Method for acquiring metal temperature forming limit diagram (TFLD) and testing device therefor

Abstract

The invention discloses a method for acquiring a metal temperature forming limit diagram (TFLD). The method is characterized by comprising acquiring a TFLD of a high-strength steel plate thermal-forming process, and acquiring a TFLD of a lightweight alloy warm-forming process. The invention also discloses a test device of a TFLD. The test device is characterized by comprising a hydraulic tester, a mold, a mold heating furnace, an automatic feeding mechanism, a plate heating furnace, a plate fast-cooling device, a heating control system and a strain measurement analysis device. The method and the test device guarantee mold heating uniformity, do not change a plate forming temperature, satisfy temperature forming requirements, acquire the TFLD comprising the all-range isothermal or non-isothermal forming limit diagram in a test temperature range, have the advantages of simple operation, high automation degree and high work efficiency, and satisfy practical temperature forming process requirements.

Description

technical field [0001] The invention relates to the technical field of sheet metal forming, in particular to a method for obtaining a limit surface diagram of metal high-temperature warm forming and a testing device thereof. Background technique [0002] In recent years, due to the aggravation of energy and environmental problems, the problem faced by automobile design and manufacture is how to realize the lightweight of automobiles on the premise of ensuring the passive safety of automobiles, so as to improve automobile fuel economy and reduce exhaust emissions. Optimizing the structural design of automobiles, using new materials and corresponding advanced manufacturing technologies are the main methods to solve the above problems. High-strength steel plate hot stamping forming technology is a new type of advanced manufacturing technology specially used for forming high-strength steel plate. It can produce thinner but higher strength parts. The tensile strength can reach mo...

AI Technical Summary

Problems solved by technology

However, the thermoforming process is a non-isothermal process. During the forming process, the temperature of the sheet metal changes continuously according to the contact conditions and deformation conditions. The formability of the sheet metal in this process is mainly affected by factors such as temperature and forming rate. It is inaccurate to evaluate the formability of sheet metal in the hot forming process by using the forming limit curve at a single temperature and forming rate

[0006] Considering the principle of hot forming and the influence of forming limit on temperature and forming rate, the patents with application numbers 201110082554.7 and 201210238542.3 both mentioned the forming limit test device and how to obtain the forming limit diagram, but the existing devices and testing methods for the high temperature forming limit of sheet metal It is difficult to accurately obtain the TFLD-Temperature Forming Limit Diagram (TFLD-Temperature Forming Limit Diagram) of high-strength steel plates under the warm forming process. Lack of necessary and effective sheet rapid cooling device to quickly cool the sheet to the test temperature, resulting in structural transformation of the sheet

In addition, the method proposed in the patent application number 201220130204.3 is to use induction coils to heat the sheet metal. Although the air nozzle is used to cool the sheet metal before forming, but at this time the sheet material is in contact with the preheated mold, and the mold will indirectly A drop in temperature occurs, making it difficult to keep the mold temperature constant, making the measured forming limit inaccurate

In addition, when determining the high-temperature hot forming limit of steel plates without anti-oxidation coating, the prior art lacks necessary anti-oxidation devices, resulting in invisible grids after forming

Moreover, there is no effective method for evaluating the formability of parts in the isothermal or non-isothermal forming process of warm and hot forming in the prior art.

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