ALLOY 300M is an alloy steel offering a combination of hardenability, ductility and toughness at tensile strengths from 280,000 to 320,000 psi. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-81. Producer or source: Various alloy steel mills (licensed).