High frequency welding is based on the energy of solid resistance heat. The resistance heat generated by high frequency current in the workpiece is used to heat the surface of the workpiece to the melting or near plastic state, and then the metal is combined with or without the imposition of the top forging force. Therefore, it is a method of solid phase resistance welding. High frequency welding can generate heat in the workpiece according to the high frequency current. It can be classified as contact high frequency welding and induction high frequency welding. High frequency welding, high frequency The current flows into the workpiece through mechanical contact with the workpiece. During induction high frequency welding, the high frequency current is coupled by the external induction ring of the workpiece. Induction current is produced in the workpiece. High frequency welding is a professional and strong welding method, and it should be equipped with special equipment according to the product. High productivity, The welding speed is up to 30m/min. It is mainly used for welding longitudinal joints or spiral joints in pipes.