| 摘要 |
PURPOSE:To obtain the Ni-based super alloy of a specific compsn. for the above nozzle which alloy has excellent thermal fatigue resistance and high-temp. strength and particularly excellent creep rupture strength and can be welded by adjusting the amts. of the Al, Ti, etc., to be added to the super alloy to slightly smaller amts. CONSTITUTION:The nozzle of the gas turbine which brings the combustion gas by compressed air in a combined composite power generating system into collision against the blades on a disk through the nozzle has one piece of vane part and side walls at both ends thereof and is disposed on the outer side of the rotating blade. This nozzle is formed of the Ni-based super alloy having the compsn. which consists, by weight%, of 0.05 to 0.20 C, 15 to 25 Co and Cr, respectively, 1.0 to 3.0 Al, Ti and Nb, respectively, 5 to 10 W, and >=, 55 Ni, and in which the quantity of the (Al+Ti) and the quantity of the W are within the lines successively connecting the respective points A (2.5, 1.0), B (3, 10), C (5, 7.5), D (5, 5), E (3.5, 5), and F (2.5, 7.5) of Fig. The precipitation quantity of a gamma phase which is the basic strengthening factor of this alloy is suppressed to a slightly lower level and the weldability is improved.
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