Welding issues in pipelines
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Our engineering team is currently working on the pipes; I went to the site today to observe the welding process. The installation team carries out welding in the following manner: first, the two ends are spot-welded together (with a gap of 3–5 mm left), then a backing weld is done using spot welding rods inside, after which a cut is made on the surface, and finally two layers are welded on top of that cut (both layers are welded using electric welding rods). The pressure in the pipeline is not high, around 0.3–0.5 MPa, but I have doubts about the quality of the welding, as there is a lot of slag and other debris left after welding with electric electrodes; if this debris isn’t cleaned away, proper welding cannot be achieved. I would like to ask my seniors whether it is appropriate to weld in this way ? ?
It can be welded directly using welding rods; it’s also possible to avoid using TIG welding for the root pass. The key is to ensure the quality of the weld and proper penetration. What are the welding process requirements specified by the construction party? Note that 3.2 grade welding rods must be used for the root pass – grade 4 rods cannot be used. Additionally, it’s necessary to maintain an appropriate gap between the weld edges. If needed, radiographic testing can be conducted as a spot check
One should first make the groove, then apply the root coat, and finally weld.
It can be welded directly using welding rods. . However, the weld quality must be ensured.
Maybe you misread it; they welded one side first and then cleaned the root on the other side. You mistook it for beveling.