Tapered Piping Manufacturer

[Guest102023]

I'm investigating the feasibility of fabricating tapered pipe out of Hastelloy C-276 or similar C alloy for a crude overhead line.

First I want to know if this is a crazy idea, and second I am seeking competent fabricators. Dimensions are 22" x 16" over a length of 16'. Wall thickness 0.250" or 0.375". Critical factors are sound welds without loss of corrosion resistance, and good geometric tolerances.

While we're at it, are there better filler metals than the matching C-276? I've come across several sources recommending Inconel 686.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[BUGGAR]

Try Valmont Tube. They fabricate multi-sided tapered steel utility poles.

 

[Guest102023]

Not at all what I'm looking for, but thanks for trying.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[EdStainless]

If you find a fabricator that will press form the pater into pipe they could do the taper.
(we don't do it anymore)
You might be better off doing the taper over 4' and leaving the rest straight.
You can use C22 or 686, but what really matters with these alloys is the annealing.
High temp and long times.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[MintJulep]

Seems like a relatively straight-forward rolling job.

http://www.bakertankhead.com/gallery.htm

http://www.hodgsoncustomrolling.com/services/plate-rolling/

http://www.halvorsenusa.com/steel-alloy-plate-fabrication/rolled-formed-and-welded-steel-cones/

 

[Guest102023]

EdS,

Thanks for the suggestion, I had not considered shortening the taper and using straight pipe for the rest. Obviously spreading the taper over 16' adds complexity. In either case I would expect the seam weld to be made automatically on a pipe seam welder.

I've never ventured beyond C-276 before, so I'd like to know more about the annealing required for C-22 and I-686. Seems these alloys are not as interchangeable as I had assumed. Have any useful links?



"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[moltenmetal]

At this size, the thing should be treated as if it were a vessel shell rather than a pipe section. It should be possible to do, for sure, either by roll forming or brake bending. The seam will be done by whatever welding method works- but most likely by GTAW and by hand- it's a thin shell, only 0.25" thick. It will be greatly cheaper if you shorten the taper to 4'.

I'll leave it to smarter folks than me to recommend the welding alloys.

 

[Guest102023]

It needs to have a fairly gradual taper for flow reasons.

Manual GTAW would probably be my last choice, for reasons of gross distortion.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[moltenmetal]

There are people out there who make pipe to order, and they may be able to use their automated seam welding equipment to do your tapered pipe, but the question is whether or not it's practical for one piece of a very unusual shape. Tricor in Ohio is one company worth trying- they specialize in Ti, Ta and high Ni alloys and do have automated seam welding equipment. But unless you go with some kind of post-weld forming, it's not going to be perfect irrespective of how you weld it.

 

[StoneCold]

Here is an idea for you.
Why not add a stiffening ring to each end of the tapered pipe to keep it round. Maybe 4-6 inches back from the welded joint so that you have some room to make the but weld to the other pipe sections.

Just a thought.

Regards
StoneCold

 

[EdStainless]

The third (or is it fourth) generation "C" alloys such as C22, 686, and 59 have much better metallurgical stability than the original C or C276.
They are very different from each other. So you need to know the environment to select the best one. I have never seen a case though where C276 out performs any of these alloys.


= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[Guest102023]

Thanks, EdS

I believe it is generally better availability and user familiarity that favours C-276.

D. C. Agarwal (who works for VDM) gives an excellent survey in 'Handbook of Advanced Materials'.

http://www.amazon.com/Handbook-Adva...r=8-1&keywords=Handbook+of+Advanced+Materials

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[moltenmetal]

Depends on the product form, that. In some product forms, you can't find C-276 for love nor money, but C-22 is relatively easily found. Never spec a particular alloy when a generic soup will do.

 

[Guest102023]

I view sourcing the material, especially fittings, as the biggest challenge.
How much flexibility (welding-wise) is there in mixing and matching these alloys?
What is the most compatible filler and do any require post-weld heat treatment of any kind?


"If you don't have time to do the job right the first time, when are you going to find time to repair it?"