When using medium frequency induction heating power to heat sleeve parts, how to prevent them from deforming?

The structural characteristic of sleeve parts is that the wall thickness of the hole is relatively thin. When processing thin-walled parts using medium frequency induction heating power, they are often deformed due to the influence of clamping force, cutting force and thermal deformation. The following process measures can be taken to prevent deformation.

(1) Roughing and finishing are carried out separately. In order to reduce the influence of cutting force and cutting heat, the deformation caused by roughing can be corrected in finishing.

(2) To reduce the influence of clamping force, take the following measures in the process.

① When using radial clamping, the clamping force should not be concentrated on the radial section of a certain axis of the workpiece, but should be distributed over a larger area to reduce the clamping force per unit area of the workpiece force.

② The position of the clamping force should be selected in a relatively rigid part of the part to improve the deformation of thin-walled parts under the action of the clamping force.

③Change the direction of the clamping force from radial clamping to axial clamping. A process boss or process thread with enhanced rigidity is made on the workpiece to reduce clamping deformation. During processing, a specially structured claw is used for clamping, and the convex edge is cut off at the end of processing.

(3) Reduce the influence of cutting force on deformation.

① Increase the main deflection angle and main pin angle of the tool to make the cutting edge sharp during processing and reduce the radial cutting force.

② Separate roughing and finishing machining so that the deformation caused by roughing can be corrected during finishing and use smaller cutting amounts.

③ It can be corrected when the inner and outer circular surfaces are processed at the same time, but attention should be paid to appropriately increasing the finishing allowance.

④ The heat treatment of sleeve parts using medium frequency induction heating power should be placed between rough machining and finishing machining. This arrangement can reduce the impact of heat treatment deformation. Sleeve-type parts generally undergo large deformation after heat treatment, which can be corrected during finishing, but attention should be paid to appropriately increasing the margin for finishing.

(4) Carburizing and slow cooling → Inner hole → After secondary quenching, the solution to whether the inner hole deformation is elliptical (tooth jump out of tolerance) or uniformly expanded by 0.20~0.40mm is as follows:

① If the swelling is more uniform, just use less.

② If it is an ellipse, check the tooth jump; if the gear is too heavy, it will easily lead to local gear out-of-tolerance, and the noise cannot be solved. If the requirements are strict, it will basically be a waste product (unless the gear is ground).

③The expansion of the inner hole has a lot to do with the process method used. The main reason is that the carbon layer disappears after the inner hole, and the stress state during the quenching process is completely different.

④ Since it is a ring gear, the secondary quenching can be done by stacking, and end jumping should be better than hanging. At the same time, the deformation pattern of the inner hole is generally not elliptical, it may still be swollen, but the pattern will be very strong, so just reduce the amount of turning.