抄録
The transformation hardening method is experimentally proved to be practicable, and the fundamental characteristics of the method are investigated. Defocused and deflected by triangular wave in Y direction, the electron beam is directed over the surface of S 45 C (JIS) plate moving uniformly toward X direction. The plate is heated by the electron beam, and then self-quenched through conduction of heat. As a result, the hardened (Hv 600 or more) layer of 0.6 mm thickness and 10 mm width is obtained. The surface roughness of the layer is found to increase after hardening process. The average hardness of the hardened layer reaches maximum when the surface melts slightly. The transformation hardening mechanism by electron beam is explained by determining the temperature distribution in the uniformly moving semi-infinite medium with still and square heat source on it. The hypothesis is that isothermal line of 900°C shows the boundary of heat affected layer. The calculation with the hardening model shows good agreement with the experimental results.
