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Scott Roush
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PostPosted: Thu 24 Mar, 2011 6:47 am    Post subject: Noric Steel - evidence for how it was made?         Reply with quote

I've been trying to dig up references for how steel was made in Noricum. All I can find are references to bloomery furnaces.. but was the steel made directly in the stack or did they have a refinement/carburizing feature following the iron bloom production? I would like to follow a historical process as closely as I can in my steel making endeavors, and this seems like a good model due to the (supposed) high quality nature of the steel.
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Henrik Zoltan Toth




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PostPosted: Thu 24 Mar, 2011 11:00 am    Post subject:         Reply with quote

Good evening!

There was a very fine documentary about this in a german chanel. The territory was hidden by a meteorite in the 5-6th Cent. BC, like the one of Tunguzka. It explodednear to the earth surface, (these territory is called Chiemgau) and it's remains are little metallpellets everywhere in the ground there (and even in honey, etc) or something like that. The celts there made double piramid ironblogs and these special blades from this material. The reenactment blacksmith in the film did paternwelding with his ironblooms.

Oh, and, according to the film, the celts begun after the meteorite came down, to use the burning whire as simbol and to fear the sky could fall down again Eek!

You should probably search in the german net.

Zoltán
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Mark Shier
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PostPosted: Thu 24 Mar, 2011 12:51 pm    Post subject: Chiemgau         Reply with quote

The Chiemgau impact theory seems to be more than a bit dubious. See http://scienceblogs.com/aardvarchaeology/2011...p.php#more and http://scienceblogs.com/aardvarchaeology/2010...sis_is.php
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Mark Shier
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PostPosted: Thu 24 Mar, 2011 1:06 pm    Post subject: noric steel         Reply with quote

For another theory, see http://www.3rd1000.com/chem201/chem204j.htm
From the article:

At Noricum, smelting yielded steel directly because iron carbonate ore such as that found there can produce it; the ore naturally contained some manganese so an alloy steel, and a good one, was obtained. A modern alloy steel, stainless steel, contains 0.4% carbon, 18% chromium, and 1% nickel. Noricum had 3 to 6-foot shaft furnaces with forced draft and some control of the degree of carbonization.

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Kurt Scholz





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PostPosted: Thu 24 Mar, 2011 1:15 pm    Post subject:         Reply with quote

Just scrap that Chiemgau theory, it's a bunch of funny pseudoscientists getting time and again their 15 minutes of fame. Their arguments so far are far from convincing.
There have been trials to reconstruct the production of Noric steel. If I remember correctly the trick was stopping the process before the smelted iron is too much decarburized by the heated airflow. In my opinion it has some resemblance to Sub-Saharan steel production.
The other method of production of that age were the Chinese and the Parthian method that mixed iron with higher and lower carbon content.
These might interest you:
Die Produktion von Ferrum Noricum am Hüttenberger Erzberg, die Ergebnisse der interdisziplinären Forschungen auf der Fundstelle Semlach/Eisner in den Jahren 2003 - 2005 (German)
Ferrum Noricum und die Stadt auf dem Magdalensberg (German)
Ferrum Noricum (German)
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Arne Focke
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PostPosted: Fri 25 Mar, 2011 12:16 am    Post subject:         Reply with quote

To put this theory into perspective.
Just try and imagine how much iron/steel was produced in that period.
After that try to imagine how big the meteor must've been to contain that much material.

Who would be left to mine the ore after such an impact. Wink

So schön und inhaltsreich der Beruf eines Archäologen ist, so hart ist auch seine Arbeit, die keinen Achtstundentag kennt! (Wolfgang Kimmig in: Die Heuneburg an der oberen Donau, Stuttgart 1983)
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Henrik Zoltan Toth




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PostPosted: Fri 25 Mar, 2011 1:22 am    Post subject:         Reply with quote

Yes, this makes sense.

Black celts Big Grin :

http://www.youtube.com/watch?v=bA9KwGcOxCk&feature=related

The wole process is on other video-parts. It may help to imagine how a whole village may had made iron products by the celts.

Zoltán
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Kurt Scholz





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PostPosted: Fri 25 Mar, 2011 4:06 am    Post subject:         Reply with quote

In the reconstruction of the Magdalensberg steel production they used a smaller bloomery (Rennofen) and weren't able to pull out the iron without first shutting down the whole process (but they discovered lots of problems during the trial, so this shouldn't be taken as a final verdict). If this archaeological reconstruction is right the depicted Africans run a more efficient system.
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Dan Howard




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PostPosted: Fri 25 Mar, 2011 4:57 am    Post subject: Re: noric steel         Reply with quote

Mark Shier wrote:
For another theory, see http://www.3rd1000.com/chem201/chem204j.htm
From the article:

At Noricum, smelting yielded steel directly because iron carbonate ore such as that found there can produce it; the ore naturally contained some manganese so an alloy steel, and a good one, was obtained. A modern alloy steel, stainless steel, contains 0.4% carbon, 18% chromium, and 1% nickel. Noricum had 3 to 6-foot shaft furnaces with forced draft and some control of the degree of carbonization.

Exactly. It is the same reason why ore from the mines in southern India was used to produce wootz. The ore natually contained just the right amount of impurities.
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Dan Howard




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PostPosted: Fri 25 Mar, 2011 5:13 am    Post subject:         Reply with quote

Arne Focke wrote:
To put this theory into perspective.
Just try and imagine how much iron/steel was produced in that period.
After that try to imagine how big the meteor must've been to contain that much material.

Who would be left to mine the ore after such an impact. Wink


Healy reckons that the total iron consumption in the Roman Empire was around 82,500 tons per year. If Sim's figures about smelter efficiencies are accurate and the ore contains about 50% iron then over 1.43 million tons of iron ore would need to be processed each year.


Last edited by Dan Howard on Fri 25 Mar, 2011 5:15 am; edited 1 time in total
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Scott Roush
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PostPosted: Fri 25 Mar, 2011 5:14 am    Post subject:         Reply with quote

Very interesting folks.... Thank you. I suspected that they were making steel directly in the stack. And interesting about interrupting the process....

Wootz was made from small pieces of iron in a crucible.... Not directly from ore. So are you saying that the iron that was used had an alloying element that made it's use in wootz more beneficial?

On another related topic... What do folks here know about European (pre blast furnace) methods for carburizing bloomery sourced iron into steel? My understanding is that most bloomeries throughout Europe were short stack, iron making furnaces. So I'm trying to gain an understanding as to how steel was made. I'm starting to now see that many folk had to import their higher quality steel... Either from places such as Noricum or regions making wootz.

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Dan Howard




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PostPosted: Fri 25 Mar, 2011 5:17 am    Post subject:         Reply with quote

Scott Roush wrote:
Wootz was made from small pieces of iron in a crucible.... Not directly from ore. So are you saying that the iron that was used had an alloying element that made it's use in wootz more beneficial?.

Apparently. If Mr Furrer is about, he could answer this better than most people.
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Kurt Scholz





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PostPosted: Fri 25 Mar, 2011 7:47 am    Post subject: Re: noric steel         Reply with quote

Dan Howard wrote:
Mark Shier wrote:
For another theory, see http://www.3rd1000.com/chem201/chem204j.htm
From the article:

At Noricum, smelting yielded steel directly because iron carbonate ore such as that found there can produce it; the ore naturally contained some manganese so an alloy steel, and a good one, was obtained. A modern alloy steel, stainless steel, contains 0.4% carbon, 18% chromium, and 1% nickel. Noricum had 3 to 6-foot shaft furnaces with forced draft and some control of the degree of carbonization.

Exactly. It is the same reason why ore from the mines in southern India was used to produce wootz. The ore naturally contained just the right amount of impurities.


Sorry but that sounds like comparing apples and oranges. There's some discussion about a stainless steel possibly being produced in the North Pontic region, but that's based only on interpretations of literature.
The Magdalensberg ore has a very high iron content in useable compounds. That makes smelting it into metal a more efficient process. I hope Arne says more about that because, as far as I know, they tried this ore at the Bajuwarenhof.
50% efficiency for the Roman bloomeries sounds like a gross exaggeration to me. They surely had more or less efficient bloomeries and, as long as their trade worked, operated on the higher levels of efficiency. For La-Tène bloomeries the estimate is about 20-25% normally and 50% would be extremely good conditions.
You are possibly overstating the importance of wootz, cast iron was more common to obtain and widely used for high carbon content, naturally mixed with other iron.
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Arne Focke
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PostPosted: Fri 25 Mar, 2011 8:43 am    Post subject:         Reply with quote

Kurt Scholz wrote:
In the reconstruction of the Magdalensberg steel production they used a smaller bloomery (Rennofen) and weren't able to pull out the iron without first shutting down the whole process (but they discovered lots of problems during the trial, so this shouldn't be taken as a final verdict). If this archaeological reconstruction is right the depicted Africans run a more efficient system.


We had a Rennofen like that in our Museum last year and it produced 10kg of raw iron. Can't wait to get it under my hammer, but it is still in the lab.

So schön und inhaltsreich der Beruf eines Archäologen ist, so hart ist auch seine Arbeit, die keinen Achtstundentag kennt! (Wolfgang Kimmig in: Die Heuneburg an der oberen Donau, Stuttgart 1983)
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Dan Howard




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PostPosted: Fri 25 Mar, 2011 2:13 pm    Post subject: Re: noric steel         Reply with quote

Kurt Scholz wrote:
Sorry but that sounds like comparing apples and oranges..

My point was that Noricum ore was desired because it had just the right level of impurities to make quality steel. The mines in southern India were used for the same reason.
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Kurt Scholz





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PostPosted: Fri 25 Mar, 2011 5:08 pm    Post subject: Re: noric steel         Reply with quote

Dan Howard wrote:
Kurt Scholz wrote:
Sorry but that sounds like comparing apples and oranges..

My point was that Noricum ore was desired because it had just the right level of impurities to make quality steel. The mines in southern India were used for the same reason.


I'm not so sure about that. I saw a map of Roman mining operations and their ore seems to have been from Aquitane and the western side of the Limousin mainly and to a much lesser degree from Noricum. While Noric steel had a reputation other mines seem to have had an edge in quantity. One part may have been the difficulty in mining, but also a less economic process to achieve the desired Noricum quality. So I'm still rather sceptic that the ore in Noricum was perceived as a kind of super-ore. If we look at Pliny there're many stories about good steel and Noricum and it's ore were just one source, not even the best, and other processes did yield superior results and were much more economic. I think we shouldn't limit the discussion just on the properties of the ore.
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Scott Roush
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PostPosted: Sat 26 Mar, 2011 5:35 am    Post subject:         Reply with quote

Kurt... Do you have a reference for using cast iron to carburize iron? Or time periods? I was under the impression that cast iron was rare in pre-medieval iron making or that it was considered useless. My understanding is that the furnace geometries were simply incapable of making cast.... But I'm still wet behind the ears in this pursuit...
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Arne Focke
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PostPosted: Sat 26 Mar, 2011 6:10 am    Post subject: Re: noric steel         Reply with quote

Kurt Scholz wrote:

The Magdalensberg ore has a very high iron content in useable compounds. That makes smelting it into metal a more efficient process. I hope Arne says more about that because, as far as I know, they tried this ore at the Bajuwarenhof.


I checked and yes that was the ore we used was from that source with an iron content around 90%.
My forge wasn't ready at that point, but my guess was, just from handling it, that I might have been able to forge it into a usable bar without it being sent through a "Rennofen" first.

So schön und inhaltsreich der Beruf eines Archäologen ist, so hart ist auch seine Arbeit, die keinen Achtstundentag kennt! (Wolfgang Kimmig in: Die Heuneburg an der oberen Donau, Stuttgart 1983)
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Kurt Scholz





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PostPosted: Sat 26 Mar, 2011 8:15 am    Post subject:         Reply with quote

Scott Roush wrote:
Kurt... Do you have a reference for using cast iron to carburize iron? Or time periods? I was under the impression that cast iron was rare in pre-medieval iron making or that it was considered useless. My understanding is that the furnace geometries were simply incapable of making cast.... But I'm still wet behind the ears in this pursuit...


China had cast iron since early times during the Spring and Autumn period or what we call the Warring States. I knew it as part of a the script of a lecture on technology, but there's also a source mentioned on this in wikipedia, another place to look it up would be Needham. More to come.
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Timo Nieminen




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PostPosted: Sat 26 Mar, 2011 3:06 pm    Post subject:         Reply with quote

Scott Roush wrote:
Kurt... Do you have a reference for using cast iron to carburize iron? Or time periods? I was under the impression that cast iron was rare in pre-medieval iron making or that it was considered useless. My understanding is that the furnace geometries were simply incapable of making cast.... But I'm still wet behind the ears in this pursuit...


Cast iron + low-carbon iron in a closed crucible, heat it, and you get crucible steel. Wootz is a variety of crucible steel from south India, but "wootz" is also used as a synonym for Indian/Central Asian crucible steel. There was a very large crucible steel industry in Central Asia for a few centuries on either side of AD1000. The process is older, perhaps a few centuries BC.

The Chinese used this process very early, but mostly abandoned it during the Han, in favour of direct de-carburisation of cast iron (they called this product "fried iron").

Not a European technology; seems to have been restricted to India, Central Asia, China, and Korea. Arab writers new of the process, but I don't know of any Middle Eastern manufacture.

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