O1, again

Chiro75

Chiro75

Joined
Feb 4, 1999
Messages
5,786
Here's an update on my O1 problem. Cut a few small pieces, brought to non-magnetic, quenched in oil, harder than hell, file can't bite.

Ground large Wharnie, did the same, file doesn't bite. Tempered at 385, cleaned up, etched, and nothing. No temperline. Pressed the crap out of it on brass rod, no deformation of edge, no chipping. Chopped some woood, seems okay, too. This one I clay coated. Is it possible it through-hardened despite the clay? File doesn't seem to bite too much along the edge or most of the spine. What do you think?
 
O1 is a medium hardening steel. While sure there are those that can acheive a good temper line my choice for that would be a shallow hardening steel, such as 10XX is.

RL
 
As far as knife steels go it's pretty deep hardening. It's not a good choice for creating a hamon.

I'm sure somone will come and post an edge quenched or torch hardened blade with a transition zone...but that's not what you were shooting for was it? :)

-Nick-
 
Steve - Listen to those who know.O-1 is not the best steel for a temper line.Sure it can be done,but apparently not by you.(just razzing you)Use 1095 or better 1080.
 
Like Nick said, O1 is designed to get really hard, really easily. It's not the best choice for a visible hardening line.
 
Attached is the TTT curve for O1. That is about all the help I can give you. Personally I have never had a problem with heat treating O1. It is a heck of a lot easier to HT O1 than 1095, but then again I don't do any hamon work.

Other than the TTT curve, I can only recommend that you spend some time learning the fundamentals of heat treating and doing a DOE on O1 until you get the results you are looking for. Not every question can be answered concisely. Sometimes it takes you experimenting for days, weeks, or months until you get the results you are looking for.

Knife making is not a craft of instant answers, but more the art of trial and error.

O1_TTT1a.jpg
 
I think there's a minor error in the TTT chart, there's 2 "800"'s on the temp side, I'm pretty sure the second one should be 600.
 
Please notice the nose of the cone, it has 10 seconds to get past it and that means that the blade that got hot enough to harden, will harden, even under the clay if it cools in 10 seconds or less.
I think that to get a temper line, you would need to heat the edge and then edge quench to keep the upper part of the blade from getting hard. At least it looks like it to me.
 
AwP - Mine shows 600.It is close to the "0" and looks like an "8".
Raker is correct.One of the easy things about O-1 is its ability to harden throughout.
 
I think Nick and Ray have it right. I have obtained a reasonably nice hamon on O1 blades using a torch and heated edge only. No hosting here or I would post a pic.
 
Fox said:
I have obtained a reasonably nice hamon on O1 blades using a torch and heated edge only.
Click to expand...

Hamon or hardening (transition) line?? There is a difference.
 
Fitzo, you may be correct, but I tend to use the terms interchangeably since I am not into Japanese swords and the intracacies of the hamon definition and the semantics regarding the same. A quick search of these forums shows that the terms are used interchangeably on a very regular basis, hence my previous comments. I have never been able to find a good definition that differentiates between the terms "hamon" and "transition zone" without delving into the nuances of the Japanese language and the associated descriptions. In fact, a quick Google search turns up the following from several Japanese sword and custom knife sites, which makes it even more difficult to differentiate between the two terms:

Hamon: The pattern of the hardened, martensite steel as it shows on the side of the blade including the transition zone habuchi to the softer pearlite steel.

Hamon: The "line" or visual characteristic typical of Japanese blades caused by the use of differential hardening.

Hamon: The hardening pattern on the blade.

Hamon: Is the line demarcating the transition between the hardened and unhardened zones of the blade.

I am certainly open to a good definition of the terms and their differences, but have never been able to find one and the available information does not seem to help.
 
Fox, I *think* the differentiation is because a hamon was patterned, articulated for a planned effect, an artistic use of a physical characteristic, brought out via polishing, whereas a transition line as in O-1 cannot really be manipulated because of the effects of the chromium. Plus, it's visibility is the effect of etching. It is very difficult to get anything but a straight line in steels like 52100 and O-1, though I have seen it done on "Little Hen's" O-1 knives IIRC.

Don't get me wrong, I am not knocking the transition line, I like them. I do think, though, that we misuse the term. I thought it might be an interesting point of discussion.

I am certainly not trying to create any dispute with you.... :)

Hopefully some others will have some input.
 
I agree that it typically boils down to semantics.

However, as someone that's spent a lot of blood, sweat, and tears studying and applying methods to create a hamon... it's a bit of a jab in the eye when someone shows you an edge quenched blade and says, "look at the beautiful hamon."

It's not all that hard to rock a blade back and forth on a depth plate in your quench tank.

Doing the proper thermal cycles, applying clay, doing everything right in the austenitizing, AND THEN doing at least a decent polish to get the hamon to pop... is lots of work and lots of opportunities for failure.

I've offended some folks with this line of thought in the past, but my recommendation to them- Would be to do a couple years worth of clay-hardening and tell me if you think edge quenching or torch hardening is the same :D

-Nick-

BTW- I am NOT knocking edge quenching. Just pointing out some differences as I see them. One guy here that does it VERY well, is Bill Buxton. :)
 
Sorry to confuse the issue, guys. I wasn't expecting a hamon line on my 1095 knives. I used the clay because I use a more or less vertical quench tank, so rocking the blade with controlled depth is not an option for me right now. So, I just used the clay to try to establish a differential heat treat, not get an actual temper line/hamon. That said, based on pics it's more than reasonable to expect a difference when you etch, etc. Like I said, the steel definitely hardened after the quench, and I can't get the edge to do squat (chip or bend) on brass rod, so that seems cool, but there is also no temper line when etched. I clay coated, heated a little past critical, and quenched the entire blade, which is what I do with 1095, but I am wondering if the part under the clay still may have hardened?
 
Then all the information you need to figure this out has been mentioned at least once in this thread. :)
 
Raker is correct.One of the easy things about O-1 is its ability to harden throughout.
Click to expand...

That must be it, then. It'd be nice to have a handy Rockwell tester on my bench right about now! :D I will clean it up to a nicer degree and see what I see. Maybe there will be a temper line up the handle somewhere! Guess I'll have to build a special quench tank for this O1. I will get the hang of it sooner or later! :D

On a side note, where would one look in the yellow pages to find big, beefy u-channel aluminum?
 
Fitzo, we are cool. No disagreement intended. I was seeking to learn and between you and Nick, I think you have clarified the issue. Intent/design of the pattern as well as the method of achievement (clay coating, heat treatment and polishing) are the real differences.

Here is an O1 blade I did several years ago using torch hardening. I was seeking the pattern you see in the blade. This is sanded only without any etch. While it takes some practice, O1 can create a very nice "transition zone". :D

BTW - My photography sucks. Great discussion, guys.
 
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