Refractory steel for vane of steam turbine of ultra supercritical fossil power plant and manufacturing method

Abstract

The invention provides refractory steel for a vane of a steam turbine of an ultra supercritical fossil power plant, which is characterized by comprising the following chemical components calculated according to mass percent: 10.0 to 12.0 of chromium, 0.1 to 0.6 of molybdenum, 2.4 to 3.0 of tungsten, 1.0 to 4.0 of cobalt, 0 to 0.5 of nickel, 0.2 to 1.0 of manganese, 0.010 to 0.019 of nitrogen, 0.10 to 0.30 of vanadium, 0.03 to 0.10 of niobium, 0.005 to 0.015 of titanium, 0.06 to 0.15 of carbon, 0.008 to 0.015 of boron, 1.0 to 3.0 of copper, 0.002 to 0.01 percent of zirconium and the balance asiron and unavoidable impurities; a manufacturing method of the refractory steel for the vane of the steam turbine of the ultra supercritical fossil power plant comprises the following steps: processing the compositions of the raw materials of the constituent elements sequentially by smelting and pouring so as to obtain a steel ingot of the refractory steel, then forging the steel ingot and finally, carrying out heat treatment; and the refractory steel for the vane of the steam turbine of the ultra supercritical fossil power plant and the manufacturing method are characterized in that a heat-treatment process has the steps of keeping oil cooling for 0.5 to 1h at 1050 to 1150 DEG C and keeping air cooling for 1 to 2h at 720 to 790 DEG C. The refractory steel has favorable corrosion resistance and creep resistance at high temperature, has stable tissues in the high-temperature long-time use procedure and can be used as a material of a vane for a steam turbine of an ultra supercritical fossil power plant above 620 DEG C.

Description

technical field [0001] The invention relates to a heat-resistant steel for steam turbine blades of an ultra-supercritical thermal power unit and a manufacturing method thereof, belonging to the technical field of metal materials. Background technique [0002] In order to improve the efficiency of thermal power generation units and reduce CO 2 The key to the emission of gas is to increase the steam parameters of the thermal power generation unit, that is, to increase the temperature and pressure of the steam, but the degree of improvement of the parameters mainly depends on the materials used. The microstructure of 12Cr series ferritic heat-resistant steel in the quenched and tempered state is tempered lath martensite, and M is distributed in the original austenite grain boundary and martensite lath boundary 23 C 6 Type carbides contain high-density MX-type nano-precipitated phases in the lath boundaries and laths, so in addition to high corrosion resistance, they also have...

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Problems solved by technology

Existing steam turbine blade materials cannot meet the performance requirements under the condition of steam temperature of 620°C

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