280 Mpa grade cold-rolled strip for automobile structure and manufacturing method thereof

Abstract

The invention relates to a 280 Mpa grade cold-rolled strip for an automobile structure. The 280 Mpa grade cold-rolled strip is composed of the following components in percent by weight: 0.09-0.13% ofC, less than or equal to 0.05% of Si, 0.8-1.0% of Mn, 0.02-0.03% of P, less than or equal to 0.015% of S, 0.025-0.05% of Als and the balance Fe and inevitable impurities. A manufacturing method of the280 Mpa grade cold-rolled strip for the automobile structure comprises a steelmaking step, a hot rolling step, an acid continuous rolling step and a continuous annealing step. Any microalloy elementsare not added into the cold-rolled strip and C and Mn elements are reduced to the greatest extent to reduce the carbon equivalent so as to guarantee the welding quality. By adding a small amount of strong solution strengthening element P, mechanical property indexes: the yield strength is greater than or equal to 280 Mpa, the tensile strength is greater than or equal to 440 MPa and the ductilityis greater than or equal to 30%, are achieved finally by means of process control such as steelmaking, hot rolling, acid continuous rolling and continuous annealing, so that the processing and using demand of an automobile structural part is met.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a 280Mpa grade cold-rolled steel strip for automobile structures and a manufacturing method thereof. Background technique [0002] With the continuous improvement of automobile production and sales, the demand for automotive steel is also increasing. Although the proportion of high-strength steel required for lightweight automobiles continues to increase, cold-rolled steel strips for automotive structures with a yield strength of about 300Mpa still occupy the mainstream. Including high-strength IF steel, low-alloy structural steel, dual-phase steel, etc. However, with the continuous compression of automobile costs, how to reduce the cost of steel strips under the premise of ensuring the same quality has become one of the research topics. [0003] CN106191663A discloses an iron-zinc coated steel sheet with a yield strength of 280MPa and a production method. Its ch...

AI Technical Summary

Problems solved by technology

Compared with the present invention, no strong solid solution strengthening element P is added, and the C content is relatively high, resulting in a high carbon equivalent, which has an impact on the welding performance of automotive structural parts

Images