? on heat treating

E

exsanguinate

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Nov 3, 2000
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140
I finally got my blade flat ground, but I started out with a piece of 1095 that was slightly warped. I tried straightening it, and it is close. I really don't want to spend the money to have Rob heat treat it (in case it warps bad again), so I want to try the torch method.

I looked at Engrath's web page and it mentioned to quench in brine and draw immediately. What does he mean by draw immediately? After the hardening, how do I temper the blade?

Thanks in advance.
 
Draw is another term for temper as in draw the temper. Actually I would use veggie oil or transmission fluid for the quench. Brine is pretty radical (crack, warp pop) if you do use brine make sure you keep it in a covered container preferabbly outside the shop, unless you really like rust.

Brine is usually used with a lower carbon content steel.

If you want to try a water quench try plain water first.

Oh yeah, when heating with a torch, warm slowly, both sides of the blade, then bring up to temp, keeping both sides even by constantly and quickly heating both sides, did I mention heating both sides evenly?

You mentioned warp is it from the grinding?
Make sure the grinds are even.

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Sola Fide
 
MikeS, thanks for the reply. The steel was warped prior to grinding.

So, after I quench the blade in tranny fluid, I immediately place it in an oven at 400 deg for 2 hours. Is this correct?? How long do I leave it in the tranny fluid?
 
Turn the lights off in the shop, find the magnet first, Using the torch warm the blade until the shadows are gone and it is nonmagnetic. Heat just a few seconds more and quench quickly into warm (125 degree) lightweight oil. I use 5 weight for 1095. Water may crack it. I like the edge to be harder than the back so I heat just the edge and quench the entire blade. (The temper line will be straight if the heat was even.) clean with soap and hot water to get the oil off or the wife wont let you use her oven again. Put it in the oven for 1-2 hours at 375 to temper the too hard edge. Take it out and give it a temperary sharp edge. flex the edge on a 1/8" brass rod. If it flexs and chips it is still too hard and the tempering heat will need to go to 400. If it flexs and stays bent it didnt harden or the oven temp was too high. 375 isnt very high, more than likely it didnt harden in the first place. It will need to be hardened again, possibly with water this time but in and out very quickly with the quench to keep it from snap crackle pop. Do I make sence? Bruce
 
Normalizing the blade prior to hardening will help mucho from keeping the blade from warping. Heat to non magnetic and let cool, then harden and temper.
 
Draw tempering is the old and hard way to temper steel although "Draw" is used as a catch word for tempering sometimes. In short after hardening you reheat one end of the work to dull cherry and quickly polish the sides with a stone. This is to see the colors. When you reach the desired color(hardness), quench. Don't try this unless you just want to see how it's done. The advice you have already gotten is sound.
 
I normalize after grinding. If I got a blade that is warping from grinding, I just keep straightening it till I am done grinding. I only normalize carbon steels.
 
Normalizing is a must on forged blades but I have never had a warping problem on 1095 as it comes from the mill. It is supposedly normalized and annealed already. it is easy to bend annealed steel with your bare hands. I think that if the steel is warping as you are grinding you are getting it too hot on one side at a time. Useing new belts will prevent over heating while grinding. Just my thoughts on the subject. Rob has done many more than Myself, he knows what he is talking about. Bruce
 
Thanx again for everyone's input. I finally got my scrap blade treated. The propane torch and gas stove didn't quite get the temp up (dull red). I fired up my outdoor portable propane burner, got the color to orange/red and quenched it in water (per Admiral steels FAQ page). Tried flexing the edge on a piece of brass (couldn't do it), file skips across surface when drawn. Does that sound right as far as hardness?

BTW, can I use patio blocks as fire bricks to keep the heat in????

[This message has been edited by exsanguinate (edited 01-02-2001).]
 
I do not even temper immediately. I use the torch at my job and heat to non magnetic. I have done it enough already that I have the color of the steel in memory. I quench in used motor oil and tranny fluid in a coffee can that I preheated and checked with a thermometer to make sure it is about 125. When it is cool I wipe off and wrap in a shop rag and transport it home(15 miles) Tehn when my wife is done with the oven I preaheat it to temp and insert blade.

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" I am a shootist."
Clay Allison
" Does this mean we are bladists?"
Vaquero57
McAlpin Bladesmithing
 
I would say that if you havent tempered it for at least one hour in the oven at 375-400 degrees that is way too hard and is brittle. You cant do the edge flex test until it has been sharpend. If you dont temper it the blade will snap in half under any amount of use. A file is about the same hardness as an untempered (full hard) blade. Put the file in the vice and try to bend it. It will snap in half for sure, so will your blade until you take that brittleness away by tmpering. Email me if you like, happy to help. Bruce
 
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