| 摘要 |
PURPOSE:To improve the corrosion resistance and strength by performing each one layer of multi-electrode submerged arc welding using a specific two-phase stainless steel wire for the inside surface side and a specific austenitic stainless steel wire for the outside surface side then subjecting the weld zone to a soln. heat treatment. CONSTITUTION:The inside surface side is welded by using a two-phase wire contg. <=0.05wt% C, <=0.6% Si, 0.5-1.5% Mn, <=0.03% P, <=0.015% S, 4.0-7.0% Ni, 21-26% Cr and 1.0-5.0% Mo and having 22-33% Cr equiv. expressed by the formula I and 8-13% Ni equiv. expressed by the formula II. The outside surface side is subjected to multi-electrode submerged arc welding using an austenitic wire contg. <=0.05% C, 0.2-1.0% Si, 1.0-2.0% Mn, 9-14% Ni, 17- 21% Cr and 0-3.0% Mo and having 18-23% Cr eq. and 10-17% Ni equiv. and thereafter the weld zone is subjected to a soln. heat treatment at 1,000-1,100 deg.C. The strength and corrosion resistance are improved by the above-mentioned method. |
