Friction Stir Processing Of Skd61 Tool Steel

In this study, SKD61 tool steel was friction stir processed (FSP) using a polycrystalline cubic boron nitride (PCBN) tool. Microstructure evolution and mechanical property in FSP zone were investigated. Microstructural observation results showed that the microstructures in FSP zone surface were fine grains in the range of 1 - 4 mu m due to large plastic deformation during FSP. Microhardness test results showed that the average hardness value in FSP zone was 773 HV, 3.7 times the hardness in base metal (210 HV). The wear test results showed that FSP surface showed a significantly lower wear rate than that of the base material at all loads. The relation between microstructural evolution and mechanical property in FSP zone was discussed.