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Sample records for stellite

  1. Friction surfaced Stellite6 coatings

    International Nuclear Information System (INIS)

    Rao, K. Prasad; Damodaram, R.; Rafi, H. Khalid; Ram, G.D. Janaki; Reddy, G. Madhusudhan; Nagalakshmi, R.

    2012-01-01

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: ► Stellite6 used as coating material for friction surfacing. ► Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. ► Finer and uniformly distributed carbides in friction surfaced coatings. ► Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  2. The Basics of Stellites in Machining Perspective

    Directory of Open Access Journals (Sweden)

    Md Shahanur Hasan

    2016-12-01

    Full Text Available Stellites are cobalt (Co-based superalloys available in two main combinations: (a a Tungsten (W group with composition of Co-Cr-W-C, and (b a Molybdenum (Mo group containing Co-Cr-Mo-C. Stellites possess outstanding corrosion resistance, oxidation resistance, wear resistance, heat resistance, and low magnetic permeability. Components made of stellites work well in highly corrosive environments and maintain these advantageous properties at elevated temperatures. Components made of stellites are widely used in the oil and gas, automotive, nuclear power, paper and pulp, chemical and petrochemical, refineries, automobile, aerospace and aircraft industries. By virtue of their nonmagnetic, anticorrosive and non-reactivity to human body-fluid properties, stellites are used in medical surgery and in surgical tools, tooth and bone implants and replacements, heart valves, and in heart pacemakers. The hardness range of stellites is from 32 to 55 HRC, which makes stellites brittle materials but they have a low Young’s modulus. Due to their high hardness, dense but non-homogeneous molecular structure and lower thermal conductivity, machining operations for parts made of stellites are extremely difficult, categorising stellites as difficult-to-machine materials like Ti-alloys, inconels, composites and stainless steels. Usually, machine components made of stellites are produced by a deposition method onto steel substrates instead of expensive solid stellite bars. The rough surfaces of deposited stellites are then finished by grinding, rather than some other economic machining process, which is costly and time-consuming, making stellite products very expensive. This paper provides a basic overview of stellites applicable in engineering, their significances and specific applications, advantages and disadvantages in respect of machining processes. A brief review on experimental research on economically rational cutting parameters for turning operations of

  3. Machinability of Stellite 6 hardfacing

    Directory of Open Access Journals (Sweden)

    Dudzinski D.

    2010-06-01

    Full Text Available This paper reports some experimental findings concerning the machinability at high cutting speed of nickel-base weld-deposited hardfacings for the manufacture of hot tooling. The forging work involves extreme impacts, forces, stresses and temperatures. Thus, mould dies must be extremely resistant. The aim of the project is to create a rapid prototyping process answering to forging conditions integrating a Stellite 6 hardfacing deposed PTA process. This study talks about the dry machining of the hardfacing, using a two tips machining tool and a high speed milling machine equipped by a power consumption recorder Wattpilote. The aim is to show the machinability of the hardfacing, measuring the power and the tip wear by optical microscope and white light interferometer, using different strategies and cutting conditions.

  4. Self-welding evaluation of stellite 6 and stellite 156 in flowing sodium

    International Nuclear Information System (INIS)

    Chang, J.Y.; Schrock, S.L.; Johnson, R.N.

    1977-01-01

    The self-welding behavior of two similar materials, Stellite 6 and Stellite 156, in sodium are discussed. The materials were tested at temperatures from 850 to 1140 0 F for time periods up to six-months while immersed in flowing sodium. Contact stresses ranged from 6000 psi to 16,000 psi on contact areas from 0.35 to 0.47 square inches. All separation tests to determine the extent of self-welding were conducted in a tensile mode. The surface morphologies of the samples before and after each test were measured. At temperatures of 1115 0 F and above, almost all the Stellite 6 specimens indicated a significant tendency toward self-welding within a relatively short period of time (one week). Stellite 156 couples also developed a strong self-weld bond at 1060 0 F after six-month exposure

  5. Radiation-induced corrosion of stellite-6

    International Nuclear Information System (INIS)

    Behazin, M.; Wren, J.C.

    2012-09-01

    Stellite-6 is a Co-based (58%) alloy that is used for components that require high wear-resistance, such as valve facings and ball bearings in nuclear reactors. In the reactor core, stable 59 Co can be neutron activated by absorption of a neutron to become the radioactive isotope, 60 Co. The 60 Co that is created constitutes a safety hazard for plant workers who have to perform maintenance on the reactor. One of the operational and safety issues in a nuclear reactor is the potential corrosion of Co-based alloys and the introduction of dissolved Co ions into the reactor core. While the corrosion of Stellite-6 has been studied its corrosion behaviour with ionizing radiation present has not been well established. Corrosion kinetics depend on both the aqueous redox conditions and the physical and chemical nature of the alloy surface. The high radiation fields present in a reactor core will cause water to decompose to a range of redox-active species (both highly oxidizing (e.g., ·OH, H 2 O 2 ) and highly reducing (e.g., ·eaq - , ·O 2 - )). These species can significantly influence corrosion kinetics. The effect of γ-radiation on the corrosion of Stellite-6 at pH 10.6 was investigated at temperatures ≤ 150 deg. C. Since the corrosion rate depends strongly on the type of oxide that is present on the material surface, the focus of this corrosion study was to establish the mechanism by which radiolysis affects the nature of the oxide that is present on Stellite-6. The results show that γ-radiation (at a dose rate of 5.5 kGy.h -1 ) increases the corrosion potential on Stellite-6 from -0.7 VSCE to 0.12 VSCE . The corrosion potential without irradiation present is in a potential range where oxidation is limited to the formation of a Co (OH) 2 and CoCr 2 O 4 outer oxide layer on a pre-existing Cr 2 O 3 film. The corrosion potential with irradiation is in a potential range where further oxidation of Co (OH) 2 to CoOOH also occurs. However, since CoOOH is less soluble than

  6. Status of Stellite 6 friction testing

    International Nuclear Information System (INIS)

    Watkins, J.C.; DeWall, K.G.

    1998-01-01

    For the past several years, researchers at the Idaho National Engineering and Environmental Laboratory, under the sponsorship of the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, have been investigating the performance of motor-operated valves subjected to design basis flow and pressure loads. Part of this research addresses the friction that occurs at the interface between the valve disc and the valve body seats during operation of a gate valve. In most gate valves, these surfaces are hardfaced with Stellite 6, a cobalt-based alloy. Analytical methods exist for predicting the thrust needed to operate these valves at specific pressure conditions. To produce accurate valve thrust predictions, the analyst must have a reasonably accurate, though conservative, estimate of the coefficient of friction at the disc-to-seat interface. One of the questions that remains to be answered is whether, and to what extent, aging of the disc and seat surfaces effects the disc-to-seat coefficient of friction. Specifically, does the environment in a nuclear plants piping system cause the accumulation of an oxide film on these surfaces that increases the coefficient of friction; and if so, how great is the increase? This paper presents results of specimen tests addressing this issue, with emphasis on the following: (1) the characteristics and thickness of the oxide film that develops on Stellite 6 as it ages; (2) the change in the friction coefficient of Stellite 6 as it ages, including the question of whether the friction coefficient eventually reaches a plateau; and (3) the effect in-service cycling has on the characteristics and thickness of the oxide film and on the friction coefficient

  7. Source term reduction at DAEC (including stellite ball recycling)

    International Nuclear Information System (INIS)

    Smith, R.; Schebler, D.

    1995-01-01

    The Duane Arnold Energy Center was seeking methods to reduce dose rates from the drywell due to Co-60. Duane Arnold is known in the industry to have one of the highest drywell dose rates from the industry standardized 'BRAC' point survey. A prime method to reduce dose rates due to Co-60 is the accelerated replacement of stellite pins and rollers in control rod blades due to their high stellite (cobalt) content. Usually the cobalt content in alloys of stellite is greater than 60% cobalt by weight. During the RFO-12 refueling outage at Duane Arnold, all of the remaining cobalt bearing control rod blades were replaced and new stellite free control rod blades were installed in the core. This left Duane Arnold with the disposal of highly radioactive stellite pins and rollers. The processing of control rod blades for disposal is a very difficult evolution. First, the velocity limiter (a bottom portion of the component) and the highly radioactive upper stellite control rod blade ins and rollers are separated from the control rod blade. Next, the remainder of the control rod blade is processed (chopped and/or crushed) to aid packaging the waste for disposal. The stellite bearings are then often carefully placed in with the rest of the waste in a burial liner to provide shielding for disposal or more often are left as 'orphans' in the spent fuel pool because their high specific activity create shipping and packaging problems. Further investigation by the utility showed that the stellite balls and pins could be recycled to a source manufacturer rather than disposed of in a low-level burial site. The cost savings to the utility was on the order of $200,000 with a gross savings of $400,000 in savings in burial site charges. A second advantage of the recycling of the stellite pins and rollers was a reduction in control in radioactive waste shipments

  8. Fabrication and Tests of M240 Machine Gun Barrels Lined with Stellite 25

    Science.gov (United States)

    2016-04-01

    ARL-TR-7662 ● APR 2016 US Army Research Laboratory Fabrication and Tests of M240 Machine Gun Barrels Lined with Stellite 25...Fabrication and Tests of M240 Machine Gun Barrels Lined with Stellite 25 by William S de Rosset and Sean Fudger Weapons and Materials Research...

  9. Influence of laser irradiation on deposition characteristics of cold sprayed Stellite-6 coatings

    Science.gov (United States)

    Li, Bo; Jin, Yan; Yao, Jianhua; Li, Zhihong; Zhang, Qunli; Zhang, Xin

    2018-03-01

    Depositing hard materials such as Stellite-6 solely by cold spray (CS) is challengeable due to limited ability of plastic deformation. In this study, the deposition of Stellite-6 powder was achieved by supersonic laser deposition (SLD) which combines CS with synchronous laser irradiation. The surface morphology, deposition efficiency, track shape of Stellite-6 coatings produced over a range of laser irradiation temperatures were examined so as to reveal the effects of varying laser energy inputting on the deposition process of high strength material. The microstructure, phase composition and wear/corrosion resistant properties of the as-deposited Stellite-6 coatings were also investigated. The experimental results demonstrate that the surface flatness and deposition efficiency increase with laser irradiation temperature due to the softening effect induced by laser heating. The as-deposited Stellite-6 tracks show asymmetric shapes which are influenced by the relative configuration of powder stream and laser beam. The SLD coatings can preserve the original microstructure and phase of the feedstock material due to relatively low laser energy inputting, which result in the superior wear/corrosion resistant properties as compared to the counterpart prepared by laser cladding.

  10. Failure Mechanism of a Stellite Coating on Heat-Resistant Steel

    Science.gov (United States)

    Wang, Dong; Zhao, Haixing; Wang, Huang; Li, Yuyan; Liu, Xia; He, Guo

    2017-09-01

    The Stellite 21 coating on the heat-resistant steel X12CrMoWVNbN10-1-1 (so-called COSTE) used in a steam turbine valve was found to be fatigue broken after service at around 873 K (600 °C) for about 8 years. In order to investigate the failure mechanism, a fresh Stellite 21 coating was also prepared on the same COSTE steel substrate by using the similar deposition parameters for comparison. It was found that the Stellite 21 coating was significantly diluted by the steel, resulting in a thin Fe-rich layer in the coating close to the fusion line. Such high Fe concentration together with the incessant Fe diffusion from the steel substrate to the coating during the service condition (about 873 K (600 °C) for long time) induced the eutectoid decomposition of the fcc α-Co(Fe,Cr,Mo) solid solution, forming an irregular eutectoid microstructure that was composed of the primitive cubic α'-FeCo(Cr,Mo) phase and the tetragonal σ-CrCo(Fe,Mo) phase. The brittle nature of such α'/ σ eutectoid microstructure contributed to the fatigue fracture of the Stellite 21 coating, resulting in an intergranular rupture mode.

  11. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V.

    2011-01-01

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to 60 Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to Stellite particles with the radiation field ranging from 3 R . h -1 to 20 R . h -1 . They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000 decays per min and cm 2 observed

  12. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V. [BARC Facilities, Kalpakkam, Tamil Nadu (India). Water and Steam Chemistry Div.

    2011-06-15

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to {sup 60}Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to Stellite particles with the radiation field ranging from 3 R . h{sup -1} to 20 R . h{sup -1}. They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000

  13. The effect of conditioning by permanganate on the dissolution behavior of stellite particles in organic complexing acid medium

    International Nuclear Information System (INIS)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Sukumar, A.A.; Raju, V.S.; Velmurugan, S.; Narasimhan, S.V.

    2004-01-01

    Radioactive hotspots found either in the primary heat transport circuit or auxiliary circuits of nuclear reactors are mainly due to particles containing activated cobalt. The main source of these particles are stellite alloys that are rich in cobalt and are used in primary cooling circuits in valves, pumps, etc. Due to either mechanical erosion or erosion coupled with corrosion under flow conditions (known as tribocorrosion), these stellite particles are released into the system. They are then activated by neutron absorption in the reactor core before being deposited on out-of-core surfaces, causing radiation exposure problems. In this paper, the possibility of dissolving stellite particles by using an oxidation-complexation process has been explored. Permanganate based reagents were evaluated for their efficiency in conditioning the stellite particles for their dissolution with organic acids. Permanganic acid was found to be the superior conditioning agent. Two alloys of stellite, viz. stellites no. 3 and no. 6, were studied with respect to their dissolution behavior

  14. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V.; Khandelwal, R.C.

    2010-01-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to 60 Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm 2 observed before decontamination

  15. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V., E-mail: svn@igcar.gov.in [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamilnadu (India); Khandelwal, R.C. [Kakrapara Atomic Power Station, KAPS, Surat, Gujarat (India)

    2010-07-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to {sup 60}Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm{sup 2} observed

  16. Rheology of StelliteTM 21 Alloy in Semi-Solid State

    Directory of Open Access Journals (Sweden)

    Sołek K.

    2016-12-01

    Full Text Available The main objective of this study was to conduct an analysis of the rheological properties of StelliteTM 21 alloy in the semi-solid state, as the results could be used for identifying the appropriate temperature range for thixoforming of this alloy, and a secondary objective of the experimental work was the development of mathematical model of the alloy’s apparent viscosity. Such viscosity models are necessary for numerical simulations of the thixoforming processes. The StelliteTM 21 alloy exhibits high hardness and thus shaping in the semi-solid state is promising route of production of parts from this alloy. Within the confines of experimental work the measurement methods of the rheological properties at high temperatures was developed. They are based on the use of specially designed viscometer equipped with high temperature furnace.

  17. Microstructure and sliding wear properties of HVOF sprayed, laser remelted and laser clad Stellite 6 coatings

    Czech Academy of Sciences Publication Activity Database

    Houdková, Š.; Pala, Zdeněk; Smazalová, E.; Vostřák, M.; Česánek, Z.

    2017-01-01

    Roč. 318, May (2017), s. 129-141 ISSN 0257-8972. [International Meeting on Thermal Spraying (RIPT)/7./. Limoges, 09.12.2015-11.12.2015] Institutional support: RVO:61389021 Keywords : Stellite 6 * HVOF * Laser remelting * Laser clad * Wear * Phase transformation Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 2.589, year: 2016 http://www.sciencedirect.com/science/ article /pii/S0257897216308817

  18. Cavitation Erosion of Electro Spark Deposited Nitinol vs. Stellite Alloy on Stainless Steel Substrate

    Science.gov (United States)

    2015-07-15

    lower proportion of carbon. The lower carbon content of SS-316L allows lower carbide precipitation for welding . Online Metals SS-2205 Duplex ...erosion, per ASTM G32. As a comparison, a known erosion-resistant, weld -friendly alloy called Stellite 6® was ESD’d and its cavitation erosion resistance...Microscopy was conducted to examine the metallurgical bond established by the ESD process. As a comparison, a known erosion resistant, weld

  19. Critical size of defaults inducing fast fracture of deposit stellite on a valve gate

    International Nuclear Information System (INIS)

    Boneh, B.; Gilles, P.; Champomier, F.; Abisror, A.

    1986-10-01

    The present study has been made to determine if, in the case of a valve gate, transversal cracks are the result of fatigue propagation or the result of fast fracture. The author shows that only a transversal crack, with a size up to 0.7 mm, induces a fast fracture and shows also that, at equal size, a crack located under the stellite is not also injurious than a transversal crack [fr

  20. Friction and wear behavior of Colmonoy and Stellite alloys in sodium environment

    International Nuclear Information System (INIS)

    Kanoh, S.; Mizobuchi, S.; Atsumo, H.

    1976-01-01

    A description is given of a series of experiments in sodium environment for the research and development of friction and wear resistant material used for the sliding components of sodium cooled fast breeder reactor. The study relates to the friction and wear characteristics of nickel-base alloy, Colmonoy, and cobalt-base alloy, Stellite, with respect to temperature, load, sliding velocity, sliding mode, and sodium flushing. The friction behavior of these alloys in sodium is compared with that in argon

  1. Powder injection molding of Stellite 6 powder: Sintering, microstructural and mechanical properties

    International Nuclear Information System (INIS)

    Gülsoy, H. Özkan; Özgün, Özgür; Bilketay, Sezer

    2016-01-01

    The purpose of this study was to produce Co-based Stellite 6 superalloy components by using the method of Powder Injection Molding (PIM) and to characterize the microstructural and mechanical properties of the produced components. The experimental studies were started through the formation of feedstock by mixing Stellite 6 powder with a multicomponent binder system. Prepared feedstock was formed by utilizing powder injection molding technique. Then the molded samples were subjected to the solvent and thermal debinding processes. Different sintering cycles were applied to the raw components for the purpose of determining the optimum sintering conditions. The densities of the sintered components were determined in accordance with the Archimedes' principle. The microstructural characterization was performed through scanning electron microscope (SEM) analysis, energy dispersive spectrometry (EDS) analyses, and X-ray diffraction (XRD) analysis. Hardness measurement and tensile test were conducted in order to determine the mechanical properties. The results illustrated that the injection molded Stellite 6 components were composed of fine and equiaxed grains, plenty of carbide precipitates exhibiting homogenous distribution throughout the microstructure formed at the grain boundaries and thus the mechanical properties were considerably high.

  2. Laser surface melting of 10 wt% Mo alloyed hardfacing Stellite 12 plasma transferred arc deposits: Structural evolution and high temperature wear performance

    Science.gov (United States)

    Dilawary, Shaikh Asad Ali; Motallebzadeh, Amir; Afzal, Muhammad; Atar, Erdem; Cimenoglu, Huseyin

    2018-05-01

    Laser surface melting (LSM) process has been applied on the plasma transferred arc (PTA) deposited Stellite 12 and 10 wt% Mo alloyed Stellite 12 in this study. Following the LSM process, structural and mechanical property comparison of the LSM'ed surfaces has been made. Hardness of the LSM'ed surfaces was measured as 549 HV and 623 HV for the Stellite 12 and Stellite 12 + 10 wt% Mo deposits, respectively. Despite their different hardness and structural features, the LSM'ed surfaces exhibited similar tribological performance at room temperature (RT), where fatigue wear mechanism operates. However, the wear at 500 °C promotes tribo-oxide layer formation whose composition depended on the alloying with Mo. Thus, addition of 10 wt% Mo into Stellite 12 PTA deposit has remarkably enhanced the high temperature wear performance of the LSM'ed surface as a result of participation of complex oxide (CoMoO4) in tribo-oxide layer.

  3. Optimization of pulsed TIG cladding process of stellite alloy on carbon steel using RSM

    Energy Technology Data Exchange (ETDEWEB)

    Madadi, F., E-mail: f.madadi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Ashrafizadeh, F. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Shamanian, M., E-mail: shamanian@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of)

    2012-01-05

    Highlights: > This study is useful to optimize the welding process variables in order to control the heat input and cooling rates such that the hardness and dilution of the clad could be estimated. > Central composite rotatable design technique with five-level, four-factor full-factorial design matrix and mathematical models was used to predict hardness and dilution of pulsed gas tungsten arc weld cladding of stellite6 on carbon steel with high accuracy. > The welding current is an effective parameter affecting heat input and melting. In this regard, it is the most important process parameter which influences the dilution. Increase welding current leads to increase in dilution percentage and vice versa. The effect of percentage on time is less important when compared to the other factors. > The results predicted by mathematical models were close to those obtained by experiments. The confirmation tests also indicated high correlation between the mentioned values. > All of the chosen pulse GTAW parameters were significant and showed a noticeable influence on clad dilution. - Abstract: Stellite 6 is a cobalt-base alloy which is resistant to wear and corrosion and retains these properties at high temperatures. The exceptional wear resistance of Stellite 6 is mainly due to the unique inherent characteristics of the hard carbides dispersed in a Co-Cr alloy matrix. In this study, pulsed tungsten inert gas (TIG) cladding process was carried out to deposit Stellite 6 on plain carbon steel plate. The beneficial effects of this cladding process are low heat input, low distortion, controlled weld bead volume, less hot cracking tendency, less absorption of gases by weld pool and better control of the fusion zone. The dilution effect is a key issue in the quality of cladded layers and, in this regard, the pulsed current tungsten inert gas (PCTIG) was performed to decrease excess heat input and melting of substrate. This paper deals with the investigation of the hardness and

  4. Microstructure and wear behavior of stellite 6 cladding on 17-4 PH stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Gholipour, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, M., E-mail: shamanian@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Ashrafizadeh, F. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-04-07

    Research highlights: > The microstructure of the surface layer consisted of carbides embedded in a Co-rich solid solution with dendritic structure. Primary phases formed during the process were identified as Co(FCC) and lamellar eutectic phases (M{sub 23}C{sub 6}, M{sub 6}C, Cr{sub 7}C{sub 3}). > Microhardness profiles showed that hardness increases from interface to the coating surface. This is due to the finer size of the grains at coating surface in comparison to that at interface and also diffusion of Fe adjacent to the interface. > The delamination was suggested as the dominant mechanism of the wear. In this regard, plate-like wear debris consisted of voids and cracks. In addition, due to increase in surface temperature, Cr{sub 2}O{sub 3} oxide phase was formed during wear tests. - Abstract: This paper deals with the investigation of the microstructure and wear behavior of the stellite 6 cladding on precipitation hardening martensitic stainless steel (17-4PH) using gas tungsten arc welding (GTAW) method. 17-4 PH stainless steel is widely used in oil and gas industries. Optical metallography, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to study the microstructure and wear mechanisms. X-ray diffraction analysis was also used to identify phases formed in the coating. The results showed that the microstructure of the surface layer consisted of carbides embedded in a Co-rich solid solution with a dendritic structure. In addition, the dendritic growth in the coating was epitaxial. Primary phases formed during the process were Co (fcc), Co (hcp), lamellar eutectic phases, M{sub 23}C{sub 6} and Cr{sub 7}C{sub 3} type carbides. The results of the wear tests indicated that the delamination was the dominant mechanism. So, it is necessary to apply an inter-layer between the substrate and top coat.

  5. Laser Clad and HVOF-Sprayed Stellite 6 Coating in Chlorine-Rich Environment with KCl at 700 °C.

    Czech Academy of Sciences Publication Activity Database

    Pala, Z.; Bai, M.; Lukáč, František; Hussain, T.

    2017-01-01

    Roč. 88, 5-6 (2017), s. 749-771 ISSN 0030-770X Institutional support: RVO:61389021 Keywords : Stellite 6 * KCl * High-temperature corrosion * HVOF * Laser cladding Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 1.196, year: 2016 https://link.springer.com/article/10.1007/s11085-017-9776-7

  6. Measuring Dilution and Wear for Laser Cladding of Stellite 6 Produced on a P91 Steel Substrate using Two Different Heat Inputs

    Directory of Open Access Journals (Sweden)

    Kusmoko Alain

    2016-01-01

    Full Text Available Stellite 6 was deposited by laser cladding on a P91 substrate with energy inputs of 1 kW (P91-1 and 1.8 kW (P91–1.8. The chemical compositions, microstructures and surface roughnesses of these coatings were characterized by atomic absorption spectroscopy, scanning electron microscopy and atomic force microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was evaluated using a pin-on-plate (reciprocating wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the P91 steel substrate with the lower heat input (P91–1. Further, the Stellite coating for P91-1 was significantly harder than that obtained for P91–1.8. The wear test results indicated that the weight loss for P91–1 was much lower than for P91–1.8. The surface topography data indicated that the surface roughness for P91-1 was much lower than for P91–1.8. The measurements of dilution and carbon content showed that P91–1 has lower dilution and higher concentration of carbon than P91–1.8. It is concluded that the lower hardness of the coating for P91–1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating and the lower hardness of the coating for P91-1.8 was due to higher level of dilution and lower concentration of carbon.

  7. Estimation of the Thickness and the Material Combination of the Thermal Stress Control Layer (TSCL) for the Stellite21 Hardfaced STD61 Hot Working Tool Steel Using Three-Dimensional Finite Element Analysis

    International Nuclear Information System (INIS)

    Park, Na-Ra; Ahn, Dong-Gyu; Oh, Jin-Woo

    2014-01-01

    The research on a thermal stress control layer (TSCL) begins to undertake to reduce residual stress and strain in the vicinity of the joined region between the hardfacing layer and the base part. The goal of this paper is to estimate the material combination and the thickness of TSCL for the Stellite21 hardfaced STD61 hot working tool steel via three-dimensional finite element analysis (FEA). TSCL is created by the combination of Stellite21 and STD61. The thickness of TSCL ranges from 0.5 mm to 1.5 mm. The influence of the material combination and the thickness of TSCL on temperature, thermal stress and thermal strain distributions of the hardfaced part have been investigated. The results of the investigation have been revealed that a proper material combination of TSCL is Stellite21 of 50 % and STD61 of 50 %, and its appropriate thickness is 1.0 mm

  8. Metallurgical and mechanical properties of Inconel 600 and stellite; Estudio del comportamiento mecanico-metalurgico de alceacion inconel 600 y estelita

    Energy Technology Data Exchange (ETDEWEB)

    Cstillo, Martin; Villa, Gabriel; Vite, Manuel [Instituto Politecnico Nacional, Mexico D.F. (Mexico); Palacios, Francisco [Instituto Nacional de Investigacion Nuclear (ININ), Estado de Mexico (Mexico); Hernandez, Luis H; Urriolagoita, Guillermo [Instituto Politecnico Nacional, Mexico D.F. (Mexico)

    2005-01-15

    The present work studies the metallurgical and mechanical properties of two alloys, Inconel 600 and stellite, which are within the group of high hardness alloys or superalloys, which are deposited through the electrical weld process to the metallic arc with coated electrode (SMAW) and thereinafter analyzed through electron microscopy, diffractometry and abrasion, Impact and hardness test. The relationship between the microstructure and the final properties of the coating (hardness and abrasion wear resistance) was observed. [Spanish] Este trabajo presenta el estudio sobre las propiedades metalurgicas y mecanicas de dos aleaciones, inconel 600 y estelita, clasificadas dentro del grupo de aleaciones de alta dureza o superaleaciones; las cuales fueron depositadas mediante el proceso de soldadura electrica al arco metalico con electrodo revestido (SMAW) y fueron analizadas mediante microscopia electronica (SEM), difractometria pruebas de abrasion, impacto y dureza. Se observo la relacion entre la microstructura y las propiedades del recubrimiento, como son: dureza, resistencia a la abrasion, resistencia al impacto, ente otras.

  9. Optimización del proceso de aporte de recubrimientos anticorrosión de Stellite 6 producidos mediante plaqueado láser

    Directory of Open Access Journals (Sweden)

    Vicario, I.

    2009-02-01

    mediante la técnica de plaqueado láser para producir recubrimientos anti-corrosión empleando aleación de Co Stellite 6 en polvo sobre un substrato de acero C45 (AISI 1045. Posteriormente, se lleva a cabo un estudio de las características frente a la corrosión del recubrimiento final obtenido y de su correlación con los parámetros de aporte empleados.

  10. Recubrimiento de Stellite 6 sobre acero inoxidable realizado con láser de CO2 para válvulas de escape de motores diesel

    Directory of Open Access Journals (Sweden)

    Cadenas, M.

    2002-12-01

    Full Text Available To reduce the recovery or the replacement costs of diesel engine exhaust valves, they are manufactured with an economic base material, and a coating which is deposited on the seat valve in order to reach high hardness and good impact, corrosion and high temperature wear resistance (>550 °C and without lubrication. In this work, appropriate laser cladding parameters have been determined to obtain Stellite 6 coatings over AISI 304 steel (as plane test specimens and SAE EV8 steel (as valves substrates. One and two superimposed tracks were deposited on the seat valves, and modifying the laser power as a function of the rotated angle at the beginning and the end of the circular tracks, pores and cracks have been minimized and the thickness of the track were made uniform. Hardness, dilution and final microstructure of the different coatings have been analysed. A 10 % dilution and 550 HV in the tracks over plane test specimens was observed, while valves with one track showed 25 % and 430 HV respectively. With two superimposed tracks the hardness was up to 470 HV in the upper track.

    Para abaratar el coste de recuperación o sustitución de válvulas de escape en motores diesel, estas se fabrican con un material base económico, recubriéndose el asiento de la válvula con otro material al que se exigirá elevada dureza y buena resistencia al impacto, a la corrosión y al desgaste erosivo en caliente (>550 °C y sin lubricación. Partiendo de esta idea, en el presente trabajo se han determinado los parámetros adecuados para realizar, mediante la técnica de plaqueado láser, un recubrimiento con Stellite 6, sobre sustratos de acero AISI 304 (probetas planas y SAE EV8 (válvulas reales. Sobre las válvulas, se depositaron uno y dos cordones superpuestos, se minimizó la presencia de poros y grietas, modificando el grado de solape inicial y final de los cordones circulares y la potencia en función del ángulo girado. Así, se

  11. Stellite failure on a P91 HP valve - failure investigation and modelling of residual stresses

    DEFF Research Database (Denmark)

    Thorborg, Jesper; Hald, John; Hattel, Jesper Henri

    2006-01-01

    , and this provides a tool for process modification in order to minimize the risk for future breakdown. Both classical time independent and time dependent plasticity models have been used to describe the different material behaviours during the different process steps. The description of the materials is highly...

  12. Optimization of the deposition process of corrosion resistant Stellite 6 coatings produced by laser cladding; Optimizacion del proceso de aporte de recubrimientos anticorrosion de Stellite 6 producidos mediante plaqueado laser

    Energy Technology Data Exchange (ETDEWEB)

    Vicario, I.; Soriano, C.; Sanz, C.; Bayon, R.; Leunda, J.

    2009-07-01

    Laser cladding is one of the most efficient surface treatment technologies in the industry. It uses a laser heat source to deposit a thin layer of a desired material on a moving substrate, whose properties have to be improved, achieving a metallurgical bonding between them with low heat affected zone and low dilution, compared to other conventional technologies such as PTA, TIG welding or thermal Spraying. In this sense, it is remarkable that there are 3 main application fields for laser cladding technology: restoration of refurbishment of damaged parts, surface coating against corrosion or wear, and rapid proto typing. the present work described a study of the optimization of the laser cladding of Co based coatings (Diamalloy 4060NS) on medium carbon steel C45 (AISI 1945). After laser treatment, the surface of the substrate materials is improved in terms of resistance against corrosion; this confirmed in the analysis performed afterwards. it is also shown that the corrosion barrier properties have direct correlation with the laser cladding variables. (Author) 10 refs.

  13. Étude de défaut trouvé dans des tubes centrifugés de stellite 6B

    OpenAIRE

    Villar Echeverría, Alejandro

    2014-01-01

    Les superalliages sont des alliages employés pour travailler à hautes températures tout en maintenant stabilité dimensionnelle et résistance mécanique et à la corrosion. Ils sont utilisés dans les domaines de l'aéronautique, l’industrie navale et médicale entre autres. Parmi les différents types de superalliages existants (base nickel, base cobalt et base nickel-fer), on travaillera dans cette étude avec des superalliages base cobalt. Ces alliages sont connus communément sous le nom de Stelli...

  14. Improved hardness of laser alloyed X12CrNiMo martensitic stainless steel

    CSIR Research Space (South Africa)

    Adebiyi, DI

    2011-07-01

    Full Text Available The improvement in hardness of X12CrNiMo martensitic stainless steel laser alloyed with 99.9% pure titanium carbide, stellite 6 and two cases of premixed ratio of titanium carbide and stellite 6 [TiC (30 wt.%)- stellite 6 (70 wt.%) and TiC (70 wt...

  15. RA Reactor operation and maintenance (I-IX), part VIII, Task 3.08/05, Decontamination of the reactor

    International Nuclear Information System (INIS)

    Zecevic, V.

    1963-12-01

    Permanent increase of radiation in the heavy water system was noticed during first three year of the RA reactor operation, even when the reactor was shutdown. It was found that there was no failure of the fuel element cladding. Radioactive cobalt was found in the heavy water which was rather strange. During repair of the heavy water system, it has been found that stellite was used for coating the heavy water pumps. Since stellite is a cobalt alloy, this could have been the source of radioactive cobalt in the heavy water. The stellite coating was damaged due to friction and particle of cobalt appeared in the coolant, they were activated since they were in the core. decontamination of the heavy water and the heavy water coolant loop was a must . Beside the detailed report on the contamination and decontamination of the heavy water system this volume includes 14 annexes describing the investigation of the event and the whole procedure of decontamination

  16. RA Reactor operation and maintenance (I-IX), part VIII, Task 3.08/05, Decontamination of the reactor; Pogon i odrzavanje reaktora (I-IX), VIII Deo, Zadatak 3.08/05 Dekontaminacija reaktora

    Energy Technology Data Exchange (ETDEWEB)

    Zecevic, V [Institute of Nuclear Sciences Boris Kidric, Reaktor RA, Vinca, Beograd (Serbia and Montenegro)

    1963-12-15

    Permanent increase of radiation in the heavy water system was noticed during first three year of the RA reactor operation, even when the reactor was shutdown. It was found that there was no failure of the fuel element cladding. Radioactive cobalt was found in the heavy water which was rather strange. During repair of the heavy water system, it has been found that stellite was used for coating the heavy water pumps. Since stellite is a cobalt alloy, this could have been the source of radioactive cobalt in the heavy water. The stellite coating was damaged due to friction and particle of cobalt appeared in the coolant, they were activated since they were in the core. decontamination of the heavy water and the heavy water coolant loop was a must . Beside the detailed report on the contamination and decontamination of the heavy water system this volume includes 14 annexes describing the investigation of the event and the whole procedure of decontamination.

  17. Decay heat and activity of the structural materials of the fuel and blanket assemblies of the second and third core of KNK II

    International Nuclear Information System (INIS)

    Winterhagen, D.

    1986-06-01

    The decay heat and activity caused by structural materials have been calculated for the fuel assemblies of KNK II (second and third core) with a residence time of 720 equivalent full-power days (efpd) and the blanket assemblies with 1880 efpd. The values are given for the different zones of the assemblies (head, active zone, fission gas plenum, foot and stellite area) for decay times from 1 to 20 years. For decay times beyond 2 years more than 80 % of the decay heat are caused by the Co60-decay, more than 60 % of which result from the stellite in the foot area [de

  18. Comparative metallurgical study of thick hard coatings without cobalt

    International Nuclear Information System (INIS)

    Clemendot, F.; Van Duysen, J.C.; Champredonde, J.

    1992-07-01

    Wear and corrosion of stellite type hard coatings for valves of the PWR primary system raise important problems of contamination. Substitution of these alloys by cobalt-free hard coatings (Colmonoy 4 and 4.26, Cenium 36) should allow to reduce this contamination. A comparative study (chemical, mechanical, thermal, metallurgical), as well as a corrosion study of these coatings were carried out. The results of this characterization show that none of the studied products has globally characteristics as good as those of grade 6 Stellite currently in service

  19. Effect of Heat Treatment on the Microstructure and Properties of HVOF-Sprayed Co-Cr-W Coating

    Czech Academy of Sciences Publication Activity Database

    Houdková, Š.; Smazalová, E.; Pala, Zdeněk

    2016-01-01

    Roč. 25, č. 3 (2016), s. 546-557 ISSN 1059-9630 Institutional support: RVO:61389021 Keywords : ASTM * G-65ASTM * Co-Cr-W * heat treatment * HVOF * Stellite 6 * wear Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.488, year: 2016

  20. Wear Test Results of Candidate Materials for the OK-542 Towed Array Handling Machine Level Winder

    Science.gov (United States)

    1994-12-29

    10 6. Wear Testing Photograph B ....................................................... .11 7. Clad Inconel 625 ...interfere with this wear test. Other materials that were tested included Inconel 625 , Titanium, 304 Stainless, 316 Stainless, and Ni-Al-Br. All of these...Stainless Steel, Inconel 625 , Nickel-Aluminum-Bronze, and Titanium. The specialty materials: Inconel 625 , Monel, Stainless and Stellite, were clad-welded

  1. Surface engineering with lasers : an application to Co-base materials

    NARCIS (Netherlands)

    de Hosson, J.T.M.; de Mol van Otterloo, J.L.; Boerstoel, B.M.; Huis in 't Veld, A.J.; Sarton, LAJ; Zeedijk, HB

    1997-01-01

    The present paper concentrates on the applications of CO2 laser treatments to enhance fretting wear properties of stainless steel. Stainless steel 316 is used as substrate material. Powder particles of the various stellites with sizes ranging between 45 and 125 mu m are fed onto the surface. It was

  2. Hard hardfacing by welding in the manufacture of valves; Problem Cobalt, alternatives, advantages, disadvantages

    International Nuclear Information System (INIS)

    Piquer Caballero, J.

    2014-01-01

    Alloys of recharge usually used in the field of the valves are base alloys cobalt (stellite), but in the field of nuclear power plants, due to radioactive activation of the cobalt, there is a growing trend to replace these alloys with other calls cobalt free . In this paper we will explore the most frequent and will be deducted the relevant advantages and disadvantages of these, in comparison with base alloys cobalt. (Author)

  3. Effect of tungsten-187 in primary coolant on dose rate build-up in Vandellos 2

    International Nuclear Information System (INIS)

    Fernandez Lillo, E.; Llovet, R.; Boronat, M.

    1994-01-01

    The present work proposes a relationship between the Cobalt-60 piping deposited activity and the relatively high levels of Tungsten-187 in the coolant of Vandellos 2. The conclusions of this work can be applicable to other plants, since it proposes a tool to estimate and quantify the contribution of stellite to the generation of Cobalt-60 and the radiation dose build-up. (authors). 7 figs., 6 refs

  4. Chromium Elimination and Cannon Life Extension for Gun Tubes

    Science.gov (United States)

    2012-08-30

    the use of hexavalent chromium (VI) in the production of cannon barrels by developing a cost effective environmentally friendly Explosive Bonding...erosion- resistant chrome cobalt alloy matrix with 15% tungsten. Stellite is used as M60 machine gun barrel liner. Tantalum Cobalt Tungsten...Grounds (YPG) Preliminary proof of principle endurance testing at YPG shows promising results when conducted side by side to a chrome plated

  5. Cost Estimate for Gun Liner Emplacement

    Science.gov (United States)

    2011-08-01

    excellent material to resist wear and erosion in gun tubes, it is applied by an electrolytic process that involves hexavalent chromium, a known carcinogen...A recent Department of Defense memorandum has strongly urged that, wherever possible, processes involving hexavalent chromium be eliminated from...might be affordable.) Other refractory metals, such as the Stellite series, BioDur CCM* (a cobalt, chrome , molybdenum alloy), or niobium are less

  6. Hard hardfacing by welding in the manufacture of valves; Problem Cobalt, alternatives, advantages, disadvantages; Recargues Duros por Soldadura en la Fabricacion de Valvulas ; el Problema del Cobalto, alternativas, ventajas, inconvenientes

    Energy Technology Data Exchange (ETDEWEB)

    Piquer Caballero, J.

    2014-07-01

    Alloys of recharge usually used in the field of the valves are base alloys cobalt (stellite), but in the field of nuclear power plants, due to radioactive activation of the cobalt, there is a growing trend to replace these alloys with other calls cobalt free . In this paper we will explore the most frequent and will be deducted the relevant advantages and disadvantages of these, in comparison with base alloys cobalt. (Author)

  7. Hard alloys testing-machine for values of PWR primary coolant circuits

    International Nuclear Information System (INIS)

    Campan, J.L.; Sauze, A.

    1980-01-01

    Testing of valve parts or material used in valve fabrication and particularly seizing conditions in friction of plane surfaces coated with hard alloys of the type stellite. The testing equipment called Marguerite is composed of a hot pressurized water loop in conditions similar to PWR primary coolant circuits (320 0 C, 150 bars) and a testing-machine with measuring instruments. Testing conditions and samples are described [fr

  8. Report on measurements at the pump Avala - Annex 7

    International Nuclear Information System (INIS)

    Nikolic, M.

    1963-01-01

    Visual inspection and measuring results have shown that the surface of the upper pump bearing is much more worn-out than the lower radial bearing. This has proved that most of the cobalt (contained in the stellite alloy) came from the upper pump bearings. It could be stated that about 60 grams of cobalt from the upper pump bearings could come into the coolant system [sr

  9. Electrospark deposition for die repair

    Directory of Open Access Journals (Sweden)

    J. Tušek

    2012-01-01

    Full Text Available The electrospark deposition is a process for surfacing of hard metal alloys, e.g. carbides and stellites, on the surfaces of new or old machine elements. In this process, a high current is conducted through an oscillating electrode and a substrate for a very short period of time. In the paper, the process is described and the thickness of deposited layer, chemical composition, dilution rate and the layer roughness are determined.

  10. Application of Moessbauer spectroscopy to study corrosion

    International Nuclear Information System (INIS)

    Ramshesh, V.; Ravichandran, K.; Venkateswarlu, K.S.

    1976-01-01

    The system components in a nuclear power station include steel, stainless steel and various alloys such as Monel, Inconel, Stellite etc. Usually water/heavy water used as the coolant flows at high temperatures and pressures. Under such conditions the interaction of system components with the coolant produces a host of corrosion products. The deposition of such products is essential. This report attempts to review the salient features of identification of such corrosion products using Moessbauer spectroscopy. (author)

  11. Analysis of structure-tectonic pattern within the 'Degelen' massif conformably to conditions of radionuclide migration in ground water

    International Nuclear Information System (INIS)

    Gorbunova, Eh.M.; Ivanchenko, G.N.; Godunova, L.D.

    2005-01-01

    Major orientation of radiation monitoring on the Semipalatinsk test site lies in direction of common regularities for formation and distribution of radioactive contamination. Zones, within the 'Degelen' technical area. of hydrogeological active faults are patly subjected to impact of underground explosions. Data of computer-aided decryption of a stellite image by means of program package LESSA allow specification of para-genesis structures standing as probabilistic pathways of radionuclide migration. (author)

  12. Prevention of crack initiation in valve bodies under thermal shock

    Energy Technology Data Exchange (ETDEWEB)

    Delmas, J.; Coppolani, P.

    1996-12-01

    On site and testing experience has shown that cracking in valves affects mainly the stellite hardfacing on seats and discs but may also be a concern for valve bodies. Metallurgical investigations conducted by EDF laboratories on many damaged valves have shown that most of the damage had either a chemical, manufacturing, or operating origin with a strong correlation between the origins and the type of damage. The chemical defects were either excess ferritic dilution of stellite or excess carburizing. Excess carburizing leads to a too brittle hardfacing which cracks under excessive stresses induced on the seating surfaces, via the stem, by too high operating thrusts. The same conditions can also induce cracks of the seats in the presence, in the hardfacing, of hidden defects generated during the welding process. Reduction of the number of defects results first from controls during manufacturing, mainly in the thickness of stellite. On the other hand, maintenance must be fitted to the type of defect. In-situ lapping may lead to release of cobalt, resulting in contamination of the circuit. Furthermore, it is ineffectual in the case of a crack through the seating surface, as is often found on globe valves. The use of new technologies of valves with removable seats and cobalt-free alloys solves permanently this kind of problem.

  13. Tribological study of hard coatings without cobalt intended to isolation components of PWR primary cooling system; Etude tribologique de revetements durs sans cobalt destines aux organes d`isolement du circuit primaire des REP

    Energy Technology Data Exchange (ETDEWEB)

    Cachon, L.

    1995-10-18

    The objective is to qualify coatings without cobalt to replace ``Stellites`` coatings in isolation valves of PWR primary cooling system, as Co is activated when passing in the reactor core and contaminated the cooling loop. Three families of coatings were tested: PVD thin films from 1 to 8 {mu}m monolayers of Cr/C{sub x} with x varying between 1.6 and 9.5 at% or multilayers of pure chromium and Cr/C{sub 1.6} at%, coatings with a thickness between 100 and 200 {mu}m of cermets NiCr{sub y} (y varying from 5 to 35 at%) matrix binding chromium or tungsten carbides, and thick coatings 2 mm thickness of cermets Nitronic 60 or Inconel 625 matrix binding 10, 20 or 30% titanium or niobium carbides. Stellite 6 (2 mm) is the reference coating for tribology. Coatings were qualified and selected by thermal shocks, corrosion and plane friction. The thin film and the thick families were disqualified by their destruction or by their high friction coefficient. Then coatings between 100 and 200 {mu}m were used in a valve mock-up working in PWR primary cooling system pressure and temperature conditions. Tests show that these coatings have better wear or tightness performances than stellite 6, except for a slightly higher friction coefficient. (A.B.).

  14. Contribution to the replacement of cobalt-free hardfacing coating by laser cladding in fast neutron reactors

    International Nuclear Information System (INIS)

    De-Tran, Van

    2014-01-01

    This thesis contributes to the replacement of the coating of Stellite 6 which is used in friction areas for the primary circuit of the fast neutron reactor. It contains three parts: 1) A literature review for selecting the materials and the deposition process 2) A parametric study to get healthy deposits (good adhesion with the substrate, little porosity, no cracks, low dilution) 3) A study wear behavior of deposits obtained, at high temperature (200 C) under an atmosphere inert gas, to determine the wear resistance of materials selected without the influence of an eventual oxidation layer. From the literature review, it appears the following choices implemented in our study: * the method laser cladding with advantages such as: - Good adhesion (metallurgical) - High cooling speed - Low dilution rate - Wide parametric range * two nickel-based alloys: Colmonoy-52 and Tribaloy-700. These alloys have good dry wear behavior and could be deposited by the laser. In the manufacturing part of the healthy deposit, firstly, we characterized the metal powder. Then, a parametric study was performed to look for a good parametric range that makes us getting a healthy deposit of Stellite 6 (reference) of Colmonoy-52 and Tribaloy-700. In this case, relationships among three main process parameters laser cladding (laser beam power, surface scanning speed, rate of powder) with the microstructure and chemical composition of the deposit are studied. In study the wear behavior, a pin-on-disc type of tribological was used and tests were carried out in argon at room temperature and 200 C. We investigated the wear mechanism of the best deposition of Stellite 6, Colmonoy-52 and Tribaloy-700. The wear resistance of these materials were thoroughly compared. (author) [fr

  15. Aspects of a Co-free hardfacing Materials Development to Reduce the Radioactivity in NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joung Soo; Kim, Hong Pyo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Suh, Jeong Hun [Inss Tek Co., Daejeon (Korea, Republic of)

    2007-07-01

    For the last one or two decades, active researches to develop Co-free hardfacing materials in order to replace Co-base stellite alloys have been done to reduce the radioactivity in the primary systems in nuclear power plants(NPPs). However, Co-free materials having superior mechanical properties to stellite alloys have not been developed up to now. There are two ways to increase the performance characteristics of the key parts needed to be coated with hardfacing materials, thus resulting in replacing the Co-base stellite alloys with superior mechanical properties; one of them is to develop new Co-free materials with a better quality in performance than that of satellite alloys. The other is to use new coating techniques developed to increase the coated surface properties of already developed Co-free materials. In this study, the aspect of newly developed Co-free materials is reviewed and the necessity of the development of new Co-free materials is emphasized for the replacement of Co-base satellite alloys. In addition, a new coating technique, which is called a laser hardfacing(cladding) technique(LHT), is introduced and its advantage and applicability to the key parts in NPPs are discussed using our experimental results to improve the properties of a surface coated with existing Co-free hardfacing materials. The coating technique using a laser beam having a high energy density has unique advantages to obtain various microstructures such as crystalline, amorphous, porous, and nano structures and also to get coating layers having high a hardness to result in an excellent resistance to erosion corrosion and wear.

  16. Deposição por plasma com arco transferido Hardfacing by plasma transfer arc process

    Directory of Open Access Journals (Sweden)

    Víctor Vergara Díaz

    2010-03-01

    Full Text Available Em virtude do Processo de Soldagem Plasma com Alimentação de Pó ter similaridades com o Processo de Soldagem Plasma com Alimentação de Arame, foi realizado um estudo comparativo entre ambos os processos utilizando-se a liga a base de cobalto comercialmente conhecida como Stellite 6, como material de adição na forma de pó e arame. A pesquisa foi realizada com a expectativa de ser aplicada nas operações de revestimentos de superfícies, em especial em pás de turbinas hidráulicas desgastadas por cavitação. A seleção do material de adição a ser empregado depende da natureza do mecanismo de desgaste encontrado. No Labsolda, a liga Stellite 6 vem sendo uma das mais utilizadas, por apresentar uma excelente resistência ao desgaste erosivo por cavitação. Foi avaliada a influência da vazão de gás de plasma a partir dos valores de diluição, dimensões do cordão, dureza e microestrutura. O Processo de Soldagem Plasma com Alimentação de Pó foi o que produziu o melhor acabamento superficial, menor diluição, melhor molhamento e maior largura. Com isto abre-se uma nova perspectiva para revestimentos metálicos e neste contexto se insere a recuperação por soldagem de partes erodidas de turbinas hidráulicas.The Plasma powder transferred arc welding process, which uses feed stock in the powder form, has similarities with Plasma wire transferred arc welding. This work describes a comparative study of the two processes using a Cobalt-based alloy commercially known as Stellite 6. This Co-based alloy is recognized for its superior cavitation erosion resistance. The aim of this work is to investigate the potential of PTA coatings for the protection and refurbishiment hydraulic turbine blades. Coatings were evaluated for the influence of Plasma gas flow rate on coating dilution, geometry, hardness and microstructure. Coatings processed with the atomized Stellite 6 powder feestock showed a superior surface quality, lower dilution

  17. Friction and wear of ball bearings in liquid sodium environment. Pt. 1

    International Nuclear Information System (INIS)

    Kleefeldt, K.; Gering, G.

    1975-07-01

    This report describes sodium experiments with ball bearings, fabricated out of five different materials, i.e. tool steel (s-6-5-2), stainless high speed steel (BG 42), stellite, ferro-titanit (WF 13.5) and tungsten carbide/cobalt cermet (GT 10/20). With each material four cageless bearings of the type 6207 were tested in task 1 under the following test conditions, in order to determine the most promising material for further investigations: test temperature 400 0 C, axial load 300 kp, speed 200 min -1 , total revolutions 0.2 x 10 6 , oxygen concentration [de

  18. Residual stress and crack initiation in laser clad composite layer with Co-based alloy and WC + NiCr

    International Nuclear Information System (INIS)

    Lee, Changmin; Park, Hyungkwon; Yoo, Jaehong; Lee, Changhee; Woo, WanChuck; Park, Sunhong

    2015-01-01

    Highlights: • Major problem, clad cracking in laser cladding process, was researched. • Residual stress measurements were performed quantitatively by neutron diffraction method along the surface of specimens. • Relationship between the residual stress and crack initiation was showed clearly. • Ceramic particle effect in the metal matrix was showed from the results of residual stress measurements. • Initiation sites of generating clad cracks were specifically studied in MMC coatings. - Abstract: Although laser cladding process has been widely used to improve the wear and corrosion resistance, there are unwanted cracking issues during and/or after laser cladding. This study investigates the tendency of Co-based WC + NiCr composite layers to cracking during the laser cladding process. Residual stress distributions of the specimen are measured using neutron diffraction and elucidate the correlation between the residual stress and the cracking in three types of cylindrical specimens; (i) no cladding substrate only, (ii) cladding with 100% stellite#6, and (iii) cladding with 55% stellite#6 and 45% technolase40s. The microstructure of the clad layer was composed of Co-based dendrite and brittle eutectic phases at the dendritic boundaries. And WC particles were distributed on the matrix forming intermediate composition region by partial melting of the surface of particles. The overlaid specimen exhibited tensile residual stress, which was accumulated through the beads due to contraction of the coating layer generated by rapid solidification, while the non-clad specimen showed compressive. Also, the specimen overlaid with 55 wt% stellite#6 and 45 wt% technolase40s showed a tensile stress higher than the specimen overlaid with 100% stellite#6 possibly, due to the difference between thermal expansion coefficients of the matrix and WC particles. Such tensile stresses can be potential driving force to provide an easy crack path ways for large brittle fractures

  19. Residual stress and crack initiation in laser clad composite layer with Co-based alloy and WC + NiCr

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Changmin; Park, Hyungkwon; Yoo, Jaehong [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Changhee, E-mail: chlee@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Woo, WanChuck [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Park, Sunhong [Research Institute of Industrial Science & Technology, Hyo-ja-dong, Po-Hang, Kyoung-buk, San 32 (Korea, Republic of)

    2015-08-01

    Highlights: • Major problem, clad cracking in laser cladding process, was researched. • Residual stress measurements were performed quantitatively by neutron diffraction method along the surface of specimens. • Relationship between the residual stress and crack initiation was showed clearly. • Ceramic particle effect in the metal matrix was showed from the results of residual stress measurements. • Initiation sites of generating clad cracks were specifically studied in MMC coatings. - Abstract: Although laser cladding process has been widely used to improve the wear and corrosion resistance, there are unwanted cracking issues during and/or after laser cladding. This study investigates the tendency of Co-based WC + NiCr composite layers to cracking during the laser cladding process. Residual stress distributions of the specimen are measured using neutron diffraction and elucidate the correlation between the residual stress and the cracking in three types of cylindrical specimens; (i) no cladding substrate only, (ii) cladding with 100% stellite#6, and (iii) cladding with 55% stellite#6 and 45% technolase40s. The microstructure of the clad layer was composed of Co-based dendrite and brittle eutectic phases at the dendritic boundaries. And WC particles were distributed on the matrix forming intermediate composition region by partial melting of the surface of particles. The overlaid specimen exhibited tensile residual stress, which was accumulated through the beads due to contraction of the coating layer generated by rapid solidification, while the non-clad specimen showed compressive. Also, the specimen overlaid with 55 wt% stellite#6 and 45 wt% technolase40s showed a tensile stress higher than the specimen overlaid with 100% stellite#6 possibly, due to the difference between thermal expansion coefficients of the matrix and WC particles. Such tensile stresses can be potential driving force to provide an easy crack path ways for large brittle fractures

  20. Study on Co-free amorphous material cladding using a laser beam to improve the resistance of primary system parts in NPPs to wear/erosion-corrosion

    International Nuclear Information System (INIS)

    Kim, J. S.; Woo, S. S.; Seo, J. H.

    2001-01-01

    A study on Co-free amorphous material, ARMACOR M, cladding using a laser beam has been performed to improve resistance of the primary system main parts on nuclear power plants to wear/erosion-corrosion. The wear/erosion-corrosion properties of ARMACRO M cladded speciemens were characterized in air at room temperature and 300 .deg. C and in air at room temperature, and compared to those of other hardfacing materials, such as Stellite 6, NOREM 02, Deloro 50, TIG-welde or laer cladded. According to the results, ARMACOR M laser-cladded specimen showed to have the highest resistance to wear/erosion-corrosion

  1. RA Reactor operation and maintenance (I-IX), part V, Task 3.08/04-06, Refurbishment of the heavy water pumps

    International Nuclear Information System (INIS)

    Zecevic, V.; Nikolic, M.; Milic, J.

    1963-12-01

    In addition to detailed instructions for maintenance and repair of the heavy water pumps at the RA reactor this document includes nine annexes. They are as follows: cleaning the heavy water pump Avala with distilled water; instructions for repair of the pump CEN-132 (two annexes); list of operating characteristics of the pumps before repair; conclusions of the experts concerning the worn out bearings of the heavy water pump Avala, with the analysis of the stellite layer; report on the completed repair actions on the pumps Avala and CEN-132; report on the measurements done on the pump Avala; and the certificate concerning inspection of the pump

  2. RA Reactor operation and maintenance (I-IX), part V, Task 3.08/04-06, Refurbishment of the heavy water pumps; Pogon i odrzavanje reaktora RA (I-IX), V Deo, Zadatak 3.08/04-06 Remont teskovodnih pumpi

    Energy Technology Data Exchange (ETDEWEB)

    Zecevic, V; Nikolic, M; Milic, J [Institute of Nuclear Sciences Boris Kidric, Reaktor RA, Vinca, Beograd (Serbia and Montenegro)

    1963-12-15

    In addition to detailed instructions for maintenance and repair of the heavy water pumps at the RA reactor this document includes nine annexes. They are as follows: cleaning the heavy water pump Avala with distilled water; instructions for repair of the pump CEN-132 (two annexes); list of operating characteristics of the pumps before repair; conclusions of the experts concerning the worn out bearings of the heavy water pump Avala, with the analysis of the stellite layer; report on the completed repair actions on the pumps Avala and CEN-132; report on the measurements done on the pump Avala; and the certificate concerning inspection of the pump.

  3. Physical properties and microstructure performance of ultrafine nanocrystals reinforced laser 3D print microlaminates

    International Nuclear Information System (INIS)

    Li, Jianing; Xia, Chunzhi; Liu, Peng; Pan, Guanghui; Wang, Congwei

    2015-01-01

    Highlights: • Ultrafine nanocrystals, nanorods and amorphous phases were produced in such LRP microlaminates. • The amorphous/nanocrystalline interface owned a high bonding energy. • Amorphous/nanocrystalline interface may retard growth of nanocrystals in a certain extent. • Due to production of amorphous, lots of microscale ASNPs were produced. • Ultrafine nanocrystals had the high interface energy, which became the driving force of the atomic motions. - Abstract: Rapid prototyping based on laser alloying was used to produce ultrafine nanocrystals (UN) reinforced three-dimensional microlaminates. Such microlaminates were fabricated on a TA1 alloy by laser rapid prototyping (LRP) of Stellite 20–TiN–B 4 C mixed powders to produce a bottom layer; then Stellite 20–TiN–B 4 C–Sb powders were deposited on such bottom-layer in order to form an upper-layer. There is an excellent metallurgical combination between such two layer; the upper-layer shows a better wear resistance than that of the bottom layer. The Sb addition promoted lots of UN to be produced, and lots of the nanorods were also produced in such microlaminates, their growth was retarded by agglomeration of UN in a certain extent. Such UN had the high interface energy, which became the driving force of atomic motions, favoring formation of a compact fine structure

  4. High power CO2 lasers and their applications in nuclear industry

    International Nuclear Information System (INIS)

    Nath, A.K.

    2002-01-01

    Carbon dioxide laser is one of the most popular lasers in industry for material processing applications. It has very high power capability and high efficiency, can be operated in continuous wave (CW), modulated and pulsed modes, and has relatively low cost. Due to these characteristics high power CO 2 lasers are being used worldwide in different industries for a wide variety of materials processing operations. In nuclear industry, CO 2 laser has made its way in many applications. Some of the tasks performed by multikilowatt CO 2 laser are cutting operations necessary to remove unprocessible hardware from reactor fuel assemblies, sealing/fixing/removing radioactive contaminations onto/from concrete surfaces and surface modification of engineering components for improved surface mechanical and metallurgical characteristics. We have developed various models of CW CO 2 lasers of power up to 12 kW and a high repetitive rate TEA (Transversely Excited Atmospheric pressure) CO 2 laser of 500 W average power operating at 500 Hz repetition rates. We have carried many materials processing applications of direct relevance to DAE. Recent work includes laser welding of end plug PFBR fuel tubes, martensitic stainless steel and titanium alloy, surface cladding of turbine blades made of Ni-super alloy with stellite 694, fabrication on graded material of stainless steel and stellite, and laser scabbling, drilling and cutting of concrete which have potential application in decontamination and decommissioning of nuclear facilities. A brief overview of these indigenous developments will be presented. (author)

  5. Modeling the Influence of Process Parameters and Additional Heat Sources on Residual Stresses in Laser Cladding

    Science.gov (United States)

    Brückner, F.; Lepski, D.; Beyer, E.

    2007-09-01

    In laser cladding thermal contraction of the initially liquid coating during cooling causes residual stresses and possibly cracks. Preweld or postweld heating using inductors can reduce the thermal strain difference between coating and substrate and thus reduce the resulting stress. The aim of this work is to better understand the influence of various thermometallurgical and mechanical phenomena on stress evolution and to optimize the induction-assisted laser cladding process to get crack-free coatings of hard materials at high feed rates. First, an analytical one-dimensional model is used to visualize the most important features of stress evolution for a Stellite coating on a steel substrate. For more accurate studies, laser cladding is simulated including the powder-beam interaction, the powder catchment by the melt pool, and the self-consistent calculation of temperature field and bead shape. A three-dimensional finite element model and the required equivalent heat sources are derived from the results and used for the transient thermomechanical analysis, taking into account phase transformations and the elastic-plastic material behavior with strain hardening. Results are presented for the influence of process parameters such as feed rate, heat input, and inductor size on the residual stresses at a single bead of Stellite coatings on steel.

  6. Physical properties and microstructure performance of ultrafine nanocrystals reinforced laser 3D print microlaminates

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianing, E-mail: jn2369@163.com [School of Materials Science and Engineering, Shandong Jianzhu University, Jinan 250101 (China); Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024 (China); Xia, Chunzhi [Provincial Laboratory of Advanced Welding Technology, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Liu, Peng; Pan, Guanghui; Wang, Congwei [School of Materials Science and Engineering, Shandong Jianzhu University, Jinan 250101 (China)

    2015-10-05

    Highlights: • Ultrafine nanocrystals, nanorods and amorphous phases were produced in such LRP microlaminates. • The amorphous/nanocrystalline interface owned a high bonding energy. • Amorphous/nanocrystalline interface may retard growth of nanocrystals in a certain extent. • Due to production of amorphous, lots of microscale ASNPs were produced. • Ultrafine nanocrystals had the high interface energy, which became the driving force of the atomic motions. - Abstract: Rapid prototyping based on laser alloying was used to produce ultrafine nanocrystals (UN) reinforced three-dimensional microlaminates. Such microlaminates were fabricated on a TA1 alloy by laser rapid prototyping (LRP) of Stellite 20–TiN–B{sub 4}C mixed powders to produce a bottom layer; then Stellite 20–TiN–B{sub 4}C–Sb powders were deposited on such bottom-layer in order to form an upper-layer. There is an excellent metallurgical combination between such two layer; the upper-layer shows a better wear resistance than that of the bottom layer. The Sb addition promoted lots of UN to be produced, and lots of the nanorods were also produced in such microlaminates, their growth was retarded by agglomeration of UN in a certain extent. Such UN had the high interface energy, which became the driving force of atomic motions, favoring formation of a compact fine structure.

  7. APPLICATION OF QC TOOLS FOR CONTINUOUS IMPROVEMENT IN AN EXPENSIVE SEAT HARDFACING PROCESS USING TIG WELDING

    Directory of Open Access Journals (Sweden)

    Mohammed Yunus

    2016-09-01

    Full Text Available The present study is carried out to improve quality level by identifying the prime reasons of the quality related problems in the seat hardfacing process involving the deposition of cobalt based super alloy in I.C. Engine valves using TIG welding process. During the Process, defects like stellite deposition overflow, head melt, non-uniform stellite merging, etc., are observed and combining all these defects, the rejection level was in top position in Forge shop. We use widely referred QC tools of the manufacturing field to monitor the complete operation and continuous progressive process improvement to ensure ability and efficiency of quality management system of any firm. The work aims to identify the various causes for the rejection by the detailed study of the operation, equipment, materials and the various process parameters that are very important to get defects-free products. Also, to evolve suitable countermeasures for reducing the rejection percentage using seven QC tools. To further understand and validate the obtained results, we need to address other studies related to motivations, advantages, and disadvantages of applying quality control tools.

  8. Replacement of Co-base alloy for radiation exposure reduction in the primary system of PWR

    International Nuclear Information System (INIS)

    Han, Jeong Ho; Nyo, Kye Ho; Lee, Deok Hyun; Lim, Deok Jae; Ahn, Jin Keun; Kim, Sun Jin

    1996-01-01

    Of numerous Co-free alloys developed to replace Co-base stellite used in valve hardfacing material, two iron-base alloys of Armacor M and Tristelle 5183 and one nickel-base alloy of Nucalloy 488 were selected as candidate Co-free alloys, and Stellite 6 was also selected as a standard hardfacing material. These four alloys were welded on 316SS substrate using TIG welding method. The first corrosion test loop of KAERI simulating the water chemistry and operation condition of the primary system of PWR was designed and fabricated. Corrosion behaviors of the above four kinds of alloys were evaluated using this test loop under the condition of 300 deg C, 1500 psi. Microstructures of weldment of these alloys were observed to identify both matrix and secondary phase in each weldment. Hardnesses of weld deposit layer including HAZ and substrate were measured using micro-Vickers hardness tester. The status on the technology of Co-base alloy replacement in valve components was reviewed with respect to the classification of valves to be replaced, the development of Co-free alloys, the application of Co-free alloys and its experiences in foreign NPPs, and the Co reduction program in domestic NPPs and industries. 18 tabs., 20 figs., 22 refs. (Author)

  9. Liquid impact erosion mechanism and theoretical impact stress analysis in TiN-coated steam turbine blade materials

    International Nuclear Information System (INIS)

    Lee, M.K.; Kim, W.W.; Rhee, C.K.; Lee, W.J.

    1999-01-01

    Coating of TiN film was done by reactive magnetron sputter ion plating to improve the liquid impact erosion resistance of steam turbine blade materials, 12Cr steel and Stellite 6B, for nuclear power plant application. TiN-coated blade materials were initially deformed with depressions due to plastic deformation of the ductile substrate. The increase in the curvature in the depressions induced stress concentration with increasing number of impacts, followed by circumferential fracture of the TiN coating due to the circular propagation of cracks. The liquid impact erosion resistance of the blade materials was greatly improved by TiN coating done with the optimum ion plating condition. Damage decreased with increasing TiN coating thickness. According to the theoretical analysis of stresses generated by liquid impact, TiN coating alleviated the impact stress of 12Cr steel and Stellite 6B due to stress attenuation and stress wave reactions such as reflection and transmission at the coating-substrate interface

  10. Liquid Impact Erosion Mechanism and Theoretical Stress Analysis in TiN-Coated Turbine Blade

    International Nuclear Information System (INIS)

    Lee, M. K.; Kim, W. W.; Kim, S. J.; Rhee, C. K.; Kim, Y. S.

    2000-01-01

    Coating of TiN film was done by reactive magnetron sputter ion plating to improve the liquid impact erosion resistance of steam turbine blade materials, 12Cr steel and Stellite 6B, for nuclear power plant application. TiN coated blade materials were initially deformed with depressions due to plastic deformation of the ductile substrate. The increase in the curvature in the depressions induced stress concentration with increasing number of impacts, followed by circumferential fracture of the TiN coating due to the circular propagation of cracks. The liquid impact erosion resistance of the blade materials was greatly improved by TiN coating done with the optimum ion plating condition. Damage decreased with increasing TiN coating thickness. According to the theoretical analysis of stresses generated by liquid impact, TiN coating alleviated the impact stress of 12Cr steel and Stellite 6B due to stress attenuation and stress wave reactions such as reflection and transmission at the coating substrate interface

  11. Laser stereolithography by multilayer cladding of metal powders

    Science.gov (United States)

    Jendrzejewski, Rafal; Rabczuk, Grazyna T.; Zaremba, R.; Sliwinski, Gerard

    1998-07-01

    3D-structures obtained by means of laser cladding of the metal alloy powders: bronze B10 and stellite 6 and the process parameters are studied experimentally. The structures are made trace-on-trace by remelting of the metal powder injected into the focusing region of the 1.2 kW CO2 laser beam. For the powder and sample feeding rates of 8-22 g/min and 0.4-1.2 m/min, respectively, and the applied beam intensities not exceeding 2 X 105 W cm-2 the process is stable and regular traces connected via fusion zones are produced for each material. The thickness of these zones does not exceed several per cent of the layer height. The process results in the efficient formation of multilayer structures. From their geometry the effect of energy coupling and interaction parameters are deduced. Moreover, the microanalysis by means of SEM- and optical photographs of samples produced under different experimental conditions confirms the expected mechanical properties, low porosity and highly homogenous structure of the multilayers. In addition to the known material stellite 6 the bronze B10 is originally proposed for a rapid prototyping.

  12. Heavy water pumps; Pumpe D{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Zecevic, V; Nikolic, M

    1963-12-15

    Continuous increase of radiation intensity was observed on all the elements in the heavy water system during first three years of RA reactor operation. The analysis of heavy water has shown the existence of radioactive cobalt. It was found that cobalt comes from stellite, cobalt based alloy which was used for coating of the heavy water pump discs in order to increase resistance to wearing. Cobalt was removed from the surfaces due to friction, and transferred by heavy water into the reactor where it has been irradiated for 29 876 MWh up to 8-15 Ci/g. Radioactive cobalt contaminated all the surfaces of aluminium and stainless steel parts. This report includes detailed description of heavy water pumps repair, exchange of stellite coated parts, decontamination of the heavy water system, distillation of heavy water. [Serbo-Croat] U toku prve tri godine eksploatacije reaktora RA uocen je neprekidni porast intenziteta zracenja na svim elementima u teskovodnom sistemu. Analizom teske vode utvrdjeno je postojanje radioaktivnog kobalta. Ustanovljeno je da kobalt potice od stelita, legure na bazi kobalta kojim su presvuceni rukavci vratila teskovodnih pumpi radi otpornosi na habanje. Kobalt je trenjem skidan sa povrsina, u toku rada prenosen je teskom vodom u reaktor i ozracivan u toku 29 876 MWh do specificne aktivnosti 8-15 Ci/g. Radioaktivni kobalt je kontaminirao sve povrsine od aluminijuma i nerdjajuceg celika. Ovaj izvestaj sadrzi detaljan opis remonta pumpi, zamene delova teskovodnih pumpi novim delovima bez stelitnog sloja, dekontaminacije teskovodnog sistema, destilacije teske vode.

  13. ALARA efforts in nordic BWRs

    Energy Technology Data Exchange (ETDEWEB)

    Ingemansson, T.; Lundgren, K.; Elkert, J. [ABB Atom, Vaesteraes (Sweden)

    1995-03-01

    Some ALARA-related ABB Atom projects are currently under investigation. One of the projects has been ordered by the Swedish Radiation Protection Institute, and two others by the Nordic BWR utilities. The ultimate objective of the projects is to identify and develop methods to significantly decrease the future exposure levels in the Nordic BWRS. As 85% to 90% of the gamma radiation field in the Nordic BWRs originates from Co-60, the only way to significantly decrease the radiation doses is to effect Co and Co-60. The strategy to do this is to map the Co sources and estimate the source strength of Co from these sources, and to study the possibility to affect the release of Co-60 from the core surfaces and the uptake on system surfaces. Preliminary results indicate that corrosion/erosion of a relatively small number of Stellite-coated valves and/or dust from grinding of Stellite valves may significantly contribute to the Co input to the reactors. This can be seen from a high measured Co/Ni ratio in the feedwater and in the reactor water. If stainless steel is the only source of Co, the Co/Ni ratio would be less than 0.02 as the Co content in the steel is less than 0.2%. The Co/Ni ratio in the reactor water, however, is higher than 0.1, indicating that the major fraction of the Co originates from Stellite-coated valves. There are also other possible explanations for an increase of the radiation fields. The Co-60 inventory on the core surfaces increases approximately as the square of the burn-up level. If the burn-up is increased from 35 to 5 MWd/kgU, the Co-60 inventory on the core surfaces will be doubled. Also the effect on the behavior of Co-60 of different water chemistry and materials conditions is being investigated. Examples of areas studied are Fe and Zn injection, pH-control, and different forms of surface pre-treatments.

  14. Relationship of microstructure to fracture topography in orthopedic alloys

    International Nuclear Information System (INIS)

    Gilbertson, L.N.

    1976-01-01

    Two major alloys used for orthopedic implants are 316L stainless steel and a cast cobalt--chromium--molybdenum alloy similar to Haynes Stellite 21. Another alloy that is just being introduced is Ti--6Al--4V. All three of these alloys are used in different conditions with different microstructures. Standard specimens with typical microstructures encountered in orthopedic applications were loaded to fracture in both overload and fatigue modes. Different rates of loading were also used in some cases. The fracture surfaces of these standard samples were analyzed in the Scanning Electron Microscope. An attempt was made to relate the fracture behavior, as evidenced by the fracture typography, to the microstructure of the alloy as revealed by metallography

  15. Synthesis Of NiCrAlC alloys by mechanical alloying

    International Nuclear Information System (INIS)

    Silva, A.K.; Pereira, J.I.; Vurobi Junior, S.; Cintho, O.M.

    2010-01-01

    The purpose of the present paper is the synthesis of nickel alloys (NiCrAlC), which has been proposed like a economic alternative to the Stellite family Co alloys using mechanical alloying, followed by sintering heat treatment of milled material. The NiCrAlC alloys consist of a chromium carbides dispersion in a Ni 3 Al intermetallic matrix, that is easily synthesized by mechanical alloying. The use of mechanical alloying enables higher carbides sizes and distribution control in the matrix during sintering. We are also investigated the compaction of the processed materials by compressibility curves. The milling products were characterized by X-ray diffraction, and the end product was featured by conventional metallography and scanning electronic microscopy (SEM), that enabled the identification of desired phases, beyond microhardness test, which has been shown comparable to alloys manufactured by fusion after heat treating. (author)

  16. Absorptivity Measurements and Heat Source Modeling to Simulate Laser Cladding

    Science.gov (United States)

    Wirth, Florian; Eisenbarth, Daniel; Wegener, Konrad

    The laser cladding process gains importance, as it does not only allow the application of surface coatings, but also additive manufacturing of three-dimensional parts. In both cases, process simulation can contribute to process optimization. Heat source modeling is one of the main issues for an accurate model and simulation of the laser cladding process. While the laser beam intensity distribution is readily known, the other two main effects on the process' heat input are non-trivial. Namely the measurement of the absorptivity of the applied materials as well as the powder attenuation. Therefore, calorimetry measurements were carried out. The measurement method and the measurement results for laser cladding of Stellite 6 on structural steel S 235 and for the processing of Inconel 625 are presented both using a CO2 laser as well as a high power diode laser (HPDL). Additionally, a heat source model is deduced.

  17. Cobalt-60 control in Ontario Hydro reactors

    International Nuclear Information System (INIS)

    Lacy, C.S.

    1988-01-01

    This paper discusses the impact of specifying reduced Cobalt-59 in the primary heat transport circuit materials of construction on the radiation fields developed around the primary circuit. An eight-fold reduction in steam generator radiation fields due to Cobalt-60 has been observed for two identical sets of reactors, one with and one without Cobalt-59 control. The comparison is between eight reactors at the Pickering Nuclear Generating Station (PNGS). Units 5 to 8 (PNGS-B) are identical to Units 1 to 4 (PNGS-A) except that PNGS-B has reduced impurity Cobalt-59 in the alloys of construction and a reduced use of stellite. The effects of chemistry control are also discussed

  18. Test methods for selection of materials of construction for high-level radioactive waste vitrification. Revision

    International Nuclear Information System (INIS)

    Bickford, D.F.; Corbett, R.A.; Morrison, W.S.

    1986-01-01

    Candidate materials of construction were evaluated for a facility at the Department of Energy's Savannah River Plant to vitrify high-level radioactive waste. Limited operating experience was available under the corrosive conditions of the complex vitrification process. The objective of the testing program was to provide a high degree of assurance that equipment will meet or exceed design lifetimes. To meet this objective in reasonable time and minimum cost, a program was designed consisting of a combination of coupon immersion and electrochemical laboratory tests and pilot-scale tests. Stainless steels and nickel-based alloys were tested. Alloys that were most resistant to general and local attack contained nickel, molybdenum (>9%), and chromium (where Cr + Mo > 30%). Alloy C-276 was selected as the reference material for process equipment. Stellite 6 was selected for abrasive service in the presence of formic acid. Alloy 690 and ALLCORR were selected for specific applications

  19. Synthesis Of NiCrAlC alloys by mechanical alloying; Sintese de ligas NiCrAlC por moagem de alta energia

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.K.; Pereira, J.I.; Vurobi Junior, S.; Cintho, O.M., E-mail: alissonkws@gmail.co [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil)

    2010-07-01

    The purpose of the present paper is the synthesis of nickel alloys (NiCrAlC), which has been proposed like a economic alternative to the Stellite family Co alloys using mechanical alloying, followed by sintering heat treatment of milled material. The NiCrAlC alloys consist of a chromium carbides dispersion in a Ni{sub 3}Al intermetallic matrix, that is easily synthesized by mechanical alloying. The use of mechanical alloying enables higher carbides sizes and distribution control in the matrix during sintering. We are also investigated the compaction of the processed materials by compressibility curves. The milling products were characterized by X-ray diffraction, and the end product was featured by conventional metallography and scanning electronic microscopy (SEM), that enabled the identification of desired phases, beyond microhardness test, which has been shown comparable to alloys manufactured by fusion after heat treating. (author)

  20. Recent experience about the influence of primary coolant and shutdown chemistry on cobalt activity at Beznau NPP

    International Nuclear Information System (INIS)

    Mailand, I.; Venz, H.

    2007-01-01

    The Beznau nuclear power plant comprises two identical 380 MWe PWR units, commissioned in 1969 and 1971. The surfaces of the new steam generator tube material, Inconel 690, are the main source of 58 Co. The 60 Co originates predominantly from the Cobalt alloy, Stellite, which is installed in valves and pump bearings because of the very good hardness of this material. By means of optimised shutdown chemistry it is possible to reduce the amount of NiO on the fuel rods, leading to reduced Co-58 peaks in subsequent cycles. The optimised shutdown chemistry during the past few years and especially the strict separation of acid-reducing phase from the acid-oxidising phase as well as the results of studies and the resulting operational experiences are important basics for the actual operation mode of the Beznau NPP. (orig.)

  1. Laser fabrication nanocrystalline coatings using simultaneous powders/wire feed

    Science.gov (United States)

    Li, Jianing; Zhai, Tongguang; Zhang, Yuanbin; Shan, Feihu; Liu, Peng; Ren, Guocheng

    2016-07-01

    Laser melting deposition (LMD) fabrication is used to investigate feasibilty of simultaneously feeding TC17 wire and the Stellite 20-Si3N4-TiC-Sb mixed powders in order to increase the utilization ratio of materials and also quality of LMD composite coatings on the TA1 substrate. SEM images indicated that such LMD coating with metallurgical joint to substrate was formed free of the obvious defects. Lots of the ultrafine nanocrystals (UNs) were produced, which distributed uniformly in some coating matrix location, retarding growth of the ceramics in a certain extent; UNs were intertwined with amorphous, leading the yarn-shape materials to be produced. Compared with substrate, an improvement of wear resistance was achieved for such LMD coating.

  2. Conclusion of the commission for determining wear out of Avala heavy water pump bearings - Annex 1; Prilog1 - Zakljucak komisije za utvrdjivanje istrosenosti lezista teskovodne pumpe Avala

    Energy Technology Data Exchange (ETDEWEB)

    Nikolic, M; Bratic, A; Zaric, Z; Vidmar, M; Kirilin, J [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1963-12-15

    After dismantling of the CEN-132 pump the findings of the Commission were: the wear-out of the surfaces of the pump bearings and one disc caused appearance of about 39 grams of cobalt in the heavy water system of the reactor. This report includes: results of chemical analysis of stellite taken form pump disc, results of measuring the wear-out of the upper pump bearing, drawing of the worn-out disc and upper cladding of the pump, and a photo of the upper surface of the disc. [Serbo-Croat] Posle demontaze pumpe CEN-132, pregleda detalja i izvrsenih merenja komisija je konstatovala da je zbog istrosenosti lezista diska pumpe i istrosenosti gornje caure u teskovodni sistem dospelo ukupno 39 grama kobalta. Ovaj dokument sadrzi i rezultate hemijske analize stelita skinutog sa diska pumpe, rezultate merenja istrosenosti gornjeg lezista teskovodne pumpe, crteze istrosnog diska skinutog sa pumpe, crteze gornje caure, fotografiju gornje povrsine diska.

  3. Cladding using a 15 kW CO2 laser

    International Nuclear Information System (INIS)

    Vesely, E.J.; Verma, S.K.

    1989-01-01

    Laser alloying or cladding differs little in principle from the traditional forms of weld overlays, but lasers as a heat source offer some distinct advantages. With the selective heating attainable using high power lasers, good metallurgical bond of the clad layer, minimal dilution and typically, a very fine homogeneous microstructure can be obtained in the clad layer. This is a review of work in laser cladding using the 15 kW CO 2 laser. The authors discuss the ability of the laser clad surface to increase the high temperature oxidation resistance of a low-alloy carbon steel (4140). Examples of clads subjected to high- temperature thermal cycling of nickel-20% aluminum and TaC + 4140 clad low-alloy steel and straight high-temperature oxidation of Stellite 6-304L cladding on a 4140 substrate are given

  4. Experimental evaluation of the wear of the PEC type fuel element base. Tribological experimental studies in Na at high temperature

    International Nuclear Information System (INIS)

    D'Agraives, B.C.; Volcan, A.; Bacchilega, A.

    1978-01-01

    Tribological studies in sodium, related to the PEC-type fuel element design are presented. They are aimed at the simulation of friction and wear phenomena which are expected to occur on the surface of fuel element components undergoing solid-solid contact situations with variable loads and/or variable motions. In this first paper, a description of the preparatory work is given. Then, results related to long-duration experiments are shown with respect to the contact between the centering spherical ring belonging to the lower extension of the subassembly, and the cylindrical sleeve of the grid in which it takes place. After 1000 hours under loaded and vibrated conditions, in sodium at 400 0 C, the wear effects suffered by both contacting samples, are observed and evaluated. The stellite surfaces of the samples are damaged to a not-negligible extent and material transfers from the cylindrical sleeve onto the spherical ring occur

  5. Reactive Fabrication and Effect of NbC on Microstructure and Tribological Properties of CrS Co-Based Self-Lubricating Coatings by Laser Cladding.

    Science.gov (United States)

    Fang, Liuyang; Yan, Hua; Yao, Yansong; Zhang, Peilei; Gao, Qiushi; Qin, Yang

    2017-12-28

    The CrS/NbC Co-based self-lubricating composite coatings were successfully fabricated on Cr12MoV steel surface by laser clad Stellite 6, WS₂, and NbC mixed powders. The phase composition, microstructure, and tribological properties of the coatings ware investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS), as well as dry sliding wear testing. Based on the experimental results, it was found reactions between WS₂ and Co-based alloy powder had occurred, which generated solid-lubricant phase CrS, and NbC play a key role in improving CrS nuclear and refining microstructure of Co-based composite coating during laser cladding processing. The coatings were mainly composed of γ-Co, CrS, NbC, Cr 23 C₆, and CoC x . Due to the distribution of the relatively hard phase of NbC and the solid lubricating phase CrS, the coatings had better wear resistance. Moreover, the suitable balance of CrS and NbC was favorable for further decreasing the friction and improving the stability of the contact surfaces between the WC ball and the coatings. The microhardness, friction coefficient, and wear rate of the coating 4 (Clad powders composed of 60 wt % Stellite 6, 30 wt % NbC and 10 wt % WS₂) were 587.3 HV 0.5 , 0.426, and 5.61 × 10 -5 mm³/N·m, respectively.

  6. Reactive Fabrication and Effect of NbC on Microstructure and Tribological Properties of CrS Co-Based Self-Lubricating Coatings by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Liuyang Fang

    2017-12-01

    Full Text Available The CrS/NbC Co-based self-lubricating composite coatings were successfully fabricated on Cr12MoV steel surface by laser clad Stellite 6, WS2, and NbC mixed powders. The phase composition, microstructure, and tribological properties of the coatings ware investigated by means of X-ray diffraction (XRD, scanning electron microscopy (SEM, and energy dispersive spectrometer (EDS, as well as dry sliding wear testing. Based on the experimental results, it was found reactions between WS2 and Co-based alloy powder had occurred, which generated solid-lubricant phase CrS, and NbC play a key role in improving CrS nuclear and refining microstructure of Co-based composite coating during laser cladding processing. The coatings were mainly composed of γ-Co, CrS, NbC, Cr23C6, and CoCx. Due to the distribution of the relatively hard phase of NbC and the solid lubricating phase CrS, the coatings had better wear resistance. Moreover, the suitable balance of CrS and NbC was favorable for further decreasing the friction and improving the stability of the contact surfaces between the WC ball and the coatings. The microhardness, friction coefficient, and wear rate of the coating 4 (Clad powders composed of 60 wt % Stellite 6, 30 wt % NbC and 10 wt % WS2 were 587.3 HV0.5, 0.426, and 5.61 × 10−5 mm3/N·m, respectively.

  7. Modelling of residual stresses in valves Norem hard-facing alloys: a material characterization issue

    International Nuclear Information System (INIS)

    Mathieu, J.P.; Arnoldi, F.; Gauthier, E.; Beaurin, G.

    2011-01-01

    Replacement of cobalt-based hard-facing alloys (Stellite) is of high interest within the topic of reduction of human radiation exposure during field-work. Iron-based hard-facing alloys, such as Norem, are considered as good replacement candidates. Their wear characteristics are known to be quite equivalent to Stellite but are counter-balanced by lack of feedback in the field, especially about their resistance/toughness to brutal thermal shocks (60 C - 280 C for primary water). Norem alloys show a solid-solution strengthened austenitic dendrites matrix with a continuous network of eutectic and non-eutectic carbides at the grain boundaries. Toughness evaluation also requires information about residual stresses due to the welding (deposition) process: this work aims at furnishing tools for this purpose. First part of the work involved a microstructural study in order to compare the as-received material to other Norem samples previously observed in EDF's works and literature. A characterization of the different phase evolutions after heating and fast cooling of Norem is then made, in order to characterize whether metallurgical aspects have to be considered in the mechanical part during welding modelling: it appears that no strong solid-solid phase transformation may occur in welding situation. Tensile characterization is then performed on bulk PTAW (Plasma Transferred Arc Welding) specimens. A simplified welding simulation is eventually conducted on different axis-symmetric geometry and on real valve geometry in order to define a representative sample that will be used for further investigation on residual stresses. (authors)

  8. Development of high-power CO2 lasers and laser material processing

    Science.gov (United States)

    Nath, Ashish K.; Choudhary, Praveen; Kumar, Manoj; Kaul, R.

    2000-02-01

    Scaling laws to determine the physical dimensions of the active medium and optical resonator parameters for designing convective cooled CO2 lasers have been established. High power CW CO2 lasers upto 5 kW output power and a high repetition rate TEA CO2 laser of 500 Hz and 500 W average power incorporated with a novel scheme for uniform UV pre- ionization have been developed for material processing applications. Technical viability of laser processing of several engineering components, for example laser surface hardening of fine teeth of files, laser welding of martensitic steel shroud and titanium alloy under-strap of turbine, laser cladding of Ni super-alloy with stellite for refurbishing turbine blades were established using these lasers. Laser alloying of pre-placed SiC coating on different types of aluminum alloy, commercially pure titanium and Ti-6Al-4V alloy, and laser curing of thermosetting powder coating have been also studied. Development of these lasers and results of some of the processing studies are briefly presented here.

  9. Production and Characterization of WC-Reinforced Co-Based Superalloy Matrix Composites

    Science.gov (United States)

    Özgün, Özgür; Dinler, İlyas

    2018-05-01

    Cobalt-based superalloy matrix composite materials were produced through the powder metallurgy technique using element powders at high purity and nano-sized wolfram carbide (WC) reinforcement in this study. An alloy that had the same chemical composition as the Stellite 6 alloy but not containing carbon was selected as the matrix alloy. The powder mixtures obtained as a result of mixing WC reinforcing member and element powders at the determined ratio were shaped by applying 300 MPa of pressure. The green components were sintered under argon atmosphere at 1240 °C for 120 minutes. The densities of the sintered components were determined by the Archimedes' principle. Microstructural characterization was performed via X-ray diffraction analysis, scanning electron microscope examinations, and energy-dispersive spectrometry. Hardness measurements and tensile tests were performed for determining mechanical characteristics. The relative density values of the sintered components increased by increasing the WC reinforcement ratio and they could almost reach the theoretical density. It was determined from the microstructural examinations that the composite materials consisted of fine and equiaxed grains and coarse carbides demonstrating a homogeneous dispersion along the microstructure at the grain boundaries. As it was the case in the density values, the hardness and strength values of the composites increased by increasing the WC ratio.

  10. Stem thrust prediction model for W-K-M double wedge parallel expanding gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Eldiwany, B.; Alvarez, P.D. [Kalsi Engineering Inc., Sugar Land, TX (United States); Wolfe, K. [Electric Power Research Institute, Palo Alto, CA (United States)

    1996-12-01

    An analytical model for determining the required valve stem thrust during opening and closing strokes of W-K-M parallel expanding gate valves was developed as part of the EPRI Motor-Operated Valve Performance Prediction Methodology (EPRI MOV PPM) Program. The model was validated against measured stem thrust data obtained from in-situ testing of three W-K-M valves. Model predictions show favorable, bounding agreement with the measured data for valves with Stellite 6 hardfacing on the disks and seat rings for water flow in the preferred flow direction (gate downstream). The maximum required thrust to open and to close the valve (excluding wedging and unwedging forces) occurs at a slightly open position and not at the fully closed position. In the nonpreferred flow direction, the model shows that premature wedging can occur during {Delta}P closure strokes even when the coefficients of friction at different sliding surfaces are within the typical range. This paper summarizes the model description and comparison against test data.

  11. Microanalysis of tool steel and glass with laser-induced breakdown spectroscopy

    Science.gov (United States)

    Loebe, Klaus; Uhl, Arnold; Lucht, Hartmut

    2003-10-01

    A laser microscope system for the microanalytical characterization of complex materials is described. The universal measuring principle of laser-induced breakdown spectroscopy (LIBS) in combination with echelle optics permits a fast simultaneous multielement analysis with a possible spatial resolution below 10 pm. The developed system features completely UV-transparent optics for the laser-microscope coupling and the emission beam path and enables parallel signal detection within the wavelength range of 200-800 nm with a spectral resolution of a few picometers. Investigations of glass defects and tool steels were performed. The characterization of a glass defect in a tumbler by a micro-LIBS line scan, with use of a 266-nm diode-pumped Nd:YAG laser for excitation, is possible by simple comparison of plasma spectra of the defect and the surrounding area. Variations in the main elemental composition as well as impurities by trace elements are detected at the same time. Through measurement of the calibration samples with the known concentration of the corresponding element, a correlation between the intensity of spectral lines and the element concentration was also achieved. The change of elemental composition at the transient stellite solder of tool steels has been determined by an area scan. The two-dimensional pictures show abrupt changes of the element distribution along the solder edge and allow fundamental researches of dynamic modifications (e.g., diffusion) in steel.

  12. Radiation buildup and control in BWR recirculation piping

    International Nuclear Information System (INIS)

    Meyer, W.; Wood, R.M.; Rao, T.V.; Vook, R.W.

    1987-01-01

    Boiling water nuclear reactors (BWRs) employ stainless steel (Types 304 or 316 NG) pipes in which high-purity water at temperatures of ∼ 275 0 C are circulated. Various components of the system, such as valves and bearings, often contain hard facing metal alloys such as Stellite-6. These components, along with the stainless steel tubing and feedwater, serve as sources of 59 Co. This cobalt, along with other soluble and insoluble impurities, is carried along with the circulating water to the reactor core where it is converted to radioactive 60 Co. After reentering the circulating water, the 60 Co can be incorporated into a complex corrosion layer in the form of CoCr 2 O 4 and/or CoFe 2 O 4 . The presence of even small amounts of 60 Co on the walls of BWR cooling systems is the dominant contributor to inplant radiation levels. Thus BWR owners and their agents are expending significant time and resources in efforts to reduce both the rate and amount of 60 Co buildup. The object of this research is twofold: (a) to form a thin diffusion barrier against the outward migration of cobalt from a cobalt-containing surface and (b) to prevent the growth of a 60 Co-containing corrosion film. The latter goal was the more important since most of the radioactive cobalt will originate from sources other than the stainless steel piping itself

  13. VERTICAL ACCURACY COMPARISON OF DIGITAL ELEVATION MODEL FROM LIDAR AND MULTITEMPORAL SATELLITE IMAGERY

    Directory of Open Access Journals (Sweden)

    J. Octariady

    2017-05-01

    Full Text Available Digital elevation model serves to illustrate the appearance of the earth's surface. DEM can be produced from a wide variety of data sources including from radar data, LiDAR data, and stereo satellite imagery. Making the LiDAR DEM conducted using point cloud data from LiDAR sensor. Making a DEM from stereo satellite imagery can be done using same temporal or multitemporal stereo satellite imagery. How much the accuracy of DEM generated from multitemporal stereo stellite imagery and LiDAR data is not known with certainty. The study was conducted using LiDAR DEM data and multitemporal stereo satellite imagery DEM. Multitemporal stereo satellite imagery generated semi-automatically by using 3 scene stereo satellite imagery with acquisition 2013–2014. The high value given each of DEM serve as the basis for calculating high accuracy DEM respectively. The results showed the high value differences in the fraction of the meter between LiDAR DEM and multitemporal stereo satellite imagery DEM.

  14. Effect of heat treatment on the microstructure of Co-Cr-W alloy fabricated by laser additive manufacturing

    Science.gov (United States)

    Ren, Bo; Chen, Changjun; Zhang, Min

    2018-04-01

    Stellite 6 cobalt-based alloy powder was used to produce Co-Cr-W alloy using laser additive manufacturing technology, and then different heat treatment strategies were carried out on the deposited sample. The characteristics of microstructure under different heat treatment conditions were investigated using scanning electron microscopy with energy dispersive spectroscopy, transmission electron microscope, and x-ray diffraction. The results show that the as-deposited sample has few cracks or pores, and the microstructure is typical dendritic structure, and lamellar eutectic carbides are rich in Cr in interdendritic. The matrix mainly consists of γ phases and a few ɛ phases. Some γ phases transform into ɛ phases after 900°C/6 h aging treatment and lamellar eutectic carbides transform into blocky carbides presenting as a network, most of the carbides are rich in Cr and a few are rich in W. When heat treated at 1200°C/1 h followed by water cooling and then treated at 900°C/6 h followed by furnace cooling, it can be found that some γ phases transform into ɛ phases. The carbides transform into elliptical M23C6 carbides that are rich in Cr with the size of 1 to 3 μm and a part of W-rich carbides.

  15. Hardfacing and packings for improved valve performance

    International Nuclear Information System (INIS)

    Aikin, J.A.; Patrick, J.N.F.; Inglis, I.

    2003-01-01

    The CANDU Owners Group (COG), Chemistry, Materials and Components (CMC) Program has supported an ongoing program on valve maintenance and performance for several years. An overview is presented of recent work on iron-based hardfacing, packing qualification, friction testing of polytetrafluoroethylene (PTFE) packings, and an investigation of re-torquing valve packing. Based on this program, two new valve-packing materials have been qualified for use in CANDU stations. By doing this, CANDU maintenance can avoid having only one packing qualified for station use, as well as assess the potential impact of the industry trend towards using lower gland loads. The results from corrosion tests by AECL and the coefficient of friction studies at Battelle' s tribology testing facilities on Delcrome 910, an iron-based hardfacing alloy, indicate it is an acceptable replacement for Stellite 6 under certain conditions. This information can be used to update in-line valve purchasing specifications. The renewed interest in friction characteristics, and environmental qualification (EQ) of packing containing PTFE has resulted in a new test program in these areas. The COG-funded valve programs have resulted in modifications to design specifications for nuclear station in-line valves and have led to better maintenance practices and valve reliability. In the end, this means lower costs and cheaper electricity. (author)

  16. Overall strategy of Creys Malville power station dismantling

    International Nuclear Information System (INIS)

    Alphonse, P.

    2002-01-01

    The power station was stopped by a government decision following the elections in 1997. This shutdown was then made official by a letter dated April 1998 and the decree of December 1998. This was a non-technical shutdown and as such had not been envisaged; there has been no early warning. Current dismantling strategy: The studies leading to shutdown and then dismantling were engaged in 1998 based on a scenario with a status corresponding to IAEA level 2 until 2046. In 2001, EDF management made the decision to dismantle all the first generation power stations and Creys Malville between now and 2025. It should be noted that the presence of strongly irradiated stellite in the Creys Malville reactor would still require remote systems for working in the reactor block after 2046. The sequence of operations dictated by the dismantling strategy is as follows: eliminate the risks as soon as possible and in particular the risk related to the sodium, 3300 tonnes of which is kept in liquid form in the reactor vessel; dismantle the most active parts which are too radioactive to be sent to the existing or planned storage centres. This may lead to on-site storage to allow decay to occur before sending to a storage centre; planning of the work interventions in order to limit the costs

  17. An investigation of two-body abrasive wear of laser processed surfaces

    International Nuclear Information System (INIS)

    Abass, G.

    1995-01-01

    This paper reports two body abrasive wear studies of alloy and composite deposits produced with a 2 kW continuous wave CO/sub 2/ laser. Stellite alloy 6, Alloy 4815, Stainless steel and SiC powders were used to produce alloy and composite deposits on an En 3b mild steel substrate. The cladding material was injected into the laser produced melt pool by means of a pneumatic powder delivery system. In the present studies instead of using the conventional pin-on-disc method of wear measurement, a more realistic and practical wear testing procedure was adopted. The wear testing machine used was capable of measuring wear of three comparatively larger (30 x 30 x 10 mm) clad samples by abrading simultaneously against a revolving alumina disc. A comparative study of microstructure, hardness and wear of alloy and composite clads was made. The clad deposits were found sound and continuous. The hardness and wear resistance of the composites were markedly higher than that of the alloy clads. (author) 9 figs

  18. Engineer, design construct, test, and evaluate a pressurized fluidized-bed pilot plant using high-sulfur coal for production of electric power: Phase I. Preliminary engineering; Phase II. Final design; Phase III. Construction. Annual report, March 1, 1979-February 29, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    The extended test program on the SGT/PFB Technology Unit, previously placed in operation, was completed. Total operating time is 3378 which includes 2681 h burning coal and 1205 h total turbine engine operation. Significant performance and operational milestones, completed during the past year, included: over 2000 h on candidate heat exchanger tube materials at design temperature during which durability of iron-base alloy for PFB heat exchanger tubes was demonstrated; generated electric power with gas turbine operating on PFB coal combustion gas for 1000 h with no appreciable erosion or corrosion of turbine rotor blades and stator vanes; evaluated and improved hot gas cleanup system during which mean particle size of 1.3 Microns and a loading of 0.054 grains/Scf was achieved; and durability of hot/ash solids lock hopper valves for over 1000 h without leakage and stellite coated butterfly gas valve operating successfully for over 900 h in a highly erosive environment was demonstrated. Details of materials evolutions and corrosion rates, component performances and gaseous emission levels are presented.

  19. Stem thrust prediction model for W-K-M double wedge parallel expanding gate valves

    International Nuclear Information System (INIS)

    Eldiwany, B.; Alvarez, P.D.; Wolfe, K.

    1996-01-01

    An analytical model for determining the required valve stem thrust during opening and closing strokes of W-K-M parallel expanding gate valves was developed as part of the EPRI Motor-Operated Valve Performance Prediction Methodology (EPRI MOV PPM) Program. The model was validated against measured stem thrust data obtained from in-situ testing of three W-K-M valves. Model predictions show favorable, bounding agreement with the measured data for valves with Stellite 6 hardfacing on the disks and seat rings for water flow in the preferred flow direction (gate downstream). The maximum required thrust to open and to close the valve (excluding wedging and unwedging forces) occurs at a slightly open position and not at the fully closed position. In the nonpreferred flow direction, the model shows that premature wedging can occur during ΔP closure strokes even when the coefficients of friction at different sliding surfaces are within the typical range. This paper summarizes the model description and comparison against test data

  20. Friction behavior of cobalt base and nickel base hardfacing materials in high temperature sodium

    International Nuclear Information System (INIS)

    Mizobuchi, Syotaro; Kano, Shigeki; Nakayama, Kohichi; Atsumo, Hideo

    1980-01-01

    A friction behavior of the hardfacing materials such as cobalt base alloy ''Stellite'' and nickel base alloy ''Colmonoy'' used in the sliding components of a sodium cooled fast breeder reactor was investigated in various sodium environments. Also, friction tests on these materials were carried out in argon environment. And they were compared with those in sodium environment. The results obtained are as follows: (1) In argon, the cobalt base hardfacing alloy showed better friction behavior than the nickel base hardfacing alloy. In sodium, the latter was observed to have the better friction behavior being independent of the sodium temperature. (2) The friction coefficient of each material tends to become lower by pre-exposure in sodium. Particularly, this tendency was remarkable for the nickel base hardfacing alloy. (3) The friction coefficient between SUS 316 and one of these hardfacing materials was higher than that between latter materials. Also, some elements of hardfacing alloys were recognized to transfer on the friction surface of SUS 316 material. (4) It was observed that each tested material has a greater friction coefficient with a decrease of the oxygen content in sodium. (author)

  1. Wear of rolling element bearings in sodium

    International Nuclear Information System (INIS)

    Campbell, C.S.

    1976-01-01

    Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

  2. Canned motor pumps at Heavy Water Project, Baroda [Paper No.: II-2

    International Nuclear Information System (INIS)

    Batra, R.K.; Waishampayan, S.G.

    1981-01-01

    Heavy Water Project, Baroda is having special canned motor pumps for pumping ammonia and potassium amide. These pumps work under a pressure of 640 kg/cm 2 and are lubricated and cooled by the same fluid. These pumps are having special bearings consisting of mating surfaces of tungsten carbine Vs ceramic or stellite Vs carbon depending upon application. The total number of such pumps installed in the plant is around 52. These pumps being installed in high pressure vessels working at a pressure of 640 kg/cm 2 have special maintenance problems and need special care during maintenance. Pumps once boxed up are completely out of reach for immediate maintenance if needed. The failure of these pumps may mean a down time of one to two months for the plant. Besides above, there are multistage barrel type ammonia pumps with 24 stages developing a pressure of 140 kg/cm 2 . All these equipments need special maintenance methods as the problems faced are varied and difficult to solve. This paper deals with general and unique type of problems faced on these pumps. (author)

  3. Potential of direct metal deposition technology for manufacturing thick functionally graded coatings and parts for reactors components

    International Nuclear Information System (INIS)

    Thivillon, L.; Bertrand, Ph.; Laget, B.; Smurov, I.

    2009-01-01

    Direct metal deposition (DMD) is an automated 3D deposition process arising from laser cladding technology with co-axial powder injection to refine or refurbish parts. Recently DMD has been extended to manufacture large-size near-net-shape components. When applied for manufacturing new parts (or their refinement), DMD can provide tailored thermal properties, high corrosion resistance, tailored tribology, multifunctional performance and cost savings due to smart material combinations. In repair (refurbishment) operations, DMD can be applied for parts with a wide variety of geometries and sizes. In contrast to the current tool repair techniques such as tungsten inert gas (TIG), metal inert gas (MIG) and plasma welding, laser cladding technology by DMD offers a well-controlled heat-treated zone due to the high energy density of the laser beam. In addition, this technology may be used for preventative maintenance and design changes/up-grading. One of the advantages of DMD is the possibility to build functionally graded coatings (from 1 mm thickness and higher) and 3D multi-material objects (for example, 100 mm-sized monolithic rectangular) in a single-step manufacturing cycle by using up to 4-channel powder feeder. Approved materials are: Fe (including stainless steel), Ni and Co alloys, (Cu,Ni 10%), WC compounds, TiC compounds. The developed coatings/parts are characterized by low porosity (<1%), fine microstructure, and their microhardness is close to the benchmark value of wrought alloys after thermal treatment (Co-based alloy Stellite, Inox 316L, stainless steel 17-4PH). The intended applications concern cooling elements with complex geometry, friction joints under high temperature and load, light-weight mechanical support structures, hermetic joints, tubes with complex geometry, and tailored inside and outside surface properties, etc

  4. Effect of co-free valve on activity reduction in PWR

    International Nuclear Information System (INIS)

    Bahn, C.B.; Han, B.C.; Bum, J.S.; Hwang, I.S.; Lee, C.B.

    2002-01-01

    Radioactive nuclei, such as 68 Co and 60 Co, deposited on out-of-core surfaces in a pressurized water reactor (PWR) primary coolant system, are major sources of occupational radiation exposure to plant maintenance personnel and act as costly impediment to prompt and effective repairs. Valve hardfacing alloys exposed to primary coolant are considered as one of the main Co sources. To evaluate the Co-free valve, such as NOREM 02 and Deloro 50, the candidates for the alternative to Stellite 6, in a simulated PWR primary condition, SNU corrosion test loop (SCOTL) was constructed. For gate valves hard-faced with made of NOREM 02 and Deloro 50 hot cycling tests were conducted for up to 2,000 on-off cycles with cold leak tests at 1,000 cycle interval. It was observed that the leak rate of NOREM 02 (Fe-base) did not satisfy the nuclear grade valve leak criteria. After 1000 cycles test, while there was no leakage in case of Deloro 50 (Ni-base). Also, Deloro 50 showed no leakage after 2000 cycles. To estimate the activity reduction effect, we modified CRUDSIM-MIT which modeled the effects of coolant chemistry on the crud transport and activity buildup in the primary system of PWR. In the new code, crud evaluation and assessment (CREAT), 60 Co activity buildup prediction includes 1) Co-base valve replacement effect, 2) Co-base valve maintenance effect, and 3) control rod drive mechanism (CRDM) and main coolant pump (MCP) shaft contribution. CREAT predicted that the main contributor of Co activity buildup was the corrosion-induced release of Co from the steam generator (SG) tubing. With new SG's tubed with alloy 690, Korean Next Generation Reactor (APR-1400) is expected to have about 64% lower Co activity on SG surface. The use of all Co-free valves is expected to cut additional 8% of activity which is only marginal. (authors)

  5. Improvement of rotary specimen rack design

    International Nuclear Information System (INIS)

    Batch, J.M.; Gietzen, A.J.

    1978-01-01

    A redesign and verification test program has been completed on a new Rotary Specimen Rack ('Lazy Susan') design for the TRIGA Mark III. The purpose of the redesign was to solve a rotation problem which occurred at power levels of about 1 MW and above. The previous redesign effort on the Mark II-type lazy susan was made in 1967 when the bearing was changed to use stellite balls, spring-type separators and stainless-steel bearing races. An extensive test program at that time showed that the design gave excellent service under all anticipated operating conditions. Fifteen of these units have been installed in the past ten years and have been essentially trouble-free. Although the bearing design for the Mark III was very similar, the component layout was such that irradiation-induced heating with associated thermal expansion resulted in decreased bearing clearance and an increase in the required driving torque. The solution involved redesign and re-arrangement of the rack drive mechanism. A series of stringent operational proof tests were made under high temperature and temperature differential conditions which proved successful operation of the new design. The severe conditions under which these tests were performed uncovered further difficulties with the bearing and led to a re-evaluation of the bearing design. A new design was developed in which the spring separators were replaced by similar sized, cylindrical graphite spacers. The entire series of operational and life tests were repeated and the performance was outstanding. Acceptable wear characteristics of the spacers were verified and the bearing was noticeably smoother and quieter than with previous designs. A Mark III lazy susan of this new design was installed in a TRIGA about one year ago and operated at power levels up to 2 MW with excellent performance. The Mark II design has now been changed to incorporate the new drive and bearing design proven for the Mark III. (author)

  6. Chemistry in water reactors

    International Nuclear Information System (INIS)

    Hermansson, H.P.; Norring, K.

    1994-01-01

    The international conference Chemistry in Water Reactors was arranged in Nice 24-27/04/1994 by the French Nuclear Energy Society. Examples of technical program areas were primary chemistry, operational experience, fundamental studies and new technology. Furthermore there were sessions about radiation field build-up, hydrogen chemistry, electro-chemistry, condensate polishing, decontamination and chemical cleaning. The conference gave the impression that there are some areas that are going to be more important than others during the next few years to come. Cladding integrity: Professor Ishigure from Japan emphasized that cladding integrity is a subject of great concern, especially with respect to waterside corrosion, deposition and release of crud. Chemistry control: The control of the iron/nickel concentration quotient seems to be not as important as previously considered. The future operation of a nuclear power plant is going to require a better control of the water chemistry than achievable today. One example of this is solubility control via regulation in BWR. Trends in USA: means an increasing use of hydrogen, minimization of SCC/IASCC, minimization of radiation fields by thorough chemistry control, guarding fuel integrity by minimization of cladding corrosion and minimization of flow assisted corrosion. Stellite replacement: The search for replacement materials will continue. Secondary side crevice chemistry: Modeling and practical studies are required to increase knowledge about the crevice chemistry and how it develops under plant operation conditions. Inhibitors: Inhibitors for IGSCC and IGA as well for the primary- (zinc) as for the secondary side (Ti) should be studied. The effects and mode of operation of the inhibitors should be documented. Chemical cleaning: of heat transfer surfaces will be an important subject. Prophylactic cleaning at regular intervals could be one mode of operation

  7. Development surface modification technologies - A development of new nuclear materials by thin film deposition methods

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jong; Lee, Min Goo; Kim, Hyun Ho; Kim, Yong Il; Kwang, Hee Soo [Korea Advanced Institute of Scienec and Technology, Taejon (Korea, Republic of)

    1995-08-01

    Pitting corrosion of TiN-coted Inconel 600 in hightemperature chloride solution was studied. To improve the pitting resistance of Inconel 600 by depositing TiN thin film, TiN must have the thickness greater than a critical value at which the characteristics of the film itself appear. E{sub np}s of the TiN-coated sample were higher than those of the bare Inconel 600 at all the solution temperature implying that the TiN film improved the pitting resistance. The heavy defects on the surface of the substrate which were incompletely covered by TiN film served as the active sites for the pit nucleation. Fine polishing reduced those defects and improved the pitting resistance of the TiN-coated Inconel 600. The pit densities of the TiN-coated samples were much lower than those of the bare Inconel 600 at low chloride concentrations. However, at high chloride concentrations the TiN film failed to improve the pitting resistance of the Inconel. The TiN film deposited by ion-plating on Stellite was studied. The X-ray analysis shows that the deposited films were only in .delta.-TiN phase and the texture was changed from (111) to (200) with the increase of N{sub 2}/Ar ratio. The impurities in TiN films were carbon and oxygen. The amounts of these impurities were decreased greatly when the substrate bias, -200 V, was applied compared to no bias. 40 refs., 4 tabs., 20 figs. (author)

  8. Experience with dilute chemical decontamination in Indian Pressurized Heavy Water Reactors

    International Nuclear Information System (INIS)

    Velmurugan, S.; Rufus, A.L.; Sathyaseelan, V.S.; Subramanian, Veena; Mittal, V.K.; Narasimhan, S.V.

    2010-01-01

    Dilute Chemical Decontamination (DCD) process has been used in several full system and components of nuclear coolant systems to effectively remove the radioactive contaminants that causes radiation field and consequent MANREM problem. The DCD process uses chemicals in very low concentrations (millimolar) and dissolves the oxide film along with the activity incorporated in the oxide film. In DCD process operated under the regenerative mode, the chemical formulation spent in the process of oxide dissolution is replenished by passing through cation exchange columns. Finally, after achieving sufficient decontamination of the system/component, the added decontamination chemicals along with the activities and metal ions released during the process are removed by mixed bed ion exchange columns and the system is restored to normal operating condition in few days time. In PHWRs, the regenerative DCD process is applied for full primary coolant system decontamination. The chemicals are added directly to the heavy water coolant with the fuel in the core. In Indian PHWRs (MAPS-1 and 2, RAPS-1 and 2, NAPS-1 and 2 and KAPS-1), the process has been applied eleven times. A chemical formulation based on NTA, Citric acid and Ascorbic acid has been applied seven times with good results. Decontamination factors in the range 2-30 have been obtained in different components with good MANREM savings in the subsequent maintenance works. Efforts are on to modify the process to take care of the challenges posed by antimony isotope. An inhibitor (Rodine-92B) based process was successfully tested in NAPS-2 for removing antimony isotopes ( 122 Sb and 124 Sb). Further refining of the antimony removal process is being worked out. Similarly, the process is being modified to effectively remove the hotspot causing stellite particles in the moderator system of PHWRs. A permanganate based process has been developed and tested in several adjustor rod drive mechanisms in KAPS and NAPS. The experience of

  9. Potential of direct metal deposition technology for manufacturing thick functionally graded coatings and parts for reactors components

    Energy Technology Data Exchange (ETDEWEB)

    Thivillon, L.; Bertrand, Ph.; Laget, B. [Ecole Nationale d' Ingenieurs de Saint-Etienne (ENISE), DIPI Laboratory, 58 rue Jean Parot, 42023 Saint-Etienne cedex 2 (France); Smurov, I. [Ecole Nationale d' Ingenieurs de Saint-Etienne (ENISE), DIPI Laboratory, 58 rue Jean Parot, 42023 Saint-Etienne cedex 2 (France)], E-mail: smurov@enise.fr

    2009-03-31

    Direct metal deposition (DMD) is an automated 3D deposition process arising from laser cladding technology with co-axial powder injection to refine or refurbish parts. Recently DMD has been extended to manufacture large-size near-net-shape components. When applied for manufacturing new parts (or their refinement), DMD can provide tailored thermal properties, high corrosion resistance, tailored tribology, multifunctional performance and cost savings due to smart material combinations. In repair (refurbishment) operations, DMD can be applied for parts with a wide variety of geometries and sizes. In contrast to the current tool repair techniques such as tungsten inert gas (TIG), metal inert gas (MIG) and plasma welding, laser cladding technology by DMD offers a well-controlled heat-treated zone due to the high energy density of the laser beam. In addition, this technology may be used for preventative maintenance and design changes/up-grading. One of the advantages of DMD is the possibility to build functionally graded coatings (from 1 mm thickness and higher) and 3D multi-material objects (for example, 100 mm-sized monolithic rectangular) in a single-step manufacturing cycle by using up to 4-channel powder feeder. Approved materials are: Fe (including stainless steel), Ni and Co alloys, (Cu,Ni 10%), WC compounds, TiC compounds. The developed coatings/parts are characterized by low porosity (<1%), fine microstructure, and their microhardness is close to the benchmark value of wrought alloys after thermal treatment (Co-based alloy Stellite, Inox 316L, stainless steel 17-4PH). The intended applications concern cooling elements with complex geometry, friction joints under high temperature and load, light-weight mechanical support structures, hermetic joints, tubes with complex geometry, and tailored inside and outside surface properties, etc.

  10. Potential of direct metal deposition technology for manufacturing thick functionally graded coatings and parts for reactors components

    Science.gov (United States)

    Thivillon, L.; Bertrand, Ph.; Laget, B.; Smurov, I.

    2009-03-01

    Direct metal deposition (DMD) is an automated 3D deposition process arising from laser cladding technology with co-axial powder injection to refine or refurbish parts. Recently DMD has been extended to manufacture large-size near-net-shape components. When applied for manufacturing new parts (or their refinement), DMD can provide tailored thermal properties, high corrosion resistance, tailored tribology, multifunctional performance and cost savings due to smart material combinations. In repair (refurbishment) operations, DMD can be applied for parts with a wide variety of geometries and sizes. In contrast to the current tool repair techniques such as tungsten inert gas (TIG), metal inert gas (MIG) and plasma welding, laser cladding technology by DMD offers a well-controlled heat-treated zone due to the high energy density of the laser beam. In addition, this technology may be used for preventative maintenance and design changes/up-grading. One of the advantages of DMD is the possibility to build functionally graded coatings (from 1 mm thickness and higher) and 3D multi-material objects (for example, 100 mm-sized monolithic rectangular) in a single-step manufacturing cycle by using up to 4-channel powder feeder. Approved materials are: Fe (including stainless steel), Ni and Co alloys, (Cu,Ni 10%), WC compounds, TiC compounds. The developed coatings/parts are characterized by low porosity (<1%), fine microstructure, and their microhardness is close to the benchmark value of wrought alloys after thermal treatment (Co-based alloy Stellite, Inox 316L, stainless steel 17-4PH). The intended applications concern cooling elements with complex geometry, friction joints under high temperature and load, light-weight mechanical support structures, hermetic joints, tubes with complex geometry, and tailored inside and outside surface properties, etc.

  11. Corrosion surveillance of the chemical decontamination process in Kuosheng nuclear power plant

    International Nuclear Information System (INIS)

    Wang, L.H.

    2002-01-01

    The Piping Recirculation System (RRS) and reactor water clean-up system (RWCU) of Kuosheng Nuclear Power Plant of Taiwan Power Company were decontaminated by CORD process of Framatome ANP GmbH during the outage at October 2001. This is the first time that CORD process was adopted and applied in Taiwan Nuclear Power Plant. To verify minor corrosion damage and correct process control, the material corrosion condition was monitored during all the stages of the chemical decontamination work. Three kinds of specimen were adopted in this corrosion monitoring, including corrosion coupons for weight loss measurements, electrochemical specimens for on-line corrosion monitoring, and WOL specimens (wedge opening loaded) for stress corrosion evaluation. The measured metal losses from nine coupon materials did not reveal any unexpected or intolerable high corrosion damage from the CORD UV or CORD CS processes. The coupon materials included type 304 stainless steel (SS) with sensitized and as-received thermal history, type 308 weld filler, type CF8 cast SS, nickel base alloy 182 weld filler, Inconel 600, Stellite 6 hard facing alloy, NOREM low cobalt hard facing alloy, and A106B carbon steel (CS). The electrochemical noise (ECN) measurements from three-electrode electrochemical probe precisely depicted the metal corrosion variation with the decontamination process change. Most interestingly, the estimated trend of accumulated metal loss is perfectly corresponding to the total removed activities. The ECN measurements were also used for examining the effect of different SS oxide films pre-formed in NWC and HWC on the decontamination efficiency, and for evaluating the galvanic effect of CS with SS. The existing cracks did not propagate further during the decontamination. The average decontamination factors achieved were 50.8 and 4.2 respectively for RRS and RWCU. (authors)

  12. Analysis of PTA hardfacing with CoCrWC and CoCrMoSi alloys

    Directory of Open Access Journals (Sweden)

    Adriano Scheid

    2013-12-01

    Full Text Available CoCrWC alloys are widely used to protect components that operate under wear and high temperature environments. Enhanced performance has been achieved with the CoCrMoSi alloys but processing this alloy system is still a challenge due to the presence of the brittle Laves phase, particularly when welding is involved. This work evaluated Plasma Transferred Arc coatings processed with the Co-based alloy CoMoCrSi - Tribaloy T400, reinforced with Laves phase, comparing its weldability to the CoCrWC - Stellite 6, reinforced with carbides. Coatings were also analyzed regarding the response to temperature exposure at 600°C for 7 days and subsequent effect on microstructure and sliding abrasive wear. Coatings characterization was carried out by light and scanning electron microscopy, X-ray diffraction and Vickers hardness. CoCrWC coatings exhibited a Cobalt solid solution dendritic microstructure and a thin interdendritic region with eutectic carbides, while CoCrMoSi deposits exhibit a large lamellar eutectic region of Laves phase and Cobalt solid solution and a small fraction of primary Laves phase. Although phase stability was observed by X-ray diffraction, coarsening of the microstructure occurred for both alloys. CoCrMoSi showed thicker lamellar Laves phase and CoCrWC coarser eutectic carbides. Coatings stability assessed by wear tests revealed that although the wear rate of the as-deposited CoCrMoSi alloy was lower than that of CoCrWC alloy its increase after temperature exposure was more significant, 22% against 15%. Results were discussed regarding the protection of industrial components in particular, bearings in 55AlZn hot dip galvanizing components.

  13. Control rod upper pin and roller removal and replacement

    International Nuclear Information System (INIS)

    Giordano, B.

    1995-01-01

    There has been increasing utility interest in removing cobalt sources as a means to minimize dose rates and shipping costs associated with operations, maintenance, shipping and radioactive waste disposal. This activation product accounts for approximately 80% of the dose rates at a plant. Estimates suggest that older (original equipment) control rod blades (CRBs) using stellite rollers and Haynes Alloy 25 pins can contribute as much as 43% of the cobalt in the plant. Since CRBs are the most concentrated source of cobalt in the reactor vessel, pin and roller (P ampersand R) replacement will provide significant reductions in cobalt-60 levels. The reductions will be measurable within 2 years, and should plateau within 5 to 6 years. This paper described a new, simple, cost effective, field proven in-situ method to replace these high source term contributing components and return the CRB to the reactor core for continued service. The paper also briefly describes a methodology that has been developed to estimate the labor and material costs along with a man-rem dollar savings for removal of the upper P ampersand Rs from in-service CRBs purchased prior to 1982. This method permits comparison to the cost of early replacement of CRBs. The result of this study is an EXCEL spreadsheet cost/benefit analysis that can be made plant specific by incorporation of plant data. The Analysis shows that the removal of P ampersand Rs can be beneficial for a Co-60 contribution as low as 5-10%. Recent interest by non-utility radioactive material users in obtaining the removed P ampersand Rs may further increase the benefit and reduce the cost associated with in-situ removal

  14. Corrosion behaviour and surface analysis of a Co-Cr and two Ni-Cr dental alloys before and after simulated porcelain firing.

    Science.gov (United States)

    Qiu, Jing; Yu, Wei-Qiang; Zhang, Fu-Qiang; Smales, Roger J; Zhang, Yi-Lin; Lu, Chun-Hui

    2011-02-01

    This study evaluated the corrosion behaviour and surface properties of a commercial cobalt-chromium (Co-Cr) alloy and two nickel-chromium (Ni-Cr) alloys [beryllium (Be)-free and Be-containing] before and after a simulated porcelain-firing process. Before porcelain firing, the microstructure, surface composition and hardness, electrochemical corrosion properties, and metal-ion release of as-cast alloy specimens were examined. After firing, similar alloy specimens were examined for the same properties. In both as-cast and fired conditions, the Co-Cr alloy (Wirobond C) showed significantly more resistance to corrosion than the two Ni-Cr alloys. After firing, the corrosion rate of the Be-free Ni-Cr alloy (Stellite N9) increased significantly, which corresponded to a reduction in the levels of Cr, molybdenum (Mo), and Ni in the surface oxides and to a reduction in the thickness of the surface oxide film. The corrosion properties of the Co-Cr alloy and the Be-containing Ni-Cr alloy (ChangPing) were not significantly affected by the firing process. Porcelain firing also changed the microstructure and microhardness values of the alloys, and there were increases in the release of Co and Ni ions, especially for Ni from the Be-free Ni-Cr alloy. Thus, the corrosion rate of the Be-free Ni-Cr alloy increased significantly after porcelain firing, whereas the firing process had little effect on the corrosion susceptibility of the Co-Cr alloy and the Be-containing Ni-Cr alloy. © 2011 Eur J Oral Sci.

  15. Erosion resistance comparison of alternative surface treatments

    Science.gov (United States)

    Česánek, Z.; Schubert, J.; Houdková, Š.

    2017-05-01

    Erosion is a process characterized by the particle separation and the damage of component functional surfaces. Thermal spraying technology HP/HVOF (High Pressure / High Velocity Oxygen Fuel) is commonly used for protection of component surfaces against erosive wear. Alloy as well as cermet based coatings meet the requirements for high erosion resistance. Wear resistance is in many cases the determining property of required component functioning. The application suitability of coating materials is particularly influenced by different hardness. This paper therefore presents an erosion resistance comparison of alloy and cermet based coatings. The coatings were applied on steel substrates and were subjected to the erosive test using the device for evaluation of material erosion resistance working on the principle of centrifugal erodent flow. Abrasive sand Al2O3 with grain size 212-250 μm was selected as an erosive material. For this purpose, the specimens were prepared by thermal spraying technology HP/HVOF using commercially available powders Stellite 6, NiCrBSi, Cr3C2-25%NiCr, Cr3C2-25%CoNiCrAlY, Hastelloy C-276 and experimental coating TiMoCN-29% Ni. Erosion resistance of evaluated coatings was compared with erosive resistance of 1.4923 high alloyed steel without nitridation and in nitrided state and further with surface treatment using technology PVD. According to the evaluation, the resulting erosive resistance depends not only on the selected erodent and surface protection, but also on the erodent impact angle.

  16. Microstructural evolution and control in laser material processing

    International Nuclear Information System (INIS)

    Kaul, R.; Nath, A.K.

    2005-01-01

    Laser processing, because of its characteristic features, often gives rise to unique microstructure and properties not obtained with other conventional processes. We present various diverse laser processing case studies involving control of microstructure through judicious selection of processing parameters carried out with indigenously developed high power CO 2 lasers. The first study describes microstructural control during end plug laser welding of PFBR fuel pin, involving crack pone alloy D9 tube and type 316 M stainless steel (SS) plug, through preferential displacement of focused laser beam. Crater and associated cracks were eliminated by suitable laser power ramping. Another case study describes how low heat input characteristics of laser cladding process has been exploited for suppressing dilution in 'Colomony 6' deposits on austenitic SS. The results are in sharp contrast to extensive dilution noticed in Colmony 6 hard faced deposits made by GTAW. A novel laser surface melting (LSM) treatment for type 316 (N) SS weld metal has been developed to generate a sensitization-resistant microstructure which leads to enhanced resistance against intergranular corrosion (IGC). IGC resistance of laser treated surface has been found to be critically dependent on laser processing parameters. Experimental observations have been analyzed with thermal simulation. We have also studied the effect of laser beam spatial intensity profile on the microstructure in LSM. We have developed laser-assisted graded hard facing of austenitic SS substrate with Stellite 6 which, in contrast to direct deposition either by laser or GTAW, produced smooth transition in chemical composition and hardness used to control grain coarsening and martensite formation in type 430 SS weldment. Laser rapid manufacturing (LRM) is emerging as a new rapid and cost effective process for low volume fabrication, esp. of expensive materials. The talk will also present microstructural characteristics of laser

  17. Reducing plant radiation fields by source term reduction - tracking cobalt and antimony to their sources at Gentilly-2

    International Nuclear Information System (INIS)

    Gauthier, P.; Guzonas, D.A.

    2006-01-01

    Gentilly-2 NGS is experiencing high radiation fields in the fuelling machine vaults. These high fields make maintenance outages more expensive and their management more complicated. As part of the station refurbishment project, a task group was created to identify the cause of the high fields and make recommendations to prevent their reoccurrence in the second (post-refurbishment) operating cycle. To identify the root cause of the problem, the task group decided to analyse the primary heat transport system (PHTS), the fuel handling system and their inter-relation. Gentilly-2 has had to manage a unique (to CANDU) problem arising from antimony released from the main heat transport pump seals. Antimony deposits on in-core surfaces, becomes activated, and subsequently can be released, especially under oxidizing coolant conditions. It then becomes incorporated into the magnetite deposits on PHTS piping, including the steam generators and inlet feeders. Gentilly-2 has focused a great deal of effort on managing antimony over the last 15 years. As a result of these initiatives, radioantimony fields have been quite effectively managed since 1997, resulting in a decrease in their relative contribution to the total fields. The decrease in radioantimony fields highlighted the significant contribution of 60 Co cobalt activity; the high levels of both radioantimony and 60 Co differentiate Gentilly-2 from other CANDU 6 plants. Two types of 59 Co sources are present in the CANDU PHTS. High surface area materials such as steam generator tubes and feeder pipes contain trace concentrations of 59 Co as an impurity, which can be released by corrosion. Low surface area materials such as Stellites contain high concentrations of 59 Co that can be released as either corrosion or wear products. After assessing potential cobalt sources, the task group concluded that PHTS materials were not likely the origin of the high 60 Co fields. The major PHTS components identified as cobalt sources have

  18. Tribocorrosion in pressurized high temperature water: a mass flow model based on the third body approach

    Energy Technology Data Exchange (ETDEWEB)

    Guadalupe Maldonado, S.

    2014-07-01

    Pressurized water reactors (PWR) used for power generation are operated at elevated temperatures (280-300 °C) and under higher pressure (120-150 bar). In addition to these harsh environmental conditions some components of the PWR assemblies are subject to mechanical loading (sliding, vibration and impacts) leading to undesirable and hardly controllable material degradation phenomena. In such situations wear is determined by the complex interplay (tribocorrosion) between mechanical, material and physical-chemical phenomena. Tribocorrosion in PWR conditions is at present little understood and models need to be developed in order to predict component lifetime over several decades. The goal of this project, carried out in collaboration with the French company AREVA NP, is to develop a predictive model based on the mechanistic understanding of tribocorrosion of specific PWR components (stainless steel control assemblies, stellite grippers). The approach taken here is to describe degradation in terms of electro-chemical and mechanical material flows (third body concept of tribology) from the metal into the friction film (i.e. the oxidized film forming during rubbing on the metal surface) and from the friction film into the environment instead of simple mass loss considerations. The project involves the establishment of mechanistic models for describing the single flows based on ad-hoc tribocorrosion measurements operating at low temperature. The overall behaviour at high temperature and pressure in investigated using a dedicated tribometer (Aurore) including electrochemical control of the contact during rubbing. Physical laws describing the individual flows according to defined mechanisms and as a function of defined physical parameters were identified based on the obtained experimental results and from literature data. The physical laws were converted into mass flow rates and solved as differential equation system by considering the mass balance in compartments

  19. Regulatory actions towards dose reduction at Atucha 1 NPS

    International Nuclear Information System (INIS)

    Spano, F.; Curti, A.R.; Telleria, D.M.; Rudelli, M.D.

    1998-01-01

    Atucha 1, a nuclear power plant designed in the late sixties, is in commercial operation since June 1974. In some internal components such as the coolant channels, the station has Stellite-6, a high cobalt content alloy (up to 60%) for hard-facing application. The erosion and corrosion processes on the surfaces of the piping components of the primary coolant and moderator systems generate a varied type of particles oxides called 'crud'. The crud and cobalt 60 produced by neutron activation of cobalt are transferred by the water along the circuit of the coolant and moderator systems, producing deposits on internal surfaces. The cobalt deposits are dominant in radiation fields at working locations. For years, the Authority allowed a considerable number of station workers incurring doses near the limit since that installation had been built previously to introduction of the optimisation concept by ICRP publication 26. The recommendations included in ICRP publication 60 made more than difficult the radiological situation at the Atucha 1. For the facility, to comply with the new limit established by the Authority in January 1995, meant to carry out a substantial modification of the radiological conditions, specially the radiation fields due to cobalt 60. Some options to reduce individual and collective doses were analysed by the Authority. To carry out the evaluation of the deposit mechanisms and the real activity level of cobalt 60, a model of compartments connected by means of constant transfer coefficients was designed. It was concluded that there was a necessity to the change of coolant channels by new ones free of cobalt. It has been shown experimentally that radiation fields and occupational doses were reduced, due to the replacement programme carried out by the utility, in a similar way to the model predictions. At present after more than three years from the beginning of the application of the new limits, and after carrying out partially the tasks for the

  20. INVESTIGATION IN HARDSURFACING A NICKEL-COPPER ALLOY (MONEL400)

    International Nuclear Information System (INIS)

    CZAJKOWSKI, C.; BUTTERS, M.

    2001-01-01

    Brookhaven National Laboratory (BNL) investigated the causes of weldability problems and materials failures encountered with the application of Monel (Ni-Cu) 400 as a base material and Stellite 6 (Co-Cr) as the hard-surfacing material when using the oxyacetylene welding process. This work was performed under a cooperative research and development agreement (CRADA) with the Target Rock Division of the Curtiss-Wright Flow Control Corporation. BNL evaluated two heats of Monel 400 material. One of the heats had performed well during manufacturing, producing an acceptable number of ''good'' parts. The second heat had produced some good parts but also exhibited a peculiar type of hardsurfacing/base metal collapse during the welding process. A review of the chemistry on the two heats of material indicated that they both met the chemical requirements for Monel400. During examination of the failed component, linear indications (cracks) were evident on the valve body, both on the circumferential area (top of valve body) and below the hard surfaced weld deposit. independent measurements also indicated that the two heats met the specification requirement for the material. The heat affected zone (HAZ) also contained linear discontinuities. The valve body was welded using the oxyacetylene welding process, a qualified and skilled welder, and had been given a pre-heat of between 1400-1600 F (760-871 C), which is the Target Rock qualified procedure requirement. Both original suppliers performed mechanical testing on their material that indicated the two heats also met the mechanical property requirements of the specification. The BNL investigation into the cause of the differences between these heats of material utilized the following techniques: (1) Heat Treatment of both heats of material; (2) Hardness testing; (3) Optical microscopy; (4) Scanning electron microscope (SEM)/Fractography; and (5) Energy dispersive spectroscopy (EDS). The report concludes that the cause of the

  1. Improved design and durability of aluminum die casting horizontal shot sleeves

    Science.gov (United States)

    Birceanu, Sebastian

    substrate performed very well as long as the coating was maintained. Nitrided H13 sleeve showed extensive damage that occurred as early as 200 cycles. The nitrided layer only slowed down the diffusion process and dissolution took place at a higher rate as soon as the layer wore off. Stellite 6 sleeve also showed considerable wear under the action of molten aluminum.

  2. Thin coatings for heavy industry: Advanced coatings for pipes and valves

    Science.gov (United States)

    Vernhes, Luc

    Pipes and valves are pressure vessels that regulate the flow of materials (liquids, gases, and slurries) by controlling the passageways. To optimize processes, reduce costs, and comply with government regulations, original equipment manufacturers (OEMs) must maintain their products in state-of-the-art condition. The first valves were invented over 3,000 years ago to supply water to farms and cities. They were made with bronze alloys, providing good corrosion resistance and acceptable tribological performance. The industrial revolution drove manufacturers to develop new and improved tribological materials. In the 20th century, innovative alloys such as Monel copper-nickel and Stellite cobalt-chrome as well as hard chrome plating were introduced to better control tribological properties and maximize in-service life. Since then, new materials have been regularly introduced to extend the range of applications for valves. For example, Teflon fluoropolymers are used in corrosive chemical and petrochemical processes, the nickel-based superalloys Hastelloy and Inconel for petrochemical applications, and creep-resistant chromium-rich F91 steel for supercritical power plants. Recently, the valve industry has embraced the use of hard thermal sprayed coatings for the most demanding applications, and is investing heavily in research to develop the most suitable coatings for specific uses. There is increasing evidence that the optimal solution to erosive, corrosive, and fretting wear problems lies in the design and manufacture of multi-layer, graded, and/or nanostructured coatings and coating systems that combine controlled hardness with high elastic modulus, high toughness, and good adhesion. The overall objectives of this thesis were 1) to report on advances in the development of structurally controlled hard protective coatings with tailored mechanical, elastoplastic, and thermal properties; and 2) to describe enhanced wear-, erosion-, and corrosion-resistance and other

  3. Material compatibility evaluataion for DWPF nitric-glycolic acid - literature review

    International Nuclear Information System (INIS)

    Mickalonis, J.I; Skidmore, T.E.

    2013-01-01

    Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid. The reported corrosion rates and degradation characteristics have shown the following for the materials of construction: For C276 alloy, the primary material of construction for the CPC vessels, corrosion rates of either 2 or 20 mpy were reported up to a temperature of 93 deg C; For the austenitic stainless steels, 304L and 316L, variable rates were reported over a range of temperatures, varying from 2 mpy up to 200 mpy (at 100 deg C); For 690, G30, Allcorr, Ultimet and Stellite alloys no data were available; and, For relevant polymers where data are available, the data suggests that exposure to glycolic acid is not detrimental. The literature data had limited application to the DWPF process since only the storage and feed vessels, pumps and piping used to handle the glycolic acid are directly covered by the available data. These components are either 304L or 316L alloys for which the literature data is inconsistent (See Bullet 2 above). Corrosion rates in pure glycolic acid solutions also are not representative of the DWPF process streams. This stream is complex and contains aggressive species, i.e. chlorides, sulfates, mercury, as well as antifoaming agents which cumulatively have an unknown effect on the corrosion rates of the materials of construction. Therefore, testing is recommended to investigate any synergistic effects of the aggressive

  4. Re-Os systematics and geochemistry of cobaltite (CoAsS) in the Idaho cobalt belt, Belt-Purcell Basin, USA: Evidence for middle Mesoproterozoic sediment-hosted Co-Cu sulfide mineralization with Grenvillian and Cretaceous remobilization

    Science.gov (United States)

    Saintilan, N.J.; Creaser, R.A.; Bookstrom, Arthur A.

    2017-01-01

    We report the first study of the Re-Os systematics of cobaltite (CoAsS) using disseminated grains and massive sulfides from samples of two breccia-type and two stratabound deposits in the Co-Cu-Au Idaho cobalt belt (ICB), Lemhi subbasin to the Belt-Purcell Basin, Idaho, USA. Using a 185Re + 190Os spike solution, magnetic and non-magnetic fractions of cobaltite mineral separates give reproducible Re-Os analytical data for aliquot sizes of 150 to 200 mg. Cobaltite from the ICB has highly radiogenic 187Os/188Os ratios (17–45) and high 187Re/188Os ratios (600–1800) but low Re and total Os contents (ca. 0.4–4 ppb and 14–64 ppt, respectively). Containing 30 to 74% radiogenic 187Os, cobaltite from the ICB is amenable to Re-Os age determination using the isochron regression approach.Re-Os data for disseminated cobaltite mineralization in a quartz-tourmaline breccia from the Haynes-Stellite deposit yield a Model 1 isochron age of 1349 ± 76 Ma (2σ, n = 4, mean squared weighted deviation MSWD = 2.1, initial 187Os/188Os ratio = 4.7 ± 2.2). This middle Mesoproterozoic age is preserved despite a possible metamorphic overprint or a pulse of metamorphic-hydrothermal remobilization of pre-existing cobaltite that formed along fold cleavages during the ca. 1190–1006 Ma Grenvillian orogeny. This phase of remobilization is tentatively identified by a Model 3 isochron age of 1132 ± 240 Ma (2σ, n = 7, MSWD = 9.3, initial 187Os/188Os ratio of 9.0 ± 2.9) for cobaltite in the quartz-tourmaline breccia from the Idaho zone in the Blackbird mine.All Mesoproterozoic cobaltite mineralization in the district was affected by greenschist- to lower amphibolite-facies (garnet zone) metamorphism during the Late Jurassic to Late Cretaceous Cordilleran orogeny. However, the fine- to coarse-grained massive cobaltite mineralization from the shear zone-hosted Chicago zone, Blackbird mine, is the only studied deposit that has severely disturbed Re

  5. New Instruments and Principles for the Dimensional Measurement and Measurement of Spacing of Reactor Components; Nouveaux Instruments et Procedes de Mesure des Dimensions et de l'Espacement des Elements d'un Reacteur; Novye pribory i printsipy izmereniya razmerov i raspolozheniya komponentov reaktora; Nuevos Instrumentos y Principios para Medir las Dimensiones y la Separacion Entre Componentes de Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, P. [Institut Dr. Foerster, Reutlingen, Federal Republic of Germany (Germany)

    1965-09-15

    Full text: The measurement of wall thickness of austenitic and non-ferrous sheets, tubes and containers is presented. Two methods for contactless measurement are discussed: eddy- current method for measuring the thickness of non-ferrous and austenitic sheets and containers by means of transition coils; eddy-current measurement of the wall thickness of tubes by means of feed-through coils. Suitable instruments and their application are shown. Wall-thickness measurement on non-ferrous reactor assemblies by the ''magnetic ball method'' is also discussed. The principle of this new type of measurement is explained, its range of use - especially for spot- measurements - is discussed, and a practical instrument is described. Measurement of non-magnetic coatings on magnetic base materials is discussed. The measurement principles (magnetic DC and AC field methods) are explained and instruments for measurement of nonmagnetic coatings between 3-{mu}m and 20-mm thickness are shown. The special problem of measurement of stellite deposits on ferritic walls of reactor vessels is discussed. The measurement of electrically non-conductive coatings on base materials consisting of non-ferrous metals; and the principle of measurement (eddy currents) are explained. An instrument for this purpose is shown and typical examples of measurements are given. Contactless in-line measurements of physical dimensions of metallic reactor components are given. Various methods for ferrous and non-ferrous metals are explained (magnetic DC and AC field method, eddy-current methods). Instruments and examples for remote measurements of diameter, ovality, distortion etc., of reactor components are described, and methods of measuring the spacing of such components in the ''hot'' zone of the reactor are shown. An instrument for recording the surface profile and for direct reading the roughness values (''Rauhtiefe'', ''Glaettungstiefe'', CLA value and RMS value) is shown. Typical examples of the use of the

  6. Structurally Integrated Coatings for Wear and Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Beardsley, M. Brad; Sebright, Jason L.

    2008-11-18

    techniques, balanced with overall materials performance. State-of-the-art design and simulation capabilities were used to guide materials and process refinement. Caterpillar was the lead of the multi-partner collaborative project. Specific tasks were performed by the partners base on their unique capabilities. The project team was selected to include leaders in the field of material development, processing, modeling, and material characterization. Specifically, industrial members include the suppliers Deloro Stellite and Powder Alloy Corporation., who provided the experimental alloys and who aided in the development of the costs for the alloys, the Missouri University of Science and Technology and Iowa State University, who provided help in the alloy development and material characterization, QuesTek Innovations, a small company specializing the microstructural modeling of materials, and the DOE laboratories, Oak Ridge National Laboratory and National Energy Technology Laboratory (Albany), who provided unique coating process capability and wear characterization testing. The technologies developed in this program are expected to yield energy savings of about 50% over existing technologies, or 110 trillion BTUs per year by 2020 when fully implemented. Primary applications by Caterpillar are to replace the surface of machine components which are currently carburized and heat treated with new cladding materials with double the wear life. The new cladding technologies will consume less energy than carburizing. Thus, nearly 50% energy savings can be expected as a result from elimination of the heat treat process and the reduce wear of the materials. Additionally, when technologies from this project are applied on titanium or other non-ferrous substrates to make lighter weight, more wear resistant, and more efficient structures, significant fuel savings can be realized. With the anticipated drastic reduction in cost for refining titanium-containing ores, the usage of titanium

  7. Treatment of core components from nuclear power plants with PWR and BWR reactors - 16043

    International Nuclear Information System (INIS)

    Viermann, Joerg; Friske, Andreas; Radzuweit, Joerg

    2009-01-01

    duty manipulator has been designed to process the components to package them into the smaller MOSAIK R II casks. The different ways of treatment of core components will be described and compared on the basis of some exemplary treatment campaigns. In conclusion, The first campaign of external conditioning of BWR control elements has established that this technique is an effective procedure. Some conclusions can be drawn for the next conditioning campaigns: One advantage of the external conditioning process is the short handling time involved in loading large casks in the FA storage pool of the NPP. This is particularly important in a NPP that is still in operation because only a limited time window is available for underwater work in the FA storage pool. Owing to the greater density of the compacted CE material, the specific Co-60 activities of the CE to be transported from the NPP must be limited to a mean value of 1 E+11 Bq/kg, otherwise the MOSAIK R II-15 casks could be overloaded. This means that the CE must be given a decay time of at least approx. 8 - 10 years, depending on the level of activation, before they are transported from the NPP. For the next cask loadings, it must be checked whether the internal Pb shielding of the MOSAIK R II-15 U EI casks should be increased to the maximum possible value of 95 mm (the maximum thickness of the shielding is limited by the pellet diameter). The procedure to separate the upper pins and rollers out of the CE requires improvement to prevent the remains of the stellite axles in the upper sections of the CE from causing hot spots in the MOSAIK R II-15 casks. If these conclusions are taken into account, good conditioning results can be expected for the CE from German BWRs that still require disposal (currently approx. 600 CE). With regard to the disposal capacity the external disposal of CE must be planned on a long-term basis owing to the limited capacities of the MAW cell and the fact that there is only one MOSAIK R 80T