The impact of welding on small-diameter thin-walled nozzles
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For small-diameter nozzles, whose wall thickness is often less than 6 mm, is their welded structure suitable for a fully penetrated design? Furthermore, what is the mechanism by which welding thermal stress affects pipes and containers?
What is the small diameter? A pipe thickness of 6mm with a diameter of 200 is no longer considered a thin-walled pipe.
A 6mm thick pipe shouldn’t be considered a thin pipe, right? Whether full penetration is required is determined based on your design specifications. Under normal circumstances, the joints between the take over parts need to be fully welded through. For the welding between the connecting pipes here, the thinnest thickness is around 3 mm; for plug-in type pipes, the thinnest thickness is 2 mm, with a pipe diameter of 10. As for the connections between the plates, the thinnest thickness here is 1.5 mm.
4 mm; the head wall thickness is 16 mm, which is less than 6 mm – in fact, it’s even less than half of the wall thickness. I’m not sure whether full penetration welding is appropriate in this case
I’m not familiar with welding; I checked some books, but they didn’t provide such detailed information. I’m quite concerned about the impact of the heat-affected zone resulting from full penetration welding on the strength of the pipes
The wall thickness is only 16 mm, so there’s no problem.
No problem; whether it’s an internal weld or an external weld, it’s still a fillet weld, so welding isn’t an issue. The weld metal typically used is also of thin plate thickness.
Okay, now I can rest easy. Thank you.
The wall thickness of the connecting pipe generally refers to that of the equipment casing, and it should usually be no less than half of the casing’s thickness. It mainly depends on the type of welding joint chosen; the original poster can refer to relevant standards when making a decision. If the wall thickness of the connecting pipe is too thin, it is easy for the weld to burn through during welding.
I have similar concerns too...... Thanks for the reminder! !
For a head with a thickness of 16 mm, a fitting that is only 4 mm thick would not be used; firstly, the external loads acting on the fitting could cause the joint between the fitting and the shell to crack, and secondly, if the thickness difference between the fitting and the shell wall exceeds 2 times, local discontinuous stresses can become very high. Of course, there is also the issue of burn-through, but this problem isn’t that serious; it should be possible to control the input current for multi-pass welding as well