HEAT-RESISTANT STEEL AND GAS TURBINE MADE OF THE SAME

摘要

Heat-resistant steel consisting, in weight percent, of 0.05 to 0.2 % of C, up to 0.5 % of Si, up to 0.6 % of Mn, 8 to 13 % of Cr, 1.5 to 3 % of Mo, 2 to 3 % of Ni, 0.05 to 0.3 % of V, at least one of Nb and Ta with the sum being from 0.02 to 0.2 %, 0.02 to 0.1 % of N, with the ratio Mn/Ni being up to 0.11, and the balance consisting substantially of Fe. The heat-resistant steel of the present invention is used at least for a turbine disc of a gas turbine consisting of a turbine shaft, a plurality of turbine discs connected to the shaft with spacers between them by turbine stacking bolts, turbine buckets implanted in the discs, a distant piece connected to the disc by the bolts, a plurality of compressor discs connected to the distant piece by compressor stacking bolts, compressor blades implanted in the compressor discs and a compressor stub shaft shaped integrally with the initial stage of the compressor discs. Furthermore, the heat-resistant steel of the invention can be used for the stacking bolt, the spacer, the distant piece and the compressor blade. The heat-resistant steel of the present invention has the characteristics such as creep rupture strength of at least 50 kg/mm<2> at 450 DEG C for 10<5>C hours and a 25 DEG V-notch Charpy impact value of at least 5 kg-m/cm<2> after heat treatment at 500 DEG C for 10<3> hours.