High-strength hot rolled steel plate and manufacturing method thereof

Abstract

The invention discloses a high strength hot rolled structure steel plate, which belongs to the technical field of the metal structure material. In the invention, an Nb microalloying element is added into low carbon and high manganese clean steel, and also Ca in minute quantities is added. Simultaneously, the invention also discloses the manufacturing method of the steel plate, the manufacturing method comprises the steps that the converter smelting and refining, continuous caster protecting casting, and rolling control and cooling control process is adopted, through the thinning strengthening and precipitation strengthening of the crystal grain, the hot tandem rolled coiled sheet with pure steel quality, good combined property and uniform and fine grain size can be obtained, the steel plate not only has high strength, but also has very high toughness and superior cold forming performance, and the structure requirement of the vehicle can be met.

Description

technical field [0001] The invention belongs to the technical field of metal structural materials, and relates to continuous hot-rolled metal strips. More specifically, the invention relates to a high-strength hot-rolled structural steel plate for automobile structures. At the same time, the invention also relates to a manufacturing method of the high-strength hot-rolled structural steel plate. Background technique [0002] At present, the high-strength hot-rolled steel sheets used in the production of automobile structures at home and abroad are classified according to their chemical composition, including C-Mn steel and Nb, V, Ti single micro-alloyed steel or composite micro-alloyed steel. According to the strengthening method, there are Solid solution strengthening, precipitation strengthening and structural strengthening. Steels with different composition and structure types have different mechanical properties and are suitable for different application fields. The fol...

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Problems solved by technology

[0003] Chinese Patent Publication No. CN1676233A discloses a production process invention patent of thin slab C-Mn high-quality high-strength plate and strip steel. Solid solution strengthening and increasing the pearlite content to obtain pearlite strengthening and solid solution strengthening of Mn to obtain a tensile strength of 530MPa~550MPa, calculated according to CE=C+(Mn+Si) / 6, CE=0.43~0.45 of the patented material , the welding performance is not ideal;

[0004] The Chinese Patent Publication No. CN1218115A discloses an invention patent for a copper-boron low-carbon and ultra-low-carbon bainite high-strength steel. High strength is obtained by precipitation and precipitation, the material structure is low carbon bainite, the tensile strength reaches 630MPa, it has high and low temperature impact toughness (CVN-80℃=124J), but the yield ratio is high (Rel / Rm=0.9), and The value of TS×EL (Strength-Elastic Product) is only 13860MPa%. When the stamping forming process is used in the subsequent process, the stamping formed parts will have a large rebound, which is difficult to meet the general cold stamping forming process;

[0005] The Chinese Patent Publication No. CN1824816A discloses an invention patent for a lengthened automobile frame steel and its manufacturing method. The tensile strength reaches 580MPa, the yield strength ratio is 0.83, TS×EL=15822~16588MPa%, and has good comprehensive properties such as strength and formability, but the addition of Nb+V+Ti reaches 0.1%, and the production cost is high

Although the above-mentioned patented technology has been improved in some aspects, it still has defects in different aspects, and it is obviously difficult to meet the comprehensive requirements of automobile structures for steel plate materials

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