Spot stress relief tempering is commonly known as Spot annealing. The hardness of the bearing ring is 59HRC-64HRC, which has higher abrasiveness and higher contact fatigue strength.
This annealing process is used at the surrounding of the set screw hole on insert ball bearing or the eccentric extended ring location of the bearing insert which need to fixed with eccentric locking collar, and other positions on bearing such as the raceway and bearing ring surface remain relatively higher heat-treatment technology.
The hardness does not affect the normal load rating of the bearing. by Spot annealing, the detailed hardness is controlled at 50±5HRC, and GJP normally control at around HRC49 to HRC50, which is not more than HRC50, while reducing the hardness to avoid the breaking after fixing the set screw or Eccentric locating collar.
Completely release and improve spot toughness. the surrounding location on the set screw hole can withstand relatively large tightening torque without cracking; with eccentric locating collar
The outer spherical ball bearing can ensure that the bearing fits well with the eccentric sleeve during operation and reduce the failure rate.