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Relation of microstructure to high-temperature properties of a wrought cobalt-base alloy Stellite 21 (AMS 5385)

Description: Report presenting an investigation to determine the effects of microstructure on the stress-rupture life of heat-treated wrought Stellite 21 under stress and temperature conditions comparable to those encountered during engine operation of turbine blades and to correlate with other microstructure properties. Results regarding the stress-rupture life, elongation, hardness, metallographic examination, and room-temperature tensile tests are provided.
Date: March 1954
Creator: Clauss, F. J. & Weeton, J. W.
Partner: UNT Libraries Government Documents Department

Investigation of engine performance and high-temperature properties of precision-cast turbine blades of high carbon Stellite 21 and controlled grain-size-Stellite 21

Description: Report presenting an investigation to determine the effect of controlled grain size and increased carbon content on engine performance and high-temperature properties of precision-cast Stellite 21 turbine blades. Results regarding blade stresses, engine operation, and metallurgical examination are provided.
Date: June 23, 1952
Creator: Yaker, Charles; Garrett, Floyd B. & Sikora, Paul F.
Partner: UNT Libraries Government Documents Department

Effects of some solution treatments followed by an aging treatment on the life of small cast gas-turbine blades of a cobalt-chromium-base alloy II: effect of selected combinations of soaking time, temperature, and cooling rate

Description: Report presenting an investigation to determine the effects of various heat treatments on the microstructure and life of small cast turbine blades of Haynes Stellite alloy 21. Six heat treatments were tested on twenty blades. Results regarding the time of failure for individual blades and tests of joint equality are provided.
Date: October 1951
Creator: Hoffman, C. A. & Robards, C. F.
Partner: UNT Libraries Government Documents Department

Adhesive and protective characteristics of ceramic coating A-417 and its effect on engine life of forged Refractaloy-26 (AMS 5760) and cast stellite 21 (AMS 5385) turbine blades

Description: The adhesive and protective characteristics of National Bureau of Standards Coating A-417 were investigated, as well as the effect of the coating on the life of forged Refractaloy 26 and cast Stellite 21 turbine blades. Coated and uncoated blades were run in a full-scale J33-9 engine and were subjected to simulated service operations consisting of consecutive 20-minute cycles (15 min at rated speed and approximately 5 min at idle). The ceramic coating adhered well to Refractaloy 26 and Stellite 21 turbine blades operated at 1500 degrees F. The coating also prevented corrosion of the Refractaloy 26, a corrosion-sensitive nickel-base alloy, and of the Stellite 21, a relatively corrosion-resistant cobalt-base alloy. Although the coating prevented corrosion of both alloys, it had no apparent effect on blade life.
Date: February 12, 1953
Creator: Garrett, Floyd B. & Gyorgak, Charles A.
Partner: UNT Libraries Government Documents Department

Effect of heat treatment upon the microstructure and hardness of a wrought cobalt-base alloy stellite 21 (AMS 5385)

Description: Report presenting an investigation of the response of wrought Stellite 21, a typical cobalt-base alloy, to heat treatment. The alloy was solution-treated and transformed by aging and isothermal transformation at temperatures of 1200 to 1950 degrees Fahrenheit for periods of 5 minutes to 72 hours. Results regarding the solution-treated structure, precipitation by isothermal transformation, precipitation by aging, grain boundary behavior, and hardness are provided.
Date: March 1954
Creator: Clauss, F. J. & Weeton, J. W.
Partner: UNT Libraries Government Documents Department

Tribological Behavior of Spark Plasma Sintered Tic/graphite/nickel Composites and Cobalt Alloys

Description: Monolithic composites are needed that combine low friction and wear, high mechanical hardness, and high fracture toughness. Thin films and coatings are often unable to meet this engineering challenge as they can delaminate and fracture during operation ceasing to provide beneficial properties during service life. Two material systems were synthesized by spark plasma sintering (SPS) and were studied for their ability to meet these criteria. A dual hybrid composite was fabricated and consisted of a nickel matrix for fracture toughness, TiC for hardness and graphite for solid/self‐lubrication. An in‐situ reaction during processing resulted in the formation of TiC from elemental Ti and C powders. The composition was varied to determine its effects on tribological behavior. Stellite 21, a cobalt‐chrome‐molybdenum alloy, was also produced by SPS. Stellite 21 has low stacking fault energy and a hexagonal phase which forms during sliding that both contribute to low interfacial shear and friction. Samples were investigated by x‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x‐ray spectroscopy (EDS), and electron back‐scattered diffraction (EBSD). Tribological properties were characterized by pin on disc tribometry and wear rates were determined by profilometry and abrasion testing. Solid/self‐lubrication in the TiC/C/Ni system was investigated by Raman and Auger mapping. A tribofilm, which undergoes a stress‐induced phase transformation from polycrystalline graphite to amorphous carbon, was formed during sliding in the TiC/C/Ni system that is responsible for low friction and wear. TiC additions help to further decrease wear. Stellite 21 was also found to exhibit acceptably low friction and wear properties arising from the presence of Cr23C6 in the matrix and work hardening of the cobalt and chromium during sliding.
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Date: December 2013
Creator: Kinkenon, Douglas
Partner: UNT Libraries

Stellite 6 Friction Changes Due to Aging and In-Service Testing

Description: For the past several years, researchers at the Idaho National Engineering and Environmental Laboratory, under the sponsorship of the U.S. Nuclear Regulatory Commission, have been investigating the ability of motor-operated valves to close or open when 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. The nuclear industry has developed methods to analytically predict 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 affects the disc-to-seat coefficient of friction. Specifically, does the accumulation of a surface film due to aging of these surfaces increase the coefficient of friction and if so, how much? This paper presents results of specimen tests addressing this issue with emphasis on the following: • The change in the friction coefficient of Stellite 6 as it ages and whether the friction reaches a plateau. • The effect periodic gate valve cycling due to in-service testing has on the friction coefficient. • The results of an independent review of the test methods, processes, and the results of the research to date. • The status of ongoing aging and friction testing.
Date: July 1, 2001
Creator: Watkins, John Clifford & DeWall, Kevin George
Partner: UNT Libraries Government Documents Department

Summary and Evaluation of NRC-Sponsored Stellite 6 Aging and Friction Tests

Description: This report describes four sets of tests sponsored by the U.S. Nuclear Regulatory Commission and conducted by the Idaho National Engineering and Environmental Laboratory. The tests support research addressing the need to provide assurance that motor-operated valves are able to perform their intended safety function, usually to open or close against specified (design basis) flow and pressure loads. One of the parameters that affects a gate valve's operability is the friction between the disc seats and the valve body seats. In most gate valves, these surfaces are hardfaced with Stellite 6, a cobalt-based alloy. The tests described in this report investigate the changes that occur in the friction as the Stellite 6 surfaces develop an oxide film as they age. Stellite 6 specimens were aged in a corrosion autoclave, the oxide films were examined and characterized, and the specimens were subjected to friction testing in a friction autoclave. A very thin oxide film formed after only a fe w days of natural aging. Even a very thin oxide film caused an increase in friction. The surface structure of the oxide film was dominated by a hard crystalline structure, such that the friction response was analogous to rubbing two pieces of sandpaper together. In the limited data provided by naturally aged specimens (78 days maximum exposure, very thin oxide films), the friction increased with greater aging time, approaching an as-yet-undetermined plateau. Although the thickness of the oxide film increased with greater aging time, the mechanical properties of the oxide film (larger granules with greater aging time) appeared to play a greater role in the friction response. Friction testing of specimens subjected to simulated in-service testing strokes at intervals during the aging process showed only a slight decrease in friction, compared to other specimens. Results from specimens subjected to accelerated aging were ...
Date: April 1, 1999
Creator: Watkins, J. C.; DeWall, K. G. & Bramwell, D.
Partner: UNT Libraries Government Documents Department

TESTING OF TMR SAND MANTIS FINAL REPORT

Description: Screening tests of Sand Mantis candidate materials selected for erosion resistance have been completed. The results of this testing identified that over a relatively short period of operation (<1 hour), measurable erosion will occur in each of the candidate zoom tube materials given equal operating exposure. Additionally, this testing has shown that erosion of the rubber discharge hose directly downstream of the vehicle could be expected to limit the service life of the discharge hose. On the basis of these test results, SRNL recommends the following; {lg_bullet} redesign of critical system components (e.g., zoom tube, discharge hose) should be conducted to improve system characteristics relative to erosion and capitalize on the results of this testing, {lg_bullet} continued efforts to deploy the Sand Mantis should include testing to better define and optimize operating parameters, and gain an understanding of system dynamics, {lg_bullet} discontinue wear testing with the selected materials pending redesign of critical system components (1st recommendation) and inclusion of other candidate materials. The final selection of additional candidate materials should be made following design changes, but might include a Stellite alloy or zirconia.
Date: June 12, 2007
Creator: Krementz, D & William Daugherty, W
Partner: UNT Libraries Government Documents Department

MACHINING TECHNIQUES AND PROCEDURES FOR URANIUM, GRAPHITE, TITANIUM, ZIRCONIUM, THORIUM, TANTALUM, BERYLLIUM, BISMUTH, LITHIUM, AND STELLITE

Description: Techniqnes are presented which are applicable in machining materinls such as U, graphite, Ti, Zr, Th, Ta, Be, Bi, Li, and stellite. Included in the general considerations are factors related to machinability of the materials, operating condition of the machines, and the condition of the cutting tools. In addition, industrial hygtene and safety aspects are examined. The techniques for each material are discussed in detail, the greatest attention being focused on uranium. (J.R.D.)
Date: November 1, 1952
Creator: Davis, C.
Partner: UNT Libraries Government Documents Department

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

Description: 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 failure of the valve body during welding ...
Date: December 1, 2001
Creator: CZAJKOWSKI,C. & BUTTERS,M.
Partner: UNT Libraries Government Documents Department

EVALUATION AND RECOMMENDATION OF SALTSTONE MIXER AUGER/PADDLES MATERIALS OF CONSTRUCTION FOR IMPROVED WEAR RESISTANCE

Description: Wear and corrosion testing were conducted to evaluate alternate materials of construction for the Saltstone mixer auger and paddles. These components have been degraded by wear from the slurry processed in the mixer. Material test options included PVD coatings (TiN, TiCN, and ZrN), weld overlays (Stellite 12 and Ultimet) and higher hardness steels and carbides (D2 and tungsten carbide). The corrosion testing demonstrated that the slurry is not detrimental to the current materials of construction or the new candidates. The ASTM G75 Miller wear test showed that the high hardness materials and the Stellite 12 weld overlay provide superior wear relative to the Astralloy and CF8M stainless steel, which are the current materials of construction, as well as the PVD coatings and Ultimet. The following recommendations are made for selecting new material options and improving the overall wear resistance of the Saltstone mixer components: A Stellite 12 weld overlay or higher hardness steel (with toughness equivalent to Astralloy) be used to improve the wear resistance of the Saltstone mixer paddles; other manufacturing specifications for the mixer need to be considered in this selection. The current use of the Stellite 12 weld overlay be evaluated so that coverage of the 316 auger can be optimized for improved wear resistance of the auger. The wear surfaces of the Saltstone mixer auger and paddles be evaluated so that laboratory data can be better correlated to actual service. The 2-inch Saltstone mixer prototype be used to verify material performance.
Date: August 15, 2012
Creator: Mickalonis, J. & Torres, R.
Partner: UNT Libraries Government Documents Department

Status of Stellite 6 friction testing

Description: 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.
Date: June 1, 1998
Creator: Watkins, J.C.; DeWall, K.G. & Weidenhamer, G.H.
Partner: UNT Libraries Government Documents Department

High-energy ion processing of materials for improved hardcoatings

Description: Research has been directed toward use of economically viable ion processing strategies for production and improvement of hardcoatings. Processing techniques were high-energy ion implantation and electron cyclotron resonance microwave plasma processing. Subject materials were boron suboxides, Ti-6Al-4V alloy, CoCrMo alloy (a Stellite{trademark}), and electroplated Cr. These materials may be regarded either as coatings themselves (which might be deposited by thermal spraying, plasma processing, etc.) or in some cases, as substrates whose surfaces can be improved. hardness and other properties in relation to process variables are reported.
Date: February 1, 1994
Creator: Williams, J.M.; Gorbatkin, S.M.; Rhoades, R.L.; Oliver, W.C.; Riester, L. & Tsui, T.Y.
Partner: UNT Libraries Government Documents Department

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, October 1994--December 1994

Description: Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. Initially, eleven weld overlay alloys were selected for erosion testing based upon a literature review. All eleven coatings were deposited on 1018 steel substrates using the plasma arc welding process. Ten samples from each coating were prepared for erosion testing. The coating deposition and sample preparation procedures were described in the second quarterly report. All selected coatings were erosion tested at 400{degree}C and their erosion resistance was evaluated by determining the steady state erosion rate. In addition, the microstructure of each coating was characterized before and after the erosion tests. The results of the tests are discussed in the third quarterly report. No correlations were found between room temperature hardness of the weld overlay coatings and their erosion resistance at elevated temperature. During the last quarter tensile tests were performed at 400{degree}C for the Ultimet, Inconel-625, 316L SS, C-22, and Stellite-6 wrought alloys. The erosion tests for these materials at 400{degree}C are in progress. The results of mechanical and erosion tests will be used to correlate mechanical properties of selected wrought alloys such as tensile toughness, ductility, strain hardening coefficient and yield strength to their erosion resistance at 400{degree}C. Also, the erosion behavior of the wrought alloys compared with similar weld alloys will be analyzed. The experimental procedure and results of the tensile tests are presented in this progress report.
Date: January 25, 1995
Creator: Levin, B. F.; Dupont, J. N. & Marder, A. R.
Partner: UNT Libraries Government Documents Department

Erosive wear of selected materials for fossil energy applications

Description: A number of materials have been evaluated to determine their erosion resistance for fossil energy applications. This is part of a larger program to study wear and corrosion at Albany Research Center. This paper will present the results for some of these materials, including FeAl, FeAl cermets, WC-Co cemented carbides, Si3N4-MoSi2, Si3N4, Stellite 6B, white cast irons and 440C steel. Trends in erosion rates due to material properties and erosive conditions will be presented. FeAl cermets performed well compared to the WC-Co cemented carbides. The interparticle spacing of the WC-Co cemented carbides correlated with the erosion rate. The erosion rate of the WC-Co cemented carbides decreased as the interparticle spacing decreased. It is important to realize that erosion resistance is not an intrinsic material property, but is a system response. A change in the wear environment can significantly alter the relative rankings of materials with respect to their wear rate. For example, at relatively low velocities, the carbides in the white cast irons are more erosion resistant than the matrix, while at higher velocities the matrix is more erosion resistant.
Date: January 1, 2001
Creator: Adler, Thomas A.; Rawers, James C.; Tylczak, Joseph H. & Hawk, Jeffrey A.
Partner: UNT Libraries Government Documents Department

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, January 1995--March 1995

Description: Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. During the last two quarters tensile tests were performed at 400{degrees}C for the Ultimet, Inconel-625, 316L SS, C-22, and Stellite-6 wrought alloys. Also, the erosion tests for these materials at 400{degrees}C were completed. The results of mechanical and erosion tests are used to correlate mechanical properties of selected wrought alloys such as tensile toughness, ductility, strain hardening coefficient and yield strength to their erosion resistance at 400{degrees}C. Preliminary results of correlations between erosion resistance of wrought alloys at 400{degrees}C and their mechanical properties are presented in this progress report.
Date: April 25, 1995
Creator: Levin, B. F.; Dupont, J. N. & Marder, A. R.
Partner: UNT Libraries Government Documents Department

Self-welding evaluation of reactor materials in flowing sodium

Description: An experimental study was made of the self-welding of various combinations of FBR materials (304 ss, Inconel 718, A286, Stellite 156, and Stellite 6) in sodium at 800 to 1100$sup 0$F for time periods up to 6 months and contact stresses of 2 to 148 ksi. Stresses required to separate the surfaces were determined. Self-welding was observed only at temperatures of 1050$sup 0$F and above, with the breakaway force being less than 5 ksi. (DLC)
Date: January 1, 1975
Creator: Chang, J. Y.; Flagella, P. N. & Schrock, S. L.
Partner: UNT Libraries Government Documents Department