Steel for nuclear power pressure equipment with high toughness, high ductility and low irradiation embrittlement and making method thereof

Abstract

The invention discloses a steel for nuclear power pressure equipment with high toughness, high ductility and low irradiation embrittlement and a making method thereof. The steel comprises the following chemical compositions in percentage by weight: 0.08-0.15 percent of C, 0.20-0.35 percent of Si, 0.80-1.60 percent of Mn, P no more than 0.012 percent, S no more than 0.005, 0.01-0.05 percent of Alt, 0.08-0.015 percent of Ti, N no more than 0.010 and the balance of Fe and unavoidable impurities. The chemical compositions of the steel also satisfy that Ni+Cr+Mo+Cu is no more than 0.70, Alt / N is no less than 2.0, Cu+6Sn is no more than 0.30 and Sn+Sb+As+Pb no more than 0.020. In the invention, the making method in a controlled rolling state and a normalized state is designed according to the requirements of different delivery states of steel products and different steel thicknesses, has the advantages of simple rolling technology and high product qualified rate of steel plates and can towel meet the requirements of mass production. The steel can be widely used for making second generation nuclear power pressure equipment, second generation improved nuclear power pressure equipment and third generation nuclear power pressure equipment.

Description

Technical field [0001] The invention belongs to the technical field of low-carbon microalloy steel, and specifically relates to a steel with high toughness, high ductility and low radiation embrittlement for nuclear power pressure-bearing equipment and a manufacturing method thereof. Background technique [0002] The steel for nuclear power pressure equipment is suitable for the manufacture of nuclear reactor containment, pressure vessel, pressure pipe and other materials that support the basic structure of the reactor. It also protects the operation of nuclear power equipment and prevents the spread of radioactive rays. It is the last safety barrier of the reactor. . According to the different types of reactors and the different functions of basic structural materials, the safety level requirements of steel used in nuclear power pressure equipment are also different. At present, the pressure-bearing equipment such as A42, A52, P265GH, P295GH, P355GH, etc. are mostly used in nuc...

AI Technical Summary

Problems solved by technology

The advantages of these two steels are that they both have high strength and high toughness, but the radiation embrittlement sensitive elements Cu and V are added to the chemical composition, and the residual elements in the steel plate such as P, S, Sn, Sb, As, etc. The control level is not high, which aggravates the radiation embrittlement effect of the steel plate

At the same time, in order to improve the strength of the steel, more alloying elements are added to these steel components, resulting in a certain degree of reduction in the purity of the steel, and an increase in the degree of segregation. Therefore, the strength of the steel is too high, resulting in a decrease in ductility, which is not suitable for manufacturing. Pressure-bearing equipment such as nuclear power containment, brackets, corbels, and secondary pipelines that require high comprehensive performance such as ductility, toughness, and weldability

Therefore, it is not suitable for manufacturing the second-generation improved and third-generation nuclear power pressure equipment

[0004] In addition, in the actual production process, many stainless steels such as Z2CN18-10 have been used in nuclear power pressure equipment. These stainless steels have high strength and low yield ratio, good fatigue resistance and fracture toughness, and have relatively high Good corrosion resistance and low temperature toughness, but the disadvantage of these stainless steels is that their chemical composition contains high content of precious alloying elements Ni, Mo, Cr, etc., which makes the steel manufacturing cost higher, and the production thickness of the stainless steel plate is also limited. Restrictions, and strict requirements on the steel plate welding process in the later stage, resulting in an increase in the cost of the entire nuclear island construction project

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