Steel for nuclear pressure vessels and manufacturing method thereof

Abstract

The invention discloses a kind of steel for nuclear pressure vessels and a manufacturing method thereof. The manufacturing method comprises the following steps of: 1) smelting and plate blank casting, wherein the steel comprises the following components in percentage by weight: 0.05-0.20% of C, 0.10-0.40% of Si, 0.75-1.6% of Mn, 0.15-0.6% of Cr, 0.010-0.04% of Nb, 0.008-0.03% of Ti, 0.030-0.050% of Alt, 0.0010-0.0050% of Ca, 0.003-0.012% of N, less than or equal to 0.010% of S, less than or equal to 0.012% of P, less than or equal to 0.003 wt. % of Sn, less than or equal to 0.002% of Sb, less than or equal to 0.003% of As, and the balance of Fe and inevitable impurities, wherein Alt / N is greater than or equal to 2; 2) hot rolling, wherein the heating temperature of a plate blank is 1100-1250 DEG C, the first-stage rolling temperature is 950-1020 DEG C, the first-stage reduction ratio is greater than or equal to 80%, the second-stage rolling temperature is 780-900 DEG C, and the second-stage reduction ratio is greater than or equal to 60%; and 3) cooling and coiling, wherein the cooling speed is 4.0-15 DEG C / s, and the coiling temperature is 590-680 DEG C; and through a controlled rolling and cooling process, the microscopic structure of the obtained steel for nuclear pressure vessels is a fine ferritic and pearlitic structure.

Description

Technical field [0001] The invention relates to the field of steel for nuclear power, in particular to a steel for nuclear electric pressure vessels and a manufacturing method thereof, which can meet the requirements of structural parts or linings of nuclear electric pressure vessels. The thickness of the steel plate is 2.5-16mm with fine grained ferrite. Pearlite structure, its yield strength is greater than 265MPa, tensile strength is 410-590MPa, elongation is more than 22%, and it has excellent low temperature (-20°C) impact toughness and 300°C instantaneous tensile properties and is stable after simulated post-weld heat treatment The mechanical properties. Background technique [0002] In recent years, changes in the power energy structure and the increase in energy demand have promoted the development of steel for nuclear power. There are three main types of nuclear power materials. One is the zirconium alloy system, which is widely used in the fuel cladding of the thermal ...

AI Technical Summary

Problems solved by technology

[0005] Although the increase in the content of alloying elements in steel can obtain excellent mechanical properties and welding properties, for general nuclear reactor component steels, if high-strength steel, stainless steel or heat-resistant steel with more alloying elements is used, it will not only increase the manufacturing cost of the material. Difficulty, but also increases the manufacturing cost of the product, so it does not have good economic and social benefits

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