First determine the thickness of the workpiece, and then adjust the welding current to determine the gas flow, whether the workpiece is clean in place, and whether the gap between the two workpieces is opaque during positioning.

When welding, make sure that the angle of the welding torch is about 85, and the Hei Bang is 3-5mm away from the workpiece. When welding, the Hei Bang should be shaped into a cone to avoid the arc drift, which will affect the appearance of the weld and make the workpiece fail to achieve good fusion degree. Moreover, when welding, the angle between the Hei Bang and the workpiece should reach a horizontal line, so as to achieve the best penetration effect of the workpiece.

Extended data

Argon arc welding technology

1. welding example: the material of economizer, evaporation section tube bundle, water wall and low-temperature superheater is 20 steel, and the material of high-temperature superheater tube is 12Cr 1MoV.

2. Pre-welding preparation: Before welding, the nozzle should be bevelled by 30, and the inside and outside of the pipe end should be polished within 15mm. The pipe butt clearance is 1~3mm. When the actual butt joint gap is too large, it is necessary to establish a transition layer on one side of the pipe groove first. Set up temporary shelter facilities and strictly control the wind speed in the welding workplace, because the wind speed exceeds a certain range, which is easy to produce blowholes.

3. operation: WST3 15 manual TIG welding machine, which is equipped with high-frequency arc ignition device and can be used. Arc extinguishing is different from covered electrode arc welding. If the arc extinguishing is too fast, it is easy to produce arc pit cracks. Therefore, when operating, lead the molten pool to the edge or thick base material, then gradually reduce the molten pool and slowly extinguish the arc, and finally turn off the shielding gas.

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