Refractory steel of anti intercrystalline corrosion, and preparation method

Abstract

This invention relates to a quenching method for preparing refractory austenitic steel with high intercrystalline corrosion resistance used in pressure furnace of thermal power sets. The refractory austenitic steel is composed of: C 0.058-0.086 wt.%, Si less than or equal to 3 wt.%, Mn 0.5-0.9 wt.%, P less than or equal to 0.04 wt.%, S less than or equal to 0.03 wt.%, Cr 17..0-19.0 wt.%, Ni 7.5-10.5 wt.%, Cu 2.5-3.5 wt.%, Nb 0.3-0.7 wt.%, N 0.09-0.12 wt.%, B 0.001-0.010 wt.%, Al 0.003-0.03 wt.%, and Fe. The method comprises: smelting, forging at 1100 deg.C at the beginning and not lower than 900 deg.C in the end, and solid-solution-treating at 1100-1200 deg.C by rapidly cooling to room temperature at a rate of 650 deg.C / 2 h. The refractory austenitic steel has such advantages as rational formula, simple and stable process, and no intercrystalline corrosion.

Description

[0001] Field [0002] The invention belongs to the technical field of alloy steel manufacture. The invention is especially suitable for preparing austenitic heat-resistant alloy steel for intergranular corrosion resistance in high-pressure furnace boiler steel of thermal power units and the preparation method of the heat-resistant steel. Background technique [0003] In the prior art, 10Cr18Ni9Cu3NbNB austenitic heat-resistant steel is used in thermal power units and is a high-grade high-pressure boiler steel. At present, in the new thermal power plants in my country, this steel grade is also widely used in ultra / ultra supercritical units. The 10Cr18Ni9Cu3NbNB steel grade is the S30432 steel grade in ASMESA213Code Case2328-1, and its specific composition weight % is: C 0.07-0.13%; Si≤0.3%; Mn≤1.0; P≤0.040%; S≤0.03%; Cr 17.0- 19.0%; Ni 7.5-10.5%; Cu 2.5-3.5%; Nb 0.3-0.6%; N 0.05-0.12%; B 0.001-0.010%; Al 0.003-0.03%; the rest is Fe. Since the S30432 steel grade in CC2328-1 i...

AI Technical Summary

Problems solved by technology

However, the 10Cr18Ni9Cu3NbNB austenitic heat-resistant steel in production generally cannot pass the intergranular corrosion test of the E method in GB43345.

Images