Hot rolled sheet with tensile strength equal to or higher than 800 MPa and prepared by direct rolling of sheet billet and producing method thereof

Abstract

Disclosed is a hot rolled sheet with the tensile strength equal to or higher than 800 MPa and prepared by direct rolling of a sheet billet. The hot rolled sheet comprises, by weight, 0.030-0.071% of C, 0.21-0.42% of Si, 0.5-1.5% of Mn, 0.04-0.15% of Ti, 0.12-0.41% of Mo, 0.02-0.10% of Nb, 0.13-0.35% of Cr, no more than 0.020% of P, no more than 0.010% of S and no more than 0.010% of N. A producing method includes the steps of smelting and continuous casting to form the billet, heating of the casted billet, precision rolling by seven machine frames, laminar flow cooling, and coiling. According to the hot rolled sheet with the tensile strength equal to or higher than 800 MPa and prepared by direct rolling of the sheet billet and the producing method thereof, by combining the characteristics that the solidification speed of the sheet billet continuous casting is fast and the texture is uniform, and matching with TMCP, Mo is added on the basis of the Ti-Nb composite micro-alloying, the tensile strength of a steel plate can reach 800 MPa under the condition of hot rolling, and quenching-and-tempering heat treatment can be omitted; in addition, a hot rolled material with the thickness of 0.8 mm can be produced, and a cold rolled product of the corresponding specification can be replaced directly; and according to the hot rolled sheet with the tensile strength equal to or higher than 800 MPa and prepared by direct rolling of the sheet billet and the producing method thereof, the producing process is simple, the producing efficiency is high, and the producing cost is low.

Description

technical field [0001] The invention relates to a high-strength hot-rolled steel used in the field of mechanical engineering and a production method thereof, specifically belonging to a hot-rolled sheet with a yield strength ≥ 800 MPa and a production method thereof, specifically a hot-rolled sheet with a yield strength ≥ 800 MPa directly rolled by a thin slab and its production method method. The invention is more suitable for manufacturing structural parts with complex cross-sections and higher requirements on formability. Background technique [0002] In recent years, with the trend of low-cost, lightweight, and high-quality development in the field of mechanical engineering, the demand for thin-gauge, ultra-high-strength steel will increase day by day. Such as concrete pump truck boom, truck crane telescopic boom, crawler crane pull plate, etc., its key components have been required to be made of ultra-high-strength thin steel plates to reduce dead weight, improve equip...

AI Technical Summary

Problems solved by technology

This type of steel has super high strength and relatively poor formability, and is mainly used to manufacture anti-collision and load-bearing parts of automobiles

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