Started with the rise of the bicycle manufacturing industry. The development of oil in the early 19th century, the manufacture of ships, boilers and aircraft during the two world wars, the manufacture of thermal power boilers after the Second World War, the development of the chemical industry, and the drilling and transportation of oil and gas, etc. The development of the large diameter welded steel pipe industry in terms of variety, output and quality.
1. The power supply adopts the vertical external characteristic, and the positive polarity is used in the direct current (the welding wire is connected to the negative electrode).
2. It is generally suitable for the welding of thin plates of 6mm or less, and has the characteristics of beautiful weld bead formation and small welding deformation.
3. In order to prevent the occurrence of welding vents, the welding parts must be cleaned such as rust and oil.
4. Welding arc length, when welding ordinary steel, 2~4mm is better, while welding stainless steel is better than ~3Mm. If it is too long, the protection effect is not good.
5. When the bottom of the butt weld is prevented from being oxidized, the back side also needs to be protected by gas.
6. 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 workpiece surface should be as small as possible. Usually about 0 °.
7. Wind and ventilation. In windy places, take measures to block the net, and indoors should take appropriate ventilation measures.
8. The shielding gas is argon with a purity of 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.
9. The length of the tungsten electrode protruding from the gas nozzle is preferably 4~5mm. In the place where the shielding property such as fillet welding is 2~3Mm, the depth of the groove is 5~6mm, and the distance from the nozzle to the working is generally not More than 5mm.