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Welding of High Chromium Steels

Description: A brief description is given of different groups of high chromium steels (rustless iron and stainless steels) according to their composition and more generally accepted names. The welding procedure for a given group will be much the same regardless of the slight variations in chemical composition which may exist within a certain group. Information is given for the tensile properties (yield point and ultimate strength) of metal sheets and welds before and after annealing on coupons one and one-half inches wide.
Date: June 1928
Creator: Miller, W. B.
Partner: UNT Libraries Government Documents Department

Consideration of History Dependent Damage in Creep Crack Growth

Description: The effects of load history on the creep crack growth process are discussed. There are three aspects of this problem which are considered: (i) the constitutive response of materials undergoing history dependent creep straining, (ii) the corresponding crack growth behavior including a discussion of fracture parameters capable of predicting the response, and (iii) experimental evidence of the importance of history dependent response. Finally, numerical studies which use the constitutive model and fracture theory of (i) and (ii) respectively are used to examine the experimental results developed in (iii).
Date: 1992
Creator: Brust, F. W., Jr.; Krishnaswamy, P. & Majumdar, B. S.
Partner: UNT Libraries Government Documents Department

Modeling of the formation of microporosity in alloys

Description: A complete mathematical model, consisting of a continuum model and a gas evolution model, was established for the prediction of shrinkage- and gas-caused porosity in castings. The model allows simultaneous calculation of transient temperature, velocity, pressure, and porosity distributions in a solidifying casting. Fluid flow caused by both natural convection and solidification contraction, as well as change of global domain due to shrinkage, were considered. A parametric study was performed to investigate the effects of various solidification variables in the formation of microporosity, including the use of chilling, initial gas content, characteristics of heat transfer between the casting and the mold, casting size, and riser height. It was found that a low initial gas content in the molten metal and casting conditions that facilitate solidification-rate decrease the formation of microporosity. The calculated porosity distribution in 1% Cr-steel alloys compares favorably with published experimental data.
Date: July 1, 1993
Creator: Chang, F. C. & Tsai, H. L.
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


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

Analytical representation of mechanical properties data for 2 1/4 Cr--1 Mo steel

Description: An extensive program has been underway at the Oak Ridge National Laboratory (ORNL) for the last five years to develop analytical representations for various mechanical properties of 2 1/4 Cr--1 Mo steel. This program includes an evaluation of tensile, creep, fatigue, creep-fatigue, crack growth, and toughness data for this material. Data were collected from a variety of sources and stored in an existing computerized Data Storage and Retrieval System (DSRS) to facilitate analysis. Most of these evaluations have been used to develop data pages for the Nuclear Systems Materials Handbook (NSMH).
Date: January 1, 1978
Creator: Booker, M.K.
Partner: UNT Libraries Government Documents Department


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

Microstructural development in low activation ferritic alloys irradiated to 200 dpa at 420{degree}C

Description: Density change and microstructural development are reported for nine low activation ferritic steels covering the range 2.3 to 12 Cr with varying additions of V and/or W for hardening and up to 6.5 Mn for austenite stability. Specimens were examined following irradiation in FFTF/MOTA at 4200{degree}C to a dose exceeding 200 dpa. Void swelling was found, but the swelling remained at 5% or below, with the worst case in an alloy of 9Cr-2Mn-1WV. The carbide structure pinning Martensite lath boundaries remains in place.
Date: December 1, 1993
Creator: Gelles, D. S.
Partner: UNT Libraries Government Documents Department

Flow lines and microscopic elemental inhomogeneities in austenitic stainless steels

Description: Flow lines in mechanically formed austenitic stainless steels are known to influence fracture behavior. Enhancement of flow lines by chemical etching is evidence of elemental inhomogeneity. This paper presents the results of electron microprobe analyses to determine the nature of flow lines in three austenitic stainless steels: 21Cr-6Ni-9Mn, 304L, and 19Ni-18Cr.
Date: January 1, 1982
Creator: Mosley, Jr, W C
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

Evaluation of hydrogen embrittlement in Cr-Mo pressure vessel steels. Topical report No. 1

Description: Commercial 2 1/4 Cr-1 Mo low strength steel specimens have been tested to measure their susceptibility to hydrogen embrittlement in an environment of H/sub 2/S at 50 psig. It was found that two factors, viz. (1) the plane stress zones on the crack front in compact tension specimens, and (2) incubation time effects, seriously confounded measurements on these steels when tested by conventional rising load experiments. Because of the incubation time effect, K/sub or/ (the stress intensity at which cracking starts in a rising load test) is a loading rate dependent variable and is usually significantly greater than the arrest stress intensity, K/sub arr/ in a bolt loaded test. K/sub arr/ must therefore be used as a measure of hydrogen resistance. The incubation time has been significantly reduced by cyclicly loading in the environment to initiate the crack and K/sub arr/ has been measured by holding the specimen in constant displacement immediately after crack initiation. The plane stress problem has been eliminated by deeply side grooving the compact tension (CT) specimens. As an example of the importance of these effects a 3T CT smooth sided specimen was compared with a side grooved 2T CT specimen of the same steel. Whereas the K/sub or/ value for the smooth 3T was approximately 150 ksi in/sup 1/2/ the K/sub arr/ value for the side notched 2T was approximately 20 ksi in/sup 1/2/. A study of the effect of strength level is included.
Date: August 24, 1980
Creator: Shaw, B.J. & Johnson, E.W.
Partner: UNT Libraries Government Documents Department

Microstructural stability of 21-6-9 stainless steel

Description: Two experiments were designed to better define parameters for thermomechanical processing of 21-6-9 stainless steel. This steel is one of the nitrogen-strengthened chromium, manganese, and nickel austenitic stainless steels having mechanical properties that can be improved by a combination of plastic deformation and heat treatments. By heat-treating coupons, the time-temperature relationship of the precipitate phase, and the solutionizing, recrystallizing, and stress-relieving temperature ranges in 21-6-9 were established. Secondly, mechanical properties and microstructure as a function of percent deformation and stress-relieving temperature are reported.
Date: May 18, 1978
Creator: Krenzer, R.W. & Sanderson, E.C.
Partner: UNT Libraries Government Documents Department

Hydrogen attack of steel. Final report

Description: Hydrogen attack in commercial quenched and tempered 2 1/4 Cr - 1 Mo steel was studied. The sensitive dilatometer developed in the past was used. The Nelson curve for 2 1/4 Cr - 1 Mo steel has been updated, and both the curve and rationale for the curve are included in an appendix. (DLC)
Date: March 1, 1984
Creator: Shewmon, P.G.
Partner: UNT Libraries Government Documents Department

Effect of austenitizing temperature upon the microstructure and mechanical properties of experimental Fe/Cr/C and Fe/Cr/C/Ti steels

Description: Increasing the austenitizing temperature from 870/sup 0/C to 1100/sup 0/C and higher can increase the fracture toughness, K/sub Ic/, of common high strength structural steels from 50 to 100% with no loss in strength. However, the ductility (% reduction in area from a tensile test) decreases by as much as a factor of 3, and the Charpy impact energy either decreases or remains constant. The trend of increasing fracture toughness and decreasing Charpy impact energy appears to be inconsistent, but has been rationalized by considering the interaction of the stress field as a function of notch root radius and the microstructure. The present study investigates the as-quenched strength and toughness of simple Fe/Cr/C alloys with and without titanium as a function of austenitizing temperature. For the ternary Fe/Cr/C alloys the results are consistent with earlier investigations, but the fracture toughness does not change with increasing austenitizing temperatures after 0.2 wt % Ti is added. The titanium forms carbides (TiC) that did not dissolve, providing a roughly constant number of crack nucleation sites, and preventing austenite grain growth up to 1100/sup 0/C. The differences in mechanical behavior, particularly the rounded notch toughness, are discussed and explained in terms of the microstructural characteristics of the alloys.
Date: June 1, 1978
Creator: Carlson, M.
Partner: UNT Libraries Government Documents Department

Fabrication of modified 9 Cr-1 Mo steel test article for exposure in sodium components test loop at Energy Technology Engineering Center

Description: The fabrication, inspection, shipment, and mechanical properties of a modified 9 Cr-1 steel test article for exposure in the Sodium Components Test Loop (SCTL) at the Energy Technology Engineering Center (ETEC) are described. The test article delivered consisted of modified 9 Cr-1 Mo steel pipe 232 mm in diameter by 12.7-mm wall by 610 mm long. This pipe was safe ended with type 304L stainless steel spool pieces 152 mm long on each end. The joint between modified 9 Cr-1 Mo and type 304L was made with ERNiCr-3 filler wire. The entire test article was postweld heat treated 1 h at 732/sup 0/C and ultrasonically inspected before use. Radiography was used to inspect the welds between modified 9 Cr-1 Mo and type 304L stainless steel. The test article was delivered to ETEC on schedule on October 4, 1982. After delivery of the test article, we fabricated an additional piece of the same dimensions by the same procedure for archive purposes, mechanical property testing, and comparison with the actual test article after test. A part of this archive piece also provided a nondestructive examination standard for in-service inspection for ETEC. The archive specimen has already been subjected to tensile and creep testing, microstructural evaluation, and thermal aging for 2000 h at 510/sup 0/C. The test article has completed a year of operation in the SCTL. We expect to remove this pipe after three years of operation for testing and examination.
Date: April 1, 1984
Creator: Sikka, V.K.; Goodwin, G.M.; King, J.F. & Cook, K.V.
Partner: UNT Libraries Government Documents Department

Study to optimize Cr-Mo steels to resist hydrogen and temper embrittlement. Quarterly report No. 6, November 15, 1979-February 15, 1980

Description: A modified test technique has been developed in this program to overcome difficulties in assessing the hydrogen embrittlement susceptibility of low strength 2 1/4 Cr-1 Mo steels. One steel sample was tempered to a range of strength levels and evaluated using the new technique. The results, showing a lower strength level for which hydrogen embrittlement susceptibility can be assessed in a 446 KPa H/sub 2/S environment, are presented in this report. A review of the restructuring of the program is also given.
Date: July 28, 1980
Creator: Shaw, B.J.
Partner: UNT Libraries Government Documents Department