Tempering, heat treating, annealing ????

Burchtree

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I've read every tutorial I can find about treating a blade. I'm making a 12" fighter and I'm seriously confused about all the processes involved into turning a piece of steel into a usable cutting blade.

It seems like everyone has a different method, or process to heat treat and temper their knives. Now, I'm not sure what I need to do.

I don't have a forge, or any serious equipment, but I still want a decent blade -- i.e. -- springy back, hardened edge.

My question is -- if I heat it to it's nonmagnetic state, then let it cool down naturally, then I've annealed it, right?

After that I heat it up again to it's nonmagnetic state and quench the edge into motor oil. Does this produce a good blade, or do I need to take further heating steps? Do I need to do all the "normalizing" stuff or anything after that?

Sorry, I know you guys are probably thinking you aren't going to touch this with a ten-foot pole, but I could use some answers, and I just want a good, workable blade. I want it done right, but I'm not going to try and win any contests with it.

I appreciate any advice you all could offer.
 
Annealing - heat the steel up to near or above critical and let it slow cool. By slow cool, I mean 50 deg per hour slow.

Normalizing - heat to near or above critical and let air cool

Hardening - Heat to critical or above and quench to transform the austenite to martensite.

Temper - Heat the hardened blade at a much lower temp (ie 350 deg) for a specific amout of time to decrease the brittleness of the martensite.

I think this should help. The others that have a lot more knowledge than me will be able to help out more.

Edited to add: the HT process is very dependant on the type of steel you are working with. If stainless, you will probably be better off sending it to a pro. Regular high carbon, can be done at home with very good results and not much equipment.
 
Yes, I forgot to add, it is high carbon steel. And is it necessary to do all the above steps?
 
Well if your working with a high carbon steel like 5160, 1084,1095 or L-6. this is what I would do. If its one of the stainless steels I wouldn't have any idea.
First off , it sounds like a metal removal knife, sense you have no forging equipment. So if the steel you bought or are using did not come pre-annealed, I would anneal it. Like you said bring the blade up to critical temp (non-magnetic) and place it in a bucket of dry wood ash or verticulite. Be careful at this time and don't overheat, use that magnet and pay attention.
Once the steel has cooled, profile and grind in your bevels, but leave the cutting edge fairly thick (1/16"), clean the steel up by sanding, so the whole blade is free of all grinding marks and the only sanding marks remaining are from 220 grit sand paper.
Now bring the blade up to critical temp again and allow to air cool, this should releave any stress applied to the steel in the grinding process.
Once the blade has cooled to the touch, useing oil for quenchant, I would preheat my quenchant to 125 - 150 degrees, then heat the cutting edge to critical, again be very careful not to overheat, pay close attention to the magnet, as soon as non magnetic is reached accross the entire length of the cutting edge and approx. 1/2 up the blade, quench the cutting edge in your quenchant to the desired depth.
allow blade edge to stay in quenchant until all bubbleing quits and then submerge the entire blade into the quenchant to slow cool, after a few minutes in the quenchant place the blade (after wiping all the oil off) into a preheated oven of 350 degrees for 2 - 1hr. peroids. Then check the cutting edge for brittleness using the brass rod process. if blade chips raise oven temp 25 degrees and continues process until brass rod test is achieved.

Good luck and I hope this helps,

Bill
 
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