17-4 stainless steel for 17-4 include components which require high hardness and/or corrosion resistance at temperatures of up to . Specific applications for 17-4 include the petroleum and chemical industries, as well as use in aircraft parts. 17-4 stainless steel SAE type 630 stainless steel (more commonly known as 17-4; also known as UNS 17400) is a grade of martensitic precipitation-hardened stainless steel. It contains approximately 15–17.5% (17) chromium and 3–5% (4) nickel, as well as 3–5% copper. 17-4 can be heat treated to high levels of strength and hardness, and features corrosion resistance and machinability comparable to austenitic 304 stainless. Being martensitic,
Stainless steel throughout the paper making process. For example, duplex stainless steels are being used in digesters to convert wood chips into wood pulp. 6% Mo superaustenitics are used in the bleach plant and Type 316 is used extensively in the paper machine. Stainless steels are used extensively in these industries for their corrosion resistance to both aqueous, gaseous and high temperature environments, their mechanical properties at all temperatures from cryogenic to the very high, and occasionally for other special physical properties. Austenitic (300 series) stainless steel, in particular Type 304 and 316, is the material of choice for the food and