Heat Treating Scale Prevention?

B

BearPawBlacksmithing

Joined
Mar 27, 2017
Messages
83
I use a propane torch and a vat of oil for my heat treating of carbon steels and I always seem to get a lot of scale build up. It would save a lot of sanding if I didn't have all that scale bubbling up, and beings that I don't have a belt grinder all of my sanding is by hand. It takes a long time to get it down to where I can't see where it bubbled up.

So my question is what do you guys do about scale build up? Or do you not worry about it because you can just grind through it?

Can I use some sort of flux to prevent it?

Thanks
Izaac
 
If my eyes are right, the PCB compound Nathan linked to will only handle temps up to 1650F. Is that right guys? I'm using ATP641 and LOVE it. (flakes off during cycling....don't like that part) Rated up to 2300F.
 
I recently started using ATP 641 and it works well. I was using a very light mix of satanite previously and that works pretty well too.
 
i use PCB as well (carbon steels) and even though it does wonders in term of anti-scaling i have noticed it is not as effective when it comes to protect from decarburation.
That's it, i get super clean steel from the HT, but it requires a fair bit of sanding to get back those 2-2,5 HRC lost at the very surface.
Did you experience something similar with PCB? Does ATP641 works better?
How thick should i build a layer of the stuff? I just get full even coverage, without bumps and bulges.
 
For the OP
Aside antiscale compounds, you should avoid lean flames, try to reduce the air to fuel ratio and possibly build yourself a forge
 
No I get the same thing with ATP. A little decarb layer.
 
For me it depends on the heat as to how much decarb I'm getting with the ATP641, but it very minimal regardless. No where near like HTing a blade naked! Higher heat and longer time(A2 for example and extended soaks) will add to that problem, but ATP641 does a very very good job in mitigating the decarb and scale issue. I've heard PCB will stay on during cycling, that you have to almost scrub it off (not sure...never used it), whereas the ATP will flake right off in an air cool during normalizing/cycling, and must be reapplied. I don't mind. Even a quart of the stuff goes a long way.
 
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