The general knowledge for welding pipe---several factors that affect welding speed as following:

1.Geometric size for inductor, such as diameter and width and turns for inductor.

2. The distance from inductor forefront to the center of squeeze roller.

3. The size of open angle for steel pipe.

4. The length and location for impedor.

Impedor function in steel pipe welding:

In the process of steel pipe welding, the impedor decreases the HF current which is around the pipe, so that can increases the HF current in the edge of seam and raising heating efficiency as well. In general, the impedor’s cross section area should be 60-70% of inside diameter of the pipe, if the size is less than 60%, it will lead the welding efficiency decreasing obviously. The impedor must has higher initial magnetic permeability, as high curie temperature as possible and lower loss. In the application, an attention must be paid on that the cooling for impedance should be enough to protect from its cracking or fault due to over curie point and temperature being too high. The length and position inside the pipe of impedance might affect the welding efficiency.