Blade warpage,First time heat treating

Nathan House

Nathan House

Joined
Feb 14, 2000
Messages
1,204
I ground out a nice looking drop point out of 1095
I took it to 220 I ground both sides even,did not heat the blade
while grinding.
My question is what went wrong.I heated it up to a nonmagnetic state
quench it in Olive/minerial oil mix,that was heated up to around 120
the blade warped next to the plunge cut,.
What did I do wrong?
Thanks:confused:
 
Did you keep the heat even on both sides of the blade as you brought it up to temperature before the quench.If you don't it will warp every time.If you added a false back edge before heat treat that will also help cause warpage,Put them on after heat treat.Don't grind the edge to thin before heat treat either..It could have been any number of things that might have caused this,but without being there and seeing what all you did it is hard to tell you what might have went wrong.
Bruce
 
Ragnoor beat me to it. I normalize several times during the grinding process and triple normalize before heat treating. By-the-way, this greatly improves the grain in the finished blade. As Bruce said, any number of things could have caused it. I strongly feel that a knife blade thinks and knows what it wants to be. Some of them just want to be a$$holes!:D :D
You should be able to straighten it. If not, normalize it, straighten it and re-heat treat!:grumpy:
 
I am green at Ht so forgive me for asking this question but what is Normalizeing?Bruce I had the edge at 30 thousandth.I think I will end up using the blade as a patteren and to remember my first Ht mistake.:rolleyes:
warped blade.jpg
 
Nathan, Normalizeing is just like annealing, just different:D :D . There are several different methods but what I do is to bring it to critical temp in the forge and turn the forge off. Let it cool to room temp. This relieves the stress built up in the steel and refines the grain some. Even grinding introduces stress in the blade so it is important to normalize if you forge or grind. It is the one single most important (IMHO) pre heat treat step to be made.
By-the-way.....I like the knife. It would be a shame to not try to complete it!
 
Peter
thanks for the tips,I learned my leason I will do that before I HT any more carbon blades.
Thanks for the kind words about the knife;)
 
Hey Nathan,

Did you fully harden the blade? If so try an edge quench next time. Before I started normalizing I used to have 1095 warp on me all the time but with an edge quench, after tempering I would wrap it in a piece of leather, put it in a vise and just bend it straight:)

Now that I normalize I have had much less problems with warpage.

Chuck
 
Nathan-

I'm glad to hear you're trying your hand at heat-treating. Even if you don't keep it up, just trying to figure out what the steel does in heat-treating will make you a better maker...or so I think ;)

Normalizing, put simply, is stress relief. It is also referred to as a thermal cycle (one of many forms). Normalizing will refine the grain of the steel and leave it in a state that is suitable for machining (i.e. grinding, cutting, filing, etc.).

Annealing can be done by taking the steel up to its required temp and allowing it to cool slowly. The slow cooling allows the grain to be sluggish, big, and fat. A lot of guys think this is a necessary step, but it's really not. Actually some steels are not in their most suitable machining state when annealed. It does make the steel soft.

Now assuming your steel came to you annealed, then you started with a bar of steel with big, fat, ugly grain. Working hard to keep it cool while grinding isn't the best route (IMHO).

You can further refine that grain (from the way it is when you receive it) by doing multiple normalizing cycles on it. Then grind away. When you are done grinding, normalize it again before hardening it.

Taking a steel to austenizing heat and attempting to put it in solution from an annealed state is very hard on the steel and will only cause you problems.

Best of luck! :)
Nick
 
Nick, I was hoping you would give another method to normalize. Yours always seem to come from a lot of research whereas mine come from reading the chicken foot on my anvil!
 
I tried it a second time,I reground another blade,this time I noramlized it,I let it cool and then reheated it no nomagnetic state
edge quenched it.I did not have nay problem with this one.The one small step I did not do on my first try is what cost me.
Thanks for all the help from everyone.
:)
 
Peter-

Hope I didn't crowd in :(

It's just been a really tedious process finding and learning the information and then applying it (for me).

I hope to someday have as great an understanding of the metallury behind knives as guys like Howard Clark and Don Fogg...not to mention their skill at the forge.

I forgot to mention it Nathan, but strongly consider destruction testing your blades. When I first started forging, I had only broken one blade intentionally, and it hurt so bad (figuratively :) ) I figured I'd never due it again.

But when you start breaking your blades it will let you look at the crystalline structure that you're getting which will be indicative of the grain structure. With 1095 once you nail it, you will see a milky smooth grey color in the hardened area. When I first started I had some that looked like raw sugar crystals...NOT GOOD!!!

Once you really dive into this you will most likely want to set up high temperature salt for heat-treating...but that's another thread :)

Peter...I need all the help I can get, so I will be keeping an eye out for a stray chicken!!! :D

Nick
 
Not crowding at all Nick. I ment what I said about your answers. I always look forward to reading them.
 
Nick
Any knowledge I can learn about HT,grinding Fit and finish the better I will be.I am in this for the long hall so all my mistakes
I will learn from them.
This forum is always a good place to go when you a scratching your head about where you went wrong.
Maybe one day I will be good enough to stand at a knife show with some of the people on this forum.:)
 
Hey Nathan, since nobody else mentioned it, NICE BLADE! Seriously, I like that little knife of yours. It kind of looks Jerry Hossomish(which is a good thing), and really looks to be a useful design. Keep it up.
 
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