For the manufacture of seamless steel tubes, the corresponding annealing treatment must be carried out after each cold drawing.
Purpose of annealing:
1. Reduce hardness and improve machinability.
2. Eliminate residual stress, stabilize size, reduce deformation and crack tendency.
3. Refine the grains, improve the structure, and eliminate the defects of the structure.
4. Homogenize material organization and composition, improve material properties and prepare for subsequent heat treatment. The seamless steel pipe annealing furnace is to heat the steel pipe to a temperature slightly higher than Ac1, and after holding for a certain period of time, it is cooled to 550°C ~ 600°C and the heat treatment process with air cooling is called stress relief seamless steel tube annealing.
The seamless steel tube annealing furnace adopts an intermediate frequency heating device, which is specially designed for the seamless steel tube continuous annealing furnace. According to the characteristics of its heating in motion and the characteristics of the heated workpiece being a seamless steel pipe, the intermediate frequency power supply and the parameters of the inductor are designed in the system. Special design, the whole set of seamless steel tube annealing furnace production line equipment system is controlled by a separate power supply, and the performance is stable.
Seamless steel tube annealing furnace inductor manufacturing process:
The ratio of the inner diameter of the inductor coil to the outer diameter of the workpiece is within a reasonable range, and is designed according to the process parameters of the induction heating furnace provided by the user. The inductor coil is made of large cross-section T2 rectangular copper tube after annealing, winding, pickling, water pressure test, baking, drying, knotting, assembly and other major processes, and then fixed as a whole, the entire inductor is completed. After forming into a rectangular parallelepiped, its vibration resistance and integrity are good. Both ends of the inductor are protected by copper plates at the mouth of the water-cooled furnace, which can effectively prevent electromagnetic radiation from harming the operator.