| 摘要 |
PROBLEM TO BE SOLVED: To provide an austenitic heat-resistant alloy member which is excellent in creep strength and cracking resistance in welding by multilayer welding and has a thickness beyond 30 mm.SOLUTION: An austenitic heat-resistant alloy member has a thickness greater than 30 mm and a chemical composition comprising 0.03-0.15% C, 1% or less Si, 2% or less Mn, 0.03% or less P, 0.01% or less S, 40-55% Ni, 20-35% Cr, 3-10% W, 0.01-1.2% Ti, 0.3% or less Al, 0.0001-0.01% B, 0.02% or less N, 0.01% or less O and remaining Fe and impurities and meets conditions: (average crystal grain size (μm) of the region from the surface of the member to the depth of 0.2 mm)≤-20×{Ti+(W/10)-5×B}+65 and -15×{10×B+Ti+(W/10)}+100≤(average crystal grain size (μm) of the region other than individual surface sides corresponding to 25% of the thickness of the member)≤-75×{10×B+Ti+(W/10)}+700. |
