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I'm trying to devise a plot point where a great sorcerer (who's also a bit of a renaissance man, alchemist, inventor, politician, etc.) who slays a dragon and use its corpse to carburize iron ore inside a volcanic mountain into steel (or tungsten into tungsten carbide) that locals might call it "dragon steel". Does this make sense? If not, what needs to be changed to make sense, or is there a way to create a similar effect?

Fantasy Science
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  • What is the phrase "carburize iron ore" supposed to mean? Iron can be carburized, iron ore cannot; it must first be smelted. (And then you need the slag removed; carburizing iron begins with almost pure iron.) Anyway, the source of carbon is mostly irrelevant; You can always convert the dragon into charcoal first, and use the carcoal. See for example how the Indians made Wotz steel (of which the famous Damascus blades were made). – AlexP Jan 03 '22 at 09:47
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    Could having a burned out dragon carcass mixed with iron ore, when smelted, provide enough carbon content to make steel in normal ironworking in a dark age setting before people fully understood the process? – Fantasy Science Jan 03 '22 at 09:51
  • What are dragons made of? How big are they (is it)? – Escaped dental patient. Jan 03 '22 at 09:55
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    That is not how steel is made or how it was ever made. There are two main ways to make steel. You can start with almost pure iron and add a tiny little bit or carbon; this is how Wootz steel and then medieval crucible steel was made. Or you can start with cast iron and remove most of the carbon; this is how post-medieval crucible steel and modern plain ordinary converter steel is made. To get almost pure iron, you smelt the ore in a bloomery; this gives you iron mixed with slag. You then remove the slag, for example by beating it out of the hot iron. – AlexP Jan 03 '22 at 09:56
  • @AlexP I'm not very knowledgeable about metalworking so I'm trying to figure out how to ask the question in the right way. So if my ultimate objective is to have 1) A super inventor-sorcerer 2) ??? 3) "Dragon Steel" exists, which is as good or better than common iron/steel available to dark-age Europe (doesn't have to beat wootz steel since that wont be commonly accessible) I'm okay if it needs to be further processed.

    Can the dragon be turned to charcoal by a massive fireball and directed to crash over iron/tungsten and future smiths remove the slag to create steel/tungsten carbide?

     – Fantasy Science Jan 03 '22 at 16:45
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    @AlexP Tamahagane the Japanese "jewel steel" is produced in a one step process from ore to steel without cast or bloom iron as an intermediary step, it is an exception in ancient metallurgy but it proves the process is possible. – Ash Jan 04 '22 at 02:33
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    @Ash: Isn't tamahagane just plain ordinary bloomery iron to which some carbon is added during the forging process? That is, first they make bad iron in a primitive bloomery furnace like they used in the antiquity and early middle ages in Europe, and then heat it red and hammer it and hammer it and hammer it endlessly on a bed of charcoal to remove the slag and hopefully add an uncontrolled amount of carbon? (The point being that it's a two step process. What they get directly from the smelting furnace is just iron mixed with slag, yes with some small amount of carbon.) – AlexP Jan 04 '22 at 02:43
  • @AlexP No, there is a process for carburising the low carbon material from the core of the tatara (sorry I can't remember the name off hand), but the tamahagane on the outer edges goes straight from the furnace into finished products at 0.5-1.5% carbon. – Ash Jan 04 '22 at 02:49
  • @Ash: Thank you for the explanation. I still don't see how the bad iron coming out of a bloomery furnace can be used directly without first beating it for a long time to remove the slag... – AlexP Jan 04 '22 at 02:50
  • this question may be very helpful for you. It is about what use a dragon could actually have in sword making. https://worldbuilding.stackexchange.com/questions/140413/quenching-swords-in-dragon-blood-why – John Jan 04 '22 at 03:15
  • Tamahagane does have to first be beaten for a long time to remove the slag. It is beaten, folded, beaten some more, folded some more... It has a higher carbon content than a homogenized bloom, but a lower carbon content than pig iron. – Nosajimiki Jan 04 '22 at 03:16
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    @AlexP Tataras aren't like western bloomeries, they're big, 4 cubic metre, rectangular tubs, instead of a 0.50 cubic metre cylinder, that process tonnes of material. The larger size and shape mean that the perfect conditions for forming steel exist in a large enough volume, and in a predictable area, that it can be separated from the lower quality metal, rather than being in small random pockets, out of a 2.5 metric ton bloom the high quality, immediately usable, tamahagane is only in the tens to low hundreds of kg range. – Ash Jan 04 '22 at 03:22
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    @Nosajimiki Really no, good tamahagane is, by definition, free of slag, it is flattened into slabs which are broken to assess their quality then stacked to the needs of the project, and forge welded into a billet, you fold it once, maybe twice, to consolidate the lateral welds between slabs but not to remove slag. – Ash Jan 04 '22 at 03:31
  • @ash You are mistaken, tamahagane comes from the outer boundary of the bloom where it has the most contact with the edge of the tatara. Being in the outer boundary, it gets the hottest; so, it absorbs the most carbon, but this also means that is absorbs the most slag from its contact with the side of the tatara. On average, it takes 5-10kg of tamahagane to make a 1kg blade. Those 4-9kg of lost weight are slag that needs to be hammered out. https://www.mext.go.jp/en/movie/sdetail01/1322073.htm – Nosajimiki Jan 04 '22 at 04:59
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    @Nosajimiki That in no way resembles the material or working process and information seen in either documentaries on traditional katana making nor what came out of modern tataras built and fired experimentally by a few people I know of. – Ash Jan 04 '22 at 05:07
  • @Nosajimiki As a note the mass lose to scale when making a pattern welded billet from modern steel can actually be far worse than that just from folding and forge welding clean modern steel. – Ash Jan 04 '22 at 05:11
  • @ash A couple more sources mentioning slag: https://ravencresttactical.com/all-about-samurai-steel/, http://www.ksky.ne.jp/~sumie99/forging.html. Keep in mind that traditional Tamahagane is made from iron sand which is only 2-5% iron. If you use other ores like goethite (~60% iron) in a tatara you can get a much more pure bloom. Also, modern tataras are often made with modern clays which will not melt and mix into the Tamahagane. Traditional tatara were made from whatever local clay was available. – Nosajimiki Jan 04 '22 at 15:27
  • @Nosajimiki I can find that 2-5% figure but I can also see quotes for iron sands with up to 58% iron by weight in Japan and flotation concentrated samples north of 60%. Like I said the material in the article/videos you linked didn't resemble the tamahagane used in either the documentaries I've seen on traditional katana making or what came out of the modern tatara firings I've been privy to. – Ash Jan 05 '22 at 03:02
  • @ash even a tamahagane made with 60% iron sand will have some slag. Certainly a lot less, but it will not be pure. Such a bloom can be handled in the same way as a traditional European bloom where you can make a passable blade without folding it, but it will still contain small impurities that will weaken it. The true value of tamahagane is not its purity compared to other blooms but its carbon content. It is really hard to get a medium carbon steel out of a homogenized bloom. – Nosajimiki Jan 05 '22 at 15:00
  • @Nosajimiki The tatara produces prodigious volumes of slag, my understanding is that the relatively high working temperature and the exceptionally long period (up to 72 hours) that the furnace is kept at working temperature allowed the iron in ideal areas of the bloom, anything from none of it to around a third, to separate fully from it's associated slag. – Ash Jan 06 '22 at 06:07

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You need to pyrolyse your dragon to remove impurities, particularly the phosphorus and sulfur as they have the most detrimental effects, that would damage the quality of the result. You could conceivably then use it as fuel in a Tatara style furnace to produce Tamahagane the high quality "jewel steel" of ancient, and modern, Japan. Tamahagane is an outlier in the world of ancient metallurgy in that it is produced in a one step process that goes from pure, high quality, ore and fuel directly to steel without carburising bloomery or decarburising cast iron.

If you want to use a volcano though I would suggest that blister and shear is the process for you. Low carbon reasonably pure bloomery iron is beaten into fairly thin bars that are packed in a carbon donor, usually charcoal or coke but in this case cooked dragon, in a stone box. The box is then brought to high temperatures, usually 600-800°C, and held there for days, or even weeks, on end while the metal absorbs carbon. This process used to be ruinously expensive because of the fuel consumption required to maintain the oven at working heat for such long periods, the volcano will be much cheaper. The name blister steel comes from the blistered appearance the bars take on where the absorbed carbon distorts their structure. Shear steel is the result of forge welding the bars together to more evenly distribute the carbon they had absorbed.

Ash
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  • Tamahagane is far from a 1 step process, and it does include carburizing in the refinement process (normally done using pyrolyzed rice grass). http://www.ksky.ne.jp/~sumie99/forging.html – Nosajimiki Jan 04 '22 at 15:52
  • @Nosajimiki Only for the parts of the bloom, sometimes all of it, that are lower quality. – Ash Jan 05 '22 at 02:45
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It's Magic

Assuming your "great sorcerer" is in fact a sorcerer and your "dragon" is in fact a dragon, then it makes perfect since. Dragons are considered in many mythoses to be the most magical of all creatures or even demigods. And a sorcerer is of course a person who specializes in the manipulation of magic, not science.

There is not a scientific reason to do this, but there is precedent

In many magic systems there is the concept of the reagent: an ingredient used in casting spells for the magical properties that it contributes, and in these systems reagents that are derived from dragons are often considered among the most potent.

In fact, some cultures historically did add un-pyrolyzed biological components to their steel specifically because they believed it imparted some mystical properties into their blades. Some Viking cultures for example would add a raven feather to their steel to impart the favor of Oden on it.

So sure, it could be argued that mixing dragon parts into your steel would weaken it because of the sulfur impurities... but so what? A sword made from sub-standard steel, but is also held together by primordial magic powers beyond our human comprehension is still going to be a large step above any steel made by non-magical means.

But maybe it's not real magic...

What if your great sorcerer is NOT in fact a great sorcerer, and your slain dragon is just some dinosaur fossil he found? Maybe your sorcerer is just an exceptional blacksmith with a flare for the dramatic.

Before modern science no body really understood WHY one steel was better than another, they only understood if you do the right steps you get a better result which sometimes creates superstitious extra steps. Going back to the Vikings, the metallurgy techniques invented in Northern Europe during the early medieval period were so much better than other European techniques at the time that Viking swords were often considered magical. So while that raven feather may have been an unnecessary step, the care they took in preparing their ores and the multi-alloyed pattern welding techniques they used did make their swords much better than those made by other smiths... so as far as anyone at the time was concerned, the raven feather worked.

Likewise, if your smith throws a little bit of fossilized dinosaur into his furnace, it will just melt out with all the other silicates, no harm, no foul. But as long as he does enough other things right with the carbon levels and the purification, and the tempering, etc. then his Dragon Steel blades could still be the best blades in the region.

Nosajimiki
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  • This is the "it's magic don't worry about the science" answer, I like and loath this answer but it's always an important point to make +1. – Ash Jan 04 '22 at 05:14
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Biomass is not made of carbon only: it contains also, among others, nitrogen, hydrogen, sulfur, phosphorus.

Most of them are normally undesired elements into steel (one of the theories on the sinking of the Titanic claims its steel was very brittle due to the sulfur content), therefore using biomass to dope steel will work, but not in a way that makes the steel particularly attractive property-wise.

L.Dutch
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    Most usually you first convert the biomass into charcoal... After all, charcoal made from biomass actually was the source of carbon used in steelmaking for about 2,000 years. – AlexP Jan 03 '22 at 10:14
  • @AlexP and when that carbon happens to be rich in sulfur one gets poor steel, until controlling the process is learned – L.Dutch Jan 03 '22 at 10:26
  • Doesn't the charcoalification process get rid of most of the sulfur automatically? – AlexP Jan 03 '22 at 10:48
  • @AlexP, no. Coal from Sulcis mines, in Sardinia, is an example of high sulfur carbon. – L.Dutch Jan 03 '22 at 10:57
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    Charcoal is not mined coal. Making charcoal involves partial combustion of biomass; I would think that any sulfur will be lost as sulfur dioxide gas. – AlexP Jan 03 '22 at 14:03
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    @AlexP The technical name for the "charcoalification process" is "pyrolytic carburisation" by the way, usually it's just "charcoal making", and yes the sulfur does burn off as a gas, (due to the low oxygen conditions more often disulfur monoxide than the dioxide though), along with the nitrogen, hydrogen, oxygen, and phosphorus. – Ash Jan 04 '22 at 02:24
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    @Ash: Charcoalification was intended to be humorous. I can see it failed. – AlexP Jan 04 '22 at 02:25
  • @AlexP Sorry usually does with me, I'm that guy who takes things literally regardless, especially in written media. – Ash Jan 04 '22 at 02:27
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    Nor is there any reason to prefer dragon charcoal over far easier to acquire tree charcoal. – John Jan 04 '22 at 03:19
  • @John Except for the Sorcerer angle that is. – Ash Jan 04 '22 at 03:32
  • @John That part is easy: Why hire entire villages to carry a forest into the volcano when you can just piss off one dragon and have the charcoal move itself? – Fantasy Science Jan 04 '22 at 04:48