Radiation-induced mechanical property changes reviewed include hardening, fracture toughness, embrittlement, swelling, creep, and fatigue. Radiation-induced metallurgical changes include radiation-induced segregation, dislocation loop formation, phase stability, and transmutation. This chapter reviews the physical and mechanical behavior of stainless steels in the reactor environment. Was, Shigeharu Ukai, in Structural Alloys for Nuclear Energy Applications, 2019 AbstractĪustenitic stainless steels are one of the most important alloy systems used as structural components in current and future nuclear reactor systems. The numerous surface finishes that can be applied to stainless steel, from mirror to matte, do not degrade over time and keep their appearance as well as their functionality. But, like the noble metals, stainless steel can also be used simply for its esthetic appeal. Nordberg and Bjorklund (1992) contains numerous papers on the many industrial uses of stainless steel. Uniquely, they are equally useful for uses up to 800 ☌, where they find wide use in heat exchangers, boilers, turbines, furnaces, and automotive exhaust systems, where the formability of ferritics or their creep resistance is insufficient. Since austenitics are tough even to liquid helium temperatures they are widely used in all cryogenic applications. The high strength of cold-worked austenitic stainless steel makes it the predominant material for use in transit cars, but also in springs, seatbelt anchors, and knife blades. Automotive filter bodies, pen cartridges, cooking pots, and disk drive parts are examples of the latter. Stretch-formed parts, such as sinks, are an example of the use of the more unstable austenitic grades, while the highly stable grades are used for deeply drawn parts or for components where low magnetic permeability is sought. Sometimes formability becomes an equally important a requirement as corrosion resistance. Specifying stainless steel can eliminate such problems at a small premium to the overall cost. Initial cost is often a poor measure of a material, such as in the case of concrete reinforcing bars, where the entire structure is jeopardized by corrosion of a minor component. Ease of welding and fabrication are important in these applications, but stainless is used simply because it is the most economical material that can do the job. The food, pharmaceutical, chemical, pulp and paper, and petrochemical industries depend heavily on austenitic stainless steels because their corrosion resistance yields low maintenance, lack of product contamination, high cleanability, and long life. Because their initial cost is often higher than that of alternative materials, their popularity is based on their minimization of cost over the entire life cycle of their use. Michler, in Reference Module in Materials Science and Materials Engineering, 2016 10 ApplicationsĪustenitic stainless steels are used for domestic, industrial, transport, and architectural products based primarily on their corrosion resistance but also for their formability, their strength, and their properties at extreme temperatures. Martensite gives steel great hardness, but it also reduces its toughness and makes it brittle, so few steels are fully hardened.T. Martensitic steels are low carbon steels built around the Type 410 composition of iron, 12% chromium, and 0.12% carbon. Martensitic: The characteristic orthorhombic martensite microstructure was first observed by German microscopist Adolf Martens around 1890.Ferritic steel is less ductile than austenitic steel and is not hardenable by heat treatment. These steels contain iron and chromium, based on the Type 430 composition of 17% chromium. Ferritic:Ferritic steels have ferrite (body-centered cubic crystal) as their main phase.Type 304 surgical stainless steel is austenitic steel containing 18-20% chromium and 8-10% nickel. The most familiar stainless steel is probably Type 304, sometimes called T304 or simply 304. Austenitic steels are not hardenable by heat treatment. These are alloys containing chromium and nickel (sometimes manganese and nitrogen), structured around the Type 302 composition of iron, 18% chromium, and 8% nickel.
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