| 摘要 |
PURPOSE:To improve wear resistance, by individually melting and hardening a part of predetermined width from and a part inside the corner of a member having a chilled surface layer preformed by melting and then rapidly cooling the surface of a cast iron member having the corner. CONSTITUTION:A cam shaft 1 for an internal combustion engine, for instance, is properly provided with a cam 2 and equipped with a corner 2b cutting the surface 2a of the cam at a right angle. The entire surface of said cam 2 is converted into a chilled state by melting and then rapidly cooling it. Thereafter, a part 3 of predetermined width from an edge 2c constituting the outside end of the corner 2b of the cam surface 2a and a part 4 inside the corner 2b are individually melted and hardened. |
