Extra-thick container steel plate with excellent low-temperature impact toughness at center

Abstract

The invention relates to an extra-thick container steel plate with excellent low-temperature impact toughness at the center. The production thickness of the extra-thick container steel plate is 60 to100 mm. The extra-thick container steel plate comprises the following chemical components: 0.13-0.20% of C, less than or equal to 0.40% of Si, 1. 00-1.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.01-0.05% of Als, less than or equal to 0.080% of Nb+V+Ti, 0.20-0.50% of Ni, less than or equal to 0.30% of Cu, less than or equal to 2 ppm of H, and the balance of Feand inevitable impurity elements, and at the same time, the conditions that the mass percent of CEV is less than or equal to 0.43%, and w(Nb+V+Als) / w(Ti) is larger than or equal to 3 and less than orequal to 8 are met. A structure near the surface of the steel plate is tempered sorbite, and a structure at a part that is 1 / 4 of the steel plate thickness and a structure at a part that is 1 / 2 of the steel plate thickness are bainite. The lateral impact energy -50 DEG C KV2 at a part that is 1 / 4 of the plate thickness is larger than or equal to 150 J; and the lateral impact energy -50 DEG C KV2at a part that is 1 / 2 of the plate thickness is larger than or equal to 80 J. A manufacturing method comprises the following manufacturing processes of molten iron pretreatment, converter smelting, ladle furnace refining, vacuum degassing treatment, continuous casting, casting blank capped cooling, casting blank heating, controlled rolling, controlled cooling, stacking for slow cooling, and tempering. An online quenching process is adopted to ensure that the steel plate has excellent strength and toughness, and at the same time, online quenching can significantly shorten the delivery cycle.

Description

Technical field [0001] The invention belongs to the technical field of iron-based alloys. Background technique [0002] In recent years, various petrochemical and natural gas projects have been implemented at home and abroad, and the demand for large-scale reaction vessels or storage tanks has increased significantly. Quenched and tempered steel plates have become more and more popular due to their good strength and toughness matching, especially as the equipment continues to become larger , High-parameter development, while ensuring the safe and stable operation of the equipment, good core low-temperature impact toughness and weldability are particularly critical. In summary, the development of container steel plates with excellent low-temperature toughness in the weldable core that can be mass-produced and can meet the requirements of large-scale energy equipment manufacturing has broad market prospects. [0003] The patent (CN107267857A) applied for a 07MnNiMoDR ​​steel plate a...

AI Technical Summary

Problems solved by technology

[0006] To sum up, most of the existing quenched and tempered high-strength toughness steel plates are produced by the traditional off-line quenching process. Demand for large-scale and high-parameterized development of chemical energy equipment

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