Channel Brazing Hardening Inductor

1. Induction heating (Induction Heating) basic principles

Induction heating is a method of non-contact heating of conductive materials using the principle of electromagnetic induction. The core principle is:

Alternating Magnetic Field Generation: When alternating current (AC) passes through a coil (called an induction coil or inductor), an alternating magnetic field is generated around it.

Eddy current effect: When a conductive workpiece (e.g. metal) is placed in this alternating magnetic field, induced currents are generated inside the workpiece, which are called “Eddy Currents”.

Joule heat effect: When eddy currents flow inside a workpiece, heat is generated due to the resistance of the workpiece itself (P=I). 

2R, where P is the power, I is the current and R is the resistance), which causes the workpiece to heat up rapidly.

Hysteresis loss (for magnetic materials): For ferromagnetic materials (e.g., iron, steel), in addition to the eddy current effect, the magnetic field in the material repeated internal magnetization and demagnetization process will produce hysteresis loss, which will also be converted into heat, especially in the material to reach the Curie point (the temperature of loss of magnetism) before the hysteresis loss is one of the main heating methods.

The advantages of induction heating include: fast heating speed, high efficiency, localized heating, easy control and automation, no open flame, and environmentally friendly.

2. Channel type inductor (Channel Type Inductor)

The inductor is the key component of the induction heating equipment to generate alternating magnetic field. It is usually made of hollow copper tubing wound with water cooling to prevent it from overheating. The shape and size of the inductor is customized according to the shape and size of the part to be heated and the required heating zone.

A “channel inductor” is a specific geometry of an inductor. As the name implies, it usually forms a “channel” or “slot” shape that allows the workpiece to pass through it for continuous or intermittent heating. This design is suitable for:

Continuous production lines: e.g. continuous heating of long bars, wires, tubes, etc.

Specific Zone Heating: When only a specific narrow zone of the workpiece needs to be heated, the channel inductor can provide concentrated heat.

Automated operation: Easily integrated with automated conveyor systems for efficient production.

3. Application in Brazing

Brazing is a method of joining two or more metallic materials by using a filler metal (brazing material) with a melting point lower than that of the base material, heating it above the melting point of the brazing material, melting it and filling it into the joint gap, forming a strong connection through wetting and diffusion.

In induction brazing, channel type inductors can be used for:

Precise localized heating: Accurately heat the joint area to be brazed, causing the brazing material to melt and flow while minimizing the impact on the surrounding base material.

Increased productivity: particularly suitable for brazing operations in mass production or on continuous production lines, e.g. for joining automotive components, refrigeration lines, etc.

Improved brazing quality: Induction heating provides fast, uniform heating, which helps to minimize oxidation and distortion, and improves the quality and strength of brazed joints.

4. Application in Hardening

Hardening is a heat treatment process designed to increase the hardness, wear resistance and fatigue strength of a material by heating a metal (usually steel) above the austenitization temperature through rapid cooling and then rapidly cooling it to cause a martensitic phase transformation.

In induction hardening, channel-type inductors can be used:

Surface quenching: The “skin effect” characteristic of induction heating causes the high-frequency current to concentrate mainly on the surface of the workpiece, thus realizing rapid heating and quenching of the surface of the workpiece, while the core remains relatively ductile. Channel-type inductors allow continuous or scanning quenching of specific surface areas of long shafts, gears, cams, etc.

Improved wear resistance: By forming a hardened layer on the surface of the workpiece, the wear resistance is significantly improved, extending the service life of the component.

Controlled distortion: Due to the short heating time and precisely controlled heating zones, induction hardening usually causes less distortion than general heating hardening.

Automation and repeatability: Easily automated production ensures consistency and repeatability of the quenching process.

Summary

Thus, the term “Channel Brazing Hardening Inductor” refers to a channel-type induction coil designed for brazing (joining metal parts) or hardening (increasing surface hardness) workpieces by means of induction heating. These inductors are typically used in production lines or automated processes where localized, rapid, and precise heating of specific areas is required to achieve