Questions about pressure vessel weld joints
Thread Content
Dear Haihao friends: I have a question regarding the selection of welding joint types when designing a container, and I would like to discuss it with everyone. Since Note 2 in Figure D.4 of Appendix D \"Welded Joint Structure\" in GB150.3-2011 states that \"the joints shown in the figure are generally used for nozzles with a wall thickness of ≥1/2 of the shell wall thickness\", is it necessary to meet this requirement when selecting nozzles? For example: the wall thickness of the container shell is 20 mm; the nozzles are inserted into the shell and welded there, and the nominal diameters of these nozzles include various specifications such as DN40 and DN80. Does this mean that steel pipes with a wall thickness of 10 mm or more should be chosen? On the one hand, this is rather wasteful; on the other hand, it is also difficult to obtain DN40 steel pipes with a wall thickness of over 10 mm. Answer: In the interpretation of standard GB150, under P211 in the section titled \"III. Graphic and Textual Explanations\", it is stated that: \"As long as the welding joint requirements specified in the design drawings are met and the welding process has been approved through appropriate evaluations, manufacturing units, including experienced design firms, may use welding joint structures that differ from those outlined in this appendix.\" I urge all experts to share their opinions.
As you said, it’s not that strict.
The welding structure of the joints specified in the drawings provided by the design institute is clearly outlined, so manufacturing according to those drawings should present no problems.
I think so too, but welding a 3mm thick pipe to a 20mm thick shell seems a bit odd to me.
We design the drawings ourselves; we’re not an engineering firm.
As long as the strength is sufficient and there is a certain margin, there’s nothing to worry about.
The design must have the appropriate qualification, specifically a qualification for pressure vessel design. One has to take responsibility.
At the root of the container, whether it is a pipe to be inserted into the container or not, it is necessary to follow the specifications as much as possible. In other locations, the wall thickness can be appropriately reduced considering cost factors. :lol
Follow the standard procedure; there’s too much local stress over there, and simple calculations can’t capture that
Try to choose ones designed for thick-walled pipes; those that are too thin seem unreliable.