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Thread: Wootz/Pulad Old Recipes

  1. #51
    Just wanted to follow up on something said a while back in the thread...

    Greg, I wonder whether a big part of the difference in appearance between the pattern in antique wootz and say, W-2, comes from the difference in how they are forged out. Wootz is traditionally forged out "sideways", while it is my understanding that modern steel ingots are forged out "vertically". This is the way that I have been forging out many of my ingots, partly because it is less awkward to forge and partly because any cracking I get is int he upper portion of the ingot and forging out vertically makes it easy to cut the cracked parts off. the pattern that I get tends to be more fibrous, with the carbides aligning in strands rather than sheets. I'm posting a picture of a section of an 8" wootz (not W-2) dagger that I am just about finished with. The picture isn't spectacular, but the fibrous nature of the pattern shows up pretty well.

    I also noticed ina different thread that someone offered to bring his hydraulic press over to help forge down your ingots. I just wanted to mention that this may not be a great idea, since my press has been a very mixed blessing when forging wootz. The press is most usefull when the ingot is still bulky, and my experience has been that it is difficult to do the initial forging "gently" enough with a press. I have had several ingots simply tear into chunks when I got a little over-excited with the press in the early stages. I think that the issue is that a forging press puts an immediate chill on the material in contact with the dies. this causes the outer part to not move at all, while the inner portion is squashing like clay. If somebody offered to bring their Chambersburg Utility hammer over to forge out the ingot, that might be a different story.

    I hope the picture came through OK...first time using photobucket and posting pics...

  2. #52
    I don’t play with high-alloy steels, I think it would be weird to bring them into a discussion of old wootz recipes…
    A eutectoid steel has no excess carbide or ferrite, therefore the pattern cannot derive from ferrite/pearlite/carbide banding in a steel of eutectoid composition, is what I was getting at – As you move away from eutectoid, more carbides show up in the plus C direction, more ferrite in the minus C direction, but I don’t think any amount of vanadium will give you visible carbides in a eutectoid or hypoeutectoid steel. I’m no metallurgist, so I could be wrong, but I have noticed that when I make an ingot of hypereutectoid steel the carbides stand out in the etch (I’ve seen this in one of Pendray’s blades as well) and ingots of roughly eutectoid steel have none, even with a strong pattern in the steel. Hence, my suspicion that alloy banding is fundamentally what is going on, and the carbides are a secondary effect applicable to the special circumstances of a very high carbon steel, but not to eutectoid or sub-eutectoid steels...

  3. #53
    pearlite is cementite (iron carbide) and ferrite mixed in a specific ratio. If the blade has pearlite, then it has carbides. Excluding bainite, which I don't know enough about to add it to my statement, cementite is the only form carbon takes in room temperature, un-hardened steel. When we bring a blade up to austenitic, the cementite dissolves and the carbon "goes into solution". Some elements, such as vanadium, hold carbon substantially better than iron does, and the temperature at which these carbides dissolve is substantially higher. When heat-cycling the steel to "bring out" the pattern, we are simply giving these alloys the opportunity to gather as much carbon as possible. In a hypereutecoid steel, this results in actual carbide particles forming in an otherwise pearlitic structure. In hypoeutectoid steels, the vanadiums ability to hold onto carbon better than iron can will result in a greater concentration of pearlite (cementite and ferrite) in some areas than others. This will be just as true in a eutectoid steel. Wherever the vanadium is, there will be more carbides, be they free particles as in hypereutectoid steels or simply the cementite portion of pearlite in hypoeutectoid and eutectoid steels. To say it another way, you don't have to be seeing free carbide particles to be seeing preferential cementite formation in action. As I stated before, the alloy banding is the underlying source of the pattern, but in the alloy amounts that we are speaking of, that banding would never be visible except for its effect on the preferential forming of cementite/carbides in certain areas. The actual carbon content of the steel is essentially moot.

  4. #54
    Join Date
    Aug 2002
    Elliot Lake
    just a quick response..

    i've sometimes quartered an ingot... and got pretty well the same pattern... also... done the same as you mentioned and had no problem with the ingot... as i often get ingots with no air bubbles in the top..... so forging those in any direction wasn't a problem...

    -- you'll find the sheeting in the wootz will orient it's self to the direction of forging.. ( very very bizarre... )...

    -- also.. for this reason i like to forge the blade as close to final shape as possible... because i don't want to necessarily cut across the sheeting at the bevel area.... thats why i'm not a fan of stock reduction of wootz to put bevels in... if you do that.... you cut across the sheeting and get straight lines going across........ not a flowy pattern with nice jelly beaned carbides...

    i still say that theres more than alloy banding at play.... or if its alloy banding , its an industrial strength version compared to the parlor trick wootz you can make with 52100....
    -- if you work in reverse... you can take an annealed piece of 52100 and make up some banding by heat cycling it....

    now... anneal some wootz in the same manner.... can you come up with a wootz type pattern... ... nope... but the V carbides are still there......just small and evenly scattered.. ( i think )

    i'm gonna ramble abit...

    remember that old experiment ..... 1st year university.... bout liquid chromatography ...... put a drop of ink on a paper... then draw a solvent up through the bottom....... it becomes a very large spot with many little rings in it...... ofcourse each ring is made of the different size/shape particles in the ink recipe.... the large particles are close to the center and make up the small rings..... while the smaller particles can move much quicker and form the large outside rings...

    my point is .... that some particles can move easily in solution but others have characteristics that slow them down...

    i imagine that the heat cycling a steel to produce the banding is employing the easy moving elements in the alloy... ( those that can move when the carb goes into solution )

    Now.... when you completely melt steel charge..... you go that one step further....... it levels the playing field and even the big heavies that normally sit on the sidelines can now take part in the banding structure or matrix or what ever you like

    as for the hypo eutectoid... .. i just imagine that the carbon is taken out of the play... but in the crucible steel ... the heavy duty matrix is still there..... what ever that is made of..
    - as for the structure... ... Jeeeez.. i just don't know...

    it does look very nice though

    I did go over to Al's place and use his 30 ton press... with the roast i give the ingot.. alot of the cracking goes away.... ... if you look in the bladesmith cafe.... there is some photo's of it somewhere...
    -- pressing it out went by very quickly... much to quick for me ... i just couldn't believe it...
    -- yes, i do think that some wootz would be problematic on the press... pending how you make your steel..

    I think the material is so random... it's really a very unusual material


  5. #55

    Glad to hear that the press worked out for you. For me it has always been a bit iffy...but then I guess I stopped using it pretty early on in my experimentation when it gave me trouble. Might be that I'd have better success with it now. I have a 110lb air hammer as well, so I have been using that instead since I like the way it moves the material. Every once in a while I use the press to give the ingot a gentle nudge if the shape gets awkward, but I've been avoiding it for any major forging. Now I'm inclined to go back and give it another try. Despite my doubts, I think I will probably give your roasting concept a try next time as well, since it never hurts to try something that has worked for others.

    I find it very curious that you get basically the same pattern no matter which direction you forge out. It actually makes me think that this is a major insight into the pattern question. My ingots show a very fibrous pattern if I forge them out vertically, and something much closer to the traditional wootz pattern if forged out horizontally. Yours apparently look essentially the same no matter what plane you forge in. This says to me that in your ingots the dendrites form in essentially a random orientation, so that no matter which direction you look from , they are essentially the same. Mine on the other hand seem to orient pretty strongly into vertical collumns as the liquid solidifies. This is the "ingotism" that I mentioned in a couple of other posts. From what I have read of industrial steelmaking, all ingots have a layer of small, randomly oriented dendrites formed during the rapid solidification of the surface. As you go deeper into the ingot, the solidification is slower and the dendrites become larger and better organized. If cooling is too slow, only the very surface dendrites will have random orientation, while those further in become so well organized that they actually form vertical collumns. If "ingotism" is present to a great degree, the ingot will crack excessively during rolling and have to be remelted. It sounds an awful lot like I've got a case of ingotism. Now I'm going to have to go back to my books and see if there is any info on whether dendrite size and orientation is strictly a matter of cooling rate or whether some of the impurity elements can accentuate the formation of collumnar dendrites. Hmmmm...

    Does 52100 have vanadium, or is it just the chromium? I don't really use it, so I can't remember. Chromium is slightly larger than vanadium, so I assume would be slightly less mobile within the crystalline lattice. It also isn't as strong a carbide former as vanadium, not that I think that has much affect on mobility. Another steel that folks like to bring out pattern in is D-2, another steel with high carbon and high chromium. I think the difference between these two and wootz is that they have far more than just a small amount of alloying element. On top of this, the element is chromium which affects the rate of etch and "brightness' of the steel just by its presence. In these steels, once the alloys have segregated to some degree, I think that there could be no carbon whatsoever in the mix and the alloy banding would still be visible. I bet that it is possible to erase the banding short of remelting, though, if you know how hot the steel needs to be for the chromium to start diffusing and evening out. My guess is that a good cooking at 2200F or so would do the trick. This is the temperature that Verhoeven and Pendray used when reasing the wootz pattern, so it seems like a good bet. Speaking of erasing the wootz pattern, I have actually done some quick forge-welding on my blades if a small crack opened up and had no troubles with erasing the pattern. I think that it is definitely a factor of time and temperature, and as long as it isn't too hot or held there for too long, things are essentially un-affected. The fact is that some of the original wootz blades show obvious signs of forge-welding, so this shouldn't surprise me.

    In case you are curious, the blade pictured above was forged quite close to shape, and here is the wierd part, not patterned at all. This entire ingot developed what looks like a pretty regular ladder pattern through no purposefull action on my part. I forged this 8" blade plus a 20" ninja-to (don't ask me why somebody wanted a wootz ninja-to) from my last ingot, and this pattern popped up along the full length of both blades. It is more obvious in some areas than others. My best guess is that it is a result of the heavy forging I did as the ingot got forged down into bar stock. I think that it was Don Fogg who has pulled a similar trick in which he develops a pattern in PW steel by taking thick "bites" with his press, and each new shoulder that gets forged down into the bar will show up as a rung in a very subtle ladder pattern. I recall that this trick required a very high layer billet, and the pattern in wootz certainly behaves in similar ways to a very fine PW steel. Maybe this is the reason...or maybe someone else can come up with a better idea that makes more sense.

  6. #56
    Peter –
    So you think I should not be disrespecting the cementite component of pearlite, just because it doesn’t have enough carbon to stand out as a carbide on its own?

    Regarding patterns, the biggest influence on pattern I’ve noticed is degree of elongation; so if your ingots are wider than they are tall and you draw them out in the vertical direction you might get a more linear effect. It is possible to get that effect drawing out in the ‘normal’ fashion, too – the ingot this knife was made from was forged in the usual way -
    Attached Images Attached Images  

  7. #57
    Join Date
    Jan 2003
    NY State


    52100 only has chromium, no vanadium .Atomic size deosn't have much to do with things . The major point is that different metals have different degrees of bonding with carbon . V, Mo, W are the strongest ,Fe the weakest ,Cr fairly weak too. The strong bonders require higher temps and longer times to dissolve ...Industrially we do our best to eliminate segregation as dendrites and alloy banding and you wootz people want to keep it !!!
    Ascertained with certainty

  8. #58

    To my mind, a carbide is still a carbide whether it is just part of the pearlite or a particle all on its own. The free particle will be easier to see as an individual unit...but pearlite and ferrite etch very differently as well, and the only difference between them is the addition of cementite.

    My belief is that it is easier to etch for and see differences in the structure of the steel than it is to etch for and see differences in the level of the trace element which causes these structural changes. I think we would need a good metallurgist, or better yet a metallographer (I think that's what they are called) to tell us which is more visible. An example of this is that in PW steels, particularly ones with pretty simple steels, the pattern is often much more visible in the hardened section than the un-hardened...or sometimes the opposite way is true. I find that if I differentially harden a PW blade, the pattern is often quite vibrant to one side of the line, and just OK on the other. Here we see a change in structure drastically changing the etched appearance of the material without making any change in the alloys. In simple steels, it is my feeling that the structure is more visible than the most cases.

    As to the ingot forging thing, that is an interesting point...and a nice looking knife. My ingots tend to be almost exactly the same in height and diameter at the top, which very likely has an effect on the type of pattern I get. Whether the shape is affecting the pattern because of how the dendrites form during cooling or because of how the shape dictates the distortions during forging, I don't know. Maybe it is something else entirely. I do know that my ingots look quite different forged out vertically vs horizontally.

  9. #59
    Join Date
    Aug 2002
    Elliot Lake
    it really could be your cool times... .. as i usually have a small variety of melt times in a batch...
    -- the first 3 or 4 of the day get yanked out of the furnace as soon as their melted and killed... ( put in a hot box to settle and cool - kaowool lined box )
    -- my last one of the day stays in... and cools with the furnace.... ... after a little bit i put the ingots in from the previous weeks melt...for my furnace roast...... the basically just soak in the heat from the bore and stay over night..

    you are very correct... about the ladders appearing if you do some heavy fullering..... I get alot of ladders, because i do fuller all the time..... seems the more violence you do to the ingot while forging it... the more random the pattern... lol

    the ladders that you groove are abit denser ... but still the same..

    I know that hammer face has a good effect on pattern..... at one time I was trying to replicate the sham pattern... very straight sort lines... it did take awhile but what i came up with was to use a flat faced hammer... it was a 4lb french hammer that i used... and no fullering.... yes, it did take a good while to finesse the stock into a blade..... but the pattern was dead straight .....
    have you tried using a hammer with more of a crown on it... that adds alot of randomness to the pattern...
    -- i have a narrow faced 8lb hammer that i love for working this... its usually give a nice result in the end

    - do you do alot of stock reduction.... if you do... do you cut across the sheeting in wootz... that will produce alot of straight lines.... they are basically the ends of the sheets..

    its wootz.. theres nothing simple at all about the process.. haha.. if you struggle enough, occasionally you may get a nice patterned blade...
    - it is alway a surprise.. ... always

    Last edited by Greg T. Obach; 01-21-2007 at 07:38 AM. Reason: typo's... and low coffee levels in system

  10. #60
    Join Date
    Aug 2002
    Elliot Lake
    Hi Peter
    here is some pic's from my visit at Al's place and the forging press at work

    had to click on the attachments to get it to show for some reason

    and theres a pic of the wootz on Don's site

    so the press works.. .. its just a matter of coming up with a system that works for the ingot or your style of wootz

    take care

  11. #61

    It's unfortunate that the picture on Don's site doesn't show better; it looks like it must be a really nice pattern. I know that Ric Furrer also uses a press for his initial forging, but I'm pretty sure that he seals his ingots up in a box before doing it...I guess that way any cracks that develop will reweld themselves. The more I think about, the more I am convinced that the roasting is what makes your ingots so resilient. I still don't see how it could affect the pattern, but if it makes the ingot more forgeable, it is well worth the time.

    As to pattern vs forging direction, in my own ingots I have definitely found that working them vertically yields a very different pattern than working them sideways. When worked sideways, I get something that much more closely resembles the ancient patterns, although still not quite the same. Vertically I get this "stranded" pattern. My theory is that either because of the cooling rate or the shape of my crucibles/ingots, I am getting almost entirely vertical, collumnar dendrites. If I stretch these vertically, I get strands. If I stretch them horizontally, I get a slightly "broader" pattern.

    I noticed you also mentioned "killing" your ingots. Are you using aluminum wire for this? It is also implied from the statement that you are either not putting tops on the crucibles, or at least not sealing them so tightly that you can't get at the material pretty easily while it is still molton. I'll understand if this is something that you don't want to disclose...I think all knifemakers have a couple of tricks up their sleeves that they would rather not share to widely. I tried placing a small amount of aluminum in the bottom of one of my early wootz attempts, under the rest of the charge. That was the only crucible I ever had fail spectacularly...had to completely reline the furnace...I guess the crucible wasn't rated for thermite. I am currently running my crucibles without tops, but with a good layer of green glass on top instead. I haven't noticed any detrimental effects of not having it all sealed up tight...although maybe I just haven't noticed them yet.

  12. #62
    Join Date
    Aug 2002
    Elliot Lake
    Hi Peter

    yes.. I firstly started off roasting to make the ingot success rate go up.... --actually, i should start at the beginning.... at first i sectioned up some ingots into 4 bits... and tried various ways to forge out the small samples...

    - preheat the ingot... then slowly forge it out... - had real nice cracks
    - thermal cycled the ingot... still had nice cracks around the perimeter... but was able to grind a knife out of the core.... very very dendritic looking

    - electric welded a 6013 rod mild iron rim around the ingot... forged out to a blade length then ground out a knife... still very dendritic...

    - had one with a rim on it... and i could feel it going bad under the hammer... (when wootz starts to forge real easy, then its crumbling appart !) I knew this and decided to keep my temp up high... and try to re-solidify it like a canister weld... man o man, did that one turn out bad... the iron rim was left but the inside was like a cave with exploded walls.... neat but where did the wootz go?

    - tried a borax coated sample ingot.... thinking that if i keep it fluxed that i could seal up those cracks.... hahaha... i was sooo wrong.

    - eventually... i ended up roasting for short times ... like 3 or 4 hrs and having better luck..... less cracking and abit easier forging.... but still some ingots will get very cranky no matter what..... I just conclude that its in their personality..

    Killed -- I guess i have a bad habit of using this term ... i understand the process of the aluminum addition... i thought i was added at the end in very small amounts..
    - but my slang version of killed... is what i call a charge that has settled down low in the crucible...

    -- i'll describe it as i see it.. ( i know you've noticed this but others may have not noted the phenomena, so i'll go in depth about it )

    When you melt a charge... the flux/glass melts firstly, and bubbles and toils violently up and down the plates of iron and cast. It climbs up high in the crucible, almost to the point of bubbling over the top and down the crucible (occasionally it does ). If you note how high its climbing up, then you'll see later on that a difference will occur with each charge element becoming liquid.
    -- Now, the cast iron (due to its high alloy content) is next in line to become liquid. The level of bubbling will now become less violent and sit just abit lower in the crucible. Lastly, the plates of iron will dissolve as the temperature of the furnace is finally penetrated the charge. The charge will now sit much much lower.... but don't be fooled..... did all the plates dissolve ? or is there a little bit floating around .... ... alway keep a log and note these times for reference.
    -- make sure you wear good dark lenses to gaze at the charge and beware of the exhaust burning your face... ouch
    -- if you look closely... now that charge is sitting even lower... and the surface is very even and not very violent at all .... this is what i like to call a killed charge... its ingredients are clean, liquid, and not bubbly... .. this makes a very nice ingot with next to no porosity

    -- i just use a decent layer of glass for a cap... no lid unless i'm making wootz with iron and charcoal... then its necessary for the lid !! or if you feel that your fuel has some impurities in it...

    now its good to slowly dial back the furnace... not too much... just enough so that you know the charge is very slowly moving through the liquid/solid phase.... once you feel its past the liquid stage, then you can shut down and wait abit... pull the charge with some long dandy tongs... and replace with a new crucible ( thats been preheating on the furnace top all along )... wait a couple minutes till it warms up.... than start the climb up to temp with the burners..


    ps.. back home i have a whole shelf of Frankenwootzes ... lots of bad blunders on my part...

  13. #63
    Sometimes I think the Frankenwootzes are the most interesting. I think the most interesting thing that I've done while making wootz was the accidental substitution of a normal brick for the firebrick that I usually use as a plinth for the crucible. Needless to say, it didn't look good. A vitrified brick looks suprisingly like a burned marshmallow. I certainly had my share of ingots which utterly failed, mostly in the forging. I think the single most frustrating experience was having an ingot that forged out beautifully, only to discover in the grinding and etching that some of the bars of steel failed to fully melt...leaving me with a great pattern over 90% of the surface and then a few blank patches scattered just perfectly to make the whole thing useless. The most ironic part was that when I cut up and remelted the bar, it cracked during the forging the second time around.

    I guess this is what makes stuff like this so much fun...

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