The medium frequency pipe bender adopts the power supply with vertical external characteristics, and the positive polarity (the welding wire is connected with the negative electrode) is adopted when the direct current is applied.

Medium frequency bending pipe is generally suitable for welding of thin plates under 6mm. It has the characteristics of beautiful weld forming and small welding deformation

The protective gas is argon with a purity of 99.99%.When the welding current is 50~50A, the flow rate of argon is 8~0L/min, and when the current is 50~250A, the flow rate of argon is 2~5L/min.

2~4mm is the best welding arc length for ordinary steel, and ~3mm is the best welding arc length for stainless steel. If the welding arc length is too long, the protection effect is not good.

In order to prevent the appearance of welding holes, welding parts such as rust, oil must be cleaned up.

The length of the tungsten electrode protruding from the gas nozzle is 4~5mm. It is 2~3mm in the place of poor shielding such as fillet welding, and 5~6mm in the place of deep grooving. The distance from the nozzle to the work is generally not more than 5mm.

In order to prevent oxidation of the back side of the bottom pass, the back side also needs to be protected by gas when the middle frequency elbow is butted.

Windproof and ventilation.In windy areas, always take measures to stop the net, and take appropriate ventilation measures indoors.

In order to protect the welding pool well with argon gas and facilitate the welding operation, the Angle between the tungsten electrode center line and the workpiece at the welding place should generally be maintained at 80~85°, and the Angle between the filler wire and the workpiece surface should be as small as possible, generally about 0°.

This process can avoid the uneven phenomenon of pipe bend wall thickness caused by the tension thinning of the convex edge of pipe wall and the compression thickening of the concave edge of pipe wall.

By using this process, 180 elbow with uniform wall thickness of small radius (R≈D) and thin wall (T /D≈0.015) can be produced, which cannot be achieved by other bending processes.

If the design of various technological parameters is reasonable, the thickness of the pipe wall in each part of the bending pipe forming process can be kept constant, that is, it is always equal to the thickness of the straight pipe before deformation.

The process can be used to produce 45°, 90°, 180° and other bending angles of the same caliber with the same horn mandrel at one time, and the production efficiency is high.