中文摘要：

通过对比通有保护气、无保护气、仿工业化热冲压的热冲压件的性能，研究了热冲压过程中冷速对硼钢22MnB5组织性能的影响规律。结果表明，在三种工艺条件下实验件的冷却速度均大于马氏转变的临界冷却速度，组织均为板条状马氏体，抗拉强度在1500MPa以上。冲压模具的温度升高，板料表面存在氧化皮，都会使板料的冷却速度减小，马氏体片层变粗，性能下降。通过降低模具温度，增加板料加热时的起保护，可使得板料冷速增加，马氏体组织细小，获得强度为1600MPa以上，强塑积接近20，000MPa·％的热冲压硼钢件。

英文摘要：

The effect of cooling rate during punching process on the microstructure and mechanical property of the 22MnB steel was investigated by three different processing conditions i.e. the processes with and without argon protection as well as a simulated industrial process. The results show that the cooling rates of all the hot punched parts with the three different processing conditions are higher than the critical cooling rate of 22MnB5 steel, thus the hot punched steels with a microstructure of lath mar- tensite exhibit tensile stresses higher than 1500 MPa. When the temperature of hot punch tools is higher, an oxide scale appeared on the punched workpiece surface, thereby, the cooling rate and the mechanical property of the steel become lower, and the martensitic plate becomes thicker. The hot punched part with tensile strength about 1600 MPa and strength multiplied ductility c.a. 20, 000 MPa % was available by heating with argon protection while reducing the initial temperature of punch tools to ambient tempera- ture. This is because the cooling rate of the punched part was high and thereby the martensite plates of the steel became fine for the process with protective gas.