900Mpa heavy-gauge and high-toughness hot rolled steel strip and preparation method thereof

Abstract

The invention provides a 900Mpa heavy-gauge and high-toughness hot rolled steel strip and a preparation method thereof, and belongs to the field of structural steel. The steel strip comprises chemicalcomponents in percentage by mass as follows: 0.06%-0.08% of C, 0.15-0.18% of Si, 1.4%-1.6% of Mn, smaller than or equal to 0.012% of P, smaller than or equal to 0.008% of S, 0.8%-1.2% of Cr, 0.005%-0.012% of B, 0.01%-0.03% of Ti and the balance of Fe and inevitable impurities. According to preparation of the steel strip, the product is obtained through smelting-casting, hot rough rolling, hot finish rolling, cooling and coiling. By means of reasonable component design and the controlled rolling and controlled cooling process, yield strength of the steel strip can reach 900 MPa, and the steelstrip is used for replacing a steel plate of the same level obtained with a TMCP and tempering process or a heat treatment process.

Description

technical field [0001] The invention belongs to the field of structural steel, and in particular relates to a 900MPa-level thick and high-toughness hot-rolled steel strip and a preparation method thereof. Background technique [0002] With the continuous improvement of the mechanization level of the coal mining machinery industry, the demand for high-end hydraulic supports continues to increase. In order to meet the requirements of high strength and high reliability of the support, and at the same time reduce the weight of the support as much as possible to facilitate underground transportation and installation, the requirements for the strength and toughness of the steel used for the support are getting higher and higher. At present, the strength level of the steel used for the support has been raised from the yield strength of 600MPa and 700MPa to the yield strength of more than 900MPa. At the same time, higher requirements are put forward for the toughness of the steel, e...

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Problems solved by technology

[0004] Compared with the controlled rolling and controlled cooling process, the heat treatment process not only leads to an increase in production costs, but also the low-temperature impact toughness of the physical steel plate is generally low, which makes it difficult to meet the high-standard product quality requirements of downstream users. Low-cost high-toughness high-strength steel products

[0005] Chinese patent CN102699031A discloses a 900MPa-grade high-toughness low-alloy steel and its manufacturing method. In order to meet the performance requirements of a yield strength of 900MPa, alloy elements such as Ni, Cu, Nb, Mo, and V are added to the design of the alloy composition, resulting in The cost of steel plate alloys has increased significantly

At the same time, the process it adopts is TMCP+off-line tempering, which must be tempered after the controlled rolling and controlled cooling process, which increases the process flow and manufacturing cost, and the composition design and process route of the product cannot meet the requirements of low cost and high performance

[0006] Chinese patent CN103526111A discloses a hot-rolled steel strip with a yield strength of 900 MPa and its preparation method. Al

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