Profiled bar steel with tensile strength higher than or equal to 1600 MPa and production method

Abstract

The invention discloses profiled bar steel with tensile strength higher than or equal to 1600 MPa. The profiled bar steel comprises, by weight, 0.25%-0.33% of C, 1.5%-2.0% of Si, 2.6%-3.2% of Mn, smaller than or equal to 0.02% of P, smaller than or equal to 0.01% of S, 0.01%-0.10% of Als, smaller than or equal to 0.005% of N, not larger than 1.0% of Cr, not larger than 1.0% of Ni, not larger than 0.05% of Nb, not larger than 0.5% of V, and the balance Fe. The process comprises the following steps of conducting smelting and casting into a slab; heating a casting blank; carrying out rough rolling; carrying out finish rolling; performing air cooling after coiling; carrying out austenitizing; conducting quenching treatment; conducting aging treatment; performing coiling and air-cooling to room temperature; and carrying out uncoiling again, flattening, slitting, rolling and forming. Nb / V (C, N) is formed in a matrix structure by adding Nb and V, the Nb / V (C, N) plays a pinning role in a soaking stage of quenching and tempering heat treatment, the growth of austenite is hindered, the formation of a refined austenite phase is promoted, and the elongation is improved from less than or equal to 7% to more than or equal to 10% under the condition that the yield strength is higher than or equal to 1200 MPa and the tensile strength is higher than or equal to 1600 MPa.

Description

technical field [0001] The invention relates to ultra-high-strength steel for automobiles and buildings and a production method thereof, and specifically belongs to the steel for special-shaped bar manufacturing with a tensile strength ≥ 1600 MPa and a production method thereof. Background technique [0002] In recent years, my country has actively deployed carbon peaking and carbon neutralization work to effectively promote green and low-carbon development. Steel is the basic material of modern production and manufacturing, and it is also the industry with the largest carbon emissions in the existing manufacturing industry; how to lead the green development of the steel industry through the coordination of upstream and downstream industries has important social value. Optimizing and improving the strength and application performance of steel materials, realizing lightweight components, and effectively reducing the use of steel materials are the best ways to promote the carb...

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Problems solved by technology

[0006] The raw materials for the above-mentioned high-strength section steel are thick steel billets, which require repeated molding and heat treatment, and the process is relatively complicated; and the strength is still low, which needs to be studied and improved

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