Heat Treatment and Stress Relieving
In-plant stress relieving, so a bend does not leave the building to be heat treated.
Why stress relieving is done here and not somewhere else
American Pipe Bending has in-plant stress relieving equipment, and lists heat treatment and stress relieve among the processes it provides against a customer bending specification.
Bending puts residual stress into a part. On the outside of the arc the metal has been stretched, on the inside it has been compressed, and both are locked in when the pipe cools. Depending on the material, the wall and the service, that stress either does not matter or it very much does. Where the specification calls for it to be relieved, the part goes into a controlled heat cycle that lets the stress out without changing anything else.
Having that on the same floor removes a transport leg and a handoff. On a heavy section the transport leg alone can be several days and a crane at each end, so this is a schedule item rather than a convenience.
Request a quoteHeat treatment around an induction bend
Induction bending already involves a heat cycle: a narrow band is heated, the bend forms inside it, and controlled cooling by air or water spray follows the coil. That cooling step is chosen for the material and it is the first place the final properties are set.
What is needed after that depends on the material and the code. Some work is complete as bent. Some needs a stress relief. Some alloys need a full solution anneal, and duplex and titanium each have their own reasons. Settle it at quote stage: the cycle, the hold time and the verification method all change the price and the schedule.
Verification is usually Brinell hardness, which is on the list of tests we can provide, and it is how a reviewer checks that the cycle did what the procedure said it would.
Post weld heat treatment
PWHT is the same idea applied after welding rather than after bending, and on a code job it is often mandatory rather than optional. Where a bend from this shop is part of a welded assembly, the heat treatment requirement belongs in the enquiry with everything else.
Send the procedure, the code paragraph it comes from and the verification the specification requires, and we will confirm in writing what can be done here and what is subcontracted, before the job starts rather than after.
What to send, and what it costs to leave out
Five numbers describe a bend: outside diameter, wall thickness, centerline radius, bend angle and the tangent length on each end. Add the material, the quantity and the code and the job can be priced. The quote form takes a drawing up to 25 MB in PDF, DWG, DXF, JPG or PNG, and a photograph of a marked-up print is fine.
The things most often left out are the ones that change the price most. Documentation is the first: material test reports, non-destructive testing and heat treatment all have to be priced and scheduled from the start, and retrofitting a package onto a finished bend is slow and sometimes impossible. The delivery date is the second, because it decides whether the job is possible rather than what it costs.
The third is the acceptance criteria. Wall thinning on the outside of the arc and ovality through it are the two numbers a reviewer checks first. Tell us the limits and we will confirm the tightest radius that holds them before anything is cut. Finding the boundary at quote stage costs nothing; finding it at first article costs a length of pipe and a week.
Where a drawing calls out a bend that cannot be made as dimensioned, you will hear about it at quote stage rather than at delivery. That happens more often than it should, usually because an isometric was drawn without a bend schedule and the radius was never checked against the wall. Working back from an isometric to the five numbers each bend needs is routine here, and it normally catches at least one dimension that does not close.
Testing we can provide
Per your bending specification, not ours. Tell us the code and the acceptance criteria and we will say what runs here and what is subcontracted.
Other ways we bend
Wall thickness, radius, material and schedule decide the method. If you are not sure which fits, send the drawing and we will tell you.
Heat Induction Bending
Cojafex induction bending up through 42″ O.D. and 4″ wall, in any radius, angle or plane.
Coiling
Helical, spiral wound and serpentine coils, cold, up through 10″ pipe.
Cold Bending
Rotary draw bending on fourteen machines, with mandrels and wiper shoes where the radius needs them.
Mandrel Bending
Ball mandrels and wiper shoes for tight radii and thin walls that would otherwise collapse.
Large Diameter Pipe Bending
The work most shops turn away: up to 42 inch outside diameter and 4 inch wall.
Stainless and Alloy Bending
Stainless, duplex, Hastelloy, titanium and nickel alloys, bent without wrecking the metallurgy.
Have a drawing? Send it over.
Send a drawing or a sketch and our team will get back to you with a quote.