help fixing a curved heat treated blade

damon lusky

damon lusky

Joined
Feb 14, 2013
Messages
224
So the dilemma is im working on a 13" blade made of .120 damascus from alabama damascus. Its a long thin knife only 1.25 high. I left it its full thickness so the only grinding that been done is its original precision alabama did and my profile. I carefully lowered it tip first into my warn oil and with no side to side movement pulled out a curved blade?

Any advice out there? How to fix it now? and or how to prevent this in the future? Thanks
 
i use a piece of angle iron, a couple metal clamps and some metal scraps as shims.

Clamp blade to angle iron with the curve facing away and using shims to space the blade off the angle iron. (so that you can bring the blade a little past straight) put the other clamp near the tip but just snug, don't try to bend it back yet, and place the whole shebang into my tempering oven. When the whole mass has come up to temp, i snug up the front clamp to bring the tip just beyond straight and place back in oven to finish temper cycle. Pull it out and check. If its not straight, i add more pressure and take it further beyond straight and temper again for another hour.

On prevention, did you normalize the blade before quench?
 
Thanks for the tips guys. I ran one 2hr cycle last night and it seems to be working. Just a little more tweaking. Maybe one possibly two more cycles will get it.

Is this typical with damascus? Ive always used precision ground stock and never had issues like this. Is there a normalizing process pre heat treat that might help?
 
Alabama Damascus can bend like a banana sometimes. It needs to be normalized. I do a three step thermal cycle before hardening.
 
Please share your formula with me :) temps and times you run for your normalizing cycle? I like the material but when you say banana you really mean banana! I'd love to avoid the straightening when I temper if possible or atleast avoid the 2" curve I got this time. Thanks

S.Alexander said:
Alabama Damascus can bend like a banana sometimes. It needs to be normalized. I do a three step thermal cycle before hardening.
Click to expand...
 
For sure. Here's what I have done, and all my blades came out straight. I ground my bevels in before heat treat as well.

1650 cool to room temp
1550 cool to room temp
1450 cool to room temp

Then austentize 1500 for 15 minutes and quench in canola oil.
 
S.Alexander said:
For sure. Here's what I have done, and all my blades came out straight. I ground my bevels in before heat treat as well.

1650 cool to room temp
1550 cool to room temp
1450 cool to room temp

Then austentize 1500 for 15 minutes and quench in canola oil.
Click to expand...


After 3 temper cycles and its getting better each time. I haven't had much experience with Damascus or forged knives so thanks for all the help guys!Ill post a pic if i ever get it straight :)
 
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