1. Left welding mode is adopted, and the welding gun moves at a constant speed without jumping up and down. The welding wire is added from the front of the weld pool along and near the weld seam, and the amount of addition depends on the gap and speed. Work as little as possible to avoid the formation of concave joints when flat welding and convex joints when overhead welding, and take one-step welding as the principle.

2, welding wire end is always within the scope of argon protection, so as to avoid red-hot end oxidation. The welding wire should not extend into the molten pool to disturb the argon flow; The welding wire diameter is 2.0 ~ 2.5 mm, the welding current is 40 ~ 100a, the argon flow rate is 8L/min, the welding gun nozzle diameter is 8mm, and the distance between the nozzle and the workpiece is 5 ~ 10 mm. ..

3, when arc extinguishing gas supply 3 ~ 5 s in advance. Before extinguishing the arc, the traveling speed should be increased, and then the arc should be extinguished to eliminate the arc pit. Imported pickling paste is used for post-welding cleaning. In Shenzhen Jinwei Brewery, all pickling pastes are provided by German Ziman Company. After 20 minutes, brush with stainless steel wire to remove scale, and rinse with clean water. For pipelines with low requirements, stainless steel wire brushes can also be directly used to wash while brushing.

4. Non-melting argon arc welding can also be used, which is suitable for welding thin-walled parts and can obtain good joints and ensure mechanical properties. However, the current carrying capacity of tungsten electrode is limited, and the current can't be too large, but the quality can definitely be guaranteed, and you are welding thin-walled pipe fittings, which is not as convenient as the groove.

Extended data:

1. Argon arc welding is suitable for welding oxidizable nonferrous metals and alloy steels (mainly aluminum, magnesium, titanium and their alloys and stainless steel); Suitable for single-sided welding and double-sided forming, such as backing weld and pipeline welding; TIG welding is also suitable for thin plate welding.

Secondly, argon arc welding backing process can obtain high quality welded joints. Application of argon arc welding backing welding technology in the welding of boiler water wall, superheater and economizer. The quality of the joint is excellent, and the weld grade detected by X-ray is above Grade II.

Third, the requirements

1, good quality: as long as the appropriate welding wire, welding process parameters and good gas protection are selected, the root can obtain good penetration, and the penetration is uniform and the surface is smooth and tidy. There are no defects such as flash, incomplete penetration, depression, etc. which are easy to occur in general covered electrode arc welding.

2. High efficiency: the first layer of pipeline welding, manual argon arc welding is continuous arc welding. Covered electrode arc welding is broken arc welding, and manual argon arc welding can improve the efficiency by 2~4 times. Because there is no need to clean slag and repair weld bead, the speed is increased faster.

In the second layer of arc welding cover, the smooth argon arc welding bottom layer is very beneficial to the arc welding cover, which can ensure good fusion between layers, especially in the welding of small diameter pipelines.

3, easy to master: manual arc welding root weld, must be experienced, high technical level welder. Using manual argon arc welding as backing, workers who are generally engaged in welding can basically master it after a short period of practice.

4. Small deformation: the heat affected zone is much smaller when argon arc welding is backing, so the deformation of the welded joint is small and the residual stress is also small.

References:

Baidu encyclopedia-argon arc welding

References:

Baidu encyclopedia-left welding method

References:

Baidu encyclopedia-thin-walled stainless steel tube