Recommendation? Heat Treatment Questions

B

Bobbynickel

Joined
Jun 3, 2024
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Hello, I am new to knife making and have some questions regarding the heat treatment process. I have done some individual research but I tend to get some contradictory results. I was wondering if I could get an idea of the order to heat treat the blade in. I just recently bought 6 pieces of 1095 stock metal. The source was Amazon, so based on what I have read I should normalize just to be safe and then shape the blade form there. My question is when during the process should I anneal the metal? Or if I even need to.

My understanding is that annealing is basically just slow cooling of the metal while normalization is rapid air cooling. However both processes are intended to soften the metal and make it more malleable, with annealing making the blade slightly softer than normalizing. Since normalization si easer than annealing I was wondering if I could just get away with just normalizing. So my order would go, Initial normalization, blade forming, final normalization, heat treatment + quenching, and finally tempering. Where in this process do I include annealing? Or do I even include annealing?

Thanks for any help. I apologize about the long winded question.
 
Welcome Bobby. Fill out your profile so we know where you live and a bit about you.

There is a lot we need to know to give you a full answer.
1) Are you grinding the blade to shape or forging it?
2) Are you using a torch, forge, or oven to do the heat treatments?
3) What condition did the steel come in - HRA, HRPA, CRA, ??? Did the seller say it was annealed. It is usually shipped annealed from knife suppliers.

Annealing makes the steel softer by changing the structure to pearlite. If it needs to be annealed before starting to grind or saw the blade shape and bevels.
If forging, the annealing is done at the end of the day's forging session. If sawing and grinding to shape, it is done to the bar before starting.
There are a number of annealing methods, again, depending on your equipment.
Using a HT oven, you can do a DET anneal, or slow oven anneal. Using a torch or forge, you can bring the steel to just below non-magnetic and then slowly cool in vermiculite.

Normalization is part of the final HT process to bring the grain and structure to a uniform point before converting to martensite in the quench.

The stickys has info on annealing and other metallurgical stuff. There is a Custom Search Engine in the stickys that you can use to search any topic. Put in "annealing" and you will get hundreds of past threads.

Finally, I highly recommend you get the book, "Knife Engineering", by our resident metallurgist Dr. Larrin Thomas (son of Devin Thomas). It has more info that you can imagine. His site Knife Nerds is also a great place to read his many articles and research projects. Larrin is a real metallurgist, not some old guy who wrote a book 50 years and really didn't know much about knife metallurgy at all.
 
B Bobbynickel ,
In short, steel typically comes in the "annealed" state. Its the softer state where metal is easier to work with and prepare to harden after generally formed. You wouldn't need to typically anneal a steel unless you happen to get it in another state of structure. I've only annealed a steel once, and that was after a heat treat mistake....it's kind of the "start over" state for blade making. That's very simpliefied but...Make sense?

My typical process:
1. Steel is purchased in an annealed state
2. steel is formed into a knife shape (i grind post heat treat for bevels typically)
3. steel is run through the Austentize cycle (gets very hard)
4. steel runs through two tempering cycles - steel dependent (loses some hardness but becomes far less brittle)
5. I finish all grinding and processing on the piece at this point

Hope that helps.


Best,
John
 
Thanks for the feedback, the steel is cold rolled and “annealed” I’m not sure about the hardness. My current setup is for stock removal, and I have the atlas forge. I will probably anneal the metal on my own because many reviewers said the metal was not annealed properly but otherwise fine.

The impression I’m getting is that annealing should only be done of the composition of the metal is bad, either due to a heat treatment mistake or mistake in the end of the supplier. Normalization is done just before the hardening process to relieve any internal stresses and standardize grain structure, it does not however alter the metallic compounds in the metal like annealing would. Which is to say if I do it correctly I should only need to anneal once at the start before I start to cut out the shape of the knife. Is my impression correct?

Thanks for all the help.
 
".... The impression I’m getting is that annealing should only be done of the composition of the metal is bad, either due to a heat treatment mistake or mistake in the end of the supplier. Normalization is done just before the hardening process to relieve any internal stresses and standardize grain structure, it does not however alter the metallic compounds in the metal like annealing would. Which is to say if I do it correctly I should only need to anneal once at the start before I start to cut out the shape of the knife. Is my impression correct?..."

No.

Read Larrin's chapters on normalizing and on annealing.
 
Just ignore all of this stuff until it is on an "as needs" basis! (lol)

Can you drill it? No need to anneal.

Did you forge it? Maybe get it too hot when forging? Trying to improve steel in an advanced manner (avoid this for now!) Normalize



That is a major oversimplification but there is only so much data to learn every day. Keep reading and making daily.

I have never needed to anneal anything in the 1000's of knives I have made. I do normalize a lot of simpler steels and everything I forge.
 
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