Precautions for welding stainless steel pipes The development of steel pipe technology began 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 natural gas have all strongly promoted the development of the steel industry in terms of variety, output, and quality. 1. Use a power supply with vertical external characteristics, and use positive polarity when direct current (welding wire connected to the negative pole). 2. Generally suitable for welding thin steel pipes below 6mm, with beautiful weld formation and small welding deformation. 3. The protective gas is argon with a purity of 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.
4. The length of the tungsten electrode protruding from the gas nozzle is preferably 4~5mm, 2~3mm in places with poor masking such as fillet welding, 5~6mm in places with deep grooves, and the distance from the nozzle to the workpiece is generally not more than 5mm.
5. To prevent the appearance of welding pores, if there is rust, oil stains, etc. on the welding part, it must be cleaned.
6. The length of the welding arc is preferably 2~4mm when welding ordinary steel, and ~3mm when welding stainless steel. If it is too long, the protection effect will be poor.
7. When butt-bonding, in order to prevent the back of the bottom weld from being oxidized, the back also needs to be protected by gas.
8. In order to make the argon gas protect the welding pool well and facilitate the welding operation, the center line of the tungsten electrode and the workpiece at the welding point should generally maintain an angle of 80~85°, and the angle between the filler wire and the surface of the workpiece should be as small as possible, generally around 0°.
9. Wind protection and ventilation. In windy places, be sure to use a screen to block the wind, and in indoor areas, appropriate ventilation measures should be taken.
