Question about tempering

TomoGato

TomoGato

Joined
Sep 6, 2021
Messages
10
Hi There,

I was having trouble finding a good answer on this, my apologies if it is common knowledge, but I had a question regarding tempering after quench. I have seen a lot of videos where smiths talk about going straight into temper after quench, without letting the blade drop below a certain temperature, about 120 degrees F.

What is the reason for maintaining that temperature after quench? I have been washing off my knife after quench to get all the oil off, since I temper in my kitchen oven, and try to get as much oil off as possible, but that is decreasing the temp below 120. Are there any negative impacts by doing this?

Thank you for your time!
 
TomoGato said:
Hi There,

I was having trouble finding a good answer on this, my apologies if it is common knowledge, but I had a question regarding tempering after quench. I have seen a lot of videos where smiths talk about going straight into temper after quench, without letting the blade drop below a certain temperature, about 120 degrees F.

What is the reason for maintaining that temperature after quench? I have been washing off my knife after quench to get all the oil off, since I temper in my kitchen oven, and try to get as much oil off as possible, but that is decreasing the temp below 120. Are there any negative impacts by doing this?

Thank you for your time!
Click to expand...


Read about tempering at
Knifesteelnerds.com

Search "tempering" "quenching"
 
Maybe an issue with some complex stainless steels. Nothing to worry about at all with simple carbon steels your tempering in your kitchen oven. It's best to get them in the temper as soon as you can aftequenching. Within an hour is just fine. Probably within a day wouldn't make any measurable difference.
 
nmbarta said:
Maybe an issue with some complex stainless steels. Nothing to worry about at all with simple carbon steels your tempering in your kitchen oven. It's best to get them in the temper as soon as you can aftequenching. Within an hour is just fine. Probably within a day wouldn't make any measurable difference.
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thank you!! continued looking and it seems like it has to do with different steel compositions cooling and a race to release the stress. Since I'm using mono-steel, seems negligible, but best practice
 
You'll find that many, including myself, go straight from the oil quench into the plates. ( mine are 1.25" aluminum plates set up in the vise). I quench in parks 50 for about 9 seconds and then finish in the plates. Blades come out perfectly straight and fully hardened. Then they go into the temper, typically within 5-10 minutes. I work mostly with 15n20, but do use some 1084 and some 80crv2. The plates are well worth your time. I got mine frome a local fab shop for free....it was just scrap to them.
 
nmbarta said:
You'll find that many, including myself, go straight from the oil quench into the plates. ( mine are 1.25" aluminum plates set up in the vise). I quench in parks 50 for about 9 seconds and then finish in the plates. Blades come out perfectly straight and fully hardened. Then they go into the temper, typically within 5-10 minutes. I work mostly with 15n20, but do use some 1084 and some 80crv2. The plates are well worth your time. I got mine frome a local fab shop for free....it was just scrap to them.
Click to expand...
ooof i need to look into oils, that's my next step, ive been using peanut oil lol, guess its time to research
 
AEBL, 15N20, O1 and 1084, but i would say the vast majority has been AEBL, but the more i learn about it the more i think im not getting anywhere near its potential. As a simpleton though, ive been pleased with the outcomes ^_^
 
TomoGato said:
AEBL, 15N20, O1 and 1084, but i would say the vast majority has been AEBL, but the more i learn about it the more i think im not getting anywhere near its potential. As a simpleton though, ive been pleased with the outcomes ^_^
Click to expand...
Sorry, I’m just a consumer - can’t help with tempering, but I’d love to see pics of your work.
 
If your pleased, your doing something right. Aebl does require some advanced ht procedures to get it right. If your using a forge...1084 is Your best friend. 15n20 works, but the soak times can't be done right in a forge. They can be done good enough to get a functional blade.
Parks 50 is what you need for a good quench, but if can't afford it....canola oil pre heated to 120-130 degrees will harden 1084 decently enough to get a good blade. Funny that canola works for a quenchant .....that stuff ain't food!!!!
 
nmbarta said:
If your pleased, your doing something right. Aebl does require some advanced ht procedures to get it right. If your using a forge...1084 is Your best friend. 15n20 works, but the soak times can't be done right in a forge. They can be done good enough to get a functional blade.
Parks 50 is what you need for a good quench, but if can't afford it....canola oil pre heated to 120-130 degrees will harden 1084 decently enough to get a good blade. Funny that canola works for a quenchant .....that stuff ain't food!!!!
Click to expand...
Definitely checking out Parks 50 and aluminum plates, thanks for the advice!! Got stuck on some earlier hurdles time to step it up :)
 
TomoGato said:
Definitely checking out Parks 50 and aluminum plates, thanks for the advice!! Got stuck on some earlier hurdles time to step it up :)
Click to expand...
gotta have the right tools to do it right. It's not too difficult to shape a piece of steel like a knife, heat it up and dunk it in some sort of oil, sharpen it up a bit and have tool that will cut stuff. nothing wrong with that...I built a few of those, then quickly realized if I was going to spend my time on it, I want it right. spending hours on knife that gets beat by a wal mart special will either make you step up or game.....or quit.
 
nmbarta said:
gotta have the right tools to do it right. It's not too difficult to shape a piece of steel like a knife, heat it up and dunk it in some sort of oil, sharpen it up a bit and have tool that will cut stuff. nothing wrong with that...I built a few of those, then quickly realized if I was going to spend my time on it, I want it right. spending hours on knife that gets beat by a wal mart special will either make you step up or game.....or quit.
Click to expand...
can't wait to reach that point! other than a file test, how can you really gauge the quality of the heat treat
 
many ways, file test really only tells you it's hard. Depending on what you do with your steel ( forge to shape, or stock removal....I do both depending on what I'm doing) you may need to normalize your steel. (if your forge, and depending on where you bought it..which determines what condition it was in when you started) After that, you need to thermal cycle it to get your grain structure refined. You can tell how your doing by making a few test coupons and take them through your process. After you harden them, put them in a vice and break them with a hammer ( be careful, the pieces that break off will leave very fast....broke out my car window doing this and it was 20 feet away) Then examine your grain structure....it should look like powdered sugar....not like table salt. If you have fine grain, and it's hard enough to skate a file, and break clean in a vise without any bending.....you likely have a pretty good piece of steel. Then.....you can temper it and sharpen it. The brass rod test is a decent way to tell if your edge is tough and hard. Don't forget that you will need to remove all of the decarb (thin layer of steel that looses it's carbon during the forging and ht process....it will not harden) So basically, if it breaks clean, it's fine grained, it skates a file, and passes the brass rod test.....you have piece of steel that will make a good knife. It may not be 100 percent perfect....but at that point...it's going to hang with or outperform anything you can buy unless you plan on spending big money. I don't mess around anymore and get all of my steel from AKS, it comes ready to austenitize and it's consistent. You have to know what your starting with.
 
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