Niobium-containing high-strength fine-grain 700MPa-level hot-rolled dual-phase steel and production method thereof

Abstract

The invention discloses a niobium-containing high-strength fine-grain 700MPa-level hot-rolled dual-phase steel and a production method thereof. A steel plate with a polygonal ferrite and martensite dual-phase structure is obtained by a hot rolling and sectional control cooling process. The dual-phase steel comprises the following chemical components in percentage by weight: 0.07-0.10% of C, 0.20-0.50% of Si, 1.20-1.50% of Mn, less than or equal to 0.03% of P, less than or equal to 0.03% of S, 0.08-0.11% of Nb and the balance of Fe and unavoidable impurities. The production method of the dual-phase steel comprises the following steps: preparing materials according to the chemical components of the dual-phase steel; smelting in a vacuum induction furnace, and pouring the molten steel to obtain a steel ingot; heating the steel ingot and starting rolling; controlling the rolling at two stages; after the rolling, performing sectional cooling; and finally conveying the product to a coil storehouse. The dual-phase steel disclosed by the invention has the advantages of good strength-toughness match of steel plate, high tensile strength of steel plate, low yield ratio and good stamping property.

Description

Technical field: [0001] The invention relates to a high-strength fine-grain hot-rolled dual-phase steel and a production method thereof, in particular to a niobium-containing high-strength fine-grain 700MPa hot-rolled dual-phase steel and a production method thereof. Background technique: [0002] Iron and steel materials are still the main structural materials in the 21st century. High performance and low cost are the development direction of steel materials in the future and a necessary prerequisite for sustainable economic development. With the development of modern automobiles in the direction of high safety, economical and environmental protection, and long life, higher and higher requirements are put forward for the strength, formability, and corrosion resistance of automobile sheets. Due to its high strength and high formability, hot-rolled dual-phase steel has been widely used in the manufacture of automobile reinforcement plates, wheels, chassis, bumpers, various fr...

AI Technical Summary

Problems solved by technology

When the Si content is high, it is more difficult to control the surface quality of the hot-rolled sheet, adding alloy elements such as Cr and Mo, and the cost is high; (2) a three-stage cooling process is adopted, such as: Chinese Patent Publication (Announcement) No. A kind of 600MPa grade hot-rolled dual-phase steel and its preparation method

Due to its high requirements on the cooling process, the three-stage cooling process is used, and the industrial production is limited.

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