The high-frequency welding process of submerged arc steel pipe

The high-frequency welding process of submerged arc steel pipe

1. Control of the weld gap:

After rolling by multiple rollers, the strip steel is sent to the welded pipe unit. The strip steel is gradually rolled up to form a round tube blank with a tooth gap. Adjust the pressing amount of the squeeze roll to control the weld gap between 1 and 3 mm and make the weld ends flush.

2. Welding temperature control:

It is necessary to change the capacitance, inductance, or voltage and current in the circuit to change the size of the encouraging frequency, and then reach the goal of controlling the welding temperature. Regarding low-carbon steel, the welding temperature is controlled at 1250~1460℃, which can meet the tube wall thickness of 3~5mm welding. Through requirements. The welding temperature can also be completed by adjusting the welding speed.

Three, the restraint of squeezing force:

Under the extrusion of the squeeze roller, the two edges of the tube blank are heated to the welding temperature. The metal crystal grains formed together to penetrate and crystallize each other and finally form a strong weld.

Fourth, the adjustment of the position of the high-frequency induction coil:

The heating time is longer, and the high-frequency induction coil should be as close as possible to the squeeze roller. If the induction loop is far away from the squeeze roller. The heat-affected zone is wider, and the strength of the weld is reduced; on the contrary, the edge of the weld is lacks heating, and the shape after extrusion is poor.

6. Weld scars will occur after welding and extrusion. Relying on the rapid movement of the welded pipe, the weld scar will be flattened. The burrs inside the welded pipe are generally not cleaned.