Digital brazing machine

Brief introduction of induction brazing:

Welding method using high frequency, medium frequency or power frequency induction current as heat source. High frequency heating is suitable for welding thin-walled pipe fittings. The coaxial cable and split type induction ring can be brazed in the field far away from the power supply, especially suitable for the welding of some large components, such as the pipeline joints to be disassembled on the rocket.

Induction brazing applications:

During induction brazing, the brazing part of the part is placed in the alternating magnetic field, and the heating of the base metal is realized by the resistance heat of the induction current generated in the alternating magnetic field. The intensity of the induced current in the conductor is directly proportional to the frequency of the alternating current. With the increase of the frequency of the alternating current used, the induced current increases and the heating speed of the weldment becomes faster. Based on this, most induction heating uses high-frequency alternating current. However, the higher the frequency, the smaller the depth of current penetration. Although the surface layer is heated rapidly, the thickness of the heating is thinner. The interior of the part can only be heated by the heat conduction from the surface layer to the inside, which is the so-called skin effect. It can be seen that it is not advantageous to select a high frequency of alternating current. Generally, the frequency of about 500KHz is more appropriate. In addition, the skin effect is also related to the resistance coefficient and permeability of the material. The larger the resistance coefficient is, the smaller the permeability is, the weaker the skin effect is; otherwise, the skin effect is more significant. Induction coil is an important part of induction brazing equipment. The basic principle of correct design and selection of induction coil is to ensure the heating speed, uniformity and high efficiency in welding year.

Generally, the induction coil is made of pure copper tube, and the pipe is cooled by water during operation. The thickness of the pipe wall should be less than the current penetration depth, generally 1 ~ 1.5mm. The gap between the induction coil and the weldment should be kept to avoid short circuit. However, in order to improve the heating efficiency, the gap between the induction coil and the weldment should be reduced as much as possible. During induction brazing, some auxiliary tools are often needed to clamp and locate the weldment. When designing the fixture, it should be noted that the fixture parts adjacent to the induction ring should not use metal to avoid induction heating. In induction brazing, foils, filaments, powders and pastes can be used. The filler metal should not form a closed ring, but flux and gas medium can be used to remove the film. Induction brazing is widely used to braze steel, copper and copper alloy, stainless steel, high temperature alloy and other symmetrical shape weldments, especially for pipe fitting, pipe and flange, shaft and sleeve joints; for aluminum alloy brazing, due to the temperature is not easy to control, this method is not suitable