What is the proper and recommended weld preparation for true tangential nozzle on pressure vessel.
Where can something about this thematic be found.
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$\begingroup$ Could you provide a sketch, where the diameter and thickness of the nozzle is shown with respect to the cylinder diameter and thickness. Or the eccentric dimension of the nozzle to the vessel center? I have made a 3D modeling program that manages these types of nozzles for my company, maybe I could assist but I need more intel. $\endgroup$– Mech_EngineerJun 23, 2017 at 8:44
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3 Answers
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The welding codes and standards will apply relevant to your country / location / insurance specifications no matter what angle the nozzle is welded at.
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$\begingroup$ True, but this is not always practical, you might need a variation in the preparation to create a clean weld. $\endgroup$ Jun 23, 2017 at 8:47
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$\begingroup$ Thank You for Your answer. Yes relevant codes define it but, as Mr. Mech_Engineer say in practice it is hard to ensure good weld quality in this type of nozzle on vessels. $\endgroup$– Sysrq147Jun 23, 2017 at 15:18
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$\begingroup$ You have no choice but to make sure that the weld is of good quality - there are too many examples of the consequences of failure... $\endgroup$ Jun 23, 2017 at 15:55
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$\begingroup$ Yes, without any doubt ! That is why I am trying to find proper way or example of doing quality weld preparation to ensure (with other measures) quality weld. Thank You for Your answers. $\endgroup$– Sysrq147Jun 23, 2017 at 17:17
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All code considerations aside, at high pressures the stress distributions in this nozzle configuration demand significant reinforcement and superior welding. The vessel begins to act less like a solid shell and more like a loosely held together curved beam. It is not uncommon for the reinforcement pad to extend out so far that the nozzle + pad take up half of the circumference of the shell.
Anytime a nozzle places this much of a gouge in the shell wall, it should have higher than normal QA/QC reviews and extensive engineering review to confirm compliance with codes and satisfactory factors of safety.
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With a few assumptions : Dimensions indicate pressure below where serious codes like ( USA) ASME section 8, div, 1 would apply. Although "lethal" materials would change that. You could still look at any available code to see what those requirements are. In particular weld reinforcement/ thickness. No code = no NDE , but assuming steel, It wouldn't be too expensive to do some magnetic particle testing ( MT). But , for example, if it will contain gasoline in a crowded area, you should get serious.
answered Sep 21, 2017 at 19:50
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$\begingroup$ I looked at ASME on line ; My interpretation ( for USA ), if it contains primarily water at < 300 psi and < 210F , do what you want. If it contains anything else and the pressure < 15 psi , do what you want . But I am sure is only if it is not lethal per code definition . Of course you must follow code if you do not meet these exceptions. $\endgroup$ Sep 21, 2017 at 21:47