechanisms and corrosion rates are compared with biomass firing and coal firing. Potential corrosion problems due to co-firing biomass and fossil fuels...

  3. Potential high temperature corrosion problems due to co-firing of biomass and fossil fuels

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Vilhelmsen, T.; Jensen, S.A.

    2007-01-01

    Over the past years, considerable high temperature corrosion problems have been encountered when firing biomass in power plants due to the high content of potassium chloride in the deposits. Therefore to combat chloride corrosion problems co-firing of biomass with a fossil fuel has been undertaken...... significant corrosion attack was due to sulphidation attack at the grain boundaries of 18-8 steel after 3 years exposure. The corrosion mechanisms and corrosion rates are compared with biomass firing and coal firing. Potential corrosion problems due to co-firing biomass and fossil fuels are discussed....

  4. Stress Corrosion Cracking Behavior of Type 304 Stainless Steel Irradiated under Different Neutron Dose Rates at JMTR

    Science.gov (United States)

    Kaji, Yoshiyuki; Kondo, Keietsu; Aoyagi, Yoshiteru; Kato, Yoshiaki; Taguchi, Taketoshi; Takada, Fumiki; Nakano, Junichi; Ugachi, Hirokazu; Tsukada, Takashi; Takakura, Kenichi; Sakamoto, Hiroshi

    In order to investigate the effect of neutron dose rate on tensile properly and irradiation stress corrosion cracking (IASCC) behavior, crack growth rate (CGR) and, tensile tests and microstructure observation have been conducted with type 304 stainless steel specimens. The specimens were irradiated in high temperature water simulating boiling water reactor (BWR) environments up to about 1dpa with two different dose rates at the Japan Materials Testing Reactor (JMTR). While radiation hardening increased with the dose rate, CGR was not affected by the dose rate. Increase of the yield strength of the low dose rate specimens was caused by the increase of number density of Frank loops. Little difference of radiation-induced segregation at grain boundaries was observed in specimens irradiated by different dose rates. Furthermore, no dose rate effect on local plastic deformation behavior was found near crack tip in the crystal plasticity simulation

  5. Standard test method for determining whether gas-leak-detector fluid solutions can cause stress corrosion cracking of brass alloys

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers an accelerated test method for evaluating the tendency of gas leak detection fluids (LDFs) to cause stress corrosion cracking (SCC) of brass components in compressed gas service. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 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 to determine the applicability of regulatory limitations prior to use.

  6. Penetrative Internal Oxidation from Alloy 690 Surfaces and Stress Corrosion Crack Walls during Exposure to PWR Primary Water

    Science.gov (United States)

    Olszta, Matthew J.; Schreiber, Daniel K.; Thomas, Larry E.; Bruemmer, Stephen M.

    Analytical electron microscopy and three-dimensional atom probe tomography (ATP) examinations of surface and near-surface oxidation have been performed on Ni-30%Cr alloy 690 materials after exposure to high-temperature, simulated PWR primary water. The oxidation nanostructures have been characterized at crack walls after stress-corrosion crack growth tests and at polished surfaces of unstressed specimens for the same alloys. Localized oxidation was discovered for both crack walls and surfaces as continuous filaments (typically dislocations were oxidized in non-deformed materials, while the oxidation path appeared to be along more complex dislocation substructures in heavily deformed materials. This paper will highlight the use of high resolution scanning and transmission electron microscopy in combination with APT to better elucidate the microstructure and microchemistry of the filamentary oxidation.

  7. Stress Corrosion Cracking Behavior of Fine-Grained AZ61 Magnesium Alloys Processed by Equal-Channel Angular Pressing

    Directory of Open Access Journals (Sweden)

    Qiuyuan Xie

    2017-09-01

    Full Text Available The effect of equal-channel angular pressing (ECAP on stress corrosion cracking (SCC behavior of a cast AZ61 Mg alloy was investigated in distilled water (DW using the slow strain rate tensile test (SSRT at a strain rate of 1 × 10−6 s−1. The fine-grained alloy after ECAP showed a greater SCC susceptibility but a higher ultimate tensile strength, compared with the as-cast counterpart. The results were attributed to refined grains, high-density dislocations and increased proportion of high-angle grain boundaries induced by severe plastic deformation, as well as isolated fine β-phase particles transiting from net-like β-phase.

  8. The Dislocation Mechanism of Stress Corrosion Embrittlement in Ti-6Al-2Sn-4Zr-6Mo

    Science.gov (United States)

    Chapman, Tamara P.; Vorontsov, Vassili A.; Sankaran, Ananthi; Rugg, David; Lindley, Trevor C.; Dye, David

    2016-01-01

    An observation of the dislocation mechanisms operating below a naturally initiated hot-salt stress corrosion crack is presented, suggesting how hydrogen may contribute to embrittlement. The observations are consistent with the hydrogen-enhanced localized plasticity mechanism. Dislocation activity has been investigated through post-mortem examination of thin foils prepared by focused ion beam milling, lifted directly from the fracture surface. The results are in agreement with the existing studies, suggesting that hydrogen enhances dislocation motion. It is found that the presence of hydrogen in (solid) solution results in dislocation motion on slip systems that would not normally be expected to be active. A rationale is presented regarding the interplay of dislocation density and the hydrogen diffusion length.

  9. 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

  10. 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.

  11. 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.

  12. Post-hoc comparisons among iron electrode formulations based on bismuth, bismuth sulphide, iron sulphide, and potassium sulphide under strong alkaline conditions

    Science.gov (United States)

    Gil Posada, Jorge Omar; Hall, Peter J.

    2014-12-01

    Iron electrodes were prepared by hot-pressing iron-polyethylene based formulations on nickel foam stripes. NiFe cells were tested by using commercial nickel electrodes and our iron electrodes. Post-hoc comparisons were used to identify meaningful differences between iron electrode formulations (based upon bismuth, bismuth sulphate, potassium sulphide and iron sulphide as additives). Our results confirm that both bismuth sulphide and iron sulphide favour the process of charge/discharge of a NiFe cell. In addition, we have found that the use of metallic bismuth only marginally influences coulombic efficiency; likewise, the presence of the soluble bisulfide anion is not sufficient to increase coulombic efficiency. Finally, NiFe cells prepared with bismuth sulphide outperformed their iron sulphide counterparts.

  13. Estimation of Corrosion Fatigue Lives Based on the Variations of the Crack Lengths Distributions During Stress Cycling

    OpenAIRE

    Ishihara, Sotomi; Maekawa, Ichiro; Shiozawa, Kazuaki; Miyao, Kazyu

    1985-01-01

    Many small distributed cracks have been observed on the specimen during corrosion fatigue process, and the damage of corrosion fatigue is related to the behaviour of these distributed cracks. The distribution of crack lengths during corrosion fatigue was approximated well by the three parameter Weibull distribution under plane-bending fatigue tests of carbon steel in salt water. A method of estimation of corrosion fatigue lives was proposed. The crack initiation, crack growth behaviour and th...

  14. Grain boundary selective oxidation and intergranular stress corrosion crack growth of high-purity nickel binary alloys in high-temperature hydrogenated water

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, S. M.; Olszta, M. J.; Toloczko, M. B.; Schreiber, D. K.

    2018-02-01

    The effects of alloying elements in Ni-5at%X binary alloys on intergranular (IG) corrosion and stress corrosion cracking (SCC) have been assessed in 300-360°C hydrogenated water at the Ni/NiO stability line. Alloys with Cr or Al additions exhibited grain boundary oxidation and IGSCC, while localized degradation was not observed for pure Ni, Ni-Cu or Ni-Fe alloys. Environment-enhanced crack growth was determined by comparing the response in water and N2 gas. Results demonstrate that selective grain boundary oxidation of Cr and Al promoted IGSCC of these Ni alloys in hydrogenated water.

  15. Effects of hardness and test temperature on the stress-corrosion cracking susceptibility of carbon steel in simulated BWR environment; Koon koatsu sui kankyo ni okeru tansoko no oryoku fushokuware kanjusei ni oyobosu kodo, oyobi shiken ondo no eikyo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, G.; Akashi, M. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-03-15

    An SSRT test and a CBB test were carried out on carbon steel and heat treated materials applied with bead welding of single pass simulating fillet welding in oxygen-enriched high-temperature water environment, and the stress-corrosion cracking susceptibility was evaluated. Highly hard welding heat affected zones with Vickers hardness of more than 400 have grain boundary stress-corrosion cracking susceptibility. However, a structure whose high hardness has been realized by tempering treatment has no grain boundary stress-corrosion cracking susceptibility. In the SSRT test, stress-corrosion cracking fractured face rate rises with rising test temperature, resulting in stress-corrosion cracking susceptibility shown even at lower hardness. On the other hand in the CBB test, a large number of relatively shallow cracks are generated down to low hardness at temperatures below 190 degC, while the number of cracking occurrence decreases as the temperature rises. However, deep cracks increase. In the CBB test on tempered heat treatment materials, the fact that stress-corrosion cracking can occur in test pieces with Vickers hardness of 165, which is nearly the same as that for the base material, proves that no lower limit hardness exists practically in occurrence of stress-corrosion cracking in carbon steel. 13 refs., 12 figs., 2 tabs.

  16. 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.

  17. 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.

  18. Corrosion evaluation technology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Uh Chul; Han, Jeong Ho; Nho, Kye Ho; Lee, Eun Hee; Kim, Hong Pyo; Hwang, Seong Sik; Lee, Deok Hyun; Hur, Do Haeng; Kim, Kyung Mo

    1997-09-01

    A multifrequency ACPD system was assembled which can measure very small crack. Stress corrosion cracking test system with SSRT operating high temperature was installed. Stress corrosion cracking test of newly developed alloy 600 and existing alloy 600 was carried out in steam atmosphere of 400 deg C. No crack was observed in both materials within a test period of 2,000 hrs. Corrosion fatigue test system operating at high temperature was installed in which fatigue crack was measured by CDPD. Lead enhanced the SCC of the Alloy 600 in high temperature water, had a tendency to modify a cracking morphology from intergranular to transgranular. Pit initiation preferentially occurred at Ti-rich carbide. Resistance to pit initiation decreased with increasing temperature up to 300 deg C. Test loop for erosion corrosion was designed and fabricated. Thin layer activation technique was very effective in measuring erosion corrosion. Erosion corrosion of a part of secondary side pipe was evaluated by the Check Family Codes of EPRI. Calculated values of pipe thickness by Check Family Codes coincided with the pipe thickness measured by UT with an error of {+-} 20%. Literature review on turbine failure showed that failure usually occurred in low pressure turbine rotor disc and causes of failure are stress corrosion cracking and corrosion fatigue. (author). 12 refs., 20 tabs., 77 figs.

  19. Effectiveness of using pure copper and silver coupon corrosivity monitoring (CCM) metal strips to measure the severity levels of air pollutants in indoor and outdoor atmospheres

    CSIR Research Space (South Africa)

    Foax, LJ

    2008-10-01

    Full Text Available Severity levels of air pollutants rich in oxides, chlorides and sulphides were successfully measured in indoor and outdoor atmospheres using pure copper and silver coupon corrosivity monitoring (CCM) metal strips when the maximum exposure periods...

  20. Effects of Nitrogen and Tensile Direction on Stress Corrosion Cracking Susceptibility of Ni-Free FeCrMnC-Based Duplex Stainless Steels.

    Science.gov (United States)

    Ha, Heon-Young; Lee, Chang-Hoon; Lee, Tae-Ho; Kim, Sangshik

    2017-03-15

    Stress corrosion cracking (SCC) behavior of Ni-free duplex stainless steels containing N and C (Fe balance -19Cr-8Mn-0.25C-(0.03, 0.21)N, in wt %) was investigated by using a slow strain rate test (SSRT) in air and aqueous NaCl solution with different tensile directions, including parallel (longitudinal) and perpendicular (transverse) to the rolling direction. It was found that alloying N was effective in increasing the resistance to SCC, while it was higher along the longitudinal direction than the transverse direction. The SCC susceptibility of the two alloys was assessed based on the electrochemical resistance to pitting corrosion, the corrosion morphology, and the fractographic analysis.

  1. Effects of Nitrogen and Tensile Direction on Stress Corrosion Cracking Susceptibility of Ni-Free FeCrMnC-Based Duplex Stainless Steels

    Directory of Open Access Journals (Sweden)

    Heon-Young Ha

    2017-03-01

    Full Text Available Stress corrosion cracking (SCC behavior of Ni-free duplex stainless steels containing N and C (Febalance-19Cr-8Mn-0.25C-(0.03, 0.21N, in wt % was investigated by using a slow strain rate test (SSRT in air and aqueous NaCl solution with different tensile directions, including parallel (longitudinal and perpendicular (transverse to the rolling direction. It was found that alloying N was effective in increasing the resistance to SCC, while it was higher along the longitudinal direction than the transverse direction. The SCC susceptibility of the two alloys was assessed based on the electrochemical resistance to pitting corrosion, the corrosion morphology, and the fractographic analysis.

  2. Detection of exhaled hydrogen sulphide gas in rats exposed to intravenous sodium sulphide.

    Science.gov (United States)

    Insko, Michael A; Deckwerth, Thomas L; Hill, Paul; Toombs, Christopher F; Szabo, Csaba

    2009-07-01

    Sodium sulphide (Na(2)S) disassociates to sodium (Na(+)) hydrosulphide, anion (HS(-)) and hydrogen sulphide (H(2)S) in aqueous solutions. Here we have established and characterized a method to detect H(2)S gas in the exhaled breath of rats. Male rats were anaesthetized with ketamine and xylazine, instrumented with intravenous (i.v.) jugular vein catheters, and a tube inserted into the trachea was connected to a pneumotach connected to a H(2)S gas detector. Sodium sulphide, cysteine or the natural polysulphide compound diallyl disulphide were infused intravenously while the airway was monitored for exhaled H(2)S real time. Exhaled sulphide concentration was calculated to be in the range of 0.4-11 ppm in response to i.v. infusion rates ranging between 0.3 and 1.1 mg x kg(-1) x min(-1). When nitric oxide synthesis was inhibited with N(omega)-nitro-L-arginine methyl ester the amount of H(2)S exhaled during i.v. infusions of sodium sulphide was significantly increased compared with that obtained with the vehicle control. An increase in circulating nitric oxide using DETA NONOate [3,3-bis(aminoethyl)-1-hydroxy-2-oxo-1-triazene] did not alter the levels of exhaled H(2)S during an i.v. infusion of sodium sulphide. An i.v. bolus of L-cysteine, 1 g.kg(-1), and an i.v. infusion of the garlic derived natural compound diallyl disulphide, 1.8 mg x kg(-1) x min(-1), also caused exhalation of H(2)S gas. This method has shown that significant amounts of H(2)S are exhaled in rats during sodium sulphide infusions, and the amount exhaled can be modulated by various pharmacological interventions.

  3. Behavior of cold-worked AISI-304 steel in stress-corrosion cracking process: Microstructural aspects

    Science.gov (United States)

    Zeman, A.; Novotny, R.; Uca, O.; Krsjak, V.; Macak, J.; Debarberis, L.

    2008-10-01

    Austenitic stainless steel is one of the key structural materials for a wide-range of components for present nuclear power plants. Moreover, this type of steel is also foreseen as a key structural material in future reactor systems, the so-called Generation IV. However, for the successful application of these materials in new environmental conditions an integrated Research and Development program needs to be successfully completed. This work is focused to the evaluation of cold-worked AISI-304 stainless steel from 20 to 45% of cold-worked deformation by different spectroscopic techniques within the aim to study the microstructural characteristics. In particular, positron annihilation spectroscopy and small angle neutron scattering have been used for characterization of phase transformation and microstructural behavior. Furthermore, outcomes of corrosion properties of cold-worked AISI-304 stainless steel exposed for 100 and 500 h in super-critical water reactor conditions are correlated with the obtained results.

  4. DEVELOPMENT OF SOFTWARE SYSTEM FOR MONITORING OF STRESS CORROSION CRACKING OF THE PIPELINE UNDER TENSION

    Directory of Open Access Journals (Sweden)

    Z. K. Abaev

    2016-01-01

    Full Text Available The software and hardware development tendency, providing the automated monitoring and control of basic and auxiliary technological processes of gas transportation via system of main gas pipelines has been revealed. The article discusses the stages of creation of the software of system of monitoring corrosion cracking under tension (SCC. The new useful adequate regression models development determining the risk level of LCC is shown. A ranking sections algorithm of main gas pipeline (MG on the propensity to SCC is presented. Adequate developed regression equation determining the LCC risk level has been developed. To count the main gas pipeline lifetime the variable rank of the danger of SCC (RSCC on the basis of methods of fuzzy logic is proposed to use. Implementation of the fuzzy model was carried out using the graphical tools developed in MATLAB using the expansion pack Fuzzy Logic Toolbox. The working algorithm of developed program and the screen forms are presented.

  5. Influence of precracked specimen configuration and starting stress intensity on the stress corrosion cracking of 4340 steel

    Science.gov (United States)

    Lisagor, W. B.

    1984-01-01

    Experimental results are presented from a study of the effects of precracked specimen configuration and initial starting stress intensity on crack growth rate and threshold stress intensity, for both onset of cracking and crack arrest. Attention is given to AISI 4340 steel in a 3.5-percent NaCl solution, for configurations of a single edge-cracked specimen tested in cantilever bending under constant load, and a modified compact specimen bolt loaded to a constant deflection. The threshold stress intensity value determined was independent of specimen configuration, if the stress intensity value associated with the compact specimen is taken where the discontinuous break occurs in the velocity-stress intensity curve.

  6. Patterns of Macroinvertebrate and Fish Diversity in Freshwater Sulphide Springs

    Directory of Open Access Journals (Sweden)

    Ryan Greenway

    2014-09-01

    Full Text Available Extreme environments are characterised by the presence of physicochemical stressors and provide unique study systems to address problems in evolutionary ecology research. Sulphide springs provide an example of extreme freshwater environments; because hydrogen sulphide’s adverse physiological effects induce mortality in metazoans even at micromolar concentrations. Sulphide springs occur worldwide, but while microbial communities in sulphide springs have received broad attention, little is known about macroinvertebrates and fish inhabiting these toxic environments. We reviewed qualitative occurrence records of sulphide spring faunas on a global scale and present a quantitative case study comparing diversity patterns in sulphidic and adjacent non-sulphidic habitats across replicated river drainages in Southern Mexico. While detailed studies in most regions of the world remain scarce, available data suggests that sulphide spring faunas are characterised by low species richness. Dipterans (among macroinvertebrates and cyprinodontiforms (among fishes appear to dominate the communities in these habitats. At least in fish, there is evidence for the presence of highly endemic species and populations exclusively inhabiting sulphide springs. We provide a detailed discussion of traits that might predispose certain taxonomic groups to colonize sulphide springs, how colonizers subsequently adapt to cope with sulphide toxicity, and how adaptation may be linked to speciation processes.

  7. Strain energy density-distance criterion for the initiation of stress corrosion cracking of alloy X-750

    Energy Technology Data Exchange (ETDEWEB)

    Hall, M.M. Jr.; Symons, D.M.

    1996-05-01

    A strain energy density-distance criterion was previously developed and used to correlate rising-load K{sub c} initiation data for notched and fatigue precracked specimens of hydrogen precharged Alloy X-750. This criterion, which was developed for hydrogen embrittlement (HE) cracking, is used here to correlate static-load stress corrosion cracking (SCC) initiation times obtained for smooth geometry, notched and fatigue precracked specimens. The onset of SCC crack growth is hypothesized to occur when a critical strain, which is due to environment-enhanced creep, is attained within the specimen interior. For notched and precracked specimens, initiation is shown by analysis to occur at a variable distance from notch and crack tips. The initiation site varies from very near the crack tip, for highly loaded sharp cracks, to a site that is one grain diameter from the notch, for lower loaded, blunt notches. The existence of hydrogen gradients, which are due to strain-induced hydrogen trapping in the strain fields of notch and crack tips, is argued to be controlling the site for initiation of cracking. By considering the sources of the hydrogen, these observations are shown to be consistent with those from the previous HE study, in which the characteristic distance for crack initiation was found to be one grain diameter from the notch tip, independent of notch radius, applied stress intensity factor and hydrogen level.

  8. Arrhenius-Type Constitutive Model for High Temperature Flow Stress in a Nickel-Based Corrosion-Resistant Alloy

    Science.gov (United States)

    Wang, L.; Liu, F.; Cheng, J. J.; Zuo, Q.; Chen, C. F.

    2016-04-01

    Hot deformation behavior of Nickel-based corrosion-resistant alloy (N08028) was studied in compression tests conducted in the temperature range of 1050-1200 °C and the strain rate range of 0.001-1 s-1. The flow stress behavior and microstructural evolution were observed during the hot deformation process. The results show that the flow stress increases with deformation temperature decreasing and strain rate increasing, and that the deformation activation energy ( Q) is not a constant but increases with strain rate increasing at a given strain, which is closely related with dislocation movement. On this basis, a revised strain-dependent hyperbolic sine constitutive model was established, which considered that the "material constants" in the original model vary as functions of the strain and strain rate. The flow curves of N08028 alloy predicted by the proposed model are in good agreement with the experimental results, which indicates that the revised constitutive model can estimate precisely the flow curves of N08028 alloy.

  9. Photoconductivity of copper sulphide polycrystalline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, L.; Leon, M.; Arjona, F.; Garcia Camarero, E.

    1985-06-01

    The spectral response of the photoconductivity of copper sulphide polycrystalline films obtained by thermal evaporation has been studied. The phase content of the samples was determined by electron diffraction and the stoichiometry by potentiostatic methods. The electrical properties, resistivity and Hall effect, were determined by the Van der Pauw method. The photoconductivity quantum efficiency spectra show structures clearly characteristic of the phases chalcocite and djurleite. Chalcocite shows peaks at 900, 720 and 500 nm and Djurleite at 620 and 500 nm. Samples with less copper always show the 500 nm peak. This work shows that a peak at 500 nm appears in the photoconductivity spectral response of all copper sulphides studied: Cu(x)S (with x at least 1.89 and no more than 2). 22 references.

  10. Stress corrosion cracking in 3,5 NiCrMoV steel in a 403 K potential-PH diagram

    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

    3,5 NiCrMoV steel is used in low-pressure turbine rotors and discs. It has been pointed out that intergranular stress corrosion cracking may occur in this material in the wet region at temperatures of about 400 K. Accordingly, the authors focused on the environmental conditions under which stress corrosion cracking (SCC) occurs. A potential-pH diagram was used to investigate the region in which SCC occurs in the high strength materials that are particularly susceptible to SCC. The investigation found that SCC is initiated in this material not only in the high caustic region but in the neutral region as well. The investigation also found that initiation and propagation were accelerated in dissolved oxygen environments with increased chemical potential in the neutral region. Since careful observation of the starting point of cracks has shown that corrosion pits trigger SCC, subsequent immersion tests under constant potential were conducted. The results showed that corrosion pits are generated at the high potential range. These results led to the development of an acceleration test environment for laboratory to determine the susceptibility of SCC in field turbine disc and rotor materials. (author)

  11. Standard Practice for Use of Mattsson's Solution of pH 7.2 to Evaluate the Stress- Corrosion Cracking Susceptibility of Copper-Zinc Alloys

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This practice covers the preparation and use of Mattsson's solution of pH 7.2 as an accelerated stress-corrosion cracking test environment for brasses (copper-zinc base alloys). The variables (to the extent that these are known at present) that require control are described together with possible means for controlling and standardizing these variables. 1.2 This practice is recommended only for brasses (copper-zinc base alloys). The use of this test environment is not recommended for other copper alloys since the results may be erroneous, providing completely misleading rankings. This is particularly true of alloys containing aluminum or nickel as deliberate alloying additions. 1.3 This practice is intended primarily where the test objective is to determine the relative stress-corrosion cracking susceptibility of different brasses under the same or different stress conditions or to determine the absolute degree of stress corrosion cracking susceptibility, if any, of a particular brass or brass component ...

  12. High temperature corrosion during biomass firing: improved understanding by depth resolved characterisation of corrosion products

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2015-01-01

    The high temperature corrosion of an austenitic stainless steel (TP 347H FG), widely utilised as a superheater tube material in Danish power stations, was investigated to verify the corrosion mechanisms related to biomass firing. KCl coated samples were exposed isothermally to 560 degrees C...... changes within the near surface region (covering both the deposit and the steel surface). Such cross-section analysis was further complemented by plan view investigations (additionally involving X-ray diffraction) combined with removal of the corrosion products. Improved insights into the nature...... of the corrosion products as a function of distance from the deposit surface were revealed through this comprehensive characterisation. Corrosion attack during simulated straw-firing conditions was observed to occur through both active oxidation and sulphidation mechanisms....

  13. Effect of aluminum and yttrium doping on zinc sulphide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Swati, E-mail: sharma.swati1507@gmail.com; Kashyap, Jyoti; Kapoor, A. [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi-110021 (India); Gupta, Shubhra [Sri Venkateswara College, University of Delhi, New Delhi-110021 (India); Natasha [Maharaja Agrasen College, University of Delhi-110053 (India)

    2016-05-06

    In this work, pristine and doped Zinc Sulphide (ZnS) nanoparticles have been synthesized via chemical co-precipitation method. ZnS nanoparticles have been doped with Aluminium (Al) and Yttrium (Y) with doping concentration of 5wt% each. The structural and optical properties of the as prepared nanoparticles have been studied using X-Ray diffraction (XRD) technique and Photoluminescence spectroscopy. Average grain size of 2-3nm is observed through the XRD analysis. Effect of doping on stress, strain and lattice constant of the nanoparticles has also been analyzed. Photoluminescence spectra of the as prepared nanoparticles is enhanced due to Al doping and quenched due to Y doping. EDAX studies confirm the relative doping percentage to be 3.47 % and 3.94% by wt. for Al and Y doped nanoparticles respectively. Morphology of the nanoparticles studied using TEM and SEM indicates uniform distribution of spherical nanoparticles.

  14. Effect of aluminum and yttrium doping on zinc sulphide nanoparticles

    Science.gov (United States)

    Sharma, Swati; Kashyap, Jyoti; Gupta, Shubhra; Natasha, Kapoor, A.

    2016-05-01

    In this work, pristine and doped Zinc Sulphide (ZnS) nanoparticles have been synthesized via chemical co-precipitation method. ZnS nanoparticles have been doped with Aluminium (Al) and Yttrium (Y) with doping concentration of 5wt% each. The structural and optical properties of the as prepared nanoparticles have been studied using X-Ray diffraction (XRD) technique and Photoluminescence spectroscopy. Average grain size of 2-3nm is observed through the XRD analysis. Effect of doping on stress, strain and lattice constant of the nanoparticles has also been analyzed. Photoluminescence spectra of the as prepared nanoparticles is enhanced due to Al doping and quenched due to Y doping. EDAX studies confirm the relative doping percentage to be 3.47 % and 3.94% by wt. for Al and Y doped nanoparticles respectively. Morphology of the nanoparticles studied using TEM and SEM indicates uniform distribution of spherical nanoparticles.

  15. 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

  16. Thermodynamic study of metal sulphides conversion to oxides in hydrometallurgy

    Directory of Open Access Journals (Sweden)

    J. Bocan

    2017-01-01

    Full Text Available This paper presents thermodynamic study of the conversion of metal sulphides to oxides of the CuAg sulphide concentrate as a final product after mechano-chemical leaching of tetrahedrite. The conversion of sulphides to oxides is carried out by oxidation leaching in NaOH solution. The thermodynamic calculation was performed for the sulphide concentrate containing the following sulphides: CuS, CuFeS2, FeS, Sb2S3, As2S3, Bi2S3 and HgS. Based on the change of Gibbs free energy (ΔG° and the equilibrium constant (K, conversion of metal sulphides to oxides from the qualitative assessment of the chemical reaction can occur as the result of the thermodynamic reaction abilities.

  17. 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.)

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

    Science.gov (United States)

    1972-01-01

    inhibitors as a second-line defense in case the coating is breached. When flaws do appear, there is danger that crackiihg may be enhanced through hydrogen... lait iiiay keep thle At fes:l iiiuch hiigher t1.1 a 1 clcrilicd. lfite Illiafijoi\\Al utile Iililtitatise stress coIlooi data reported in tisl’ paper Iike

  19. 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.

  20. Stress-corrosion fatigue-crack growth in a Zr-based bulk amorphousmetal

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, V.; Ritchie, R.O.

    2005-09-21

    Electrochemical and mechanical experiments were conducted to analyze the environmentally-influenced cracking behavior of a bulk amorphous metal, Zr41.2Ti13.8Cu12.5Ni10Be22.5. This study was motivated by a scientific interest in mechanisms of fatigue-crack propagation in an amorphous metal, and by a practical interest in the use of this amorphous metal in applications that take advantage of its unique properties, including high specific strength, large elastic strains and low damping. The objective of the work was to determine the rate and mechanisms of subcritical crack growth in this metallic glass in an aggressive environment. Specifically, fatigue-crack propagation behavior was investigated at a range of stress intensities in air and aqueous salt solutions by examining the effects of loading cycle, stress-intensity range, solution concentration, anion identity, solution de-aeration, and bulk electrochemical potential. Results indicate that crack growth in aqueous solution in this alloy is driven by a stress-assisted anodic reaction at the crack tip. Rate-determining steps for such behavior are reasoned to be electrochemical, stress-dependent reaction at near-threshold levels, and mass transport at higher (steady-state) growth rates.

  1. CHANGE IN THE MECHANICAL PROPERTIES AND STRESS CORROSION CRACKING UNDER MATERIAL OF METALWARE TENSION OF A CLAMP-FORMING MACHINE ARROW

    Directory of Open Access Journals (Sweden)

    L. K. Polishchuk

    2015-02-01

    Full Text Available Purpose. The aim is to study the effects of conditions and duration of working of structures arrows of a clamp-forming machine on mechanical properties of the material and its stress corrosion cracking under tension. It is necessary to improve the accuracy of resources analysis of boom metalwares of lifting and transporting machines. Methodology. Samples for experimental investigations were made of the elements of arrow continued exploited clamp-forming machine where there were major work stress. Centers of greatest efforts in elements of arrows constructions were determined in its 3D model in the analysis of the stress cards by finite element method. Experimental studies were performed at the facility UVP-6, which determined the characteristics of strength and ductility of samples of two types by means of tensile strain, speed 10-5 s-1 and 10-6 s-1 in air and in the environment of synthetic rain. Metallographic studies were performed on a scanning electron microscope. Findings. Experimental studies found that after long-term operation of arrow of clamp-forming machine material of its most loaded elements changed due to characteristics of strength and ductility. At joint action of corrosion environment and the greatest stress on the surface of the material expressions, point defects are appeared. They are concentrators of local mechanical stress, which reduce the resource construction elements of the arrow. Originality. 1. Firstly set patterns of changes in the mechanical properties of continued operated metal construction of arrow of clamp-forming machine made of St. 3; 2. Received further developed methodology for remaining resource estimation continued operated of metal boom lifting and shipping the machine by taking into account joint action vibration and dynamic loads and corrosive environments. Practical value. Determination the residual resource of continued operated boom lifting and transporting metal machines should be carried out

  2. The effect of alloy composition on the mechanism of stress-corrosion cracking of titanium alloys in aqueous environments

    Science.gov (United States)

    Wood, R. A.; Boyd, J. D.; Williams, D. N.; Jaffee, R. I.

    1972-01-01

    A detailed study was made of the relation between the size distribution of Ti3Al particles in a Ti-8Al alloy and the tensile properties measured in air and in saltwater. The size distribution of Ti3Al was varied by isothermal aging for various times at temperatures in the range 770 to 970 K (930 to 1290 F). The aging kinetics were found to be relatively slow. Quantitative measurements of the particle coarsening rate at 920 K (1200 F) showed good agreement with the predicted behavior for coarsening controlled by matrix diffusion, and suggested that the specific free energy of the Ti3Al alpha interface in negligible small. In all cases, the Ti3Al particles were sheared by the glide dislocations. It was concluded that there is a definite correlation between the presence of deformable Ti3Al particles and an alloy's susceptibility to aqueous stress corrosion cracking. Furthermore, the appearance of the surface slip lines and the dislocation substructure in deformed specimens suggest that the specific effect of the Ti3Al particles is to cause a nonhomogeneous planar slip character and an enhanced chemical potential of the slip bands.

  3. 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.

  4. Development of Eddy Current Technique for the Detection of Stress Corrosion Cracking in Space Shuttle Primary Reaction Control Thrusters

    Science.gov (United States)

    Wincheski, Buzz; Simpson, John; Koshti, Ajay

    2006-01-01

    A recent identification of stress corrosion cracking in the Space Shuttle Primary Reaction Control System (PRCS) thrusters triggered an extensive nondestructive evaluation effort to develop techniques capable of identifying such damage on installed shuttle hardware. As a part of this effort, specially designed eddy current probes inserted into the acoustic cavity were explored for the detection of such flaws and for evaluation of the remaining material between the crack tip and acoustic cavity. The technique utilizes two orthogonal eddy current probes which are scanned under stepper motor control in the acoustic cavity to identify cracks hidden with as much as 0.060 remaining wall thickness to the cavity. As crack growth rates in this area have been determined to be very slow, such an inspection provides a large safety margin for continued operation of the critical shuttle hardware. Testing has been performed on thruster components with both actual and fabricated defects. This paper will review the design and performance of the developed eddy current inspection system. Detection of flaws as a function of remaining wall thickness will be presented along with the proposed system configuration for depot level or on-vehicle inspection capabilities.

  5. Stress Corrosion Cracking Susceptibility of 304L Substrate and 308L Weld Metal Exposed to a Salt Spray

    Directory of Open Access Journals (Sweden)

    Chia-Hao Hsu

    2017-02-01

    Full Text Available 304 stainless steels (SS were considered as the materials for a dry storage canister. In this study, ER (Electrode Rod 308L was utilized as the filler metal for the groove and overlay welds of a 304L stainless steel substrate, which was prepared via a gas tungsten arc-welding process in multiple passes. The electron backscatter diffraction (EBSD map was used to identify the inherent microstructures in distinct specimens. U-bend and weight-loss tests were conducted by testing the 304L substrates and welds in a salt spray containing 5 wt % NaCl at 80 °C to evaluate their susceptibility to stress corrosion cracking (SCC. Generally, the weight loss of the ER 308L deposit was higher than that of the 304L substrate in a salt spray in the same sample-prepared condition. The dissolution of the skeletal structure in the fusion zone (FZ was responsible for a greater weight loss of the 308L deposit, especially for the cold-rolled and sensitized specimen. Cold rolling was detrimental and sensitization after cold rolling was very harmful to the SCC resistance of the 304L substrate and 308L deposit. Overall, the SCC susceptibility of each specimen was correlated with its weight loss in each group.

  6. Laser shock peening without coating induced residual stress distribution, wettability characteristics and enhanced pitting corrosion resistance of austenitic stainless steel

    Science.gov (United States)

    Prabhakaran, S.; Kulkarni, Aniket; Vasanth, G.; Kalainathan, S.; Shukla, Pratik; Vasudevan, Vijay K.

    2018-01-01

    Low energy laser shock peening without coating (LSPwC) was conducted on AISI 304 austenitic stainless steel specimens with varying pulse densities or overlapping. Highest magnitude of compressive residual stress (CRS) was achieved for an optimized pulse density of 2500 pulses/cm2 (75% overlapping). The 2-D and 3-D topographical analysis were indicative of the fact that controlled roughening of the surface was achieved after the LSPwC process. After the LSPwC process, the hydrophilic unpeened surface was converted into the hydrophobic surface, thus decreasing the wettability characteristics of the surface. The X-ray diffraction (XRD) results reveal that there is a beginning of the martensite transformation and the rise in the intensity value of the peaks after LSPwC indicates the presence of compressive residual stresses induced in the specimen. The optical microscope and high-resolution transmission electron microscope results provided evidence of grain refinement and deformation induced refinement features such as multidirectional mechanical twinning, dislocations lines, micro shear cells and stacking faults in the near and sub-surface areas. The average hardness value of the LSPwC specimens was found to be increased by 28% more than the untreated specimen. The potentiodynamic polarization revealed that there was a considerable amount of increase in the pitting corrosion resistance after the LSPwC process, thus, supporting to extend the fatigue life of the specimen. The electrochemical impedance spectroscopic (EIS) analysis depicts that the LSPwC process supports the formation of the strong passivation layer in 3.5% NaCl solution.

  7. 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

  8. Microstructure, mechanical properties and stress corrosion cracking of Al–Zn–Mg–Zr alloy sheet with trace amount of Sc

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Pan, Qinglin, E-mail: pql1964@126.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiming; Huang, Zhiqi [Guangdong Fenglu Aluminum Co., Ltd, Foshan 528133 (China); Yin, Zhimin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2015-11-25

    Microstructural and property evolution of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy sheet during its preparation were investigated in detail by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Vickers micro-hardness test and room temperature tensile test. Stress corrosion cracking (SCC) behavior of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy under different heat treatments was studied using slow strain rate test. The results showed that serious dendritic segregation existed in as-cast condition. The suitable homogenization treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was 470 °C/24 h. After homogenization treatment, dissoluble Zn and Mg enriched non-equilibrium phases dissolved into α-Al matrix completely. The suitable solid solution-aging treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was solution treated at 470 °C for 60 min, followed by water quenching and then aged at 120 °C for 24 h. Under this aging temper, the grain structures were composed of sub-grains, η′ phases and nanometer-sized, spherical Al{sub 3}(Sc, Zr) particles. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The improved corrosion resistance from increasing aging temperature or prolonging aging time was due to the discontinuous η precipitates along the grain boundary and the high area fraction of GBPs. The main strengthening mechanisms of Al–Zn–Mg–0.10%Sc–0.10%Zr alloy are precipitation strengthening derived from η′ precipitates, dispersion strengthening, sub-grain strengthening and grain refinement caused by coherent Al{sub 3}(Sc, Zr) particles. - Highlights: • The suitable homogenization treatment of the alloy has been identified. • Evolution of microstructure and mechanical properties is investigated. • Strengthening mechanisms of the alloy has been established. • The basic mechanism has

  9. Effect of residual stress relaxation by means of local rapid induction heating on stress corrosion cracking behavior and electrochemical characterization of welded Ti-6Al-4V alloy under slow strain rate test

    Science.gov (United States)

    Liu, Yan; Tang, Shawei; Liu, Guangyi; Sun, Yue; Hu, Jin

    2017-05-01

    In this study, a welded Ti-6Al-4V alloy was treated by means of local rapid induction heating in order to relax the residual stress existed in the weldment. The welded samples were heat treated at the different temperatures. The stress corrosion cracking behavior and electrochemical characterization of the as-welded samples before and after the post weld heat treatment as a function of residual stress were investigated. Electrochemical impedance spectroscopy measurements of the samples under slow strain rate test were performed in a LiCl-methanol solution. The results demonstrated that the residual stress in the as-welded sample was dramatically reduced after the post weld heat treatment, and the residual stress decreased with the increase in the heat treatment temperature. The stress corrosion cracking susceptibility and electrochemical activity of the as-welded sample were significantly reduced after the heat treatment due to the relaxation of the residual stress, which gradually decreased with the decreasing value of the residual stress distributed in the heat treated samples.

  10. Sulphide Microchemistry and Hydrothermal Fluid Evolution in Quartz ...

    African Journals Online (AJOL)

    2008-06-14

    Jun 14, 2008 ... was calculated from the final ice melting temperatures while the Th CO2 was used to calculate CO2 densities. (Roedder 1984). OBSERVATIONS AND. INTERPRETATIONS. Sulphide microchemistry. The results of the microprobe analyses of the main sulphide minerals in the Batouri gold district are.

  11. Indicator minerals as guides to base metal sulphide mineralisation ...

    Indian Academy of Sciences (India)

    Zn-bearing minerals that act as indicator minerals for base metal sulphide mineralization from the Proterozoic Betul Belt,central India with special emphasis on their genetic significance have been discussed.Sulphide mineralisation is hosted by the felsic volcanic rocks and has similarities with volcanic-hosted massive ...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Stress corrosion in silica optical fibers: Review of fatigue testing procedures

    Science.gov (United States)

    Severin, Irina; Borda, Claudia; Dumitrache-Rujinski, Alexandru; Caramihai, Mihai; Abdi, Rochdi El

    2018-02-01

    The expected lifetime of optical fibers used either in telecommunication technologies or smart applications are closely related to the chemical reaction on the silica network. Due to the manufacturing processes or the handling procedures, the flaws spread on the fiber surface are inherently present. The aging mechanism is assumed to enlarge or to extend these flaws. Based on systematic experiments one may notice that water may induce a certain curing effect. Silica optical fibers have been aged in water; series of samples have been subjected to overlapped stretching or bending. Other series have been subjected to overlapped aging effect of microwaves and hot water. Finally, samples were submitted to dynamic tensile testing. The Weibull's diagram analysis shows mono or bimodal dispersions of flaws on the fiber surface, but the polymer coating appears vital for fiber lifetime. While humidity usually affects the fiber strength, the series of testing has revealed that in controlled conditions of chemical environment and controlled applied stress, fiber strength may be increased. A similar effect may be obtained by external factors such as microwaves or previous elongation, too.

  18. Stress Corrosion Cracking Behavior of Stainless Steel 304 in the Sulfuric Acid Environment Due to Prestrain

    Directory of Open Access Journals (Sweden)

    Mohammad Badaruddin

    2010-10-01

    Full Text Available The aim of  research is to investigate the effect of prestrain  on the stress corossion cracking behavior of AISI 304 stainless steel in the sulfuric acid of 10% concentration  under the static cantilever loading according to ASTM E-1681 standart. The specimen of 304 Stainless steel was strain up over the yield strength until reaching the uniform strain of 5% and 10% using servopulser UTM 9506 under the  displacement control of 0,3 mm/sec. The results of test  show that the prestrain of 5%  specimen is faster  failure than both  of  the prestrain of 10% and unprestrain specimen. It was caused by both of the decrease of ductility and  the short   incubation period. The change of deflection could be only recorded under  the loading 20% of yield strength. Intergranular crack was the prestrain of 10% specimen under the static loading of  616 MPa. Whereas,  for the prestrain of 10% specimen transgranular crack  was found under the static loading of 554,4 MPa. The prestrain of 5% specimen was mixed crack  under the static loading of 369.6 MPa. Higher dislocation density on the layer surface due to plastic deformation with increasing the percentage of pre-strain, so more difficult hydrogen diffused into the crack tip. Consequently, The incubation period can be prolonged.

  19. Effect of irradiation on the stress corrosion cracking behavior of Alloy X-750 and Alloy 625

    Energy Technology Data Exchange (ETDEWEB)

    Mills, W.J.; Lebo, M.R.; Kearns, J.J.; Hoffman, R.C.; Korinko, J.J.; Luther, R.F.; Sykes, G.B.

    1993-10-01

    In-reactor testing of bolt-loaded precracked and as-notched compact tension specimens was performed in 360{degrees}C water to determine effect of irradiation on SCC of Condition HTH and Condition BH Alloy X-750 and age-hardened Alloy 625. Variables were stress intensity factor (K{sub I}) level, fluence, grade of HTH material, prestraining and material chemistry. Effects of irradiation on high temperature SCC and the rapid cracking that occurs during cooldown below 150{degrees}C were characterized. Significant degradation in the in-reactor SCC resistance of HTH material was observed at initial K{sub I} levels above 30 MPa{radical}m and fluences greater than 10{sup 19} n/cm{sup 2} (E > 1 MeV). A small degradation in SCC resistance of HTH material was observed at low fluences (<10{sup 16} n/cm{sup 2}). As-notched specimens displayed less degradation in SCC resistance than precracked specimens. Prestraining greatly improved in-flux and out-of-flux SCC resistance of HTH material, as little or no SCC was observed in precracked specimens prestrained 20 to 30%, whereas extensive cracking was observed in nonprestrained specimens. Condition HTH heats with low boron (10 ppM or less) had improved in-reactor SCC resistance compared to heats with high and intermediate boron (>20 ppM). Age-hardened Alloy 625 exhibited superior in-reactor SCC behavior compared to HTH material as no crack extension occurred in any of the precracked Alloy 625 specimens tested at initial K{sub I} levels up to 80 MPa{radical}m.

  20. Hot corrosion of the B2 nickel aluminides

    Science.gov (United States)

    Ellis, David L.

    1993-01-01

    The hot corrosion behavior of the B2 nickel aluminides was studied to determine the inherent hot corrosion resistance of the beta nickel aluminides and to develop a mechanism for the hot corrosion of the beta nickel aluminides. The effects of the prior processing of the material, small additions of zirconium, stoichiometry of the materials, and preoxidation of the samples were also examined. Additions of 2, 5, and 15 w/o chromium were used to determine the effect of chromium on the hot corrosion of the beta nickel aluminides and the minimum amount of chromium necessary for good hot corrosion resistance. The results indicate that the beta nickel aluminides have inferior inherent hot corrosion resistance despite their excellent oxidation resistance. Prior processing and zirconium additions had no discernible effect on the hot corrosion resistance of the alloys. Preoxidation extended the incubation period of the alloys only a few hours and was not considered to be an effective means of stopping hot corrosion. Stoichiometry was a major factor in determining the hot corrosion resistance of the alloys with the higher aluminum alloys having a definitely superior hot corrosion resistance. The addition of chromium to the alloys stopped the hot corrosion attack in the alloys tested. From a variety of experimental results, a complex hot corrosion mechanism was proposed. During the early stages of the hot corrosion of these alloys the corrosion is dominated by a local sulphidation/oxidation form of attack. During the intermediate stages of the hot corrosion, the aluminum depletion at the surface leads to a change in the oxidation mechanism from a protective external alumina layer to a mixed nickel-aluminum spinel and nickel oxide that can occur both externally and internally. The material undergoes extensive cracking during the later portions of the hot corrosion.

  1. Effect of plasticity on stress corrosion cracking rate of X-52 pipeline steel in near-neutral pH environment

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Eadie, R.L.; Luo, J.L. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2005-07-01

    Near-neutral stress corrosion cracking (SCC) in pipeline steel occurs through the interaction of adequate stresses, susceptible pipe material and a potent environment. However, there is uncertainty regarding the roles played by key factors such as stress and stress induced plastic deformation. Most SCC failures in Canadian pipelines occur as longitudinal cracking, driven by hoop stress caused by the operating pressure within oil and gas pipelines. Plastic deformation from bending or rolling is typically encountered during the manufacture and assembly of pipeline components. The other situations which cause localized micro-plastic deformation at stress levels below the yield stress of the steel include the surface layer of the pipe wall thickness which can deform before the bulk of the wall thickness, and the cyclic-loading which can cause steels to exhibit micro-plastic strains at nominal stress levels where plastic strains would not be expected. Hydrogen-assisted plasticity can also occur which can delay the arrest of primary creep and increase the susceptibility of SCC. This study focused on longitudinal cracking and the effect of plastic deformation on the susceptibility of X-52 pipeline steel to near-neutral pH SCC. The study revealed that the plastic deformation of material will decrease the resistance to near-neutral pH SCC. 13 refs., 3 tabs., 8 figs.

  2. A comparison of constant-load and constant-deflection stress-corrosion tests on precracked DCB specimens. [Double Cantilever Beam

    Science.gov (United States)

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

    1978-01-01

    A comparison is made between measurements of stress-corrosion crack propagation made by a constant-load procedure and by a constant-deflection procedure. Precracked double cantilever beam specimens from 7075 aluminum alloy plate were used. The specimens were oriented in such a way that cracking would begin in the short-transverse plane and would propagate in the rolling direction. The specimens were subjected to a buffered salt-chromate solution and a 3.6% synthetic sea salt solution. The measurements were made optically with a binocular microscope. Stress intensities and crack lengths were calculated and crack velocities were obtained. Velocity was plotted against the average calculated stress intensity. Good agreement between the two methods was found for the salt-chromate solution, although some descrepancies were noted for the artificial sea salt solution.

  3. 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.

  4. An evaluation of carbon steel corrosion under stagnant seawater conditions.

    Science.gov (United States)

    Lee, Jason S; Ray, Richard I; Lemieux, Edward J; Falster, Alexander U; Little, Brenda J

    2004-01-01

    Corrosion of 1020 carbon steel coupons in natural seawater over a 1-year period was more aggressive under strictly anaerobic stagnant conditions than under aerobic stagnant conditions as measured by weight loss and instantaneous corrosion rate (polarization resistance). Under oxygenated conditions, a two-tiered oxide layer of lepidocrocite/goethite formed. The inner layer was extremely tenacious and resistant to acid cleaning. Under anaerobic conditions, the corrosion product was initially a non-tenacious sulphur-rich corrosion product, mackinawite, with enmeshed bacteria. As more sulphide was produced the mackinawite was transformed to pyrrhotite. In both aerobic and anaerobic exposures, corrosion was more aggressive on horizontally oriented coupons compared to vertically oriented samples.

  5. 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, ...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Corrosion control under thermal insulation and fireproofing

    Energy Technology Data Exchange (ETDEWEB)

    Delahunt, J.F.

    1982-02-01

    Corrosion occurring on carbon steel which is protected by thermal insulation (mineral wool, fiberglass, foam glass, calcium silicate, phenolics, and polyurethanes) or by fireproofing material (concrete or gunite) is discussed. Examples are given and illustrated of corrosion in refineries, petrochemical plants, and pipelines which have been thermally insulated or fireproofed. Four corrosion mechanisms have been identified and are discussed. The promoting action of chlorides as well as the pH effect or corrosion are described and it is concluded that the corrosion under thermal insulation follows two patterns. Further, organic cellular foams (polyurethanes and phenolics) are shown to accelerate corrosive action. Stress corrosion cracking of stainless steel under thermal insulation is described and the effect of improper design/application is stressed. Specific measures to control corrosion are discussed for concrete fireproofing and thermal insulation. (MJJ)

  11. 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

  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. Production of volatile Sulphides in Allium Porrum cell cultures

    OpenAIRE

    Asghari Gh.R; Lockwood GB; Houshfar Gh.A "

    2002-01-01

    Production of volatile sulphides in cell cultures of Allium porrum is described. Allium porrum calluses were initiated from whole seedlings. The high growth rate of Allium porrum callus was achived in Murashige and Skoog media containing only 1 ppm 2, 4-Dichlorophenoxy acetic acid. The routine method of solvent extraction of volatile sulphides was used for Allium porrum and the concentrated extract was subjected to capillary GC and GC-MS. Dipropyl disulphide and 4-methyl thiazolethanol were i...

  14. 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.

  15. Low-energy EDX--a novel approach to study stress corrosion cracking in SUS304 stainless steel via scanning electron microscopy.

    Science.gov (United States)

    Meisnar, Martina; Lozano-Perez, Sergio; Moody, Michael; Holland, James

    2014-11-01

    Intergranular stress corrosion cracking (IGSCC) in type SUS304 stainless steels, tested under pressurized water reactor (PWR) primary water conditions, has been characterized with unprecedented spatial resolution using scanning electron microscopy (SEM) and novel low-energy (∼3 kV) energy dispersive X-ray spectroscopy (EDX). An advancement of the large area silicon drift detector (SDD) has enhanced its sensitivity for X-rays in the low-energy part of the atomic spectrum. Therefore, it was possible to operate the SEM at lower accelerating voltages in order to reduce the interaction volume of the beam with the material and achieve higher spatial resolution and better signal-to-noise ratio. In addition to studying the oxide chemistry at the surface of intergranular stress corrosion cracks, the technique has proven capable of resolving Ni enrichment ahead of some crack tips. Active cracks could be distinguished from inactive ones due to the presence of oxides in the open crack and Ni-rich regions ahead of the crack tip. Furthermore, it has been established that SCC features can be better resolved with low-energy (3 kV) than high-energy (12 kV) EDX. The low effort in sample preparation, execution and data analysis makes SEM the ideal tool for initial characterization and selection of the most important SCC features such as dominant cracks and interesting crack tips, later to be studied by transmission electron microscopy (TEM) and atom probe tomography (APT). Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Microstructure, local mechanical properties and stress corrosion cracking susceptibility of an SA508-52M-316LN safe-end dissimilar metal weld joint by GTAW

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Hongliang; Zhu, Ruolin [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049 (China); Zhang, Zhiming [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Jianqiu, E-mail: wangjianqiu@imr.ac.cn [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Han, En.-Hou.; Ke, Wei [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Su, Mingxing [Shanghai Research Center for Weld and Detection Engineering Technique of Nuclear Equipment, Shanghai 201306 (China)

    2016-07-04

    The microstructure, local mechanical properties and local stress corrosion cracking susceptibility of an SA508-52M-316LN domestic dissimilar metal welded safe-end joint used for AP1000 nuclear power plant prepared by automatic gas tungsten arc welding was studied in this work by optical microscopy, scanning electron microscopy (with electron back scattering diffraction and an energy dispersive X-ray spectroscopy system), micro-hardness testing, local mechanical tensile testing and local slow strain rate tests. The micro-hardness, local mechanical properties and stress corrosion cracking susceptibility across this dissimilar metal weld joint vary because of the complex microstructure across the fusion area and the dramatic chemical composition change across the fusion lines. Briefly, Type I boundaries and Type II boundaries exist in 52Mb near the SA508-52Mb interface, a microstructure transition was found in SA508 heat affected zone, the residual strain and grain boundary character distribution changes as a function of the distance from the fusion boundary in 316LN heat affected zone, micro-hardness distribution and local mechanical properties along the DMWJ are heterogeneous, and 52Mw-316LN interface has the highest SCC susceptibility in this DMWJ while 316LN base metal has the lowest one.

  17. Prevention: Stress corrosion. Insulation of freezing pipes of a GMP-multifunction plant at Degussa, Trostberg; Vorbeugung: Spannungsrisskorrosion. Daemmung von Kaelteleitungen einer GMP-Mehrfunktionsanlage bei Degussa, Trostberg

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-08-29

    Stress corrosion can occure by halogeneous or strong alcalic solutions and by simultaneous influence of stress and moisture. The G+H Isolierung Muenchen uses the halogen free insulating material NH/Armaflex for the insulation of freezing pipelines, operating in the new GMP (Good Manufacturing Practice) plant at Trostberg. After the installation the insulated pipelines were layered by aluminium coatings. (GL) [German] Bei der Daemmung von Edelstahlleitungen besteht ein erhoehtes Risiko eines selektiven Korrosionsangriffs, z.B. in Form einer Spannungsrisskorrosion. Ausgeloest wird diese Korrosionsform durch halogenhaltige oder stark alkalische Loesungen und sie tritt beim gleichzeitigen Zusammenwirken von Zugspannungen und Feuchtigkeit auf. Fuer die Daemmung von Kaelteleitungen aus hochlegiertem Edelstahl einer neuen GMP (Good Manufacturing Practice)-Anlage am Standort Trostberg setzte G+H Isolierung Muenchen den halogenfreien Daemmstoff NH/Armaflex ein. Teilweise wurden die gedaemmten Leitungen anschliessend alukaschiert. (orig.)

  18. Systematic Review of Uit Parameters on Residual Stresses of Sensitized AA5456 and Field Based Residual Stress Measurements for Predicting and Mitigating Stress Corrosion Cracking

    Science.gov (United States)

    2014-03-01

    sensitization EBSD electron backscatter diffraction ECAE equal channel angular extrusion FIB-SEM focused ion beam, scanning electron microscope GMAW gas...induce compressive stresses [40, 43]. Other SPD methods include equal channel angular extrusion ( ECAE ), accumulative roll bonding (ARB), and...pp. 414–419, 2003. [50] Lambda Technologies Group . (2012). Low plasticity burnishing. [Online]. Available: http://www.lambdatechs.com/low

  19. 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.

  20. Palladium sulphide (PdS) films as a new thermoelectric sulphide compound

    Energy Technology Data Exchange (ETDEWEB)

    Ares, J.R.; Diaz-Chao, P.; Clamagirand, J.; Macia, M.D.; Ferrer, I.J.; Sanchez, C. [Universidad Autonoma de Madrid (Spain). Lab. de Materiales de Interes en Energias Renovables

    2010-07-01

    Palladium sulphide (PdS) films have been prepared by direct sulphuration of 20 nm thick palladium films at different temperatures (200 C < T < 450 C). Sulphurated films exhibit an unique crystalline phase: PdS. Seebeck coefficient and electrical resistivity of these films are between -110 and -150 {mu}V/K and {proportional_to} 0.08 to 0.8 {omega}cm depending on the sulphuration temperature. Negative sign of Seebeck coefficient indicates an n type conduction in all films. Discussion is focused on the influence of atomic ratio between sulphur and palladium as well as impurities arising from the substrate on transport properties. (orig.)

  1. 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)

  2. The influence of Sr on the microstructure, degradation and stress corrosion cracking of the Mg alloys - ZK40xSr.

    Science.gov (United States)

    Chen, Lianxi; Bin, Yuanhong; Zou, Wenqi; Wang, Xiaojian; Li, Wei

    2017-02-01

    In the present work, new magnesium (Mg) alloys (Mg-4Zn-0.6Zr-xSr, x=0, 0.4, 0.8, 1.2, 1.6wt%; ZK40xSr) were prepared and studied as potential biodegradable materials. The influence of strontium (Sr) addition on the properties of the new Mg alloys was investigated, which included microstructure, corrosion degradation, and the stress corrosion cracking (SCC) susceptibility. The average grain size of the ZK40Sr was approximately 100µm, which was significantly smaller than that of ZK40 alloy without Sr (402.3±40.2µm). The size of grain boundaries precipitates in the ZK40xSr alloys gradually increased with the increase of Sr content. The grain boundaries finally showed a continuously distribution and net-like shape. The degradation test showed that the average degradation rate of the ZK40xSr alloys increased with the increase of Sr addition. In the case of Mg-4Zn-0.6Zr, the degradation rate was 2.2mgcm-2day-1, which was lower than that of Mg-4Zn-0.6Zr-1.6Sr (4.93mgcm-2day-1). When the ZK40xSr alloys were immersed in m-SBF, the rod-like Sr-contained hydroxyapatite (HA) substance was detected, which was known to enhance cell growth around bone implants. The fracture surfaces of the as-cast Mg-4Zn-0.6Zr-1.6Sr were shown intergranular stress corrosion cracking (IGSCC) patterns. The increase of SCC susceptibility of the higher Sr ZK40xSr alloys was attributed to the increase of micro-galvanic corrosion between the α-Mg and the grain boundaries precipitates. The SCC susceptibility values were ≈0.13 and ≈0.41 for the Mg-4Zn-0.6Zr-0.4Sr and the Mg-4Zn-0.6Zr-1.6Sr, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. 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.)

  4. Laboratory model to evaluate the influence of stress and corrosion in the formation of non-carious cervical lesions

    OpenAIRE

    Leal, Noélia Maria de Sousa; Benigno, Maria Ivone Mendes; Silva, Juscelino Lopes; Pedrosa,Simone Soares; ALVES, Eliane Bemerguy; Ballester,Rafael Yagüe

    2014-01-01

    Objective: To conceive and test a laboratory model that simulates the multifactorial etiology of non-carious cervical lesions. The model enables researchers to assess the pathological process with increasing levels of complexity, focusing on tension and corrosion. The model is aimed at clarifying the mechanisms that lead to the development of these lesions. Methods: Specimens were manufactured from bovine incisors cut into 18 × 3 × 3 mm sticks, with a notch in the cervical region facing the p...

  5. Corrosion inhibition..

    African Journals Online (AJOL)

    ABSTRACT. The corrosion inhibition of carbon steel in 3% de-aerated NaCl acidic solution with amine—fatty acid corrosion inhibitor, KI384, .... reduction reaction causing no decrease in the limiting current density of that process. On the .... value when compared to the base solution. This provides a support to the physical ...

  6. 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…

  7. 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.

  8. Corrosion of iron steel under sulphate reducing conditions: application to deep geological disposal of high-level radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    El Hajj, H.; Abdelouas, A.; Grambow, B. [Nantes Univ., SUBATECH, UMR 6457 IN2P3/CNRS-Ecole des Mines de Nantes, 44 - Nantes (France)

    2009-07-01

    Full text of publication follows: We investigated the corrosion of the steel P235 under disposal conditions of high-level radioactive waste in argillite. The objective was to study the role of sulphate-reducing bacteria (SRB) indigenous to argillite that may develop under excess of hydrogen produced by steel corrosion in groundwater flowing through argillite. Batch and column experiments were conducted in serum bottles/diffusion cells with coupons of P235 steel, argillite and synthetic argillite water. This system provided enough nutrients to grow SRB's within two weeks with corrosion of the steel and formation of iron sulphides as corrosion products. The results of the weight loss method showed that the steel corrosion seems to be faster in the presence of SRB's in comparison to sterilized runs. The mineralogical identification of iron sulphides, observed and analysed with the scanning electron microscope, will be conducted with Raman spectroscopy and X-ray diffraction. The corrosion mechanism will be determined by studying steel cross sections and surface observations after removal of corrosion layer. Experiments with diffusion cells are under way and the collected outlet solutions show a decrease of sulphate concentration with production of sulphide ions. The results to be obtained with the steel corroded in the cell will be presented at the end of the run planned for few months.

  9. 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]).

  10. Comparison of Equations for Predicting Primary Water Stress Corrosion Crack Growth Rates in a Surge Nozzle Weld on the Hot Leg Side

    Energy Technology Data Exchange (ETDEWEB)

    Na, Kyung Hwan; Yun, Eun Sub; Park, Young Sheop [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2009-10-15

    Nickel-based austenitic alloys such as Alloy 600 and the weld metals Alloy 82, and 182 have been employed extensively in nuclear power plants (NPPs) in Korea. During the construction of NPPs, it was widely believed that these alloys have high corrosion resistance as well as good mechanical properties. However, since the 2000s, the occurrence of primary water stress corrosion cracking (PWSCC) has been reported in conjunction with these alloys in oversea NPPs and this has received international attention due to its potential effect on the structural integrity of piping in reactor coolant system. Under these circumstances, PWSCC growth rate studies of Alloy 600/82/182 have become important issues, and many studies have been carried out as a result. The Electric Power Research Institute (EPRI) in the United States proposed two crack growth rate (CGR) equations for PWSCC in its MRP-21, and MRP-115 reports. On the other hand, the Nuclear Regulatory Commission (NRC) recommended one equation for this purpose. In the present work, one instance of the initiation of an imaginary crack was assumed to exist at the inner surface of a surge nozzle weld on the hot leg side first. Subsequently, the CGRs were estimated for this initiated crack according to the MRP-21, MRP-115, and NRC equations. Finally, a comparison of the equations was made through their CGR results mainly in terms of their degree of conservatisms.

  11. 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...

  12. Microstructure, Residual Stress, Corrosion and Wear Resistance of Vacuum Annealed TiCN/TiN/Ti Films Deposited on AZ31

    Directory of Open Access Journals (Sweden)

    Haitao Li

    2016-12-01

    Full Text Available Composite titanium carbonitride (TiCN thin films deposited on AZ31 by DC/RF magnetron sputtering were vacuum annealed at different temperatures. Vacuum annealing yields the following on the structure and properties of the films: the grain grows and the roughness increases with an increase of annealing temperature, the structure changes from polycrystalline to single crystal, and the distribution of each element becomes more uniform. The residual stress effectively decreases compared to the as-deposited film, and their corrosion resistance is much improved owing to the change of structure and fusion of surface defects, whereas the wear-resistance is degraded due to the grain growth and the increase of surface roughness under a certain temperature.

  13. Influence of alloyed Sc and Zr, and heat treatment on microstructures and stress corrosion cracking of Al–Zn–Mg–Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yunjia [School of Materials Science and Engineering, Central South University, Hunan, Changsha 410083 (China); Pan, Qinglin, E-mail: csupql@163.com [School of Materials Science and Engineering, Central South University, Hunan, Changsha 410083 (China); Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Hunan, Changsha 410083 (China); Li, Mengjia; Huang, Xing; Li, Bo [School of Materials Science and Engineering, Central South University, Hunan, Changsha 410083 (China)

    2015-01-05

    Stress corrosion cracking (SCC) behavior of Al–Zn–Mg–Cu alloys with different Sc, Zr contents and heat treatments was studied using slow strain rate test. Grain boundary microstructures were identified by transmission electron microscopy (TEM) and statistical analysis. It was found that the SCC resistance of alloys is improved by increasing Sc, Zr contents and aging degree. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The results reveal that for Al–Zn–Mg–Cu–0.25Sc–0.10Zr (wt%) alloy with different aging degrees, hydrogen induced cracking dominates the SCC when the area fraction of GBPs is relatively low. For peak-aged Al–Zn–Mg–Cu alloy and Al–Zn–Mg–Cu–0.10Sc–0.10Zr (wt%) alloy, anodic dissolution dominates the SCC when the area fraction of GBPs is sufficiently high.

  14. Enhanced stress corrosion cracking resistance and electrical conductivity of a T761 treated Al-Zn-Mg-Cu alloy thin plate

    Science.gov (United States)

    Chen, Xu; Zhai, Sudan; Gao, Di; Liu, Ye; Xu, Jing; Liu, Yang

    2018-01-01

    The stress corrosion cracking (SCC) behavior, electrical conductivity and mechanical properties of an Al-Zn-Mg-Cu alloy pre-stretched thin plate for wing skin were researched in this paper. The microstructures and SCC fracture surfaces of the alloy treated at different conditions were characterized by transmission electron microscopy, optical microscopy and scanning electron microscopy. Results indicated that with the increasing of aging temperature, the electrical conductivity and the elongation increased greatly, while the strength decreased gradually which were closely associated with the type and morphology of the precipitates. Compared with the T6 treated alloy, the SCC resistance of the T761 treated Al-Zn-Mg-Cu alloy was improved greatly. The SCC behavior of the T6 treated alloy was dominated by anodic dissolution theory, whereas the hydrogen induced cracking controlled the fracture behavior of the T761 treated alloy which was influenced by the morphology of grain boundary precipitates in this investigated alloy.

  15. Fractures in high-strength bolts due to hydrogen induced stress corrosion. Causes and corrective actions; Brueche hochfester Schrauben infolge wasserstoffinduzierter Spannungsrisskorrosion. Ursachen und Abhilfemassnahmen

    Energy Technology Data Exchange (ETDEWEB)

    Hoche, Holger; Oechsner, Matthias [Technische Univ. Darmstadt (Germany). Zentrum fuer Konstruktionswerkstoffe

    2017-03-15

    Delayed brittle fractures of high-strength bolts of the strength class 10.9 are presented, taking the example of three damage cases. The respective damage mechanisms could be attributed to hydrogen induced stress corrosion which was caused, in turn, by hydrogen absorption during operation. The examples were chosen with a particular focus on the material condition's susceptibility which explains the cause for the occurrence of the damage mechanism. However, in only one of the three cases the susceptibility was evident and could be explained by violations of normative specifications and an unfavorable material choice. Whereas in the two other examples, only slight or no deviations from the standards and/or regulations could be found. The influencing parameters that caused the damage, those that further promoted the damage, as well as possible corrective actions are discussed taking into account the three exemplary damage cases.

  16. Effect of Hydrogen Charging on the Stress Corrosion Behavior of 2205 Duplex Stainless Steel Under 3.5 wt.% NaCl Thin Electrolyte Layer

    Science.gov (United States)

    Zhao, Tianliang; Liu, Zhiyong; Hu, Shanshan; Du, Cuiwei; Li, Xiaogang

    2017-05-01

    The effect of hydrogen charging on the stress corrosion cracking (SCC) behavior of 2205 duplex stainless steel (DSS) under 3.5 wt.% NaCl thin electrolyte layer was investigated on precharged samples through hydrogen determination, electrochemical measurement, and slow strain rate tensile test. Results show that hydrogen charging weakens the passive film without inducing any obvious trace of localized anodic dissolution. Therefore, hydrogen charging increases the SCC susceptibility of 2205 DSS mainly through mechanism of hydrogen embrittlement rather than mechanism of localized anodic dissolution. 2205 DSS shows a more susceptibility to hydrogen under the TEL when hydrogen charging current density (HCCD) is between 20 and 50 mA cm-2. The increasing trend is remarkable when hydrogen charging current density increases from 20 to 50 mA cm-2 and fades after 50 mA cm-2.

  17. Application of nano-sized TiO2 as an inhibitor of stress corrosion cracking in the steam generator tube materials.

    Science.gov (United States)

    Kim, Kyung Mo; Lee, Eun Hee; Kim, Uh Chul; Choi, Byung Seon

    2010-01-01

    Several chemicals were studied to suppress the damage due to a stress corrosion cracking (SCC) of the steam generator (SG) tubes in nuclear power plants. SCC tests were carried out to investigate the performance of TiO2 on several types of SG tube materials. The SCC tests were conducted by using an m-RUB specimen in a 10% NaOH solution at a temperature of 315 degrees C. The test with the addition of TiO2 showed a decrease in the SCC rate for the SG tubing materials. In order to improve the inhibition property in a crevice of TiO2, a sonochemical technique was applied to reduce the size of the TiO2 particle. From the SCC tests with the RUB specimen, the SG tube materials showed an enhanced cracking resistance with the addition of nano-sized TiO2 and the surface property was also changed.

  18. Stress Corrosion Crack Growth Rate Testing and Analytical Electron Microscopy of Alloy 600 as a Function of Pourbaix Space and Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    N. Lewis; S.A. Attanasio; D.S. Morton; G.A. Young

    2000-10-04

    Stress corrosion crack (SCC) growth rate tests and analytical electron microscopy (AEM) studies were performed over a broad range of environments and heat treatments of Alloy 600. This effort was conducted to correlate bulk environmental conditions such as pH and electrochemical potential (EcP) with the morphology of the SCC crack. Development of a library of AEM morphologies formed by SCC in different environments is an important step in identifying the conditions that lead to SCC in components. Additionally, AEM examination of stress corrosion cracks formed in different environments and microstructures lends insight into the mechanism(s) of stress corrosion cracking. Testing was conducted on compact tension specimens in three environments: a mildly acidic oxidizing environment containing sulfate ions, a caustic environment containing 10% NaOH, and hydrogenated near-neutral buffered water. Additionally, stress corrosion cracking testing of a smooth specimen was conducted in hydrogenated steam. The following heat treatments of Alloy 600 were examined: mill annealed at 980 C (near-neutral water), mill annealed at 1010 C (steam), sensitized (acid and caustic), and mill annealed + healed to homogenize the grain boundary Cr concentration (caustic). Crack growth rate (CGR) testing showed that sensitized Alloy 600 tested in the mildly acidic, oxidizing environment containing sulfate ions produced the fastest cracking ({approx} 8.8 {micro}m/hr at 260 C), and AEM examination revealed evidence of sulfur segregation to the crack tip. The caustic environment produced slower cracking ({approx} 0.4 {micro}m/hr at 307 C) in the mill annealed + healed heat treatment but no observed cracking in the sensitized condition. In the caustic environment, fully oxidized carbides were present in the crack wake but not ahead of the crack tip. In near-neutral buffered water at 338 C, the CGR was a function of dissolved hydrogen in the water and exhibited a maximum (0.17 {micro}m/hr) near the

  19. Effects of long-term thermal aging on the stress corrosion cracking behavior of cast austenitic stainless steels in simulated PWR primary water

    Science.gov (United States)

    Li, Shilei; Wang, Yanli; Wang, Hui; Xin, Changsheng; Wang, Xitao

    2016-02-01

    The stress corrosion cracking (SCC) behavior of cast austenitic stainless steels of unaged and thermally aged at 400 °C for as long as 20,000 h were studied by using a slow strain rate testing (SSRT) system. Spinodal decomposition in ferrite during thermal aging leads to hardening in ferrite and embrittlement of the SSRT specimen. Plastic deformation and thermal aging degree have a great influence on the oxidation rate of the studied material in simulated PWR primary water environments. In the SCC regions of the aged SSRT specimen, the surface cracks, formed by the brittle fracture of ferrite phases, are the possible locations for SCC. In the non-SCC regions, brittle fracture of ferrite phases also occurs because of the effect of thermal aging embrittlement.

  20. Late Jurassic ocean anoxic event: evidence from voluminous sulphide deposition and preservation in the Panthalassa

    National Research Council Canada - National Science Library

    Nozaki, Tatsuo; Kato, Yasuhiro; Suzuki, Katsuhiko

    2013-01-01

    The historically productive copper-bearing Besshi-type sulphide deposits in the Japanese accretionary complex were formed as volcanogenic massive sulphide deposits on the deep-sea floor of the Panthalassa Ocean...

  1. 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.

  2. Recovery of Cu and Zn from Complex Sulphide Ore

    Science.gov (United States)

    Talapaneni, Trinath; Sarkar, S.; Yedla, N.; Reddy, P. L. N., Dr

    2015-02-01

    Complex Sulphide Ores are often found to be a close mutual association with each other and with the nonmetallic gangue. The beneficiation experiments showed that it would be very difficult to recover Cu and Zn from the lean complex Sulphide ores using traditional ore beneficiation methods. In the present work, leaching of complex sulfide ores in sulfuric acid was investigated by the Electro hydrometallurgy process. The lab-scale experiments were conducted to investigate the influences of pulp-density, electrolyte concentration, particle size, current density and time on recovery of Cu and Zn. The leach liquor obtained after electrolysis was subjected to Atomic Absorption Spectroscopy analysis for the recovery of minerals.

  3. Production of volatile Sulphides in Allium Porrum cell cultures

    Directory of Open Access Journals (Sweden)

    "Asghari Gh.R

    2002-09-01

    Full Text Available Production of volatile sulphides in cell cultures of Allium porrum is described. Allium porrum calluses were initiated from whole seedlings. The high growth rate of Allium porrum callus was achived in Murashige and Skoog media containing only 1 ppm 2, 4-Dichlorophenoxy acetic acid. The routine method of solvent extraction of volatile sulphides was used for Allium porrum and the concentrated extract was subjected to capillary GC and GC-MS. Dipropyl disulphide and 4-methyl thiazolethanol were identified in A. porrum aggregated suspension cells.

  4. Influences of Corrosive Sulfur on Copper Wires and Oil-Paper Insulation in Transformers

    OpenAIRE

    Jian Li; Zhiman He; Lianwei Bao; Lijun Yang

    2011-01-01

    Oil-impregnated paper is widely used in power transmission equipment as a reliable insulation. However, copper sulphide deposition on oil-paper insulation can lead to insulation failures in power transformers. This paper presents the influences of copper sulfur corrosion and copper sulphide deposition on copper wires and oil-paper insulation in power transformers. Thermal aging tests of paper-wrapped copper wires and bare copper wires in insulating oil were carried out at 130 °C and 150 °C in...

  5. Corrosion of copper in alkaline chloride environments

    Energy Technology Data Exchange (ETDEWEB)

    King, F. [Integrity Corrosion Consulting Ltd., Calgary (Canada)

    2002-08-01

    The available literature information on the corrosion and electrochemical behaviour of copper in alkaline environments has been reviewed. The purpose of the review was to assess the impact of an alkaline plume from cementitious material on the corrosion behaviour of a copper canister in an SKB-3 type repository. The effect of the evolution of the environmental conditions within the repository have been considered, including the effects of temperature, redox conditions, pore-water salinity and pH. If the pore-water pH increases prior to the establishment of anoxic conditions, the canister surface will passivate as the pore-water pH exceeds a value of {approx} pH 9. Passivation will result from the formation of a duplex Cu{sub 2}O/Cu(OH){sub 2} film. The corrosion potential will be determined by the equilibrium potential for the Cu{sub 2}O/Cu(OH){sub 2} couple under oxic conditions, or by the Cu/Cu{sub 2}O redox couple under anoxic conditions (in the absence of sulphide). Pitting corrosion is only likely to occur early in the evolution of the repository environment, whilst the canister is still relatively cool (<40 deg C), whilst there is still O{sub 2} available to support localised corrosion, and prior to the increase in pore-water pH and salinity. The subsequent increase in canister surface temperature, pore-water pH and salinity, and decrease in O{sub 2} will make pit initiation less likely, although the canister will remain passive provided the pore-water pH is maintained above pH 9. The higher the pore-water pH, the more strongly the canister is passivated and the less likely the surface is to undergo localised attack. If the pore-water salinity increases prior to the increase in pH, there could be a period of active canister corrosion before passivation occurs.Under these circumstances, the corrosion potential will be a true mixed potential, determine by the relative kinetics of Cu dissolution as CuCl{sub 2} - and of the reduction of O{sub 2}. The development

  6. Corrosion mechanism applicable to biodegradable magnesium implants

    Energy Technology Data Exchange (ETDEWEB)

    Atrens, Andrej, E-mail: Andrejs.Atrens@uq.edu.au [University of Queensland, Division of Materials, Brisbane, Qld 4072 (Australia); Liu Ming; Zainal Abidin, Nor Ishida [University of Queensland, Division of Materials, Brisbane, Qld 4072 (Australia)

    2011-12-15

    Much of our understanding of the Mg corrosion mechanism is based on research using aggressive chloride based solutions like 3% NaCl, which are appropriate for understand the corrosion for applications such as auto construction. The chloride ions tend to cause break down of the partly protective surface film on the Mg alloy surface. The corrosion rate increases with exposure time until steady state is reached, which may take several weeks. An overview is provided of the aspects which determine the corrosion of Mg alloys: (i) measurement details; (ii) impurity elements Fe, Ni, Cu and Co; (iii) second phases; (iv) surface films and surface condition and (v) stress corrosion cracking (SCC). This understanding is used to help understand Mg corrosion for Mg as a biodegradable implant for medical applications. Solutions that elucidate these applications tend to form surface films and the corrosion rate tends to decrease with immersion time.

  7. Synthesis of TOPO-capped Nanocrystals of Copper Sulphide from a ...

    African Journals Online (AJOL)

    Nanocrystals, copper(I) sulphide, TOPO, photoluminescence, TEM, SAED. 1. Introduction. Copper sulphide is a potentially cheap and less hazardous material than CdS, CdSe and PbS but has received scant atten- tion. The synthesis of copper sulphide has been achieved from aqueous sols,1 monolayers,2 bilayer lipid ...

  8. Corrosion and alteration of materials from the nuclear industry; La Corrosion et l'alteration des materiaux du nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Feron, D.; Guerin, Y.; Latge, C.; Limoge, Y.; Madic, C.; Santarini, G.; Seiler, J.M.; Vernaz, E.; Richet, C.

    2010-07-01

    The control of the corrosion phenomenon is of prime importance for the nuclear industry. The efficiency and the safety of facilities can be affected by this phenomenon. The nuclear industry has to face corrosion for a large variety of materials submitted to various environments. Metallic corrosion operates in the hot and aqueous environment of water reactors which represent the most common reactor type in the world. Progresses made in the control of the corrosion of the different components of these reactors allow to improve their safety. Corrosion is present in the facilities of the back-end of the fuel cycle as well (corrosion in acid environment in fuel reprocessing plants, corrosion of waste containers in disposal and storage facilities, etc). The future nuclear systems will widen even more the range of materials to be studied and the situations in which they will be placed (corrosion by liquid metals or by helium impurities). Very often, corrosion looks like a patchwork of particular cases in its description. The encountered corrosion problems and their study are presented in this book according to chapters representing the main sectors of the nuclear industry and classified with respect to their phenomenology. This monograph illustrates the researches in progress and presents some results of particular importance obtained recently. Content: 1 - Introduction: context, stakes and goals; definition of corrosion; a complex science; corrosion in the nuclear industry; 2 - corrosion in water reactors - phenomenology, mechanisms, remedies: A - uniform corrosion: mechanisms, uniform corrosion of fuel cladding, in-situ measurement of generalized corrosion rate by electrochemical methods, uniform corrosion of nickel alloys, characterization of the passive layer and growth mechanisms, the PACTOLE code - an integrating tool, influence of water chemistry on corrosion and contamination, radiolysis impact on uniform corrosion; B - stress corrosion: stress corrosion cracking

  9. Tolerance of benthic foraminifera (Protista : Sarcodina) to hydrogen sulphide

    NARCIS (Netherlands)

    Moodley, L.; Schaub, B.; Van der Zwaan, G.J.; Herman, P.M.J.

    1998-01-01

    Benthic foraminifera are dominant members of tb meiofauna, commonly occurring below the anoxic-oxic interface in marine sediments. The absence of oxygen in marine coastal sediments is often correlated with the formation of hydrogen sulphide. In this study the tolerance of benthic foraminifera (from

  10. Optical Properties of Lead Silver Sulphide Ternary Thin Films ...

    African Journals Online (AJOL)

    Lead Silver Sulphide (PbAgS) thin films on glass substrate have been deposited by chemical bath deposition technique with EDTA and TEA as complexing agents, while ammonium solution served as pH adjuster. The films were deposited at room temperature of 300K. The deposited films were characterized using UV ...

  11. Application of induced polarization method to delineate sulphide ore ...

    African Journals Online (AJOL)

    The occurrence of sulphide ore bodies in Osina area of Benue state has been reported earlier in the geology of Nigeria map, but the extent and abundance of the mineral was not known. In this work, we investigated the thickness and depth of the mineral deposit. Ground Induced Polarization (GIP) survey employing the ...

  12. Fungal-Transformation of Surrogate Sulphides and Carbonaceous ...

    African Journals Online (AJOL)

    Michael

    2017-12-02

    Dec 2, 2017 ... In the recovery of gold from refractory gold ores, pretreatment is required to decompose sulphides and liberate occluded gold before cyanidation, and to deactivate carbonaceous matter and prevent it from adsorbing dissolved gold. Until the past three decades, most commercial pretreatment processes had ...

  13. Fungal-Transformation of Surrogate Sulphides and Carbonaceous ...

    African Journals Online (AJOL)

    In the recovery of gold from refractory gold ores, pretreatment is required to decompose sulphides and liberate occluded gold before cyanidation, and to deactivate carbonaceous matter and prevent it from adsorbing dissolved gold. Until the past three decades, most commercial pretreatment processes had been by abiotic ...

  14. Cadmium sulphide thin film for application in gamma radiation ...

    African Journals Online (AJOL)

    Cadmium Sulphide (CdS) thin film was prepared using pyrolytic spraying technique and then irradiated at varied gamma dosage. The CdS thin film absorption before gamma irradiation was 0.6497. Absorbed doses were computed using standard equation established for an integrating dosimeter. The plot of absorbed dose ...

  15. High-temperature biotrickling filtration of hydrogen sulphide.

    Science.gov (United States)

    Datta, Indrani; Fulthorpe, Roberta R; Sharma, Shobha; Allen, D Grant

    2007-03-01

    Biofiltration of malodorous reduced sulphur compounds such as hydrogen sulphide has been confined to emissions that are at temperatures below 40 degrees C despite the fact that there are many industrial emissions (e.g. in the pulp and paper industry) at temperatures well above 40 degrees C. This paper describes our study on the successful treatment of hydrogen sulphide gas at temperatures of 40, 50, 60 and 70 degrees C using a microbial community obtained from a hot spring. Three biotrickling filter (BTF) systems were set up in parallel for a continuous run of 9 months to operate at three different temperatures, one of which was always at 40 degrees C as a mesophilic control and the other two were for exploring high-temperature operation up to 70 degrees C. The continuous experiment and a series of batch experiments in glass bottles (250 ml) showed that addition of glucose and monosodium glutamate enhanced thermophilic biofiltration of hydrogen sulphide gas and a removal rate of 40 g m(-3) h(-1) was achieved at 70 degrees C. We suggest that the glucose is acting as a carbon source for the existing microbial community in the BTFs, whereas glutamate is acting as a compatible solute. The use of such organic compounds to enhance biodegradation of hydrogen sulphide, particularly at high temperatures, has not been demonstrated to our knowledge and, hence, has opened up a range of possibilities for applying biofiltration to hot gas effluent.

  16. Preparation of copper sulphide clusters in organic–inorganic ...

    Indian Academy of Sciences (India)

    Unknown

    Copper sulphide clusters; Langmuir–Blodgett films; organic–inorganic composites; amphiphilic Schiff ... have reported that gold nanoparticles modified with single stranded DNA oligonucleotides can be ... been known to form stable monolayers at the air/water interface and can complex with a variety of metal ions 20,21.

  17. Pengaruh Penggunaan Konsentrasi Amonium Sulphide pada Pewarnaan Kerajinan Logam Perak

    Directory of Open Access Journals (Sweden)

    Dwi Suheryanto

    2016-04-01

    Full Text Available Proses pewarnaan kerajinan logam perak dengan amonium sulphide dapat memberikan hasil yang memberi kesan dekoratif dan menarik, karena proses tersebut merupakan hasil reaksi antara zat tersebut dengan logam perak sebagai benda kerja.Proses pewarnaan logam perak menggunakan variasi konsentrasi ammonium sulphide 100 cc, 125 cc, dan 125 cc per 850 cc air dengan variasi waktu 5 menit; 7,5 menit; dan 10 menit. Logam perak yang digunakan perak 925 ukuran 2 x 3 cm berat 25 gram, dan teknik yang digunakan dengan cara merendam benda kerja pada larutan ammonium sulphide pada suhu 50o C.Hasil pengujian terhadap ketahanan atau perubahan warna dan ketuaan warna menunjukkan bahwa proses pewarnaan logam perak 925 pada temperatur 50o C, dengan konsentrasi 125 cc dengan waktu 7,5 menit memberikan hasil ketuaan dan ketahanan warna yang baik dengan nilai rata – rata 1 dan menimbulkan warna hitam keabu – abuan dengan nilai rata – rata 1 – 2. Kata kunci : ammonium sulphide, perak, pewarnaan

  18. Page 1 THE OXIDATION OF HYDRO GEN SULPHIDE BY ...

    Indian Academy of Sciences (India)

    to prevent the hydrolysis of iodine monochloride, the sulphur was quanti- tatively oxidised to Sulphate. Our preliminary experiments showed that as in the case of chloramine-T the products formed by the oxidation of hydrogen sulphide by potassium iodate Were Sulphur and sulphate, depending upon the pH of the system.

  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). Copyright © 2013 Wiley Periodicals, Inc.

  20. Effect of CT Specimen Thickness on the Mechanical Characteristics at the Crack Tip of Stress Corrosion Cracking in Ni-based Alloys

    Science.gov (United States)

    Yinghao, Cui; He, Xue; Lingyan, Zhao

    2017-12-01

    It’s important to obtain accurate stress corrosion crack(SCC) growth rate for quantitative life prediction of components in nuclear power plants. However, the engineering practice shows that the crack tip constraint effect has a great influence on the mechanical properties and crack growth rate of SCC at crack tip. To study the influence of the specimen thickness on the crack tip mechanical properties of SCC, the stress, strain and C integral at creep crack tip are analyzed under different specimens thickness. Results show that the cracked specimen is less likely to crack due to effect of crack tip constraint. When the thickness ratio B/W is larger than 0.1, the crack tip constraint is almost ineffective. Value of C integral is the largest when B/W is 0.25. Then specimen thickness has little effect on the value of C integral. The effect of specimen thickness on the value of C integral is less significant at higher thickness ratio.

  1. Uncommon corrosion phenomena of archaeological bronze alloys

    Science.gov (United States)

    Ingo, G. M.; de Caro, T.; Riccucci, C.; Khosroff, S.

    2006-06-01

    In the framework of the EFESTUS project (funded by the European Commission, contract No. ICA3-CT-2002-10030) the corrosion products of a large number of archaeological bronze artefacts are investigated by means of the combined use of scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and optical microscopy (OM) and tentative correlation of their nature with the chemical composition of the artefacts and the burial context is proposed. The results provide good insight into the corrosion layers and evidence in some bronze Roman coins and artefacts; the occurrence of uncommon corrosion phenomena that give rise to the formation of a yellowish-green complex chlorine-phosphate of lead (pyromorphite, (PbCl)Pb4(PO4)3) and of a gold-like thick layer of an iron and copper sulphide (chalcopyrite, CuFeS2). The micro-chemical and micro-structural results show that the coins were buried in a soil enriched in phosphorus for the accidental presence of a large amount of decomposing fragments of bones or in an anaerobic and humus rich soil where the chalcopyrite layer has been produced via the interaction between the iron of the soil, the copper of the coin and the sulphur produced by the decomposition of organic matter in an almost oxygen free environment. Finally, some unusual periodic corrosion phenomena occurring in high tin bronze mirrors found at Zama (Tunisia) are described.

  2. Thermally activated low temperature creep and primary water stress corrosion cracking of NiCrFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hall, M.M. Jr.

    1993-10-01

    A phenomenological SCC-CGR model is developed based on an apriori assumption that the SCC-CGR is controlled by low temperature creep (LTC). This mode of low temperature time dependent deformation occurs at stress levels above the athermal flow stress by a dislocation glide mechanism that is thermally activated and may be environmentally assisted. The SCC-CGR model equations developed contain thermal activation parameters descriptive of the dislocation creep mechanism. Thermal activation parameters are obtained by fitting the CGR model to SCC-CGR data obtained on Alloy 600 and Alloy X-750. These SCC-CGR activation parameters are compared to LTC activation parameters obtained from stress relaxation tests. When the high concentration of hydrogen at the tip of an SCC crack is considered, the SCC-CGR activation energies and rate sensitivities are shown to be quantitatively consistent with hydrogen reducing the activation energy and increasing the strain rate sensitivity in LTC stress relaxation tests. Stress dependence of SCC-CGR activation energy consistent with that found for the LTC activation energy. Comparisons between temperature dependence of the SCC-CGR stress sensitivity and LTC stress sensitivity provide a basis for speculation on effects of hydrogen and solute carbon on SCC crack growth rates.

  3. Evaluation of corrosion products formed by sulfidation as inhibitors of the naphthenic corrosion of AISI-316 steel

    Science.gov (United States)

    Sanabria-Cala, J. A.; Montañez, N. D.; Laverde Cataño, D.; Y Peña Ballesteros, D.; Mejía, C. A.

    2017-12-01

    Naphthenic acids present in oil from most regions worldwide currently stand as the main responsible for the naphthenic corrosion problems, affecting the oil-refining industry. The phenomenon of sulfidation, accompanying corrosion processes brought about by naphthenic acids in high-temperature refining plant applications, takes place when the combination of sulfidic acid (H2S) with Fe forms layers of iron sulphide (FeS) on the material surface, layers with the potential to protect the material from attack by other corrosive species like naphthenic acids. This work assessed corrosion products formed by sulfidation as inhibitors of naphthenic corrosion rate in AISI-316 steel exposed to processing conditions of simulated crude oil in a dynamic autoclave. Calculation of the sulfidation and naphthenic corrosion rates were determined by gravimetry. The surfaces of the AISI-316 gravimetric coupons exposed to acid systems; were characterized morphologically by X-Ray Diffraction (XRD) and X-ray Fluorescence by Energy Dispersive Spectroscopy (EDS) combined with Scanning Electron Microscopy (SEM). One of the results obtained was the determination of an inhibiting effect of corrosion products at 250 and 300°C, where lower corrosion rate levels were detected. For the temperature of 350°C, naphthenic corrosion rates increased due to deposition of naphthenic acids on the areas where corrosion products formed by sulfidation have lower homogeneity and stability on the surface, thus accelerating the destruction of AISI-316 steel. The above provides an initial contribution to oil industry in search of new alternatives to corrosion control by the attack of naphthenic acids, from the formation of FeS layers on exposed materials in the processing of heavy crude oils with high sulphur content.

  4. 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.)

  5. Characterization of hydrogen absorption during stress corrosion cracking of a 600 alloy in the primary environment of pressurized water reactors (PWR); Caracterisation de l'absorption de l'hydrogene lors de la corrosion sous contrainte (CSC) de l'alliage 600 en milieu primaire des reacteurs a eau pressurisee (REP)

    Energy Technology Data Exchange (ETDEWEB)

    Jambon, F.; Marchetti, L. [CEA Saclay, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Aqueuse, 91 - Gif-sur-Yvette (France); Chene, J. [CEA Saclay, UMR 8587 - Equipe Hydrogene / Materiaux de structure, CEA, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Aqueuse, 91 - Gif-sur-Yvette (France); Jomard, F. [GEMaC, CNRS Meudon, 92 - Meudon (France)

    2010-03-15

    The objective of this study is the understanding of hydrogen transport and absorption phenomena in nickel base materials in the primary type environment of pressurized water reactors (PWR). First, the authors report a literature survey on the role of hydrogen in alloy 600 stress corrosion cracking. This survey enabled experiments to be chosen and applied, the results of which are then discussed. Exposed samples are examined by secondary ion mass spectroscopy

  6. 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]).

  7. Characterization of Stress Corrosion Cracking at the Welded Region of High Strength Steel using Acoustic Emission Method

    Energy Technology Data Exchange (ETDEWEB)

    Na, Eui Gyun [Kunsan University, Kunsan (Korea, Republic of); Kim, Hoon [Yosu National University, Yeosu (Korea, Republic of)

    2003-06-15

    This study is to evaluate the characteristics of SCC at the welded region of high strength steel using acoustic emission(AE) method. Specimens were loaded by a slow strain rate method in synthetic seawater and the damage process was monitored simultaneously by AE method. Corrosive environment was controlled using the potentiostat, in which -0.8V and -1.1V were applied to the specimens. In the case of one-pass weldment subjected to -0.8V, much more AE counts were detected compared with the PWHT specimen. It was verified through the cumulative counts that coalescence of micro cracks and cracks for the one pass weldment with -0.8V were mostly detected. In case of the one pass weldment subjected to -1.1V, time to failure became shorter and AE counts were produced considerably as compared with that of the two pass weldment. It was shown that AE counts and range of AE amplitude have close relations with the number and size as well as width of the cracks which were formed during the SCC

  8. 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.

  9. 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.

  10. Corrosion Behavior of Carbon Steel in Synthetically Produced Oil Field Seawater

    Directory of Open Access Journals (Sweden)

    Subir Paul

    2014-01-01

    Full Text Available The life of offshore steel structure in the oil production units is decided by the huge corrosive degradation due to SO42-, S2−, and Cl−, which normally present in the oil field seawater. Variation in pH and temperature further adds to the rate of degradation on steel. Corrosion behavior of mild steel is investigated through polarization, EIS, XRD, and optical and SEM microscopy. The effect of all 3 species is huge material degradation with FeSx and FeCl3 and their complex as corrosion products. EIS data match the model of Randle circuit with Warburg resistance. Addition of more corrosion species decreases impedance and increases capacitance values of the Randle circuit at the interface. The attack is found to be at the grain boundary as well as grain body with very prominent sulphide corrosion crack.

  11. 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...

  12. 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

  13. DWPF corrosion study

    Energy Technology Data Exchange (ETDEWEB)

    Selby, C.L.

    1986-12-17

    Corrosion of candidate alloys for the DWPF SRAT, SME, and melter was tested in the large (1/3 scale) SRAT/SME, the 200th scale SRAT/SME, and the LSFM. Flat or twisted coupons with or without a weld bead and U-bend specimens (specimens bent into a ''U'' shape and bolted together at the ends to stress the bend area) were installed on racks that ensured electrical isolation to avoid galvanic effects. Teflon/reg sign/ washers isolated the low temperature exposure racks and ceramic washers isolated the high temperature exposure racks. Serrated washers simulated crevices, but crevice corrosion did not result. 9 refs., 9 tabs.

  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. Effect of High Cl- Environment on Stress Corrosion Cracking Behavior of M152 and 17-4PH High-strength Steels

    Directory of Open Access Journals (Sweden)

    WU Wei

    2018-02-01

    Full Text Available The stress corrosion cracking (SCC behavior and mechanism of M152 and 17-4PH high-strength steels in high Cl- environment were studied through neutral salt spray test and slow strain rate tensile (SSRT test. The result shows that M152 and 17-4PH steels exhibit a certain sensitivity to SCC in Cl- environment, elongations of them both decrease with the increasing time of early neutral salt spray test, and the SCC sensitivity gradually increases. Comparing the fracture morphology with lateral crack through SEM, it can be found that the fracture mechanism of M152 and 17-4PH high-strength steels converts ductile fracture to brittle fracture as the extension of neutral salt spray test time. The synergistic effect of anodic dissolution (AD and hydrogen embrittlement (HE result in the occurrence of SCC in high Cl- environment, and Cl- can promote the AD process. Due to the obvious effect of HE, 17-4PH steel has higher SCC sensitivity than M152 steel with the same time of early neutral salt spray test. 17-4PH high-strength steel is more prone to SCC than M152 in high Cl- environment.

  18. Stress corrosion cracking in Björk-Shiley convexo-concave prosthetic heart valves due to random in vivo electrochemical pulsing.

    Science.gov (United States)

    Xiao, K; Appleby, A J

    1996-08-01

    Welded downstream struts of Björk-Shiley Convexo-Concave heart valves show failure in vivo, but not in in vitro testing. A pyrolytic carbon pivoting disk occluder closes against a Haynes 25 alloy ring, which is electrochemically machined from solid with the upstream retaining struts. The weld area is de-alloyed, with residual porosity and carbide inclusions. The valve becomes a short-circuited electrochemical cell when fully open or closed. It is an aggressive chloride electrolyte, whose high pulsed flow (2 m/s) ensures that supply of oxygen-rich cathode reactant is not mass-transport-limited. During the flight of the occluder, the cell is randomly at open circuit. A random current pulse is applied to the metal parts on circuit closure. Failure is not from simple mechanical fatigue, but from stress-corrosion-cracking and erosion of the less noble weld area caused by these pulses. All welded valves of this type may be susceptible to ultimate in vivo failure.

  19. Effects of temperature on stress corrosion cracking behavior of stainless steel and outer oxide distribution in cracks due to exposure to high-temperature water containing hydrogen peroxide

    Science.gov (United States)

    Nakano, Junichi; Sato, Tomonori; Kato, Chiaki; Yamamoto, Masahiro; Tsukada, Takashi; Kaji, Yoshiyuki

    2014-01-01

    Cracking growth tests were conducted in high-temperature water containing hydrogen peroxide (H2O2) at 561-423 K to evaluate the effects of H2O2 on stress corrosion cracking (SCC) of stainless steel (SS) at temperature lower than the boiling water reactor (BWR) operating temperature. Small compact tension (CT) specimens were prepared from thermally sensitized type 304 SS. Despite the observation of only a small portion intergranular SCC (IGSCC) near the side groove of the CT specimen at 561 K in high-temperature water containing 100 ppb H2O2, the IGSCC area expanded to the central region of the CT specimens at 423 and 453 K. Effects of H2O2 on SCC appeared intensely at temperature lower than the BWR operating temperature because of a reduction in the thermal decomposition of H2O2. To estimate the environment in the cracks, outer oxide distribution on the fracture surface and the fatigue pre-crack were examined by laser Raman spectroscopy and thermal equilibrium calculation was performed.

  20. Morphology of stress corrosion cracking due to exposure to high-temperature water containing hydrogen peroxide in stainless steel specimens with different crevice lengths

    Science.gov (United States)

    Nakano, Junichi; Sato, Tomonori; Kato, Chiaki; Yamamoto, Masahiro; Tsukada, Takashi; Kaji, Yoshiyuki

    2013-10-01

    Crack growth tests were performed in high-temperature water containing hydrogen peroxide (H2O2) to evaluate the relationships between the crevice structure and H2O2 on stress corrosion cracking (SCC) growth morphology of stainless steel (SS). Small compact tension (CT) specimens were prepared from thermally sensitized type 304 SS. 20-300 ppb H2O2 was injected into the high-temperature water at 561 K. Intergranular SCC (IGSCC) and transgranular SCC were observed near the side grooves and the central region of the original CT specimens, respectively. Chevron notches were removed from the CT specimens after fatigue pre-crack introduction. Owing to pre-crack shortening, the IGSCC area expanded to the central region of the CT specimens and increased with H2O2 concentration. The effects of H2O2 on SCC appeared intensely near the surfaces exposed to high levels of H2O2. Microanalysis and distribution examination of oxide layers were performed and the percentage of H2O2 remaining in the crack was calculated.

  1. The Stress Corrosion Resistance and the Cryogenic Temperature Mechanical Behavior of 18-3 Mn (Nitronic 33) Stainless Steel Parent and Welded Material

    Science.gov (United States)

    Montano, J. W.

    1976-01-01

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion results of 18-3 Mn (Nitronic 33)stainless steel, longitudinal and transverse, as received and as welded (TIG) material specimens manufactured from 0.063 inch thick sheet material, were described. The tensile test results indicate an increase in ultimate tensile and yield strengths with decreasing temperature. The elongation remained fairly constant to -200 F, but below that temperature the elongation decreased to less than 6.0% at liquid hydrogen temperature. The notched tensile strength (NTS) for the parent metal increased with decreasing temperature to liquid nitrogen temperature. Below -320 F the NTS decreased rapidly. The notched/unnotched (N/U) tensile ratio of the parent material specimens remained above 0.9 from ambient to -200 F, and decreased to approximately 0.65 and 0.62, respectively, for the longitudinal and transverse directions at liquid hydrogen temperature. After 180 days of testing, only those specimens exposed to the salt spray indicated pitting and some degradation of mechanical properties.

  2. Characterization of stress corrosion cracks in Ni-based weld alloys 52, 52M and 152 grown in high-temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yi [Nuclear Engineering Program, The Ohio State University, Columbus, OH 43210 (United States); Wu, Yaqiao; Burns, Jatuporn [Department of Materials Science and Engineering, Boise State University, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83401 (United States); Zhang, Jinsuo, E-mail: zhang.3558@osu.edu [Nuclear Engineering Program, The Ohio State University, Columbus, OH 43210 (United States)

    2016-02-15

    Ni-based weld alloys 52, 52M and 152 are extensively used in repair and mitigation of primary water stress corrosion cracking (SCC) in nuclear power plants. In the present study, a series of microstructure and microchemistry at the SCC tips of these alloys were examined with scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), scanning transmission electron microscopy (STEM) and energy filtered transmission electron microscopy (EFTEM). The specimens have similar chemical compositions and testing conditions. Intergranular (IG) and transgranular (TG) SCC was observed in all of them. The cracks were filled with nickel-oxides and partial precipitations of chrome carbides (CrCs), niobium carbides (NbCs), titanium nitrides (TiNs) and silicon carbides (SiCs), while iron (Fe) was largely dissolved into the solution. However, the crack densities, lengths and distributions were different for all three specimens. - Highlights: • Microstructure and microchemistry at the SCC tips of Ni-based weld alloys 52, 52M and 152 were examined. • The crack densities, lengths and distributions were found to be different for different alloys. • IGSCC and TGSCC were observed on alloy 52, only TGSCC was observed on alloy 52M and 152. • The cracks were filled by Ni-oxides and precipitated CrCs, NbCs, TiNs and SiCs.

  3. Hydrogen sulphide and phosphine interactions with human skin in vitro.

    Science.gov (United States)

    Gaskin, Sharyn; Heath, Linda; Pisaniello, Dino; Evans, Richard; Edwards, John W; Logan, Michael; Baxter, Christina

    2017-04-01

    Accidental or intentional releases of toxic gases can have significant public health consequences and emergency resource demands. Management of exposed individuals during hazardous material incidents should be risk and evidence based, but there are knowledge gaps in relation to dermal absorption of gases and management advice for potentially exposed individuals. Using a modified Organization for Economic Co-operation and Development (OECD) in vitro toxicology protocol with human donor skin, this article reports on two common and odorous chemicals, hydrogen sulphide and phosphine. Results show that undamaged human skin provides a good barrier to hydrogen sulphide (up to 800 ppm) and phosphine (up to 1000 ppm) penetration for up to 30 min exposures, with little variability in the presence of clothing or in elevated temperature and humidity conditions. A practical guideline template for skin decontamination has been developed, and implications of the research for first responders are outlined.

  4. 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.

  5. Optical Properties of Silver Aluminium Sulphide Ternary Thin Films ...

    African Journals Online (AJOL)

    Ternary thin films of Silver Aluminium Sulphide (AgAlS2) have been prepared by chemical bath deposition techniques. Aqueous solution of 41.5 mls containing AgNO3, Al2(SO4)3, thiourea and EDTA was used, where AgNO3, Al2(SO4)3, thiourea were the source of Ag+, Al+ and S- respectively and EDTA was used as a ...

  6. Sulphidation of the oceanic lithosphere: an experimental approach

    Science.gov (United States)

    Los, Catharina; Hansen, Christian; Bach, Wolfgang

    2017-04-01

    Newly formed oceanic lithosphere close to spreading centers can be influenced by fluids that feed hydrothermal vents. These fluids often carry high amounts of dissolved gases such as H2S, which can trigger precipitation of sulphide minerals in the interacting rock during percolation. This process occurs equally in exposed mantle rock, serpentinised mantle rock, troctolite or gabbro and basalt, the lithology depending on the spreading rate at the ridge where hydrothermal activity is present. These later-stage fluid-rock interactions can develop different types of sulphide mineralization in the lithosphere. In order to better understand these sulphidation reactions, we have conducted several batch experiments that placed different oceanic lithologies in contact with an H2S saturated, iron-free solution. The mixture was heated to 250°C at 400 bars and kept under these conditions for 2-8 weeks. In situ fluid and gas sampling was used to monitor reaction progress. REM-analysis of the solid products has shown the growth of euhedral pyrite and magnetite crystals as well as dissolution textures in feldspar and olivine. The presence of pyrite (gabbro experiment) and magnetite (troctolite and serpentinite) is in agreement with the measured H2- and H2S-content in the analysed fluids. These Fe-bearing minerals grew although no iron was added to the fluid, showing the replacive nature of the reaction. Geochemical modeling can be used to extend the application of these observations to different PT-conditions. Using this technique, we can start tackling the problem of replacive sulphide formation within hydrothermal discharge zones in oceanic basement of variable composition.

  7. Adsorption of hydrogen sulphide on Metal-Organic Frameworks

    NARCIS (Netherlands)

    Gutiérrez-Sevillano, J.J.; Martin-Calvo, A.; Dubbeldam, D.; Calero, S.; Hamad, S.

    2013-01-01

    Three new sets of interatomic potentials to model hydrogen sulphide (H2S) have been fitted. One of them is a 3-sites potential (which we named 3S) and the other two are 5-sites potentials (which we named 5S and 5Sd). The molecular dipole of the 3S and 5S potentials is 1.43 D, which is the value

  8. The relative stress-corrosion-cracking susceptibility of candidate aluminum-lithium alloys for aerospace structural applications

    Science.gov (United States)

    Pizzo, P. P.

    1980-01-01

    The microstructure and tensile properties of two powder metallurgy processed aluminum-lithium alloys were determined. Strength properties of 480 MPa yield and 550 MPa ultimate tensile strength with 5% strain to fracture were attained. Very little reduction in area was observed and fracture characteristics were brittle. The magnesium bearing alloy exhibited the highest strength and ductility, but fracture was intergranular. Recrystallization and grain growth, as well as coarse grain boundary precipitation, occurred in Alloy 2. The fracture morphology of the two alloys differed. Alloy 1 fractured along a plane of maximum shear stress, while Alloy 2 fractured along a plane of maximum tensile stress. It is found that a fixed orientation relationship exists between the shear fracture plane and the rolling direction which suggests that the PM alloys are strongly textured.

  9. 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)

  10. 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

  11. Aircraft Corrosion

    Science.gov (United States)

    1981-08-01

    au traitement. micaniqus qui provoque une compression de surface - h1l’spplication i1’une double protection comportant oxydation snodique et...primaire anti-corrosion nitrosynthdtique pigmontie au chromate do zinc - une couche do peinture de finition nitrosynthdtique risistant aux huiles ...condition: - Touch-up of concerned fastener holes with chemical oxydation ; - Wet assembly of fasteners; - Application of a strontium chromate primer and

  12. 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...

  13. Sulphide Production and Corrosion in Seawaters During Exposure to FAME Diesel

    Science.gov (United States)

    2012-05-12

    Quantification of sulfate-reducing bacteria in industrial wastewater, by real-time polymerase chain reaction (PCR) using dsrA and apsA genes. Microb Ecol...Lai QL, Dong CM, Shao ZZ. 2008. Biodiversity of polycyclic aromatic hydrocarbon-degrading bacteria from deep sea sediments of the Middle Atlantic

  14. Coupled Transport/Reaction Modelling of Copper Canister Corrosion Aided by Microbial Processes

    Energy Technology Data Exchange (ETDEWEB)

    Jinsong Liu [Royal Institute of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    2006-04-15

    Copper canister corrosion is an important issue in the concept of a nuclear fuel repository. Previous studies indicate that the oxygen-free copper canister could hold its integrity for more than 100,000 years in the repository environment. Microbial processes may reduce sulphate to sulphide and considerably increase the amount of sulphides available for corrosion. In this paper, a coupled transport/reaction model is developed to account for the transport of chemical species produced by microbial processes. The corroding agents like sulphide would come not only from the groundwater flowing in a fracture that intersects the canister, but also from the reduction of sulphate near the canister. The reaction of sulphate-reducing bacteria and the transport of sulphide in the bentonite buffer are included in the model. The depth of copper canister corrosion is calculated by the model. With representative 'central values' of the concentrations of sulphate and methane at repository depth at different sites in Fennoscandian Shield the corrosion depth predicted by the model is a few millimetres during 10{sup 5} years. As the concentrations of sulphate and methane are extremely site-specific and future climate changes may significantly influence the groundwater compositions at potential repository sites, sensitivity analyses have been conducted. With a broad perspective of the measured concentrations at different sites in Sweden and in Finland, and some possible mechanisms (like the glacial meltwater intrusion and interglacial seawater intrusion) that may introduce more sulphate into the groundwater at intermediate depths during future climate changes, higher concentrations of either/both sulphate and methane than what is used as the representative 'central' values would be possible. In worst cases. locally, half of the canister thickness could possibly be corroded within 10{sup 5} years.

  15. Knowledge on possibilities of applying mineral biotechnology to treatment of Slovak sulphide ores

    Directory of Open Access Journals (Sweden)

    Štyriaková Iveta

    1997-09-01

    Full Text Available The summary of results from research aimed at possibilities to use biotechnological procedures for treatment of Slovak sulphide ores is presented in this study. The object of the research is an extraction of valuable metals, undesirable admixtures and degradation of crystallic lattice of sulphides for subsequent chemical leaching processing of precious metals. Further, the results of experiments on existence of biogenic processes in situ on waste dumps from exploitation containing residual sulphides are presented.

  16. Influence of iron valency on the magnetic susceptibility of a microbially produced iron sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Marius, M S; James, P A B; Bahaj, A S; Smallman, D J [University of Southampton, School of Civil Engineering and the Environment, Southampton, SO17 1BJ (United Kingdom)

    2005-01-01

    Microbial iron sulphide is well known as an adsorbent for the treatment of metallic ion polluted wastewater. Under certain culture conditions a highly magnetic iron sulphide can be produced which would enable a low cost biomagnetic separation process to be developed. This paper illustrates that by raising the ferrous content of a ferrous - ferric sulphate rich medium the magnetic susceptibility of the iron sulphide produced is increased.

  17. Influence of iron valency on the magnetic susceptibility of a microbially produced iron sulphide.

    Science.gov (United States)

    Marius, M. S.; James, P. A. B.; Bahaj, A. S.; Smallman, D. J.

    2005-01-01

    Microbial iron sulphide is well known as an adsorbent for the treatment of metallic ion polluted wastewater. Under certain culture conditions a highly magnetic iron sulphide can be produced which would enable a low cost biomagnetic separation process to be developed. This paper illustrates that by raising the ferrous content of a ferrous - ferric sulphate rich medium the magnetic susceptibility of the iron sulphide produced is increased.

  18. 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.

  19. 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

  20. 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.

  1. Corrosion of stainless steels in simulated diesel exhaust environment with urea

    Energy Technology Data Exchange (ETDEWEB)

    Nockert, J.; Nyborg, L.; Norell, M. [Department of Materials and Manufacturing Technology, Chalmers University of Technology, 41296 Goeteborg (Sweden)

    2012-05-15

    Laboratory exposures have been performed simulating a selective catalytic reduction (SCR) system with urea injection for NO{sub x} reduction in diesel exhaust after-treatment. The corrosion behaviour of three ferritic and one austenitic stainless steel was examined using X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Continuous exposure to condensate did not cause any corrosion. Results show that cyclic interaction between high temperature and condensation aggravates the corrosion compared to isothermal exposure at 450 C. All ferritic alloys exhibited more or less the same behaviour, while the austenitic steel performed better. In fact, the presence of urea decreased the corrosion compared to the environment without urea. The cyclic samples exposed with urea displayed iron sulphate on the surface. The sulphate appeared to decrease the oxide thickness. A sulphur enrichment in the form of sulphide also occurred in the inner chromium-rich oxides of all cyclically exposed samples, both with and without urea. Thus, sulphidation is presumed to be involved in the corrosion process. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Evaluation and control of environmental corrosion for aluminum and steel alloys

    Science.gov (United States)

    Franklin, D. B.

    1977-01-01

    Corrosion protection systems for aerospace application and the effects of surface treatments and methods of controlling stress corrosion are evaluated. Chromate pigmented systems were found to be most effective for aluminum alloys; zinc-rich coatings gave the greatest protection to steel alloys. Various steel and aluminum alloys are rated for stress corrosion resistance.

  3. 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

  4. Prediction and optimisation of Pb/Zn/Fe sulphide scales in gas production fields

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, Sarah; Orski, Karine; Menezes, Carlos; Heath, Steve; MacPherson, Calum; Simpson, Caroline; Graham, Gordon

    2006-03-15

    Lead, zinc and iron sulphide scales are known to be a particular issue with gas production fields, particularly those producing from HP/HT reservoirs. However the prediction of sulphide scale and the methodologies available for their laboratory assessment are not as well developed as those for the more conventional sulphate and carbonate scales. This work examines a particular sulphide scaling regime from a North Sea high temperature gas condensate production field containing only 0.8ppm of sulphide ions. Sulphide scales were identified in the production system which was shown to be a mixture of lead and zinc sulphide, primarily lead sulphide. This formed as a result of cooling during production resulting in the over saturation of these minerals. This paper describes scale prediction and modified laboratory test protocols used to re-create the scales formed in the field prior to chemical performance testing. From the brine composition, scale prediction identified that the major scales that could be formed were calcium carbonate, iron carbonate, iron sulphide, lead sulphide and zinc sulphide. In addition, modification of the brine compositions led to prediction of primarily one scale or the other. Given the predicted over saturation of various minerals, preliminary laboratory tests were therefore conducted in order to ensure that the scale formed under laboratory conditions was representative of the field scale. Laboratory protocols were therefore developed to ensure that the scales formed in fully anaerobic dynamic performance tests and static performance tests were similar to those encountered in the field. The paper compares results from field analysis, scale predictions and laboratory scale formation tests using newly developed test protocols and shows differences between prediction and laboratory data. The paper therefore demonstrates the importance of ensuring that the correct scale is formed under laboratory test conditions and also indicates some potential

  5. Modeling of primary water stress corrosion cracking at control rod drive mechanism nozzles of pressurized water reactors; Modelagem da fratura por corrosao sob tensao nos bocais do mecanismo de acionamento das barras de controle de reator de agua pressurizada

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Omar Fernandes

    2006-07-01

    One of the main failure mechanisms that cause risks to pressurized water reactors is the primary water stress corrosion cracking (PWSCC) occurring in alloys. It can occurs, besides another places, at the control reactor displacement mechanism nozzles. It is caused by the joint effect of tensile stress, temperature, susceptible metallurgical microstructure and environmental conditions of the primary water. These cracks can cause accidents that reduce nuclear safety by blocking the rod's displacement and may cause leakage of primary water, reducing the reactor's life. In this work it is proposed a study of the existing models and a modeling proposal to primary water stress corrosion cracking in these nozzles in a nickel based Alloy 600. It is been superposed electrochemical and fracture mechanics models, and validated using experimental and literature data. The experimental data were obtained at CDTN-Brazilian Nuclear Technology Development Center, in a recent installed slow strain rate testing equipment. In the literature it is found a diagram that indicates a thermodynamic condition for the occurrence of some PWSCC sub modes in Alloy 600: it was used potential x pH diagrams (Pourbaix diagrams), for Alloy 600 in high temperature primary water (300 deg C till 350 deg C). Over it, were located the PWSCC sub modes, using experimental data. It was added a third parameter called 'stress corrosion strength fraction'. However, it is possible to superpose to this diagram, other parameters expressing PWSCC initiation or growth kinetics from other models. Here is the proposition of the original contribution of this work: from an original experimental condition of potential versus pH, it was superposed, an empiric-comparative, a semi-empiric-probabilistic, an initiation time, and a strain rate damage models, to quantify respectively the PWSCC susceptibility, the failure time, and in the two lasts, the initiation time of stress corrosion cracking. It was

  6. Influence of superplastic deformation on the corrosion resistance of aluminum alloys with microcrystalline structure

    Energy Technology Data Exchange (ETDEWEB)

    Rabinovich, M.Kh.; Trifonov, V.G. [Inst. for Metals Superplasticity Problems, Ufa (Russian Federation)

    1997-12-31

    It was established that superplastic deformation of aluminum alloys with microcrystalline structure reduces their corrosion resistance. However, the use of superplastic deformation compared to hot deformation of coarsecrystalline alloys, permits to increase the resistance of aluminum alloys to intercrystalline corrosion and to stress-corrosion cracking. The analysis of the electrochemical nature of corrosion made it possible to establish the cause of the discovered effect of superplastic deformation on corrosion resistance. (orig.) 15 refs.

  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. Corrosion of the copper canister in the repository environment

    Energy Technology Data Exchange (ETDEWEB)

    Hermansson, H.P.; Eriksson, Sture [Studsvik Material AB, Nykoeping (Sweden)

    1999-12-01

    The present report accounts for studies on copper corrosion performed at Studsvik Material AB during 1997-1999 on commission by SKI. The work has been focused on localised corrosion and electrochemistry of copper in the repository environment. The current theory of localised copper corrosion is not consistent with recent practical experiences. It is therefore desired to complete and develop the theory based on knowledge about the repository environment and evaluations of previous as well as recent experimental and field results. The work has therefore comprised a thorough compilation and up-date of literature on copper corrosion and on the repository environment. A selection of a 'working environment', defining the chemical parameters and their ranges of variation has been made and is used as a fundament for the experimental part of the work. Experiments have then been performed on the long-range electrochemical behaviour of copper in selected environments simulating the repository. Another part of the work has been to further develop knowledge about the thermodynamic limits for corrosion in the repository environment. Some of the thermodynamic work is integrated here. Especially thermodynamics for the system Cu-Cl-H-O up to 150 deg C and high chloride concentrations are outlined. However, there is also a rough overview of the whole system Cu-Fe-Cl-S-C-H-O as a fundament for the discussion. Data are normally accounted as Pourbaix diagrams. Some of the conclusions are that general corrosion on copper will probably not be of significant importance in the repository as far as transportation rates are low. However, if such rates were high, general corrosion could be disastrous, as there is no passivation of copper in the highly saline environment. The claim on knowledge of different kinds of localised corrosion and pitting is high, as pitting damages can shorten the lifetime of a canister dramatically. Normal pitting can happen in oxidising environment, but

  9. Allyl sulphides in olefin metathesis: catalyst considerations and traceless promotion of ring-closing metathesis.

    Science.gov (United States)

    Edwards, Grant A; Culp, Phillip A; Chalker, Justin M

    2015-01-11

    Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions.

  10. Improved sulphate removal rates at increased sulphide concentration in the sulphidogenic bioreactor

    CSIR Research Space (South Africa)

    Greben, HA

    2005-07-01

    Full Text Available The product of the biological sulphate reduction is sulphide. High concentrations of molecular H2S(g) can be inhibitory for microbial activity, especially at a reactor pH of 6 to 7. This paper focuses on the effect of high sulphide concentrations...

  11. Corrosion protection and steel-concrete bond improvement of prestressing strand.

    Science.gov (United States)

    2012-12-01

    Corrosion can lead to the premature deterioration and failure of transportation structures. In pre-stressed bridge structures corrosion is more severe, : leading to sudden failures when cracking is induced at pitting sites by tensile or compressive s...

  12. Corrosion protection of prestressing strand in transportation structures and strand-concrete bond improvement.

    Science.gov (United States)

    2012-12-01

    Corrosion can lead to the premature deterioration and failure of transportation structures. In pre-stressed bridge structures corrosion is more severe, : leading to sudden failures when cracking is induced at pitting sites by tensile or compressive s...

  13. Porous silicon-based direct hydrogen sulphide fuel cells.

    Science.gov (United States)

    Dzhafarov, T D; Yuksel, S Aydin

    2011-10-01

    In this paper, the use of Au/porous silicon/Silicon Schottky type structure, as a direct hydrogen sulphide fuel cell is demonstrated. The porous silicon filled with hydrochlorid acid was developed as a proton conduction membrane. The Au/Porous Silicon/Silicon cells were fabricated by first creating the porous silicon layer in single-crystalline Si using the anodic etching under illumination and then deposition Au catalyst layer onto the porous silicon. Using 80 mM H2S solution as fuel the open circuit voltage of 0.4 V was obtained and maximum power density of 30 W/m2 at room temperature was achieved. These results demonstrate that the Au/Porous Silicon/Silicon direct hydrogen sulphide fuel cell which uses H2S:dH2O solution as fuel and operates at room temperature can be considered as the most promising type of low cost fuel cell for small power-supply units.

  14. Acid volatile sulphide as an indicator for sediment toxicity?

    Energy Technology Data Exchange (ETDEWEB)

    Goyvaerts, M.P.; Brucker, N. De; Geuzens, P. [VITO, Mol (Belgium)

    1995-12-31

    The ratio SEM (Simultaneously Extracted Metals) to AVS (Acid Volatile Sulfide) is considered to be a measure for heavy metal bioavailability for benthic species. When the SEM/AVS ratio exceeds 1 heavy metal toxicity for the benthic organisms is expected. The correlation between the SEM/AVS and the toxicity for the bioluminescent bacterium Photobacterium phosphoreum is investigated. Freshwater sediments originating from different locations with high and low heavy metal contamination are tested. The toxicity test is performed according to the Solid Phase Microtox test (SPT). Unexpectedly, negative correlation between SEM/AVS and SPT toxicity was found (r = {minus}0.82, n = 44). However, sediments with a high sulphide content show a correlation between AVS and toxicity determined by SPT (r = 0.90, n = 18). Comparison with literature data and possible hypothesis for the discrepancies with the data will be presented. Additionally, a validation study concerning the AVS determination has been performed. Some of the aspects involved are: the sampling technique preserving the anoxic conditions of the sediment, the influence of the storage time and storage conditions on the AVS content of the standard conditions and the recovery of the metal sulphides used for the SEM calculation.

  15. 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.

  16. Multi-dimensional transport modelling of corrosive agents through a bentonite buffer in a Canadian deep geological repository.

    Science.gov (United States)

    Briggs, Scott; McKelvie, Jennifer; Sleep, Brent; Krol, Magdalena

    2017-12-01

    The use of a deep geological repository (DGR) for the long-term disposal of used nuclear fuel is an approach currently being investigated by several agencies worldwide, including Canada's Nuclear Waste Management Organization (NWMO). Within the DGR, used nuclear fuel will be placed in copper-coated steel containers and surrounded by a bentonite clay buffer. While copper is generally thermodynamically stable, corrosion can occur due to the presence of sulphide under anaerobic conditions. As such, understanding transport of sulphide through the engineered barrier system to the used fuel container is an important consideration in DGR design. In this study, a three-dimensional (3D) model of sulphide transport in a DGR was developed. The numerical model is implemented using COMSOL Multiphysics, a commercial finite element software package. Previous sulphide transport models of the NWMO repository used a simplified one-dimensional system. This work illustrates the importance of 3D modelling to capture non-uniform effects, as results showed locations of maximum sulphide flux are 1.7 times higher than the average flux to the used fuel container. Copyright © 2017. Published by Elsevier B.V.

  17. Influences of Corrosive Sulfur on Copper Wires and Oil-Paper Insulation in Transformers

    Directory of Open Access Journals (Sweden)

    Jian Li

    2011-10-01

    Full Text Available Oil-impregnated paper is widely used in power transmission equipment as a reliable insulation. However, copper sulphide deposition on oil-paper insulation can lead to insulation failures in power transformers. This paper presents the influences of copper sulfur corrosion and copper sulphide deposition on copper wires and oil-paper insulation in power transformers. Thermal aging tests of paper-wrapped copper wires and bare copper wires in insulating oil were carried out at 130 °C and 150 °C in laboratory. The corrosive characteristics of paper-wrapped copper wires and bare copper wires were analyzed. Dielectric properties of insulation paper and insulating oil were also analyzed at different stages of the thermal aging tests using a broadband dielectric spectrometer. Experiments and analysis results show that copper sulfide deposition on surfaces of copper wires and insulation paper changes the surface structures of copper wires and insulation paper. Copper sulfur corrosion changes the dielectric properties of oil-paper insulation, and the copper sulfide deposition greatly reduces the electrical breakdown strength of oil-paper insulation. Metal passivator is capable of preventing copper wires from sulfur corrosion. The experimental results are helpful for investigations for fault diagnosis of internal insulation in power transformers.

  18. Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

    Directory of Open Access Journals (Sweden)

    Helen R. Watling

    2015-07-01

    Full Text Available In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II and/or reduced inorganic sulphur compounds (RISC, such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity.

  19. The Corrosion Protection of Magnesium Alloy AZ31B

    Science.gov (United States)

    Danford, M. D.; Mendrek, M. J.; Mitchell, M. L.; Torres, P. D.

    1997-01-01

    Corrosion rates for bare and coated Magnesium alloy AZ31B have been measured. Two coatings, Dow-23(Trademark) and Tagnite(Trademark), have been tested by electrochemical methods and their effectiveness determined. Electrochemical methods employed were the scanning reference electrode technique (SRET), the polarization resistance technique (PR) and the electrochemical impedance spectroscopy technique (EIS). In addition, general corrosion and stress corrosion methods were employed to examine the effectiveness of the above coatings in 90 percent humidity. Results from these studies are presented.

  20. What's that smell? Hydrogen sulphide transport from Bardarbunga to Scandinavia

    Science.gov (United States)

    Grahn, Håkan; von Schoenberg, Pontus; Brännström, Niklas

    2015-09-01

    On Sep 9 2014 several incidences of foul smell (rotten eggs) were reported on the coast of Norway (in particular in the vicinity of Molde) and then on Sep 10 in the interior parts of county Västerbotten, Sweden. One of the theories that were put forward was that the foul smell was due to degassing of the Bardarbunga volcano on Iceland. Using satellite images (GOME-1,-2) of the sulphur dioxide, SO2, contents in the atmosphere surrounding Iceland to estimate flux of SO2 from the volcano and an atmospheric transport model, PELLO, we vindicate this theory: we argue that the cause for the foul smell was hydrogen sulphide originating from Bardarbunga. The model concentrations are also compared to SO2 concentration measurements from Muonio, Finland.

  1. Who farted? Hydrogen sulphide transport from Bardarbunga to Scandinavia

    CERN Document Server

    Grahn, Håkan; Brännström, Niklas

    2015-01-01

    On September 9 2014 several incidences of foul smell (rotten eggs) were reported on the coast of Norway (in particular in the vicinity of Molde) and then on September 10 in the interior parts of county V\\"asterbotten, Sweden. One of the theories that were put forward was that the foul smell was due to degassing of the Bardarbunga volcano on Iceland. Using satellite images (GOME-1,-2) of the sulphur dioxide, SO_2, contents in the atmosphere surrounding Iceland to estimate flux of SO_2 from the volcano and an atmospheric transport model, PELLO, we vindicate this theory: we argue that the cause for the foul smell was hydrogen sulphide originating from Bardarbunga. The model concentrations are also compared to SO_2 concentration measurements from Muonio, Finland.

  2. Bioleaching of pollymetallic sulphide concentrate using thermophilic bacteria

    Directory of Open Access Journals (Sweden)

    Vuković Milovan

    2014-01-01

    Full Text Available An extreme thermophilic, iron-sulphur oxidising bacterial culture was isolated and adapted to tolerate high metal and solids concentrations at 70°C. Following isolation and adaptation, the culture was used in a batch bioleach test employing a 5-l glass standard magnetic agitated and aerated reactor, for the bioleaching of a copper-lead-zinc collective concentrate. The culture exhibited stable leach performance over the period of leach operation and overall copper and zinc extractions higher than 97%. Lead sulphide is transformed into lead sulphate remaining in the bioleach residue due to the low solubility in sulphate media. Brine leaching of bioleach residue yields 95% lead extraction. [Projekat Ministarstva nauke Republike Srbije, br. 34023

  3. Magmatic Controls on the Genesis of Ni-Cu-PGE Sulphide Mineralisation on Mars

    Science.gov (United States)

    Baumgartner, R. J.; Fiorentini, M.; Baratoux, D.; Micklethwaite, S.; Sener, K.; McCuaig, C.

    2014-12-01

    Widespread igneous activity, which shows striking mineralogical, petrographical and chemical similarities with terrestrial komatiites and ferropicrites, intensely affected, reshaped and buried the primordial Martian crust. This study evaluates for the first time whether the broad igneous activity on Mars may have led to the formation of orthomagmatic Ni-Cu-PGE sulphide mineralisation similar to that associated with terrestrial komatiites and ferropicrites. Particular focus is laid on two different components of the Martian Ni-Cu-PGE sulphide mineral system: 1) the potential metal and sulphur fertility of source regions, and 2) the physical/chemical processes that enable sulphide supersaturation and metal concentration into an immiscible sulphide liquid. We show that potentially metal-rich Martian mantle melts likely reach sulphide saturation within 20-35 wt% of simple silicate fractionation; a value that is comparable to that of the terrestrial equivalents (i.e. ferropicrites and komatiites). However, the majority of terrestrial world-class Ni-Cu-PGE sulphide deposits originated by the assimilation of crustal sulphur-rich country rocks, allowing the attainment of sulphide supersaturation and liquid segregation during early stages of magma evolution. The high sulphur content in Martian crustal lithologies, ranging from sulphide bearing magmatic rocks to sulphate-rich regoliths and sedimentary deposits, imply that mantle melts potentially assimilated significant amounts of crustal sulphur during their ascent and emplacement. As a main outcome we show that channelled and fluid lava flows, which potentially emplaced and incised into these sulphur-rich crustal lithologies, are the most promising systems that may have led to the formation of Ni-Cu-PGE sulphide mineralisation on Mars.

  4. 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.

  5. Sulphide oxidation in ornamental slates: protective treatment with siloxanes

    Directory of Open Access Journals (Sweden)

    Rivas, T.

    2011-03-01

    Full Text Available In this work, we present the results of the measurement of the effectiveness of two silanes-siloxanes based products applied on roofing slates with the aim of slowing down the oxidation of the iron sulphide inclusions. The products were applied by immersion and spraying and also at different dilutions. The effectiveness of the treatments were evaluated by means of static contact angle measurements and water absorption coefficient variations; also, the durability under thermal cycles and the colour variations before treatment and before UVA exposition were tested. In all the cases, a very low product consumptions were obtained, due to the particular porous system of these rocks; also, any of the treatments increased the static angle. Nevertheless, the products tested remarkably increased the resistance of sulphides to the oxidation during thermal cycles without producing important changes in rock colour and also they have shown a good durability under UVA exposition

    En este trabajo se presentan los resultados de la medida de la eficacia de dos silanos-siloxanos aplicados en pizarras de techar con el objetivo de reducir la oxidación de las inclusiones de sulfuros de hierro. Los productos fueron aplicados por inmersión y spray a diferentes concentraciones. La efectividad de los tratamientos fue evaluada mediante la medida del ángulo de contacto estático y las variaciones del coeficiente de absorción de agua y su durabilidad mediante ciclos térmicos y de exposición a luz ultravioleta. A pesar del bajo consumo de ambos productos, debido al particular sistema poroso de estas rocas, y del bajo incremento del ángulo de contacto, ambos silanos-siloxanos incrementan notablemente la resistencia de los sulfuros a la oxidación durante los ciclos térmicos sin producir cambios relevantes en el color de la roca y muestran una aceptable durabilidad bajo la luz ultravioleta.

  6. Corrosion inhibiting organic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sasson, E.

    1984-10-16

    A corrosion inhibiting coating comprises a mixture of waxes, petroleum jelly, a hardener and a solvent. In particular, a corrosion inhibiting coating comprises candelilla wax, carnauba wax, microcrystalline waxes, white petrolatum, an oleoresin, lanolin and a solvent.

  7. 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....

  8. 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.

  9. Sulphide quinone reductase contributes to hydrogen sulphide metabolism in murine peripheral tissues but not in the CNS

    Science.gov (United States)

    Linden, DR; Furne, J; Stoltz, GJ; Abdel-Rehim, MS; Levitt, MD; Szurszewski, JH

    2012-01-01

    BACKGROUND AND PURPOSE Hydrogen sulphide (H2S) is gaining acceptance as a gaseous signal molecule. However, mechanisms regarding signal termination are not understood. We used stigmatellin and antimycin A, inhibitors of sulphide quinone reductase (SQR), to test the hypothesis that the catabolism of H2S involves SQR. EXPERIMENTAL APPROACH H2S production and consumption were determined in living and intact mouse brain, liver and colonic muscularis externa using gas chromatography and HPLC. Expressions of SQR, ethylmalonic encephalopathy 1 (Ethe1) and thiosulphate transferase (TST; rhodanese) were determined by RT-PCR and immunohistochemistry. KEY RESULTS In the colonic muscularis externa, H235S was catabolized to [35S]-thiosulphate and [35S]-sulphate, and stigmatellin reduced both the consumption of H235S and formation of [35S]-thiosulphate. Stigmatellin also enhanced H2S release by the colonic muscularis externa. In the brain, catabolism of H235S to [35S]-thiosulphate and [35S]-sulphate, which was stigmatellin-insensitive, partially accounted for H235S consumption, while the remainder was captured as unidentified 35S that was probably bound to proteins. Levels of mRNA encoding SQR were higher in the colonic muscularis externa and the liver than in the brain. CONCLUSIONS AND IMPLICATIONS These data support the concept that termination of endogenous H2S signalling in the colonic muscularis externa occurs via catabolism to thiosulphate and sulphate partially via a mechanism involving SQR. In the brain, it appears that H2S signal termination occurs partially through protein sequestration and partially through catabolism not involving SQR. As H2S has beneficial effects in animal models of human disease, we suggest that selective inhibition of SQR is an attractive target for pharmaceutical development. PMID:21950400

  10. 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....

  11. The Ioko-Dovyren layered massif (Southern Siberia, Russia): 2. Melt vs sulphide percolation process and modeling sulphide saturation in the parental magmas and original cumulates

    Science.gov (United States)

    Ariskin, Alexey; Danyushevsky, Leonid

    2013-04-01

    An important feature of the Dovyren intrusive complex [1] is its fertility due to the presence of massive sulphide ores near the bottom of the Ioko-Dovyren massif (YDM, SW and NE margins), as well as PGE-reefs in anorthosites from the Ol-gabbronorite zone in the centre [2]. These observations argue for the importance of downward percolation of sulphides through the porous space of cumulates and probable link of this process with upward migration of intercumulus melts at a post-cumulus stage. Indirectly, this is supported by the basic conclusion on the open-system behavior of the magma chamber [1]. A key aspect of these speculations is the onset of sulphide immiscibility in YDM parental magmas and the original cumulates. To reconstruct the sulphide saturation history, we applied a newly developed sulphide version of COMAGMAT (ver. 5.2 [3]) to the rocks from the chilled zone of YDM and underlying ultramafic sills, by simulating the course of their crystallization coupled with the SCSS calculations. Modeled crystallization trajectories evidence for under-saturated nature of the most primitive parental magmas (1310oC, Fo88) from which the chilled rocks were crystallized, whereas more evolved rocks from the sills demonstrate sulphide saturation starting from their initial temperature (1190oC, Fo85), see [1]. This correlates with the absence of sulphide ores in the central parts of the pluton and their occurrence in underlying ultramafics and YDM border series containing olivine Fo~85. Another set of calculations was carried out to demonstrate the effect of bulk Ni contents in Ol cumulate piles on the evolution of SCSS during their post-cumulus crystallization [3]. To achieve the goal, two calculations by the COMAGMAT-5.2 model were carried out. The first one involved modelling equilibrium crystallization for an initial mixture of Ol (Fo88) and intercumulus melt (~1320oC), with the starting composition corresponding to that of a bottom Pl-dunite (2315 ppm NiO, 0.030 wt

  12. Use of discriminant analysis to evaluate compositional controls of stratiform massive sulphide deposits in Canada

    National Research Council Canada - National Science Library

    Divi, S. R; Thorpe, R. I; Franklin, J. M

    1980-01-01

    Multiple discriminant analysis of Cu, Pb, Zn, Ag, and Au grades in Canadian stratiform massive sulphide deposits revealed that the relative grade values show a systematic variation with the geological...

  13. From lithotroph- to organotroph-dominant: directional shift of microbial community in sulphidic tailings during phytostabilization

    Science.gov (United States)

    Li, Xiaofang; Bond, Philip L.; van Nostrand, Joy D.; Zhou, Jizhong; Huang, Longbin

    2015-08-01

    Engineering microbial diversity to enhance soil functions may improve the success of direct revegetation in sulphidic mine tailings. Therefore, it is essential to explore how remediation and initial plant establishment can alter microbial communities, and, which edaphic factors control these changes under field conditions. A long-term revegetation trial was established at a Pb-Zn-Cu tailings impoundment in northwest Queensland. The control and amended and/or revegetated treatments were sampled from the 3-year-old trial. In total, 24 samples were examined using pyrosequencing of 16S rRNA genes and various chemical properties. The results showed that the microbial diversity was positively controlled by soil soluble Si and negatively controlled by soluble S, total Fe and total As, implying that pyrite weathering posed a substantial stress on microbial development in the tailings. All treatments were dominated by typical extremophiles and lithotrophs, typically Truepera, Thiobacillus, Rubrobacter; significant increases in microbial diversity, biomass and frequency of organotrophic genera (typically Nocardioides and Altererythrobacter) were detected in the revegetated and amended treatment. We concluded that appropriate phytostabilization options have the potential to drive the microbial diversity and community structure in the tailings toward those of natural soils, however, inherent environmental stressors may limit such changes.

  14. Corrosion in Electronics

    DEFF Research Database (Denmark)

    Ambat, Rajan; Gudla, Helene Virginie Conseil; Verdingovas, Vadimas

    2017-01-01

    and high density packing combined with the use of several materials, which can undergo electrochemical corrosion in the presence of water film formed due to humidity exposure and bias conditions on the PCBA surface. This article provides a short review of the corrosion reliability issues of electronics due...... to the use of electronics under varying humidity conditions. Important PCBA aspects, which are fundamental to the corrosion cell formation under humid conditions, are discussed. Effect of hygroscopic residues from the process and service and their role in assisting water film build up and corrosion...... is presented. Various failure modes resulting from the corrosion and influence factors are discussed including humid and gaseous conditions....

  15. Sulphide Resistance in the Cyanobacterium Microcystis aeruginosa: a Comparative Study of Morphology and Photosynthetic Performance Between the Sulphide-Resistant Mutant and the Wild-Type Strain.

    Science.gov (United States)

    Bañares-España, Elena; del Mar Fernández-Arjona, María; García-Sánchez, María Jesús; Hernández-López, Miguel; Reul, Andreas; Mariné, Mariona Hernández; Flores-Moya, Antonio

    2016-05-01

    The cyanobacterium Microcystis aeruginosa is a mesophilic freshwater organism, which cannot tolerate sulphide. However, it was possible to isolate a sulphide-resistant (S(r)) mutant strain that was able to survive in a normally lethal medium sulphide. In order to evaluate the cost of the mutation conferring sulphide resistance in the S(r) strain of M. aeruginosa, the morphology and the photosynthetic performance were compared to that found in the wild-type, sulphide-sensitive (S(s)) strain. An increase in size and a disrupted morphology was observed in S(r) cells in comparison to the S(s) counterpart. Phycoerythrin and phycocyanin levels were higher in the S(r) than in the S(s) cells, whereas a higher carotenoid content, per unit volume, was found in the S(s) strain. The irradiance-saturated photosynthetic oxygen-production rate (GPR max) and the photosynthetic efficiency (measured both by oxygen production and fluorescence, α(GPR) and α(ETR)) were lower in the S(r) strain than in the wild-type. These results appear to be the result of package effect. On the other hand, the S(r) strain showed higher quantum yield of non-photochemical quenching, especially those regulated mechanisms (estimated throughout qN and Y(NPQ)) and a significantly lower slope in the maximum quantum yield of light-adapted samples (Fv'/Fm') compared to the S(s) strain. These findings point to a change in the regulation of the quenching of the transition states (qT) in the S(r) strain which may be generated by a change in the distribution of thylakoidal membranes, which somehow could protect metalloenzymes of the electron transport chain from the lethal effect of sulphide.

  16. Hydrogen sulphide in cardiovascular system: A cascade from interaction between sulphur atoms and signalling molecules.

    Science.gov (United States)

    Wang, Ming-Jie; Cai, Wen-Jie; Zhu, Yi-Chun

    2016-05-15

    As a gasotransmitter, hydrogen sulphide exerts its extensive physiological and pathophysiological effects in mammals. The interaction between sulphur atoms and signalling molecules forms a cascade that modulates cellular functions and homeostasis. In this review, we focus on the signalling mechanism underlying the effect of hydrogen sulphide in the cardiovascular system and metabolism as well as the biological relevance to human diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Intercrystalline stress-corrosion cracking in Nb-stabilized austenitic steel used for core internals of a BWR; Interkristalline Spannungsrisskorrosion an Nb-stabilisiertem austenistischem Stahl in Kerneinbauten eines Siedewasserreaktors

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, O. [PreussenElektra AG, Hannover (Germany); Bruns, J. [PreussenElektra AG, Hannover (Germany); Wesseling, U. [Siemens/KWU, Erlangen (Germany); Kilian, R. [Siemens/KWU, Erlangen (Germany)

    1996-06-01

    Cracks detected in pipes for hot cooling water transport in German boiling water reactors have shown: titanium and Nb-stabilized materials are susceptible to intergranular stress-corrosion cracking in a hot water environment. In the Wuergassen nuclear power plant, cracks of this type were detected in the upper and lower support ring of the core shroud, and in the reinforcing rings of the upper and lower core support grid plates. The overall length of numerous single cracks was distributed over 75 up to 90% of the circumferential surface, sometimes crack depths amounted to approx. 30 mm. The cracks are caused by chromium carbide segregations at the grain interfaces. The corrosive agent primarily is H{sub 2}O{sub 2} formed by radiolysis. [Deutsch] Rissbefunde in mit heissem Reaktorwasser beaufschlagten Rohrleitungen deutscher Siedewasserreaktoren zeigten: Mit Titan- und Nb-stabilisierte Werkstoffe koennen unter den Wasserbedingungen interkristalline Spannungsrisskorrosion (IKSpRK) erleiden. Im Kernkraftwerk Wuergassen betrafen sie den oberen und unteren Auflagering des Kernmantels sowie die Verstaerkungsringe der oberen und unteren Gitterplatte. Die Gesamtlaenge zahlreicher Einzelrisse erstreckte sich auf 75 bis 90% des Umfanges, stichprobenweise wurden Risstiefen von etwa 30 mm ermittelt. Die Rissursache lag in Chromcarbid-Ausscheidungen auf den Korngrenzen. Das Korrosionspotential wird hauptsaechlich durch das radiolytisch enstehende H{sub 2}O{sub 2} gepraegt. (orig.)

  18. Corrosion of titanium: Part 1: aggressive environments and main forms of degradation.

    Science.gov (United States)

    Prando, Davide; Brenna, Andrea; Diamanti, Maria Vittoria; Beretta, Silvia; Bolzoni, Fabio; Ormellese, Marco; Pedeferri, MariaPia

    2017-11-11

    Titanium has outstanding corrosion resistance due to the external natural oxide protective layer formed when it is exposed to an aerated environment. Despite this, titanium may suffer different forms of corrosion in severe environments: uniform corrosion, pitting and crevice corrosion, hydrogen embrittlement, stress-corrosion cracking, fretting corrosion and erosion. In this first review, forms of corrosion affecting titanium are analyzed based on a wide literature review. For each form of corrosion, the mechanism and most severe environment are reported according to the current understanding.In the second part, this review will address the possible surface treatments that can increase corrosion resistance on commercially pure titanium: Electrochemical anodizing, thermal oxidation, chemical oxidation and bulk treatments such as alloying will be considered, highlighting the advantages of each technique.

  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. High temperature corrosion of nickel-base alloys in environments containing alkali sulphate

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Rachel; Flyg, Jesper; Caddeo, Sophie [Corrosion and Metals Research Institute, KIMAB, Stockholm (Sweden); Karlsson, Fredrik [Siemens Industrial Turbomachinery, Finspong (Sweden)

    2007-02-15

    This work is directed towards producing data to assist in lifetime assessment of components in gas turbines run in severely polluted industrial environments where the main corrosive species is SO{sub 2}, which can condense to form alkali sulphates. Corrosion rates have been measured for the base materials, in order to assess the worst-case scenario, in which cracks or other damage has occurred to the protective coating. The information is expected to be of value to manufacturers, owners and inspectors of gas turbines. Six nickel-base superalloys were subject to thermal cycles of 160 hours duration, and 0.8mg/cm{sup 2} of 20 mol % Na{sub 2}SO{sub 4} + 80mol% K{sub 2}SO{sub 4} was applied before each cycle. The test temperatures were 850 deg C and 900 deg C, with maximum test durations of 24 cycles and 12 cycles respectively. The metal loss was assessed by metallography of cross sections and the sulphidation attack was found to be very uneven. Mass change data indicated that the corrosion process was largely linear in character, and probability plots and estimations of the propagation rate of corrosion based on the linear growth assumption were produced. The performance of the alloys increased with increasing chromium content. The single crystal materials CMSX4 and MD2 showed such high corrosion rates that their use in severely contaminated industrial environments is considered inadvisable. The best performance was shown by Inconel 939 and Inconel 6203, so that even if cracks occur in the protective coating, a reasonable remaining lifetime can be expected for these materials. Sulphide formation occurred at the reaction front in all cases and mixed sulphides such as Ta-Ni or Ti-Nb sulphides were often present. The work has news value since very little long-term data is currently available for materials performance in severely sulphidising environments. The project goals in terms of exposures and metrology have been fully realised. Contributions have been made to the