| 摘要 |
PURPOSE:To prevent the deformation in the shape of a shoulder part owing to melting by removing the black skin layer formed on the sliding surface of a cast cam, making the side surface intact as cast and heating and melting the sliding surface by a torch thereby hardening the same to white iron. CONSTITUTION:A cam 1 is cast in one body with a cam shaft 2, and the sliding surface 3 of the cam is ground to remove the black skin layer formed on the casting surface. The side surface 4 of the cam is made intact as cast and the black skin layer is allowed to remain. The cam 1 and the cam shaft 2 are preheated to about 400 deg.C then a torch 5 is moved circumferentially while it is oscillated and moved in the transverse direction of the surface 3. The output current of the torch 5 is regulated to about 120A in the transverse directions (c)-(d) of the surface 3 and to about 80A in the directions (a)-(c), (d)-(b). Then the torch 5 moves on the surface 3 by drawing a locus K and heats and melts the sliding surface over the entire part thereof, thereby forming a white iron hardened layer. |
