| 摘要 |
PURPOSE:To make the weld heat-affected zone disappear and to prevent the occurrence of residual stress, by performing the build-up welding with the metal to be intermediate medium of which the coefficient of thermal expansion is close to that of the blade material to the surface of the blade material, performing the refining heat treatment and then jointing the metal to be the intermediate medium and the corrosion-resisting piece. CONSTITUTION:The build-up welding is performed to the roughly worked blade part 1 with the usual arc welding process. This filler metal is a material to be the metal for the intermediate medium and the alloy of Inconel line is used for this object. With this welding, the heat-affected zone 5 is formed to the blade material and the highest hardness at this zone reaches above 500 in Vickers hardness. Then, in order to remove this abnormal hardened part, the refining heat treatment is carried out. As one example, by being cooled gradually after having been heated for 3 hours at 620 deg.C, the hardness of the heat-affected zone becomes about 270 and shown a value close to the base of the blade material. Then, the finishing work is carried out and the welding is performed with the electron beam 6 while jointing with the corrosion-resisting piece 2. Because a heat source having a good efficiency of energy concentration is used at this welding, the heat affection does not reach the blade material. |
