Heat-resisting alloy for 700-DEG C ultra-supercritical steam turbine rotor and preparation method thereof

Abstract

The invention relates to heat-resisting alloy for a 700-DEG C ultra-supercritical steam turbine rotor and a preparation method thereof, and belongs to the technical field of heat-resisting alloy. The alloy comprises the following ingredients by weight percent: 0.04 to 0.06 percent of C, 19 to 21 percent of Cr, 8.6 to 9.0 percent of Mo, 11 to 13 percent of Co, 0.40 to 0.80 percent of W, 1.10 to 1.30 percent of Al, 1.20 to 1.40 percent of Ti, 0.20 to 0.50 percent of Nb, less than or equal to 0.15 percent of Fe, 30 to 50ppm of B, 0.01 percent of Zr, 0.002 percent of Mg and the balance of Ni and impurities; wherein, the content of Al and Ti needs to satisfy the following condition: (Al+Ti) is more than or equal to 2.5 percent and less than or equal to 2.6 percent, and Ti / Al is more than or equal to 1.0 or less than or equal to 1.1. A VIM, VAR and ESR triplet process is used for smelting the alloy, soft-sheath forging is adopted, and the heat-resisting alloy has advantages that the comprehensive performance is excellent and the alloy is suitable for manufacturing the 700-DEG C ultra-supercritical steam turbine rotor.

Description

technical field [0001] The invention belongs to the technical field of heat-resistant alloys, in particular to a heat-resistant alloy for a 700°C ultra-supercritical steam turbine rotor and a preparation method thereof. The nickel-based heat-resistant alloy with excellent comprehensive properties can be used as a 700°C ultra-supercritical thermal power unit. Steam turbine high and medium pressure rotor material. Background technique [0002] Improving the steam parameters of thermal power units is the most important measure to improve the thermal efficiency of the unit and realize coal saving and emission reduction. With the development of traditional ferritic and austenitic heat-resistant steel technology, 600 ℃ ultra-supercritical thermal power units can now be built in batches around the world. In recent years, the successful development of new 9Cr-3W-3Co series ferritic heat-resistant steel and Sanicro25 new austenitic stainless steel has made it possible to build 630 ℃...

AI Technical Summary

Problems solved by technology

[0004] The development of rotor materials for 700°C ultra-supercritical steam turbines is of great significance, but there are great technical difficulties, and no major breakthroughs have been made so far

Adding a large amount of alloying elements to improve the high-temperature performance of the alloy can easily cause segregation of alloying elements and other metallurgical defects, increasing the difficulty of smelting and manufacturing the alloy

The rotor has been in service for decades, and the coarsening or transformation of precipitated phases in the alloy will lead to a decrease in the performance of the alloy, which seriously threatens the safe operation of the entire unit

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