AISI 304 stainless steel (UNS S30400) is the most commonly used material in stainless steels, and is usually purchased in an annealed or cold worked state. Because SS304 contains 18% chromium (Cr) and 8% nickel (Ni), it's also known as 18/8 stainless steel. Type 304 has good processability, weldability, corrosion resistance, heat resistance
SAE steel grades. The SAE steel grades system is a standard alloy numbering system (SAE J1086 - Numbering Metals and Alloys) for steel grades maintained by SAE International . In the 1930s and 1940s, the American Iron and Steel Institute (AISI) and SAE were both involved in efforts to standardize such a numbering system for steels.