Hot rolled steel sheet

Abstract

The present invention provides a hot rolled steel sheet, comprising by weight: 0.002-0.004% of C, 0.015-0.03% of N, 0.09-0.1% of Cu, 0.15-0.2%of Cr, 0.10-1.80% of Mn, 0.11-0.14% of Ti, 0.16-0.18% of Zr, P <= 0.1%, Si <= 1.0%, S <= 0.1%, Al <= 0.1%, and the balance being Fe and unavoidable impurities. The surface oxide layer of the steel sheet has an average thickness of less than 10 [mu]m, the content of Fe3O4 in the oxide layer is greater than 90%, grain size is of 5.5-6.5 grade, the grain size is 15-25 [mu]m, the volume fraction of ferrite is greater than 90%, the yield strength is less than 210 MPa, the tensile strength is less than 300 MPa, and the elongation is higher than 40%. The present invention can reduce the phase transformation point Ar3 from austenite to ferrite, reduce the coiling temperature, and improve the surface and edge quality of a continuous casting slab, and has the advantages of simple preparation method, low production cost, stable product quality and good stamping property.

Description

technical field [0001] The invention relates to a hot-rolled steel plate. Background technique [0002] With the rapid development of my country's metallurgical industry, hot-rolled plates and strips have been widely used in various industries, and the output of hot-rolled plates and strips is also increasing. The successive introduction and commissioning of conventional hot rolling production line (CSP) and multiple thin slab continuous casting and rolling (TSCR) production lines has not only promoted the increase of plate and strip ratio, but also led to a substantial increase in cold-rolled plate production. Therefore, many enterprises have integrated hot rolling production line (CSP) or TSCR production line and cold rolling production line into a complete industrial production process. However, due to their own process characteristics, the TSCR or CSP production line makes the yield strength of hot-rolled coils significantly higher than that of traditional hot-rolled st...

AI Technical Summary

Problems solved by technology

The negative impacts of the above-mentioned process technology on the preparation of hot-rolled coils are as follows: 1) It is easy to form thicker oxide scales at the high-temperature coiling surface of the hot-rolled coils, which leads to a significant decline in the surface quality of the coils

2) Due to the high coiling temperature of the strip, the service life of the coiler is reduced

3) Due to the influence of high temperature coiling, the coil often has the possibility of collapsing, and the defect of surface cross-folding is prone to appear when uncoiling

[0004] In the current rolling method, no effective solution to overcome the above defects has been found