Here's a question for you that are more of a metalurgist than I. I know that most (if not all) who use clay when heat treating use carbon steels. How much of an alloy can be used and still get a distinct hamon? Thanks in advance.

Gary

Not much....the slight bit of chromium in 5160, for example, makes it near impossible to get a hamon on it. Any alloy that increases hardenability will make the hamon less distinct.

However, 01 tool steel shows a nice hamon (when edge quenched, I've never tried the clay on it), just not as nice as 10 series steels. Same goes for 52100 and L6.

Understand there is a differnce between a hamon and a quenchline. A hamon is created by claycoating a simple steel i.e 10xx steel to get a crips transformation line when polished properly. 5160 WILL get a nice quenchline if HTed properly as with other steels,0-1,52100 ect but these are not a hamon.

If a quench line is different then please explain what you're seeing in a quench line.

Thanks,
Gary

Hamon and quench line are two different words for the same thing and acheived two different ways. Another term is temper line which is incorrect because it has nothing to do with tempering. If you have a structure of martensite on the edge and pearlite on the spine [however you get it] the two structures will polish and etch differently and give you hamon/quench line.

Man, great thread! Cleared up a misconception I had, thanks guys.

I know that many use Satanite for their clay but have often wondered if simple potter's clay would also work. Has anyone tried this and what kind of results can you expect?

Gary

I've never tried potter's clay but I have tried fireplace cement, which seems to work just fine. Unfortunately, it's sticky, annoying to work with, and must be allowed to dry thoroughly before bringing up to temp lest ye want gooey black bubbles bubbling up on your blade...

From a metallurgical standpoint yes they are the same but from a polishing and finish stand point they are vastly different. and thinking on it im not convinced a water quenched hamon is exactly the same properties as oil quenched quench line, but thats another topic.

Hamon vs. quench line,

I was at a knife show admiring the hamon on a little hunter. The guy next to me said it was all wavy and I should look at this other guys work "...'cause his is straight. The guy that made the knife you're looking at just doesn't know how to do it."

I tried to explain they're two different beasts. He just stared at me for awhile, then explained what straight means.

Steve

The discussion of the inaccuracy of the term temper line comes up all the time. Have you ever wondered why so many people use it? Don't automatically assume that the person hasn't done his homework, or that he is ignorant or being deceitful.

Metallurgists and some makers who lean absolutely to the purist side tend to get very fidgety over the term temper line. Personally, I don't have a problem with it, and do upon occasion employee the term myself.

First let me say that temper line is in fact technically incorrect based on modern metallurgical terminology. The hardening line, quench line, transition line, or whatever you choose to call it, has nothing to do with the tempering phase of heat treating. We all agree on that. That being the case one would wonder why in the world I don't have a problem with the term.

Simple. It is a hold over from history, long before we knew what we know now. It is from a time when it was quite common to refer to the entire process of heat treating as tempering the steel.

To help illuminate this, below are some excerpts from a manuscript by Daniel Webster Jones, who served as the Governor of the State of Arkansas from 1897-1901. I've chosen this example because it involves James Black, a smith accredited with the creation of the famous Bowie knife.

With failed eyesight, James Black was taken in by Dr. Issac N. Jones and family, which included the infant Daniel Webster Jones. Dr. Jones had hoped to be able to restore at least some of James Black's sight. It was not to be the case. James Black lived with Webster family some thirty years.

###

Time and time again, when I was a young boy, he would say to me that not withstanding his great misfortune, God had blessed him by giving him a good home among friends, and that one day, when I had reached maturity, he would disclose to me his secret of tempering steel.

...

On May 1, 1870, which was his seventieth birthday Mr. Black told me that, since in the ordinary course of nature he could not expect to live much longer, he had decided that the time had arrived. He stated that I was old enough and sufficiently well acquainted with the affairs of the world to properly utilize the secret, and that if I would procure pen, ink and paper, he would communicate his knowledge to me.

...

When I came to him at the end of the third hour Mr. Black burst into tears saying: "My God! It is all gone from me! All these years I have accepted the kindness of these good people in the belief that I could partly repay it with this, my only legacy. Daniel, there are ten or twelve processes through which I put my knives -- but I cannot now remember even one of them. A few hours ago, when I told you to get the writing materials, everything was fresh on my mind. Now it has flown. I have put it off too long!"

...

His sightless eyes were filled with tears, and his face expressed utter grief and despair. I could only say: "Never mind, Mr. Black. It is all in the wisdom of God. He knows best; and undoubtedly He had His reasons for allowing the secret of the Bowie-Knife to remain with you."

...

God gave him the secret for His own purposes, but was unwilling for him to impart it to others.

###

James Black was no dummy. He was known for his quality knives. His secret ten to twelve step heat treating process was done behind a leather curtain. Nobody will ever know precisely what those steps were. He referred to the entire process as tempering the steel. Now you know the story.

Neat little story - thanks for posting that excerpt, Terry.

Terry, been thinking, yes I know that is dangerous. But do you suppose that the 10 steps of James Black were something like this, normalize 3 times, anneal 1 time, quench 3 times. temper 3 times? These are the steps some of us follow at least in part. Like I said just wondering. Gib

For what it's worth, I did an analysis on one of Don Fogg's sword blades when we were trying to figure out why water made the blade bend up and oil made it bend down. He used a 1095 steel but the chemical analysis suggested it was actually 1084. One piece of steel, forged to a blade on both ends, clayed the same, one end quenched in water, one in oil, tempered the same. Almost the exact same hardnesses and very similar microstructure in the hamon line. I think the report is still posted on his site under the Metallurgy section. Go back to last year to find it.

Now, I know why I don't post to often.
Raymond Johnson

Why's that Raymond?

Quenchcrack,
I've got ot go check that thread out. This one's been a mystery for many of us for a long time.

Gib,
Beats me. I'll admit that's at least crossed my mind as a possibility. I guess I'm getting farther off topic, but there's a good deal of info on James Black. It's just that nobody knows what his procedure was.

I did read what one of his standard tests was though (he was one of us who believes in testing every knife). He would sharpen the blade then whittle on some hard hickory for one hour. After that one hour the knife had to still shave hair. If it didn't then the knife was considered junk. I can't remember where I read that.

Interestingly, a friend and fellow forumite just sent me a beautiful photo of a knife he recently completed. It had a very nice hamon. I asked him about it, and he said it was 5160 steel, and the HT was done with a torch, heating the blade edge part (not the spine) to non-mag, then quenching the entire blade. After tempering, he did some sanding, etching, and buffing, the the hamon was there. I had always thought that either clay, or a partial quench must be used for a hamon, but I was wrong. Maybe he'll chime in and post his photo.

Robert,

The most interesting thing that I have seen was while doing an interupted quench in water on a piece of 1095. I immerced the blade three times edge first and got three different hamons. This was quite by accident and I'm not sure that I could ever duplicate it. BTW, the owner didn't like it and buffed them out.

Gary

Gary,
I believe that's how Anders Hogstrom gets his very active hamons, although, if I remember the conversation I had with him coreectly, he uses primarily 1060 for his plain carbon blades

Gary, did you use plain tap water? Did you completely submerge the blade, or just partially?

Robert I've seen a blade like that done slightly different:

First some facts

*The Hamon is the transition from martensite to pearlite (or whatever).
*You make martensite by quenching from austenite
*If it's not hot enough you get pearlite (or whatever).
*If it doesn't quench fast enough you get pearlite
*Thin parts heat faster than thick parts

Hamon method 1: Get the entire blade to austenite and quench part of it (clay or edge only).

Hamon method 2: Get only part of the blade to austenite and quench all of it (like your friend did)

OK Ready for this? If you heat the blade in a salt bath, the temp is very even. However, the edge gets to temp before the rest. If you pull it out at just the right instant and quench, you'll get a hamon.

The most incredible, flaming hamon I've ever seen was done this way. I really didn't believe it when he told me the process. However, I realized it wasn't an edge quench with a straight hamon and it didn't follow any line you could make with clay. It was wild!

I'm not going to mention the maker, he might want to keep the details to himself. So, I can see that happening in your example, Robert.

Steve

Very interesting guys! Up until the last few days I had understood that the hamon was caused by partial quenching, or clay coating the spine area. This calls for a lot of thought, and a few experiments. Fascinating!

I went over to Don's website and found he has recently converted to another software package for his forum. Many of the old photos did not make the conversion. Evidently, the report, which was in pdf format did not convert either. If anyone wants a copy, I would guess Don would repost it on his site and you can down load it. I have the original but since I gave it to Don, it is technically his so I am hesitant to give it out without permission. As was mentioned previously, the hamon is a transition from the martensite of the edge to the pearlite of the spine. As you go up the blade, you see a greater percentage of pearlite. I got some nice photomicrographs of this from the blades Don provided. :D

Robert,

Sorry that I am so slow in responding but have been at a show and am just getting back to normal schedule. On the blade that I mentioned previously I quenched in pre-heated well water, edge first. The entire blade had been heated to critical and the first two quenches were completely immersed but removed as quickly as possible. The third quench was held under until cool. My original thought was to prevent that dreaded "tink" not to achieve any type of hamon.

Gary

Ok, thanks Gary, I got it now. I've yet to try this in water, and I'm sure I'll hear (and probably feel??) the dreaded "clink" or "tink" when I try it.

Gary,
To answer your original question, The metallurgy is critical. The best hamons are produced with the simplest steel possible. Iron and carbon ONLY. One of the reasons modern blades have hamons that are not up to the standards of the old blades is that our modern steels have to many additives. Even the small amount of manganese used in all modern steels to help wth pouring the molten metal makes a difference. I have had several requsts by sword makers doing blades with hamons for steel with no manganese or any other additives for this reason. I have yet to make any. perhaps someday
Delbert
www.ealyknives.com

Thanks Delbert. That's what I had thought but in reading about ancient wootz it got me wondering if traces of things like vanadium & moly might not enhance the pearlite formation. Guess I need to remember the KISS rule.

Gary