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Thread: modern wootz and best, antique wootz ever

  1. #26
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    ok..

    then your experiment should be a good one.. and i'm sure there is alot of people that will like to see the results..
    - with decent micrographs of the structures.. ... not just hardness tests.. ( that tells me very little )

    make sure you have some shamshir with what resembles a HAZ at the ricasso area.... which could possibly indicate they were oil or water quenched
    -- not just samples of what seem to be edge quenched blades..
    --



    - and ofcourse it makes a difference if its a rehilted blade.... lots of people assume the blade comes from a certain area based on the hilt..... what if there is a regional difference in how these blades are made... ?

    if you only examine the same old stuff, from the same old area.... . aren't you going to get the same old results !!!


    i hope your not basing your ideas on Persian Culture on stuff you have seen in India.. how does that make sense ???


    anyhow... this is going nowhere..

    G

  2. #27
    Just to throw an extra variable into the mix...

    In many of my ingots, there is a distinct segregation vertically within the ingot, which is to say that the lower third of the ingot is visibly different than the upper portions. My ingots also tend to have a distinctly more crumbly area in the top/middle of the ingot, but this I have always assumed is the last area to solidify and therefore gets all the "nasties".

    The vertical segregation is a mystery to me however, and is of possible interest here because this segregation remains visible in the final blade. If the ingot is forged out in the accepted manner (sides of the ingot become flats of the blade, top of ingot is spine of blade) this line runs along the edge and is more or less visible from blade to blade. I am not saying that this is the cause of the dark edges that folks have been describing, but tossing the idea out there to see what people think.

    Another variable that comes to mind is the koftgari decoration that is almost ubiqitous on Middle Eastern blades. There was recently a thread on the art here on the forums, and it was clearly stated that the final process of fixing the gold/silver to the steel involved heating...I believe the temperature in question is somewhere in the 650-900F range. So even if a blade had been quenched and tempered, it was going to be REALLY tempered in that area after the koftgari was finished. This does also raise the question of whether koftgari can even be applied to hardened steel...any ideas on this? Many of the finest examples of wootz and laminated blades from the Middle East also have extensive carving work that I have assumed was chiseling followed by planishing or polishing. When in the process would this have been done?

    Last question for today: can a carbon steel even partially harden in an air-blast quench? If any part could harden at all, it would be the edge.

    Last bit of speculation for today: a change in the color and properties of wootz could occur simply by getting the edge slightly hotter than the body during whatever HT was used, since more carbon would go into solution...fewer/smaller carbides=darker material.

  3. #28
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    Quote Originally Posted by Greg T. Obach View Post
    i hope your not basing your ideas on Persian Culture on stuff you have seen in India.. how does that make sense ???
    G
    I can only speak of what I have seen...most of the arms I saw in India were Indian, but a lot was Persian. I can tell the difference most of the time
    There was always trade and migration of peoples and war booty....how else could an assadallah blade end up on a shelf in Sturgeon Bay, WI?

    And I think this discussion is going somewhere.

    Ric
    Richard Furrer
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  4. #29
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    Quote Originally Posted by Greg T. Obach View Post
    ..............
    most of the shamshir i've handled are oil quenched.... not all of them but most.... some with a very clear HAZ at the ricasso area... .. one actually went right through the cartouche.. .. this has happened often enough to be obvious that there is more going on than just air quenching......

    G
    What exactly is a HAZ, Greg?

    Great discussion BTW!
    "If metal can be polished to a mirror-like finish,
    What polishing might the Mirror of the Heart require"

    Rumi

  5. #30
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    Quote Originally Posted by MumtazB View Post
    What exactly is a HAZ, Greg?

    Great discussion BTW!
    I believe he means "Heat Affected Zone". Which in modern welding terms means the heat bleed over from the bead of weldment and its affects on the metal near that weld.
    In this case it is referring to the resulting structures from the heat treatement...whatever those structures may be.


    Ric
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  6. #31
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    Thanks for that Ric.
    Many shamshir in Manoucher's book display some sort of HAZ at the edge I think
    "If metal can be polished to a mirror-like finish,
    What polishing might the Mirror of the Heart require"

    Rumi

  7. #32
    That must have been a wonderful day at the museum(s), Ric! I look forward to reading the publications that come out of it, and to the data on your collection as well.
    I am willing to take the x-ray diffraction report of martensite and the anecdotal evidence of hard edges as semi-proof that wootz was sometimes queched in accordance with historical accounts, and I don’t think I will look too foolish when you get your micrographs done.
    The mill ball thing was mostly wishful thinking, but a large component may be that many people (dealers, collectors) had only heard of steel dendrites in connection with wootz; so when handed a lump of dendritic steel it was easy to believe it was an ingot, despite the lack of ingot features. Now that it is common knowledge that all iron alloys solidify with dendritic structure it is less likely that random lumps of steel will be accepted as ingots.

    How many times has the account been transcribed/translated during the 1000 years since al Biruni first witnessed the process? I am not sure, but I assume that a lot has been lost or changed in between.


    Ah, you are in luck – al Kindi and al Biruni have recently been newly translated, in an edition that gives you photos of the original manuscripts (so you can puzzle out the 9th & 10th century Arabic yourself, if you feel so inclined) as well as word-for-word translation into English and expert interpretation (so you can judge if the interpretations are accurate for yourself, and disagree if you feel more expert). Way better than reading summaries of interpretations of translations of the historical accounts, like Figiel and Sachse, which are less trustwotrthy for sure.
    Medieval Islamic swords and Swordmaking
    by Robert Hoyland and Brian Gilmour
    ISBN-13: 978-0-906094-52-5
    ISBN-10: 0-906094-52-6
    http://www.oxbowbooks.com/bookinfo.c.../Location/DBBC

    I guess another reason I find historical accounts of wootz manufacture suspect is that it has been phenomenally hard to reproduce the results. If the recipes that exist are truly accurate, why has everyone who has tried to reproduce the stuff met with middling results at best?


    I’m not aware of a single person who is seriously trying to duplicate the original recipies – the end chemistry yes, starting materials and method no - but the real problem here is that we have gone through the industrial revolution and come out the far side without the ability to comprehend basic raw materials processing on an individual level, the loss of handed-down institutional knowledge is just the tip of that iceberg. Ten individuals working on a problem for ten or twenty years cannot hope to recoup the millennia of slowly accreted knowledge that were lost in the last two hundred years, without an awful lot of luck.

    Regarding koftgari, you can get the gold and steel to exchange electrons by burnishing at 600 + degrees F, but it is not necessary – the gold will stick just fine without heat if your crosshatching is good. I suspect blades that were made for use would not have been de-tempered during decoration.
    vikingswordsmith.com

  8. #33
    Jeff, Thanks for the info on that book. I will have to get a copy. I have been somewhat remiss in my reseach of late, and this will be a good way to get started again.

  9. #34
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    Thanks for the book reference Jeff. I'll have to buy that one
    "If metal can be polished to a mirror-like finish,
    What polishing might the Mirror of the Heart require"

    Rumi

  10. #35
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    Hello All,
    I just read the article Greg sited.....Journal of the history of Arabic science vol 1, 1978 pg 3-30 " Metallographic examination of Two Damascene steel blades" by Jerzy Piaskowski

    The Vickers hardnesses averages given are 348 for blade one and 366 for blade two...... oddly enough that is still within the range of the blades tested in India and well within the fine pearlite range of hardnesses.
    I will say that Martensite will get that soft from roughly 1000-1100F tempering, but I believe that the author used sorbite to mean pearlite.

    It was also stated that there was a slag inclusion on the spine of one of the blades (centered and running with the blade)...identified by the author as possible poorly melted bloomery iron from the charge material OR as possible shrinkage cavity from the top of the ingot.

    It was of course from the ingot top which has all the flux,dross and poorly solidified "junk" from the melt...it is common, as has been stated by others in this thread, to see such on the spine of blades and no doubt we have all seen it in our own blades....maybe on the cutting edge if you forged them "the wrong way" as I did my first few times over a decade ago.

    The author has the material surrounding this "non-metallic" inclusion as ferrite and as one moves from this he sees sorbite and then for the rest of the blade sorbite and cementite...from this I draw the assumption that the decarb has left only iron near the inclusion and as you get further away there is enough carbon to form pearlite and finally cementite (carbide).
    So if the blade was indeed martensite (read as sorbite) then the blade was full hardened through the entire cross-section so as to have the sorbite even to the interior of the spine surrounding this inclusion.
    I do not see this as the case with vickers hardnesses at such levels.

    Wootz is low hardenability material and though it is possible to through harden a blade section it is less likely that that same section could be evenly heated to 1000-1100F from edge to spine and held long enough to temper evenly to show three vickers hardnesses at three places on the blade reading the same numbers.
    Possible, but not likely in my opinion.
    I believe that discussions such as this is why Sorbite is no longer used as a term to define anything...its use was/is confusing.

    Greg, this is not a personal attack on you, the author or anyone else....I am after information and data....and from what little I understand about metallurgy the assumption of martensite in these blades from the article is not supported.
    Often what we "know" to be true, what we "believe" to be true and what we can "prove" are not the same ting.

    Ric
    Richard Furrer
    Sturgeon Bay, Wisconsin
    http://doorcountyforgeworks.com/

  11. #36
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    thats your opinion ......not mine..

    it maybe that this is pearlite.. or not.. but you still did not change the possibility that its a highly tempered martensite ... nor discount that the quenching description he chose to refer to

    massalski account :

    " When the blade has cooled, it is quenched in boiling hemp seed oil. Some armourers add a little grease and bone marrow. The wooden tub which contains the oil is sufficiently large for the blade to go in easily. The oil is heated by plunging two or three pieces of red hot iron into it. During this time the blade is given a heat between red and white hot, and then plunged into the bath. If it is a dagger it is held flat; if it is a sabre, it is quenched little by little, beginning by the end of the cutting edge, holding the latter toward the bath. This manoeuvre is repeated untio the oil stops smoking, which proves that the blade has cooled. After quenching the blade is always soiled with burnt oil. This dirt is removed by heating it enough to set light to a piece of wood, and by rubbing with a rag from a bedsheet. It is at this time too that imperfections are corrected and the blade is straightened if it is out of true. After 5 or 6 heats the blade leaves the fire quite ready, i.e it then only has to be cleaned with sand, polished with emery and mottled by pickling in iron sulphate. "

    -- sounds like highly tempered martensite to me.. ???



    ... rather you go on the traditional assumption that its pearlite.....



    and i don't take this as a personal attack.. ... if i'm wrong then i'm wrong... it does happen alot



    Greg

  12. #37
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    Quote Originally Posted by Greg T. Obach View Post
    thats your opinion ......not mine..

    massalski account :

    " After quenching the blade is always soiled with burnt oil. This dirt is removed by heating it enough to set light to a piece of wood, and by rubbing with a rag from a bedsheet. It is at this time too that imperfections are corrected and the blade is straightened if it is out of true. After 5 or 6 heats the blade leaves the fire quite ready, i.e it then only has to be cleaned with sand, polished with emery and mottled by pickling in iron sulphate. "

    -- sounds like highly tempered martensite to me.. ???

    Greg
    OK, Lets go with this then.

    The Massalski account ..by stating "heating it enough to set light to a piece of wood" could mean that the oil is flamed off and there is an active fire of burning oil on the blade OR that the sword is heated till it is hot enough to set a piece of wood on fire by touching it to the blade.

    Which do you think he meant?

    Ric
    Richard Furrer
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    http://doorcountyforgeworks.com/

  13. #38
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    why would there be second heat treat after the quench... are you thinking that they are tempering the pearlite ?

    for that matter why even quench in oil if you trying to create pearlite..

    these old accounts are not rock solid in their descriptions but you can reason what they were doing from the main points... ... if it walks like a duck ........ then ............

    the other accounts, where they were setting up pearlite its obvious they were clearly doing so.. ( quenching in a strong wind from a crack in a wall ...or giving the sword to a horserider to cool it ).

    and i don't recall a secondary tempering of pearlite in these cases.... ?...


    Greg

  14. #39
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    Quote Originally Posted by Greg T. Obach View Post
    why would there be second heat treat after the quench... are you thinking that they are tempering the pearlite ?

    for that matter why even quench in oil if you trying to create pearlite..

    these old accounts are not rock solid in their descriptions but you can reason what they were doing from the main points... ... if it walks like a duck ........ then ............

    the other accounts, where they were setting up pearlite its obvious they were clearly doing so.. ( quenching in a strong wind from a crack in a wall ...or giving the sword to a horserider to cool it ).

    and i don't recall a secondary tempering of pearlite in these cases.... ?...


    Greg
    I am not thinking anything...just trying to figure out Massalski's meaning...the burning of the wood....could mean two things and therefor two temperatures as a result.

    I have "floor cooled" some wootz I made...not as dramatic as a horse ride, but there is a wind in my shop..and not just after I eat beans....the resulting hardness was 32 Rockwell C...roughly 318 Vickers.....what species of duck are we talking about?

    I will write to Prof Piaskowski in Poland and see if he will lend me those samples.


    Oh, I flashed some olive oil on my thermocouple this afternoon....it smoked at about 450F and flamed at about 630F and with a continuous drip of oil down the thing it burned at 905F for about three seconds. I should have set up a wick lamp, but I do not have the time. My thermocouple is 3/16" diameter and I preheated to get close to the valuses I expected to shorten the response time. There is a time lag from heat to registration of the heat, but not much and my TC is calibrated so its within 15F or so...my eyes were dancing from TC to computer, but these were the results I saw.
    I do not know the flash point of hemp seed offhand..internet says 285F, but that seems low to me. The temps are in the ballpark, but the heat time is short...a few seconds.
    If the blade were placed in a vat of flaming oil then there may be enough time to temper.
    I am still trying to find the corelation between 340-360 Vickers and martensite....the quench and temper seems off to me to get those results......then again we do not have one of the blades Massalski saw quenched to test.

    I am still not convinced.
    Ric
    Richard Furrer
    Sturgeon Bay, Wisconsin
    http://doorcountyforgeworks.com/

  15. #40
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    hi

    i don't expect you to be convinced.... matter of fact, i really like that your putting this study to the task... .. and corresponding with the author for clarification is a very good idea.... if this does work... then at least we won't be in the dark about these particular swords in this study....

    theres lots of questions to be answered...... and i'm sure it'll take awhile to figure it out


    Greg

  16. #41
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    Quote Originally Posted by Greg T. Obach View Post
    hi



    theres lots of questions to be answered...... and i'm sure it'll take awhile to figure it out


    Greg
    Not really Greg...should take about 30 seconds under a microscope.

    Ric
    Richard Furrer
    Sturgeon Bay, Wisconsin
    http://doorcountyforgeworks.com/

  17. #42
    Couple things I noticed about the account. First, the blade is heated to between a red and a white heat. If I brought my wootz blades up to a white heat before quenching, I don't think there would be much pattern left to speak of...not to mention the horrible structures that would result from a white-heat quench. After a few centuries of making wootz blades, I would think they would have narrowed the range down a bit more than "between red and white".

    Second, the account refers to "5 or 6 heats" in what could be called the tempering cycle, but which is being used here to remove the excess oil and solids. Ric, I noticed that you worked out temperatures for setting the oil alight; do you have any figures for the burn-off temp of partially burned oil and solids? What about the flame temp for wood, since the blade is supposed to be hot enough to set would alight as well. My gut feeling is that this will be a higher temperature, and therefore a softer temper. Added to the 5-6 heat cycles, this could account for the very soft readings...if we are assuming a quench and temper technique, which doesn't seem like a proven thing at this point.

    I guess another question here, and this may be a stupid one, is how much it really matters whether it is pearlite or martensite if the hardness values are the same? Will the two behave very differently after being "tempered" at 1000-1100F as per Greg's suggestion? I have never tested a blade that had been tempered this high (regardless of quench technique), but my gut feeling is that martensite tempered to that degree would be darn close to annealed.

    On a different subject, I am not sure how there could possibly be ferrite anywhere in a wootz blade (other than in the cementite/ferrite mix for pearlite), since during the forging there should be a complete evening out of carbon. Are we assuming that the cracking is allowing additional oxygen contact along slag inclusion and this is continuously robbing carbon from the surrounding material? Or is there another element present in the material that is preventing the carbon migration to this area. I know that nickel will block carbon...will sulfur or other impurities do the same?

    Lastly, did anyone catch the thread in the general discussion forum about the Kindjal that Kirpichev has made recently? The pictures of the blade are not great, but the pictures of the blade in process are interesting. First, the original ingot (although no itself pictured) appears to have been an unusual shape, perhaps rather square rather than mushroom-cappish. I have considered doing this myself, since squared ingots are much easier to forge, and less prone to cracking due to more even material movements. In casting silver ingots, the mold is always squared rather than round, since it is almost impossible to roll or forge down a round ingot without it cracking in the center...any thoughts? The pictures also seem to imply that the forged ingot was cut, restacked, and forge-welded before being drawn out into a blade. I feel as though I read about this being done by some of the ancient smiths, but has anyone seen evidence of it actually being done? In my experience, a forge weld (other than the modern boxed welds) is always visible to some degree, and I would think that such a line would be very hard to miss in a blade. I have definitely seen wootz blades that were scarf welded from two shorter pieces, but haven't had a chance to examine enough blades to know if laminated wootz blades exist. I would think that it must be a tricky affair, since the carbon level dictates extremely careful temperature control. It occurs to me that Kirpichev could be using a lower carbon mix for his bulat, since the high carbon levels are not necessary to develop the pattern, just necessary to develop the pattern in the traditional fashion.

    Enough of my novel.

  18. #43
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    testing

    Quote Originally Posted by Peter T. Swarz-Burt View Post
    Couple things I noticed about the account. First, the blade is heated to between a red and a white heat. If I brought my wootz blades up to a white heat before quenching, I don't think there would be much pattern left to speak of...not to mention the horrible structures that would result from a white-heat quench. After a few centuries of making wootz blades, I would think they would have narrowed the range down a bit more than "between red and white".

    ******
    Yes...but old accounts are often like this...the information has to be viewed with a critical eye, but yet one can not discount the outragous...till it is tested.
    Ric
    *********
    Second, the account refers to "5 or 6 heats" in what could be called the tempering cycle, but which is being used here to remove the excess oil and solids. Ric, I noticed that you worked out temperatures for setting the oil alight; do you have any figures for the burn-off temp of partially burned oil and solids? What about the flame temp for wood, since the blade is supposed to be hot enough to set would alight as well. My gut feeling is that this will be a higher temperature, and therefore a softer temper. Added to the 5-6 heat cycles, this could account for the very soft readings...if we are assuming a quench and temper technique, which doesn't seem like a proven thing at this point.
    ******
    The Massalski account ..by stating "heating it enough to set light to a piece of wood" could mean that the oil is flamed off and there is an active fire of burning oil on the blade OR that the sword is heated till it is hot enough to set a piece of wood on fire by touching it.

    Assuming the first then the temps reached needs to hit the 1000F level long enough to effect a temper. I can not find any charts for open burning temp of hemp seed oil, but I will run a test with my thermocouple to see at what temp my quench oil burns. Not a direct correlation, but it may put the number close.

    For the second the temps for igniting wood, according to the National Forest Products lab, are 806F (430C) with exposure times at that temp of 0.3 seconds at temp for spruce and Fir and 0.5 seconds for long leaf maple.....so the blade will have to keep its heat long enough to do this or be hotter than this.

    So, the numbers may work out for highly tempered martensite....1000-1100F to get the 330-360 Vickers numbers. But without tests the most likely is for pearlite on the tset blades discussed here.
    Ric


    ********

    I guess another question here, and this may be a stupid one, is how much it really matters whether it is pearlite or martensite if the hardness values are the same? Will the two behave very differently after being "tempered" at 1000-1100F as per Greg's suggestion? I have never tested a blade that had been tempered this high (regardless of quench technique), but my gut feeling is that martensite tempered to that degree would be darn close to annealed.

    *******
    Gee, good question....I answered this when a Northwestern student did bend tests on some of my wootz and old wootz in 2001. The report was online, but has been removed by the Univ...I have the results here in a paper and will place it back online when I have the time.....

    basically what you see is less bend, but higher pressure required to break the material......all the samples did break however...including the old wootz.

    BUT, we should not ask if there was benefit, but if it was, in fact, done that way...was historically accurrate? Was that the method used?
    Which, by thae way is why I have issues with chemistry outside old wootz being called wootz today....drill bits included.

    Ric
    ******************
    On a different subject, I am not sure how there could possibly be ferrite anywhere in a wootz blade (other than in the cementite/ferrite mix for pearlite), since during the forging there should be a complete evening out of carbon. Are we assuming that the cracking is allowing additional oxygen contact along slag inclusion and this is continuously robbing carbon from the surrounding material? Or is there another element present in the material that is preventing the carbon migration to this area. I know that nickel will block carbon...will sulfur or other impurities do the same?

    ******
    Recarbing a decarb is not a simple thing......L.S. Darken whote about this in the 1950's? in his work...he never found the mechanism.

    Also there may be enough slag inclusions at the top of the ingot to prevent carborization...like in some areas of wrought iron.....OR....perhapse there are other elements blocking such.....

    Simple question...complicated answer

    Ric
    **************

    Lastly, did anyone catch the thread in the general discussion forum about the Kindjal that Kirpichev has made recently? The pictures of the blade are not great, but the pictures of the blade in process are interesting. First, the original ingot (although no itself pictured) appears to have been an unusual shape, perhaps rather square rather than mushroom-cappish. I have considered doing this myself, since squared ingots are much easier to forge, and less prone to cracking due to more even material movements. In casting silver ingots, the mold is always squared rather than round, since it is almost impossible to roll or forge down a round ingot without it cracking in the center...any thoughts? The pictures also seem to imply that the forged ingot was cut, restacked, and forge-welded before being drawn out into a blade. I feel as though I read about this being done by some of the ancient smiths, but has anyone seen evidence of it actually being done? In my experience, a forge weld (other than the modern boxed welds) is always visible to some degree, and I would think that such a line would be very hard to miss in a blade. I have definitely seen wootz blades that were scarf welded from two shorter pieces, but haven't had a chance to examine enough blades to know if laminated wootz blades exist. I would think that it must be a tricky affair, since the carbon level dictates extremely careful temperature control. It occurs to me that Kirpichev could be using a lower carbon mix for his bulat, since the high carbon levels are not necessary to develop the pattern, just necessary to develop the pattern in the traditional fashion.

    ******
    I have seen Kamara blades where wootz was on one side and bloomery steel on the other.we tested on in India...350 viskers on the wootz side and 250 on the bloomery..riddle me that Batman...sort of shows what I have been saying...it was not "quenched" in the modern sense.....or severly tempered...which deos not seem likely as there is no eveidence for this in the form of martensite in the microgaph.

    As to square ingots...what about solidification and such...would alter the pattern a bit...at least in my tests it did..I've made all sorts of shapes.....

    Re-welding wootz...it can be done, but the kamara blade mentioned above showed a little line and that was all.......I have only seen the lap/scarf weld in the joint of two ingots..some with a larger black line that others, but I have not seen one which showed a seam along the edge/spine as in "normal" welding.

    We tested one such weld in that Northwestern papre and it was only a few foot pounds weaker and a few fractions of an inche less "bendy" than the blade just beyond the weld.so...no loss of function for the scarf
    Ric
    ***********

    Enough of my novel.
    Just adding to your novel Peter.
    Ric
    Richard Furrer
    Sturgeon Bay, Wisconsin
    http://doorcountyforgeworks.com/

  19. #44
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    Hi

    the account does have its problems... as most old accounts do.... ( maybe in translation )

    but it does head in a general direction ... .. as i have said before .....it seems like alot of trouble to set up pearlite... i guess those old smiths like to do things the long and hard way ... almost like some bizarre ritual... ... i guess in this case they didn't believe in the kiss principle..

    seriously.... quenching in oil... reheating the blade after.. several times... also it didn't say if that wood was a piece of green wood.....which is harder to lite..



    i do own a lap welded tulwar and it is functional.... and you can easily see the weld marks when its etched.. .. i think that these blades weren't made to be etched ...more along the lines of a general infantry weapon...
    -- the lap on mine in right in the middle... so i'd imagine that would be a bad place to put it if it was weak..

    the solidification structure should have some influence on the pattern.. .. but how much it affects the outcome is a good question..

    I've stayed with the same kind of crucibles all along.. and the patterns change from ingot to ingot.. ... its hard to say
    - also i've cut ingots in half and forged out... with similar results

    there are lots of factors that affect the forgability of these ingots..... for my self i found the long thermal cycles/roasting after the ingot is made...helped alot with success and pattern..
    -

    Greg






    Quote Originally Posted by Peter T. Swarz-Burt View Post
    Couple things I noticed about the account. First, the blade is heated to between a red and a white heat. If I brought my wootz blades up to a white heat before quenching, I don't think there would be much pattern left to speak of...not to mention the horrible structures that would result from a white-heat quench. After a few centuries of making wootz blades, I would think they would have narrowed the range down a bit more than "between red and white".

    Second, the account refers to "5 or 6 heats" in what could be called the tempering cycle, but which is being used here to remove the excess oil and solids. Ric, I noticed that you worked out temperatures for setting the oil alight; do you have any figures for the burn-off temp of partially burned oil and solids? What about the flame temp for wood, since the blade is supposed to be hot enough to set would alight as well. My gut feeling is that this will be a higher temperature, and therefore a softer temper. Added to the 5-6 heat cycles, this could account for the very soft readings...if we are assuming a quench and temper technique, which doesn't seem like a proven thing at this point.

    I guess another question here, and this may be a stupid one, is how much it really matters whether it is pearlite or martensite if the hardness values are the same? Will the two behave very differently after being "tempered" at 1000-1100F as per Greg's suggestion? I have never tested a blade that had been tempered this high (regardless of quench technique), but my gut feeling is that martensite tempered to that degree would be darn close to annealed.

    On a different subject, I am not sure how there could possibly be ferrite anywhere in a wootz blade (other than in the cementite/ferrite mix for pearlite), since during the forging there should be a complete evening out of carbon. Are we assuming that the cracking is allowing additional oxygen contact along slag inclusion and this is continuously robbing carbon from the surrounding material? Or is there another element present in the material that is preventing the carbon migration to this area. I know that nickel will block carbon...will sulfur or other impurities do the same?

    Lastly, did anyone catch the thread in the general discussion forum about the Kindjal that Kirpichev has made recently? The pictures of the blade are not great, but the pictures of the blade in process are interesting. First, the original ingot (although no itself pictured) appears to have been an unusual shape, perhaps rather square rather than mushroom-cappish. I have considered doing this myself, since squared ingots are much easier to forge, and less prone to cracking due to more even material movements. In casting silver ingots, the mold is always squared rather than round, since it is almost impossible to roll or forge down a round ingot without it cracking in the center...any thoughts? The pictures also seem to imply that the forged ingot was cut, restacked, and forge-welded before being drawn out into a blade. I feel as though I read about this being done by some of the ancient smiths, but has anyone seen evidence of it actually being done? In my experience, a forge weld (other than the modern boxed welds) is always visible to some degree, and I would think that such a line would be very hard to miss in a blade. I have definitely seen wootz blades that were scarf welded from two shorter pieces, but haven't had a chance to examine enough blades to know if laminated wootz blades exist. I would think that it must be a tricky affair, since the carbon level dictates extremely careful temperature control. It occurs to me that Kirpichev could be using a lower carbon mix for his bulat, since the high carbon levels are not necessary to develop the pattern, just necessary to develop the pattern in the traditional fashion.

    Enough of my novel.
    Last edited by Greg T. Obach; 03-01-2008 at 10:24 AM. Reason: needs some

  20. #45
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    why go to the effort of setting up highly tempered martensite..

    I'm not sure of the performance end of the steel at that point... but what i'm well aware of is the response of wootz when you go to restore and etch a blade.... especially the color of the watering and the darkness....

    a pearlite blade etches very litely and much slower... .. and can sometimes be very troublesum to get a nice pattern..

    with a quenched blade.. it will etch quickly .. and respond very nicely in the same solution.... the watering will be nice and dark... which gives a good contrast to the carbides..

    these blades were valued for their beauty... so this would be a possible reason to go to this kind of structure

    Greg

  21. #46
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    Greg,
    So the blade etches better when quenched...and yet your lap welded blade was not meant to be quenched so pattern was not important? I'm confused. I saw about 30 lap welded wootz blades while in India, that were etched, unknown how many were not etched...as the only way to see that would be in correct light. There was an entire museum where all the blades were burnished bright...I saw pattern on only one of them, but no doubt most of the others were patterned in some way, just not visible.

    I am still looking for a micrograph of martensic wootz...it was not present in the article you sighted...or did I miss it in the micropghaphs the author included?

    As to function....I wondered about some of the other pattern-welded patterns (non-wootz) as far as function; like that Indian "V" Chevron...so I made one and bent it...held well. Brings credit to the makers I think in that what they made, no matter how pretty, actually functioned.

    Ric
    Richard Furrer
    Sturgeon Bay, Wisconsin
    http://doorcountyforgeworks.com/

  22. #47
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    sorry for the confusion..

    i was mentioning different points.. the lap welded blade i own is an Indian tulwar.. .. and it doesn't appear to be quenched..
    - my comment was just to testify that the lap welds are usually obvious to see...
    - and I think that not all steels were made to be etched or pattern brought out.... as a lap weld can look very unsightly


    test it out for yourself......... take a piece of wootz and quench only half in in oil.... does the martensite etch faster or does the unquenched side... its a simple test..


    the study doesn't have clear micrographs.... but at the same time it doesn't show micrographs of pearlite either..... there is just the testimony and description by a well known author and a clear reference to the process to remake the structure in the wootz blades..

  23. #48
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    who knows all the variables...

    ...in how these patterns emerged. Supposedly the makers would sometimes take the crucible out and listen for a "sloshing sound"...part of it could be in the way they sloshed it around, who knows...
    My persian jambiya has a beautiful pattern which came out easilly even with a quick dilute FeCl wipe. It etched darker at the edges, which I take it to mean that something either intentionally or not happened at the cutting edges. Could be as simply as the thinner metal cooling faster after the last heating- the blade steel tested at only about 30RC near the mid-rib.
    And no, nobody's getting my jambiya for destructive testing, had to go through too much to get it...would have missed out except the other guy who was thinking of getting it at the bazaar thought the handle was too plain, and settled for one with a silver grip and a blade that, while once a beautiful kirk narduban pattern was three-quarters destroyed by corrosion...

  24. #49
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    Some photos...

    ... of my jambiya, and apologies for the bad shots. I'm not a great photographer and I'm using a relatively cheap digital camera.
    Attached Images Attached Images    

  25. #50
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    Fine piece there Al. I'd to a blade with a mid-rib like that sometime
    Last edited by MumtazB; 04-08-2008 at 08:55 AM.
    "If metal can be polished to a mirror-like finish,
    What polishing might the Mirror of the Heart require"

    Rumi

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