What should I pay attention to when welding
seamless steel pipe? The following is the explanation of the staff of seamless steel pipe manufacturer, I hope to help you.
1. When the butt is bottomed, in order to prevent the back side of the bottom bead from being oxidized, gas protection is also required on the back side.
2. In order to prevent the occurrence of the welding holes of the special-shaped pipe, the welding parts must be cleaned if there is rust or oil.
3. Dry elongation, the general welding current is about 5mm when the temperature is below 250A, about 20-25mm above 250A is more suitable.
4. It adopts flat characteristic welding power source, and reverse polarity is used for DC welding. The welding can be carried out using a general CO2 welder, but the pressure of the wire feed wheel should be slightly loosened.
5. Arc length, MIG welding of stainless steel shaped tube, generally under the conditions of jet transition welding, the voltage should be adjusted to the arc length of 4-6mm.
6. Shaped tube MIG welding is susceptible to wind, and sometimes breeze creates pores. Therefore, wind speed should be taken in places where the wind speed is above 0.5m/sec.
7. The length of the tungsten electrode protruding from the gas nozzle is preferably 4-5 mm, 2-3 mm in the place where the shielding property such as fillet welding is poor, and 5-6 mm in the deep groove.The distance from the nozzle to the work is generally no more than 5mm.
8. In order to make the argon gas protect the weld pool well and facilitate the welding operation, the tungsten center line and the welding workpiece should generally maintain an angle of 80-85°, and the angle between the filler wire and the profiled tube surface should be as small as possible. It is generally around 0°.
9. When the DC is used, the positive polarity is generally suitable for the welding of the special-shaped tube below 6mm. The welding is beautiful, and the welding deformation is small. The shielding gas is argon, and the purity is 99.99%. When the welding current is 50-50A, the argon flow rate is 8-0L/min, and when the current is 50-250A, the argon flow rate is 2-5L/min.
