What matters when high speed welding the steel pipe

In terms of the welded steel pipe at processing, the main problem needed to be solved is: the welder should deliver enough energy to the V-weld pipe area. This transfer of energy is achieved by the magnetic field produced during operation of the welder, and conducted through the impedance. Its magnetic field vector is increased with the increasing of the required welding power (rolling speed×wall thickness). And the magnetic flux of the impedance is affected by the strength of the saturation magnetic flux of ferrite, the total cross-sectional area and temperature. With the V-shaped area of welding flux (V-type area of×V-shaped opening) of decreases. Based on the above theory, this welded steel pipe at high speed, executing the following specifications is necessary:

1.Use a large diameter resistor as much as possible. End solid shape is superior to hollow circle.

2. Provide sufficient cooling water - at least 4 gallons per minute (US), best reaching 5 gallons per minute. Because water line near the impedance is small and easy for blockage, it must ensure that the cooling water is very clean. In addition, the housing of the impedance can senseg heat, which will result in the accumulation of the metal particles and the destruction of the housing and ferrite.

3. Place the resistor correctly (from the apex 1/8 " of the V-shaped area). If choose from the available small impedance and meeting the specification requirements, the requirements of the specification should be preferred.

4. Place the roll as close to the welding squeeze roll as possible, from its approximately 1/4 to 1/2, and guarantee that its center perpendicular to the rolling axis .

5. When molding the hfw steel pipe, shaped with large diameter as much as possible; then reducing in the sizing section. Optimum pipe diameter is preferably formed of 0.695. "

6.Correct positioning of material holder can obtain the minimum length of a V-shaped mouth, and can make the weld squeeze rollers heated to a minimum. The size of the V-shaped mouth should be 2 times the diameter or slightly less. Between two rollers at the top, and it will give the minimum length of the V-shaped mouth.