| 摘要 |
PROBLEM TO BE SOLVED: To provide an austenitic heat resistant member excellent in crack resistance at the time of welding, especially in the crack resistance on a surface in the vicinity of a weld zone when being multi-layer welded as a thick member.SOLUTION: An austenitic heat resistant member has a chemical composition containing, by mass%, C: 0.03 to 0.15%, Si≤1%, Mn≤2%, P≤0.03%, S≤0.01%, Ni: 40 to 55%, Cr: 20 to 35%, W: 3 to 10%, Ti: 0.01 to 1.2%, Al≤0.3%, B: 0.0001 to 0.01%, N≤0.02%, O≤0.01% and Fe and impurities as the balance. The austenitic heat resistant member has maximum roughness Rz of a member surface of 50 μm or less and maximum hardness of HV0.025(max) in a region from the member surface to a depth of 100 μm, and HV0.025 and Rz satisfy an expression of HV0.025(max)≤-1.2×Rz+380. The austenitic heat resistant member may contain one or more elements selected from Ca, Mg, REM, Co, Cu, Mo, V, Nb and Zr each of which has a specific amount in lieu of a part of Fe. |
