Preheating of ① quenching before heating: The main purpose is to shorten quenching heating time, reduce deformation cracking, but also reduce the tendency of overheating and decarbonization, the process using salt bath furnace preheating, temperature is 600 ℃, preheating 8-10 minutes, if the Use of box-type electric furnace preheating, temperature in 530-550 ℃ around the time longer.
② Heating Time Determination: the heating time of each factory is not exactly the same, generally after preheating heating time for 10-15s/mm, box-type furnace for 35-50s/mm. No preheating salt furnace for 30-35s/mm, box-type furnace for 90-100s/mm. In this case, the GCr15 bearing ball after preheating in the salt furnace quenching heating time to take 8 minutes.
③ quenching and Cooling: Because GCR15 bearing ball contains more alloying elements, inhibit the homogenization of components, also in order to prevent GCr15 bearing steel deformation and also have a certain degree of toughness and anti-fatigue strength, so oil cold