Immediately after the workpiece quenching cooling to room temperature, placed in the environment of the below room temperature for a certain time, take out at room temperature, this processing is lower than the room temperature, is called the cold treatment.Bearing steel refrigerator and dry ice cold treatment often USES alcohol solution.

1. The effect of cold treatment Precision bearing higher requirements for dimensional stability;Ring quenching (especially interrupted quenching), the internal organization remains more residual austenite, the retained austenite is unstable organization, in the process of storage and use of the bearing, will continue to change, to change the accuracy of bearing.For cold treatment technique, it can reduce the residual austenite in the organization, and improve the hardness of parts slightly.

2. The cold treatment process Stay in room temperature after quenching, quenching, be sure to make the ring inside and outside even after cooling to room temperature to cold treatment, otherwise easy to crack, cold treatment immediately after cooling to room temperature (generally no more than 30 min), otherwise it will suspend the austenite to martensite.

Cold treatment temperature: the temperature of the cold treatment mainly according to the steel martensitic transformation to end temperature Mf, also consider the effect of cold treatment on the mechanical performance and manufacturability. For GCr15 steel, cold treatment is chosen - 70 ℃;Not very high accuracy ring or equipment limited, optional for cold treatment temperature - 40 ~ 70 ℃;Ultra precision bearing, can be in - between 70 ℃ ~ 80 ℃ cold treatment.Too cold temperature affect bearing impact and contact fatigue life.

Cold treatment insulation: although a lot of martensitic transformation is a temperature in the cold