The intermediate frequency bend is an advanced bending method. However, if the pipe bending process is improper, the flabby damage may occur. This kind of damage is shown as a fine grain boundary crack, which has a certain adverse effect on the mechanical properties and service life of the pipe. The heating scope of the central frequency bend is narrow, the internal and external temperature of the pipe wall is uneven, and the pipe material is subjected to sudden and cold flash heat during the bending process, which is its inherent weakness. The central frequency bending tube is mainly used for heating straight pipe and seamless steel tube, which can be produced when the medium frequency is heated.

Features of middle frequency bending tube:

1. The middle frequency elbow adopts the power of the external characteristic, and the positive polarity is adopted in dc.

2. The intermediate frequency bending tube is suitable for welding of thin plates with less than 6mm. It has the characteristics of beautiful weld forming and small welding deformation

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

4. Welding arc length. When welding normal steel, it is better than 2~ 4mm. When welding stainless steel, it is better than 3mm.

5. In order to prevent the appearance of welding pores, the welding parts should be cleaned with rust and oil.

6. The length of the tungsten electrode protruding from the nozzle of the gas is 4~ 5mm, and it is 2~3mm in the area of shading, such as Angle welding, 5~6mm in the depth of the slot, and no more than 5mm from the nozzle to the work.

7. To prevent oxidation of the back of the bottom welding road, the gas protection should also be carried out on the backside of the pipe.

8. Windproof and ventilation. Where there is wind, please take measures to prevent the network, while indoor should take appropriate air ventilation measures.

9, intermediate frequency bend for the argon gas protection welding molten pool very well, and facilitate the welding operation, the center line of the tungsten electrode and welding workpiece generally should maintain 80 ~ 80 ° Angle, Angle of filler wire and workpiece surface should be as small as possible to 0 ° or so commonly.