Heat treat question

Joined
Apr 25, 2022
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Ok, I have a heat treating question. I am doing some 1/8” stock and it turns out pretty warpy when I try to heat treat it, so I have been doing something sort of like a plate quench, but instead of aluminum I use wood. I do an oil quench first, so that’s not when it’s supposed to harden. After I oil quench it, I clamp it between two blocks and wait for it to cool between them so it’s straight before I temper it. Now my question is how much should I take off of the temper to account for the slightly slowed cooling between the wood? After 10-15 minutes it is still very slightly warm, so I imagine this would be an issue if I did a normal tempering cycle on it. I’ll check after this one is finished to see if it still skates a file, so if it does then I may just take a few minutes off the temper. If it doesn’t, then I may have to re-harden.😬 unfortunately this is a situation where I thought of an okay solution to the first problem, but I didn’t really think about if it would cause other problems. I think in an ideal situation I would go for metal plates, but I didn’t have anything on hand that would work for that. If I did, then I would probably just quench it then temper between the plates, so that would be no problem, but at this point I don’t have that. Any advice on this would be greatly appreciated! Thanks!
 
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Apr 25, 2022
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Update: I took the knife out when It was cooled and it still totally skates a file, so I should be mostly fine. I would still appreciate any tips, though! I don’t think this needs to be a permanent fix!😂
 
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Aug 5, 2001
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3,300
Will, you'll probably get faster and better answers posting your question in the "Shop Talk - BladeSmith Questions and Answers" sub-forum. :)

 
Joined
Apr 25, 2022
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I have been having problems with steel warping during heat treat, so my solution was to clamp the knife between two blocks of wood after quenching so it will be straight after the quench. I would use metal and temper it between two pieces, but Indont have any pieces that would work. My issue is, after about 10-15 minutes I’ll take it out of the wood, but it is still slightly warm, so I think this may affect the temper. Does anyone have any advice on a better way to do/avoid this? Also, after taking it from the wood, it will still skate a file, so that’s good, but this is definitely not an ideal solution. I’d love to hear any comments on this. Thanks!
 

Bunker Hill Blades

Joseph B
Knifemaker / Craftsman / Service Provider
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Dec 9, 2021
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What are you using to HT your blades? How are you quenching? What steel(s)? It could also be uneven grinds.
My favorite way to straighten a blade is surface peening. If it’s bad, then I’ll let it cool, temper then use a vise and a torch to get it mostly there, then switch to peening.
 
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Apr 25, 2022
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Just a little propane forge and vegetable oil to do some AEBL. It is very possible that it is the uneven grinds. Good idea, I’ll try that if my next one does the same thing! Do you peen the top or valley of the bend? Also, does the torch usually affect the heat treat?
 
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Apr 25, 2022
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if it's AEBL why not just plate quench it? that'll help keep it straight
I’ve actually been looking into plate quenching for that very reason, but plates the size I would need are a bit expensive, so I’ve been looking around for some scrap pieces. Do you have any info on plate quenching though? I’d love to learn more, but I don’t really know where to look.
 
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May 1, 2019
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Sorry, can't help. I don't work with stainless, it's too complex for my setup and I just don't like it.
I assume you know about knife steel nerds? lots of good info there.
 
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Apr 25, 2022
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Sorry, can't help. I don't work with stainless, it's too complex for my setup and I just don't like it.
I assume you know about knife steel nerds? lots of good info there.
Ah gotcha. I think I’ve heard about it. I’ll go check it out for more info. Thanks!
 

Bunker Hill Blades

Joseph B
Knifemaker / Craftsman / Service Provider
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Dec 9, 2021
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Heat treating in a gas forge is not the best, but it can be done with OK results with simple carbon steels, unfortunately you really cannot HT stainless in a forge. With that aside AEB-L is a steel that likes to warp.
Peen the inside of the warp/bend/valley, the idea is that your pushing out the metal with little indents, causing the steel to expand on that side. Heating the steel with a torch will NOT effect it, as long as you don’t heat it above the temperature you used for tempering.
Like A Alex Topfer said, you need to check out http://knifesteelnerds.com/ it is one of the best places for HT info and knife making info in general.

Best of luck,
Joseph
 
Joined
Apr 25, 2022
Messages
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Heat treating in a gas forge is not the best, but it can be done with OK results with simple carbon steels, unfortunately you really cannot HT stainless in a forge. With that aside AEB-L is a steel that likes to warp.
Peen the inside of the warp/bend/valley, the idea is that your pushing out the metal with little indents, causing the steel to expand on that side. Heating the steel with a torch will NOT effect it, as long as you don’t heat it above the temperature you used for tempering.
Like A Alex Topfer said, you need to check out http://knifesteelnerds.com/ it is one of the best places for HT info and knife making info in general.

Best of luck,
Joseph
Thanks for all that advice! If a forge is not the best for AEBL, what would you recommend? Is there something else I can do?
 

Bunker Hill Blades

Joseph B
Knifemaker / Craftsman / Service Provider
Joined
Dec 9, 2021
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If you don’t have access to a heat treating oven, and want to make stainless knives then I would recommend sending them out, https://www.jarodtodd.com/ does a really nice job, you’ll just have a bit of a wait.
If you want to heat treat yourself then use simple carbon steels like 8670, 80crv2, 1080/1084, or 15n20
There are a lot of good options!
I highly recommend you start by reading this article,
 
Joined
Apr 25, 2022
Messages
100
If you don’t have access to a heat treating oven, and want to make stainless knives then I would recommend sending them out, https://www.jarodtodd.com/ does a really nice job, you’ll just have a bit of a wait.
If you want to heat treat yourself then use simple carbon steels like 8670, 80crv2, 1080/1084, or 15n20
There are a lot of good options!
I highly recommend you start by reading this article,
That’s some great information! Thank you very much!
 

PMQ

Joined
Feb 17, 2020
Messages
131
forge is not the best for AEBL,
When you start adding alloys, in this case chromium for stainless steel, the austenizing temperature goes up from 1500F to 2000-2050F. With simple steel, you can eyeball 1500F or check with the magnet and get good results, but for 2000F, you'll need a thermalcouple to check the temp and someway to hold it, and forges are not easy to check and control the temp.
 
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