High frequency induction brazing
Induction brazing is to place the metal workpieces that need to be welded (usually mostly copper) in the induction coil, pass high-frequency alternating current, generate an induced electromagnetic field, and generate an induced electromotive force on the surface of the workpiece to form an induced eddy current on the metal surface, which is generated on the metal surface. The eddy current heat is generally applied to the welding site, and the welding powder can be welded until the workpiece reaches the melting temperature of the brazing material. Induction brazing is currently the most clean and environmentally friendly heating welding method in the world. This kind of welding is widely used in the copper bar rotor, because the welding simultaneously performs several simultaneous operation of the welding points, the process parameters are consistent, and the deformation of the welding points is effective, regardless of work efficiency, reliability and beauty. Many aspects are a better process, but because the equipment cost is relatively high, the cost of the corresponding induction coil is also very expensive, so not every manufacturer uses this welding technology.
Medium frequency induction brazing
The medium frequency induction brazing equipment is to assemble the surface-cleaned workpieces in an overlapping manner, and place the brazing material near the joint gap or between the joint gaps.
The medium frequency induction brazing equipment can replace the aging heating means such as oxyacetylene heating, coal oven heating, and box type electric furnace heating to perform brazing and quenching heat treatment. It can greatly improve product quality, effectively save energy and improve working conditions. When the workpiece and the brazing material are heated to a temperature slightly higher than the melting point of the brazing filler metal, the brazing material melts (the workpiece is not melted), and is sucked into and filled with the gap between the solid workpieces by capillary action, and the liquid brazing material and the workpiece metal mutually diffuse and dissolve. A brazed joint is formed after the cold.
Characteristics of medium frequency induction brazing equipment: 1. Since the principle of medium frequency induction heating is electromagnetic induction, the heat is generated by the workpiece itself. The heating method has a fast heating rate, little oxidation, high heating efficiency, good process repeatability, and metal surface. Only a slight discoloration, a slight polishing can restore the surface to a mirror finish, effectively achieving consistent material properties. 2, uniform heating, high temperature control accuracy, uniform heating, to ensure that the temperature difference between the heating core table is small. Through the temperature control system, the temperature can be accurately controlled to ensure product repeatability.
There are many applications for the welding of the bare copper strip rotor bar of the medium frequency induction brazing. The welding method is more demanding on the cutting and forming of the guide bar and the shape of the head cover related thereto, otherwise the welding effect will be greatly reduced.
Based on the above information content, each motor manufacturer should conduct comprehensive evaluation based on their respective equipment characteristics and product characteristics, but the reliability of welding quality is the key technology for manufacturing.
