High Frequency Soft Welding Tube Ferrite Rod - China Suppliers & Factory for Pipe Mill Machines

A Hf welding pipe mill machine mainly consists of the following parts: a high-frequency (coil), the steel tube to be welded, a ferrite rod (magnetic rod), squeeze rolls, and a water cooling system.

Its operation follows a strictly electromagnetic induction principle: When high-frequency current flows through the induction coil, a high-frequency alternating magnetic field is generated. As a high-permeability magnetic path, the magnetic rod which is placed inside the pipe actively guides and concentrates the magnetic flux lines, focusing them precisely along the weld seam edges. At this location, strong eddy currents are induced by the dense magnetic flux, instantly generating heat sufficient to melt the metal. The squeeze rolls then apply pressure to finish the welding process.

To effectively increase the magnetic flux in the induction coil, the magnetic rod must have a high magnetic permeability. Since permeability is a function of the magnetic field strength H, it is particularly required to be high within the range of magnetic fields used in the welding process. Because most welding machines operate under relatively low magnetic field strength, the initial permeability is typically used as a measure of this property.

When the alternating magnetic field generated by the coil becomes too strong, the magnetic rod can reach magnetic saturation. At this point, if the alternating magnetic field continues to increase, the magnetic rod will lose its efficiency for further increase. Therefore, for large-power pipe welding units, it is necessary to pay attention to using magnetic rods with high saturation flux density (also known as saturation magnetic induction strength).