PURPOSE: To offer the alloy having very excellent mechanical characteristic as well as excellent corrosion resistance and stress corrosion cracking resistance by incorporating specified amounts of Sn, Al, Mg and Cr into a copper alloy contg. a specified amt. of Ni.
CONSTITUTION: The copper alloy is constituted of, by weight, 10 to 20% Ni, 0.5 to 2.0% Sn, 1.0 to 3.0% Al, 0.001 to 0.05% Mg and 0.001 to 0.1% Cr. In the alloy, Ni improves the strength, elongation and corrosion resistance, but in the case of less than the lower limit, the effect is insufficient, and in the case of more than the upper limit, the hot workability is deteriorated. Sn and Al increase the strength and elongation, but in the case of less than the lower limit, the effect is insufficient, and in the case of more than the upper limit, the hot workability is deteriorated for Sn, and the castability is deteriorated for Al. Mg fixes S to be incorporated as stabilized MgS in a mother phase and improves the hot rollability, but in the case of less than the lower limit, the effect is insufficient, and in the case of more than the upper limit, the fluidity of the molten metal is deteriorated. Cr strengthens the grain boundaries in the ingot and improves the hot workability, but in the case of less than the lower limit, the effect is insufficient, and in the case of more than the upper limit, the castability is deteriorated.
KINOSHITA TATSUYA
TSUNO RIICHI
