Quenched and tempered steel plate with yield strength being 420 MPa grade for building structure and production method of quenched and tempered steel plate

Abstract

The invention relates to a quenched and tempered steel plate with the yield strength being 420 MPa grade for a building structure and a production method of the quenched and tempered steel plate. The component design that Nb and Ti microalloying treatment is conducted on the basis of a Fe-Mn-C system is adopted, and the steel plate material is prepared from the chemical components including 0.13%-0.18% of C, 0.20%-0.50% of Si, 1.40%-1.70% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, less than or equal to 0.30% of Cr, less than or equal to 0.30% of Mo, less than or equal to 0.30% of Ni, less than or equal to 0.30% of Cu, 0.020%-0.050% of Al, less than or equal to 0.015% of V, 0.025%-0.050% of Nb, 0.010%-0.020% of Ti, less than or equal to 0.006% of N and the balance Fe and inevitable impurity elements. The production process comprises the following steps that raw materials are smelted in a converter, refined outside the converter and refined in an RH furnace in sequence to obtain molten steel with higher purity, the molten steel is poured to form a steel billet being 370 mm-450 mm, then reasonable steel billet heating, rolling, on-line direct quenching and tempering heat treatment technologies are adopted, and the steel plate material with the yield strength being 420 MPa grade is suitable for large-scale steel structure constructional engineering such as high-rise buildings, large-span stadiums, airports, exhibition centers and industrial factory buildings is obtained.

Description

technical field [0001] The invention relates to a quenched and tempered steel plate for building structures with a yield strength of 420 MPa and a production method thereof. It belongs to the technical field of the metallurgical industry. Background technique [0002] With the rapid development of my country's economy, the selected steel plate materials for large-scale steel structure construction projects such as high-rise buildings, long-span stadiums, airports, exhibition centers and industrial plants are gradually upgraded to a yield strength of 420MPa or even higher. In GB / T 19879 standard for steel plates, the maximum thickness has been expanded to 200mm, and stricter material carbon equivalent Ceq, welding crack sensitivity coefficient Pcm control requirements have been added, and the yield strength thickness effect, yield ratio, elongation and Performance indicators such as minimum impact absorption energy put forward stricter requirements, and the production difficul...

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved by the present invention is to provide a quenched and tempered steel plate for building structures with a yield strength of 420 MPa and its production method in view of the above-mentioned prior art, and to solve the problem that the yield strength of the normalizing heat-treated Q420GJ with a thickness of 50 mm to 100 mm is difficult to reach the standard asked questions

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