The selection of cooling method and cooling medium for induction heating quenching is based on comprehensive factors such as steel, part shape and size, induction heating method, etc.
During induction heating, the commonly used cooling methods include immersion cooling method and spray cooling method. Some parts made of alloy steel are cooled by immersion in oil, most parts made of carbon steel and low alloy steel are cooled by spray, while some parts made of alloy steel are cooled by immersion in oil.
The spray cooling method can control the cooling rate by adjusting the water pressure, water temperature and spray time. To avoid quenching deformation and cracking, pre cooling followed by quenching or intermittent cooling can be adopted. During continuous heating and quenching, the pre cooling time can be adjusted by changing the included angle between the water spray hole and the axial direction of the part, or changing the distance between the water spray hole and the part, the moving speed of the part, etc.
For gears made of slender, thin-walled parts or alloy steel, in order to reduce deformation and cracking, the inductor and parts can be put into the oil tank at the same time for heating and cooling after power failure. This quenching method is called oil embedding quenching method.
In order to avoid deformation and cracking, it is generally not cooled to room temperature. When heating at the same time, the cooling time of water spray is generally 1/3 ~ 1/2 of the heating time.