Republic HP 9-4-45 is a heat treated alloy steel capable of developing a yield strength of 250,000 psi with superior toughness characteristics. It is designed for sheet and thin-walled forged sections. It is also designed for heavy forging where an isothermal heat treatment is employed. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-179. Producer or source: Republic Steel Corporation, Titanium Division.