AISI 1139 is a carbon steel containing 1.35-1.65% manganese and 0.13-0.20% sulfur to furnish free-machining characteristics. It is recommended especially for high-production machined products. Among its many applications are splined shafts, screws, arbors, tool holders and propeller shafts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-82. Producer or source: Carbon steel mills.