Austenitic stainless steels are the most commonly used materials produced by ATI Allegheny Ludlum. This class of stainless steel includes both the 200 and 300 series alloys, which are hardenable by cold working. The 300 series alloys contain chromium and nickel as their major alloying additions. Type 304 (also known as 18-8) is the most widely used of all stainless steel alloys. The 200 Series alloys possess mechanical and corrosion resisting properties similar to 300 Series materials. They also exhibit high hardness and yield strength as well as excellent ductility and are usually non-magnetic.