Square Tubing Pressure Application

[goomba]

I am interested in using 1.25" x .120" wall square, seamless, 304 SS for a supply manifold on a system using heat transfer fluid. The reason is for ease of fabrication. Maximum temperature is 350°F, maximum pressure is 35 psig. I realize square tube is not intended for pressure and not sure if ease of manufacturing is worth the trouble of proving this is a viable use of this material. Any suggestions? Thanks!

 

[dhengr]

Goomba:
What ease of fabrication? With today’s software for design, detailing and layout, and the equipment available to cut, prep. and weld, doing that manifold round to round would be a piece of cake for any fabricator worth his salt. The square or rectangular tube will give you real analysis and design headaches when you start considering temp. and pressure.

 

[goomba]

Your comments are well taken. Round it is.

 

[moltenmetal]

Tough to find seamless hollow structural steel anyway- it may exist, but I've never seen any. All the hollow structural steel I've ever seen, round or rectangular, has been welded seam.

 

[EdStainless]

Not only are SS structurals welded, but hey are not welded and tested like pressure tube.
In a modern power plant everything outside of the boiler and HP steam lines is welded tube, even the HP feedwater heaters are all welded. But you won't find that quality in square.
(as a side note, welded square would be much better than seamless, the wall variations in seamless shapes is often huge, they exempt the corners from the wall tolerance)

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P.E. Metallurgy, Plymouth Tube