Stainless steel tube
Stainless steel tube
(OP)
I want to use 25 mm and 15 mm OD stainless steel tubes as air release pipe in transformers.Inside transformer oil at 80C.Shall withstand vacuum and positive pressure max 1 bar.Quality wanted is rust proofness.At ends normal mild steel flanges will be welded to stainless steel tubes.
1) What grade and thickness of SS is most appropriate?
2) What type of welding /electrodes to be used ?or flanges also should be SS?I thought of ordinary steel to reduce overall cost.
1) What grade and thickness of SS is most appropriate?
2) What type of welding /electrodes to be used ?or flanges also should be SS?I thought of ordinary steel to reduce overall cost.





RE: Stainless steel tube
To withstand the positive pressure, a pipe of 26.67mm OD with a schedule 5S wall thickness (1.651mm) should suffice for that purpose and a 13.7mm OD with a schedule 10S wall thickness (1.651mm) for the smaller tube.
Sizes can be found at this link:-
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For the vacuum however its a bit different because depending how long the tube or pipes are they may fail by buckling, so we would need details of the length of tube and how both ends are supported.
Welding electrodes could be sought from this site however any good pipe/vessel workshop will know which to use.
Again here this site should give you the stainless grade for flanges and pipe etc however I would say Stainless 316L is a good choice for corrosion.
Having said all that wouldn't the breather pipes come under the design specifications of the transformer which is what you really should be working to?
desertfox
RE: Stainless steel tube
Pipe is supported closely may be 1-2 metres and normally vacuum will not be a problem.
Well breather pipe also can be of stainless steel.
RE: Stainless steel tube
welding the mild steel flanges to teh end of a ss pipe will negate any corrosion resistance in the area of the weld. What is the environment that requires SS? Would you also need a non magnetic material to reduce eddy currents? Forgive the last uninformend comment!
Mark Hutton
RE: Stainless steel tube
if it's not exposed to agressive atmosphere SS316l is a good solution.
welding SS to CS is not a problem but if you can avoid it then it will be better also you'll avoid any issue of galvanic corrosion .
S
Corrosion Prevention & Corrosion Control
RE: Stainless steel tube
Now I understand 316L is the best solution and flanges also to be SS.I plan to use without any painting.
Thank you all
RE: Stainless steel tube
While it is possible that there could be some corrosion the chances are very slim that there will be anything inside the unit that will hurt the 304.
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Plymouth Tube
RE: Stainless steel tube
Mark Hutton