17-4 stainless steel 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, 17-4 is magnetic. 17-4 is capable of being hardened up to approximately 44 Rc when heat treated to condition H900. Overaging (aging beyond the peak strength condition) improves resistance to stress corrosion cracking. Uses
Sharon Steel Corporation the Sharon Steel Hoop Corporation in 1933. Aided by improvement in business conditions, the Sharon Steel continued to expand its sales volume and to make further improvements in production facilities during the thirties. Equipment for the production of terne and tin coating was added, a new product under the trade name of “Galvanite” was produced, and other specialties were added to the company's line of products. New electric furnaces were installed at the Lowellville Works to make stainless steel ingots to be converted into stainless steel strip on the Sharon finishing mills. A great change came about in the company