Testing system and method of plate high temperature forming limit diagram

Abstract

The invention discloses a testing system of a plate high temperature forming limit diagram. The testing system comprises a biaxial drawing device, a material heat / force simulation testing device and a measurement analysis device, wherein the biaxial drawing device is used for carrying out drawing deformation on a sample after the sample is heated by the material heat / force simulation testing device; the measurement analysis device is used for obtaining sample deformation data and analyzing and calculating the sample transformation data so as to obtain the plate forming limit diagram. According to the testing method of the plate high temperature forming limit diagram, by designing the biaxial drawing device and corresponding samples at different strain states, the temperature and the strain velocity of a sample transformation area can be controlled accurately by using the material heat / force simulation testing device; and moreover the deformation area is free from friction during the drawing process; the operation is simple; the forming limit diagrams under different temperatures and strain velocities of a plate can be obtained; and important references are provided for process design and mold design in the plate tepidity forming technology.

Description

technical field [0001] The invention relates to the technical field of sheet metal forming, in particular to a testing system and method for a high-temperature forming limit diagram of a sheet. Background technique [0002] With the increasingly serious energy crisis, environmental problems and people's continuous improvement of automobile safety performance requirements, energy saving, environmental protection and safety have become the themes of the development of the automobile industry. The hot forming technology of high-strength steel plate is one of the advanced technologies to realize the light weight of the car body and improve the safety of the car body. Through the thinning of the body parts and the reasonable matching of high strength, the weight of the car body can be effectively reduced, the fuel consumption can be reduced, and the safety of the car body can be improved at the same time. sex. The hot stamping forming technology of high-strength steel overcomes ...

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Problems solved by technology

[0004] Due to the coupling effect of multiple factors such as complex temperature field, stress field, and structural transformation in the hot stamping forming process, it is difficult to accurately obtain the forming limit diagram of the plate at high temperature by the existing forming limit diagram test method, Dahan, Turetta and patent CN201110082554.7 etc. proposed that the test methods for obtaining the forming limit diagram of the plate at high temperature are all based on the Nakajima test method, and its disadvantages are:

[0005] (1) The temperature in the deformation area of ​​the sheet metal is difficult to keep stable

During stamping deformation, different positions of the punch come into contact with the sample successively, causing the deformation temperature of the plate to drop and be uneven;

[0006] (2) It is difficult for the punch and die to maintain sufficient rigidity at high temperature, and the requirements for the thermodynamic properties of the punch and die materials are high;

[0007] (3) It is difficult to accurately control the strain rate;

[0008] (4) It is difficult to eliminate the influence of thermal friction;

[0009] (5) The initial stage of the stamping deformation of the Nakajima test method is a bidirectional strain state, causing the lowest point on the FLC to move to the right

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