The camshaft uses a high-frequency induction quenching machine for quenching heat treatment. What are the magnetic field shielding devices used on the inductor?

The camshaft has several cams, main shaft diameters, gears and eccentric wheels on one shaft, which need to be induction hardened using a high-frequency induction hardening machine. However, the distance between them is close. If an ordinary induction is used for quenching, it will inevitably Affect each other's hardness, so the sensor must be protected by a magnetic field shielding device.

There are three types of magnetic field shielding devices.

1. Copper ring shielding method. The copper ring shielding method is to add mica sheets or bakelite boards on both sides of the sensor, and add a copper ring made of copper pipe or copper plate on the outside. The principle is that the magnetic field lines passing through the copper ring will generate an induced current, and the magnetic field lines generated by the induced current are in the opposite direction to the magnetic field lines generated by the high-frequency current on the effective ring, so the escaping magnetic field lines are weakened or offset, and the cams or spindle diameters on both sides are The edges are not heated.

2. Low carbon steel ring shielding method. Similar to the copper ring shielding method, a steel ring made of mild steel or industrial pure iron is installed. Its working principle is that the relative magnetic permeability of the steel ring or pure iron ring is higher than that of air, which attracts or restrains the escaping magnetic lines of force, thus protecting the edges of adjacent cams or spindle diameters from heating. There is information on using them at the same time. Two shielding methods work better.

3. Silicon steel sheet shielding method. That is, a circle of silicon steel sheets is stuck on the outside of the effective circle, and after phosphating treatment, it also has a good shielding effect.