Abstract: Because the gear and other workpieces in the high-pressure gas quenching were greatly affected by the multilayer workpiece heat storage and the wind speed decrease layer by layer, resulting in the slow cooling of the workpieces placed in the center and the bottom area of gas quenching chamber, it is difficult to meet the hardness requirements of the gear center. The fluid simulation software was used to simulate the high-pressure gas quenching process. The three-dimensional modeling of the gas quenching chamber and the workpiece stack with structured mesh division was established of automobile gears, and then simulation was carried out, based on which the structure of gas quenching chamber was optimized. The results show that after optimization, the high-pressure air flows at the inlet converge to the central area, increasing the inflow velocity of the central area by about 24% and increasing the cooling rate of this area. Subsequently, the high-pressure gas quenching chamber was renovated and verified through experiments. The results show that this method is effective and feasible.

Key words: 18CrNiMo7-6 steel gear, high-pressure gas quenching, core hardness, numerical simulation