Stainless Steel 303 is a free machining stainless steel. Due to the addition of sulfur this 18-8 chrome nickel stainless steel has enhanced machinability where before it was tough and difficult to machine.   Stainless Steel 303 is widely used in the screw machine industry, as well as for use in shafts, valves and fittings. Stainless Steel 303 is not recommended for vessels containing gases or liquids under high pressure.