Judging the deformation of bearing heat treatment

Use reasonable cooling methods:

The effect of cooling process on metal deformation after quenching is also an important cause of deformation. Hot oil quenching deformation is smaller than cold oil quenching, generally controlled at 100±20℃. The cooling capacity of the oil is also critical to deformation. Both the stirring mode and the speed of quenching affect the deformation. The faster the cooling speed of metal heat treatment is, the more uneven the cooling is, the greater the stress is, and the larger the variable bearing shape of the die is. Precooling can be used as far as possible under the premise of ensuring the mold hardness requirements; Stepwise cooling and quenching can significantly reduce the thermal stress and microstructure stress during metal quenching, which is an effective method to reduce the deformation of some workpiece with complex shape. Isothermal quenching can significantly reduce the deformation of some particularly complex or high precision workpiece.

Use appropriate media:

Under the premise of ensuring the same hardness requirements, try to use the oil medium, the experiment and practice proved that, under the premise of no difference in other conditions, the cooling rate of the oil medium is slow, and the cooling rate of the water-based medium is relatively fast. Moreover, compared with oily media, the change of water temperature has a greater impact on the cooling characteristics of water-based media. Under the same heat treatment conditions, the deformation of oily media after quenching is relatively small compared with that of water-based media bearings.

Part structure should be reasonable:

In the cooling process of metal after heat treatment, the thin part always cools faster and the thick part cools slower. In the case of meeting the actual production needs, should minimize the thickness of the workpiece, parts cross section strive to uniform, in order to reduce the transition zone due to stress concentration distortion and cracking tendency; The workpiece should keep the symmetry of structure and material composition and organization as far as possible to reduce the distortion caused by uneven cooling; The workpiece should try to avoid sharp edges and corners, grooves, etc., in the thickness of the workpiece at the junction of the steps to have a rounded corner transition; Minimize the hole on the workpiece, groove reinforcement structure asymmetry; The thickness is not uniform parts use the method of reserved processing quantity.

Maintain the operating standard of the corresponding mechanical operating conditions on a regular basis. The contents include monitoring the operation status, replenishment or replacement of lubricants, and inspection of regular disassembly. Maintenance items in operation, bearing rotation sound, vibration, temperature, lubricant state and so on.