Heat treating AEB-L Slipjoint Spring Issue

JPSWorks

JPSWorks

Well-Known Member
The issue I am having is with the spring being a bit too soft after heat treating it. I should say tempering issue to be more specific. I did a bunch of searching on this and many other forums for some solid heat treating information for AEB-L steel. Unlike the CPM154 I've used before, which is as easy as downloading the PDF info from Crucible, I cannot locate anything written in stone. Alpha knife supply has tempering info but not up to the temps for a spring. I made a blade and spring yesterday, then heat treated it in my Paragon unit.

Blade and spring in ss foil.
Put in cold and ramped up to 1560 for 10 min to normalize
Then ramped up the 1950 for 15 min.
Quenched between 1" aluminum plates with compressed air and pressure.

Blade in oven at 410 for 2 hours two times
Spring back in Paragon after it cooled to 1000. Then heat tempered it at 1160 for 2 hours. Then I did it again at 1150 for 2 hours. I read somewhere where they did the spring 2 and sometimes 3 times. Most places I see it done only once.

The thing is that the spring still has good snap or tension on the blade but seems to lose it tension after I test it again and again. Has anyone here had good success with using AEB-L for a slip joint or lock back spring? What temp do you normally temper it at, and do you do it more than once? Would doing the second temper for 2 hours cause it to lose its spring and make it not bend back correctly? If so would you help me out with getting the spring temper dialed in? Unfortunately I do not have a Rockwell hardness tester.

Lastly, with stainless steel, can I heat treat the spring again and then temper it with success or is it just a lost cause and time to make another?

Thanks again everyone.

John
 
I was doing some additional reading and have found that people compared 13C26 to AEB-L because of a very similar composition. I did find on the following link a hardening process on the manufacture website. However it still does not include info above 700 deg for the tempering process.

http://www.smt.sandvik.com/en/produ...ening-programs/sandvik-13c26-piece-hardening/


I also found another post where someone did mention tempering to about 100 degrees lower than I did but it was for Sandvik/12C27, not AEB-L.

http://www.bladeforums.com/forums/showthread.php/751509-Sandvik-13C26-spring-temper
 
It appears that most people do not use AEB-l for slip joints.

I went ahead and did the heat treating process again for the spring and just took it out of the Paragon furnace after tempering it this time at 1000. I will give this a try to see how it works.
 
Drawing the spring for 2 hours at 1000 deg worked perfectly. Not sure what the actual RC is but it walks and talks fantastic now.
 
Thank You John, I had also found 1000 °F for slippie spring temper with stainless as adopted by makers on the forums. I suppose it does work also for AEB-L.
I would test some coupons and check for returning to true with a rise/fall indicator, or cuss for snapp!! ;) Basically is the spring will turn true, couple of times, after flexing way more then required for slipjoint work it'll likely be ok.
 
I'm not at all sure how many folks use AEB-L, but the Sandvik steels are being MUCH more popular as more folks use them. Take a look at this thread: http://knifedogs.com/showthread.php?34605-Sandvik-Blade-Steels

Maybe folks compare AEB-L to 13C26 because they have a similar chemical composition. Just because they have a similar chemical composition, there is no reason to think they are similar steels due to method of handling grain/carbide size. The Sandvik engineer I talked with said there was no reason for multi tempers, said 1 of the 2 hr temper cycles would all that's needed. Since they worked pretty hard to develop the special blade steels, I expect they have a good idea of best heat treatment required. They do not mention tempering for backsprings, but a well know slipjoint maker here on KD has provided backspring tempering info which is included in above link.

Ken H>
 
Don't discount the Bohler-Uddeholm AEB-L product Ken. They've been selling razor blade steel to Gillette since 1905 and have been making stainless razor steel longer than Sandvik. Their product is top notch and in some markets outsells providers of similar alloys. Given the competitive nature of the business and respect and history both companies enjoy, I'd be amazed if the products were not essentially of equal quality and performance.
 
I just finished my first slip joint folder tonight with the aeb-l spring and blade from my post above. I am very happy now with the walk and talk of the spring from this knife, after heat treating it again and tempering at 1000 degrees, and can hardly believe that I actually made it. Very proud of how it turned out. Going to take a bunch of pics tomorrow when I have decent lighting.
 
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JPSWorks said:
I just finished my first slip joint folder tonight with the aeb-l spring and blade from my post above. I am very happy now with the walk and talk of the spring from this knife, after heat treating it again and tempering at 1000 degrees, and can hardly believe that I actually made it. Very proud of how it turned out. Going to take a bunch of pics tomorrow when I have decent lighting.
Click to expand...

Boss Dog - we need a "like button" on this board. :)
 
JP - isn't it a GREAT feeling when your first slipjoint actually does the "walk 'n talk" with backspring flush in all 3 positions.

I will 2nd (and 3rd) the idea of a "Like" button - felt that many times in the past.

Rob, I agree with you the AEB-L is most likely a very good steel - I've just ordered a couple sticks of it for paring type knifes. I've heard that most of razor steel is now Sandvik with their 13C27 alloy. I'm sure razors are using both AEB-L and 13C26. It would be interesting to know what percentage of razors have which alloy?

Ken H>
 
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KenH said:
JP - isn't it a GREAT feeling when your first slipjoint actually does the "walk 'n talk" with backspring flush in all 3 positions.

I will 2nd (and 3rd) the idea of a "Like" button - felt that many times in the past.

Rob, I agree with you the AEB-L is most likely a very good steel - I've just ordered a couple sticks of it for paring type knifes. I've heard that most of razor steel is now Sandvik with their 12C26 alloy. I'm sure razors are using both AEB-L and 13C26. It would be interesting to know what percentage of razors have which alloy?

Ken H>
Click to expand...
It is a great feeling indeed.
 
Congratulations for your first Walkandtalk!!!! I have also finished my very first slippie and i'm so happy with the result. Mine is in C70 (aisi 1070), the next will be in sandvik 14c28n, a steel i tested before with EXTREMELY satisfactory results...it is of the super-keen-edge-no-carbide league, so to speak ;) Really, it would be impossible to distinguish from a carbon steel apart the fact it doesn't stain.
To stick with carbon the way to go is 1.2519!!!
click-click-click
 
stezann said:
Congratulations for your first Walkandtalk!!!! I have also finished my very first slippie and i'm so happy with the result. Mine is in C70 (aisi 1070), the next will be in sandvik 14c28n, a steel i tested before with EXTREMELY satisfactory results...it is of the super-keen-edge-no-carbide league, so to speak ;) Really, it would be impossible to distinguish from a carbon steel apart the fact it doesn't stain.
To stick with carbon the way to go is 1.2519!!!
click-click-click
Click to expand...
Stezann,

Thank you. It feels good to finish it and have it work well too.

If you haven't already posted a picture of your slip joint yet, create a new post and show us some pics of that knife. I would like to see it and I'm sure others would as well.

John
 
Eh eh, i'm a little shy ;) Seriously, how do i post pictures on the forum? Can anyone please teach me how to do?
 
The 14c28n is not cooperating :( The blade it's fine but i'm having hard time with the spring!!!
let me explain:
I do have temp control in the forge and can run it steady at the hot temperatures, so i can and i did harden carbon and stainless, but can not draw spring temper with it, because can't stand too low temperatures evenly.
Same thing for the tempering oven, wich can't run hotter than 250 °C which is too low for a stainless spring temper.
With carbon steel i add a quick blue draw (degreased steel) with the torch after a through 250 °C temper in the oven and call it good....indeed it was.
But with the stainless spring it doesn't work...the spring had lost it's return-to-true feature (i went past blue, almost to grey)(degreased steel).
this weekend i will try again, but i need some emergency protocol...if everything fails i will put a carbon spring on my stainless knife, but i would consider this option as a last resort.
Any ideas friends?

Stefano
 
Stefano, your oven won't hold 1,000F or 1100F? That does make it hard. I've not had any problems with 14C28N springs, and I know Calvin (real expert there) uses 14C28N for backsprings with success in slipjoints.

I have a feeling a carbon backspring would work just great - part inside the knife would be the only part I'd think a possible corrosion would show up.

Ken H>
 
Thanks Ken, the problem is indeed i can't ensure controlled 1000-1100°F for extend periods :(
By the way, (because i'm unequipped AND stubborn) when you had tempered the ss spring which color came out of the oven? I mean, i don't require the same strict control/performance as for a blade requirement (that should not be approximated!!!), but i only need that little piece of steel not to break nor loosing enough strenght to act as a decent spring ;)
John, i don't want to hyjack your thread, but i'm little desperate :34:
 
stezann said:
.... mean, i don't require the same strict control/performance as for a blade requirement (that should not be approximated!!!), but i only need that little piece of steel not to break nor loosing enough strenght to act as a decent spring ;)
John, i don't want to hyjack your thread, but i'm little desperate :34:
Click to expand...


No worries at all.

Regarding the tempering of a spring. I believe that the control over the temperature, and the proper time that the steel is held at that temperature is just as crucial as the tempering process of the blade itself(For Stainless). My experience is with stainless steel, though I assume this translates well to carbon steel too.

John
 
Stefano, your question about color for tempering SS spring. I don't think with SS you can really follow a color very well. Remember, at 1100F you're almost to the "glowing dull red" color of steel. If you have no way to temper SS at 1,000 to 1100F, then by all means, use a carbon steel for backspring. I wonder if the carbon steel will take a patina over time in the backspring? Perhaps somebody can comment on that?

Ken H>
 
Today and tomorrow i will have access to my shop and will do some new trial.
the carbon spring is ready so i am more comfortable trying messing with the stainless one
I will try to tune the forge and persuade her to run 1000-1100 °F.
I hope it will work, because i am sure that the carbon spring will turn grey within a few years and it will show very well
In contrast with liners and blade.
In that case this will be my last SS knife, at least until i get a kiln.
Anyway i will keep you informed of the results.
Thanks for the help guys!! ☺
 
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