High-strength high-toughness pressure vessel steel plate and preparation method thereof

Abstract

The invention discloses a high-strength high-toughness pressure vessel steel plate which comprises the following chemical components in percentage by mass: 0.160-0.210% of C, less than or equal to 0.55% of Si, 1.58-1.80% of Mn, less than or equal to 0.012% of P, less than or equal to 0.0025% of S, less than or equal to 0.45% of Ni, less than or equal to 0.020% of Al, 0.13-0.18% of V, 0.0080-0.0180% of N, less than or equal to 0.0005% of Mg and the balance of Fe and inevitable impurities. The V-Ni-N alloy system is adopted, a heterogeneous core fine dispersion effect formed by introducing Mg and the means of controlling the components Al, N and V are combined, and the medium / low-temperature heating system and the crystallization controlled rolling technology are adopted, so that the steel can achieve excellent low-temperature high strength and high toughness, can effectively solve the technical problem that the conventional pressure vessel steel plate difficultly meets the low-temperature service requirement, and has important popularization and application value.

Description

technical field [0001] The invention belongs to the field of low-alloy steel manufacturing, and in particular relates to a high-strength and high-toughness pressure vessel steel plate and a preparation method thereof. Background technique [0002] High-toughness pressure vessel steel plates are often used in low-temperature, impact-loaded environments, and sometimes, such steel plates are used in industrial devices that work in extreme environments such as base environments: such as railway tank cars, tank containers for ocean ships, extremely low Automobile tankers, spherical tanks, etc. all need to ensure the low-temperature toughness in the service environment while ensuring the strength of the material. For this reason, a low-alloy high-strength high-toughness steel with V microalloying as the main microalloy was designed, which not only solved the mismatch between high strength and low-temperature toughness of the steel plate, but also made the inventive material change...

AI Technical Summary

Problems solved by technology

[0003] Patent CN 102618784 B discloses a "60-kilogram low-cost, high-toughness steel plate and its manufacturing method", which uses V-N microalloying. Although the steel is denatured with low Al and CaSi, the composite inclusions of Ca are higher than those of Mg. The size of the composite oxide is large, and the size of the inclusions directly affects the level of impact toughness, and the use of normalizing + tempering heat treatment process significantly increases the production cost

Patent CN 102719737 B discloses a "normalized high-strength and tough steel plate with a yield strength of 460MPa and its manufacturing method". However, during the steelmaking process, it is easy to form long chain-shaped alumina inclusions in the steel, which will damage the low-temperature toughness of the steel, and it is difficult to meet the low-temperature use requirements of the invented steel

[0004] The Chinese invention patent with the publication number CN 107099746 A discloses "a high-strength low-alloy steel plate for normalizing pressure vessels and its production method". It adopts V-Nb-N alloy design, and there is no Al used for deoxidation in the steel If it is limited, it is easy to form long chain-shaped alumina inclusions in the steel during the steelmaking process, which will damage the low-temperature toughness of the steel, and it is difficult to meet the low-temperature use requirements of the invented steel

The Chinese invention patent with the publication number CN 103233160 A discloses "a normalizing container steel with a yield strength of 460MPa and its manufacturing method". In this process, TiN inclusions with a size of 5-15 μm are formed when the molten steel solidifies, and the size of TiN inclusions cannot be reduced during subsequent rolling and heat treatment. Furthermore, the high Al content in the steel is easy to form in the steelmaking process. , forming long chain-shaped alumina inclusions in the steel, the above two factors will damage the low-temperature toughness of the steel, and it is difficult to meet the low-temperature use requirements of the invention steel

[0005] The Chinese invention patent of CN 103233160 A discloses "a 17MnNiVNbDR steel plate for tank trucks and its production method". The size of the composite oxide is larger than that of Mg. Moreover, the Al content in the steel is high, and it is easy to form long chains of alumina inclusions in the steel during the steelmaking process. The above two factors will damage the low temperature toughness of the steel. Difficult to meet the low temperature requirements of the invention steel

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