Induction heating pre shrinkage inner hole processing technology for motorcycle sprocket:
After carburizing the internal wheel with spline holes, high-frequency induction quenching is carried out on the enlarged part of the internal hole to pre drill the gear, and then heat quenching is carried out to meet the technical requirements of the spline hole ruler. This method is abbreviated as pre fine pore method Example motorcycle sprocket, made of 2CMnTi steel, with a carburized layer size of 0.8-1.2mm (1) The distortion of motorcycle sprockets is caused by conventional carburizing and quenching, resulting in conical distortion of the keyway holes inside the motorcycle sprockets, and the size of the inner holes exceeds the tolerance, making assembly difficult (2) Improvement measures and control effect of motorcycle sprocket distortion are achieved by using induction heating to pre shrink the inner hole. After carburizing the motorcycle sprocket, high-frequency induction quenching is first performed on the key hole to achieve shrinkage, and then heating quenching is carried out. A one-to-one quenching fixture is used during quenching, as shown in Figure 7-37, to reduce thermal stress and prevent shrinkage distortion. The large end, which has already shrunk, swelled after quenching, and there was no taper hole distortion in the keyway hole of the motorcycle sprocket The size of the sensor used for pre shrinking the inner hole of the motorcycle sprocket is 48mm x 10mm. When using the sensor, its top should be 1.5~2.5mm lower than the inner hole. When the temperature of the inner hole reaches 840-870, quenching and cooling can be carried out. The result shows that the large end aperture is between 60-0.01mm, and the small end aperture is between 60-0.2mm. The size of the keyway inner hole remains basically unchanged or reduced by 0.02mm, and the two K meet the technical requirements of the product When using the induction heating method to pre shrink the inner hole, the following precautions should be taken:1) If the sensor is higher than the large end hole, the hole will severely shrink by 0.12~0.14mm. At the same time, it is advisable for the height of the sensor to be 1/3 of the length of the inner hole. At this time, heating has little effect on the distortion of Xiaorui
2) When heating and quenching motorcycle sprockets, the pre cooling time should not be too long, otherwise oil cooling can easily increase thermal stress and make the small end aperture smaller