Thin-walled stainless steel pipe welding forming technology

Thin-walled stainless steel pipes are prone to welding through, deformation, and rusting of welds during welding. The problem lies in the welding equipment, welding parameters, and operating details. Next, I will show you the welding forming technology of thin-walled stainless steel pipes.

1. Use the left welding method, and the welding torch moves forward at a uniform speed, keeping it from jumping up and down. The welding wire is added from the front edge of the molten pool along the weld and close to the weld. The amount of addition depends on the gap and speed. Try to add as little as possible to avoid the formation of concave welds in flat welding and convex welds in overhead welding. The principle is to form the weld once.

2. The end of the welding wire is always within the argon protection range to prevent the red-hot end from oxidizing. The welding wire should not be extended into the molten pool to disrupt the argon flow. The welding wire must be thin, with a diameter of 0.8 to 2.5 mm. The welding current of thin-walled stainless steel pipes should not be too large, as small as it can dissolve the welding wire, generally between 40 and 100A. Argon gas flow rate 8L/min, torch nozzle aperture 8mm, nozzle and workpiece distance 5-10mm.

3. The faster the welding speed, the better, the smaller the deformation and the more beautiful the weld. Because even with inert gas protection, stainless steel welded steel pipes are inevitably in contact with oxygen in the air. The longer the edge of the heated steel pipe billet is exposed to the air, the deeper the layer of non-metallic oxides will be produced, causing intergranular corrosion, thereby destroying the continuity of the weld structure and forming a clear brittle interface.

In addition, a large amount of alloying elements such as manganese and carbon are burned out and evaporated during the welding process of stainless steel precision steel pipes, which reduces the mechanical properties of the weld. It can be concluded that the slower the welding speed, the easier it is for the weld to rust. By speeding up the welding speed, the weld quickly leaves the heating zone, and quickly adds water to cool it, the purpose of refining the weld grains can be achieved.

4. When striking the arc, the gas should be supplied 3-5s in advance. Before extinguishing the arc, the travel speed should be increased first, and then the arc should be extinguished to eliminate the arc pit. Use imported pickling paste for post-weld cleaning. Use a wire brush to remove the oxide scale 20 minutes after applying it, and rinse with clean water. For thin-walled stainless steel pipes with low requirements, you can also use a wire brush directly, for brushing and rinsing.

5. The welding machine is also particular. Generally, an inverter AC/DC welding machine is selected, and the current is relatively stable. Non-melting electrode argon arc welding arc can be used, which has stable combustion, concentrated heat, high arc column temperature, high welding production efficiency, narrow heat-affected zone, and small stress, deformation, and crack tendency of the welded weldment. It is suitable for welding stainless steel thin-walled steel pipes, good ports can be obtained, and the mechanical properties can be guaranteed. However, the current carrying capacity of the tungsten electrode is limited, and the current cannot be too large, but the quality can be guaranteed, and there is no need to open a groove when welding thin steel pipes, which is very convenient.

The above is the content of the welding forming technology of thin-walled stainless steel pipes. When welding thin-walled steel pipes, the left welding method should be adopted, the end of the welding wire should always be within the argon protection range, the welding speed should be accelerated, the current should not be too large, the weld should be cooled with water, the gas should be supplied 3 to 5 seconds in advance when striking the arc, and an inverter AC/DC welding machine with relatively stable current should be selected. In this way, the thin-walled stainless steel pipe will not be deformed during the welding process.