Cold-rolled high-strength steel with good coating quality and preparation method thereof

Abstract

The embodiment of the invention discloses cold-rolled high-strength steel with good coating quality and a preparation method thereof. The steel comprises the following chemical components in percentage by mass: 0.08-0.30% of C, less than or equal to 2% of Si, less than or equal to 4% of Mn, less than or equal to 1% of Al, less than or equal to 0.005% of B, 0-1.5% of Cr, less than or equal to 0.010% of P, less than or equal to 0.006% of S, and the balance Fe and other inevitable impurities, wherein the ratio of the mass fraction of the element Si to that of the element Mn is less than or equal to 0.5, and the ratio of the mass fraction of the B element to that of the element Mn is less than or equal to 0.005. The method comprises the steps: carrying out smelting, continuous casting, heating before rolling, rough rolling, finish rolling, cooling after rolling, coiling, acid pickling, cold rolling, annealing, cooling after annealing and surface coating on chemical components of the steel to obtain the cold-rolled high-strength steel. According to the embodiment of the invention, Si / Mn is controlled to be less than or equal to 0.5, B / Mn is controlled to be less than or equal to 0.005, and B is controlled to be less than or equal to 0.005%, so that the prepared cold-rolled high-strength steel has a good coating characteristic.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of cold-rolled high-strength steel preparation, in particular to a cold-rolled high-strength steel with good coating quality and a preparation method thereof. Background technique [0002] Cold-rolled high-strength steel is an important supporting material for automobile weight reduction. With the acceleration of the lightweight process of automobile bodies, more and more cold-rolled high-strength steels are used in body manufacturing, such as dual-phase steels, TRIP steels, multi-phase steels, and martensitic steels. The structures of these cold-rolled high-strength steels are mostly a combination of martensite, ferrite and a small amount of austenite. The common feature of these cold-rolled high-strength steels is that they are strengthened through phase transformation, and in order to achieve different phase transformation processes, it is necessary to add a variety of alloying ...

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Problems solved by technology

This kind of oxide film is extremely unfavorable to the coating process of high-strength steel in automobile production, and it is easy to cause difficulty in surface phosphating during coating, and it is impossible to form a complete phosphating film, resulting in poor quality of electrophoretic film

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