Why is the efficiency of high-frequency quenching equipment high?

Why is it necessary to cool quickly after induction hardening?
The advantages of induction hardening technology, such as fast heating speed, high production efficiency, energy conservation, environmental protection, and ease of mechanization and automation, have been widely recognized and applied in the mechanical manufacturing industry, especially in the automotive manufacturing industry.

For a long time, people have attached sufficient importance to the heating technology in induction hardening, and have done a lot of work (such as sensor structure design and process parameter research (frequency, power, heating time, etc.), and achieved good results. People can obtain an ideal heat shape and suitable quenching temperature. However, cooling technology is often not given much attention or even ignored, resulting in some quality issues with quenching processes, such as insufficient hardness, uneven hardness, and quenching cracks.

In view of this situation, Wanling High Frequency has put forward some opinions and discussed with peers on the cooling technology issues in induction hardening.

Why is it necessary to cool quickly after induction hardening?

As is well known, induction hardening is generally used for surface layer quenching of mechanical parts. By using induction heating, the surface layer of a certain part of a steel component is rapidly heated to the quenching temperature, and then rapidly cooled and quenched (usually by spray cooling quenching) to obtain a high hardness martensitic structure on the surface layer. However, other heating methods, due to their slow heating speed, cannot achieve surface layer heating and are even more difficult to achieve rapid cooling, naturally unable to achieve surface layer quenching. The microstructure and properties of undercooled austenite transformation products vary at different cooling rates.

After completing induction heating, it is necessary to cool extremely quickly to prevent the low-temperature core from absorbing the heat of the surface layer and causing non martensitic transformation of the surface layer. Therefore, the cooling of induction quenching must be rapid cooling.