Abstract Atlas 303 is a free-machining austenitic stainless steel. It is primarily used when production involves extensive machining in automatic screw machines. The sulfur addition which is responsible for the improved machining and galling characteristics of Atlas 303 lowers its corrosion resistance to below that of type 304 austenitic stainless steel. Compared with the other austenitic grades, Atlas 303 has excellent toughness, although its sulfur content reduces its toughness slightly. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SS-1351. Producer or source: Atlas Steels.