2000 year old sword

[OceanoNox]

Picture 4 in page 3 of the Nojima report is of an iron axe found in Kanagawa (the piece held with his fingers). It is shown as evidence of it not being folded (due to lack of delamination), and thus possibly cast.

[vajo]

Stupid question a little scifi.

When you melt iron in a vacuum (with a laser or inside a fusion reactor) and cast it, is it also brittle?

[ROKUJURO]

Chris,

yes. The brittleness does not depend on the process but on the properties of cast iron.

[vajo]

So the iron atoms need the pressure of forging to find theire place. 

 

But what is with Temperguss (Tempercast)

GJMB-650 

 

Its near steel i think. 

 

I think forging is more easy than casting in the end. 

[ROKUJURO]

11 hours ago, Dan tsuba said:

.....The only thing that is “predictable” is your constant negativity.  If you know so much, why try “belittling” me and others and say that “no knowledge was gained”?  Did you have a bad day today?

 

Anyway, I await your “professional and superior” video showing the same scenario as the “amateurs” did in their video.  If you think you can do it better, have at it!....

Dan, 

I don't have a video of my activities (although a few photos exist, see in the attachment with me on the left. We made everything right, so we were successful). In general, well known facts don't need an explanation, and I won't give an excuse for my critical comments. 

Clumsy experiments like those in the video lead nowhere, and the lot of material and work that was invested by the guys would have been worth a good study of the processes beforehand. In the end, it was no serious attempt and they were just playing around with fire.

Most of the questions you arise could have been answered easily by studying the available litterature, so while I admire your tenacity, I often feel that it goes in the wrong direction.    

[Alex A]

I am a bit confused here, hoping for some clarity.

 

Briefly.

 

The small sword has been described as "CAST", by experts.

 

Just a straight bar, no cross guard to add any complexity to the cast

 

Seen Dans video where a few dudes "cast" a rough iron (whatever you want to call it)

 

Now, if they did that, why cant some iron "wizards lol" 2000 years ago do the same ?. Its not exactly the Angel of the North or anything.

 

Then file the "whatever you want to call it" into a neat sword, rather than hammer.

 

Perhaps they managed to get it neat first time, with a technique the guys here are not aware of  

 

That's if they had files

 

I say this because it is described as "CAST" by "EXPERTS"

 

Can this be answered without the use of a time machine, i would think someone will know, even if not here.

 

ps, just looking at the sword again, its not exactly neat, but maybe thats down to corrosion, dunno

 

Image from the “CAST” iron sword video that Dan presented.

 

Cheers

[ROKUJURO]

1 hour ago, vajo said:

So the iron atoms need the pressure of forging to find their place. 

 

But what is with Temperguss (Tempercast)

GJMB-650 

 

It's near steel i think. 

 

I think forging is easier than casting in the end. 

Chris,

it is more the fact that even tempered cast iron still contains too much carbon to be worked on in the forge. In theory, the carbon content limit of workable steel is about 2%. In practice, you will find that steel with 1.6% is already difficult as the workable temperature range becomes very small. The steel will fall apart at higher temperature and can get cracks if forged at low temperature.

The  high carbon content works like an inner splitting element in cast iron, driving the molecules apart under the hammer blows.

And only as much as 0.78% of carbon can be solved in an iron matrix, resulting in an eutectoid steel with wonderful properties!

Read this:  https://www.giesserei-praxis.de/giesserei-lexikon/glossar/temperguss

With todays technique, casting iron items has become easy, especially if made in high numbers. If we think of individual workpieces like a TSUBA blank, this is easy and fast work, done better in a forge. 

Considering the Japanese approach to arts in the SAMURAI age, the time it took to finish a nice TSUBA by a master was of no relevance.

I don't think Rembrandt van Rijn (or Picasso, for that matter) was ever asked how long he took for one of his paintings.....

[OceanoNox]

1 hour ago, vajo said:

When you melt iron in a vacuum (with a laser or inside a fusion reactor) and cast it, is it also brittle?

It depends on the carbon content (and other alloying elements). If you melt pure iron in a vacuum (or in an inert gas), you still get pure iron and it will be ductile. The brittleness of cast iron comes from the high carbon content.

 

By the way, there is also (but it is a relatively recent invention) ductile cast iron, which has graphite in the form of spheres that .

[OceanoNox]

6 minutes ago, ROKUJURO said:

And only as much as 0.78% of carbon can be solved in an iron matrix, resulting in an eutectic steel with wonderful properties!

The solubility limit of carbon in ferrite is about 0.02 mass%. The eutectoid steel is just fully pearlitic, that is lamellae of ferrite and cementite (eutectic is the point where the liquid solidifies into two solid phases at constant temperature, eutectoid is austenite transforming into both ferrite and cementite).

[ROKUJURO]

Arnaud,

today we even have cast (hardenable) steel, used for example in anvil production.

[Rivkin]

It appears to be the same old story. All pre-10th century iron swords found in Eurasia are basically random. Some show evidence of lamination, many don't, some were clearly hammered a lot, others don't, some are 0.4% carbon, others zero, the silica has any shape and size you can possibly imagine.

Its not mathematics so definitively proving something on the basis of such data is hard, but the scientific community is 100% tribal. So in Europe such distribution is attributed to someone digging out the material out of what looks more or less like tatara and thinking - this piece is good and I'll laminate it, and those we never had luck even heating well enough, so I'll just shape it somehow as a stick with a (sort of) edge, and that will still be useful and sellable. Though admittedly full of holes and slag inside.

 

If you want to publish an article in proceedings of Chinese Conference on Archeology, this will not do. The distribution observed is the result of intrinsically different methods used to produce the material itself - some is wrought iron, some is cast iron, some is pig iron which was decarburized etc. etc. etc.

You have to pick the side where you want your tenure.

 

For the dating, the most basic (and common) method for pre-mass literacy eras is establishing a set of "proved" sites where you have coins or writings and then you say - the site nearby has more stuff on top of it, so its older. Textbooks give you some idea how to convert centimeters into years. Precision is about 200-500 years, mostly depending on how close are the "reference" sites. In pre-Heian East Asia, where material culture can be rather conservative and writings are not often found (and often doubted), establishing such reference can be difficult, and dating can be quite a bit challenging... 

So maybe this particular case is more "datable", maybe its not, but in general every method is bound to give you a _range_ of dates. Replacing it with a single number is strange, but some people do it when it supposed to be "the oldest" of its kind. You see in publications bronze swords dating 2000-2500 BC, and then suddenly "sword, 3350 BC". Because the author promotes the find as the "oldest known".

 

I had numerous dealings with Japanese institutions which had rather run of the mill circa 1800 Indian or European blades or mounts (apparently the desire for new things was not just shinshinto), and they wanted a nod that yes, this is Japanese imitation of European or Indian work, produced for the Otomo Daimyo (Shimazu, Hizen etc.), because it is from Kyushu and we know that the find's date is definitvely 1560. They have zero interest in this not being the case. One told me Indians could not produce it because they don't use chopsticks so the finger motorics is lacking to make a fine inlay. After having a Japanese girlfriend who did not want to learn swimming because "Japanese have very heavy bones and always sink", I was not surprised. 

But its really not Japanese problem: Scientists in the Academia do generally dislike error bars or admitting the unknown. If it says you'll all perish in plague, you'll all perish in plague unless Professor gets the funds to save us.

All of these does not mean frankly that the statements made in the paper are "bad". Its just a complex question by nature.

[Dan tsuba]

Hello all!

 

And the research continues!

So, I found an article written in May of 2022 in the China Daily.  Most of the article is cited below-

 

“Ancient decarburization kiln discovered in Central China”-

 

“Archaeologists have discovered a decarburization kiln dating back to the Warring States Period (475 BC -221 BC) in the Houduanwan cast-iron relics site in Henan province.

 

The site, in the city of Xinzheng, was an official workshop for casting tools and weapons for the State of Han, which was active during that period.

 

Experts have also detected spherical graphite in the unearthed ironware, which was found to be processed by decarburization of cast iron and other procedures, according to the Henan Provincial Institute of Cultural Heritage and Archaeology.

 

More than 20 relics related to the cast-iron handicraft industry and a large number of pottery models, ironware were among the many other items discovered that relate to cast iron.

 

This discovery shows that China mastered ductile iron technology early in the Warring States Period, and pushes forward the history of ductile iron in China at least 200 years," said Fan Wenquan, a researcher with the institute.

 

According to Fan, it is generally believed that modern ductile iron technology was developed by British scientists in 1947. The discovery of the Houduanwan site proves that Chinese iron casting technology had entered a golden age during the Warring States Period as craftsmen had mastered the process.”

 

 

The article is from the below website (most of the article is stated above, but it does have an interesting picture of a cast iron relic that appears to be part of a sword and its hilt, and some pictures of the casting site)-

 

https://global.chinadaily.com.cn/a/202205/30/WS62941e04a310fd2b29e5fb39.html

 

So, the adventure continues!

With respect,

Dan

 

 

 

[Alex A]

Amazing what you can find out on the internet.

[Dave R]

An interesting article indeed, thanks for sharing. I do suspect though that they were casting "Knife Money" rather than swords... 

[Dan tsuba]

Hello David!

 

Chinese knife money?  Never heard of it!  So, I looked it up.  Thanks, I learned something new today!

 

I don’t know.  I compared the relic found at that Chinese archaeological site with some pictures of some ancient Chinese weapons (attached below).  It looks to me to be more like a piece of a sword and its hilt than Chinese knife money (website of sword pictures listed below)-

 

https://encyclopedia.pub/entry/28168

 

But who knows?  Unfortunately, the dimensions of the relic were not given in the article.  Although the article does state that the cast iron site was used for casting tools and weapons.

 

Anyway, we will see what other research I can come across!

 

Onward!

With respect,

Dan

[Dan tsuba]

Hello all!

 

So, here is the result of my latest research!  This article states how cast-iron swords and knives (along with other items) were being made in ancient China.  I mean I could have interpreted the article incorrectly, but that is what I derived from it! 

 

Now, on page 3 of the article I believe it states that cast iron was hammered into shape (malleable cast iron?).  Anyway, I would appreciate opinions from the metallurgists on the forum to help me correctly interpret the article.  Maybe I am completely wrong!

 

So, below is the title of the article and the “conclusion”-

 

“Archaeological and Anthropological Sciences- Original Paper Published: 07 September 2019-

 

“Iron decarburisation techniques in the eastern Guanzhong Plain, China, during Late Warring States period: an investigation based on slag inclusion analyses”

 

https://doi.org/10.1007/s12520-019-00921-5 Authors Yaxiong Liu1 , Marcos Martinón-Torres2 , Jianli Chen3 , Weigang Sun4 , Kunlong Chen1,5 1 UCL Institute of Archaeology, 31-34 Gordon Square, London WC1H 0PY, UK 2 Department of Archaeology, University of Cambridge, Cambridge CB2 3ER, UK 3 School of Archaeology and Museology, Peking University, Beijing 100080, China 4 Shaanxi Provincial Institute of Archaeology, Xi’an 710043, China 5 Institute of Historical Metallurgy and Materials, University of Science and Technology Beijing, Beijing 100083, China

 

“Conclusions-

 Building on the current development of analytical approaches to differentiate between direct and indirect iron products, in this paper, we analysed a series of early iron objects recovered from the eastern Guanzhong Plain, using a systematic analytical approach based on metallography and slag inclusion analysis. We obtained a relatively large dataset of slag inclusion compositions per sample and analysed the data with reference to previous research. This procedure, combined with a fundamental understanding of the underlying technological processes and the thermochemical behaviour of different elements, allowed us not only to identify samples as derived from indirect smelting processes, but also to further differentiate their decarburisation techniques. Based on the results, we can draw the conclusion that during the late Waring States period, various decarburisation techniques were applied for soft iron production based on cast iron smelting in the eastern Guanzhong Plain. In addition to providing the earliest evidence for the application of the Chaogang (fining) technique, this paper provides new pointers for research on the early development of iron production techniques in the Central Plains area. The new evidence suggests that, despite intrinsic differences in technical procedures and cost efficiency, solid-state annealing and liquid fining of cast iron co-existed for soft iron production in this region. Whilst iron metallurgy in the Guanzhong Plain has not attracted much research previously, our work suggests that during the late Warring States period, this area was actively engaged in developing and innovating iron production techniques based on cast iron smelting. Future research should further investigate the evolution of these two refining techniques and the circumstances under which each of them would have been employed, in addition to exploring the relationship between the direct and indirect smelting processes in Early Iron Age China.”

 

(Page 9 of the below article shows the ancient items that were tested.  Included in the analysis is a knife and a sword.)

 

https://www.repository.cam.ac.uk/bitstream/handle/1810/299143/Liu%20et%20al,%202019,%20Iron%20decarburisation%20techniques.pdf;sequence=1

 

This paper is 24 pages in length.  It is extremely scientific with samples of the metal found in the ancient relics and electron microscope images.

 

I could barely understand the whole paper!  But I am sure the metallurgists out there will find it very interesting!

 

Onward, and the adventure continues!

 

With respect,

Dan

 

[Jacques D.]

On 12/16/2022 at 11:41 AM, vajo said:

Stupid question a little scifi.

When you melt iron in a vacuum (with a laser or inside a fusion reactor) and cast it, is it also brittle?

No, because there is no carbon added. You can melt iron  with a laser but not in a fusion reactor.  

[Jacques D.]

On 12/16/2022 at 11:45 AM, ROKUJURO said:

Chris,

yes. The brittleness does not depend on the process but on the properties of cast iron.

The brittleness depend above all of the rate of carbon. If you melt iron with a laser there is no addition of carbon and therefore no hardness.

[Dan tsuba]

Hello all!

 

So, according to the last researched and referenced article I posted the Chinese developed “malleable cast iron” during the “Warring States” period in China (who knew!).

 

https://www.repository.cam.ac.uk/bitstream/handle/1810/299143/Liu%20et%20al,%202019,%20Iron%20decarburisation%20techniques.pdf;sequence=1

 

The Warring States period in China was from about 475 B.C. to about 221 B.C.  According to the article, they obviously learned how to cast iron (in a blast type furnace), decarburize it, hammer it and shape it into weapons (and other items).  I can only imagine that this method would be a lot quicker than “hand forging” weapons from bloomery furnace iron.

 

I believe (upon research) that the first tatara furnaces were developed in Japan in the 6^th century A.D. (the 6^th century would be in the 500 A.D. years).  We also know that Japan received a lot of technology from China.

 

I quote a part of page 3 from the article-

 

“As a result, this process allowed ancient metalsmiths to bring down the carbon content in cast iron to a desired level. With proper control of time, temperature and atmosphere, this technique provided the first technical solution to convert cast iron into low carbon soft iron, which could be further hammered or forged into final products (Li 1975; Yang 1980; Wagner 1989; Hua 1982).”

 

So, between 221 B.C. and 500 A.D. (about 700 years) was the Chinese malleable cast iron technique and formula “lost to history”?  Or was it just discarded to use the much slower method of hand forging weapons from bloomery iron from a tatara (which would result in a much better weapon?).

 

I can also guess that the 2000-year-old sword shown in the beginning of this thread perhaps was one of those “cast iron” swords from China that ended up in Japan.

 

With respect,

Dan

 

[Dan tsuba]

Hello all!

 

So, any thoughts and opinions on the “malleable cast iron” article mentioned in my previous post?  It is amazing what the “ancient masters” in China achieved with their technology!  I mean “malleable cast iron” appears to have been developed about 2400 years ago!  They made swords, knives, and other items.

 

And could that technology have been “borrowed” by Japan all those years ago?  And looking at the condition of those recovered artifacts in the article, it is amazing that those items just didn’t totally “rust to nothingness”!

 

The adventure continues!

 

With respect,

Dan

[Alex A]

Dan, admire your tenacity for getting stuck into this, 

 

Some good finds, 

 

 

[Dan tsuba]

Hello all!

 

So, kind of interesting.  I have read various threads on this forum where several individuals have stated that cast iron could not be hammered (it was not malleable).  Now, we have documented scientific research that states that it was done (malleable cast iron at least 2400 years ago, and it is unknown to what year it was continued).

 

All I hear is the “sound of crickets” in response to that fact.

 

What’s up with that?

 

With respect,

Dan

[ROKUJURO]

As the history of sword forging in Japan only started in about 500 CE, it is probably not interesting.

[Alex A]

Dan, you successfully proved that a ceremonial sword can in fact be cast/hammered.

 

99.9 % here are clueless on such matters, i guess that's why there is not much response. Old skills get lost through history.

 

 

[Jacques D.]

20 hours ago, Dan tsuba said:

Hello all!

 

So, kind of interesting.  I have read various threads on this forum where several individuals have stated that cast iron could not be hammered (it was not malleable).  Now, we have documented scientific research that states that it was done (malleable cast iron at least 2400 years ago, and it is unknown to what year it was continued).

 

All I hear is the “sound of crickets” in response to that fact.

 

What’s up with that?

 

With respect,

Dan

 

You don't understand the subject. Cast iron is an alloy containing more than 2% carbon. Below 2% it is no longer cast iron but steel. To be able to forge, we decarburize the cast iron to make steel, it's as simple as that. It is so trivial that the authors of the study did not feel the need to specify it.  

[Dan tsuba]

Hello all (and Happy New Year!),

 

So Jacques (referring to his last post)  you are correct, I do not understand the subject as much as you do.  But I am trying to learn!  So, I reviewed the article, and it lists a percent of carbon content chart (I have only included the one “sword” and three “knives” carbon content). 

 

So, the carbon content is above the 2% (0.02) percent that you stated (although could it be that the authors made a mistake on their percentages?  As an example, on the F29 sword it states 0.5% percent carbon – that is 50% carbon!  Did they mean to say 0.05% carbon?).  So, it would appear (if you are correct about the below 2% carbon content being steel) that these artifacts are above the 2% carbon content and are indeed cast iron.

 

Although the article is very complicated and scientific (and I probably misinterpreted the article or made an error somewhere!), and I am trying to understand it without returning to University and getting my master’s degree in metallurgy!!

 

Table 3 Brief description of the

metallography of samples and

approximate carbon content

Lab no. Typology Description of matrix C wt.%    SI analysed

 

F29 Sword Widmannstätten structure 0.5%             49

 

Kn10 Knife Layered microstructure of ferrite and pearlite 0.6%          24

 

Kn11 Knife Homogenous distribution of fine ferrite and pearlite 0.4%

 

2432 Knife Layered microstructure of ferrite and pearlite 0.6%          42

 

Above from the below website-(another website that lists the same article – couldn’t access it from the other website previously listed in my posts!).

 

https://www.researchgate.net/publication/335683873_Iron_decarburisation_techniques_in_the_eastern_Guanzhong_Plain_China_during_Late_Warring_States_period_an_investigation_based_on_slag_inclusion_analyses

 

Onward!

With respect,

Dan

 

[ROKUJURO]

Dan,

The F 29 sword with WIDMANNSTÄTTEN structure (https://en.wikipedia.org/wiki/Widmanstätten_pattern) 

was obviously ground from meteorite material. If it were cast or forged, the structure would be lost.

The other knives are forged.

0,5% carbon content means 0,5% C - from 100 parts, one half part is carbon. School basics!

The whole subject has nothing to do with Japanese blades which the NMB is devoted to and which we are interested in.

 

[Dan tsuba]

Jean, my friend-

 

Your “belittling” attitude towards me continues!

 

So, (from your last post) in your "all knowing" capacity you stated that the F 29 sword “was obviously ground from meteorite material.”  Right!  So, how many swords have you made from meteorite material?  Although throughout history there have been a few swords and knives made from meteorite material, they are extremely rare.

 

Also, some quotes from your previous posts on this thread-

“As the history of sword forging in Japan only started in about 500 CE, it is probably not interesting”.

 

And - “School basics!

The whole subject has nothing to do with Japanese blades which the NMB is devoted to and which we are interested in.”

 

So, now you speak for everyone on the forum!  Who are you to say that this is not an interesting subject or has nothing to do with the evolution of Japanese swords! 

 

Your constant “put downs” and "negativity" and “Mr. know it all attitude” is indicative of an individual with a massive “ego” that refuses to learn anything new.  Psychology basics!

 

Just letting you know that your attitude is not apprecieated by me (and who knows, maybe others feel the same way?).  You will not keep me from researching what I find interesting.

 

Dan

[Brian]

Half a percent Carbon. Just to re-iterate. 0.5% is 1/2
So well below the 2% and therefore steel

[Dan tsuba]

Hello Brian,

 

Thanks for your post and your patience. 

 

Now (since math is not my strong point!) I am confused (again!).

 

The article states 0.5%.  And we are trying to compare that to 2%.  Now, 0.5% is 50%.  I believe it would be correct to compare 50% and 2% (or to compare 1/2% to 2%).  But 0.5% is not less than 2% if both are written in decimal form.

 

I say that because if 2% is written as a decimal (as the 0.5% is written) it would be 0.02%.

 

So, 0.5 would be more than 0.02.

 

I don’t know, I am probably overthinking this!  Just want to make sure I am interpreting everything correctly, so I can learn.  Where are the mathematicians!

 

With respect,

Dan