How should plasma welding evaluation be conducted?
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The company has just purchased a new plasma automatic welding machine, and now a plasma welding assessment is required. However, no one in the company has any experience with plasma welding, so we really don’t know where to start :( (:' (:' I would like to ask those who are more experienced – how should this plasma welding assessment be carried out?~~~~
Let’s follow NB/T 47014-2011: lol
Plasma arc welding is most suitable for welding joints with I-groove welds (without grooving); generally, it can be used to weld stainless steel up to 10 mm thick (with a safe limit of 8 mm). Due to the narrow process parameter window for plasma, it is recommended to conduct a weld evaluation for each thickness.
What material is the weld evaluation for? Generally, as mentioned above, it involves welding plates around 8 mm thick with an I-shaped groove. The welding machine can be used for plasma welding as the base layer and TIG welding for the finishing layer
It involves using plasma welding for the root pass without wire feeding, followed by TIG welding for the cover pass; I’m not sure whether this welding procedure can be applied to pressure vessels
Using P+T for the longitudinal seams of the cylinder is fine; a longitudinal seam welder offers extremely high efficiency； P+T welding for the cylinder ring seam is not recommended, as it is very difficult to control the cylinder’s roundness ； Don’t try welding the ring joint between the cylinder and the head – it’s a futile effort with no positive results.
For plasma welding evaluation specimens, S30408 is recommended with a plate thickness of 8 mm and a Type I groove; it is crucial to determine the appropriate welding parameters (current, voltage, and welding speed). The specific procedures should follow NB/T 47014-2011.
Welding evaluation is, of course, based on the standards applicable in your area; you select the appropriate material grade and thickness for welding. . It’s not difficult in itself; it just lacks an entry point. . .