Problems welding thin wallthickness pipe
Problems welding thin wallthickness pipe
(OP)
Hi,
I am selecting the specification of a pipe system for cooling a nuclear experiment. The material you selected by the characteristics of Fluids is stainless steel A312 Gr 316L TP for various diameters.
Several colleagues with experience on the site, have warned me that buttwelding pipe with 'large' diameters (18 ", 10") with thin thickness (sch-10s) can cause technical problems, and many headaches.
I have to decide between lower costs of supply and erection, but possible technical problems when welding.
I would like to know what you think people with experience in welding.
thanks in advance
I am selecting the specification of a pipe system for cooling a nuclear experiment. The material you selected by the characteristics of Fluids is stainless steel A312 Gr 316L TP for various diameters.
Several colleagues with experience on the site, have warned me that buttwelding pipe with 'large' diameters (18 ", 10") with thin thickness (sch-10s) can cause technical problems, and many headaches.
I have to decide between lower costs of supply and erection, but possible technical problems when welding.
I would like to know what you think people with experience in welding.
thanks in advance





RE: Problems welding thin wallthickness pipe
Warpage will be an issue. I would suggest using the GTAW process and keep the interpass temperature less than 325 deg F. Watch your start and stops.
RE: Problems welding thin wallthickness pipe
RE: Problems welding thin wallthickness pipe
RE: Problems welding thin wallthickness pipe
We see a lot of people use sch40 in places where sch5 will meet the design just because they don't want to do the work.
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Plymouth Tube
RE: Problems welding thin wallthickness pipe
greetings
RE: Problems welding thin wallthickness pipe
If you are using ERW pipe, it can have ovality problems that become part of the "work" Ed Stainless mentions above. I for one am in the world he describes. Light schedule pipe creates more problems than it solves.
If this were to have been a highly exotic alloy grade, Duplex or Hastelloy for example, you'd have to use the lighter gage due to cost difference, obviously.
rmw
RE: Problems welding thin wallthickness pipe
You will need to be careful sourcing it.
For ease of welding the welds will need to be planished flush on both ID and OD.
For good corrosion resistance it will need to be fully furnace annealed.
And then they have to make it round again.
This is custom fabricated pipe.
If the aerospace guys can butt weld 4"x0.032" wall then you can weld this.
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Plymouth Tube
RE: Problems welding thin wallthickness pipe
One tiny leak will shut the plant down and some little old lady that lives 20 miles down the road will want to sue over radiation sickness.
RE: Problems welding thin wallthickness pipe
-possible no disponibilty of fittings, or high cost
-alignment & ovality problems
- we don't know if our assemblers can weld appropriately this pipes
anything else?
will see
RE: Problems welding thin wallthickness pipe
As long as you specify (and can tolerate) welded seam, the fittings and pipe are no problem to come by, though it appears that what suppliers send us are often sch40S fittings that were a little under-thickness: they have been back-prepped on the ID to take them back to sch10S thickness. Those need to be checked carefully before use or you may have problems with RT later.
Preparation for butt welding takes some time and some tooling, but the welding itself takes fewer passes. People that make thin-wall stainless vessels have it way harder. Find a competent weld shop and they'll do a great job for you.
It can look a little ugly if the deposition rates are too high- you do tend to get a bit of diametral shrinkage.
Make sure you don't use 3000# o-let fittings for branches and then expect the welder to completely fill the bevel. You will end up with a sausage, and for no reason. There are better alternatives available.
RE: Problems welding thin wallthickness pipe
What does it say about our people?? Some seem to glow at night!!
RE: Problems welding thin wallthickness pipe