Method for improving low-temperature impact toughness of high strength thick steel plate

Abstract

The invention discloses a production method for improving the low-temperature impact toughness of a high strength thick steel plate, and belongs to the technical field of medium and thick steel plate production. The steel comprises the following chemical compositions: 0.05 to 0.15 percent of C, 0.15 to 0.40 percent of Si, 0.90 to 1.60 percent of Mn, less than 0.01 percent of P, less than 0.01 percent of S, 0.10 to 0.80 percent of Ni, 0.1 to 0.5 percent of Mo, 0.0008 to 0.0015 percent of B, 0.01 to 0.06 percent of microalloy element Nb, 0.01 to 0.07 percent of V, 0.01 to 0.03 percent of Ti and the balance of Fe; the thick steel plate is produced by soft reduction technology in a continuous casting process under the condition that a compression ratio is less than 4.0; and by a heat treatment process which comprises the steps of quenching, quenching and tempering, the texture of the steel plate after double quenching is controlled to be a hybrid texture with a hard phase and a soft phase, and the requirements on steel plate strength and low-temperature toughness are met at the same time. Under a small compression ratio, the thick steel plate has the performance equivalent to that of a thin steel plate by the combination of the heat treatment process and texture control; and compared with the methods such as die casting, forging and the like, the method is simple and feasible, and has high yield and low production cost.

Description

technical field [0001] The invention belongs to the technical field of steel plate production, and in particular provides a method for improving the impact toughness of high-strength thick steel plates. The method of light reduction and two-stage quenching and tempering heat treatment is mainly used to improve the impact toughness of the high-strength steel plate and the impact toughness of the core under the condition that the compression ratio is less than or equal to 3. Background technique [0002] Usually, when the compression ratio of the steel plate is less than 4, the impact toughness of the steel plate deteriorates due to deformation penetration and insufficient grain refinement during the rolling process, especially the toughness of the core of the steel plate. In high-strength steel plates, especially steel plates used in complex stress situations such as multi-directional pressure, the impact toughness in the thickness direction of the steel plate is strictly req...

AI Technical Summary

Problems solved by technology

[0004] In the production of high-strength thick steel plates, die casting can be used to ensure the compression ratio of steel plates, but die casting has the characteristics of low yield,

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