Low-carbon equivalent weight high-strength thick steel plate with excellent low-temperature toughness and manufacture method

Abstract

The invention discloses a low-carbon equivalent weight high-strength thick steel plate with excellent low-temperature toughness and a manufacture method. The steel plate comprises the following chemical components in percentage by weight: 0.090-0.120 percent of C, 1.20-1.60 percent of Mn, 0.10-0.40 percent of Si, not more than 0.015 percent of P, not more than 0.005 percent of S, 0.010-0.030 percent of Nb, 0.010-0.030 percent of V, 0.020-0.035 percent of Al and the balance of Fe and unavoidable impurities. In the rolling process, the heating temperature of a continuous casting blank with the thickness of 220-260mm is 1,200-1,240 DEG C, the heat preservation time is 240-270 minutes, and the discharge temperature is 1,180-1,220 DEG C; and the rolling control at two phases is adopted, the laminar flow cooling is adopted after rolling, the final cooling temperature is 625-725 DEG C, the cooling rate is 5-10 DEG C / s, and the high-temperature offline temperature is 400-450 DEG C. The thick steel plate has low carbon equivalent weight, favorable comprehensive mechanical performance, excellent low-temperature impact toughness, no heat treatment and low production cost and adopts a rolling and cooling control process.

Description

technical field [0001] The invention belongs to the field of metallurgy and relates to the production of a thick steel plate, in particular to a low-carbon equivalent high-strength thick steel plate with excellent low-temperature toughness and a manufacturing method. Background technique [0002] As my country's railway bridges, high-rise buildings, pressure vessels and other engineering structures are developing towards large-scale, high safety, and good integrity, the requirements for the mechanical properties and performance of high-strength thick steel plates are constantly increasing, especially for such The steel plate has excellent low-temperature impact toughness and good welding performance. There are already low-alloy high-strength thick steel plate production technologies at home and abroad, and a higher carbon content design is often adopted. For example, the carbon content is 0.13-0.20%, so that the carbon equivalent is high. The low-temperature impact toughness a...

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Problems solved by technology

[0002] As my country's railway bridges, high-rise buildings, pressure vessels and other engineering structures are developing towards large-scale, high safety, and good integrity, the requirements for the mechanical properties and performance of high-strength thick steel plates are constantly increasing, especially for such The steel plate has excellent low-temperature impact toughness and good welding performance. There are already low-alloy high-strength thick steel plate production technologies at home and abroad, and a higher carbon content design is often adopted. For example, the carbon content is 0.13-0.20%, so that the carbon equivalent is high. The low-temperature impact toughness and welding performance of the steel plate deteriorate. In order to improve the low-temperature toughness of the high-strength thick steel plate, the post-rolling normalizing heat treatment method is often used, which increases energy consumption and production costs.

There are also controlled rolling and controlled cooling production technologies for low-carbon micro-alloyed high-strength thick steel plates at home and abroad. Generally, lower carbon content is designed, such as carbon content of 0.05-0.09%, and higher micro-alloying elements are added, such as adding at the same time 0.03-0.05% Nb, 0.03-0.06% V and 0.010-0.020% Ti improve the low temperature toughness and welding performance, but increase the consumption of alloy resources and production costs

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