About 715|Copper-nickel 70/30 (70% copper, 30% nickel). The premium marine copper alloy. Outstanding resistance to seawater corrosion, biofouling, and stress corrosion cracking. This is condenser tube material, desalination equipment material, and offshore platform piping material. Machines harder than pure copper — the nickel makes it tougher and more work-hardening. Use carbide at moderate speeds with positive rake and flood coolant. Not as gummy as
C110 since the nickel gives the chips more body. Compare to C110 (better conductivity, terrible marine corrosion resistance) and C464 naval brass (cheaper, adequate for less demanding marine applications).