①Forming problems of high-strength steel
High-strength steel has poor plasticity, is prone to cracking when deformed, has high deformation resistance, large rebound after forming, and poor dimensional accuracy of parts. Through the laser welding of high-strength steel plates, the parts with larger deformation are borne by mild steel or high-strength steel with better formability, while the parts with smaller deformation or need to bear larger loads are made of high-strength steel with a higher strength level. steel. In addition, new forming technologies have been developed, such as hydroforming, warm forming and hot stamping.
②Welding problems of high-strength steel
Due to different production process technologies, the amount of alloying elements added must also be different. When the cooling rate is low, more alloying elements must be added, but this will also cause deterioration in welding performance. For high-strength steel coated products, the coating composition, its organizational structure and coating thickness all affect its welding performance.
③Painting issues of high-strength steel
The surface enrichment and oxidation of alloy elements in high-strength steel affect its coating performance. The chemical composition of the coating and the surface morphology of the coating also affect the coating performance of the material. By controlling the atmosphere in the furnace during the heat treatment process, the surface enrichment and oxidation of alloy elements of high-strength steel can be controlled, thereby improving the coating performance of high-strength steel. The pickling method is used to clean the alloy elements diffused on the surface of the coating, and then a very thin layer of nickel is electroplated to improve its coating performance.
Conclusion
High-strength steel automobile sheets will be the mainstream of automobile sheet development in the future. The extensive use of high-strength steel is an important way to solve automobile weight reduction, energy saving, safety, and environmental protection. Compared with aluminum alloys and magnesium alloys, it has strong competitiveness. At present, it is necessary to further study the micro-mechanism of TRIP steel to increase its ductility, actively explore the commercial production of cold-rolled and hot-rolled TWIP steel, and strengthen the research on the bake hardening characteristics and micro-mechanism of DP steel and TRIP steel. In addition, the forming must be strengthened. Development of numerical simulation technology for processes, etc.
