Quenching oil is a process oil used as a quenching medium .

The cooling capacity of oil in the range of 550-650℃ is insufficient, and the average cooling rate is only 60-100℃/s, but in the range of 200-300℃, the slow cooling rate is very suitable for quenching. The oil is used for quenching alloy steel and small-section carbon steel, which can not only obtain sufficient hardenability and hardenability, but also avoid cracking and reduce deformation. In order to meet the process requirements of heat treatment, quenching oil should have the following characteristics: ① Higher flash point to reduce the risk of fire; ② Lower viscosity to reduce the loss caused by oil adhesion to the workpiece; ③ Not easy to oxidize and stable performance to slow down aging and extend service life