Function and application of magnetic bar in high frequency welding
When the high-frequency current passes through the induction coil, the high-frequency magnetic flux will be generated in the coil, and the eddy current induced by the high-frequency magnetic flux in the welded pipe will melt the weld for welding. The use of magnetic rods can increase the magnetic flux in the induction coil, thereby increasing the welding power. At the same time, the placement of the magnetic rod makes the magnetic flux in the induction coil concentrated in the contact strip, and the magnetic flux between the induction coil and the welded tube is relatively reduced, thus improving the welding efficiency.
1. The high-frequency pipe welding machine is mainly composed of the following parts: high-frequency inductor (coil), steel pipe to be welded, strong magnetic rod, extrusion roll, water cooling equipment.
2. Working principle of the high frequency welding magnetic bar: When the high frequency current passes through the induction coil, the high frequency magnetic flux will be generated in the coil, and the eddy current induced by the high frequency magnetic flux in the welded pipe will melt the weld for welding. When the magnetic rod is not placed in the welding tube, the magnetic flux generated by the induction coil is :N is the permeability of the vacuum, H is the magnetic field strength, and S is the cross-sectional area of the coil. The magnetic rod can increase the magnetic flux in the induction coil, so as to increase the induction electromotive force in the welded pipe and improve the welding power. More importantly, the placement of the magnetic rod makes the magnetic flux in the induction coil concentrate in the contact strip, and the magnetic flux between the induction coil and the welded tube is relatively reduced, thus improving the welding efficiency.
3. In order to effectively increase the magnetic flux in the induction coil, the magnetic permeability of the magnetic rod must be very high. Considering that it is a function of the magnetic field H, it is particularly required that the permeability should be high in the range of the magnetic field used. Because the magnetic field of various welders is not high. At present, the original permeability is usually used to measure this quantity. When the alternating magnetic field generated by the induction coil is too large, the magnetic rod will reach saturation magnetization. At this point, if the alternating magnetic field increases further, the magnetic bar will lose its further increased efficiency. Therefore, for high-power welded pipe units, attention should be paid to the use of magnets with high saturated magnetic flux density (also known as saturated magnetic induction intensity). 4. Correct selection and use of magnetic rods In recent years, the research and production of high frequency welding magnetic rods in China has developed rapidly. In particular, the establishment of individual professional manufacturers, committed to the research and development of the product, accelerated the development process.
