金沢大学理工研究域機械工学系This paper deals with the machinability of BN (Boron Nitride) free-machining steel in turning. Tested work materials were plane carbon steel JIS S45C and BN free-machining steel. The JIS S45C used as the standard. The tool wear in turning BN free-machining steel was smaller than that in turning standard steel. BN free-machining steel showed slightly lower cutting temperature and smaller cutting force to compare with standard steel at the tested cutting speeds. At the tool wear region of P grade carbide tool after turning BN free-machining steel at high cutting speed, Al and N were detected as a layer. It is thought that one of the main reasons of outstanding machinability of BN free-machining steel is the deposited layer containing Al and N acts as diffusion barrier at the tool-chip interface. In turning larger Al content BN added steel with higher Ti content cutting tool, the influence of BN addition on the tool wear reduction was more remarkable.[議事録
