The power frequency adopts the principle of induction heating and is suitable for on-line annealing and preheating of various metal conductors. In the production line, the adhesion between the outside and the conductor can be obviously improved. During the preheating process, the preheating temperature of more than 100 makes the water on the conductor evaporate, the molecular structure of the object is activated and soft, and the quality of the external brightness, bubble and attachment structure is obviously improved. Compared with the oven heating pipe heating equipment, it saves more than 60% electricity. By using the induction heating principle, the electric spark damage to the wire rod is less, the resistance to the preheating conductor is small, it is not easy to stretch, and the output preheating automatic speed tracks to ensure the consistency of the temperature when the wire speed is different. Its appearance is beautiful, the use is convenient, the performance is stable, the price is economical, at present is the cable manufacturer uses the most extensive equipment.