A w-containing high-strength low-alloy heat-resistant steel resistant to reheat cracks

Abstract

Steel, including the following element ratios (in mass percent amounts): carbon (C): 0.04-0.11%; silicon (Si): 0.50% or less; manganese (Mn): 0.10-0.60%; phosphorus (P): 0.03% or less; sulphur (S): 0.01% or less; nicide (Ni): 0.40% or less; chromium (Cr): 1.90-2.60%; vanadium (V): 0.20-0.30%; niobium (Nb): 0.02-0.08%; molybdenum (Mo): 0.05-0.30%; tungsten (W): 1.45-1.75%; titanium (Ti): 0.01-0.06%; boron (B): 0.001-0.012%; aluminum (Al): 0.03% or less; nitrogen (N): 0.01% or less; the balance being iron (Fe) and impurities. The contents of C and B satisfy the following inequality: (% B) −1.2×(% C)2+0.30×(% C)−0.01.

Description

technical field [0001] The invention belongs to the technical field of heat-resistant steel, and in particular relates to a high-strength, low-alloy heat-resistant steel, which has excellent reheat crack resistance, and is resistant to the heat-affected zone of coarse grains formed during post-weld heat treatment or high-temperature service. Insensitive to intergranular cracks. Background technique [0002] In order to reduce the environmental pollution caused by coal-fired power generation, it is necessary to develop efficient and clean super (super) critical thermal power units. At present, the main way to improve the efficiency of thermal power plants is to increase the steam temperature and pressure, which puts forward higher requirements for the high temperature and high pressure resistance of materials, and requires the development of high-strength heat-resistant steel to meet the needs of boiler parameters. [0003] At present, the development of boiler steel has two...

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Problems solved by technology

In addition, it is also proposed to suppress reheating cracks by adopting harsh welding processes, such as increasing the preheating temperature, adopting multi-layer welding passes or tempering passes, or increasing intermediate heat treatment, etc. These technological measures increase the process and increase the labor intensity. , reduces welding efficiency, greatly increases production costs, and the effect of preventing reheat cracks is not satisfactory, and does not fundamentally solve the problem

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