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High-strength steel hot-formed parts are widely used as safety protection parts for automobiles due to their ultra-high strength (1500( -2000. In order to prevent the oxidation and decarburization of traditional high-strength steel sheets during the heating process of hot forming, and at the same time enhance the corrosion resistance of hot-formed parts, galvanized high-strength steel sheets have been applied. The hot forming process of galvanized high-strength steel plate is studied, the mechanism of LMIE crack generation is analyzed, and the hot-forming process route suitable for galvanized high-strength steel plate is formulated. The key process parameters in the hot stamping process of zinc-based plated sheets, namely heating temperature, holding time, effective range and effect of forming temperature, are studied. Short-term heating, pre-cooling forming, shortening the holding time of the sheet, and then reducing the temperature of the sheet to a certain extent by a specific method before forming, the results show that when the forming temperature is low (700 °C), the matrix basically has no cracks. The reduction of the forming temperature is beneficial to the elimination of liquid zinc in the coating, thereby preventing the occurrence of LMIE phenomenon. In addition, when the forming temperature is low, the matrix phase transition temperature range becomes narrow, and the rate of forming cooling is required to be higher. The new generation of zinc-based coated sheets can improve the low temperature hardenability, which is beneficial to the pre-cooling low temperature forming process, which can be regarded as the future direction.

In this study, the ZnFe coated boron steel specimens were treated by rapid heating at different heating rates from 20 °C/s to 100 °C/s. The coating morphologies and phase compositions were characterized to investigate the influence of heating rate on phase transformation of ZnFe coating. The results indicated that there was no continuous α-Fe(Zn) layer formed at coating/substrate interface during the heating-up stage when the heating rate was higher than 50 °C/s. As a result, the phase transformation of the coating was facilitated. At the heating rate of 100 °C/s, a one-layer coating structure composed of α-Fe(Zn) phase was formed within 100 s, which is significantly shortened compared to the traditional furnace heating method.