The thinning rate of automotive hot stamping parts is concentrated on the influence of process parameters

Ultra-high-strength steel hot stamping parts can not only ensure safety, but also achieve lightweight, so more and more applications in automobiles. However, these auto parts have complex spatial curved surfaces, which are severely deformed during hot stamping, and there are many influencing factors such as heat, force, and phase changes. The forming process is complex, resulting in uneven distribution of stress, strain, and organization of the sheet material, and excessive sheet metal Thinning affects the structural strength of parts, and even cracking defects appear. At present, scholars have conducted research on the influence of process parameters on the sheet metal thinning rate. Studies have shown that the sheet metal temperature, blank holder force, and friction coefficient can all affect the sheet metal thinning rate. In order to reduce the thinning rate and ensure the structural strength of the parts, this paper proposes to pre-form the sheet material to change the stress and strain distribution of the hot stamping, and then complete the hot stamping. The shape and size of the preform have a greater impact on the hot stamping of ultra-high-strength steel plates, especially on the thinning rate of the plate, which in turn affects the structural strength of the parts. Therefore, it is necessary to study the hot stamping pre-forming of ultra-high-strength steel plates. Shang Xin proposed that the ultra-high-strength steel is subjected to dual hot forming under different hot pre-forming strokes, and the thickness distribution of the formed parts after forming is obtained. The results show that when the hot pre-forming stroke is 0.5H (H is the stroke), the forming The thickness distribution of the parts is the best. Liu Wen proposed that the high-strength steel should be pre-formed in the cold state and then hot stamped to form the final part, and the influence of the forming stroke on the hot stamping was studied. The results showed that the larger the pre-forming stroke, the sheet material will be hot stamped in the second step. The smaller the heat loss, the better the plasticity of the material, the smaller the equivalent strain, and the smaller the change in sheet thickness. Lu Mengmeng proposed to directly cold-stamp ultra-high-strength steel plates to form parts, and then heat them for hot stamping. The results show that the accuracy of indirect hot stamping parts is higher than that of direct cold stamping parts. Based on the above research status, it can be seen that the current research on the thinning rate of complex automotive hot stamping parts mainly focuses on the influence of process parameters on the thinning rate. The research on the pre-forming of complex automotive hot stamping parts focuses on the influence of the pre-forming stroke and the process parameters during hot stamping on the formability. There are few studies on the influence of the shape and size of the pre-formed parts on the thinning rate. Taking the wheel side cover parts as the research object, as shown in Figure 1, the wheel side cover is a structural part that needs to withstand static pressure and impact load, and its mechanical performance requirements are high. Ultra-high-strength steel can be used as a material to meet the requirements. Its mechanical performance requirements. However, the shape of the part is complex, especially the concave ball in the middle of the part, which needs to be reverse-formed during deep drawing, which easily causes the part to be excessively thinned, which affects the comprehensive performance of the part. According to the structural characteristics of the wheel side cover, firstly, the finite element method was used to simulate the cold forming and hot stamping processes of different preform shapes, and the influence of preforming on the thinning rate was analyzed. Based on the simulation results, the actual hot stamping of the wheel side cover was carried out. Experiment and obtain satisfactory experimental results. Previous post: Prospects of related technologies for powder fuel ramjets