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Persians around 1000 AD purposefully added chromium to steel (not stainless)

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  • Persians around 1000 AD purposefully added chromium to steel (not stainless)

    From the article:

    Ancient Persians were forging alloys made from chromium steel as early as the 11th century CE, according to new research published today in the Journal of Archaeological Science. This steel was likely used to produce swords, daggers, armor, and other items, but these metals also contained phosphorus, which made them fragile.

    “This particular crucible steel made in Chahak contains around 1% to 2% chromium and 2% phosphorus,” Rahil Alipour, the lead author of the new study and an archaeologist at University College London, said in an email.
    https://gizmodo.com/1-000-year-old-p...-ir-1845145184
    Last edited by Dan_the_Chemist; 09-23-2020, 03:30 PM.

  • #2
    I wonder if the chromium was added deliberately, or accidently?

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    • #3
      There was also the Ulfberht sword, Nova & PBS has had some good documentaries on it where a modern blacksmith attempted a re-creation.
      Fashioned using a process unknown to the Vikings’ rivals, the Ulfberht sword was a revolutionary high-tech blade as well as a work of art. Considered by some to be one of the greatest swords ever made, it remains a fearsome weapon more than a millennium after it last saw battle.
      Max.

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      • #4
        Originally posted by old mart View Post
        I wonder if the chromium was added deliberately, or accidently?
        -Almost guaranteed to be accidentally. Extracting chemically useful chromium out of ores was well beyond what any Persian could have done, and it's basically not found as an even partially pure metal. It wasn't even officially "discovered" 'til the dawn of the nineteenth century. It'd be like the Persians intentionally adding aluminum or titanium to the iron.

        Basically it wound up in the iron through unrefined ores or even as trace minerals in the coal burned to do the forging.

        Doc.

        Doc's Machine. (Probably not what you expect.)

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        • #5
          They might not have had any idea what chromium was, but they might well have had the experience of knowing what percentage of what different ores or process materials to use to get a characteristic they wanted.
          .
          "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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          • #6
            They probably knew where it was mined and made a better product, once they realised it., other ore for other uses.
            The other element that was detrimental, they probably could not refine out..
            but the chromium may have lessened the strength loss of the other... result better stronger..

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            • #7
              Originally posted by old mart View Post
              I wonder if the chromium was added deliberately, or accidently?
              The title says purposefully, that means intentionally.

              They may have known from past experience that adding chromium adds strength.

              At at first it probably was added accidentally. then the sword maker realized the difference between swords made with chromium and without.

              Interesting article.

              JL.....
              Last edited by JoeLee; 09-23-2020, 05:56 PM.

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              • #8
                They probably never heard if chromium. They just knew that ore from +×÷=÷ Mine , made for better swords. ... I think. .

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                • #9
                  Ahhh come on its the Aliens.
                  Beaver County Alberta Canada

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                  • #10
                    Originally posted by old mart View Post
                    I wonder if the chromium was added deliberately, or accidently?

                    The process used was crucible reduction and smelting of ores... They would put iron oxides and other ores into a long narrow crucible, along with charcoal and other reducing agents, seal it all up, and heat it as hot as they could. Manuscripts from the time contain recipes for making crucible steel and they often contained a reference to "rusakhtaj", which they have identified as a chromium containing sand. They have found the remains of a lot of those crucibles and they have analyzed the residues inside of the crucibles. They found traces of the same chromite sand in the crucibles.

                    So, they didn't know it was "chromium", nor why it helped. But they found out that if you put a couple of percent of rusakhtaj in the crucible it made a far better product.

                    A quote from the article:
                    Excavations at Chahak resulted in the discovery of residual charcoal in old crucible slag (waste matter that’s left over after the metal has been separated). Radiocarbon dating of this charcoal yielded a date range between the 10th and 12th centuries CE. A scanning electron microscope was used to analyze the slag samples, revealing traces of ore mineral chromite. Finally, an analysis of steel particles found in the slag suggests the Chahak crucible steel contained between 1% to 2% chromium by weight.

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                    • #11
                      I LOVE threads like this..... did you know that something similar was used thousands of years ago in India, to produce what is now called "Wootz" ... it was prized for centuries, worth more than gold at one point... archaeologists have found that the Indian crucible steel had a couple percent of vanadium, gave similar results to the Chahak crucible steel. Back around 2,500 BC

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                      • #12
                        Are They sure it was not just the village miser using mystery metal He scrounged at the local dump.
                        mark costello-Low speed steel

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                        • #13
                          It's easy to assume our ancestors didn't know much about metallurgy. I'm thinking along the lines that they knew far more than we give them credit for.

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                          • #14
                            If you’re into this kind of stuff you can get lost in this site for weeks:

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                            • #15
                              Originally posted by RB211 View Post
                              It's easy to assume our ancestors didn't know much about metallurgy. I'm thinking along the lines that they knew far more than we give them credit for.
                              They may not have known it in the same way we know things now, but they definitely were pretty good at cause and effect..... use this and you get that.... eat this , you get sick, but not if you boil it several times and change the water each time, or make it into flour and boil, or ferment it... (cassava root).

                              So using a certain material to get improved iron properties is well within the realm of possibility.
                              1601

                              Keep eye on ball.
                              Hashim Khan

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