Cold Bending
Rotary draw bending on 14 machines, with mandrels, wiper shoes and booster equipment where the radius needs them.
Fourteen machines and decades of tooling
American Pipe Bending bends cold, pneumatically and hydraulically, including compound and out-of-plane bends, around machined case-hardened bend dies. Special tooling covers ball mandrels, wiper shoes and booster equipment.
The shop runs 14 cold bending machines. That number is the reason we can hold a delivery date on a production run: a single machine tied up on one part number stops everything behind it, and fourteen do not.
Our staff brings decades of experience to precision bends across virtually all materials, from carbon and stainless steels to exotic alloys, brass, aluminum and titanium. Tooling has been acquired and upgraded over that period, which is what keeps the shop able to quote a size somebody else has retired the dies for.
Request a quoteWhat the tooling is for
Cold bending works by pulling the section around a die. Left to itself the wall on the outside of the arc stretches and thins, the wall on the inside compresses and wrinkles, and the round section goes oval. The tooling exists to stop each of those.
A ball mandrel goes inside the pipe and supports the wall through the tangent point, which is what allows a tight radius on a thin wall without the section collapsing. A wiper shoe sits behind the bend die and irons out the wrinkle before it forms on the inside of the arc. Booster equipment pushes from behind so the draw is not doing all the work, which reduces thinning on the outside.
Which of these a job needs comes from the ratio of wall to diameter and the radius you are asking for, not from preference. It is worked out at quote stage, because it changes both the price and whether the bend is possible.
Where cold bending is the right answer
Cold bending suits smaller diameters, tighter radii and repeat production. There is no heat cycle, so there is nothing to do to the metallurgy afterwards and nothing to certify about it. Setup on a machine already tooled for the size is quick, so a hundred identical bends cost far less each than one.
It stops being the right answer when the wall gets heavy relative to the diameter, or the radius gets tight relative to both. At that point the section will not move without damage whatever tooling is behind it, and the job belongs on the induction bender instead. Send the numbers and we will tell you which side of the line you are on.
Off the floor
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.
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.
Custom Pipe Fabrication
Cutting, end prep and fabrication around the bend, so one purchase order covers the package.
Have a drawing? Send it over.
Send a drawing or a sketch and our team will get back to you with a quote.