High frequency straight seam steel pipe manufacturing process

　　High frequency straight seam steel pipe is based on the electromagnetic induction principle and ac charge in the conductor skin effect, near effect and eddy current heat effect, so that the weld edge of the steel locally heated to molten state, through the roller extrusion, so that the butt weld to achieve indirect crystal, so as to achieve the purpose of weld welding. High frequency welding is a kind of induction welding (or pressure contact welding), it does not need welding filler, no welding splash, narrow welding heat affected zone, beautiful welding forming, welding machinery function is good, so it is widely used in the production of steel pipe.

　　The high-frequency welding of the steel tube is the use of skin effect of alternating current (ac) and the adjacent effect, steel (strip) after rolling forming, form a cross section of broken circular tube billet, in the middle of the tube billet inside near the induction coil rotating around one or a set of impedance (magnet) and impedance and tube billet was reluctant to form an electromagnetic induction loop, under the action of skin effect and the adjacent effect, A strong and concentrated thermal effect is produced at the edge of the opening of the billet, which makes the edge of the weld rapidly heated to the temperature required for welding. After extrusion by the press roller, the metal in the molten state realizes indirect crystallization and forms a firm butt weld after cooling. High frequency straight seam steel pipe manufacturing process.