INDUCTION HARDENING FOR GRAIN PULVERIZER

A method for thermally treating a roller of a grain pulverizer is provided to favorably pulverize grains without generating high heat due to friction by obtaining the desirable hardness by a simple high-frequency heat treatment operation and to prevent the deformation or separation of a surface part. The heat treatment method for manufacturing a cast roller by cutting, heating the roller by high frequency, and then quickly cooling down the heated roller under the predetermined atmosphere comprises the steps of: pre-heating a center part of the roller by high frequency at the temperature of 830~850‹C for 10~15 minutes(S2); pre-heating the roller by high frequency at the temperature of 870~890‹C for 10 minutes(S3); and cooling down the roller by water(S4).