2023 年 64 巻 1 号 p. 191-195
Demand for lead-free, free-cutting brass is increasing in response to lead regulations in Europe. The authors of this paper have attempted to develop a lead-free brass with an α + β two-phase microstructure, which is different from existing C6932 alloy. As a result of basic investigations, it was found that the addition of Si to β-brass dramatically reduces the cutting resistance due to an effect that appears to be a reduction in the stacking defect fault energy, and that if phosphorus compounds are dispersed in such β-brass, the compounds make stress concentration sources improving chip fragmentation during cutting. Based on these findings, we have succeeded in developing a new free-cutting α + β brass (62.5Cu–1Si–0.07P–Zn). The developed alloy contains about 55% alpha phase and has excellent machinability and 1.3 times higher strength than C3604.
This Paper was Originally Published in Japanese in J. Japan Inst. Copper 61 (2022) 323–328.
