| 摘要 |
PURPOSE:To obtain a weld zone having excellent resistance to high-temp. corrosion by subjecting the entire circumference of a pipe in the boundary part between a weld metal and chromium diffused layer to build-up welding with prescribed weld input by a welding material having a specific chromium content. CONSTITUTION:The chromized pipes each consisting of a base metal 2 such as 17Cr-14Ni-Cu-Mo are welded to each other by the welding material of the same type as the metal 2 by which a weld metal 4 is formed. The surface of the metal 4 is welded over the entire surface by a high-chromium material and a weld metal 7 is formed in order to maintain the corrosion resistance of the metal 4. The boundary part between the chromium diffused layer 3 of the metal 2 and the metal 7 is subjected to one pass of build-up welding at about 1mm. width over the entire circumference of the pipe by the high-chromium material contg. >=22% Cr. Peeling and crack are not generated in the weld metal 6 welded by TIG welding with <=8,000J/cm weld heat input and therefore the resistance to high- temp. corrosion is improved. |
