Preparation method of high-carbon hot-continuous-rolling acid-pickling steel strips for hot forming

Abstract

The invention relates to a preparation method of high-carbon hot-continuous-rolling acid-pickling steel strips for hot forming, belongs to the technical field of preparation of acid-pickling steel strips, and aims at solving the technical problem of providing a low-cost preparation method of high-carbon hot-continuous-rolling acid-pickling steel strips for hot forming. According to the method, C and Mn serve as main elements, and the C content is increased; on the condition that alloy elements such as Nb, Ti, V, B, Mo, La and Cr are not added, on the premise of ensuring steel purity and chemical component uniformity of a cast blank by controlling the smelting procedure, and by means of reasonable rolling control and cooling control technological processes, hot-rolled steel plates which are moderate in strength and high in elongation rate are obtained, the hot-rolled steel plates are subjected to trimming, blanking and heating and then subjected to hot forming and hot treatment, and parts which are moderate in strength and high in ductility and toughness are obtained finally. The steel strips are widely applied to automotive structural parts and can replace part of hot-rolled and cold-rolled continuous annealing steel plates and steel strips which are high in alloy content and product cost and are used for high-strength automobile structures.

Description

technical field [0001] The invention relates to a method for preparing a high-carbon hot continuous rolling pickled steel strip for thermoforming, and belongs to the technical field of pickled steel strip preparation. Background technique [0002] The hot-rolled pickled plate is made of high-quality hot-rolled thin plate as raw material. The oxide layer is removed, trimmed and finished by the pickling unit. The main processes include uncoiling of hot-rolled raw materials → laser welding → scale breaking by the stretching and leveling unit → pickling → rinsing → On-line leveling→edge trimming→on-line oiling→baling→packing and storage, the surface quality and use requirements (mainly cold-rolled forming or stamping performance) are intermediate products between hot-rolled sheets and cold-rolled sheets, which are partly hot-rolled An ideal substitute for rolled and cold-rolled plates. Hot-rolled pickled plate is an emerging product in the plate market. Its market development d...

AI Technical Summary

Problems solved by technology

However, this manufacturing method needs to add Ti and B alloy elements to achieve the purpose of improving the material strength. The final yield strength reaches more than 1000MPa, the tensile strength exceeds 1300MPa, and the elongation reaches more than 5%. It is an ultra-high-strength hot-formed steel, although The strength is high, but the elongation is low, usually below 10%. The purpose of expanding the rolling process window can be achieved after adding Cr alloy elements, but this will increase the cost of material design

[0006] There are relatively few studies on low-cost, medium-to-high-strength hot-formed steel. At present, the commonly used medium-strength steel for automotive structural parts is QSTE420 or QSTE500. These grades of steel are mostly hot-rolled steel for cold deformation, and their tensile strength is 400. ~600MPa, but alloy elements such as Ti and Nb are still added to the composition, and the cost is high

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