Low-yield-ratio high-toughness TMCP type bridge steel plate and production method thereof

Abstract

The invention discloses a low-yield-ratio high-toughness TMCP type bridge steel plate and a production method thereof. The steel comprises the following chemical components in percentage by weight of0.07 to 0.12% of C, 0.11 to 0.18% of Si, 1.42 to 1.52% of Mn, 0.008 to 0.015% of P, 0.002 to 0.010% of S, 0.08 to 0.16% of Cr, 0.012 to 0.018% of Nb, 0.008 to 0.016% of Ti, 0.020 to 0.050% of Alt, 0.002 to 0.005% of N, the balance iron and impurities and 0.350 to 0.369% of carbon equivalent. According to the production method, a continuous casting billet is subjected to heating, controlled rollingincluding recrystallization zone rolling, temperature waiting and non-recrystallization zone rolling and controlled cooling including ferrite zone cooling, temperature waiting and bainite zone cooling, and the bridge steel plate is manufactured. The obtained bridge steel plate is low in yield ratio, high in toughness and excellent in welding performance.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and relates to a production method of a low-yield-ratio high-toughness TMCP bridge steel plate and a low-yield-ratio high-toughness TMCP bridge steel plate prepared by the production method. Background technique [0002] With the rapid development of expressways and high-speed railways in my country, the rapid development of steel bridge manufacturing industry has been promoted. Steel bridges are developing toward multi-functional, multi-lane, heavy-load, long-span and other directions while satisfying functionality. Structural steel for bridges is mainly used in key projects such as the construction of railways, highways, sea-crossing, and river-crossing bridges. Due to the particularity of the use environment, it has strict requirements on comprehensive performance, such as low yield ratio, good weldability, high toughness, etc. [0003] In order to improve the overall performanc...

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Problems solved by technology

[0005] The object of the present invention is to provide a kind of production method of low yield strength ratio high tenacity TMCP type bridge steel plate, and a kind of low yield strength ratio high toughness TMCP type bridge steel plate prepared by this production method, in optimizing chemical composition design scheme At the same time, a new TMCP process control scheme is adopted to reduce the addition of precious alloy elements, without additional off-line heat treatment, and to obtain bridge steel plates with low yield ratio, high toughness and excellent welding performance, which solves the problem of high production cost and production cost. Problems such as long process, slow production pace, and long cycle

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