A steel for pressure-bearing boundary parts of steam generators in nuclear power plants and its manufacturing method

Abstract

The invention discloses steel for a pressure bearing boundary part of a steam generator in a nuclear power plant and a manufacturing method of the steel. The steel comprises 0.15% to 0.22% of C, 0.10%to 0.30% of Si, 0.55% to 0.75% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, 0.30% to 0.60% of Ni, 0.70% to 1.10% of Cr, 0.80% to 1.50% of Mo, 0.020% to 0.040% of Al, 0.010% to 0.030% of Nb, 0.0005% to 0.002% of B, less than or equal to 0.05% of Cu and the balance of Fe and unavoidable impurities. A converter-continuous casting process is adopted when the thicknessof a steel plate is less than 80mm, wherein the heating temperature is 1180-1250 DEG C, the rolling starting temperature is greater than or equal to 1100 DEG C, and the rolling finishing temperature is greater than or equal to 900 DEG C; an electric furnace-die casting process is adopted when the thickness of the steel plate is greater than or equal to 80mm, wherein the heating temperature is greater than or equal to 1200 DEG C, the rolling starting temperature is greater than or equal to 1050 DEG C, and the rolling finishing temperature is greater than or equal to 850 DEG C; quenching and tempering treatment are performed on the steel plate after rolling; and the produced steel plate of 30-150mm has good high temperature performance and strong strength-toughness matching.

Description

technical field [0001] The invention belongs to ferrous metal materials, and relates to a steel metal material for nuclear power, in particular to a steel material with good comprehensive mechanical properties and internal quality for nuclear power steam generator pressure-bearing boundary parts and a manufacturing method thereof. Background technique [0002] Due to its advantages in cleanliness and economy, nuclear energy has gradually become an important energy used by countries all over the world, and it is an important part of the primary energy consumption structure of developed countries in the world. Because nuclear power plants consume very little nuclear fuel during operation, they can generate a large amount of electricity, which is much higher than thermal power generation in terms of power generation efficiency. As for the characteristics of my country's energy consumption structure dominated by coal, it not only bears the direct economic pressure of economic co...

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Problems solved by technology

However, the maximum thickness of the steel plate is 100mm, and the tensile strength of the 100mm steel plate in the specification is only 430MPa at room temperature, and the tensile yield strength at 300°C is only 199MPa

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