can you quench aluminum

[BrokenBiker]

pretty sure the answer will be no but i have no compressed air available at the moment, compressor is in bits awaiting a new valve

i know its not advisable with steel.

trying to make progress on something that involves welding 2 bits together enough to get a flat spot where the joint is, to mark out for a 96mm hole, but its 1/4" ally, im having to run it flat out at 200 amps with a bevel and a tickle of preheat which to be fair is going fine for what it needs to do but the cooling period is a lot longer than im used to with steel and want to crack on as much as possible while ive got the time. the one i welded out fully, that isnt havign a hole, is still untouchable 30 mins later. doesnt help that is baking hot in the shed at the moment either.

these parts will end up taking moderate forces that will try and bend the welds out so dont want to do anything that is going to weaken it.

pics of my iffy welds for attention

not perfect but getting better, and getting a bit mroe used to the pedal now. this will be fully welded, flattened off and then have some 5/16 square welded around 3 of the edges.

this one hasnt had any bevel as its having a 96mm hole through it, the weld was just to get a centre mark in and hold the piece together while cutting. once the hole is mostly cut ill be sticking it to a bit of 4"x1/8" tube so will get its strength there hopefully. a heavy tack probably would have been fine but here we are. this is also my first go at something thats actually going to be used in aluminum, and my first attempt at anything over 3mm thick.

 

[Erie Fred]

"Aluminum".....there are many flavors.
Be more specific, and you should be able to find more than
you need to answer your question.

Age hardening et all.

 

[BrokenBiker]

"Aluminum".....there are many flavors.
Be more specific, and you should be able to find more than
you need to answer your question.

Age hardening et all.

Sorry. Should have been specific.

In this case it's 1/4" 6082 being welded to itself with 4043 filler

 

[hotponyshoes]

Quench a test price.
If it doesn't crack see if the amount of distortion is acceptable.

If you are already running the machine at maximium at 200a then the heat in the workpiece will actually be helping you.
Some of those reflective sleeves and gloves would be my choice if I couldn't get more than 200a to chuck at it.

 

[addjunkie]

Ive herd of it been quenched in oil, but not sure why, probably a slower more controlled quench.

 

[Kram]

Theres little point in welding where the weld will be. Will you be boring it out in lathe/mill or using a holesaw?

After welding, place it on a large lump of cold alu and the heat will be sucked out at an acceptable rate. Once its 100c I would consider that ok to quench in water, shouldnt have any detrimental effect.

If it needs a holesaw pilot I would either use a lump of wood, over the top and glued/clamped as a guide, or weld either side of the hole, and the centre 10mm so that a normal pilot drill can be used (swap it for a plain hss bit for the holesaw)

If you undersize the hole, then you'll be able to weld the ID join line before final boring to size, that will hide the fact its been welded.

 

[BrokenBiker]

Quench a test price.
If it doesn't crack see if the amount of distortion is acceptable.

If you are already running the machine at maximium at 200a then the heat in the workpiece will actually be helping you.
Some of those reflective sleeves and gloves would be my choice if I couldn't get more than 200a to chuck at it.

while i was welding the heat was very helpful, but the part in question doesnt need any furhter welding til the hole is in it. i ended up letting it cool til i could handle it.

i will try and quench some off cuts saturday when i get back at it...shed time cut short once again and im back in work tomorrow for a whole day (the cheek of it)

Theres little point in welding where the weld will be. Will you be boring it out in lathe/mill or using a holesaw?

After welding, place it on a large lump of cold alu and the heat will be sucked out at an acceptable rate. Once its 100c I would consider that ok to quench in water, shouldnt have any detrimental effect.

If it needs a holesaw pilot I would either use a lump of wood, over the top and glued/clamped as a guide, or weld either side of the hole, and the centre 10mm so that a normal pilot drill can be used (swap it for a plain hss bit for the holesaw)

If you undersize the hole, then you'll be able to weld the ID join line before final boring to size, that will hide the fact its been welded.

the weld was there to hold the 2 pieces together, so i could flat the weld back and accurately mark out the hole and then cut. the tacks on the ends were purposely weak so i could easily pop them apart after cutting the hole for prep before final welding to a short length of 4" tube. no real need for the 30mm long weld in the middle other than im still practicing so every bead helps.

i dont have a large block to use a heat sink unfortunately. had i not been waiting for a new valve for the compressor id just hit it with some air to cool it.

 

[Erie Fred]

Sorry. Should have been specific.

In this case it's 1/4" 6082 being welded to itself with 4043 filler

Understanding 6082 Aluminum: Heat Treatment, Strength

Explore 6082 aluminum’s properties, heat treatment, strength, and applications. Learn how it compares to other alloys and why it's ideal for industries.

machining-quote.com

 

[hotponyshoes]

Not relevant to the original question but trying to holesaw through aluminium weld is hard work as it is gummy.
Leave it a week and it will cut a lot better!

 

[BrokenBiker]

Not relevant to the original question but trying to holesaw through aluminium weld is hard work as it is gummy.
Leave it a week and it will cut a lot better!

thanks for the tip, will bear that in mind.

i did have the foresight to not weld where i needed to cut though but still a good tip, thanks

 

[Keith 66]

Its worth bearing in mind that quenching aluminium at the right temperature anneals it very effectively, Paint a stripe of soft soap on it & heat with torch when the soap goes brown quench it, It is then annealed, As welding isnt a full heat of the part any quenching & subsequent annealing will be very localized & may lead to stress cracking

 

[MattF]

Ive herd of it been quenched in oil, but not sure why, probably a slower more controlled quench.

I was led to believe that the reason for using oil is for a consistent quench, as it's not boiling off as water would, so the whole surface is cooled evenly.

 

[Popcorn]

Waters out coz of Hydrogen Embrittlement, it's ok if your just padding beads practicing.
But not for anything you want to stay together.....

 

[Erie Fred]

I was led to believe that the reason for using oil is for a consistent quench, as it's not boiling off as water would, so the whole surface is cooled evenly.

A slower quench.
Water is just as consistent, especially if kept agitated.

 

[BrokenBiker]

Waters out coz of Hydrogen Embrittlement, it's ok if your just padding beads practicing.
But not for anything you want to stay together.....

Now that's something I didn't know.

Quenching is out then

 

[Screwdriver]

I would clamp a heat sink as close as possible to the weld so that the entire piece doesn't heat up in the first place. Assuming you're clamping it down to a steel worktop/welding table, I'd also clamp some large flat lumps of steel/ally/copper next to the weld and if you have a selection (or quench the heatsinks) you should be able to move a bit more quickly.

What I don't know (and I am sure someone will put me right) is how that might effect the quality of the weld. I assume it will be fine because you only want to superheat the bit that needs to stick...

 

[hotponyshoes]

I would clamp a heat sink as close as possible to the weld so that the entire piece doesn't heat up in the first place. Assuming you're clamping it down to a steel worktop/welding table, I'd also clamp some large flat lumps of steel/ally/copper next to the weld and if you have a selection (or quench the heatsinks) you should be able to move a bit more quickly.

What I don't know (and I am sure someone will put me right) is how that might effect the quality of the weld. I assume it will be fine because you only want to superheat the bit that needs to stick...

It sounds to me like the op only has a 200a machine. That's pushing it for 1/4" Thick aluminium.
I wouldn't want to be sucking any heat out of the material. In fact I'd probably be preheating it if it was an important job

 

[BrokenBiker]

I would clamp a heat sink as close as possible to the weld so that the entire piece doesn't heat up in the first place. Assuming you're clamping it down to a steel worktop/welding table, I'd also clamp some large flat lumps of steel/ally/copper next to the weld and if you have a selection (or quench the heatsinks) you should be able to move a bit more quickly.

What I don't know (and I am sure someone will put me right) is how that might effect the quality of the weld. I assume it will be fine because you only want to superheat the bit that needs to stick...

A heat sink would dramatically reduce the penetration for me. I'm underpowered and already having to bevel and preheat just to get halfway through it with the weld.

The hole is in the pieces now though, and they have all been tacked up with a spacer between.

Added bonus, compressor is up and running again now so have compressed air to aid cooling when needed

 

[hotponyshoes]

What I don't know (and I am sure someone will put me right) is how that might effect the quality of the weld. I assume it will be fine because you only want to superheat the bit that needs to stick...

I'm not really sure what the job is, but, in general, moving quickly is better with aluminium as you'll get a smaller heat zone.
You'll also lessen the risk of the hydrogen embrittlement mentioned previously although I wouldn't be particularly concerned with that with 6082.
Basically, the less time the metal stays molten the better. Aluminium soaks up heat quickly so if you can hit it with a large amount of power quickly, melt it, add filler, move along, it's better than waving the torch around for ages trying to heat it up as the heat gets drawn away from the weld zone by the rest of the material/the workbench/the clamps/any extra heatsinks/etc.

If you had a 300a machine and some 3.2 filler you could probably back the weld gap up with copper, clamp thick heatsinks either side and blast along it and after a foot of weld you would probably be able to pick the piece up from the starting end with a decent pair of gloves.
250-250a would be my choice for that (on a steel bench) as I haven't got 300a available.
Then I'd do something else for 20mins while it cools down.