bending 40 pipe

Try heating the area to be bent dull red, then letting it cool slowly, before bending. Works on the stuff they sell around here, anyway.

Heat? Send a flame down inside the pipe while you are bending. Red heat helps.

But isn't black (or galv) pipe hot rolled (and welded)? I mean, if it works, fine, but...

Certainly, bending it hot will help.

Tim

-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @

I thought so, but after much experimentation, I don't even bother to bend without annealing the bend area first. The steel suppliers can supply pipe ready to bend, but the "normal" black pipe needs a bit of softening in order to bend without kinking. I am posting this from Australia, and the stuff you purchase in your country may bend differently.

Wayne

And not real round either. ERS

I don't know where you got this, but black pipe is generally a high quality, fairly high strength pipe. A53 and SA106 are two standards for black pipe, and both have strict limits for ductility, yeild, tensile of the material, size, material composition, discontinuities, longitudinal joint, etc. Of course, you can get dud 'code' material, but generally any grade of black pipe will bend wuite well.

After dealing with this stuff for years, I'd say that black pipe is the bottom of the barrel crud. I was referring to the normal "black pipe" that would be used for gas pipe or sprinker installations in sizes from

A106 is a spec for SEAMLESS pipe, a very high grade pipe that would never be non critical applications. And even this grade allows for a wall thickness to be as much as -12.5% under size. Diameter in the 1/8" to 1-1/2" range can vary +.015" to -.031" This can show up as ovality so it can read .046" out of round and still be within spec. In my opinion, that rates as some pretty cruddy stuff compared to the A513 spec for tubes in the same size range. (A513 as welded mechanical tube is +/- .0035") DOM is +.005 -.000"

Regular black 'iron' A53 is a welded product whose primary purpose it to handle fluids up to 300 psi and have sufficient wall thickness to thread properly. Using it in fabrication is a nightmare. Bending is especially problematic: surface finish chews up bend dies; can't run a mandrel due to weld flash; can't clamp consistently due to variabilty in diameter; ductility is extremely low; ductility is extremely variable, both from piece to piece and within a piece.

If these specs are your idea of "high quality", I know several companies that would like to hire you to debug manufacturing processes in their plants.

e wrote:

I gotta disagree, Eric. I used black pipe as rollers to move my Index

Eric R Snow wrote:

we used to production cold bend 2" schedule 40 black pipe in production, about a 10-12" bend radius, into a "U" shape

the trick, whether you form it hot or cold, is to support the pipe at the sides to prevent it from kinking

In the electrical trade we regularly bend rigid galvanized conduit, (which shares spec.s with sched.40 pipe), to radii of 6x Dia. If your radius is less that might be your problem. Try an electricians conduit bender. If the problem is the metalurgy of your pipe, you might try using conduit for the application. Pragmatist

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