COPPER ALLOY No. 521 is a copper-tin alloy which has been deoxidized with phosphorus. It has excellent strength and corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on low temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-250. Producer or source: Copper and copper alloy mills.