980MPa-grade high-ductility and low-density austenitic steel for automobiles and preparation method of austenitic steel

Abstract

The invention discloses 980MPa-grade high-ductility and low-density austenitic steel for automobiles. The austenitic steel is prepared from the following chemical components in percentage by mass: 0.5%-1.0% of C, 0.2%-0.5% of Si, 12%-16% of Mn, 5%-8% of Alt, 0.1%-0.3% of Ti, 0.02%-0.04% of Ce, 0.01% or less of P, 0.01% or less of S, 0.004% or less of N and the balance of Fe and trace elements. Thepreparation method of the austenitic steel for the automobiles comprises the steps of molten iron continuous casting, rough rolling, finish rolling, cooling, coiling, cold rolling, continuous annealing and leveling. According to the method, based on a conventional air jet cooling annealing production method, a reasonable alloy component system and a reasonable process method matched with the alloy component system are designed, so that the low-density austenitic steel has good elongation and work hardening capability.

Description

technical field [0001] The invention relates to a 980MPa-grade high-ductility low-density austenitic steel for automobiles and a preparation method thereof, belonging to the technical field of high-strength light-weight steel. Background technique [0002] Reducing fuel consumption and improving body safety are the development trends of the automobile industry. Reducing the weight of a car is an effective way to reduce fuel consumption, which requires the use of thinner steel plates. However, the thinning of steel will inevitably lead to the reduction of the safety performance of the automobile body. In order to alleviate this contradiction, it is necessary to use high-ductility and high-strength steel plates. However, the weight reduction achieved by high-ductility high-strength steel sheets has reached the limit, and further development of lightweight steel is required to achieve weight reduction. [0003] Compared with the competing lightweight material Al, low-density ...

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Problems solved by technology

[0006] The present invention aims to provide a 980MPa grade high-ductility low-density austenitic steel for automobiles and its preparation method, which mainly solves the problem of brittle k-precipitates (Fe, Mn) in low-density steel due to the large amount of Al contained 3 AlC, makes the ductility very poor, and causes technical problems of edge cracking during rolling (hot rolling, cold rolling)

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