Abstract: Carburizing process of 20CrMoH steel was simulated by low pressure carburizing software, and the test was carried out on WZSTQ vacuum carburizing furnace according to the simulated output. The temperature was kept at 960 ℃, and the pressure was maintained under the carburizing pressure of 800 Pa for 25 s. The process was optimized by comparing the depth of effective carburizing hardened layer. The results show that the optimum carburizing time is 120 min. After process optimization, the deviation between the depth of effective hardened layer measured by the test and predicted by the software is within +0.23 mm, which meets the design requirements. The effective hardened layer depth predicted by the software is closer to the measured depth of the gear product, with a minimum deviation of +0.10 mm. Through the carburizing test at 930 ℃ and comparing the surface carbon content, it is proved that when the surface carbon content is 0.75% predicted by the software, it is basically consistent with the actual measured value, and the maximum deviation is -0.02%.

Key words: vacuum low-pressure carburizing software, 20CrMoH steel, effective hardened layer depth, surface carbon content