annealing

Karl B. Andersen

Karl B. Andersen

Joined
Jul 27, 2003
Messages
5,615
Okay.
Dilemma here.
A chance for the "smart" guys to teach me sumpthin' - I hope!
I'm continually reading conflicting procedures.
When I'm annealing, after forging and normalizing cycles are done, do I bring the blade just up to dull red, just below critical, where the blade is still actually magnetic?
Or do I take it up to where it is just turning non-mag? Why/why not?
Do I air cool or insulate to slow cooling?
If I'm not paying attention and the blade gets up to full non-magnetic, bright red, have I hurt anything? It's not going to be there long. Just a few seconds.
What's the advantage to just up to a "dull red" as opposed to a full non-mag?
I'm using 5160 and coal, over which I have a great deal of control.
I'm using lime, instead of vermiculite. The lime does a MUCH better job of keeping the blade insulated. Hours later and the blade is still hot if I "sandwich" it between a couple hot bars.
I'm no metalurgist, and have no dreams of becoming one. So don't use super-exotic words in your description!
Anyway, got some help?
 
I bring the bar to nonmagnetic 1325f and hold it for 30 minutes and let it cool in the Evenheat oven. You could do basically the same thing with your method. The bar just needs to stay close to nonmagnetic for as long as possible and cooled slowly. sandwiching it with heavy bars will really help hold the heat.
 
Annealing is often done before forging.Stress relief and Normalizing after.
To anneal bring the steel to non-magnetic and hold for a short time,say 5-10 minutes.Place in an annealing box (ashes,vermiculite,etc) and let cool slowly for at least 6 hours,the slower the better.The idea is to cool it 50 to 100 degrees per hour.A programmable oven is the perfect way to control this rate.The steel should be annealed then.The things to watch out for are overheating and holding too long.Both cause grain growth.
This is just a basic annealing process,but if you really want to know what is going on with those atoms,read up on spheroidizing,normalizing,annealing,and heat treating in general.An excellent book on this is "Metallurgy Theory and Practice" by Dell Allen.If you want the complete word from the gurus offer to take Kevin and mete to dinner and beers,your treat.
Stacy
 
Stacey, you mean I can get compensation for my work ? I've answered this question on another forum. Learn more about metallurgy so you know what you want and how to get it.
 
I dont understand the bit about annealing before forging.....why is it necessary?

Thanks.
 
Simply stated,it is easier to forge laminar pearlite than the harder structures.
 
I've never understood that either, wouldn't you just be forging austinite either way?
 
bladsmth said:
Simply stated,it is easier to forge laminar pearlite than the harder structures.
Click to expand...

Steel is heated into the austenitic range then forged. What ever microstructure was present before heating should be gone and only austenite left. You forge austenite!

Jim A. Yorktown
 
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