Study on Damaged Surface Layers in Hot Machining (2nd Report)

There are many heating methods in hot machining. The author used the Local Electric Resistance Heating Method. The surface treated by cutting with a cutting tool has a layer different from that of the inside. We call this layer the Damaged Surface Layer. In this report hardness and fatigue life, when quenchtempered carbon steel is cut with a cemented carbide tool under Local Electric Resistance Heating, are shown. The results of these experiments are as follows : (1) When quench-tempered carbon steel is hot-machined, the cutting surface shows little softness. (2) Fatigue life increases with an increase of hardness and the heating current. (3) The most hardend layer generated by repeating contact stress exists in about 0.2mm below the contact surface.