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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


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

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

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

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