Method for predicting residue austenite content in Q&P steel after single-direction stretching at different strain rates

Abstract

The invention discloses a method for predicting the residue austenite content in Q&P steel after single-direction stretching at different strain rates. According to the method, firstly, an expression of the instant residue austenite content and the strain rate and the equivalent plastic strain after the Q&P steel deformation is firstly deduced; then, the initial austenite content of plates is measured; the plates are stretched to the preset strain at different strain rates, unloading is carried out, in addition, the residue austenite content is measured, the fitting is carried out on the basis of test data to obtain the expression of the residue austenite content of the plates after the single-direction stretching at different strain rates along with the equivalent plastic strain; an inquiry chart is drawn on the basis of the expression; finally, the residue austenite content in the Q&P steel after the single-direction stretching at different strain rates can be precisely predicted through measuring the equivalent plastic strain after the deformation by combining the strain rate in the deformation process. The method has the advantages that simplicity and accuracy are realized, the cost is low, and in addition, the implementation is easy. According to the method, the residue austenite content of the plates after the punching can be accurately predicted, and the basis can be provided for the punching process improvement, so the Q&P steel popularization is accelerated.

Description

technical field [0001] The invention relates to the technical field of metal material forming, in particular to a method for predicting the residual austenite content of Q&P steel after single drawing at different strain rates. Background technique [0002] With the continuous improvement of the automotive industry's requirements for body weight reduction and passive safety, the use of high-strength lightweight materials has become an effective means of weight reduction. Due to its excellent mechanical properties, the application proportion of advanced high-strength steel in the car body is increasing year by year. At present, it has been widely used in formed car body structural parts and reinforcements, such as A / B / C pillars, door anti-collision beams, beams, longitudinal Liang et al. [0003] In 2003, Speer et al. in the United States proposed a new process for preparing high-strength automotive steel, the quenching and partitioning process. This process can be used to ...

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Problems solved by technology

However, the strain rate of sheet metal deformation in the actual stamping process is relatively large, which has exceeded the quasi-static strain rate range of traditional tests, and the strain rates of different types of parts in the stamping process may be different. Therefore, the traditional met

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