目的 以H13热冲压模具钢为研究材料，探索不形成化合物层的低温创新离子渗氮工艺，旨在提高H13钢热冲压模具的抗冲击性和抗疲劳性，延长服役寿命。方法 将H13钢试样放在LD-8CL型直流离子渗氮炉内进行离子渗氮处理，渗氮温度分别为470、490、510 ℃，保温时间为8 h。利用光学显微镜、X射线衍射仪、压痕检测法及自行设计的热疲劳实验，对渗氮后的H13钢显微组织、物相组成、渗层脆性和热疲劳性进行了测试与分析。结果 与普通离子渗氮相比，H13钢经470 ℃低温离子渗氮处理后，表层无化合物层生成；渗层脆性显著降低，在较大检测载荷下压痕周围无裂纹产生；同时，抗热疲劳性提高3倍以上。将470 ℃低温无化合物层创新离子渗氮技术应用到汽车板件热冲压模具中，使模具冲压能力由之前18 000~20 000件提升到80 000~100 000件，即服役寿命提高到5倍左右。结论 H13钢经470 ℃低温离子渗氮处理后，表面无化合物层产生，具有良好的韧性，与常规离子渗氮相比，该技术能够显著提高表面抗热疲劳性以及模具的服役寿命。

The work aims to use H13 hot stamping die steel as the research material to explore the low temperature plasma nitriding process without formation of compound layer so as to improve the impact resistance and thermal fatigue resistance and prolong the service life. Plasma nitriding treatment was conducted to H13 steel specimen in a LD-8CL D. C. plasma nitriding furnace at 470, 490 and 510 ℃ for 8 h. The microstructure, phase composition, brittleness and thermal fatigue of H13 steel after plasma nitriding were tested and analyzed by optical microscope, X-ray diffraction, indentation test and self-designed thermal fatigue test. Compared with conventional plasma nitriding, H13 steel treated by low temperature plasma nitriding at 470 ℃ had no compound layer in the surface layer. The brittleness of the layer was significantly reduced and no cracks occurred around the indentation under the larger detection load. Meanwhile, the thermal fatigue resistance increased by more than three times. The 470 ℃ low temperature non-compound layer plasma nitriding was applied to the hot stamping die of vehicle plates to increase the service life about 5 times, from 18 000~20 000 pieces to 80 000~100 000 pieces. H13 steel after low temperature non-compound layer plasma nitriding at 470 ℃ has no compound layer on the surface, but has good toughness. Compared with the conventional plasma nitriding, the technology can significantly improve the thermal fatigue resistance and service life of die.