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Description: A compilation is given of corrosion data for approximates 570 samples that were exposed prior to Dec. 31, 1961, to flowing sodium in six sodium mass transfer test loops. The loops and samples comprised 316 stainless steel, 21/4 Cr--1 Mo steel, and/or 5 Cr-- 1/2 Mo-- 1/2 Ti steel. Analysis reports are also presented for all the test runs reported. (D.L.C.)
Date: May 1, 1962
Partner: UNT Libraries Government Documents Department


Description: A steam generator, wherein the boiler, steam drum, and superheater are integrated into one single unit, requires the welding of a transition joint between the 2 1/4% Cr-1% Mo steel of the steam drum and the type 316 stainless steel of the superheater. A practicable procedure was developed for the welding of this transition joint and the properties of the weld were evaluated by mechanical testing and metallurgical evaluation. After evaluating the technical aspects of the project and their relation to the fabrication of the generator, it was considered desirable to overlay the welding edge of the 2 1/4% Cr-1% Mo steel with a suitable austenitic weld metul which would subsequently be welded to the type 316 stainless steel of the superheater. Austenitic stainless steel and high-nickel alloy weld metals were evaluated for the overlay; whereas only austenitic stainless steel weld metals were evaluated for the final weld joining the components. It was concluded that type 309 stainless steel weld metal deposited automatically by the submergedarc process is completely satisfactory for cladding the 2 1/4% Cr-1% Mo base metal and for making the final transition weld joining the steam drum and superheater sections of the generator. Supplementary mechanical tests, metallographic examinations, and hardness surveys further attested to the adequacy of the quality of the transition joint resulting from the procedures developed by this program. A detailed fabrication and thermal treatment specification is included for the welding of a transition joint between
Date: August 15, 1960
Partner: UNT Libraries Government Documents Department

Tensile and Charpy impact properties of irradiated reduced-activation ferritic steels

Description: Tensile tests were conducted on 8 reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on steels irradiated to 26-29 dpa. Irradiation was in Fast Flux Test Facility at 365 C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15- 17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20,000 h at 365 C. Thermal aging had little effect on tensile properties or ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in upper-shelf energy (USE). After 7 dpa, strength increased (hardened) and then remained relatively unchanged through 26-29 dpa (ie, strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness (increased DBTT, decreased USE) remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels had the most irradiation resistance.
Date: October 1, 1996
Creator: Klueh, R.L. & Alexander, D.J.
Partner: UNT Libraries Government Documents Department

Microstructural Stability and Oxidation Resistance of 9-12 Chromium Steels at Elevated Temperatures

Description: Various martensitic 9-12 Cr steels are utilized currently in fossil fuel powered energy plants for their good elevated temperature properties such as creep strength, steam side oxidation resistance, fire side corrosion resistance, and thermal fatigue resistance. Need for further improvements on the properties of 9-12 Cr steels for higher temperature (>600oC) use is driven by the environmental concerns (i.e., improve efficiency to reduce emissions and fossil fuel consumption). In this paper, we will discuss the results of the research done to explore new subsitutional solute solution and precipitate hardening mechanisms for improved strength of 9-12 Cr martensitic steels. Stability of the phases present in the steels will be evaluated for various temperature and time exposures. A comparison of microstructural properties of the experimental steels and commercial steels will also be presented. <br><br> The influence of a Ce surface treatment on oxidation behavior of a commercial (P91) and several experimental steels containing 9 to 12 weight percent Cr was examined at 650ºC in flowing dry and moist air. The oxidation behavior of all the alloys without the Ce modification was significantly degraded by the presence of moisture in the air during testing. For instance the weight gain for P91 was two orders of magnitude greater in moist air than in dry air. This was accompanied by a change in oxide scale from the formation of Cr-based scales in dry air to the formation of Fe-based scales in moist air. The Ce surface treatment was very effective in improving the oxidation resistance of the experimental steels in both moist and dry air. For instance, after exposure to moist air at 650ºC for 2000 hours, an experimental alloy with the cerium surface modification had a weight gain three orders of magnitude lower than the alloy without the Ce modification and two orders of ...
Date: May 1, 2006
Creator: Dogan, O.N.; Alman, D.E.; Jablonski, P.D. & Hawk, J.A.
Partner: UNT Libraries Government Documents Department


Description: The preliminary work done by Westinghouse on properties of materials suitable for the in-pile testing facility was reviewed. Information was collected on a selected list of promising materials in the following classificrtions: alloy steels, chromium steels, precipitation-hardening stainless steels, and superalloys. On the basis of the information obtained from Westinghouse, from the literature survey, from Battelle files, and from visits to producers, it is recommended that Phase II of the program be confined to Inconel X hot rolled and aged, AM-350 subzero cooled and tempered, and Discaloy solution treated and aged. (auth)
Date: September 16, 1957
Creator: Simmons, W.F.; Boyd, W.K.; Sopher, R.P. & Lyon, F.H.
Partner: UNT Libraries Government Documents Department

A comparison of low-chromium and high-chromium reduced-activation steels for fusion applications

Description: Ferritic steels have been considered candidate structural materials for first wall and blanket structures for fusion power plants since the late 1970s. The first steels considered in the United States were the conventional Cr-Mo steels Sandvik HT9 (nominally 12Cr-1Mo-0.25V-0.5W-0.5Ni-0.2C, here designated l2Cr-1MoVW), modified 9Cr-1Mo steel (9Cr-1Mo-0.2V-0.06Nb-0. IC, designated 9Cr-1MoVNb) and, to a lesser extent, 2 1/4Cr-1Mo steel (2.25Cr-Mo-0.1C). All compositions are in wt. %. The normalized-and-tempered 9 and 12Cr steels had a tempered martensite microstructure, and the normalized-and-tempered 2 1/4 Cr steel had a tempered bainite microstructure. This report describes chromium steels tested in normalized and tempered conditions. Miniature tensile and Charpy specimens were tested.
Date: November 1, 1996
Creator: Klueh, R.L.; Maziasz, P.J. & Alexander, D.J.
Partner: UNT Libraries Government Documents Department

Development of a comprehensive weld process model

Description: This cooperative research and development agreement (CRADA) between Concurrent Technologies Corporation (CTC) and Lockheed Martin Energy Systems (LMES) combines CTC`s expertise in the welding area and that of LMES to develop computer models and simulation software for welding processes. This development is of significant impact to the industry, including materials producers and fabricators. The main thrust of the research effort was to develop a comprehensive welding simulation methodology. A substantial amount of work has been done by several researchers to numerically model several welding processes. The primary drawback of most of the existing models is the lack of sound linkages between the mechanistic aspects (e.g., heat transfer, fluid flow, and residual stress) and the metallurgical aspects (e.g., microstructure development and control). A comprehensive numerical model which can be used to elucidate the effect of welding parameters/conditions on the temperature distribution, weld pool shape and size, solidification behavior, and microstructure development, as well as stresses and distortion, does not exist. It was therefore imperative to develop a comprehensive model which would predict all of the above phenomena during welding. The CRADA built upon an already existing three-dimensional (3-D) welding simulation model which was developed by LMES which is capable of predicting weld pool shape and the temperature history in 3-d single-pass welds. However, the model does not account for multipass welds, microstructural evolution, distortion and residual stresses. Additionally, the model requires large resources of computing time, which limits its use for practical applications. To overcome this, CTC and LMES have developed through this CRADA the comprehensive welding simulation model described above.
Date: May 1997
Creator: Radhakrishnan, B.; Zacharia, T. & Paul, A.
Partner: UNT Libraries Government Documents Department

Fracture behavior of bainitic chromium-tungsten and chromium-molybdenum steels

Description: Bainitic microstructures formed during continuous cooling of low-carbon alloy steels often appear different from classical upper and lower bainite developed by isothermal transformation. The kind of non-classical bainite produced during transformation determines the fracture behavior in a Charpy impact test. Quenching and normalizing treatments of a 3Cr-1.5Mo-0.25V-0.lC steel gave two different bainitic microstructures: a carbide-free acicular structure formed during quenching and a granular bainite formed during normalizing. The superior impact toughness of the quenched steel over the normalized steel was attributed to the difference in microstructure. A similar observation on microstructure was made for a 2.25Cr-2W-0.1C and a 2.25Cr-2W-0.25V-0.lC steel. These observations were used to develop new Cr-W steels with improved strength and impact toughness.
Date: December 31, 1994
Creator: Klueh, R.L.; Alexander, D.J. & Maziasz, P.J.
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