Hydrogen environment embrittlement of stable austenitic steels

This report may be updated and revised periodically in response to the needs of the technical community; up-to-date versions can be requested from the editors at the address given below or downloaded at http://www.ca.sandia.gov/matlsTechRef/ . The content of this report will also be incorporated into a Sandia National Laboratory report (SAND2008-1163); the most recent version can be obtained from the link above. The success of this reference depends upon feedback from the technical community; please forward your comments, suggestions, criticisms and relevant public-domain data to the authors C. San Marchi (cwsanma@sandia.gov) and/or B.P. Somerday (bpsomer@sandia.gov) at: Sandia National Laboratories Technical Reference on Hydrogen Compatibility of Materials MS-9404 7011 East Ave Livermore CA 94550.

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Technical Reference on Hydrogen Compatibility of Materials

Influence of macro segregation on hydrogen environment embrittlement of SUS 316L stainless steel

The behavior of four austenitic stainless steel alloys containing bulk hydrogen contents up to 50 ppm by weight (0.28 at. pct) has been determined in sustained load and in slow strain rate tensile tests. Tests of these same alloys were also made in hydrogen gas. AISI 301 and two compositions of AISI 304 of different austenite stability showed typical three stage crack propagation regimes under sustained load. AISI 310S did not. The slow crack growthvs stress intensity relation was quite sensitive to hydrogen content above a minimum value and also sensitive to austenite stability. It was shown that hydrogen contents up to 40 wt ppm had no influence on the austenite stability at tensile elongations up to 60 pct. Fractographic and phase analysis results are presented, and a model for crack propagation is discussed.

Effects of hydrogen concentration on slow crack growth in stainless steels

Hydrogen embrittlement of catholically hydrogen-precharged 304L austenitic stainless steel: Effect of plastic pre-strain

This handbook compiles data on the effects of hydrogen on the mechanical properties of stainless steels and discusses this data within the context of current understanding of hydrogen compatibility of metals. All of the tabulated data derives from continuing studies of hydrogen effects on materials that have been conducted at the Savannah River Laboratory over the past fifteen years. Supplementary data from other sources are included in the discussion. Austenitic, ferritic, martensitic, and precipitation hardenable stainless steels have been studied. Damage caused by helium generated from decay of tritium is a distinctive effect that occurs in addition to the hydrogen isotopes protium and deuterium. The handbook defines the scope of our current knowledge of hydrogen effects in stainless steels and serves as a guide to selection of stainless steels for service in hydrogen.

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Hydrogen compatibility handbook for stainless steels

Tensile specimens of iron-chromium-nickel base alloys were broken in either a hydrogen environment or in air following thermal charging with hydrogen Fracture surfaces were examined by scanning electron microscopy Fracture morphology of hydrogen-embrittled specimens was characterized by: changed dimple size, twin-boundary parting, transgranular cleavage, and intergranular separation The nature and extent of the fracture mode changes induced by hydrogen varied systematically with alloy composition and test temperature Initial microstructure developed during deformation processing and heat treating had a secondary influence on fracture mode

Fractography of hydrogen-embrittled iron-chromium-nickel alloys

High level waste at SRS is stored in carbon steel tanks constructed during the period 1951 to 1981. This waste contains radionuclides that decay by alpha, beta, or gamma emission or are spontaneous neutronsources. Thus, a low intensity radiation field is generated that is capable of causing displacement damage to the carbon steel. The potential for degradation of mechanical properties was evaluated by comparing the estimated displacement damage with published data relating changes in Charpy V-notch (CVN) impact energy to neutron exposure. Experimental radiation data was available for three of the four grades of carbonsteel from which the tanks were constructed and is applicable to all four steels. Estimates of displacement damage arising from gamma and neutron radiation have been made based on the radionuclide contents for high level waste that are cited in the Safety Analysis Report (SAR) for the Liquid Waste Handling Facilities in the 200-Area. Alpha and beta emissions do not penetrate carbon steel to a sufficient depth to affect the bulk properties of the tank walls but may aggravate corrosion processes. The damage estimates take into account the source of the waste (F- or H-Area), the several types of tank service, and assume wateras an attenuatingmore » medium. Estimates of displacement damage are conservative because they are based on the highest levels of radionuclide contents reported in the SAR and continuous replenishment of the radionuclides.« less

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Potential radiation damage: Storage tanks for liquid radioactive waste

Hot-rolled uranium plate exhibited a pronounced directionality in mechanical properties which was reduced but not eliminated by beta transformation. Results of tensile, bend, impact and hardness tests made at room temperature are summarized for both hotrolled and beta-transfomned uranium plate. Significant differences in mechanical properties existed between ten lots of uranium plate processed under similar conditions. Composition and processing data were inadequate to assign causes for the variations. (auth)

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G.R. Jr. Caskey

Papers

Hydrogen compatibility handbook for stainless steels

Fractography of hydrogen-embrittled iron-chromium-nickel alloys

Potential radiation damage: Storage tanks for liquid radioactive waste

Mechanical properties of uranium plate

Surface effects on tritium diffusion in materials in a radiation environment