# Forge built - Time to heat treat



## Seffers93 (Sep 3, 2020)

Hey guys!

Got the forge set up. Ready to heat treat the steel! So the plan is to heat the steel to non-magnetic and then go just a shade beyond that, and quench immediately in pre-heated 130°F canola oil. After I make sure it skates a file, I’ll throw it in the toaster oven at 400°F for two hours. I threw in an oven thermometer and made sure 400° is actually 400° so it should be good to go.

Anything I should do differently? Or any suggestions? Not sure if I should normalize the steel by heating and then cooling to room temp a few times. 

- Seth


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## Caleb Cox (Sep 3, 2020)

Very nice! Have fun and be safe!


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## applepieforbreakfast (Sep 3, 2020)

I had good luck with 1084 by watching for decalescence, and then quenching. It kinda looks like a shadowy line moving across the steel, from thinnest to thickest sections. Probably best seen in a fairly dim room.

Decalescence


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## Tim Rowland (Sep 3, 2020)

If you have a pyrometer it can help.
1084 does well at an austentizing temp of 1425-1450F
If perfectly hardedned it should be about 65rc
If you temper at 400F you are going to be at around 60-61rc
375F will get you around 62-63rc


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## Seffers93 (Sep 3, 2020)

applepieforbreakfast said:


> I had good luck with 1084 by watching for decalescence, and then quenching. It kinda looks like a shadowy line moving across the steel, from thinnest to thickest sections. Probably best seen in a fairly dim room.
> 
> Decalescence



Thanks for the tip! I’ll look into that!


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## Seffers93 (Sep 3, 2020)

Tim Rowland said:


> If you have a pyrometer it can help.
> 1084 does well at an austentizing temp of 1425-1450F
> If perfectly hardedned it should be about 65rc
> If you temper at 400F you are going to be at around 60-61rc
> 375F will get you around 62-63rc



Good to know! I think I’ll go for 375 then.


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## Kippington (Sep 3, 2020)

Good luck!
Some notes:

Take this lightly because everyone sees color differently, but if you do it in a dim room - bright red is too cold, bright orange is too hot. Somewhere between the two is good. Some people describe it as a salmon color, which I find to be pretty accurate.
Depending on your heat source, decalescence can be very difficult to spot. I've personally never relied on seeing it. If you reach bright orange before you see decalescence, it means you've already missed it.
If you choose to use either decalescence or magnetism to find the sweet spot, then don't heat the blade up as quickly as you can. The faster you increase the temperature of the steel, the more inaccurate these methods get. Creeping up to temperature also helps act as a "soak" time for the steel, giving carbides the time to go into solution.
Have your heat source as carburising as possible. If you get flaky forge scale forming on the surface while heating it up and/or getting it to the oil, it can block the quench.
If you want you can temper even lower (e.g. 340*°*F) and it will still be good, especially if you were slightly under-heated before the quench.
Make sure you temper twice, in case the first temper converts retained austenite into new martensite.
Getting a simple tool steel to skate a file is actually quite easy. Much easier than hitting the perfect quench temp, which is near impossible by eye. Don't stress too much.
One of the most difficult things you'll discover is getting the entire blade heated up evenly. You really can't be in a bright room if you want to do this with any accuracy. The longer the blade and the smaller the heat source, the more difficult this becomes.



Seffers93 said:


> Not sure if I should normalize the steel by heating and then cooling to room temp a few times.



Did you forge the blade or was it stock removal?
Is it 1084?


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## Seffers93 (Sep 4, 2020)

Kippington said:


> Good luck!
> Some notes:
> 
> Take this lightly because everyone sees color differently, but if you do it in a dim room - bright red is too cold, bright orange is too hot. Somewhere between the two is good. Some people describe it as a salmon color, which I find to be pretty accurate.
> ...



Those are awesome tips Kippington! Thank you!! I’m going to re-read them tomorrow and jot them down somewhere! I ended up going with magnetism to find that sweet spot. It took a bit to get up that high so I don’t think I rushed it. After it became demagnetized, I left it in for just another minute before quenching. It seemed to be heated pretty evenly. But I’m also just going by color. And I could definitely be wrong as this was my first time! I’m actually just going out now to take it out of its second tempering cycle. I didn’t see your post in time to take your suggestions into account, but I will next time.

And it was 1084 stock removal.

- Seth


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## RDalman (Sep 4, 2020)

Really good tips from kip. To check yourself and your forge/environment and practice you can use small strips of the steel to quench, file check and break to see what the grain looks like, and from there get a good idea of what it should look like in your eyes and forge.


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## Kippington (Sep 4, 2020)

Seffers93 said:


> I ended up going with magnetism to find that sweet spot.


I was about to type some more detailed stuff about using magnetism as an indicator, but discovered @Larrin has already done it...








Can You Trust Your Magnet During Heat Treating? - Knife Steel Nerds


Many knifemakers heat treat with nothing but a forge and a magnet. Is that reliable? What does it mean when the steel is no longer magnetic?




knifesteelnerds.com




So judging by the pictures of your forge and knowing what the steel is (1084), you likely hit full non-magnetic (in this case, Ac3) at around 1380-1400° F, with a targeted quench temp of around 100° higher than that to help negate a soak time.

Luckily though, you picked a very good steel to begin with - So even if you didn't understand a word of what Larrin said or any of the science, you'd still likely end up with a blade that could pass a file test.

Congrats!


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## Seffers93 (Sep 4, 2020)

Kippington said:


> I was about to type some more detailed stuff about using magnetism as an indicator, but discovered @Larrin has already done it...
> 
> 
> 
> ...



Thanks for linking that article! That's a lot to take in for someone who has no previous knowledge on this topic lol. But I hope to better understand it the more I work and study.


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## Seffers93 (Sep 4, 2020)

The blade came out of the second tempering cycle with no warping! I was pleasantly surprised. Time to get back on the grinder and then get a handle on this thing! 

Also, during my lunch break today, I'm going to cut out a couple more rough profiles! I'm having way too much fun with this


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