Reducing Oxidation and Slag? Annealing styles?

J. Keeton

J. Keeton

Joined
Nov 15, 2005
Messages
1,218
I was wondering if yall could help me out with this little annoyance I've been having. It has to do with Oxidation and Slag on my billets. I was wondering if there is any way to bring the oxidation and slag down to a minimum. It's a supper pain in the ass to grind it all off.

Also when yall anneal your blades. What methods do you use to let it slowly cool?

Thanks,
Jimmy
 
I assume from the avatar that you are using a gas furnace . Flame adjustment is the start .A neutral or slightly reducing flame will minimize the problem.Care with the temperature is important too -the higher the temperature the faster it will oxidize.....Annealing , you could leave it in the furnace and shut off the furnace .You could bury it in ashes .
 
you can use anti-scaling products like the ones from Brownells for any of the thermal cycles other than welding or forging. For those steps, you can only try to reduce the scaling like was previoulsy mentionted. It works just as well for annealing and normalizing as it does for quenching. Just don't let the 1600 degree stuff get over 1600. It tends to harden and stick. Also don't let any bubbles form
I have a garbage can full of two year old vermiculite from Home Depot. People say that it should be no good by now because it sits in my garage in Florida and has probably absorbed a bunch of moisture, but it will anneal W2 in about 8-10 hours to the point that a 6 1/2 inch x 3/16 hidden tang blade can be twisted by hand in a vice like a pretzel. I know....i did it to one of my screwups....lol I'm not sure about stainless, but for plain old carbon steel, you do not need a heat treat oven to anneal. I can hold my forge at critical temp +- 10-20 degrees for a pretty good period of time for soaks, etc. and the vermiculite seems to very well. You know if W2 is not annealed because you can't drill into it in its hardened state with HSS or TiN bits or end mills even after proper tempering. And unlike 1075 or 5160, drawing a W2 tang with a torch until it is pale purple after the fact after the fact doesn't seem to help the process much. I put clay on the tang of W2 blades now even if i am totally hardening the blade.
 
J,

After welding and forging the billet I reheat it to normalizing temps, several

times.

I apply borax and use a wire brush to remove scale in between heats.

My annealing pan uses spent coke with a 2" Kao wool blanket to insulate.

Good to hear you got the press working, Fred
 
I guess your talking about damascus billets. Get a large angle grinder, belts are little good on flux and scale.
 
Be VERY careful with vermiculite as many sources have been found to be contaminated with asbestos, from what I read. I hear regular old lime also availabe from nurserys works well.
 
It does sound like you are forge welding and have trouble with the flux clinging to the billet or blade. I like to slide a piece of sheet metal in under the work so the slag can collect on it until the welding is done. Remove the sheet metal and begin forging and wire brushing the work at progressively lower temps until all the flux is gone. It helps to wet brush to pop the scale off too. Try not to move metal with scale on it because the scale will push deeper in your pattern and cause you more grinding to remove it. Be sure the wire brush is the heavy duty type made for that purpose. I bought mine from Centaur Forge. Its one mean wire brush. I sometimes use a grinder between heats if all else fails.
 
This is how I anneal. I have a cart with a large draw, in the draw and top of cart I lined with fire brick. The draw is filled with ash and sand. I heat the sand up with wrought iron anchor links cut in half, that I have at welding temp. After I put the half links in the draw, I bring the billet to non-magnetic and put into draw and cover it up with the sand/ash. Then I heat up more 1/2 links and put on the top. I leave it in the draw all night. Have fun and good luck.:thumbup:
 
Hukk, you don't have to worry about newly bought vermiculite. It has no asbestos. Even the old stuff might not (not that I would press my luck). The Air Force sent me to a lead based paint and asbestos familiarization class. I guess everyone who works for the civil engineering squadron has to take it, at least at this base.

-Mike Sheffield
 
J. Keeton said:
I was wondering if yall could help me out with this little annoyance I've been having. It has to do with Oxidation and Slag on my billets. I was wondering if there is any way to bring the oxidation and slag down to a minimum. It's a supper pain in the ass to grind it all off.

Also when yall anneal your blades. What methods do you use to let it slowly cool?

Thanks,
Jimmy
Click to expand...

Not to thread-jack here by wow, Keeton your only a few miles away from my house! I have been trying to set up a forge for a while now. Just wanted to say hi and nice to see a fellow South LA guy on the board!
 
Thanks for all the replies! I now have a lot of things to try out. I think I am going to look into a very large angle grinder to cut down on my scale removal time.

Also I think I'll use some inswool and make a "sheath" for anealing.

Peldor said:
Not to thread-jack here by wow, Keeton your only a few miles away from my house! I have been trying to set up a forge for a while now. Just wanted to say hi and nice to see a fellow South LA guy on the board!
Click to expand...

Hey thats cool man. I don't see many guys who make knifes from Louisiana. :thumbup:
 
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