Archaeometallurgy, experimental bloomery iron making in Tranemo

Here is part of the introduction:

Quote:

Lars-Erik Englund lars-erik.englund@swipnet.se Before the experimental furnaces were built in 1989 the project "Early Iron Making in Kind" had been ongoing for many years. It started in 1982 when the local History Association in the parish of Tranemo, in south-west Sweden, began mapping charcoal pits and slagheaps. This work was intensified during 1984 and 1985 when the state organised survey of ancient monuments came to this region. This survey, organized and carried out by The Central Board of National Antiquities, included all kinds of ancient monuments, but particular attention was given to the bloomery sites. In all we have documented 87 bloomeries in Tranemo and about 190 in all of the jurisdictional district of Kind. This figure can be compared with approximately 7000 bloomeries, and 850 blast furnaces, in the whole of Sweden. A new method of surveying charcoal pits and slag heaps was invented. Tools were developed to locate these very difficult, hardly visible structures in or on the ground. With a soil-probe, metal-needle, knife, gardening spade and a magnet it was possible to find many slagheaps and sometimes even roasting places, anvil stones, anvil slag and smithing pits in the woods. Questions about technic and site organisation was raised and in 1987 the first excavation started. Until autumn 1993 the local History Association in cooperation with Lars-Erik Englund carried out three excavations, two in the village of Arnås in Tranemo and one in the village of Örsås in Örsås parish, 30 kilometres west of Arnås. In all three cases we found a pair of furnaces, a technic and organisation which seems to dominate in the region. During the period AD 800-1350 there are, as far as we know, no other technique used. Before this period there are rare examples of a different kind of furnace, with diffrent slag, e.g. no tap slag, and no spatial connection with the charcoal pits. At about AD 1350 it seems that bloomery iron making disappeared but iron smithing did not. Scythe smithing is rather famous in this bloomery region up to the beginning of the 20th century. Twin furnaces are not spread all over Sweden. They are to be found only in the south-west parts, in the counties of Västergötland, Halland and Småland. Halland belonged to Denmark before the middle of the seventeenth century. Furnaces somewhat similar to the twin furnaces, dating back to Viking Age, have been reported from Norway but not from the Danish mainland. In parts of Europe twin furnaces have been reported from Bellaires and Boécourt in Switzerland and from the neighbourhood of Montpellier in southern France. These European twin furnaces are a few hundred years older than their Swedish counterparts. It is, however, interesting to note that the twin furnace technique was only used by the Vikings facing towards the western parts of Europe. This technique was not used by the Vikings in eastern Sweden. It seems that Viking Age iron making technology in eastern Sweden was, in many ways, traditional and had strong roots back into Roman times......

This is a site showing results from several years of "Hammarede" gatherings. However this is all in Swedish but it does have photos and diagrams.

Just found these sites interesting and thought some of you might find it also.

Thanks, Laurie. That was an interesting article - at least the English part that I could read. It is clear that they have learned many things through the mentioned 37 experiments. Since experiment 36 took place in 1995, it seems that there might be more recent information that has not been documented on the English page.

The Ekomuseum.com website has a series of links and short essays about ironworking/smelting in this region of Sweden. Their "Links" page takes you to various place under this topic (where I found the subject in the first place) and smithies using ancient techniques to smelt and forge iron. Most are in Swedish but a few do have English pages. Or Babelfish will help. Swedish Iron was considered the best during it's long history.

Dunshammar is reportably the oldest Iron Age furnace in the Bergslagan region. The iron was taken from lakes/bogs to smelt and the essay tells how this was done. Iron Age furnaces found date from 300AD.

What does have to do with myArmoury.com's subject? Iron is the base product for edged weapons and armour. Smithing techniques, tools and skills are still the backbone of a traditional bladesmith/armourer. We are just more specialized in how we use them. Also it is the question of just when steel made it's appearance and used for weapons. Patternwelding is all good and fine but steel was being made rather early. But when?

But also it is how far back ironworking and smelting was done in Europe. Just as Otzi's small axe pushed back how far the Copper Age for Europe to change dating. So, just how far back does the European Iron age go? It is spoken that there were mines with high grade iron ore in parts of Bulgaria, Germany and Spain where manganese and chrominum was in the mix.

Musings

Hello Laurie,

Good of you to put focus on some work being done in Sweden!

K G Lindblad was one of my first teachers in forging steel to tools. He does great work and dedicates himself to teaching his knowledge to new generations of smiths. A great guy.

The making of iron and steel is very early in scandinavia.
It seems there is a band of craft tradition and methods that spreads from the Ukraine via south-central Sweden up to the trondheim area of Norway. Same type of furnaces I´ve been told.

Already during the bronze age there was contact between south-west central Sweden over the baltic sea down the russian rivers. These traderoutes are what the vikings are famous using in their travels, but trade was established along these waterways at a very ealry date.

At irregular intervals a small group have a sort of informal seminar meeting here in Uppsala.
Eva Hjärthner-Holdar is an archaeolmetallurgist who has revealed many fascinating aspects of early metallrugy at these meetings. She makes analyses of slag at early iron making sites. In the area of lake Mälaren (South-central Sweden) she has found slag that resulted from the making of carbon steel of 0,6% carbon, dated to the 7th C BC.
This is late bronze age...

So at least some guys knew something crucial at a really early date. This does not tell us anything of how widespread this knowledge was or how controlled the processes were, but I think there is reason to have a humble attitude towards the skill levels of ancient craftsmen.
It is very obvious they could tell the difference between pure iron, phosforous iron and carbon steel and sought to use the different materials to best advantage, importing those qualities that were not made locally.
There is some reason to beleive that the different shapes of the raw trade/currency bars of iron/steel showed what type of material it was made of. Even if they had no idea of carbon or any other inclusions, they could control the methods in the making of specific types of iron.

It is great to see groups of enthusiasts striving to rediscover the ancient techinques of iron making. I would very much like to learn more about this, and if possible to take part in some experiments at some time.

You are welcome.

Then you would like to read this bit from the "Archaeology of Hand Tools" article from the Davistown Museum website: Clicking on the various topics takes you to the individual sub topics.

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Scandinavian (Swedish) iron, low in sulfur, was the key resource for Sheffield cutlers, beginning at least as early as the 15th century. With the development of the cementation furnace for steel production after 1550, Sweden remained the main source of iron for English toolmakers until the late-19th century despite the importation of significant quantities of colonial iron from Maryland, Virginia and Pennsylvania after 1740. But the most important developments in early modern European iron and steel production occurred to the south of Scandinavia and England in southern Germany.

Here is what they say about European Iron metallury being from the Caucasus region and spreading from there. Iron and small quanities of "natural" steel was made during the Bronze Age