CliffordK

There should be machine shops that could anneal the bars, bend them, and repeat the heat treat.

They should also be able to give the exact metal composition, and alloy.

I can't say if any would actually want to do it.

One may also be able to do the annealing and heat treating in a ceramic kiln as bars aren't super large.

oldbobcat

The reply from Velo-Orange:

CliffordK

Interesting.

Here is a video of bar forming from another company.

oldbobcat

I would never hesitate to buy a handlebar made by these folks. I also wouldn't try to bend it.

kraftwerk 

Annealing is possible at home.. I have done it for some 'non-crucial' , ie.NOT handle bars, bits of aluminum.
First: 'blacken' the surface with candle-smoke, then you evenly heat the surface and burn off the soot...
like everything: it's all on utube to varying degrees of accuracy.
Remember: a little information could be dangerous...

jccaclimber

Several years ago I was discussing the heat treating of aluminum with an extruder who was making a custom extrusion for me. One of their past products was the extrusion for a bicycle handlebar maker. The name isn’t mine to share, but you’ve probably heard of them. The extruder would extrude the tube and give them the appropriate quench out of the extruder, but not do any artificial aging. This left it at T4 condition. The bar manufacturer would then bend them, and ship them out. At some point they started having cracking issues, and it turned out that the only difference was the handlebar manufacturer letting their unbent tubes sit around for an extra week. This is because aluminum will age harden at room temperature, it just takes longer than aging it in an oven.

Unfortunately in my case, my material was very thick and had not achieved T4 correctly (quench too slow), so no amount of aging was ever going to bring it to T6. I had to have it annealed, then returned to T6. Doing this properly, if you haven’t done it before, is not as easy as doing it on steel. Something this like a handlebar will be much easier than something thick, but you need to get it to the right temperature range, not go too much hotter as that would melt it, then hold it there a while. Later on you will want to reheat and quench it back to T4 if the extruder did that.

Or you could accept that while many have gotten away with it, this is actually a somewhat delicate process on an already used up safety critical component that isn’t all that expensive to just replace in the grand schemes of things.

downtube42

I'm not a metallurgist, but I used to work for one. He was also an alcoholic, and most of the work orders were written when he was lit, but that's another story.

Heat treating is a pretty generic term, meaning anything from simply cooling the material at an intentional rate after formation, to stress relieving by heating to a set temperature, to heating material in a liquid or gas that chemically penetrates from the outside in. The latter is commonly called case hardening, and that's often what people think of as 'heat treating'. But in reality all these processes are heat treating, and subtle time and temperature differences can make significant impact on material characteristics.

'Case hardening' generally causes material to be harder on the surface, but more brittle. Again generally speaking, bending case hardened material is a bad idea; microscopic cracks are likely.

But you can also increase brittleness by cooling too quickly. Or you can soften material by heating too high and cooling slowly. There are a lot of ways to screw up steel; even more for aluminum.

I expect there was a metallurgist involved in designing process by which the VO bars were made. Then that metallurgist went on to other projects, and the handlebar factory just follows the proscribed processes without anyone really understanding what's going on. And that's fine, up to the point when some smart guy says 'no, we don't heat treat our bars' without knowing anything about anything.

I effed up my share of parts, including aluminum, by deviating just a bit from the work order. Something can look great with the naked eye, then you look with a microscope and lo and behold you just scrapped someone's parts. There is no way in heck I'd cold set or "anneal" using some rule of thumb, aluminum handlebars, without advice from a real live metallurgist with knowledge of the material and how it was previously treated.

In the world of low paying dangerous unhealthy jobs, heat treat technician is just a notch above chrome plater, and chrome plater is the armpit of ****** jobs.