CuSn7Zn4Pb7 (RG7, Promet 7, Promet 737, JM1, CC493K)

Gunmetal for more heavily loaded applications

CuSn7Zn4Pb7 is also known as RG7, Promet 7 and Promet 737 — in international standards the material appears under the designations JM1 and CC493K. The alloy is an intermediate between the gunmetals and the leaded tin bronzes: it withstands higher surface pressure and offers better sliding properties than Promet 5, and its performance is close to that of the leaded tin bronzes. Typical applications include the sliding bearings of earth-moving machinery and applications loaded more heavily than Promet 5.

Standard equivalents

DIN 1705 CuSn7PbZn · UNS C93200 · SAE 660 · ASTM B505