Matters Needing Attention about Welding Stainless Steel Pipe

Jun 12, 2020

The development of steel pipe technology began with the rise of bicycle manufacturing. It strongly promotes the development of steel pipe industry in terms of variety, output and quality due to the development of oil in the early 19th century, the manufacture of ships, boilers and planes during two world wars, including the manufacture of thermal power boilers after the second world war, the development of the chemical industry and the drilling, transportation of petrolatum and natural gas.

1. Adopt power supply with vertical external characteristics and positive polarity (welding wire connected to negative electrode) for DC (Direct Current).

2. It is generally suitable for welding thin plates under 6mm, featuring beautiful weld formation and small welding deformation.

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

4. The length of tungsten electrode protruding from the gas nozzle is preferably 4-5~6mm, which is 2-3 mm in places with poor shielding such as fillet welding and 5-6 mm in places with deep groove, and the distance from nozzle to working area is generally not more than 5mm.

5. In order to prevent the occurrence of welding blowholes, any rust, oil stain, etc. on the welding parts must be cleaned up.

6. The length of welding arc is preferably 2~4mm when welding ordinary steel, and 1~3 mm when welding stainless steel. If it is too long, the protection effect won't turn out well.

7. When priming the butt, the back side of the underlay needs to be shielded by gas to prevent oxidation.

8. In order to protect the welding pool well with argon and facilitate the welding operation, the tungsten electrode centerline and the workpiece at the welding position shall generally maintain an angle of 80 ~ 85 degrees, and the included angle between the filler wire and the workpiece surface shall be as small as possible, generally about 0 degrees.

9. Wind prevention and ventilation. Where there is wind, make sure to equip with blocking net, and take appropriate ventilation measures indoors.