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Metallurgy of Original 1800’s Bowie Knife Made by James Black

Discussion in 'Knife Reviews & Testing' started by Juha Perttula, Dec 2, 2017.

  1. Juha Perttula

    Juha Perttula Basic Member Basic Member

    79
    Mar 27, 2013
    A story tells that when James Black made the legendary knife for Jim Bowie he added a piece of meteorite in a crucible charge. Perhaps in that way he got exceptional Ni steel which was harder and tougher than other steels in his times. Among other things I have touched on this idea in my scientific article “Effect of Ni, Mn, V, and Al on Toughness of Blade Steels” https://www.jstage.jst.go.jp/article/isijinternational/55/10/55_ISIJINT-2014-606/_html
    In this current writing I solely focus on the idea of meteorite and Bowie knife.


    Bowie knife and meteorite

    There are many stories about the metallurgy of the original Bowie knife which was forged by James Black in the beginning of 1800’s. I like most the Paul Welman’s novel “Iron Mistress”. According to the novel James Black melted together steel and meteoric iron in crucible. The story is also dramatized and the meteorite melting scheme is in YouTube


    But can a piece of meteorite improve the properties of steel ?


    Meteoric iron–nickel

    Since prehistoric times man has forged blades from meteorites. Iron meteorites contain Fe, Ni, Co, S, P and C. The amounts of other elements are negligible. The percentage of these elements ranges quite a lot, but the average chemical composition is 0.04C–8Ni–0.5Co–0.2P–0.7P. Most of S is in large visible FeS inclusions, which can be removed, and the inseparable S content of iron is only 0.01–0.001%. I have forged some blades from a fragment of Gibeon meteorite. It was difficult to forge because it tend to fracture during hammering (hot brittleness). Non-hardened specimens were tough, but after carburizing and hardening the specimens were somewhat brittle. It should be note that ancient blades were generally non-hardened and thus meteorites were suitable blade material.


    Meteoric crucible steel

    According to the story James Black added a piece of meteorite in crucible melt. In other words he made crucible nickel steel. Ni steel has a reputation of good toughness, but in the times of James Black they did not add Mn or Al into steel, which are typical for modern steels.

    Without Mn addition S can weaken grain boundaries and result in brittleness, fracture may also occur during forging (hot brittleness). Mn binds detrimental S in harmless MnS inclusions. Old carbon steels, made from pure iron ore and charcoal, had a low S content, and for that reason, the S was not a problem despite the absence of Mn. However, Ni alloying makes steel more susceptible towards harmful effects of S. So, it is a good question, can also Ni steel be tough without Mn addition?

    Al alloying prevents grain growth, which makes heat treatment easier, and good toughness can easier be achieved. But can a skilled bladesmith attain a good toughness without Al alloying?


    My experiments

    Test materials

    I made two steels in crucible: totally unalloyed primitive carbon steel and hypothetical Black’s meteoric nickel Bowie steel. And took one factory made AISI 1080 steel which had Al alloying. The chemical compositions of tested steels were as follows:

    analyysi.png

    Test methods

    I heat treated the specimens to various hardness levels. I used double hardening because it gives finer grain size, and consequently better toughness. After heat treatment I ground the specimens into the size of 3.8x6x30 mm. Then I fractured them and measured the angle of plastic bending of broken specimens (Fig 1.)

    Fig 1.jpg
    Fig. 1 Example of plastic bending angle measurement. Specimen is bent until fracture, two pieces are refitted together, and the amount of plastic deflection indicates toughness.


    Results

    My test results are shown in Fig 2. When tempered to 57 HRC or softer, all steels were practically equal.

    At high hardness levels (64 HRC), AISI 1080 was best, due to Al alloying which resulted in superfine grain size. It had 5 degree of plastic deflection at 64 HRC, which is sufficient for woodcarving, but chopping may need more toughness.

    The maximum hardness of un-tempered Ni steel was 63 HRC. In that condition it was brittle, but when tempered to 62 HRC it was tough. An interesting finding was that at hardness level 58-62 HRC the “original” Bowie Ni steel was clearly tougher than the primitive totally unalloyed carbon steel and equal to modern Al-alloyed AISI 1080 carbon steel.

    plastic bending.png
    Fig 2. Plastic bending vs. hardness for fracture bent specimens of primitive carbon steel, Ni alloyed “original” Bowie knife steels, and AISI 1080 steel with Al-alloying. Large amount of plastic bending indicates good toughness.


    Explanation of the results

    The main reason for poor toughness of blade steel is brittle fracture along former austenite grains. During hardening impurities and thin carbide film forms on austenite grains; therefore, martensite tends to fracture along the former austenite grain boundaries.

    Al-alloyed AISI 1080 was tough because its fine grain size prevented the brittle grain boundary fracture mode. Primitive carbon steel had larger grain size, and for that reason, when tempered at low temperatures, it suffered grain boundary fracture. But high temperature tempering destroyed the carbide film on austenite grains, and brittle fracture mode vanished. Thus, at 57 HRC primitive carbon steel was as good as modern AISI 1080 despite its slightly coarser grain size.

    Obviously Ni alloying also prevented the brittle grain boundary fracture, and for that reason, Ni steel attained the good toughness.

    However, we must remember that the effect of Ni depends on the impurities, particularly S. A Mn containing steel with 8% Ni is very tough (I have tested it), because S is binded with Mn. Gibeon meteorite have also 8% Ni, but I did not get good result after carburizing and hardening. Obviously high Ni combined with impurities, particularly S, resulted the brittleness. I found with an electron microscope that the fracture mode was a brittle grain boundary fracture.

    If James Black added in crucible such kind of meteoritic iron–nickel which contained only a low amount of P and S impurities, he perhaps got similar material to my “original” Bowien Ni steel. Thus, it could be possible that the original Bowie knife was made of pretty good Ni steel.


    Conclusion

    My study suggests that, as Paul Wellman’s story tells, it could be possible that James Black achieved superior mechanical properties for Bowie knife by melting mixture of steel and meteorite in crucible.

    http://www.juhaperttula.com/
     
  2. Alberta Ed

    Alberta Ed

    Jun 29, 1999
    Sounds speculative, like Excalibur.
     
  3. Juha Perttula

    Juha Perttula Basic Member Basic Member

    79
    Mar 27, 2013
    Yes, surely it is speculation. James Black kept his process a secret, and when he was willing to reveal it, he did not remember it any more. Jim Bowie died in the Battle of the Alamo and his knife got lost. So, we have more stories about the metallurgy of Bowie knife than facts, but sometimes stories are more important than real historical facts.
     
  4. Twindog

    Twindog Gold Member Gold Member

    Apr 6, 2004
    Thank you for the great experiment.

    Could extended hand forging have removed more of the impurities, such as the sulphur? Obviously, adding a meteorite to steel would also add a lot of impurities to that steel, relative to primitive carbon steel; so maybe the smith would go to greater lengths to remove impurities.

    I tend to presume that most of these legends are really myths, but it's interesting to see that they could be true, depending on circumstances.
     
  5. Juha Perttula

    Juha Perttula Basic Member Basic Member

    79
    Mar 27, 2013
    Forging fragments and elongates slag and impurity particles and in that way makes them less harmful. If steel has a lot of slag, forging may also drive some slag out of the steel. This is the case when steel is direct reduced from iron ore without melting, for instance the Japanese traditional sword steel. But when raw materials are melted in crucible slag floats and steel is quite pure from slag inclusions, and in this case, forging can not further reduce slag content.

    The problem with crucible steel is P and S impurities, because free P and S atoms can travel in steel matrix. They always migrate into grain boundaries. Forging and heat treatment produce new grains, and the new boundaries are contaminated with P and S. Thus, in old times it was important to use pure raw materials.

    Ancient smiths were able to remove S from steel, because when iron ore was heated S burned and SO2 fumes escaped. Thus, ancient steels often had less than 0.01% S. The P content of steel mainly depended on the P content of iron ore. The P content of ancient blades typically ranged between 0.01% and 0.5%. Sources of pure iron ore were known, for instance Swedish ore, and when needed, pure steel was available in old times.

    Meteorites were more complicated. Blacksmith can remove large FeS inclusions and got S content of about 0.01%, but only less than one meteorite of ten have less than 0.05%P. So, meteorites were generally dirtier than steel.

    I have studied meteorite statistics and documents and my draft estimation is that about 100 tonnes of meteorite iron are used by blacksmiths. Most of meteorites are used in prehistoric times.
     
  6. mete

    mete Gold Member Gold Member

    Jun 10, 2003
    DocJD likes this.
  7. Cobalt

    Cobalt Gold Member Gold Member

    Dec 23, 1998
    Interesting theory. If the story is actually true. That is a big IF. But it is cool regardless. One thing is for sure, that at best the meteorite added low amounts of alloying elements, like you see in some of the modern tough steels.
     
  8. Juha Perttula

    Juha Perttula Basic Member Basic Member

    79
    Mar 27, 2013
    Interesting link, we have good evidences that man used meteoric iron during Bronze Age. But we can also assume that meteoric iron was used during Neolithic Stone Age despite archaologists do not know very ancient meteoric Stone Age artefacts. But at 1800's, indigenous people of Greenland, Inuit, still lived in Stone Age, and they utilized meteoric iron. They had sources tens of tons meteoric iron, which they had had utilized since time immemorial. Unfortunately Robert Peary stole their material and sold it to American Museum of Natural History.

    Wikipedia also knows this meteorite https://en.wikipedia.org/wiki/Cape_York_meteorite
     
  9. Cobalt

    Cobalt Gold Member Gold Member

    Dec 23, 1998
    One thing about meteorites is that there is no unknowns in them. If you smelt a meteorite, you get metals that are all found on earth, which makes sense. What made the difference is that you do not have to mine for it, it is just there for you to use. But most iron meteorites are mostly iron, nickel and small amounts of cobalt. The rest of the metal makeup is in ppm which is tiny. So nothing unusual at all
     
  10. Juha Perttula

    Juha Perttula Basic Member Basic Member

    79
    Mar 27, 2013
    The biggest difference, from view point of bladesmith, between meteoric iron and ore base steel is nickel concentration. No meteorites have less than 5% Ni and very few meteorites have more than 20%. Generally iron ores contain about 0.01%Ni, but some iron ores have Ni content up to 2%. For instance Mayari steel from Cuba at the beginning of 1900's naturally contained 1.5%Ni and 3%Cr.
     
    Last edited: Dec 6, 2017
    Cobalt likes this.
  11. mete

    mete Gold Member Gold Member

    Jun 10, 2003
    When as a youngster you can see and touch the meteorite , as I did many times, it puts a different meaning to it !! We call it the " WOW Factor " ! :D I wonder if that pushed me toward being a metallurgist .
     
    Juha Perttula likes this.
  12. Cobalt

    Cobalt Gold Member Gold Member

    Dec 23, 1998
    very true. Most are closer to 8% Ni. I guess the question becomes how much of the knife was made from a meteorite?
     
  13. deltaboy

    deltaboy

    Jul 6, 2014
    Thanks the Original Bowie was a Special knife!
     
  14. Juha Perttula

    Juha Perttula Basic Member Basic Member

    79
    Mar 27, 2013
    This is a good question. Now we know amount of few hundred tons of iron meteorites. We can assume that earlier generation have found and used about 100 tonnes of iron meteorites. Meteoric iron was expensive and for that reason, I think, they favored small blades. I assume that the weight of on average blade was 100 g. Then we can calculate 1 000 000 blades.
     
  15. Cobalt

    Cobalt Gold Member Gold Member

    Dec 23, 1998
    In my opinion, the fact that such a big deal was made of the use of a meteor to me means that a major part of the steel was from the meteor. Maybe 50%? who knows. But if it was a small portion, no one would have mentioned it IMO. So my guess is at least half if not more.
     
  16. mete

    mete Gold Member Gold Member

    Jun 10, 2003
    Today much of meteor iron has a Widmanstattin structure which is considered decorative. Heating Widmanstattin will destroy the structure !
     
  17. Cobalt

    Cobalt Gold Member Gold Member

    Dec 23, 1998
    But you don't have a choice since you cannot recreate it(widmanstatten), or at least I don't think you can?
     
  18. mete

    mete Gold Member Gold Member

    Jun 10, 2003
    I don't know about you Mr Cobalt but I made it, without even trying in freshman metallurgy !! :p :rolleyes: :rolleyes: I had a photo of it ,if I could find it , unless it was eaten by the computer Grinch. In any case it was a simple iron-carbon alloy. The interesting structure was precipitation along specific crystal planes . The professors freaked out - how did you do this ?? "
     
    Cobalt likes this.
  19. Cobalt

    Cobalt Gold Member Gold Member

    Dec 23, 1998
    What did you do, slow cooling from molten to 0 kelvin in a week?:D
     
  20. Juha Perttula

    Juha Perttula Basic Member Basic Member

    79
    Mar 27, 2013
    Here is a photo of my piece of Gibeon meteorite and its Widmanstatten structure
    Gibeon400.JPG
    It is result of Ni segregation during very slowly cooling perhaps about one degree per million years. Etching reveals different Ni contents. It is misconception that heating destroys the structure, of course melting destroys the structure, but not forging heat. However, forging elongates material and distort the Widmanstatten structure. In my opinion the figures of forged meteorite are not very beautiful, Damascus steel looks better. Perhaps this was the reason why Indonesians made their traditional Kris blades of Damascus steel which was made by laminating nickel containing meteoric iron and ore based steel. Notice how UNESCO recognize the Indonesian Kris https://ich.unesco.org/en/RL/indonesian-kris-00112
     

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