Re-heat treatment the O1???

[U.C.O.K.]

Hello guys

I made a blade from O1 steel last year. It already hardened but not drawned yet, it just sits in the canola oil for months.

I want to know: could I repeat all the process of heat treatment from the beginning? Thanks in advance.

Frids

 

[Keith_H]

sure, I don't see why not. Some people triple quench O1 anyway.

 

[U.C.O.K.]

Thank you Keith. Good to know that.

Frids

 

[AcridSaint]

If the blade sat that long without tempering, you might have to worry about micro-fractures.

 

[Kevin R. Cashen]

Hello guys

I made a blade from O1 steel last year. It already hardened but not drawned yet, it just sits in the canola oil for months.

I want to know: could I repeat all the process of heat treatment from the beginning? Thanks in advance.

Frids

What are your tools and equipment now? What were they then? Why do you want a do-over instead of proceeding to the long overdue tempering?

If you nailed the hardening properly, I wouldn't trust an O-1 blade that went that long without tempering, so I would repeat the process, but the entire process with a new piece of steel.

However if the blade is still in good shape then that would indicate that the initial hardening was rather unsatisfactory anyhow and you could give it another shot. Expect a little more chance of distortion and the need to remove a little more of the skin due to the reheat.

As Keith pointed out, some folks triple quench O-1, but then some folks also drink strychnine and handle snakes in church... personally I would need some real good reasons to follow suit before dropping my hymnal for the jar or a rattler.

 

[U.C.O.K.]

Kevin, the knife is still in the good shape but your opinion do frightened me. Any consideration not to finish this blade?

Frids

 

[Keith_H]

I don't understand how sitting without tempering can harm it, if it is not used, then isn't it like having a file around?

 

[silver_pilate]

I believe even files are tempered to some extent, and they're not generally made of O-1.

I would think that leaving a great deal of stress in a blade (i.e. untempered martensite) would eventually expose weakness in the steel (i.e. micro fractures).

--nathan

 

[Kevin R. Cashen]

Any steel above .6% carbon will benefit from tempering (so will the stuff below .6% but it is not as critical), and the greater the carbon content and alloying to promote hardening, the more ciritical it will become. Files would indeed be tempered just not enougn to drop the hardness significantly. I wouldn't expect any steel above .8% carbon that was truly fully hardened to survive the stress of going with no tempering at all, if it doesn't warp or outright visibly crack, I would expect there to be previsouly mentioned micro-fracturing.

This is one of the reasons behind my questions of U.C.O.K's tooling, if the heat source was simple enough to limit the soak time to seconds and the heat was kept low, proper solution may not have been reached, thus total hardness my not have been enough to stress the steel over time. However, if that O-1 had been heated from 1475F to 1500F for 8 to 10 minutes and then oil quenched to ambient, I wouldn't trust it for more than a few minutes without a temper.

 

[JoshEarl]

As Keith pointed out, some folks triple quench O-1, but then some folks also drink strychnine and handle snakes in church... personally I would need some real good reasons to follow suit before dropping my hymnal for the jar or a rattler.

Kevin,

If I could figure out how to add a sig line, this quote would be in it.

Josh

 

[Leu Custom]

Kevin,

If I could figure out how to add a sig line, this quote would be in it.

Josh

Easy! Pay the membership fee!

 

[Troop]

I don't know why (wish I did), but it seems like the more alloys a steel has, the more it "dislikes" being quenched more than once.
- Mitch

 

[Dan Gray]

if you have a mind to junk it anyway
I'd temper it and do some testing on it to see what you have there now..
setting for the day is one thing maybe, a year is priceless

I haven't left one for that long but have left them for a while with no problems of breaking later. I made my first o1 blade in 1974 the 2nd one I made was in the same year and I still use it hunting every year..back then I wouldn't have given a thought to leaving them a day or two.. today I'll temper the same day at least or I'm appt to forget to do it all together
I've done that one once that I can remember of..
if you have only made one or two blades I know it can be hard to just junk it.. play with it.. and learn from it..
just my 2cents

 

[Kevin R. Cashen]

I don't know why (wish I did), but it seems like the more alloys a steel has, the more it "dislikes" being quenched more than once.
- Mitch

Perhaps in terms of distortion, but with a little alloying it will show differences a bit more. If your method of heating falls short of what is necesarry each heat and quench will pull a little bit more into solution and then lock it there so by the third cycle you could be approaching what an accurate and well controlled austenization could have done in one heat. Simpler steels will not show as much of a differnece because they will go into proper solution easier.

As I previosly stated, this is a bit of a catch 22. If the blade was hardened properly it will most likely not have faired well without a temper, if the initial hardening was not so great it could be all right but may require a proper hardening this time.

 

[Troop]

Perhaps in terms of distortion, but with a little alloying it will show differences a bit more. If your method of heating falls short of what is necesarry each heat and quench will pull a little bit more into solution and then lock it there so by the third cycle you could be approaching what an accurate and well controlled austenization could have done in one heat. Simpler steels will not show as much of a differnece because they will go into proper solution easier.

As I previosly stated, this is a bit of a catch 22. If the blade was hardened properly it will most likely not have faired well without a temper, if the initial hardening was not so great it could be all right but may require a proper hardening this time.

Kevin, that's not exactly what I'm talking about. What I'm asking about is that why does alloy steel, i.e., O-1, with a proper austentizing, do poorly with more than one quench.
Obviously, there's no need to do multiple quenchings if the first one is done correctly, right? I've observed with alloyed steel, namely O-1, that it doesn't do well with more than one proper quenching.
I ruined a very thin blade of O-1 that I forged out of 5/8 round stock; got a real bad warp in it during the quench. I put it in the vice too late, to try and straighten it. So, I brought it back up to heat, and quenched it again. Put it in the vice; still no good. I quenched it for the third time, put it in the vice, and finally got it straight. I tempered it like I usually do, at 425 2X for 2 hours each time.
The blade is shot; doesn't hold an edge. I'm thinking that, obviously, it was too many heats for that thin blade. But, it got me wondering about alloys and multiple quenching.
I've heard about multiple quenchings for O-1, but I just can't see it. Now, 5160 is a different story; many people do it, including me, and the multiple quenchings work fine for that steel.
So why not O-1?

Thanks for your responses.
- Mitch

 

[Dan Gray]

you are making me wonder if now only on 3rd quench you were able to straiten the blade out but now it's not hard.. did you check if you got it hard that time?

could it be,, you didn't nail the quench on the 3rd time around ?

or did you over heat it three times burning out your carbon ?

heat treating 01 3 times shouldn't hurt it but heat treating it incorrectly on the 3rd time can un-due what you did the last time treated for sure, we know that..
try quenching again making sure it's hard if you didn't on that time befor
just a thought...

 

[Troop]

you are making me wonder if now only on 3rd quench you were able to straiten the blade out but now it's not hard.. did you check if you got it hard that time?

could it be,, you didn't nail the quench on the 3rd time around ?

or did you over heat it three times burning out your carbon ?

heat treating 01 3 times shouldn't hurt it but heat treating it incorrectly on the 3rd time can un-due what you did the last time treated for sure, we know that..
try quenching again making sure it's hard if you didn't on that time befor
just a thought...

Dan, I think the matter was just simply too much heat for that thin blade. Each "quenching heat" for this particular blade was at least to the austenizing temp for the O-1. I did a 10-min soak prior to each quench.
Too much heat for that thin blade. But, it got me thinking about multiple quenches. Works for 5160...wondering it if works for O-1? I've never multiple quenched O-1 before, and I don't like the results. Of course, like I said, I could have just fried the blade, which, at that point, wouldn't prove or disprove anything about multiple quenchings.
- Thanks
P.S. It took me three times to straighten the blade in the vice because of too much time fumbling around on the previous attempts.

 

[Dan Gray]

wondering now ?
did you check the spine of the blade to see if it was soft as the edge also? I'm sure you wouldn't have burned out the carbon from the spine where it's thicker, or is the whole blade that thin? if it was soft also, then you have another issue other then thinness and burn out
would be my thought..

if my o1 blades are to thin they normally ripple at the edge if they don't ripple they are thick enough at .030 or more depending the use of the blade in it's new life is good for mine.. then grind any dead skin off.

 

[U.C.O.K.]

Kevin... my tools is an archaic type of heat treatment. I use charcoal to heat the blade that I put inside a pipe and wait till the red glow comes, test it with magnet, put back for 5 second and put it in canola oil.

I will take a picture of the knife and the tool I use to heat treat in these few days to come to wait for my camera. But I already did a file test on the blade and it's hard enough to make the file slide away.

 

[Troop]

wondering now ?
did you check the spine of the blade to see if it was soft as the edge also? I'm sure you wouldn't have burned out the carbon from the spine where it's thicker, or is the whole blade that thin? if it was soft also, then you have another issue other then thinness and burn out
would be my thought..

if my o1 blades are to thin they normally ripple at the edge if they don't ripple they are thick enough at .030 or more depending the use of the blade in it's new life is good for mine.. then grind any dead skin off.

Hmmm...this has got me thinkin'. I've never had any trouble with O-1 before. I'm shocked that the blade doesn't hold an edge. (Kinda hurts my pride.)
I'm going to have to look more deeply into this matter. I know O-1 isn't A2, which I've been working a lot with lately, but still; that O-1 is just not holding it's edge. :grumpy: The spine is approx. .07 thick.
Thanks for the advice.
Wait a minute....I just filed the corner of the spine off with a chainsaw file; the whole blade is soft!