| 摘要 |
PURPOSE:To manufacture a structural member free from generation of cracks in the weld zone in the stage of stress relief annealing treatment after electron beam welding by regulating at least either of steel members to a low C-Cr-Mo steel having specific compsn. CONSTITUTION:In a structural member contg. a weld zone such as a turbine diaphragm, the compsn. of at least either of steel members to be welded is formed with, by weight, 0.05 to 0.1% C, <=0.8% Si, 0.40 to 1.15% Mn, 0.94 to 2.62% Cr, 0.40 to 1.15% Mo, 0.0005 to 0.0015% B, 0.01 to 0.5% Ti and <=0.002% S, furthermore, at need, with 0.001 to 0.1% Ca and Mg and the balance Fe with inevitable impurities. The structural member is subjected to electron beam welding and the weld zone is then subjected to stress relief annealing. In this way, the structural member contg. a weld zone having no fear of generating stress relief annealing cracks can be obtd. |
