MOSCOW, Feb. 25, 2022 /PRNewswire/ -- NUST MISIS scientists together with their colleagues from the Lomonosov Moscow State University and the State Historical Museum have investigated the famous Vikings' swords from the burial mounds near Smolensk. As a result of the metallographic examination, scientists have obtained data that explain the excellent properties of the legendary blades of the 10th century with the medieval workshop Ulfberht hallmarks.
NUST MISIS metallurgists examined several swords of the 10th century from the archaeological complex of Gnezdovo near Smolensk and the burial mounds of the South-Eastern Ladoga region. The blades found during the excavations were marked with the hallmarks of the famous weapons workshop Ulfberht.
Ulfberht is a modern transcription of the +VLFBERHT+ inscription commonly found on Frankish swords from the early Middle Ages, 8th-11th century. To date, about 170 Ulfberht swords, which have survived to this day, have been found. It is assumed that the famous workshop was located on the territory of the Rhineland.
The high-quality products of this medieval "brand", along with warriors and merchants, has dispersed throughout Europe, has been sold well and, as studies show, has often been faked. The combination of hardness and flexibility was a serious advantage of Ulfbert's swords.
Previously, scientists had only noted the very presence of hallmarks and the correctness of their spelling. However, it is only possible to obtain complete information about the quality of blades and the technology of their manufacture with the help of special structural studies, primarily metallographic studies.
"Vikings' swords could be made from steel of various qualities. Some of them would not have been able to withstand any normal blow: their blades were made of iron with minimal carbon content. But quality blades contain high carbon steel. There is a widespread legend that Ulfbert's swords are made of cast crucible steel, comparable in quality to modern metal. Our research refutes this myth: welds, structural heterogeneities and slag inclusions were found in all swords," says the head of the laboratory for Hybrid Nanostructured Materials of NUST MISIS, Ph.D. Alexander Komissarov.
According to the scientist, medieval blacksmiths in Europe did not make steel without slag because their furnaces were not powerful enough to remove them. Nowadays, metals are melted at temperatures above 1650 degrees Celsius. This temperature helps separate the slag and allows more carbon to be mixed evenly. But in the Viking Age, carbon could only get into steel when the processed metal was carburized in a fire, and the only way to remove slag was to try to knock out impurities with a hammer during repeated forgings.
"The studied swords turned out to be made according to classical schemes, but the quality of the materials used and the execution of the welds are different. The hallmarks on them are also different: the inscription "+VLFBERH+T" on the blade from the Ladoga region burial mounds contains an error - the last letter "T" is turned upside down. Researchers explain such cases by the fact that some of the blacksmiths involved in forging brands were illiterate. On one of the swords, traces of repair were found - the broken blade was shortened and reforged, and an additional piece of iron was welded onto its handle," says Alexandra Shchedrina, a master student at the Department of Archeology of Lomonosov Moscow State University, a graduate of the NUST MISIS Department of Metal Science and Strength Physics.
According to her, in medieval Europe, a loose lump of softened sponge iron was obtained in a mixture with slag and particles of unburned coal, which is formed during the smelting of iron ore under conditions of low temperatures relative to blast-furnace smelting.
"The materials available for the manufacture of weapons were heterogeneous and far from ideal in quality, and metallurgists learned to alloy steel much later. In order to obtain high-quality, solid and reliable blades, like Ulfberht swords, blacksmiths tried to combine different materials in one product: hardened steel was used on the edges, and the blade core was made of iron, which has the highest impact strength," concludes Alexandra Shchedrina.
Such studies using modern equipment help archaeologists not only understand how each particular specimen was made, but also advance in understanding the functioning of one of the most important international industries of the early Middle Ages.
SOURCE The National University of Science and Technology MISiS