Today's high-strength steel and ultra-high-strength steel achieve the light weight of the vehicle and improve the collision strength and safety performance of the vehicle, thus becoming an important development direction of the steel for the vehicle. However, with the improvement of the strength of the sheet, the conventional cold stamping process is prone to cracking during the forming process, and cannot meet the processing requirements of the high-strength steel sheet. In the case where the molding conditions cannot be satisfied, the hot stamping forming technology of ultra high-strength steel sheets has been gradually studied internationally. This technology is a new process that combines forming, heat transfer and tissue phase transformation. It mainly uses the high-temperature austenite state, the plasticity of the sheet increases, and the yield strength is reduced. However, thermoforming requires in-depth study of process conditions, metal phase transitions, and CAE analysis techniques. This technology is monopolized by foreign manufacturers and domestic development is slow.
In the past, in the production of deep-drawn or over-punched workpieces, we all think that pressure-resistant (EP) lubricants are the best choice for protecting molds. Sulfur and chlorine EP additives have been mixed into pure oils to improve mold life for a long time. However, with the emergence of new metals - high-strength steel, strict environmental requirements, the value of EP oil-based lubricants has been reduced, and even lost market.