Heat Treating 4140

A

ajr2000

Joined
Jan 19, 2005
Messages
2
Hi all,

I'm new around here, and I'm looking for some advice on how to harden 4140. This isn't quite for a knife, but I am cutting things. I happened to find this forum on google. These are weapon teeth for a Battlebot (like you may have seen on TV) But, smaller. They will be 2"x1"x0.25" with 2 holes. Basically I wat to harden it myself.

So far I have gathered that I should:

Heat it up to cherry red.
Quench it in oil.

What do you guys think about this? Remember, it needs to be able to hit things very hard and not crack. (RC 40 would be great) What, if anything should I do for a temper.?

Thanks,
Andy
 
As you say, you don't want to harden it. If it is hardened, it will have a tendency to crack. The Battlebot teeth are supposed to be tough not hard. With its ca 0,40 % Carbon it will not be hard too much. You can heat it with a torch as this steel responds flame hardening well and quench in a preheated oil. However you are advised to normalize it before hardening. It will harden to 50-52 HRC. As you want it to be shock resistant, temper it for minimum 1 hour (around 800 F) , tempering will lower the hardness to mid RC 40's and increase the toughness.


http://www.geocities.com/SiliconValley/Campus/8262/htdocs/steels/4140.html
 
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