These events predate the Elg family by about 600 years, but since iron-making plays such a large role in our family history, I think this may be of interest:
From the early middle ages until the late 19th Century, the charcoal-fired blast furnace was the mainstay of the iron-making industry (see http://elgfamily.blogspot.se/2010/07/role-of-blacksmiths-in-ironmaking.html ). It has long been thought that this technology was imported to Sweden from Germany in the 14th Century.
However, a 10-year research project involving both historians, metallurgists and archaeologists has now overturned this view. The study has shown that blast furnaces were in use in Sweden as early as the 11th Century, and since these are the earliest findings of this kind, it is not unlikely that the technology was in fact developed here.
And the Swedish tradition of exporting high quality iron and steel started already with the vikings, as production capacity exceeded what the local market needed.
The study, Bengt Berglund et al "Järnet och Sveriges medeltida modernisering" (Iron and the medieval modernization of Sweden), is currently only available in Swedish, and has been published by Jernkontoret, the Swedish Steelmaking Industry Association, an institution which itself dates back to 1747.