800MPa-level hot-rolled high strength chambering steel and production method thereof

Abstract

The invention discloses 800MPa-level hot-rolled high strength bainite chambering steel and a production method thereof. The 800MPa-level hot-rolled high strength bainite chambering steel consists of the following chemical components in percentage by mass: greater than or equal to 4 percent and less than or equal to 0.08 percent of C, greater than or equal to 0.5 percent and less than or equal to 0.8 percent of Si, greater than or equal to 0.5 percent and less than or equal to 1.6 percent of Mn, less than or equal to 0.005 percent of P, less than or equal to 0.004 percent of S, less than or equal to 0.004 percent of N, greater than or equal to 0.15 percent and less than or equal to 0.18 percent of Ti, greater than or equal to 0.15 percent and less than or equal to 0.25 percent of Cr, greater than or equal to 0.03 percent and less than or equal to 0.05 percent of Nb, and the balance of Fe and inevitable impurity elements. The high strength bainite chambering steel with yield strength greater than or equal to 680 MPa, tensile strength greater than or equal to 800 MPa and ductility greater than or equal to 17 percent is obtained by processes of smelting, refining, slab continuous casting, slab heating, hot rolling, three-section type laminar cooling and rolling; a steel plate with the thickness of 2.8 to 6 mm has the chambering rate over 85 percent.

Description

technical field [0001] The invention relates to a high-strength reaming steel and a manufacturing method thereof, in particular to an 800MPa hot-rolled high-strength reaming steel and a production method thereof. Background technique [0002] At present, the development trend of automotive steel is towards high strength, which is mainly measured by yield strength and tensile strength; however, for high-strength steel with high flange flanging performance requirements, higher requirements are further put forward for the hole expansion performance of steel plates. Hot-rolled reaming steel has the advantages of high strength, low yield ratio, high initial work hardening rate, and good combination of strength and toughness. It meets the development theme of automotive materials such as lightweight, high performance, safety, environmental protection, and energy saving. has been more widely used. [0003] The publication number is CN105154769A, and the application date is Septemb...

AI Technical Summary

Problems solved by technology

The patented composition design adds more expensive Mo alloy elements, and the cost of the alloy is high; at the same time, a one-step rapid cooling method is adopted after the final rolling. It is difficult to control the recrystallization of austenite in industrial production, and the cooling rate cannot be avoided. Inhomogeneous ferrite grains are formed by the fluctuation of the ferrite, which causes fluctuations in product performance; and the patent CN105154769A has the problem of high yield ratio in terms of mechanical properties. High yield ratio is likely to cause strong resilience of the steel plate, which is not conducive to the expansion rate Raising and forming of parts

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