HERCULOY 421, also known as Revere Alloy No. 421, is a low silicon bronze having tensile properties comparable to cartridge brass and corrosion resistance similar to that of copper 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: Cu-36. Producer or source: Revere Copper and Brass Inc..