Post heat treat warp

A

amamachinist

Joined
Jul 6, 2012
Messages
136
Hi guys and gals

I heat treated my knife on my own in a somewhat cheap and not recommended fashion. Now it's warped. Is there anything I can do? Or should I just chalk it up as a learning experience?

Thanks in advance for any help

Nick
 
Not the best pictures but It shows how warped it is

c50f5629.jpg
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0a895ebc.jpg
 
Describe your knife and your process please. What steel, how did you HT it?
Also, did you temper it?
 
Often you can reheat the material, bend it straight, then re-heat treat it.

The main culprits for warping is not have the grinds symmetrical (one side ground deeper than the other), stress in the steel (normalize prior to ht to prevent it), moving the blade sideways on the way to the quench (always move the piece as if you are trying to cut the air..with edge forward), and holding longer blades sideways when hot, where the weight of the steel drags the blade towards the ground creating a warp.
 
dperk said:
Describe your knife and your process please. What steel, how did you HT it?
Also, did you temper it?
Click to expand...

Ok it's a little embarrassing because I know it's not ideal. But I started with a piece of .156 O1 cut out my shape on a mill. And grinded the bevels with my 1x42 belt sander down to 320grit. It looked pretty good I thought the grinds were even. Then I held the knife in a pair of Kant-twist clamps with the blade pointing up in the air and heated it up with a propane/oxy torch. I thought I could keep a fairly even heat because I'm a glassblower and decent with a torch. Anyway I heated it until a magnet wouldn't stick then kept the heat as even as I could judging by color for 17 minutes. I then quenched it in oil and then tempered it in my oven at 550 for 2.5 hours. I thought it looked good going into the oven but it was quick so it may have already warped at this point. I know that this process is very flawed and I understand why it warped. I am working on making handles and the style I'm trying is permanent. So I wanted to get at least some hardness to it before I put the handle on. And I didn't want to wait for a professional heat treat because I'm still in prototype mode.

Thanks again for the help
Nick
 
you can often heat it to tempering temperature and bend it the other direction. I have done this unsuccessfully because I was wussy about it. Then I was shown how it's done...
 
Well. I think your tempering temps are a bit high. The way I learned to straighten warp successfully on 3 blades now is if it's warped from the quench, I clamp it so it's straight, onto a piece of angle iron. There was a great thread on this by Rick Marchand.
Then I tempered my blades at 400 for and hour twice. Most of the warp was gone the first temper cycle and a little bit more on the second on a 10-1/2" blade I'm working on. I'll be able to get the rest on my finish grind/sanding.
With that said. This is the link where people more experienced than me talk about this method in detail.

http://www.bladeforums.com/forums/s...g-The-Temper?highlight=Straighten+warp+quench
 
Brian Ayres said:
The way I learned to straighten warp successfully on 3 blades now is if it's warped from the quench, I clamp it so it's straight, onto a piece of angle iron. There was a great thread on this by Rick Marchand.
Click to expand...

This works well. I've done it many times.
 
I found the link for you. This technique has saved many a knife for me. Only advice, it's tricky to find the right amount of clamping pressure so that you don't over correct and warp it in the opposite direction.

Rick's warp post
 
Its 01

You can just redo the heat treatment again. It is very forgiving that way and this time make sure it is straight and temper at 400-450 depending on what Rc you want.
 
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