Chromium steel, commonly known as stainless steel, is considered a recent product innovation, but new evidence suggests that the ancient Persians stumbled upon an early version of this alloy about 1,000 years ago, much to the astonishment of archaeologists.
Ancient Persians made alloys made of chromium steel in the early 11th century CE, according to the new Research Published today in the Journal of Archaeological Science. This was the prospect of steel Used to make swords, cutters, armor and other items, but these metals also contained phosphorus, which makes them fragile.
“This special crucible steel made in the fan contains about 1% to 2% chromium and 2% phosphorus.” Lead author of the new study and archaeologist at University College London, Raheel Alipore said In an email.
Archaeologists And historians, up to this point, were quite certain that chromium steel (not to be confused with chrome – the same Something else) Was the latest discovery. And indeed, stainless steel as we know it evolved in the 20th century today And Contains more chromium than steel produced by ancient Persians. Alipore said ancient Persian chromium steel “would not be stainless.”
The researchers wrote that the new paper “provides preliminary evidence for the continuous and intentional addition of chromium mineral, mostly chromite, to crucible steel charges, resulting in the purposeful production of low-chromium steel,” the study wrote.
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Due to the translation of medieval Persian manuscripts, the research team led fans to an archeological site in southern Iran. The fan was an important center for steel production, and is the only archaeological site in Iran to have evidence of crucible steel-making, in which iron is added to long-tubed crucibles, along with other minerals and organic matter, which are then heated in seals and fur.No.C.E. After cooling, the crucible is broken and an ingot is removed. This technology was alive and well in many cultures, including the Vikings.
“Crucible steel is usually very high.Quality steel, ”Alipore said. “It does not contain impurities and is very ideal for the manufacture of weapons and armor and other equipment.”
The key manuscript used in the study was written by the Persian polymath Abu-Rehan Biruni, dating to the 10th or 11th century. Entitled “Al-Jamahir fi Marifah al-Zawahir” (translated in “Gemstone Knowing Compendium”), the manuscript contains instructions for forging crucible steel, but says it is a mysterious compound. rusakhtaj (I.e. “burned”), which the researchers interpreted And then identified As being a chromite sand.
Excavation at the fan resulted in the discovery of the remaining coal In old crucible slag (waste matter left after metal separation). Radiocarbon dating of this coal gives a range of dates between the 10th and 12th centuries CE. The slag electron microscope was used to analyze slag samples, which showed traces of ore mineral chromite. Finally, the analysis of steel particles found in slag suggests that the fan crucible steel contained between 1% and 2% chromium by weight.
Alipore explained, “The chromium crucible steel made in the fan was known to contain only its type of chromium, which is known to us as important for the production of modern steels such as tool steel and stainless steel.” “Fan chromium crucible steel would be similar to modern tool steel in terms of its properties,” and “the strength and hardness of the chromium material, would increase the properties needed to make tools.”
“Persian crucible steel objects and objects can be found in museums around the world, and we already know that crucible steel was used to make sharp weapons, armor,” he said. Decent objects, And other equipment. The fan is also mentioned in historical manuscripts as the place where crucible blades and swords were made, but reports “the blades were also sold at a very high price, but they were brittle, so they lost their value.”
Phosphorus, which was also found during the analysis, was added to reduce the melting point of the metal But also to reduce the hardness a little, which later made the metal fragile.
Regardless, the discovery draws attention to the distinctive Persian tradition of steel making, which is very important. To the best of the author’s knowledge, the special chromium content found in fan steel can be used to distinguish it from other artifacts.
“Previous crucible steel evidence studied by scholars is from crucible steel production centers in India, Sri Lanka, Turkmenistan and Uzbekistan,” Alipore said. “None of this shows traces of chromium. Therefore, the identification of chromium as an essential component of fan crucible steel production has not yet been found in other well-known crucible steel industries. He added: “It’s very important, Because now we can find this element in crucible steel objects and back to their production center or method. “
To that end, researchers hope to work with museum experts to share their findings And to help with dating and identification These unique chromium steel signature objects.
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