Stone unknown?

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Hi everyone, I had a little old lady come and pick up a Yosimitu Kajiya 180mm Shirogami 2 Gyuto she order a month ago and she brought in her sharpening stones. One was a double sided Norton India in a box, nice condition. The other one was this
IMG20221003132506.jpg

I gave it a quick lap and gave a knife a quick polish on it. I didn't bring up much slurry but it brought out the Damascus cladding on this usuba. The knife had been on a 600 diamond before so no Damascus was showing.
IMG20221003134216.jpg

Just wondering if anyone (@cotedupy ) would have an idea about the stone?
IMG20221003132509.jpg
 

HumbleHomeCook

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Thanks for the heads-up on the Arkansas soft @stringer & @HumbleHomeCook .

I've just recently got my second Washita but I had never played with an Arkansas before.

Washitas are actually Arkansas stones. I've long believed that true Washitas were mined out quite some time ago but there are far more knowledgeable folks on that than me.

That said, a soft Ark was for many, many, many years my stone of choice. I still regard them as among the best stones I've ever tried. They're almost a do-all stone, just based on pressure and technique.

After many decades of using them with oil, I just can't get beyond not doing so although many folks do. With my foray into Japanese knives, my sharpening style has evolved and I now employ the common "scrub" type style and that isn't real friendly to an oily stone.

At any rate, I've sharpened a hoop of knives off soft Arks and think they provide great versatile edges.
 

cotedupy

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Yep, what the other guys said - soft ark.

One of the most underrated stones out there. May not have the finishing range of a Washita, but that means that they're a little bit better for bevel stuff. I too have found them very good for picking up layers in steel. :)
 
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That aint no damascus my friend! It looks more like 'dirty' jigane - a bit like wrought iron... or possibly some sort of banding.
Nah it's Damascus, I had been playing with the knife on a 600 diamond. I then went straight onto the soft Arkansas and the Damascus came out in no time.

I brought the blade as a Damascus usuba. Just a "practice" knife, it works well as a test knife on stones too, I can see how good stones polish with this blade.
 
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Nah it's Damascus, I had been playing with the knife on a 600 diamond. I then went straight onto the soft Arkansas and the Damascus came out in no time.

I brought the blade as a Damascus usuba. Just a "practice" knife, it works well as a test knife on stones too, I can see how good stones polish with this blade.

😯

Do you have a wider shot of the knife? I don't want to be 'that guy'... but it really does not look like a typical pattern welded steel. The pattern is more characteristic of 'clouds' seen in some J-tool jigane... those are often closer to wrought iron or some form of banding.

But I'll take your word for it! :)👍
 
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Nah it's Damascus, I had been playing with the knife on a 600 diamond. I then went straight onto the soft Arkansas and the Damascus came out in no time.

I brought the blade as a Damascus usuba. Just a "practice" knife, it works well as a test knife on stones too, I can see how good stones polish with this blade.
I always thought it was damascus but it could be another type of cladding. I gave it a little polish but I didn't get a picture of the whole blade sorry.
IMG20221005103856.jpg
IMG20221005103924.jpg
 

cotedupy

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😯

Do you have a wider shot of the knife? I don't want to be 'that guy'... but it really does not look like a typical pattern welded steel. The pattern is more characteristic of 'clouds' seen in some J-tool jigane... those are often closer to wrought iron or some form of banding.

But I'll take your word for it! :)👍


🙋‍♂️

I vote this might be a good time (if you don’t mind, and have a moment) to explain the exact differences in the forging and folding process of ‘damascus’ vs pattern welded steels that show this kind of ‘banding’, and why they do.

I’m sure everyone else knows, but it’s something I’ve never quite got my head around 100% tbh. And when you try to look it up there’s often a lot of confusion, and different definitions thrown about...
 

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🙋‍♂️

I vote this might be a good time (if you don’t mind, and have a moment) to explain the exact differences in the forging and folding process of ‘damascus’ vs pattern welded steels that show this kind of ‘banding’, and why they do.

I’m sure everyone else knows, but it’s something I’ve never quite got my head around 100% tbh. And when you try to look it up there’s often a lot of confusion, and different definitions thrown about...
My understanding is pattern welded steel is two different types of steel.


"So the name "damascus" is a misnomer and when we say "damascus barrels", we really mean "pattern welded barrels". In pattern welding, two or more metals are used to make the barrel (usually iron and steel bars, or steel bars of varying carbon content)."

 
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🙋‍♂️

I vote this might be a good time (if you don’t mind, and have a moment) to explain the exact differences in the forging and folding process of ‘damascus’ vs pattern welded steels that show this kind of ‘banding’, and why they do.

I’m sure everyone else knows, but it’s something I’ve never quite got my head around 100% tbh. And when you try to look it up there’s often a lot of confusion, and different definitions thrown about...

@Desert Rat has it right.

There are some points to add. Hehe... I dont know whether to do the long version or the short version? 🤪 Let's see where we go.... Read it with a little caution. I think I have the high-level points about right... but I am not an expert. So there may be some errors!


I think the most flexible approach to working with the English language is to recognise that it is constantly evolving. After enough time and 'abuse' words can shift their definition to a colloquial meaning even if that usage is not textbook correct. So.... is it wrong to call pattern welded steel damascus?? Not really! It depends who you ask. While this loose usage might disappoint metallurgists and historians, for the remaining majority it successfully communicates: "steel with a pattern in it".

What if anything do we lose by being lax with terminology? We lose history and we lose a bit of metallurgy.


As I understand it, Damascus 'steel' predominantly refers to Iron and Middle age weapons that were made in the Eastern Mediterranean. During this period of history, the Syrian city of Damascus had a thriving weapons industry. This is why patterned steel is called 'Damascus steel'. This in itself is a quirk. The actual steel, was likely imported from India, Sri Lanka or Persia. And like the spralling spice and silk routes, a number of countries spanning Europe, Asia and the Eastern Mediterranean manufactured weapons using this patterned South Asian steel! So why was patterned steel named after Damascus? I dont know the answer to this... *I* suspect it is probably due to cultural and academic bias? Perhaps evidence of it in the Levant region was documented in the (Christian) Western world before Asia's fundamental role was properly recognised.

The important South Asian steel we are talking about is called 'Wootz' steel. Wootz is a crucible steel - it was made by sealing a carbon rich source and iron inside a clay crucible. The crucible was then placed in a coal furnace and left to soak in the heat. During the soak, carbon migrates out of the carbon rich source and into the iron, making a steel. As the steel forms, a network of carbides grows within the material producing the characteristic pattern. While I believe a blacksmith can enhance and manipulate the pattern through thermal cycling and forging, the sheets of carbide originally formed organically when the steel was made.

Whether or not you can make modern Wootz is a philosophical one. Are you replicating an exact traditional process? From which specific country? From which specific time period? A specific alloy? Are you only replicating the pattern? Does it have to be a combination of all things considered? Given these questions, I am not so sure anyone can really claim to have an authentic Wootz recipe. The important thing to recognise is that Wootz is a historical South Asian crucible steel - a single alloy of steel with an internal network of patterned carbide sheets.

To some degree, pattern welding can replicate the appearance of Wootz/Damascus steel. This is why it is commonly called 'Damascus steel'. In pattern welding, two or more steel alloys (different steels) are forge welded together. The number of layers can be increased by folding the steel billet over on itself. Patterns can be introduced by the way the billet is manipulated. The important thing to note here is that multiple steel alloys are being welded together and manipulated to create a pattern. Patterned carbide bands are not required.

In summary... as I understand it:
  • Damascus steel: Eastern Mediterranean weapons made using wootz during the iron and middle ages
  • Wootz steel: a South Asian crucible steel with an internal network of patterned carbide sheets - also referring to historic steels spanning the iron and middle ages
  • Pattern welding: forge welding multiple steels together. This can create an aesthetic that is similar to Wootz but is done using a different process (multiple steel alloys welded together) and results in different metallurgical properties (carbide network/sheets are not present)
 

psfred

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Traditional Damascus steel has patterns in it from differential precipitation of carbides in what was probably Indian crucible steel. The composition of the steel and the forging techniques resulted in variable carbide precipitiation as the steel was worked, and a talented forger could make some fancy patterns that show up as the steel is polished.

It also was much more flexible and held an edge far better than the coarse low carbon steel made in wood fires in the rest of Europe at the time.

Partially art and partially accident, as not all Indian crucible steels produced good patterns, and as steel making became more scientific and less secret Guild information, the uneven distribution of carbides disappeared in tool steels. Which is not a bad thing, actually.

Modern "damascus" steel is just steel of various different combinations stacked and forge welded to mimic the appearance of the old Damascus steel, and usually doesn't have any of the great properties Damascus steel had -- mainly because ANY knife steel in use to day is vastly better than Damascus was when new. Modern stuff is purely decorative, not functional.

The pattern in the knife is quiestion looks more to me like wrought iron, which incidentally is a great cladding. Farily low carbon, so it isn't brittle for support, and is softer than hardened steel so it's not a huge chore to grind it off when thinning. For things other than knives, it's also great since it is "dead" in comparison to hardened steels, so works great to dampen vibration in plane blades and other woodworking tools. Old ship anchor chains were in great demand in Japan for many years as a result since they are cheap and wrought iron. Modern ones are rolled steel, and not at all the same.
 

DanielC

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There's already a lot of good information that's been said. I've been out of touch all weekend so I am late to the party.

I will inject however, that there are some somewhat misunderstandings.

Crucible steels in history and even Wootz have varying chemistries, however, the concentration of these elements are very low, usually. We are talking in the trace ranges and some cases just a bit higher. So ~.005%-.1% by weight concentrations of carbide forming elements, such as Vanadium, Chromium, Niobium, Phosphorous, Tungsten, etc...

The funny thing about ore deposits, is that you can crush and send an ore sample from under your feet and take 5 paces in any direction in that ore deposit and take a sample and have pretty distinctly different concentrations of elements from ore sample to ore sample. I have done this in practice. My smelting partner and I have sent off dozens and dozens of samples of ore to be tested from various ore deposits in my country. We do this for our traditional smelting.

I've also never encountered an ore or even a piece of scrap metal that didn't have the minimum required concentration of elements to create carbide formers capable of being nodes to eventually create a watering pattern.

The carbide formers play an important role, but they do not really make up the pattern you see. They tell the cementite (iron carbide) where to go every time the steel is heated back up, but unlike "alloy banded" monosteels in modern steels, crucible steel's pattern is made up of extremely tiny spheroidized blobs of iron carbide with the foreign elements more or less are somewhat evenly scattered amongst the steel, and these exist amongst a sea of pearlite. They are where they are from the time of solidification, and my melting procedure ensures these to be as evenly dispersed as possible. The lamellar sheets of cementite in low alloy crucible steel can be seen below. Keep in mind this is a cross sectional view (like from the spine).

wootz_cementite_arrangement (1).jpg

In alloy banded steels, the less pronounced swirly patterns are made up of large, irregular non-ferrous carbide with high concentrations of cementite gathered (cementite is attracted to non-ferrous carbide more, the larger the carbide is), while leaving zones of carbon depletion, forming ferrite. Below is an image I found of an alloy banded steels. I am not sure of the alloy, but alloy banding looks pretty similar amongst many samples I found. Layers of highly concentrated carbide, and ferrite.

post-1266-1110908566_thumb.jpg

Both form patterns, but both are created differently.

But to my main point, Wootz is just a moniker for crucible steel made from certain ores, but it is very easy to just use similar chemistries (which we do) to make the steel. Smith's have been doing that for years. What smith's haven't been doing for years, except for a very small few, until recently, was forging it correctly. That was the real mystery all of this time. That is part of what Verhoeven and Pendray figured out. However, despite the years of research and their papers, some specifics on how to do this were intentionally left out of any video, book or paper published.

It's taken a handful of us years to finally pull proper patterns through correct forging. It took a long time sort out the methods to doing so, which is where the actual magic occurs (ingot chemistry is a purposeful distraction).

The blade in question looks like alloy banding in mild steel that has high Manganese maybe. Manganese is notorious for this. I've had it happen myself, on accident. Or it's wrought.

Edit: I should say this is my interpretation. I'm not a metallurgist.
 
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This is absolutely fantastic reading material.

Crucible steel is phenomenal when done correctly, it is not a simple task, is a precise mix of elemental ingredients to be consistent.

The chemical analysis we have access to in modern day allows for incredible steel instruments, our current steels are mind blowing, to say the least.
An example is CPM M4 although not very beautiful visually it’s a juggernaut of chemistry and metallurgy. Wootz on the other hand can be superb in performance, it shines in visual appeal with micro grain structure and can be very different from one ingot to the next.

I think an M4 core with wootz cladding would be stellar, anyone know a maker foolish enough to try??
 
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