The brass and its production manner and the part null 57 -

摘要

PROBLEM TO BE SOLVED: To obtain low-cost free-cutting brass practically free from Pb and having excellent thermal embrittlement characteristic and machinability.;SOLUTION: Molten-metal temperature at the casting of the free-cutting brass is ≥1,150°C. The free-cutting brass has a chemical composition containing, by mass, ≥57% Cu, 0.5 to 3.5% Bi, 0.001 to 2.0% Pb, 0.002 to 0.3% B and the balance Zn with inevitable impurities and has ≥140°C thermal embrittlement temperature, ≥30% index of cutting force and ≥10% index of chip breakability.;COPYRIGHT: (C)2006,JPO&NCIPI