Heat treating.

[Zamble]

I rewelded a Galil receiver. I want to heat treat it in a kiln. But a concern that was brought up is that it will warp in the kiln.

Can precautions be taken to prevent it?
Suggestions?

I thought about heat treating the FCG pin holes, then putting it in an oven at 500 for an hour. Would this suffice?

[kcstott]

I wouldn't bother with it depending on how close your weld was to the lugs.

if you got that area hot, then the whole thing should be heat treated. that will require fixturing and blocking but still no guarantee it won't move.

if all you are trying to heat treat is the pin holes. I wouldn't be to concerned about it.

[Zamble]

I wanted to heat treat the pin holes and throw it in the oven to relieve any stress in the metal if I didn't end up putting it in the kiln.

The locking lugs and barrel threads were not cut when it was torched.

I just don't want it to hand grenade on me.

[God Bless America]

The FCG holes have nothing to do with grenading. If the locking lugs were not affected by the welding, then no grenades in your future.

Worst case scenario with soft FCG holes is that they wear prematurely, oversized and egg shaped. That's all.

Given the complex shape of your receiver, I would not try to heat-treat it at home, even with a kiln. It took me several tries to learn how to heat treat stamped AK receivers, and they are of uniform thickness.

[ar15barrels]

I rewelded a Galil receiver. I want to heat treat it in a kiln. But a concern that was brought up is that it will warp in the kiln.

Can precautions be taken to prevent it?
Suggestions?

I thought about heat treating the FCG pin holes, then putting it in an oven at 500 for an hour. Would this suffice?

A fixture can be made which is MUCH thicker and heavier than the receiver.
Then the receiver is clamped to the fixture and the whole setup is run through the heat treat cycle.

500 is not much of an tempering temperature, but is better than not tempering at all.
I typically temper at 700 to 800 after quenching.
Tempering temperature just depends on your hardness goal.

[Zamble]

I knew heat treating the pin holes only prevents the ovaling of the pin holes.

My concern about it grenading was based on when it was originally torch cut. How the heat from it might have affected the strength of the metal.

But it's good to know that won't be a concern.

[God Bless America]

Check headspace and bolt lug wear regularly. Headspace has to stretch a fair amount for a while before locking lugs fail.

If the heat did affect the lugs, they got soft, which results in gradual wear, which can be detected long before catastrophic failure.

[kalibeltfeeder]

The 500 for an hour is suggested to releive the stress after re-welding. It's not for tempering something hardened. It will only prevent stress cracks.


When your receiver was torched in between the threads and the locking lugs, (which it was) that is what compromised the trunnion area, that torch would've heated the entire trunnion area Up way past the annealing temperature making your lugs soft. That's why I don't like to mess with receivers that have been cut there. Furthermore when you re-welded it you again heated up the lug area way past the annealing temperature.

Your safest bet for peice of mind would be to test it with a Rockwell tester, see how hard it really is or isn't and make a decision from there.

I've seen your receiver in person Steve, it's very nicely welded back together, I don't think it's going to blow apart.

I would at a minimum do the FCG holes. And like I mentioned before you can use my kiln anytime, but I agree with the others a solid fixture is mandatory. As nice as you did on your reweld ID hate to see it warp.

[God Bless America]

The locking lugs and barrel threads were not cut when it was torched.

When your receiver was torched in between the threads and the locking lugs, (which it was) that is what compromised the trunnion area,...

Which one is it? If it was cut close to the lugs, then the whole receiver needs to be heat treated.

[kalibeltfeeder]

I hope I'm not speaking out of turn here zamble

But yeah I've seen it, it was cut in between the barrel threads and locking lugs. Right thru The 'trunnion' area..

[God Bless America]

I hope I'm not speaking out of turn here zamble

But yeah I've seen it, it was cut in between the barrel threads and locking lugs. Right thru The 'trunnion' area..

You might be saving him some grief.

[Dnele928]

Not sure what metal/alloy you have. If it's aluminum, you need to find the heat treat cycle that suits the alloy you have. Often, aluminum needs a rapid water quench after the heat treat cycle. THIS is when the distortion occurs.

Aluminum metallurgy is weird, heat treating is weirder.

If you want more precise heat treat info, post the metal/alloy type. Need to know that first.

[kalibeltfeeder]

Not sure what metal/alloy you have. If it's aluminum, you need to find the heat treat cycle that suits the alloy you have. Often, aluminum needs a rapid water quench after the heat treat cycle. THIS is when the distortion occurs.

Aluminum metallurgy is weird, heat treating is weirder.

If you want more precise heat treat info, post the metal/alloy type. Need to know that first.

anybody know what the izzys used for their Galils?
It isn't Al...

[kcstott]

anybody know what the izzys used for their Galils?
It isn't Al...

send it off to Turnbull and have it color case hardened that will look good and cost a fortune

[kcstott]

I don't like commenting on this stuff because there are so many variable.

How was the receiver cut? as in how hot did the guy with the torch get the lugs?

How was it welded? what process? what was the welders skill level? What filler material? was any attempt at pre and post heating done? did someone watch their inter pass temp?? Yeah that over kill but you never know

then what is the base material?

and whats it going to take to re heat treat it?

FYI stress relief temp is typically 1200˚f for most Chrome alloy materials. that also can anneal the material too. Not fully but it will be damn soft.
Thats if is a 4130-4140, 8620 base metal. We use to cook material A36 and cold rolled at 1200˚f for a few hours shut the oven off and work on it the next day. the material was not dead soft but it machined so much better and didn't move nearly as much.
outside of that all bets are off.