This specification covers the chemical requirements for wrought stainless steels used for the manufacture of surgical instruments. Classes of stainless steels covered here are Class 3 (austenitic stainless steel), Class 4 (martensitic stainless steel), Class 5 (precipitation hardening stainless steel), and Class 6 (ferritic stainless steel). The data contained in this specification, such as typical hardness values, common heat treating cycles, and examples of selected stainless steels that have been used for surgical instruments, are provided for reference only. Mechanical property, heat treatment, hardness, and all other requirements except for chemical composition, are governed by the appropriate material standards as specified or as agreed upon between purchaser and supplier.