Bent blade after HT

rbendele

rbendele

Joined
Feb 9, 2005
Messages
42
Hey everyone. I've been lurking here for about a year now. Everyone has great advice (as well as a sense of humor :D ) and I have learned a lot. I now have an honest, to-goodness, intelligent question to ask.

I heat-treated five 440C blades in one packet and the packet fell over in the oven. Now all the blades are bent. I have HT about 20 blades already and never had this happen before. I normally wrap each blade individually and insure they are straight up in the oven. When I first made the brick holding the blades, I made it to hold six blades, with a slot for each blade. I guess I need another brick with slots for multiple blades or continue wrapping them one at a time.

Now here is the honest, to-goodness, intelligent question - What temperature do I need to take them back up to, in order to bend them back? I hardened them at 1850F for 45 min and tempered them at 200F for 2 hours (x 2).

TIA for any assistance,

Ron
 
On non stainless blades you'd have a better chance getting them straight just at the tempering temp. Hope you learned something about putting all your eggs in one basket. Haven't done any stainless in years but I'd say bring them up to the hardening temp one at a time and straighten then. If I remember alot of stainless is one chance steel. Good luck!
 
Ron: this is why I stopped using that method. You are much better served by putting all your blades horizontally, side by side, in a foil pack and supporting them horizontally on firebricks. All blades must be the same thickness, and you have to press quench using this method.

One packet goes in the oven, you open the door once, slide your tongs under the packet, and remove it to your quench plate. All the blades see the same, uniform heat and they all quench in one operation.
 
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