High-strength cold-formed hot continuous rolled steel plate and method of preparing the same

Abstract

The invention relates to a high-strength cold-forming hot-continuous-rolling steel plate and the manufacture method thereof, wherein, the chemical composition of the steel plate is as follows: 0.05wt percent to 0.10wt percent of C, 0.10wt percent to 0.50wt percent of Si, 1.0wt percent to 2.0wt percent of Mn, less than or equal to 0.025wt percent of P, less than or equal to 0.010wt percent of S, 0.03wt percent to 0.08wt percent of Nb, 0.05wt percent to 0.15wt percent of Ti, 0.10wt percent to 0.50wt percent of Mo, 0.0010wt percent to 0.0050wt percent of Ca, 0.01wt percent to 0.05wt percent of Al and the rest, Fe and other inevitable impurities; the technical process of the steel plate includes hot metal deep desulfurization to converter top and bottom blowing to secondary refining to continuous casting (machine cleaning) to hot charging hot feeding soaking pit to plate blank reheating to controlled rolling to controlled cooling to coiling to finishing. With the yield strength reaching 700 MPa, the steel plate has excellent mechanical property and processing properties such as welding and roll forming; meanwhile, because less alloying element is added during the manufacture process of the steel plate, the invention has low production cost and convenient operation during big production without adopting heat treatment processes such as tempering and quenching and tempering. The invention can be used in fields such as engineering machinery and structural parts and container for special vehicle and strongbox, etc.

Description

technical field [0001] The invention relates to the field of low-alloy steel manufacturing, in particular to a high-strength cold-formed hot-rolled steel plate and a production method thereof. Background technique [0002] In today's increasingly tense energy supply, enhancing the strength of materials and reducing the weight of components represents the development direction of structural steel. The application of high-strength steel can significantly reduce the weight of the components and the self-weight of the equipment, thereby reducing the fuel consumption of the equipment and improving the working efficiency of the equipment. Therefore, there is an urgent need for a steel with high strength and excellent comprehensive mechanical properties in the fields of mobile equipment such as containers, automobiles and railway vehicles. [0003] After searching, it is found that the existing high-strength steel types have certain defects. For example, the patent (CN1651589A) "...

AI Technical Summary

Problems solved by technology

Its shortcomings are: in order to improve the strength of steel, high content of Cu and Ni are added in the composition design, and it also contains Mo, Cr and other precious alloying elements, which not only increases the cost of steel, but also adds a large amount of alloying elements. The carbon equivalent and crack sensitivity coefficient of the steel are increased, which has an adverse effect on its welding performance, and although a large amount of precious alloy elements are added to this steel, its yield strength can still only reach ≥500MPa, and the strength cannot meet the demand

[0005] Another example is the patent of the same family applied by Nippon Steel in China (CN1639371A) "Weather-resistant high-strength steel plate with excellent bending workability and its manufacturing method". Up to 2.0%, Ti content up to 0.2%, higher alloy elements not only can not significantly improve the strength of steel, but also increase the production process, the production operation is complicated

[0006] In addition, during the rolling process, the MnS inclusions in the steel are easily deformed and elongated along the rolling direction, thereby affecting the isotropy of the steel plate. The composition design of the above patents does not consider adding Ca or rare earth to denature the sulfide. deal with