Nuclear container steel with tensile strength of more than 690MPa level and production method

Abstract

The invention discloses a nuclear container steel with tensile strength of more than 690MPa level and a production method. The steel comprises the following chemical components in percentage by weight: less than or equal to 0.08 percent of C, 0.15 to 0.50 percent of Si, 1.30 to 1.60 percent of Mn, 0.01 to 0.05 percent of Alt, 0.42 to 0.70 percent of Ni, 0.32 to 0.60 percent of Mo, 0.10 to 0.30 percent of Cr, 0.01 to 0.04 percent of Ti, less than or equal to 0.008 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.005 percent of N, less than or equal to 0.03 percent of Cu, less than or equal to 0.007 percent of V, less than or equal to 0.005 percent of Sn, less than or equal to 0.005 percent of Sb, less than or equal to 0.010 percent of As, less than or equal to 0.005 percent of Pb, and the balance of Fe and inevitable impurities, wherein P, S, N, Cu, V, Sn, Sb, As and Pb are used as controlled elements. The production method comprises the following steps of: smelting clean steel, performing continuous casting, cooling casting blank to room temperature, heating the casting blank, performing heat preservation, rough rolling and finish rolling, quenching,tempering, and naturally cooling to room temperature. The steel can improve the safety and the reliability in the operation of a nuclear power plant, and has the advantages of high strength, low welding crack sensitivity, low radiation embrittlement effect and excellent tensile property and welding property at the temperature of 20 DEG C below zero.

Description

technical field [0001] The invention relates to steel for containers, in particular to steel for nuclear containers with a tensile strength greater than 690 MPa, high strength, low welding crack sensitivity, and low radiation embrittlement, and a production method thereof. Background technique [0002] Steel for nuclear vessels is used to manufacture nuclear island pressure vessels, evaporators, pressurizers, pressure pipes and other materials. Its role is to protect the operation of nuclear power equipment, prevent the spread of radioactive rays and support the basic structure of the reactor. It is the last safety barrier of the reactor. my country is vigorously developing nuclear power, and new nuclear power unit projects are being added every year. However, at present, manual arc welding is mostly used for steel welding for nuclear power, which has low welding efficiency and slow production rhythm, which cannot meet the needs of rapid development of nuclear power construc...

AI Technical Summary

Problems solved by technology

The shortcomings of the above three patented technologies are that they have not been designed according to the requirements for the use of steel for nuclear power plant pressure equipment, have not added suitable Cr and Mo alloys, and have not treated impurity elements (P, S, Cu, V, etc.), residual elements ( Sn, Sb, As, Pb, etc.) are strictly controlled, and there is no guarantee of low radiation embrittlement effect

The steel plate produced by the above-mentioned patented technology guarantees the welding performance and low radiation embrittlement effect of the steel plate, but the disadvantage is that more alloys such as Ni and Cr are added to the alloy composition, and the production process of alloy steel is adopted, so that smelting, rolling The process is more difficult and the production cost is higher

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