Induction heating surface quenching is a quenching method that uses the principle of electromagnetic induction to make the parts cut the magnetic line in the alternating magnetic field, generate induction current on the surface, and quickly heat the surface of the part in the form of vortex, and then heat cold.It occupies an important position in the field of heat treatment, and this technology has been widely used in our country.
Selection of quenching heating frequency of induction heating surface:
The relationship between the depth of 8 (mm) into the surface of the workpiece and the current frequency f (HZ) at room temperature is the increased frequency, the current penetration depth, and the quenching layer
Commonused current frequencies are:
1. High frequency heating: 100~500KHZ, commonly used 200~300KHZ, is high frequency tube heating, the quenching layer is 0.5~2.5mm, is suitable for small and medium-sized parts.
2. Medium frequency heating: the current frequency is 500~10000HZ, commonly used 2500~8000HZ, the power equipment is mechanical medium frequency heating device or silicon controlled medium frequency generator, quenching layer depth of ~10 mm, suitable for large diameter shaft and large gear, etc
3. Power frequency heating: the current frequency is 50HZ.Mechanical working frequency heating power equipment, the quenching layer depth of 10~20mm, suitable for surface quenching of large diameter workparts.
The application of induction heating surface quenching and ordinary additive control fire have:
1. The additive speed is very fast, which can expand the transition temperature range of the A body and shorten the transition time
2. After quenching, extremely fine cryptocrystalline martenite can be obtained on the surface layer, with slightly higher hardness (2~3HRC), low fragility and high fatigue strength
3. The artifact is not easy to oxidation and decarbonize, and can be directly assembled and used after some butyl outsourcing,
4. Control the deep hard layer, easy to dry control, easy to dry to achieve mechanization and automation.