Hot rolling steel plate with characteristic of multiple grades in one steel, and manufacturing method thereof

Abstract

The invention belongs to the technical field of metallurgy, and specifically relates to a hot rolling steel plate with a characteristic of multiple grades in one steel, and a manufacturing method thereof. The chemical components of the hot rolling steel plate comprise, by weight, 0.06-0.08% of C, 0.15-0.35% of Si, 1.20-1.50% of Mn, 0.01-0.02% of Nb, 0.01-0.02% of Ti, and the balance of Fe and impurities, wherein the tensile strength covers 520-715 MPa, the yield strength covers 385-498 MPa, the yield ratio covers 0.56-0.90, the elongation covers 23-36%, the work hardening index n value is 0.15-0.21, and the metallurgical structure is a ferrite matrix and martensite, a ferrite matrix and bainite, or a ferrite matrix and martensite and bainite. The preparation method comprises that: a hot-rolled steel plate sequentially passes through a laminar flow cooling section and an air cooling section, and then is cooled through an ultra-fast cooling section to achieve a temperature of 600-50 DEG C to coil, wherein the cooling rate at the ultra-fast cooling section is at least 80 DEG C / s. According to the present invention, the steel billet with the one component can be used for producing plural tissue types and proportions of steel plates with different strength grades, and rolling control and cooling control are adopted to achieve steel plate structure regulation so as to achieve the multiple grades in the one steel through the simple, inexpensive and low-cost component system.

Description

technical field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a one-steel multi-stage hot-rolled steel plate and a manufacturing method thereof. Background technique

[0002] With the development of automobiles in the direction of energy saving, consumption reduction, and environmental protection, steel for automobiles is facing severe challenges. Steel grades with simple design components, low cost, and meeting the performance requirements of various parts of automobiles have become the most important steel products for the automobile industry. urgent demands of the industry. In order to obtain a lightweight steel plate with good strength and toughness matching, hot rolling + heat treatment process is often used at present, or complex composition design is used to obtain high strength and good forming of ferrite matrix + hard phase through controlled rolling and controlled cooling However, the steel plates for automotive st...

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