Abstract: Aiming at the problem that the round cover plate made of 20Cr2Ni4A steel inner ring of hydraulic torque converter after carburizing and quenching was warped too much to meet the machining requirements, the finite element method was used to simulate the effect of furnace charging mode and adding machining allowance at the upper and lower ends of the round cover plate on stress field and deformation field during the carburizing and quenching process of the inner ring, and the experimental verification was carried out. The results show that the charging method and increasing the machining allowance have a great influence on the stress field and deformation field during the carburizing and quenching process of the inner ring. The maximum deformation amount in the order from large to small after quenching with 4 furnace charging methods is long axis vertical placement, short axis vertical placement, horizontal placement and hanging placement. Using the hanging placement can effectively reduce the warpage deformation of the plane at thin wall of 215 mm to 0.29 mm, and the warpage of the horizontal furnace can be controlled to 0.21 mm. When the machining allowance at the top of the round cover plate is increased to 11 mm, the warpage can be controlled to 0.19 mm. In terms of overall production efficiency and cost, it is advisable to use horizontal placement for production.

Key words: simulation calculation, inner ring, carburizing, stress field, quenching deformation