| 摘要 |
PURPOSE:To secure the joined part of the air-hardening steel free from the weld crack with the regular carbon steel by repeating the welding of the joint while the buttering or the surface to be joined of the air-hardened slab is preceded, grinding the reinforcement of weld, and executing the heat treatment at the prescribed temperature. CONSTITUTION:The air-hardening steel slab 1 having the composition consisting of, e.g., 0.15% C, 0.1% Si, 0.47% Mn, 9.2% Cr, 0.54% Mo, 1.9% W,0.05% Mb, 0.21% V, and the balance Fe is welded to the carbon steel slab 2 having the composition consisting of 0.12% C, 0.38% Si, 1.24% Mn, and the balance Fe. The build-up welding 3 is repeated from the upper and lower surfaces alternately while the buttering 4, 5 is preceded on the surface to be joined of the air- hardened slab 1 with the groove part being heated and held at Ms point to 100 deg.C, and after the welding of the reinforcement is finished, the reinforcement of weld is ground. Successively, the heat treatment is executed at the temperature of <=Ms point. This process remarkably relieves the reduction in the workability and the safety, the increase of the joining cost or the like. |
