There is an additional partition groove on the tube sheet; what is the best way to deal with this?
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Fixed tube sheet for a floating-head heat exchanger, with 4 tube passes; due to an issue during the supplementary drawing, there is an extra partition groove, 12 mm wide and 5 mm deep. Logically, this groove does not affect the calculations nor the installation. But now the pipe has been inserted and expanded, and there are two options if repairs are needed: place a plate of the same shape in the groove and weld it in place, then grind it smooth ； Grind after cladding the groove ； Since the tube has already been inserted, it will be very troublesome to operate. Moreover, it’s easy to see after both solutions are implemented that there is a concern that the added section might cause problems later on. Additionally, the distance between the pipes and the grooves is just a little over 2 mm, and welding on that area might affect the pipes that have been joined by expansion fitting. I don’t know how to handle this now. Should I tell the customer? What if they disagree? Then the entire piping system will be ruined. Has anyone encountered this problem? Are these two solutions feasible?
This post was last edited by Goodbye de Time on 2015-11-14 at 18:14. The reason now is to fill this slot – why weld a partition in place? Since I’ve never dealt with this kind of problem before, I’m worried that filling it in will make things look even worse.
It is best to use the second method, welding the groove and then grinding it.
It’s better to use the second method: surfacing, locally relieving stress, and then grinding it flat!
Is the color difference significant? I’ve never seen the effectiveness of this treatment method before, and another concern is the pipes – they are joined only by expansion fitting, and they are also close to the welds. But logically, there should be remedies in case of tube expansion leaks; the person in charge only considered the impacts, without considering that this issue can be resolved Is it just that I lack experience – once the tube is inflated, can’t it be moved anymore? Anyway, there are two opinions in the factory right now: one group says to leave it as it is (out of concern that it might have an impact), while the other group wants to make corrections but is hesitant and can’t decide. I’m young too; I can’t just act recklessly without thinking.
What material are your heat exchange tubes made of, and why is expansion used instead of welding? If it is only a crimp joint, welding repairs will definitely affect the seal; the extent of that impact is unknown. After treatment, there will be a color difference; the original surface had a metal color due to processing, while the areas that were rewelded and subjected to heat treatment turn dark blue.
If it does not affect strength, it is recommended not to take any action; it neither affects functionality nor appearance, after all it is inside
The tubes are of SA-179 grade, and the type of tube end connection is determined by the customer; the issue lies in not knowing how significant the impact of weld repairs will be. It has to be left like this for now, so as not to damage it. .
First, conduct a strength calculation; when doing the calculation, this depth should not be included within the tube sheet. Secondly and finally, perform surfacing welding or patch welding with the same material; do not use plates for welding, as the original structure uses expansion jointing, and using plates for expansion joining can easily lead to delamination, affecting the quality of the surrounding expansion joints.
For ordinary carbon steel pipes, the tube sheet should also be made of carbon steel. It’s strange that the original poster didn’t simply use a strong welding method; why use a strong expansion joint? Strong expansion joints are generally used when the two materials constituting the heat exchange tubes and the tube sheet cannot be welded together. Cladding welding can be used for repair; pay attention to calculating the strength of the repaired area, and it is best not to include the thickness of the groove section.