Among the main factors affecting the gear heat treatment deformation, the only thing that can be improved by the heat treatment department is the heat treatment itself or the material. In order to improve the cold and hot processing conditions of gears, the heat treatment plant of Hangzhou gear group company is equipped with isothermal annealing production line and two advanced multi-purpose box furnace production lines with automatic control of carbon potential. At the same time, the company also began to change its thinking and gradually began to adopt controlled hardenability strip steel in recent years. Therefore, the deformation test research is based on the improvement of pre heat treatment, the improvement of gear carburizing process and the use of controlled hardenability strip steel.
According to the above ideas, the contents and objectives of the experimental research work are as follows:
- Study on Carburizing deformation of key gear blank of heavy truck gearbox after isothermal annealing;
- The influence of carburizing and quenching equipment and process mode on the deformation of carburized gear;
- In view of the conventional performance inspection, hardenability band inspection and deformation comparative analysis of 20crmntiha2, 20crmntiha3 and 20crmntiha4 of 20crmntiha series, which replace the ordinary 20CrMnTi carburized steel and are developed by Daye Steel Plant, the influence of material hardenability on gear deformation is mainly studied.