| 摘要 |
There is provided an Ni-based heat resistant alloy consisting of C‰¤0.15%, Si‰¤2%, Mn‰¤3%, P‰¤0.03%, S‰¤0.01%, Cr: 15% or more and less than 28%, Mo: 3 to 15%, Co: more than 5% and not more than 25%, Al: 0.2 to 2%, Ti: 0.2% to 3%, Nd: fn to 0.08%, and O‰¤0.4nod, further containing, as necessary, at least one kind of Nb, W, B, Zr, Hf, Mg, Ca, Y, La, Ce, Ta, Re and Fe of specific amounts, the balance being Ni and impurities, wherein, fn = 1.7 × 10 -5 d + 0.05{(A1/26.98) + (Ti/47.88) + (Nb/92.91)}. In the above formula, d denotes an average grain size (µm), and each symbol of an element denotes the content (mass%) of that element. If the alloy contains W, Mo + (W/2) ‰¤ 15% holds. In this alloy, the dramatic improvement in ductility after long-term use at high temperatures can be achieved, and the SR cracks that pose a problem in repair welding and the like can be avoided. Therefore, this alloy can be used suitably as a pipe material, a thick plate for parts having heat resistance and pressure resistance, a rod material, a forging, and the like in power generating boilers, chemical industry plants, and the like. |
