The heating ring has high temperature and concentrated energy

The high temperature generated by the arc is used to heat the object. An arc is a gas discharge between two electrodes. The voltage of the arc is not high but the current is large, and its strong current is maintained by a large number of ions evaporated on the electrode, so the arc is easily affected by the surrounding magnetic field. When an arc is formed between the electrodes, the temperature of the arc column can reach 3000-6000K, which is suitable for high-temperature melting of metals.
There are two types of arc heating, direct and indirect arc heating. The arc current of direct arc heating passes directly through the object to be heated, and the object to be heated must be an electrode or medium of the arc. The arc current of indirect arc heating does not pass through the object to be heated, but is mainly heated by the heat radiated by the arc. The characteristics of arc heating are: high arc temperature, concentrated energy, and the surface power of the steelmaking electric arc furnace melting pool can reach 560-1200 kW/square meter. However, the noise of the arc is large, and its volt-ampere characteristic is a negative resistance characteristic (drop characteristic). In order to keep the arc stable during arc heating, the instantaneous value of the circuit voltage is greater than the arc starting voltage when the arc current crosses zero instantaneously, and at the same time, in order to limit the short-circuit current, a resistor of a certain value must be connected in series in the power circuit.
The surface of the object is bombarded by electrons moving at high speed under the action of an electric field to make it heated. The main component for electron beam heating is the electron beam generator, also known as the electron gun. The electron gun is mainly composed of cathode, focusing pole, anode, electromagnetic lens and deflection coil. The anode is grounded, the cathode is connected to the negative high position, the focused beam is usually at the same potential as the cathode, and an accelerating electric field is formed between the cathode and the anode. The electrons emitted by the cathode are accelerated to a very high speed under the action of the accelerating electric field, focused by the electromagnetic lens, and then controlled by the deflection coil, so that the electron beam shoots to the heated object in a certain direction.
The advantages of electron beam heating are: ① Controlling the current value Ie of the electron beam can change the heating power conveniently and quickly; ② Using the electromagnetic lens can freely change the heated part or freely adjust the area of the electron beam bombardment part; ③ It can Increase the power density so that the material at the bombardment point is evaporated in an instant.