Heat anodizing steel - does it last?

[ilikegunspdx]

Did some heat anodizing to the barrel of a heritage 22 and looks really cool with deep blues and yellows. My question though is will this last or will the color change over time etc. thx!

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[Geardo]

Usually changes with wear in my experience. Unless case hardened.

You could clear coat it?

 

[ilikegunspdx]

Clear coat is a good idea. I still have some left form painting a car in my driveway. But it's high gloss and a more matt finish would look better. The automotive polyurethane clears sure last though.

 

[Flymph]

Would a clear coat hold up to the heat and expansion?
You could try it!

 

[ilikegunspdx]

Would a clear coat hold up to the heat and expansion?
You could try it!

I think it would be fine for this little 22. The barrel thickness is like a big 45lc barrel with tiny 22 hole in the middle. Plus single action slow loading so shouldn't heat up too much.

But if it was a semi auto with large capacity mag that might be a different story. Only one way to find out ha ha!

One issue I ran into is that it's really tough to get any decent color on the cylinder cuz it's such a huge mass of steel. The hole thing tries to heat up fairly evenly even when heating just a small portion. Maybe there is a way to heat one part of cylinder and keep the other parts more cool like using wet felt or something. Need to experiment...

 

[Member 5605]

You mean color case hardening?

If doing that, why shellack it? Let it ride and wear on its own patina.

 

[GSample]

You must be using another process given that the Anodizing process is not capable of being applied to steel, only aluminum & magnesium.

 

[Stomper]

C'mon.... he meant case hardening.... pretty colors!

 

[ilikegunspdx]

Re case-hardening it is beautiful but is way, way beyond the amount of time I would be willing to put in and requires special equipment and materials.

Heat anodizing the barrel takes about 15-20 min with just a torch. Of course it creates a totally different look than case hardening. I might also try jeweling the barrel and then heat anodizing it just for fun. That would probably look over the top though but who knows until u try.

 

[Ownerus]

C'mon.... he meant case hardening.... pretty colors!

Actually old style case hardening appearance. Actual case hardening involves introducing carbon into the surface followed by quench and temper to give actual hardness. I think modern "case hardening" colors are produced by a chemical surface treatment. The colors derived from heating the steel are oxides and very thin and largely temperature dependent. They usually won't have the blotchy pattern of color case hardening because you can't get the sharp temperature transitions that would take. And if you can, it won't be good for the strength of the steel. Especially anything not just mild (low carbon) steel.

 

[Stomper]

Actually old style case hardening appearance. Actual case hardening involves introducing carbon into the surface followed by quench and temper to give actual hardness. I think modern "case hardening" colors are produced by a chemical surface treatment. The colors derived from heating the steel are oxides and very thin and largely temperature dependent. They usually won't have the blotchy pattern of color case hardening because you can't get the sharp temperature transitions that would take. And if you can, it won't be good for the strength of the steel. Especially anything not just mild (low carbon) steel.

Whatever..... metallurgy nerd.

 

[Ownerus]

LOL. That's AMATEUR metallurgy nerd there buddy!
Case hardening gets underestimated I think. It's not just a pretty face. Given the right steel and heat treat, case hardened parts serve in some of the toughest applications like heavy duty gears.

M1 Garand receivers were case hardened and in Hatcher's blow up tests of WW2 rifles, came out on top IIRC from reading it 40 years ago. A very hard wear resistant surface supported by a really tough core.

 

[RangerArms]

Would heating with a torch possibly warp the barrel? I'd be worried about messing that up but maybe it's different for barrel steel?

 

[Ownerus]

That's a distinct possibility. One could relieve existing residual stresses or introduce new ones.

 

[ilikegunspdx]

If you don't have a blowtorch, you can just shoot it full auto until you get the color u want. Saw this 22lr full auto torture test which made the silencer change color. I think the suppressor is titanium though not steel, but same effect. I put my barrel in vinegar overnight and all the anodizing came off so it's about the same as bluing on the comes-off-with-vinegar scale ha ha.

 

[mignuc]

If you want to heat treat a cylinder in only one area (or one chamber at a time), machinists use a heat-sink paste of some kind. You should be able to heat treat around one chamber by putting the paste on both sides of the area you want to work on. I've never tried it because I've never had a need for it, but it sounds just like what you need. Try going to MSC online. They have everything for metalworking. If you do, let us know how it comes out.

Here is also a process that might help with actual case-hardening. Cheap steels cannot get very much harder because they have virtually no carbon in the steel. However, carbon can be embedded (up to about 0.020" deep, the same as commercial case-hardening) by doing a process called carburizing. It involves packing charcoal tightly around the cheap steel and then heat treating it. The surface steel absorbs some of the carbon to form "carbon steel", which is the kind that can then be casehardened. I don't know too much about this process other than that it exists. Caution: this process probably requires the item to be heated for hours or it won't work. You'd have to find out before trying it.

While it may be too complicated for a hobbyist to do, I'm sure there are shops that can do it for you.

 

[GSample]

Carburizing IS case-hardening. There isn't a secondary or additional heat treating process for gaining hardness after the part has taken on carbon. That all happens in the carburizing process. Quench (air, oil or water depending on the steel type) follows.

 

[thorborg]

Neighboring farmer used to toughen parts of his equipment subjected to heavy wear, including tracks roller bearings run on with a stick welding setup that used a special rod of some sort. He would flow the rod material on the surface but I don't seem to remember it leaving a build up. I don't know if there is a thickness to it, or it there is, if it is controllable. I do know it extended the life and in some cases reinvigorated the materials of his equipment considerably.
I don't know if it could be done to a barrel and can't remember if it left purdy colors. He called it surface Case Harding. It did not seem to distort thinner material.
Come to think of it, doesn't look like I know much at all. Maybe someone here is privy to the concept and if it could be applicable.
Personally, I wouldn't.

 

[Flymph]

Can we get some pictures?

 

[ilikegunspdx]

If you want to heat treat a cylinder in only one area (or one chamber at a time), machinists use a heat-sink paste of some kind. You should be able to heat treat around one chamber by putting the paste on both sides of the area you want to work on. I've never tried it because I've never had a need for it, but it sounds just like what you need. Try going to MSC online. They have everything for metalworking. If you do, let us know how it comes out.

Here is also a process that might help with actual case-hardening. Cheap steels cannot get very much harder because they have virtually no carbon in the steel. However, carbon can be embedded (up to about 0.020" deep, the same as commercial case-hardening) by doing a process called carburizing. It involves packing charcoal tightly around the cheap steel and then heat treating it. The surface steel absorbs some of the carbon to form "carbon steel", which is the kind that can then be casehardened. I don't know too much about this process other than that it exists. Caution: this process probably requires the item to be heated for hours or it won't work. You'd have to find out before trying it.

While it may be too complicated for a hobbyist to do, I'm sure there are shops that can do it for you.

Cool thx! I didn't know that stuff existed. Makes sense. All one would need is some kind of heat sink that affect only a part of the part being heated.

Re hardness, not looking for any hardness benefit at all, just something different than blues finish.

I tried jeweling the frame and it was so shiny it kinda looked like something Goering or Liberace would own. So then I went the other way and antiqued it (frame I mean). Kinda cool, looked like old colt SAA. Now I want to see what the bright colors will look like in combo with satin metal frame (or heck, polished, jeweled again? who knows).