| 摘要 |
PURPOSE:To obtain a turbine rotor having the improved mechanical property in a bearing part and having excellent safety and reliability by subjecting the bearing part of the turbine rotor to compression working to leave a compressive stress therein then subjecting the same to build-up welding. CONSTITUTION:A roll 4 attached to the tool rest 5 of a lathe, etc. is pressed to the bearing groove part 1a of a base material 1 for a turbine rotor, and is fed to accomplish compression working over the entire circumference in the part 1a, thereby leaving a compressive stress over the entire circumference in the part 1a. The 1st bead layer is formed by using a Cr-Mo steel or the like to the compression worked bearing part. The 2nd bead layer is then build-up welded thereon at the heat input larger than for the 1st bead layer to form the finer grains of the texture in the weld heat-affected zone of the root pass and to soften the hardened part of the weld heat-affected zone in the 1st bead layer. The 3rd and succeeding bead layers are build-up welded by the same stage as for forming the 2nd bead layer, and the layers are ground if necessary. The bearing part of the turbine rotor having improved toughness in the weld boundary part is obtd. by the above-mentioned method. |
