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Fundamental studies of stress distributions and stress relaxation in oxide scales on high temperature alloys. Progress report

Description: The high temperature X-ray diffraction system developed for this program is being used to measure the strains which develop during oxidation. This is being applied to Ni/NiO and Cr/Cr{sub 2}O{sub 3}. Our work suggests tat the oxide and metal crystalline texture, anisotropic elastic modulus and anisotropic thermal expansion can have a pronounced effect on strain state of these systems. Acoustic emission is being used to study oxide scale failure (fracture) during oxidation. AE data from 304 stainless steel are being used to develop a statistical model of fracture process. Strength of metal/scale interface is an important property that has been difficult to quantify. Using Nano-indentation and scratch techniques developed for characterizing thin film interfaces, an effort has begun to measure the fracture toughness of the metal/scale interface. Mathematical modelling of origin and time evolution of growth stresses is an extension and improvement of previous models. The current effort employs a more sophisticated stress analysis and expands the scope to include other stress relaxation process. The interaction between the modeling studies and the X-ray diffraction measurements provides a natural credibility check to both efforts.
Date: June 1, 1992
Creator: Shores, D. A.; Stout, J. H. & Gerberich, W. W.
Partner: UNT Libraries Government Documents Department

Vapor deposition of copper on stainless steel 304L

Description: Y-12 Plant is seeking to minimize the generation of hazardous wastes in its operations. The standard procedure for electroplating a thin layer of copper on type 304L stainless steel requires several aqueous pretreatment steps which generate Resource Conservation and Recovery Act (RCRA) hazardous wastes. We have evaluated a more environmentally acceptable procedure. Copper was vacuum deposited onto 304L coupons under differing deposition conditions and properties of coatings produced, including microstructure and adhesive strength, were examined. Results indicated that a noncolumnar, fine grain copper coating with high adhesion can be produced using this environmentally more acceptable approach.
Date: August 17, 1993
Creator: Vasofsky, R. W.
Partner: UNT Libraries Government Documents Department

Tritium and decay helium effects on the fracture toughness properties of types 316L, 304L and 21Cr-6Ni-9Mn stainless steels

Description: J-integral fracture mechanics techniques and electron microscopy observations were used to investigate the effects of tritium and its radioactive decay product, {sup 3}He, on Types 316L, 304L and 21Cr-6Ni-9Mn stainless steels. Tritium-exposed-and-aged steels had lower fracture-toughness values and shallower sloped crack-growth-resistance curves than unexposed steels. Both fracture-toughness parameters decreased with increasing concentrations of {sup 3}He. The fracture-toughness reductions were accompanied by a change in fracture mode from microvoid-nucleation-and-growth processes in control samples to grain-and-twin-boundary fracture in tritium-charged-and-aged samples. Type 316L stainless steel had the highest fracture-toughness values and Type 21Cr-6Ni-9Mn had the lowest. Samples containing {sup 3}He but degassed of tritium had fracture toughness properties that were similar to uncharged samples. The results indicate that helium bubbles enhance the embrittlement effects of hydrogen by affecting the deformation properties and by increasing localized hydrogen concentrations through trapping effects.
Date: October 1, 1994
Creator: Morgan, M. J. & Tosten, M. H
Partner: UNT Libraries Government Documents Department

Welding tritium exposed stainless steel

Description: Stainless steels that are exposed to tritium become unweldable by conventional methods due to buildup of decay helium within the metal matrix. With longer service lives expected for tritium containment systems, methods for welding on tritium exposed material will become important for repair or modification of the systems. Solid-state resistance welding and low-penetration overlay welding have been shown to mitigate helium embrittlement cracking in tritium exposed 304 stainless steel. These processes can also be used on stainless steel containing helium from neutron irradiation, such as occurs in nuclear reactors.
Date: November 1, 1994
Creator: Kanne, W. R. Jr.
Partner: UNT Libraries Government Documents Department

Fundamental studies of stress distributions and stress relaxation in oxide scales on high temperature alloys. [Final progress report]

Description: This report summarizes a three-year study of stresses arising in the oxide scale and underlying metal during high temperature oxidation and of scale cracking. In-situ XRD was developed to measure strains during oxidation over 1000{degrees}C on pure metals. Acoustic emission was used to observe scale fracture during isothermal oxidation and cooling, and statistical analysis was used to infer mechanical aspects of cracking. A microscratch technique was used to measure the fracture toughness of scale/metal interface. A theoretical model was evaluated for the development and relaxation of stresses in scale and metal substrate during oxidation.
Date: June 1, 1993
Creator: Shores, D. A.; Stout, J. H. & Gerberich, W. W.
Partner: UNT Libraries Government Documents Department

Thermal analysis of the horizontal shipping container for normal conditions of transport with solar insolation

Description: A thermal analysis of the horizontal shipping container (HSC) was performed to determine the temperatures at the outer surface of the inner container during normal conditions of transport with incident solar radiation. There are two methods by which this analysis can be performed: (1) it can be run as a steady-state problem where it is assumed that the incident solar radiation is applied to the package 24 hours per day, or (2) it can be run as a cyclic transient problem where the incident solar radiation is applied for 12 hours per day and the other 12 hours there is assumed to be no incident solar radiation. The steady-state method was initially attempted, but the temperatures determined from this analysis were judged to be significantly higher than one would find in the cyclic case. Thus, it was deemed necessary to perform a transient analysis to determine a more realistic temperature distribution within the HSC during normal conditions of transport. The heat transfer code HEATING 7.1 was used to perform these calculations. HEATING 7.1 is a heat conduction code capable of handling radiation, convection (forced and natural), and heat flux boundary conditions. Heat generation within a material is also possible with HEATING 7.1 but was not used in any of the models presented here. The models used here are one-dimensional in the radial direction.
Date: April 2, 1993
Creator: Stumpfl, E.; Feldman, M. R. & Anderson, J. C.
Partner: UNT Libraries Government Documents Department

Characterizing pre-polished Type 304L stainless steel

Description: Prepolished Type 304L stainless steel surfaces are being specified for replacement of some equipment in the 221-H Canyon Building at the Savannah River Site. A prepolished stainless steel surface picks up less contamination than a hot-rolled and pickled surface and is easier to decontaminate; therefore, less waste is generated. Surface-characterization techniques and specification for a prepolished surface were developed to ensure that prepolished items being obtained were properly electropolished. The use of this technology has resulted in obtaining prepolished items with an improved surface finish.
Date: October 1, 1994
Creator: Hsu, R. H.; Summer, M. E. & Rankin, W. N.
Partner: UNT Libraries Government Documents Department

Characterization of the deformation and annealing of 304L stainless steel. Final report

Description: Stainless steel, type 304L, was deformed at room temperature using the two processes of semi-piercing and cold-rolling and then annealed at various temperatures and times. The three metallurgical areas of work hardening, age hardening, and anneal softening were observed and characterized using metallography techniques of macrohardness, optical and transmission electron microscopy, and X-ray diffraction.
Date: August 1, 1994
Creator: Smith, W. H.
Partner: UNT Libraries Government Documents Department

Resistance upset welding for vessel fabrication

Description: Solid-state resistance upset welding has been successfully applied to fabrication of small vessels. The process has advantages compared with the fusion welding processes currently used to join the two halves of such vessels. These advantages result from the improved metallurgical properties of the weld zone and the simplicity of the welding process. Spherical and cylindrical shapes have been fabricated using the upset welding process. Nondestructive and destructive tests have shown excellent weld strength. Storage tests have demonstrated long term compatibility of the welds for cylindrical parts made from 304L stainless steel that have been in storage for eight years. Spherical vessels and reinforced desip vessels made from forged 21-6-9 stainless steel have been prepared for storage.
Date: October 1, 1992
Creator: Kanne, W. R. Jr.
Partner: UNT Libraries Government Documents Department

Analysis of crack initiation and growth in the high level vibration test at Tadotsu

Description: The High Level Vibration Test data are used to assess the accuracy and usefulness of current engineering methodologies for predicting crack initiation and growth in a cast stainless steel pipe elbow under complex, large amplitude loading. The data were obtained by testing at room temperature a large scale modified model of one loop of a PWR primary coolant system at the Tadotsu Engineering Laboratory in Japan. Fatigue crack initiation time is reasonably predicted by applying a modified local strain approach (Coffin-Mason-Goodman equation) in conjunction with Miner`s rule of cumulative damage. Three fracture mechanics methodologies are applied to investigate the crack growth behavior observed in the hot leg of the model. These are: the {Delta}K methodology (Paris law), {Delta}J concepts and a recently developed limit load stress-range criterion. The report includes a discussion on the pros and cons of the analysis involved in each of the methods, the role played by the key parameters influencing the formulation and a comparison of the results with the actual crack growth behavior observed in the vibration test program. Some conclusions and recommendations for improvement of the methodologies are also provided.
Date: August 1, 1993
Creator: Kassir, M. K.; Park, Y. J.; Hofmayer, C. H.; Bandyopadhyay, K. K. & Shteyngart, S.
Partner: UNT Libraries Government Documents Department

Feasibility of a novel approach for fast, economical determination of radiation damage in nuclear reactor cores. [Annual report, November 1, 1992--October 30, 1993]

Description: Progress was made in the following areas: radioinduced segregation (modeling and experiment), deformation of irradiated microstructures, stress corrosion cracking of irradiated microstructures, and development of an apparatus to determine the role of deformation on the radiation microstructure in-situ. Materials used were based on Ni-Cr-Fe and 304L.
Date: July 7, 1993
Creator: Was, G. S.
Partner: UNT Libraries Government Documents Department

Rapid heating tensile testing update: 304L stainless steel

Description: In stainless steel equipment exposed to tritium, embrittlement is thought to involve interactions between internal He and the complex triaxial stress state that arises when necking starts. Recent efforts have been directed at determining He concentration thresholds for this effect in several austenitic stainless steels. This report describes results of tests on 304L stainless steel containing low He-3 contents. 304L ss containing 0.47 and 4.1 appM He-3 tested at 803--814{degrees}C had lower tensile properties than uncharged samples. Mechanical properties were not affected by 0.47 appM at 615{degrees}C but ductility was severely decreased at 810{degrees}C.
Date: August 1, 1993
Creator: Mosley, W. C.
Partner: UNT Libraries Government Documents Department

Microscopic evaluation of low-temperature embrittlement in Type 308 stainless steel welds

Description: Effect of aging of type 308 stainless steel weld metal from 400 to 550C on microstructure was examined. Microstructural development was correlated with earlier results on mechanical properties that showed the ferrite-containing welds were prone to severe embrittlement when aged in this temperature range. The embrittlement was manifested by an increase in the ductile-brittle transition temperature and a drop in the upper-shelf energy. It was found that although the embrittlement over this aging temperature range was comparable, the microstructural changes that were responsible for the embrittlement were different at different temperatures. Embrittlement was caused by a combination of spinodal decomposition of ferrite, precipitation of M{sub 23}C{sub 6} carbide at the ferrite/austenite interface, and G-phase precipitation within the ferrite. Sigma phase formation at 550C may also be a contributing factor to the embrittlement.
Date: September 1, 1993
Creator: Vitek, J. M.; David, S. A. & Alexander, D. J.
Partner: UNT Libraries Government Documents Department

Transmission electron microscopy study of thick copper-304 stainless steel multilayers

Description: Thick (10 to 25 {mu}m), free-standing, equal layer thickness, Copper(Cu)-304 Stainless Steel(SS) multilayer foils, having periods of 1 to 100 nm, synthesized by magnetron sputter deposition, were examined by plan view and cross-sectional transmission electron microscopy. Multilayer growth morphology, individual layer structure and crystallographic phase orientation relationships were characterized in this study. Electron Energy Loss filtered imaging of a 20 nm period multilayer cross-section was also performed and showed that nickel had diffused into the Cu layers from the SS during synthesis. X-ray powder diffraction scans were performed and analyzed. A pure deposit of 304SS was synthesized and had a metastable BCC structure. Multilayer samples having periods of 20 nm were found to have a coherent layered Cu(FCC)SS(FCC) structure. At larger periods (50 & 100 nm) a bimodal Cu(FCC)-SS(FCC & BCC) structure was formed. These observations show that the 304SS will grow with a metastable BCC structure when sputter deposited. When layered with Cu(FCC) the 304SS has its equilibrium FCC structure at layer thicknesses up to 10nm as a result of epitaxy with the copper. At larger SS layer thicknesses the SS appears to locally transform to the metastable BCC structure during synthesis, refining the grain structure of the depositing SS layer and the subsequent Cu layer. This transformation significantly increases the strength of the larger period multilayer.
Date: June 8, 1993
Creator: Wall, M. A.; Barbee, T. W. Jr. & Weihs, T.
Partner: UNT Libraries Government Documents Department

Documentation for initial testing and inspections of Beneficial Uses Shipping System (BUSS) Cask

Description: The purpose of this report is to compile data generated during the initial tests and inspections of the Beneficial Uses Shipping System (BUSS) Cask. In addition, this report will verify that the testing criteria identified in section 8.1 of the BUSS Cask Safety Analysis Report for Packaging (SARP) was met. The BUSS Cask Model R-1 is a type B shipping container used for shipment of radioactive cesium-137 and strontium-90 capsules to Waste Encapsulation and Storage Facility (WESF). The BUSS Cask body and lid are each one-piece forgings fabricated from ASTM A473, Type 304 stainless steel. The primary purpose of the BUSS Cask is to provide shielding and confinement as well as impact, puncture, and thermal protection for the capsules under both normal and accident conditions. Chapter 8 of the BUSS Cask SARP requires several acceptance tests and inspections, each intended to evaluate the performance of different components of the BUSS Cask system, to be performed before its first use. The results of the tests and inspections required are included in this document.
Date: August 25, 1994
Creator: Lundeen, J. E.
Partner: UNT Libraries Government Documents Department

FFTF reactor immersion heaters. Revision 1

Description: This specification establishes requirements for design, testing, and quality assurance for electric heaters that will be used to maintain primary Sodium temperature in the Fast Test Facility (FFTF) reactor vessel. The Test Specification (WHC-SD-FF-SDS-003) has been revised to Rev. 1. This change modifies the fabrication of approximately 25 feet of the subject heater using ceramic insulators over the heater lead wire rather than compressed magnesium oxide. Also, 304 or 316 stainless steel can be used for the heater sheath. This change should simplify fabrication and improve the heater operational reliability.
Date: August 26, 1994
Creator: Romrell, D. M.
Partner: UNT Libraries Government Documents Department

Laser materials processing applications at Lawrence Livermore National Laboratory

Description: High power and high radiance laser technologies developed at Lawrence Livermore National Laboratory (LLNL) such as copper-vapor lasers, solid-state slab lasers, dye lasers, harmonic wavelength conversion of these lasers, and fiber optic delivery systems show great promise for material processing tasks. Evaluation of models suggests significant potential for tenfold increases in welding, cutting, and drilling performance, as well as capability for applications in emerging technologies such as micromachining, surface treatment, and stereolithography. The goals of this program are to develop low-cost, reliable and maintainable industrial laser systems. Chains of copper lasers currently operate at more than 1.5 kW output and achieve mean time between failures of more than 1,000 hours. The beam quality of copper vapor lasers is approximately three times the diffraction limit. Dye lasers have near diffraction limited beam quality at greater than 1.0 kW. diode laser pumped, Nd:YAG slab lasers are also being developed at LLNL. Current designs achieve powers of greater than 1.0 kW and projected beam quality is in the two to five times diffraction limited range. Results from cutting and drilling studies in titanium and stainless steel alloys show that cuts and holes with extremely fine features can be made with dye and copper-vapor lasers. High radiance beams produce low distortion and small heat-affected zones. The authors have accomplished very high aspect ratio holes in drilling tests (> 60:1) and features with micron scale (5-50 {mu}m) sizes. Other, traditionally more difficult, materials such as copper, aluminum and ceramics will soon be studied in detail.
Date: February 25, 1993
Creator: Hargrove, R. S.; Dragon, E. P.; Hackel, R. P.; Kautz, D. D. & Warner, B. E.
Partner: UNT Libraries Government Documents Department

Cutting and drilling studies using high power visible lasers

Description: High power and radiance laser technologies developed at Lawrence Livermore National Laboratory such as copper-vapor and dye lasers show great promise for material processing tasks. Evaluation of models suggests significant increases in welding, cutting, and drilling capabilities, as well as applications in emerging technologies such as micromachining, surface treatment, and stereolithography. Copper lasers currently operate at 1.8 kW output at approximately three times the diffraction limit and achieve mean time between failures of more than 1,000 hours. Dye lasers have near diffraction limited beam quality at greater than 1.0 kW. Results from cutting and drilling studies in titanium and stainless steel alloys show that cuts and holes with extremely fine features can be made with dye and copper-vapor lasers. High radiance beams produce low distortion and small heat-affected zones. The authors have accomplished very high aspect ratios (> 60:1) and features with micron scale (5-50 {mu}m) sizes. The paper gives a description of the equipment; discusses cutting theory; and gives experimental results of cutting and drilling studies on Ti-6Al-4V and 304 stainless steel.
Date: May 27, 1993
Creator: Kautz, D. D.; Dragon, E. P.; Werve, M. E.; Hargrove, R. S. & Warner, B. E.
Partner: UNT Libraries Government Documents Department

Foil support structure for large electron guns

Description: This paper describes a novel support structure for a vacuum diode used to pump a gaseous laser with an electron beam. Conventional support structures are designed to hold a foil flat and rigid. This new structure takes advantage of the significantly greater strength of metals in pure tension, utilizing curved shapes for both foil and support structure. The shape of the foil is comparable to the skin of a balloon, and the shape of the support structures is comparable to the cables of a suspension bridge. This design allows a significant reduction in foil thickness and support structure mass, resulting in a lower electron-beam loss between diode and laser gas. In addition, the foil is pre-formed in the support structure at pressures higher than operating pressure. Therefore, the foil is operated far from the yield point. Increased reliability is anticipated.
Date: August 1, 1993
Creator: Brucker, J. P. & Rose, E. A.
Partner: UNT Libraries Government Documents Department

Inelastic analysis acceptance criteria for radioactive material transportation containers

Description: The design criteria currently used in the design of radioactive material (RAM) transportation containers are taken from the ASME Boiler and Pressure Vessel Code (ASME, 1992). These load-based criteria are ideally suited for pressure vessels where the loading is quasistatic and all stresses are in equilibrium with externally applied loads. For impact events, the use of load-based criteria is less supportable. Impact events tend to be energy controlled, and thus, energy-based acceptance criteria would appear to be more appropriate. Determination of an ideal design criteria depends on what behavior is desired. Currently there is not a design criteria for inelastic analysis for RAM nation packages that is accepted by the regulatory agencies. This lack of acceptance criteria is one of the major factors in limiting the use of inelastic analysis. In this paper inelastic analysis acceptance criteria based on stress and strain-energy density will be compared for two stainless steel test units subjected to impacts onto an unyielding target. Two different material models are considered for the inelastic analysis, a bilinear fit of the stress-strain curve and a power law hardening model that very closely follows the stress-strain curve. It is the purpose of this paper to stimulate discussion and research into the area of strain-energy density based inelastic analysis acceptance criteria.
Date: June 1, 1993
Creator: Ammerman, D. J. & Ludwigsen, J. S.
Partner: UNT Libraries Government Documents Department

Investigation of residual stresses in a multipass weld in 1 in. stainless steel plate

Description: Residual stresses and strains were measured in two welded 25-mm thick plates of type 304 stainless steel by the neutron diffraction. The filler metal was type 308 stainless steel and the weld zone had a two phase microstructure in which the austenitic phase lattice parameter differs from the base metal. In these circumstances stain-free samples were taken from the weld zone area for analysis of the lattice parameters and ferrite content using neutron powder diffraction. Corrections for lattice parameter variation were applied permitting the calculation of residual strains and stresses in weld zone, heat affected zone (HAZ) and base metal. One of the two welds was examined without stress relief and the other was given a stress relief treatment consisting of vibration at a frequency below the resonant condition dudng welding. In both plates the largest residual stress component (longitudinal) is found in the fusion zone near the boundary between the weld zone and the heat affected zone. This longitudinal component is 400 {plus_minus} 50 MPa in tension. The normal stresses are generally close to zero although large fluctuations are found in the weld zone. The transverse stresses are as high as 200 MPa in the weld zone and decrease to 50 MPa {plus_minus} 40 MPa. The lattice parameter variation was equivalent to 5 {times} l0{minus}4 compressive strain and the ferrite content approached 9 percent at the center of the weld zone. Variations in residual stresses with thickness through the base metal plate were small. The treated plate and untreated plate showed nearly identical patterns of stress distribution. Differences in the measured stresses between vibratory-stress-relief treated and untreated plates fall within error bars of the stress determination in these particular 25 mm thick 300-type stainless steel plates.
Date: June 1, 1994
Creator: Spooner, S.; Fernandez Baca, J. A.; David, S. A.; Hubbard, C. R.; Holden, T. M. & Root, J. H.
Partner: UNT Libraries Government Documents Department

Summary of work on coatings and claddings for fossil energy applications

Description: A summary of efforts to examine coatings and cladding materials for high-strength austenitic steels is provided. Chromized coatings on 17--14CuMo stainless steel and a modified type 316 (HT-UPS) stainless steel were investigated. Claddings included alloy 671, 690, and an iron-aluminide intermetallic alloy. Structural alloys that were clad included type 304 stainless steel, modified type 316 stainless steel, and modified alloy 800H. The capability of producing co-extruded tubing of the experimental alloys was demonstrated.
Date: May 1, 1993
Creator: Swindeman, R. W.
Partner: UNT Libraries Government Documents Department

Residual stresses in a multi-pass weld in an austenitic stainless steel plate before and after thermal stress relief

Description: Changes in residual stresses due to thermal stress relief were determined in a welded 1/2 in. thick 304 stainless steel plate from two residual stress maps determined with the neutron diffraction technique. The 304 stainless plate was made from two 6 {times} 12 {times} 1/2 in. pieces joined along the length by a gas tungsten arc welding process. Multi-pass welds were made with a semiautomatic welding machine employing cold-wire feed of type 308 stainless steel filler alloy. The thermal stress relief treatment consisted of heating to 1150 F, holding for one hour at temperature and then air cooling. Strain components were measured along the weld direction (longitudinal), perpendicular to the weld line in the plate (transverse), and normal to the plate. Measurements were confined to the plane bisecting the weld at the center of the plate. The strain components were converted to stresses assuming that the measured strains were along the principal axes of the strain tensor. Parameters used in the calculation were E=224 GPa and v=0.25. As-welded longitudinal stresses are compressive in the base metal and become strongly tensile through the heat affected zone and into the fusion zone. The transverse stresses follow the longitudinal trend but with a lower magnitude while the normal stresses are small throughout. The stress relief treatment reduced the magnitudes of all the stresses. In the weld zone the longitudinal stress was lowered by 30% and the spatial range of residual stresses was reduced as well.
Date: June 1, 1994
Creator: Spooner, S.; Wang, X. L.; Hubbard, C. R. & David, S. A.
Partner: UNT Libraries Government Documents Department

Long term laboratory corrosion monitoring of calcine bin set materials exposed to zirconia calcine

Description: Corrosion testing of Type 1025 carbon steel, 405, 304, 304L, 316L, and 347 stainless steels, and 6061-T6 aluminum were conducted in synthetic zirconia calcine to model long term corrosion performance of bin set material. Testing was conducted over a period of 17 years. The existing calcine bin set {number_sign}1 is constructed of Type 405 stainless steel, 2 through 4 are constructed of Type 304 stainless steel and 5 through 7 are constructed of Type 304L stainless steel. The highest rate observed for Type 304L stainless steel was 8.1 {times} 10{sup {minus}7} inches per month. This would equal a wall thickness loss of about 5 mils after 500 years of storage. Currently, the established schedule for removal of corrosion test coupons from the calcine storage bins is at the end of the 10th, 100th, 250th, and 450th year of solid storage service. Very low corrosion rates and metal oxide data determined from the long term laboratory test, in conjunction with corrosion rates from the coupon assessment of the second bin set, indicate this schedule should be revised from 10 years to 50 years for the first assessment.
Date: June 1, 1994
Creator: Dirk, W. J.
Partner: UNT Libraries Government Documents Department