On-line quenching complex-phase structure hot-rolled wear-resistant steel and preparation method thereof

Abstract

The invention relates to on-line quenching complex-phase structure hot-rolled wear-resistant steel. The on-line quenching complex-phase structure hot-rolled wear-resistant steel comprises the following chemical components in percentage by weight: 0.14-0.18% of C, 1.5-2.0% of Mn, 0.20-0.35% of Cr, 1.0-1.3% of Si, 0.02-0.04% of Nb and the balance Fe and inevitable impurities. The preparation method comprises the working procedures of converter smelting, slab continuous casting, slab heating, controlled rolling, controlled cooling and coiling. In the slab heating process, a steel billet is heated to 1,200-1,280 DEG C, heat preservation is conducted for 3-4 h, the furnace discharging temperature is 1,150-1,200 DEG C, and the homogenization quality of the steel billet is guaranteed; and in the controlled cooling process, a sectional cooling process is adopted, namely, firstly, a hot-rolled plate is subjected to water cooling to 600-700 DEG C for intercooling for 5-8 s, then, a steel plate is subjected to water cooling to 100-200 DEG C, and finally, coiling is carried out. The Brinell hardness of the produced hot-rolled wear-resistant steel is larger than or equal to 400 HBW, the tensile strength is larger than or equal to 1300 MPa, the yield strength is larger than or equal to 900 MPa, the ductility is 10-15%, the cold bending performance meets the condition that D is equal to 3a, 120-degree qualification is achieved, and the impact energy at the temperature of-40 DEG C is larger than or equal to 65 J; a microstructure is an austenite + ferrite + martensite three-phase structure, and the ferrite content is 12%-18%; and the technological process is simple and the production cost is low.

Description

technical field [0001] The invention relates to the technical field of production of hot-rolled wear-resistant steel, in particular to a hot-rolled wear-resistant steel with on-line quenching multi-phase structure and a preparation method thereof. Background technique [0002] On-line quenching hot-rolled wear-resistant steel is a wear-resistant steel product that does not require quenching and tempering. The structure of the product is composed of ferrite + retained austenite + martensite or bainite. The product has a process flow Short, low cost, long service life and other characteristics, widely used in mixer trucks, dump trucks, pump trucks, wear-resistant box steel and other fields. Along with the development trend of national automobile lightweight, this series of products has gradually become one of the key products for commercial vehicle lightweight upgrading and transformation. With the development of research on hot-rolled wear-resistant steel, some problems have...

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Problems solved by technology

However, the alloy content in the application of the present invention is relatively high, which leads to high cost and affects the application properties such as weldability of wear-resistant steel plates.

[0004] The Chinese patent application of 202010300619.X discloses "a 6~8mm TMCP online quenching low yield ratio high strength wear-resistant steel NM400 coil and its production method", its composition mass percentage: C: 0.18~0.22%, Si: 0.30 ~0.50%, Mn: 1.30~1.45%, P: ≤0.012%, S: ≤0.003%, Nb: 0.015~0.025%, Ti: 0.010~0.025%, Cr: 0.25~0.40%, B: 0.0005~0.0020% , Ca: 0.0010~0.0030%, Al: 0.020~0.050%, the wear-resistant steel is obtained through slab continuous casting-rough rolling-finish rolling-cooling-coil to obtain yield strength ≥ 1000MPa, tensile strength ≥ 1450MPa , yield ratio ≤ 0.70, elongation ≥ 11.0%, -20 o C wear-resistant steel with impact energy ≥ 56J; however, the structure in the present invention is composed of two phases of ferrite + martensite, and there is no austenite phase to provide enhanced plasticization during deformation through the TRIP effect, and at the same time for ferrite The content is not accurately controlled;

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