Bending Inconel Tubing for Radiant Superheater

[Fender]

I was given a piece of inconel tubing, 5/8" OD X .040 wall X 4' long. I am proposing to use it for a project that requires a 180º bend with a 3" radius. What I have read is that this stuff is not easy to bend (or weld), and should be annealed first, which requires heating it to 2000º F. I don't have any special tools other than a conduit bender, which is the wrong radius. What I am thinking of doing is filling it with lead or sand to prevent the tube from collapsing, and making a bending die of the correct diameter from some steel plate.
A few of questions:
1. I can achieve this temperature with a torch, but does it have to be held at that temp and cooled slowly to anneal it?
2. Any better ideas than filling with lead or sand and using the bending die?
3. Is this just going to be too hard to do without special equipment & skills?

Thanks,

[Al_Messer]

I've never tried it with Inconel, but Salt packed into a Copper tube and the ends plugged can be bent around a mandrel and the Salt dissolved afterwards in hot Water. Good luck and please let us know the outcome.

Al

[Fender]

I've received info that this stuff requires a mandrel bender for the bends I want to make. Either that or fill it with cerrobend.

[fourjc]

We bent tons of tubing using Cerrobend, the minimum rad should never be less than 1 1/2 times the diameter of the tube, using cerrobend will maintain 85% of the tube capacity. It's like lead but melts in hot water, the site below has info on the product. Hope this helps.

http://www.cedar--rapids.com/Industrial ... ending.PHP

[Fender]

Fourjc,
Thanks for the info on cerrobend. I see from your link that the density is .339 lb/sq.in., which is useful in figuring how much of the stuff I would need to fill the tube. I know how easy lead is to bend, what about cerrobend? My bends will have a radius of about 480% of tube diameter, so this shouldn't be a problem, unless the force required is too high.

One more question, I calculate that one pound of cerrobend will fill a little over a foot of this tubing. Does only the part that will actually be bent need to be filled? If so, I wouldn't need more than a pound of the stuff.

[hammermill]

in my bending experence only the part from the hook to the back of the shoe and a bit 3 inches beyond needs to be filled as its role is to prevent tube calapse

[Al_Messer]

How did the job turn out! Curious people want to know.

Al