Easy-to-weld ultra-thick steel plate with high strength and high toughness suitable for minus 60 DEG C and manufacturing method thereof

Abstract

The invention relates to an easy-to-weld ultra-thick steel plate with high strength and high toughness suitable for minus 60 DEG C. The steel plate comprises the chemical ingredients of 0.05% to 0.10% of C, 0.2% to 0.3% of Si, 1.3% to 1.6% of Mn, 0.02% to 0.04% of Al, 0.03% to 0.05% of Nb, 0.03 to 0.05% of V, 0.1% to 0.3% of Cr, 0.1% to 0.4% of Ni, 0.1% to 0.3% of Mo, 0.1% to 0.3% of Cu, 0.01% to 0.02% of Ti, 0% to 0.015% of P, 0% to 0.002% of S, and 0% to 0.007% of N; the carbon equivalent is not larger than 0.43, and Pcm is not larger than 0.20. According to the steel plate, the thickness ranges from 70 mm to 120 mm, the yield strength is 460 MPa or more, and under the temperature of minus 60 DEG C, both the Charpy impact energy at the position, with the thickness one quarter that of the thickness of the steel plate, of the steel plate and the Charpy impact energy at the position, with the thickness one half that of the thickness of the steel plate, of the steel plate are larger than or equal to 100 J. The easy-to-weld ultra-thick steel plate with high strength and high toughness is made through the steps of KR hot metal pretreatment, converter smelting, ladle furnace refining, RH vacuum degassing, continuous casting, slow cooling, casting blank heating, rolling, straightening, pile slow cooling, quenching, tempering and the like.

Description

technical field [0001] The invention belongs to the field of manufacturing low-temperature special steel plates, and in particular relates to a 460MPa grade easy-to-weld high-strength and high-toughness extra-thick steel plate that can serve in an environment of -60°C. Background technique [0002] With the continuous increase in the strength of structural steel, 460MPa low-alloy high-strength steel plate has become one of the most important engineering structural materials, and is widely used in major projects such as marine engineering, shipbuilding, high-rise building structures, bridges, rail transit, and automobile manufacturing. . At present, in addition to the requirements for steel plates to meet the strength requirements, there are more stringent requirements for low-temperature toughness and weldability of materials according to different use environments, especially in alpine regions. It is required that the Charpy impact energy at -60°C is above 100J, and the C ...

AI Technical Summary

Problems solved by technology

[0005] There are also some domestic patents that use the quenching and tempering process to produce 460MPa grade steel plates. The invention patent of patent number CN 104894490A proposes high-strength extra-thick steel plates and their manufacturing methods. The content is 0.12-0.14%, and at the same time, it only meets the impact energy of -20℃﹥27J

Does not meet the conditions of easy solderability (C content ≤ 0.10%) and low temperature conditions of -60°C

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