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The crystallography of fatigue crack initiation in Incoloy-908 and A-286 steel

Description: Fatigue crack initiation in the austenitic Fe-Ni superalloys Incoloy-908 and A-286 is examined using local crystallographic orientation measurements. Results are consistent with sharp transgranular initiation and propagation occurring almost exclusively on {l_brace}111{r_brace} planes in Incoloy-908 but on a variety of low index planes in A-286. This difference is attributed to the influence of the semicoherent grain boundary {eta} phase in A-286. Initiation in each alloy occurred both intergranularly and transgranularly and was often associated with blocky surface oxide and carbide inclusions. Taylor factor and resolved shear stress and strain crack initiation hypotheses were tested, but despite an inconclusive suggestion of a minimum required {l_brace}111{r_brace} shear stress, none of the hypotheses were found to convincingly describe preferred initiation sites, even within the subsets of transgranular cracks apparently free from the influence of surface inclusions. Subsurface inclusions are thought to play a significant role in crack initiation. These materials have applications for use in structural conduit for high field superconducting magnets designed for fusion energy use.
Date: December 1, 1996
Creator: Krenn, C.R.
Partner: UNT Libraries Government Documents Department

Growth of small fatigue cracks in Incoloy-908

Description: Incoloy-908 was designed as a structural alloy for the conduit of cable-in-conduit superconductors. The conduit is a thin-wall tube that encloses superconducting cables. Since the conduit may be as thin as 3 to 12 mm in thickness and is subject to cyclic loads, fatigue crack growth behavior at liquid helium temperature, especially in the small crack regime, is a critical issue for magnet design. Because it is difficult to perform small fatigue crack propagation tests at 4.2 K, we have studied mechanisms of small crack propagation at room temperature and 77 K, and use the results to propose a feasible method for estimating small crack propagation at 4.2 K.
Date: July 1, 1993
Creator: Mei, Z.; Krenn, C. & Morris, J. W. Jr.
Partner: UNT Libraries Government Documents Department

Containment barrier metals for high-level waste packages in a Tuff repository

Description: The Nevada Nuclear Waste Storage Investigations (NNWSI) Waste Package project is part of the US Department of Energy`s Civilian Radioactive Waste Management (CRWM) Program. The NNWSI project is working towards the development of multibarriered packages for the disposal of spent fuel and high-level waste in tuff in the unsaturated zone at Yucca Mountain at the Nevada Test Site (NTS). The final engineered barrier system design may be composed of a waste form, canister, overpack, borehole liner, packing, and the near field host rock, or some combination thereof. Lawrence Livermore National Laboratory`s (LLNL) role is to design, model, and test the waste package subsystem for the tuff repository. At the present stage of development of the nuclear waste management program at LLNL, the detailed requirements for the waste package design are not yet firmly established. In spite of these uncertainties as to the detailed package requirements, we have begun the conceptual design stage. By conceptual design, we mean design based on our best assessment of present and future regulatory requirements. We anticipate that changes will occur as the detailed requirements for waste package design are finalized. 17 references, 4 figures, 10 tables.
Date: October 12, 1983
Creator: Russell, E.W.; McCright, R.D. & O`Neal, W.C.
Partner: UNT Libraries Government Documents Department

Rapid heating tensile tests of solution-annealed Incoloy 903 charged with hydrogen and tritium

Description: Rapid heating tensile tests from room temperature to above 1000{degree}C have been performed on specimens of solution-annealed Incoloy 903 charged with hydrogen and tritium. Absorbed hydrogen had very little effect on tensile properties. Internal helium from radioactive decay of absorbed tritium drastically decreased ductility above 700{degree}C.
Date: December 31, 1990
Creator: Mosley, W. C.
Partner: UNT Libraries Government Documents Department

Exposure of high-temperature alloys in carbonaceous gas atmospheres

Description: Light and scanning electron microscopy were used to evaluate changes resulting from exposure of eight commercial high temperature alloys in carbonaceous atmospheres. Samples were exposed in CO, CH$sub 4$, or CO/CH$sub 4$ mixtures up to 900$sup 0$C and 6.2 MPa. All alloys were actively attacked. Surface finish and preoxidation influenced the extent of corrosion. Reduction of NiO, giving a high surface concentration of Ni, promoted catalytic decomposition of CH$sub 4$. Further work is indicated before the performance of these alloys may be ranked with confidence. (auth)
Date: September 1, 1975
Creator: Goldberg, A. & Perkins, A.J.
Partner: UNT Libraries Government Documents Department

Corrosion of nickel alloys in nuclear fuel reprocessing

Description: Corrosion studies were made of high Ni alloys in process solutions which will be encountered during reprocessing of fuel from Shippingport PWR Core 2, seeds 1 and 2. The alloys were Hastelloy C-276 and C-4, Inconel 625, Incoloy 825, Hastelloy S, Hastelloy G, and Inconel 671. Effects of process variables were studied. Welded Hastelloy C-276 vessels were constructed and tested. (DLC)
Date: January 1, 1975
Creator: Paige, B.E.
Partner: UNT Libraries Government Documents Department

Investigation of the cryogenic mechanical properties of low thermal-expansion superalloys

Description: Four Fe-based superalloys, JBK-75, Incoloy 903, Incoloy 905, and Incoloy 909 were evaluated as tube materials for ICCS Nb/sub 3/Sn superconductors. Evaluation consisted of 4-K tensile and elastic-plastic fracture-toughness testing, and a microstructural characterization of unwelded and autogenously gas-tungsten-arc welded sheet given a simulated postweld processing treatment of 15% cold reduction by rolling followed by a Nb/sub 3/Sn-reaction heat treatment of 96 hours at 700/sup 0/C plus 48 hours at 730/sup 0/C. Results indicate that JBK-75 and Incoloy 903 showed satisfactory combinations of strength and toughness for ICCS tube use requiring long Nb/sub 3/Sn-reaction heat treatments. Incoloy 905 welds and 909 showed unacceptable fracture toughness. Results are discussed in terms of microstructural changes caused by the extended Nb/sub 3/Sn-reaction heat treatment.
Date: July 30, 1985
Creator: Summers, L.T. & Dalder, E.N.C.
Partner: UNT Libraries Government Documents Department

Use of generalized regression models for the analysis of stress-rupture data

Description: The design of components for operation in an elevated-temperature environment often requires a detailed consideration of the creep and creep-rupture properties of the construction materials involved. Techniques for the analysis and extrapolation of creep data have been widely discussed. The paper presents a generalized regression approach to the analysis of such data. This approach has been applied to multiple heat data sets for types 304 and 316 austenitic stainless steel, ferritic 2/sup 1///sub 4/ Cr-1 Mo steel, and the high-nickel austenitic alloy 800H. Analyses of data for single heats of several materials are also presented. All results appear good. The techniques presented represent a simple yet flexible and powerful means for the analysis and extrapolation of creep and creep-rupture data.
Date: January 1, 1978
Creator: Booker, M.K.
Partner: UNT Libraries Government Documents Department

Creep-fatigue effects in structural materials used in advanced nuclear power generating systems

Description: Various aspects of time-dependent fatigue behavior of a number of structural alloys in use or planned for use in advanced nuclear power generating systems are reviewed. Materials included are types 304 and 316 stainless steel, Fe-2 1/4 Cr-1 Mo steel, and alloy 800H. Examples of environmental effects, including both chemical and physical interaction, are presented for a number of environments. The environments discussed are high-purity liquid sodium, high vacuum, air, impure helium, and irradiation damage, including internal helium bubble generation.
Date: January 1, 1980
Creator: Brinkman, C.R.
Partner: UNT Libraries Government Documents Department

Effect of aging and cold working on the high-temperature low-cycle fatigue behavior of alloy 800H: Part II continuous cyclic loading. [Aging 4000 and 8000 hr at 538 to 760/sup 0/C]

Description: The individual and combined effects of cold working (5 and 10 pct) and aging (4000 and 8000 h in the temperature range 538 to 760/sup 0/C) on the high-temperature low-cycle fatigue behavior of alloy 800H have been investigated. The specimens were tested at the aging temperatures. Both the saturation stress range and the fatigue life were found to be history dependent. A history-independent hardening mechanism, dynamic strain aging, was found to operate over the temperature range approx. 450 to 650/sup 0/C and to be maximized at approx. 550/sup 0/C. It is speculated that carbon is responsible for this dynamic strain aging. Finally, at temperatures above 538/sup 0/C the Coffin-Manson plots indicate the possible existence of a history-independent softening mechanism.
Date: October 1, 1979
Creator: Villagrana, R.E.; Kaae, J.L. & Ellis, J.R.
Partner: UNT Libraries Government Documents Department

Oxidation of selected alloys during 25,000 h in superheated steam at 482 and 538/sup 0/C

Description: The corrosion of several ferritic and austenitic materials in flowing superheated steam at 482 and 538/sup 0/C (900 and 1000/sup 0/F) were studied. Results obtained during the first 12,000 h of the test were presented previously. Results obtained during the first 25,000 h are summarized. The test specimens are mounted in a nonrecirculating loop that receives steam from the superheater circuit of a fossil-fired power plant. At both temperatures all materials exhibited parabolic oxidation kinetics during the first year and subsequently have oxidized at low constant rates. The ferritic steels containing 2 1/4 and 9% Cr have oxidized at about the same rates, averaging 4.2 and 8.6 ..mu..m/year (0.17 and 0.34 mils/year) at 482 and 538/sup 0/C, respectively, after the first year. Sandvik HT-9 (11.4% Cr) has corroded at slightly lower rates. Annealed and Cold-worked surfaces of these alloys have exhibited identical behavior. At 482/sup 0/C all materials have retained their corrosion products completely, but at 538/sup 0/C some began experiencing exfoliation after 12,000 h. Data suggest that a high silicon content in the alloy minimizes exfoliation. Cold-worked surfaces of alloy 800 are corroding at lower rates than annealed and pickled ones, but in both cases the rates are very low. Alloy 800 specimens that had been intergranularly corroded before exposure to steam are oxidizing at much higher rates, but intergranular penetration has not progressed. Type 304 stainless steel is corroding nonuniformly, but the attack rates are low at both temperatures. Alloy 617 is corroding at the lowest rate of any material in the loop; even after 25,000 h surface films are thin enough to show interference colors.
Date: March 1, 1980
Creator: Griess, J.C. & Maxwell, W.A.
Partner: UNT Libraries Government Documents Department

Fluidized bed waste heat recovery system. Annual report, 1 October 1981-31 March 1983

Description: An agreement was reached in July 1982 with the Aluminum Company of America regarding the Massena operations in New York. Since that agreement, a specification has been published which characterizes the waste stream and includes ALCOA, DOE and Aerojet design requirements. Installation of the test unit has been engineered in preliminary form by ALCOA in close liaison with Aerojet and details are being established. A subcontract has been awarded for the design and fabrication of the fluid bed heat exchanger. Initial thermal analyses are complete and a preliminary arrangement layout has been started. Materials corrosion tests were conducted by Oak Ridge National Laboratory on samples of fluid bed heat exchanger materials under the range of temperatures expected. Samples included carbon steel, stainless steels and Incoloy. Test atmospheres included hydrogen chloride and chlorine corrosive species. A study was completed of the research and development which would be necessary to raise the gas inlet temperature rating of the heat exchanger above 1100/sup 0/F. This study has been formalized and submitted in a topical report and discussions are ongoing regarding an activity (Task VI) added to the present contract to conduct high temperature R and D work.
Date: January 1, 1983
Creator: Williams, H. W. & Unmack, K. E.
Partner: UNT Libraries Government Documents Department

Progress toward analytical description of the creep strain-time behavior of engineering alloys

Description: Elevated-temperature design methods in the United States often require a comprehensive description of the properties of the construction materials. These descriptions include representations for creep strain-time behavior as a function of stress, temperature, and material variability. Work conducted at this laboratory in the past five years toward the development of analytical techniques to derive such representations is summarized. Results for several common elevated-temperature structural materials are presented to illustrate the techniques.
Date: January 1, 1980
Creator: Booker, M.K.
Partner: UNT Libraries Government Documents Department

Rapid heating tensile tests of solution-annealed Incoloy 903 charged with hydrogen and tritium

Description: Rapid heating tensile tests from room temperature to above 1000{degree}C have been performed on specimens of solution-annealed Incoloy 903 charged with hydrogen and tritium. Absorbed hydrogen had very little effect on tensile properties. Internal helium from radioactive decay of absorbed tritium drastically decreased ductility above 700{degree}C.
Date: January 1, 1990
Creator: Mosley, W.C.
Partner: UNT Libraries Government Documents Department

Development of a procedure for estimating the high cycle fatigue strength of some high temperature structural alloys

Description: The generation of strain controlled fatigue data, for the standard strain rate of 4 x 10/sup -3/ sec/sup -1/, presents a problem when the cycles to failure exceed 10/sup 5/ because of the prohibitively long test times involved. In an attempt to circumvent this difficulty an evaluation has been made of a test procedure involving a fast cycling rate (40 Hz) and load controlled conditions. The validity of this procedure for extending current fatigue curves from 10/sup 5/ to 10/sup 8/ cycles and beyond, hinges upon the selection of an appropriate effective strain value, since the strain usually changes rapidly during the early stage of fatigue. Results from annealed 2 1/4 Cr-1 Mo, type 304 stainless steel, Incoloy 800H and Hastelloy X, tested over a wide range of temperatures, show that the strain measured N/sub f/2 is a reasonable estimate since it gives an excellent correlation between the strain and load controlled tests in the 10/sup 5/ cycle range where the data overlap. It seems clear that the differences in cycling rate and early stress-strain history for the two tests do not significantly affect the correlation. It may, therefore, be concluded that such load control test procedures may be used as a valid fast way for extending currently available fatigue curves from 10/sup 5/ to 10/sup 8/ cycles, and beyond.
Date: January 1, 1979
Creator: Soo, P. & Chow, J.G.Y.
Partner: UNT Libraries Government Documents Department

Atmospheric fluidized bed combustion technology test unit for industrial cogeneration plants

Description: The AFBC Technology Test Unit Program will develop the technology for a fluidized bed coal combustion system to provide a source of high temperature air for process heating and power generation with gas turbines in industrial plants. The gas turbine has the advantages of a higher ratio of electric power output to exhaust heat load and a higher exhaust temperature than do steam turbines in cogeneration applications. This type of system appears to be attractive for development, particularly for installations in the range of 5 to 50 MW(e). The conceptual design of the Technology Test Unit has been completed. The 1.8 m (6 ft)-square combustor has a bed depth of 0.6 m (2 ft) which has been designed for atmospheric pressure and 900/sup 0/C (1650/sup 0/F) to produce a heat output of about 1500 kW(t) (5 x 10/sup 6/ Btu/hr). A number of furnace design firms have been invited to submit their own designs for the combustor, from which a final selection will be made. Development and testing have been conducted in the areas of fluidization, heat transfer, tube corrosion and coal feeding. New results on heat transfer, tube corrosion and coal feeding are presented in this paper. The TTU program was authorized by ERDA in June 1977, and will require about two years for design, procurement and installation followed by two years of testing.
Date: January 1, 1977
Creator: Fraas, A.P. & Holcomb, R.S.
Partner: UNT Libraries Government Documents Department

Austenitic stainless steel-to-ferritic steel transition joint welding for elevated temperature service

Description: Transition weld joints between ferritic steels and austenitic stainless steels are required for fossil-fired power plants and proposed nuclear plants. The experience with these dissimilar-metal transition joints has been generally satisfactory, but an increasing number of failures of these joints is occurring prematurely in service. These concerns with transition joint service history prompted a program to develop more reliable joints for application in proposed nuclear power plants.
Date: January 1, 1978
Creator: King, J.F.; Goodwin, G.M. & Slaughter, G.M.
Partner: UNT Libraries Government Documents Department

Metallographic evaluation of the reactions between boronated graphite and Fe-Ni-Cr alloys

Description: The compatibility of boronated graphite with alloy 800H and type 316 stainless steel was evaluated metallographically after exposures at 700 and 810/sup 0/C for up to 10,000 h. At 700/sup 0/C, the principal reaction with both alloys was limited oxidation. At 810/sup 0/C, three types of reactions were observed: localized reactions at sites where the B/sub 4/C particles were in contact with the alloys' surfaces, intergranular penetration (much more prevalent for alloy 800H), and carburization.
Date: January 1, 1984
Creator: Tortorelli, P.F.; Mayotte, J.R.; Henson, T.J. & DeVan, J.H.
Partner: UNT Libraries Government Documents Department

Low-Cost Solar Array Project. Task I. Silicon material: investigation of the hydrogenation of SiCl/sub 4/. Seventh quarterly report

Description: Research and development work on the hydrochlorination of SiCl/sub 4/ and m.g. silicon metal to SiHCl/sub 3/ is reported. Activities include a series of experiments to study the life of the Si mass bed. The effect of prolonged reaction on the rate of the hydrochlorination reaction was studied, and a material balance on the reaction was made. A corrosion study was made on Incoloy 800 as the selected material of construction for the hydrochlorination reactor in the Union Carbide EPSDU. (WHK)
Date: January 12, 1981
Creator: Mui, J.Y.P
Partner: UNT Libraries Government Documents Department

Steam generator materials performance in high temperature gas-cooled reactors

Description: This paper reviews the materials technology aspects of steam generators for HTGRs which feature a graphite-moderated, uranium-thorium, all-ceramic core and utilizes high-pressure helium as the primary coolant. The steam generators are exposed to gas-side temperatures approaching 760/sup 0/C and produce superheated steam at 538/sup 0/C and 16.5 MPa (2400 psi). The prototype Peach Bottom I 40-MW(e) HTGR was operated for 1349 EFPD over 7 years. Examination after decommissioning of the U-tube steam generators and other components showed the steam generators to be in very satisfactory condition. The 330-MW(e) Fort St. Vrain HTGR, now in the final stages of startup, has achieved 70% power and generated more than 1.5 x 10/sup 6/ MWh of electricity. The steam generators in this reactor are once-through units of helical configuration, requiring a number of new materials factors including creep-fatigue and water chemistry control. Current designs of larger HTGRs also feature steam generators of helical once-through design. Materials issues that are important in these designs include detailed consideration of time-dependent behavior of both base metals and welds, as required by current American Society of Mechanical Engineers (ASME) Code rules, evaluation of bimetallic weld behavior, evaluation of the properties of large forgings, etc.
Date: November 1, 1980
Creator: Chafey, J.E. & Roberts, D.I.
Partner: UNT Libraries Government Documents Department

Relationship between carburization and zero-applied-stress creep dilation in Alloy 800H and Hastelloy X. [HTGR]

Description: Typical HTGR candidate alloys can carburize when exposed to simulated service environments. The carbon concentration gradients so formed give rise to internal stresses which could cause dilation. Studies performed with Hastelloy X and Alloy 800H showed that dilations of up to almost 1% can occur at 1000/sup 0/C when carbon pickup is high. Dilation was normally observed only when the carbon increase was >1000 ..mu..g/cm/sup 2/ and ceased when the diffusing carbon reached the center of the specimen.
Date: January 1, 1981
Creator: Inouye, H. & Rittenhouse, P.L.
Partner: UNT Libraries Government Documents Department

Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures

Description: Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X.
Date: January 1, 1981
Creator: Swindeman, R.W. & Brinkman, C.R.
Partner: UNT Libraries Government Documents Department

Correlation of high cycle and low cycle fatigue data for some HTGR structural metals

Description: An analytical procedure has been evaluated to determine whether low and high cycle fatigue testing techniques may be correlated in the 10/sup 5/ cycle region where the data overlap. The procedure, which is based on the use of cyclic stress-strain curves to convert high cycle fatigue stresses to equivalent strains, is shown to be acceptable for Incoloy 800H, Hastelloy X, Type 304 stainless steel and 2 1/4 Cr--1Mo steel in the range of temperature for which data are available.
Date: January 1, 1978
Creator: Soo, P. & Chow, J.G.Y.
Partner: UNT Libraries Government Documents Department