Comparison of Microstructure and Hardness of Phosphor Copper Ball Produced by Rolling and Upsetting Processes

The microstructure, hardness and surface temperature at the end of production of phosphorus copper ball with diameter of 25 mm by rolling and upsetting processes were comparably studied. The results show that compared with the rolling process, the surface of the phosphorus copper ball by upsetting process was smooth; the grain was obviously refined, and grain boundary was clear; the element distribution was uniform; the grains were mainly equiaxed and the number of columnar grains was relatively small. The maximum surface temperatures of the phosphorus copper ball far away from and near the outlet tank at the end of production by upsetting process were lower than those by the rolling process. The heart hardness of the phosphorus copper ball by upsetting process was obviously higher than that by the rolling process, and the surface hardness fluctuated less. Compared with the rolling process, the phosphorus copper ball by the upsetting process had the technical advantages of good quality, environmental protection and low energy consumption.