1 the use of vertical external characteristics of the power supply, the use of positive polarity (welding wire electrode)
2 is generally suitable for the welding of 6mm sheet metal, has the characteristics of weld appearance, small welding deformation.
3 the gas is argon and the purity is 99.99%. When the welding current is 50~50A, the argon flow rate is 8~0L/min, when the current is 50~250A, the argon flow rate is 2~5L/min.
4 tungsten electrode from the gas nozzle to highlight the length of the 4~5mm is better, in the corner welding, such as poor shelter is 2~3mm, in the deep groove depth is 5~6mm, the nozzle to the working distance is generally not more than 5mm.
5 in order to prevent the emergence of laser welding, welding parts such as rust, oil, make sure clean.
6 welding arc length, welding of ordinary steel, the 2~4mm is better, and the welding of stainless steel, to ~3mm for the best, too long, the protective effect is not good.
The 7 docking base, in order to prevent the bottom bead back is oxidized back, also need to carry out gas protection.
8 for argon to make a good protection of weld pool, and facilitate welding operation, tungsten electrode center line and welding workpiece should remain generally 80 ~ 85 degrees, filling should be small as possible for the angle between the wire and the workpiece surface, generally around 0 degrees.
9 wind and ventilation. Where there is wind, please take the measures to stop the network, and the appropriate ventilation measures should be taken in the room.
Points of MIG welding of stainless steel pipe and matters needing attention:
1 using the constant voltage welding power supply, DC reverse polarity (wire connected to the positive electrode)
2 general use of pure argon (purity of 99.99%) or Ar+2%O2, flow to 20~25L/min is appropriate.
3 arc length, stainless steel MIG welding, generally in the injection of the transition conditions down the welding, the voltage to be adjusted to arc length in the degree of 4~6mm.
4 wind. MIG welding is easy to be affected by the wind, and sometimes the breeze and the air holes, so the wind speed in the 0.5m/sec above places, should take measures to wind.
Key points of welding flux cored wire for stainless steel pipe and points for attention:
1 using the constant voltage welding power supply, DC welding by reverse polarity. The use of general CO2 welding machine can be applied, but the pressure of the wire feed wheel, please slightly.
2 the protection gas is generally the carbon dioxide gas, the gas flow by 20~25L/min is more suitable.
3 the distance between the nozzle and the workpiece is suitable for 5~25mm.
4 dry stretch length, the general welding current is about 250A below 5mm, about 250A when 20~25mm is more appropriate.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)
