The heat treatment of bearing rings is the core process that determines the accuracy, hardness, wear resistance, and service life of bearings. It is necessary to focus on preventing the following key issues that affect quality:
1. Prevent uneven/insufficient hardness
Risk: Uneven heating temperature and insufficient insulation time may result in local hardness of the ring not meeting the standard, directly reducing the wear resistance of the bearing;
Response: Adopting precise temperature control continuous heating equipment, setting a matching heating curve according to the ring material (such as bearing steel GCr15) to ensure uniform temperature penetration, while strictly controlling the insulation time.
2. Avoid deformation exceeding the tolerance limit
Risk: Uneven stress release during heat treatment can easily cause the ring to become elliptical and warped. If subsequent grinding cannot be corrected, it can directly lead to abnormal clearance during bearing assembly;
Response: Optimize the furnace loading method (such as layered placement and use of specialized fixtures), adopt the "preheating+graded cooling" process, and reduce the combined effects of thermal stress and tissue stress.
3. Eliminate organizational defects
Risk: Improper cooling rate can easily produce undesirable structures such as network carbides and residual austenite, reducing the toughness and fatigue strength of the ring, and long-term use can lead to cracking;
Response: Match cooling media (such as oil cooling and air cooling) for different specifications of rings, strictly control the cooling rate, and stabilize the organizational state through tempering process.
4. Prevent surface oxidation/decarburization
Risk: Improper protection during the heating process may result in the formation of oxide or decarburization layers on the surface of the ring, weakening the surface hardness and wear resistance, and shortening the bearing life;
Response: Use controlled atmosphere furnaces or vacuum heating equipment to isolate air contact, and at the same time, perform protective treatment (such as coating protection) on the surface of the ring before loading into the furnace.
