1. Use a reasonable cooling method:
The influence of the cooling process on the deformation after metal quenching is also a very important cause of deformation. Hot oil quenching is less deformed than cold oil quenching and is generally controlled at 100±20°C. The cooling capacity of the oil is also crucial to deformation. The quenching stirring method and speed all affect the deformation. The faster the cooling rate of the metal heat treatment, the more uneven the cooling, the greater the stress generated, the greater the shape of the mold into the import bearings. It is possible to use precooling on the premise of ensuring the hardness requirements of the mold; the use of fractional cooling quenching can significantly reduce the thermal stress and tissue stress generated during metal quenching, which is an effective method to reduce the deformation of some complex shapes with relatively complex shapes; For workpieces with higher accuracy requirements, isothermal quenching can significantly reduce distortion.
2. Use a suitable medium:
Under the premise of ensuring the same hardness requirements, try to use oily medium. Experiments and practice have proved that under the premise of no other conditions, the cooling speed of oily medium is slower, and the cooling rate of aqueous medium is relatively faster. Moreover, compared with the oily medium, the change of the water temperature has a greater influence on the cooling characteristics of the aqueous medium. Under the same heat treatment conditions, the deformation of the oily medium after the quenching of the aqueous medium nsk bearing is relatively small.
3. Parts structure should be reasonable:
After the metal heat treatment, during the cooling process, the thin part is always cold and the thick part is cold. In the case of meeting actual production needs, the thickness and thickness of the workpiece should be minimized, and the section of the part should be uniform in order to reduce the distortion and cracking tendency of the transition zone due to stress concentration; the workpiece should try to maintain the symmetry of structure and material composition and organization to reduce Due to uneven cooling caused by distortion; workpieces should be avoided as much as possible sharp corners, grooves, etc., in the workpiece at the thickness of the junction, the step should have a fillet transition; as much as possible to reduce the workpiece on the hole, groove rib structure asymmetry; uneven thickness The part adopts the method of reserved processing volume.
