Method for measuring volume distribution of retained austenite in transformation induced plasticity (TRIP) steel stamped part

Abstract

The invention relates to the field of performance measurement of steel stamped parts and in particular to a method for measuring the volume distribution of retained austenite in a transformation induced plasticity (TRIP) steel stamped part. The method for measuring the volume distribution of retained austenite in the TRIP steel stamped part comprises the following steps of: firstly classifying the deformations into four standard deformation modes; then deducing the law of retained austenite transformation under a complicated strain path according to the plastic deformation theory; and finally calculating the volume content of retained austenite of each point on the part after deformation according to the main and secondary strain magnitudes. The method can be used for obtaining the volume content of retained austenite only by measuring the main and secondary stresses of the stamped part; has the advantages of simplicity of implementation, accurate result and low time and economic costs; and provides a basis for improving the formability of the TRIP steel by improving the part shape and the process addendum and/or the design of draw beads, so as to take full advantage of the effect of transformation induced plasticity of the TRIP steel and increase the application range of the TRIP steel.

Description

technical field [0001] The invention relates to the field of performance measurement of steel stamping parts, in particular to a method for measuring volume distribution of retained austenite in steel stamping parts. Background technique [0002] The modern automotive industry has higher and higher requirements for lightweight, safety, exhaust emissions, cost control and fuel economy, which drives the automotive industry to adopt high-strength steel plates and some high-strength lightweight materials. The TRIP steel developed by using the phenomenon of Transformation Induced Plasticity (TRIP) in the deformation process not only has high strength, but also has good plasticity. It has begun to be applied in the foreign automobile industry and has shown broad application prospects. It has attracted extensive attention from the international steel and automobile industries. As a new type of steel plate, TRIP steel plate contains retained austenite in its microstructure at room ...

AI Technical Summary

Problems solved by technology

For stamping parts, to determine the distribution of retained austenite, the sample required for the preparation of the above method needs to cut the stamping parts into many small pieces, and perform surface polishing or corrosion, which increases additional process costs and measurement costs. For For a large and complex TRIP steel stamping, the number of measurements and the cost of measurements required to determine the volume distribution of retained austenite using the above-mentioned direct measurement method will be higher, which is often unbearable

Therefore, the direct measurement method to determine the distribution of retained austenite in the stamping process of TRIP steel is not suitable for industrial applications.

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