A 600mpa high-strength hot-rolled structural steel and its manufacturing method

Abstract

The invention discloses a kind of 600Mpa-grade high-strength hot continuous rolling structural steel and a manufacturing method thereof. The structural steel comprises the following chemical compositions in percentage by weight: 0.14-0.24% of C, less than or equal to 0.50% of Si, 0.5-1.5% of Mn, less than or equal to 0.020% of P, less than or equal to 0.010% of S, 0.04-0.15% of Ti, 0.0005-0.003% of B, less than or equal to 0.05% of Al, and the balance of Fe and unavoidable impurities. According to the composition design, through molten-iron deep desulphurization, external refining, slab preparation by continuous casting, slab reheating, controlled rolling, controlled cooling, and rolling, the structural steel disclosed by the invention is obtained, the yield strength is greater than or equal to 600 MPa, the tensile strength is greater than or equal to 650 MPa, the percentage of elongation is greater than or equal to 16%, and the impact energy at the temperature of 20 DEG C is greater than or equal to 100J, and the structural steel has a good cold-bent forming performance.

Description

technical field [0001] The invention belongs to the field of low-alloy steel manufacturing, and in particular relates to a 600MPa high-strength hot-rolled structural steel and a manufacturing method thereof. Background technique [0002] The application of high-strength steel can significantly reduce the weight of the components and the self-weight of the equipment, thereby reducing the fuel consumption of the equipment and improving the working efficiency of the equipment. One or more methods such as fine-grain strengthening, precipitation strengthening, solid solution strengthening, and phase transformation strengthening can be used to improve the strength of structural steel. [0003] At present, there are two main categories of 600MPa high-strength structural steel. One is low-carbon or ultra-low-carbon bainite steel. By adding a certain amount of alloying elements Mo, Mn, Cr, Ni and B, etc., the steel plate forms a structure dominated by low-carbon bainite, so that the...

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Problems solved by technology

[0004] Chinese patent CN101153371A discloses a 700MPa-level hot-rolled steel plate, which mainly improves the strength of the steel plate through the precipitation strengthening of Nb and Ti. The content of precious elements such as Nb and Mo in the steel is relatively high, and the cost of the steel plate is relatively high.

This patent has low C content and high content of elements such as Nb, Mn and Cr, resulting in a relatively high cost of the steel plate

[0006] Chinese patent CN101285156A discloses a Ti precipitation-strengthened bainitic steel. The content of alloy elements Cr and Mn in the steel is relatively high, the cost of the steel plate is relatively high, and the high alloy content will have certain disadvantages to its weldability influences

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