Normalizing vs. Thermo-cycles: What's the difference? How many? Heat Treating Knives, Knifemaking
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- čas přidán 3. 09. 2023
- This video is intended to address a question from a viewer concerning the difference between normalizing and other heat cycles prior to hardening the blade.
I'm primarily speaking from my preferred steel of 52100, but the general principals will apply to other steels like 1080, 1095, etc.
Some things, like the alloy banding, are specific to steels with some alloy content as the name would suggest (and high carbon) like O1, 52100, etc.
I've spent a lot of time researching heat treating steel for knives, and
these efforts have been focused on a few steels, and primarily 52100, as I find it to be the best all around choice for a high carbon steel blade. Additionally, I have specific heat treating goals, and my processes and the way I employ techniques are dictated by these goals.
Specifically, I want excellent edge retention, and a decent level of "toughness". My knives are designed to cut, and cut well. They hold an excellent edge, and sharpen easily. 52100 has properties that lend itself to these goals, when properly heat treated.
I hope this video helps you in your shop, as you take this info and learn how to apply it to your specific shop and goals.
#blacksmith #knifemaking #forging
firecreekforge.com
/ firecreekforge
I'm the one that asked the questions in the last vid! Thanks for doing a video on this!
Thank you for the information. I will keep that in mind as tonight I'm going to be hardening a piece of layered steel I forge welded the other day. It's mainly 1095/15N20
I absolutely LOVE your metallurgy lessons 👍. You have great insight and explain it well, especially considering that you have no phase diagrams to show, no black board to draw on. You should show us the phase diagrams 👍👍
I have a Masters Degree in Geology, learned about both binary and ternary phase diagrams, but did not look specifically into metals/steel. I have bought a textbook about metallurgy for engineers a long ago, but never read it. You inspire me to do it.
Keep making nice blades (you for sure have the right knowledge to do it) and nerdy videos, it is MUCH appreciated 👍👍.
Oh wow. Didnt realize you were in texas. Im in houston.
Ive watched your videos for a while.
Dont think ive commented. Of if i did it was a while back.
Btw. Just started this video. But i wanted to say. You explained the forge heat treatment on 52100 very well. That video is like 7 years old, but the metallurgy info in it is solid. Definitely respect someone trying to share knowledge about this stuff.
Very informative video, good job.
Good stuff, metallurgy isn't so easy for me to understand, so it's pretty nice to have someone simplify it, thank you for the videos
Thank you for sharing your obsession. High level detail. My hero!
Not for nothing, but I just read your how-we-started page on your website. Very cool, sir!
Your knowledge of metallurgy - and the blade-smithing craft - is impressive. It is clear the craft is your passion. good vid!
Thanks!
What a great video Elijah! Very well laid out and done thanks again!
I would like to see your 52100 process. I have quite a bit of it. I have been a little apprehensive on using it due to the chromium.
Outstanding video, my brother!!! I will definitely be watching it multiple times! Thanks for sharing, and God bless you! 💯🙏🏻😎👍🏻🔨🔥🔪
Thank you!
you are my man 🙂🙃😉
I think it looks good 🤠
Thanks!!
Сколько полезной информации,спасибо.Скажите пожалуйста из за наличие какого элемента в стали отпуск необходимо делать на высоких температурах?
Nice hat!
Thanks!!
I’m interested in more details in (52100. Forging wise not much out there. I forge it around 1750-1800 whether or not it’s right it works for me. Thanks
I was interested in doing a thermo color on my Spyderco with cpm s30v steel but I don't know if this would ruin the heat treatment
Yes I think it would ruin it, also the color would not be durable
What would you recommend to make a colored thermos in cpm sv30 steel? In my mind I thought that with 550 f for 45 min I could do it well.
I have my cowboy hat on for my website picture 🤠
Im a fan of your stuff brother, and you understand metallurgy, but i gotta push back on one part of this.
I start off by saying i forge knives as well as use stock removal. I love forging.
That being said, your statement of "how a FORGE blade can be superior to a stock removal blade" is incorrect.
Your description of lowering your forging temp gradually that will form crystallization has nothing to do with FORGING.
Its simply manipulation of heat.
Its a thermo cycle.
Shortly after you made that statement you talked about how there are all these temperature techniques including GRADUALLY decreasing temperature in consecutively cycles... thats exactly the same thing.
The fact is steel is a stable organic material. Like a rock. No matter whether you forge, or stock removal.. the changes that take place are due to TIME AND TEMPERATURE... NOT the actual hammering if the steel which is what forging is.
Forged blades and stock removal blades can only be equal because they are made of steel.
Hammering steel does nothing positive to the micrstructure to the steel. All the stress and grain growth can absolutely 100% be removed through a proper heat treating protocol.
You can make the case that a forged blade has more a chance of being inferior if the Smith doesn't know the proper heat treating protocol..
Your talk at the end absolutely alloy banding being a themo cycle process thats somehow exclusive to stock removal is incorrect.
You will get alloy banding with a forged blade if you do what you said by using cooler and cooler temps when forging.
"Thermocycling" (cooling in still air) only happens when you bring the temp at orabove austenitizing temps. If you do not reach austenitizing temp... the internal structure of the steel cant move.
This is why normalization takes place before annealing. Annealing uses temp under austenitizing but long times at that temp to shink grain.. but no carbide is moving.
Yes; and not quite.
For clarification:
That is correct, I was basically describing a form of thermo cycling that takes place during forging, and how to do it correctly. You could do these thermo cycles apart from forging as well. I did not call them thermo cycles, as I was speaking in the context of forging, but yes it's basically the same thing.
What is not correct, is that hammering does absolutely nothing for grain refinement. How much exactly is debatable and varied, but as I mentioned in the video, there are two ways in which grain refinement occurs. One is thermocycling. The second is recrystallization. This happens when dislocations are created in the steel by working it mechanically instead of thermally. Dislocations are re-nucleation sites, and grain refinement occurs upon reheating the steel to austenitizing temperature, where a new, higher number of grains are formed.
Finally, if I made it sound like alloy banding only occurs in stock removal blades, I did not mean to. You are correct, alloy banding will occur in either forged or stock removal blades. Again, this is specific to steel with some amount of alloy content, which I don't think I pointed out. Multiple grain refinement cycles on something like 1080 or 1095 is not going to result in alloy banding. It is, however, a longer route to a similar result of grain refinement.
Additionally, carbon does in fact move at temps below austenitizing. The DET annealing process is designed for this, which I mentioned in the video. Another example is tempering, where controlled amounts of carbon are released from the tetragonal martensitic structure.
And, for the record, I also use both forging and stock removal. I think you can create an excellent blade from either method, and one isn't inherently better. I believe there are specific techniques that should be employed with either method to get the best results, and describing the forging process like I did is an example.
Thanks for watching!
@FireCreekForge I appreciate the explanation.
We still disagree on the recrystlazation.
I'm not a metallurgist, just a metallurgy nerd like you, but all the stuff I read on recrystlazation in steel is that it POTENTIALLY can happen from mechanical damage. And that what's happening is the grain cell gets deformed, then is basically absorbed by surrounding grains. That leads to increased grain size. Something that isn't good for steel.
But honestly I don't think it matters at all because the second you thermo cycle or anneal the steel... the grain growth is all gone.
That's the whole point of thermo cycling and annealing after forging in the first place... remove the damage done right??
I'm a caveman and probably am misunderstanding it but the way I see it because steel is a crystalline structured material, it's extremely predictable. So no matter what you do to it (structurally) you can always return it to any state you want with time and temperature.
I say this to the guys who hate on forging too. All the stress they claim is in the steel I can remove. I can put the steel in the exact state it was when you bought it from the mill.