Device and method for testing transient hot forming limit of metal sheet

Abstract

The invention provides a device and method for testing the transient hot forming limit of a metal sheet. The test device comprises: a two-way stretching experimental device, a computer control system,an optical strain measurement system, an infrared thermometer, an electromagnetic induction heating device, a cooling device, wherein the optical strain measurement system photographs the surface deformation of a cross-shaped sample by a CCD camera; the electromagnetic induction heating device heats and maintains the temperature of the central portion of the cross-shaped sample through a mosquito-coil induction coil; and the cooling device cools the high-temperature cross-shaped sample by a high-pressure air nozzle. The device can cool the high-temperature cross-shaped sample during a stretching process at a specified cooling rate so as to accurately obtain the transient ultimate strain of the material and establish a transient hot forming limit diagram, is consistent with the continuoustemperature change characteristic of an actual hot stamping metal sheet, can achieve reliable sheet formability prediction, guides process optimization, and improves production efficiency and productquality.

Description

technical field [0001] The invention relates to the technical field of advanced manufacturing technology of sheet metal hot stamping, in particular to a test device and method for testing the transient hot forming limit of sheet metal. Background technique [0002] The plastic deformation ability of metal materials at high temperature will be significantly improved. Based on this feature, sheet metal hot stamping technology has been widely researched and applied in the field of automobile manufacturing. Through the hot stamping of high-strength lightweight metal sheets, the manufacture of various body structural parts, such as B-pillars, front and rear bumpers, and side beams, can be realized. The application of high-strength lightweight metal sheets can realize the lightweight of the vehicle body while ensuring the safety of the vehicle collision. [0003] Hot stamping is a high-temperature deformation process of sheet metal, and the final forming quality of the sheet wil...

AI Technical Summary

Problems solved by technology

However, this method cannot accurately control the cooling rate of the sample; on the other hand, because the top of the punch comes into contact with the sample first, the temperature at the center of the sample is lower than that at the edge.

However, the deformation resistance at the higher temperature of the material is smaller, so the sample is easily broken at the edge, and the ultimate strain obtained in this way is inaccurate

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