CN111270143B

CN111270143B - Thick steel plate for nuclear power station containment equipment module and production method thereof

Info

Publication number: CN111270143B
Application number: CN202010194128.1A
Authority: CN
Inventors: 颜秉宇; 胡海洋; 王爽; 王勇; 段江涛; 李黎明; 孙殿东; 胡昕明; 欧阳鑫; 石峰涛
Original assignee: Angang Steel Co Ltd
Current assignee: Angang Steel Co Ltd; Shanghai Nuclear Engineering Research and Design Institute Co Ltd
Priority date: 2020-03-19
Filing date: 2020-03-19
Publication date: 2021-07-09
Anticipated expiration: 2040-03-19
Also published as: CN111270143A

Abstract

The invention provides a thick steel plate for a nuclear power station containment equipment module and a production method thereof, wherein the steel plate comprises the following components in percentage by weight: 0.11% -0.19% of C; 0.19% -0.49% of Si; 1.01-1.39% of Mn; p is less than or equal to 0.010 percent; s is less than or equal to 0.005 percent; 0.61% -0.90% of Ni; 0.61-1.10% Cr; 0.36-0.75% of Mo; 0.041% -0.055% of Nb; less than or equal to 0.012 percent of Als; 0.015% -0.025% N; 0.0011% -0.0029% of B; 0.01% -0.05% of Co; 0.01-1.00% of Zr, and the balance of Fe and inevitable impurities; the production method comprises smelting, continuous casting, rolling and heat treatment; the steel plate produced by the process technology has excellent low-temperature toughness indexes through chemical component optimization and reasonable design of process parameters. After the steel plate is subjected to quenching and tempering treatment and simulated postweld heat treatment, the-20 ℃ impact absorption energy is kept above 100J.

Description

Thick steel plate for nuclear power station containment equipment module and production method thereof

Technical Field

The invention belongs to the field of metal materials, and particularly relates to a thick steel plate for a nuclear power station containment equipment module and a production method thereof.

Background

Nuclear power is an economical, clean and safe energy source, and compared with traditional thermal power generation, nuclear power generation is higher in safety and more economical than thermal power generation. The AP1000 and the EPR belong to the advanced third-generation pressurized water reactor nuclear power technology and have multiple safety protection systems. The containment vessel is used mainly to control and limit the diffusion of radioactive materials from the reactor, and is the last safety barrier of the nuclear power plant to prevent nuclear radiation. The containment generally comprises two layers, wherein the outer layer is a reinforced concrete shielding structure, the inner layer is a cylindrical independent cylindrical steel container with upper and lower elliptical seal heads, and the cylindrical steel container is also a component of the whole passive containment cooling system.

The steel material used for manufacturing the containment module or the containment system needs to have the following technical requirements: strict and reasonable chemical composition, good internal quality, excellent toughness matching and excellent processing performance. In the practical application process of the material, the single weight of the material, the welding performance of the material and the corrosion resistance of the material must be considered. With the development of nuclear power technology, a modular construction technology is gradually adopted, a good engineering effect is obtained, with the increasing maturity of the modular technology and the accumulation of application experience, the range of modular design construction adopted by the nuclear power station is wider and wider, and the designed modules are larger and larger. At present, more patents are formed for steel for nuclear power at home and abroad:

the related patent applications of the steel for the containment vessel of the nuclear reactor produced at present are as follows:

the patent application number is 201310083274.7 entitled high strength and toughness steel plate for nuclear power station mechanical module supporting piece and manufacturing method thereof, which mainly relates to a production method of the steel plate for the nuclear power station mechanical module supporting piece, and the steel plate comprises the following components: c: 0.08 to 0.22 percent; si: 0.15 to 0.45 percent; mn: 0.60% -1.10%; p is less than or equal to 0.020%; s is less than or equal to 0.015 percent; ni: 0.60% -1.00%; cr: 0.40 to 0.70 percent; cu: 0.15 to 0.55 percent; mo: 0.40% -0.60%; v: 0.020% -0.080%; ti: 0.008 to 0.030 percent; b: 0.0005 to 0.005 percent; al: 0.020-0.050% and the balance of iron and impurities. The patent properly adds alloy elements on the basis of low-carbon content design, so that the tensile strength of the steel reaches over 800 MPa. The steel plate thickness of this patent is 6 ~ 65mm, and the steel plate thickness is lower, can not cover the thickness scope of nuclear power mechanical module completely, and the thermal treatment temperature range of this patent is very big simultaneously, under this temperature range, can cause the structure of steel sheet unstable.

A patent entitled "steel sheet for containment vessel of nuclear power plant of the third generation and method for manufacturing the same" filed by the ji Steel group, ltd, patent application No. 201210282831.3, publication nos. CN 102776441a, C: 0.08-0.12%, Si: 0.15-0.55%, Mn: 0.90-1.50%, P is less than or equal to 0.007%, S is less than or equal to 0.004%, Ni: 0.10-0.50%, Cr: 0.0 to 0.30%, Mo: 0.10-0.35%, V: 0.010-0.050%, Nb: 0.010-0.030%, Ti: 0.008-0.035%, Alt: 0.020-0.050%, N less than or equal to 0.006%, Nb + V less than or equal to 0.08%, and the balance of Fe and inevitable impurities. The steel plate manufactured by the method has the advantages of low carbon content, tensile strength of over 600MPa, 200 ℃ high-temperature resistance, low cost and excellent welding performance. However, the maximum thickness of the steel sheet in the examples in this specification is 45mm, and the specification does not provide a steel sheet simulating the post-weld heat treatment properties and the steel sheet bending properties.

Patent entitled "thick steel plate for nuclear power plant containment vessel and method for manufacturing same" filed by baoshan steel products ltd, patent application No. 201210269122.1, publication nos. CN 102766805a, C: 0.06-0.15%, Si: 0.10-0.40%, Mn: 1.0-1.5%, Mo: 0.10-0.30%, P is less than or equal to 0.012%, S is less than or equal to 0.003%, Alt: 0.015 to 0.050%, Ni: 0.20-0.50%; and V is less than or equal to 0.050%, Ti is less than or equal to 0.030%, Cr is less than or equal to 0.25%, Nb is less than or equal to 0.030%, Ca: 0.0005-0.0050%; the balance being Fe and unavoidable impurities. The thick steel plate for the nuclear power station containment vessel, provided by the invention, has high strength and high toughness, and the base metal and the heat affected zone have good impact toughness under the low temperature condition, so that the thick steel plate is suitable for being applied to the field of manufacturing of the nuclear power station containment vessel. However, the maximum thickness of the steel plate in the claims of the reference is 60mm, and the specification does not provide the high temperature tensile index of 150 ℃ or 200 ℃.

Disclosure of Invention

The invention aims to overcome the problems and the defects and provides a thick steel plate for a nuclear power station containment equipment module and a production method thereof.

The purpose of the invention is realized as follows:

a thick steel plate for a containment equipment module of a nuclear power station comprises the following components in percentage by weight: 0.11% -0.19% of C; 0.19% -0.49% of Si; 1.01-1.39% of Mn; p is less than or equal to 0.010 percent; s is less than or equal to 0.005 percent; 0.61% -0.90% of Ni; 0.61-1.10% Cr; 0.36-0.75% of Mo; 0.041% -0.055% of Nb; less than or equal to 0.012 percent of Als; 0.015% -0.025% N; 0.0011% -0.0029% of B; 0.01% -0.05% of Co; 0.01-1.00% of Zr, and the balance of Fe and inevitable impurities.

The invention has the following design reasons:

(1) c: c is the most effective element for strengthening structural steel, and directly influences the strength, plasticity, toughness, welding performance and the like of steel. Therefore, the steel of the present invention requires the C content in the steel to be controlled in the range of 0.11 to 0.19% when designing the composition.

(2) Si: si is one of five major elements in steel, can play a role in deoxidation and solid solution strengthening, and can promote the growth of columnar crystals in cast steel and reduce the anisotropy of the crystals at the same time, and the Si content is required to be 0.50-0.70%.

(3) Mn: mn is a good deoxidizer and desulfurizer, a certain amount of manganese contained in the steel can eliminate or weaken the hot brittleness of the steel caused by sulfur, and meanwhile, Mn is the most main alloy element in the steel and has great influence on the comprehensive performance of the steel. Therefore, the Mn content in the actual production is controlled to be 1.01-1.39%.

(4) P: p is dissolved in ferrite, the tempering brittleness of steel is increased, the plasticity and the toughness of the steel are obviously reduced, and adverse effects are also caused on welding, so that the lower the content of phosphorus is, the better the phosphorus content is, but the P can improve the strength and the atmospheric corrosion resistance of the steel, and the P in the steel is required to be controlled to be less than or equal to 0.010 percent.

(5) S: sulfide inclusions are easily formed in steel, the impact toughness of the steel is reduced, the welding performance is damaged, the defects of center segregation, looseness and the like are aggravated, and irradiation embrittlement is increased, so that the S is required to be less than or equal to 0.005 percent.

(6) Ni: the Ni element with a certain content can reduce dislocation motion resistance in the steel, and stress in the steel can be relaxed along with the reduction of the dislocation motion resistance, so that the mode of matrix tissue dislocation and substructure is formally changed by the Ni element, the toughness of the steel is improved, and the Ni content in the steel is controlled to be 0.61-0.90%.

(7) Cr: cr can obviously improve the antioxidation of steel in steel, and the steel for the nuclear power station belongs to steel for a nuclear power station safety shell module, requires a steel plate to have certain corrosion resistance, can increase the corrosion resistance, and also can improve the hardness of the steel by a certain amount of chromium, so the invention requires that the Cr content in the steel is controlled to be 0.61-1.10 percent.

(8) Mo: the Cr-Mo alloy system is favorable for the production of modulation steel, and meanwhile, molybdenum is a strong carbide forming element, and when the content is lower, a composite cementite is formed, so that the heat resistance can be improved, and the temper brittleness can be reduced. Therefore, the invention requires that the content of Mo is controlled between 0.36 and 0.75 percent.

(9) Nb: nb can improve the yield strength of steel, reduce the brittle transition temperature, is beneficial to the welding performance of the steel, and is less sensitive to irradiation, so that the Nb content of the steel is required to be controlled to be 0.041-0.055 percent.

(10) And Als: the aluminum plays a certain role in deoxidation in steel making and is beneficial to refining grains. The generation of fine Al2O3 second phase can be used as nucleation particles through proper control, which is beneficial to the overall performance. Therefore, the invention requires that the content of Als is less than or equal to 0.012 percent.

(11) B: b is only one intercrystalline strengthening element, trace B can improve the high-temperature strength of the alloy, and B has strong neutron absorption capacity but has a tendency of slightly promoting temper brittleness. Therefore, the invention requires that the content of the steel B is controlled to be 0.0011-0.0029%.

(12) N: precipitates of NbN and ZrN are formed in microalloyed steel containing Nb and Zr, and are stable in the steel and do not decompose, so that the precipitates have the inhibiting effect on high-temperature deformation, recrystallization and grain growth. Therefore, the content of N added into the steel is controlled to be 0.015 to 0.025 percent

(13) Zr: zr is a strong carbon compound forming element, and the addition of a small amount of Zr has the functions of degassing, purifying and refining grains, thereby being beneficial to the low-temperature toughness of the steel, so that the content of Zr added into the steel is controlled to be 0.01-1.00 percent.

(14) Co: co and Mo are added into the steel at the same time, so that the comprehensive mechanical property of the steel can be improved, and the irradiation embrittlement of the material is caused by overhigh content, so that the content of Co in the steel is controlled to be 0.01-0.05%.

The second technical scheme of the invention provides a production method of a thick steel plate for a containment equipment module of a nuclear power station, which comprises smelting, continuous casting, rolling and heat treatment;

smelting: adding molten iron, scrap steel and other raw materials into a converter or an electric furnace for smelting;

continuous casting: casting the smelted molten steel into a slab through continuous casting;

rolling: the heating temperature of the steel billet is 1200-1250 ℃, and the rolling starting temperature is as follows: 1150-1200 ℃, finishing temperature: 950 ℃ and 1000 ℃.

And (3) heat treatment: after the steel plate is rolled, a quenching and tempering treatment process is adopted to obtain a fine and uniform tempered sorbite structure, and the steel plate has good comprehensive mechanical properties. The specific process comprises the following steps:

the quenching temperature is 870-940 ℃, and the heat preservation time is 3-6 min/mm;

the tempering temperature is 620-680 ℃, and the heat preservation time is 4-10 min/mm.

The invention has the beneficial effects that:

(1) the steel plate produced by the process technology has excellent low-temperature toughness indexes through chemical component optimization and reasonable design of process parameters. After the steel plate is subjected to quenching and tempering treatment and simulated postweld heat treatment, the-20 ℃ impact absorption energy is kept above 100J.

(2) After quenching and tempering and simulated postweld heat treatment (the heat preservation temperature is 600 ℃, and the heat preservation time is as long as 15 hours), the steel grade has good strength and toughness in different states. The tensile strength of the steel plate after the quenching and tempering heat treatment and the simulated postweld heat treatment in normal temperature stretching is more than or equal to 660MPa, and the tensile strength in 150 ℃ high temperature stretching is more than or equal to 590 MPa.

Detailed Description

The present invention is further illustrated by the following examples.

According to the embodiment of the invention, the components are proportioned according to the technical scheme, and smelting, continuous casting, rolling and heat treatment are carried out. The compositions of the steels of the examples of the invention are shown in table 1. The main process parameters of the steel of the embodiment of the invention are shown in Table 2. The properties of the steels of the examples of the invention are shown in Table 3.

TABLE 1 composition (wt%) of steels of examples of the present invention

Examples	C	Si	Mn	P	S	Ni	Cr	Mo	Als	Co	Zr	Nb	N	B
															1	0.11	0.49	1.01	0.009	0.003	0.89	1.01	0.36	0.011	0.01	0.01	0.055	0.015	0.0011
2	0.12	0.19	1.39	0.007	0.004	0.81	0.61	0.41	0.012	0.05	0.10	0.053	0.017	0.0029
															3	0.14	0.25	1.11	0.007	0.004	0.78	0.91	0.49	0.005	0.04	0.39	0.049	0.019	0.0015
4	0.15	0.31	1.21	0.007	0.003	0.71	0.83	0.55	0.006	0.03	0.69	0.045	0.021	0.0025
															5	0.17	0.39	1.28	0.005	0.002	0.65	0.72	0.65	0.009	0.02	0.89	0.043	0.022	0.0019
6	0.19	0.45	1.35	0.003	0.001	0.61	1.09	0.75	0.010	0.01	0.99	0.041	0.025	0.0023

TABLE 2 Main Process parameters of the steels of the examples of the invention

TABLE 3 Properties of steels of examples of the invention

As can be seen from Table 3, after the steel plate is subjected to quenching and tempering, all performance indexes completely meet the requirements, and meanwhile, the steel plate has good performance in the thickness direction, completely meets the Z35 requirement, and completely meets the II-grade ultrasonic flaw detection requirement of the NB/T47013.3 standard.

In order to express the present invention, the above embodiments are properly and fully described by way of examples, and the above embodiments are only used for illustrating the present invention and not for limiting the present invention, and those skilled in the relevant art can make various changes and modifications without departing from the spirit and scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made by the persons skilled in the relevant art should be included in the protection scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. The thick steel plate for the containment equipment module of the nuclear power station is characterized by comprising the following components in percentage by weight: 0.14% -0.19% of C; 0.19% -0.49% of Si; 1.01-1.39% of Mn; p is less than or equal to 0.010 percent; s is less than or equal to 0.005 percent; 0.61% -0.90% of Ni; 0.91-1.10% of Cr; 0.49% -0.75% of Mo; 0.041% -0.055% of Nb; less than or equal to 0.012 percent of Als; 0.015% -0.025% N; 0.0011% -0.0029% of B; 0.01% -0.05% of Co; 0.39-1.00% of Zr, and the balance of Fe and inevitable impurities.

2. A production method of the thick steel plate for the nuclear power station containment equipment module, which is described in claim 1, comprises the steps of smelting, continuous casting, rolling and heat treatment; the method is characterized in that:

rolling: the heating temperature of the steel billet is 1200-1250 ℃, and the rolling starting temperature is as follows: 1160-1200 ℃, and finishing temperature: 950 ℃ and 990 ℃;

and (3) heat treatment: quenching and tempering are adopted, and the specific process comprises the following steps:

the quenching temperature is 870-890 ℃, and the heat preservation time is 3-6 min/mm;

the tempering temperature is 620-680 ℃, and the heat preservation time is 7-10 min/mm.