Steel for boiler and method of producing the same

Abstract

The invention discloses steel used for a boiler and a manufacture method thereof. The invention is mainly characterized by including the chemical elements with the following weight percentage: 0.04 to 0.10 percent of C, equal to or less than 0.50 percent of Si, equal to or less than 2.00 percent of Mn, 8.00 to 12.00 percent of Ni, 17.00 to 19.00 percent of Cr, 0.8 to 1.00 percent of Nb, equal to less than 0.25 percent of Cu, equal to or less than 0.015 percent of S, equal to or less than 0.040 percent of P, 0.005 to 0.040 percent of B, 0.10 to 0.20 percent of N, 0.005 to 0.100 percent of N and the rest is Fe as well as unavoidable impurities. The process flow of the invention is as follows: primary melting by an electric arc furnace, AOD refining, die casting, primary rolling, roughing or continuous casting, rolling a tube blank in a hot way and manufacturing a tube. The steel used for a boiler and a manufacture method thereof can solve the problems that steel tube used by the prior boiler is lower in intensity and is easy to generate a fatigue crack, and the like. Besides, the steel used for a boiler and a manufacture method thereof can further improve the comprehensive mechanical performances and the service life of the steel tube used for a boiler.

Description

technical field [0001] The invention relates to composition design and manufacturing method of austenitic heat-resistant stainless steel, in particular to high-strength, high-temperature-resistant and high-pressure steel used in boilers of supercritical thermal power generation units. Background technique [0002] With the sharp increase in the national electricity demand, the development of thermal power units with large capacity, supercritical and ultra-supercritical parameters is the current world trend. The higher the parameters (pressure and temperature), the more energy it can convert and the more efficient the unit will be. Metal materials for boilers of supercritical and ultra-supercritical generator sets are constantly being developed and updated, requiring boiler steel not only to have sufficient long-term durability, but also to have high oxidation resistance. [0003] At present, more than 80% of my country's power generation takes the form of thermal power gene...

AI Technical Summary

Problems solved by technology

[0009] The object of the present invention is to provide a kind of steel for boiler and its manufacture method, to solve the problems of low strength and prone to fatigue fracture and steam corrosion of steel pipe for boiler of existing supercritica