Heating process for annealing

P

pso

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Oct 29, 1998
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Hello

I just wanted to ask about the process that one would use to heat up a piece of simple carbon steel, like 1074, in order to anneal it. I realize that the non-magnetic temperature is different for each steel.

What I would like to know is does one put the steel in the oven and leave it in till the temperature reaches to non-magnetic (several hours in the oven that I have access to)?

Is it better to put the steel in once the oven is up to (or near) the non-magnetic temperature, then turn the oven off after allowing the steel to heat up?

Would the shorter exposure to high temperature reduce the amount of furnace scale?

Should I put sacrificial pieces on the top and bottom of a stack so that the "good" pieces are not as exposed while in the oven?

That's a lot of questions. Does my engineering background show?

Thanks in advance for your help.

Phil
 
the most important part of annealing is that you let it cool very slowly after soaking at non-mag, for a couple of minute's put in in verniculite or the forge coals and let cool over night. as even a heat as possilbe normalize's, and the slow cool anneals the steel.
 
If you are trying to reduce the scale on the steel just wrap it in the stainless foil first.You would be better off to let your oven heat up and then do a couple of normalizing heats on the steel---heat it up and as soon as it reaches a reddish orange color bring it out and let it cool to Black in stil air,then do it again---once the second or third time of doing this cools to black then heat it to critical(non magnetic) and shut the door on the oven and shut the heat off and don't open it until you know it has reached room temperature inside the oven,usually just doing this at night and then letting cool til the next day is the best way to know it is cool.Or on the final heat once it reaches critical do as Rhino said and put it in a bucket of vermiculite to cool slowly..
Bruce
 
If you have an oven for annealing the best way to do it is to put the steel in and set the temp to 1325 F for 40 minutes. Let it cool down enough to pick up with your bare hands and it is soft as butter. Non-magnetic is too hot but is neccesary because some people dont have ovens.
 
Ed and I soak 52100 for two hours at 1000 degrees. we do this twice with a twenty four hour wait in between the two cycles. I dont usually even open the door of the oven untill both cycles are completed
 
Dear Sir,
If I were in your shoes, this is the approach to annealing that I would take. There are a couple options depending on where you are at in the making of this knife and the steps you have already taken. However, these steps can follow what you may have already done. I.e. normalizing.
For starters, if you are wishing to promote effective recrystallization from the forging process and a relatively soft material for grinding, then fully anneal it. If you just want the material soft as possible, you want to spheroidize.
For the anneal... bring the temp to 1400°F-1500°F. Place the blade in the kiln once it has cycled. (Foil will help cut down on oxidation and decarburization). After placing the blade in, wait till the temp cycles again, the kiln/oven will have to reheat naturally from opening the door. Soak the blade for 30 minutes once it has cycled. I cannot remember precisely, but try thirty minutes, it won't hurt anything. After time has expired, you can simply shut down/reset the kiln/oven and allow the piece to cool down with kiln. It will take some time and results may vary depending on kiln size/construction and temperature for annealing you chose. Be sure the oven reads temp continuously even while not firing as to monitor the inside temp. Do NOT open the door during all this or back to square one. Just make sure its around room temp when you DO open it back up or at least under about 200°F to be safe. There are other effective ways of doing this including ramping down on controlled temperatures per hour/min and such. But for 1074 and the purpose of a knife, it is not necessary. IMHO. Hope all this helps. Good luck.
 
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