Measures to reduce the deformation hardening of bearing rings
Deformation of the bearing rings after heat treatment can be broadly divided into three categories: The first category is the diameter variation (Vpe), second class level
Average diameter variation (Vdmp), the third category is the flatness of the change (Ape), these three deformation often overlap, in which straight
Diameter most prone to change, and the amount of variation is large, and therefore to control the deformation hardening, the main change is to try to reduce the diameter of the ferrule
the amount. A ferrule deformation hardening factor a, the organization after the original organization bearing steel annealing of defects and resulting in large carbides
Small, uneven distribution will lead to deformation hardening. b, quenching thermal stress and the greater the stress, the greater the deformation hardening.
Thermal stress and force includes: heating temperature, heating rate and uniformity, and uniformity of cooling rate, cooling medium temperature
Degree. c, the ferrule car machining residual stress magnitude and the size of the diameter changes caused by the car processing, are associated with hardening
After the change of the size of the amount, but also in a direction substantially the same. Second, to reduce the ferrule deformation hardening measures a, strict control
Refrigeration but speed and improve the annealing quality. Size ball annealing cooling rate directly affects the carbide shape, size and sub
Divergence, thus affecting the quenching and tempering process to develop, the amount of change in the diameter of its ultimate mechanical properties. Therefore, the correct formulation annealing
At the same time the process, strict control of the cooling rate 10 ~ 25 ℃ / h, make organizational preparations for the final heat treatment. b, strict control of car
Changes in processing rings, can be seen from Table 2-63, after turning closely related to changes in diameter and deformation hardening. Vehicle processing diameter
The larger the amount of fluctuation, the fluctuation amount after quenching from about large diameter, but in a direction substantially consistent. So to control quenched
Changes in the diameter of the heat, the first step should be strictly controlled lathe diameter variation.
