The Road to Damascus Sorting Modern Pattern Welding from Myth and Legend By Kevin R. Cashen, American Bladesmith Society (ABS) certified Master Bladesmith Damascus steel, the stuff of legends. In almost every iron working culture this material was revered and bestowed with magical qualities. A crafty weathered old smith made the elements do his bidding in his dark, mysterious smithy as he performed the impossible, fusing solid, different metals to create a weapon that could slay the mightiest dragon and never fail its master. Is it the pinnacle of the metal formers art? Can we have the perfect blade with steel that is malleable and tough intertwined with super hard steel with scary cutting ability? I must start by saying that our society has used entirely incorrect terminology when labeling these materials. The layered patterned steel we are used to today would be more appropriately referred to as pattern welded or laminate steel. Many believe that the steel from the city that is its namesake was a whole different steel entirely. But since it has become an integral part of our language, I will resign myself to this incorrect terminology to avoid confusing things any farther. I did, however, feel it was necessary to make this point before continuing. In order to understand the development of pattern welding, one must look at the metal production methods of those very early days. The simplest way of obtaining iron from ore or iron oxide is by the method known as the direct process. Iron ore was placed in a large primitive furnace with liberal amounts of charcoal fuel, which was burned to produce the tremendous heat required. But, more importantly, it also produced carbon monoxide. The carbon monoxide passed through the super heated iron oxide stripping away oxygen as it went. Carbon dioxide was formed with the extra oxygen; thus leaving purer iron particulates that drizzled down to the bottom of the furnace to form a dirty, porous iron "sponge" called a bloom. This bloom was removed and hammered while hot to squeeze out the silicates and other contaminates and to close the voids. This produced very small amounts of iron in comparison to more modern means and the metal was fairly crude due to the fact that it never totally achieved a true molten state. With this, or naturally occurring bits such as meteoric or bog iron, being the only source, iron was a scant commodity. These small chunks of iron would then be packed into a closed vessel with a heavy carbon bearing material and heated to a high temperature for many hours or even days. The time at temperature allowed the iron to absorb the carbon via carbon migration (the tendency for carbon to be absorbed into iron until a sort of equilibrium is achieved will be back to haunt us many times in this discussion), a process we now know as Cementation. When the pieces emerge from this treatment they are steel, an alloy of carbon and iron. When several small chunks of steel were achieved they could then be heated in a forge and welded together to form larger pieces. It is almost inevitable that in the process of welding one will fold the steel back upon itself to build up the mass as the work piece lengthens and becomes thinner. The subsequent hammering and welding also refines and purifies the steel further as well as evenly distributing carbon. This crude steel was improved by hammering! It was also made even better by folding! A legend was born. The smiths of medieval Japan developed a method of metal refinement that was unique to them and very effective. Using an iron rich sand, the same basic methods used in the direct process were utilized but the bloom was allowed to cool so that it could be removed from the spent furnace and examined. Select pieces of steel were broken from a bloom which ranged from very mild steel to cast iron. The selected parts were then welded together and folded upon themselves repetitively to refine the metal known as Tamahagane. Early welded blades by Celtic tribes were straight rods welded together with the seams running lengthwise along a blade of lower carbon content steel. Writings indicate how unimpressed the Romans were with these blades, as they bent easily in battle and split out as the welds failed. But during the time known as the Migrationary period (400-800 A.D.) true pattern welding appeared. If the rods that created the long lengthwise seams in the blade were twisted together, the problem of welds coming apart was greatly reduced. The great amount of oxide scale produced by forging would break free and fall off during the twist, resulting in better welds. Twisting is also a great test of how sound the welds are. If the welds were not good, the stress of twisting would let you know immediately. So, the twisted pattern could actually have been a mark of quality very early on. There could have been many other practical reasons for twisting in the beginning, but soon the development of intricate patterns in the blade became an art form unto itself. Analysis of the steel in such blades shows some bands of steel with a relatively high phosphorus content. The higher phosphorus would cause the steel to etch out lighter than the purer steel. When one gets a rare glimpse at one of these original swords you are moved by how gorgeous the pattern still is in a thousand year old blade that is mostly rust. That these weapons were fit for kings is echoed in the fact that even after they were abandoned for homogenous steel, some swords still bore an inserted panel of simulated pattern welding. I almost have to refrain myself from anger when I hear the smiths of northern and central Europe, in the dark ages, stereotyped as uncivilized barbarians. Examples of Saxon and Viking blades with multiple bar cores of intricate patterning with fine steel edges welded continuously around the outside speak loudly of metal working skills unparalleled in their time. Many other cultures made laminated steels but none developed patterns with the same class as these folks. Trust me when I say that it is not the easiest thing to do even today with the absolute best tools available! Other cultures were also able to go beyond the subtle all silver-gray damascus by the use of different alloys, centuries before there was any real scientific understanding of it. More than one culture in utilizing float iron stumbled upon the high contrasting strange iron that fell from the sky. Meteorite was sought after ages ago for the beautiful effect its high nickel content had upon the steel. Good examples of vibrant patterned Kris blades from southeast Asia can be found that purposefully had high nickel meteoric iron, producing a bold, black and silver contrast. Many believe that the material that was the original Damascus steel was a product of India known as wootz. The town of Damascus was never a great producer of steel but rather the hub of the great trading network in the Middle East at the time; thus most blades of this steel came to the west from Damascus. Interestingly enough, wootz is not a product of folding and welding two different metals at all, but some of the world's first examples of homogenous high carbon steel. One of the qualities of steel that the Indians took advantage of was the fact that the more carbon steel has, the lower its melting point. Other cultures were hindered by the heat limitations for melting iron. To get iron to a complete liquidus requires much more heat than the direct process can produce. The Indians packed the raw iron into tightly sealed crucibles with carbon bearing material and then heated them for some time in large fires. As the iron absorbed the carbon in its sealed environment, it would lower its melting temperature. The lower the melting temperature the more carbon was absorbed until a vicious circle was formed within the crucible, resulting in a fairly clean, cast, high carbon steel. Folding and welding to build up mass and cementization was not necessary. The pattern in wootz is caused by the large amounts of carbon (cementite) in the steel. Tamahagane, pattern welding, and wootz were the best steels ever produced in their time but we have a tendency to think that they were abandoned because we got lazy or wished to sacrifice quality for quantity, as armies grew larger. But the fact is that mankind spares no expense in war and would not abandon quality weaponry for something that wouldn't give an advantage in battle. As foundry technology improved, the blooms coming from the furnaces grew in size until it just wasn’t necessary to weld rods together any more. Wootz held on as a quality product for some time, but even the true damascus steel eventually became obsolete in the face of better efficiency. The Catalan furnace eliminated the need to tack scarce quantities of steel together. And, with the advent of the Bessemer process, man had the ability to produce any quantity of steel he wished. In its day, damascus steel in its various forms was far superior to iron, as was an abacus to counting upon ones fingers and toes. Today, however, nobody doubts the superiority of a 400mhz PC to the antiquated abacus for crunching numbers. For some reason, steel is different in our minds. The fact is that today we produce huge quantities of the finest materials ever made for purity, consistency, strength, and so on. Our understanding of alloys and metallurgy allows us to create steels that make many of the ancient ones look like the slag from our furnaces. Few today, however, would have the skill or the patience to produce such a weapon with those tools and materials. So these points are by no means a criticism of the blades of the past, just a reality check. DaVinci used some pretty lousy mixtures in his paints compared to what is available today (many paintings are virtually self-destructing), yet I don't believe there is anybody alive today that can match a DaVinci. Leonardo was the master and his work has an unsurpassable immortality despite how superior our modern materials may be. The same is true of the bladesmiths of the past. How is this stuff made anyhow? Many of the original methods are buried so far back in history there is no way to describe the specific techniques. But it would suffice to say that any body who plays with hot iron in a heat as clean as a pure charcoal fire will inevitably stumble upon forge welding. I can share with you my methods, which seem to work well for myself other smiths. Starting with five layers of two different alloys (e.g., three layers O1 and two layers L6), I stack them, alternating, in a bundle. A handle is welded on for easier handling and the heating begins. When the stack starts to glow bright red, I apply a flux in the form of powdered borax. The flux liquefies at this high temperature and coats the steel, preventing oxidation that would put an end to any hopes of welding. In its liquid state the flux also acts as a medium into which iron oxide and other contaminants can dissolve and be carried out upon welding. The steel is placed back in the fire and heated to welding temperature. Many blacksmiths used to working with wrought iron believe that welding temperature is when the steel sparks. For carbon steels this is "burning" temperature and you will ruin it. At the right temperature the flux will flow very evenly over the orange glowing billet and a few bubbles will "skitter" on the surface. It is hard to describe the proper time, as it is a sense that is developed from experience. At the right temperature the billet is quickly removed from the fire and lightly hammered solid. Liken this to heating two pieces of wax until they are very soft and then pushing them together. Unlike modern welding, there are no puddles or beads of liquid metal, so the layers maintain their separate qualities (with the exception of carbon content). When the layers are forced together, the flux between them is ejected in a molten sheet of sparks, making things real interesting in the shop. If all went well, there is now a solid bar consisting of five layers. This is then hammered out to twice its original length and then cut 3/4 of the way through, in the middle, to allow folding. Before the fold, I use a hand held grinder to quickly grind the surfaces clean of scale and decarburised iron. It is then fluxed, folded, and welded again. This process is repeated until the desired number of layers is achieved. With the revived popularity of this material in recent years has come abundance. Just about every person forging blades eventually gets around to making some damascus. Unfortunately, good stuff and good makers are few and far between. The major contributor to this problem is misinformation. Here is where all the mythology and folklore has hurt the most. At the top of the list is the many legends of the superior nature of the material, which I hope I have thoroughly covered by now, but there are many other myths surrounding this mysterious metal such as the following: Myth #1 If there is one bit of information that seems impossible to dispel it is the concept of a super steel for blades being created by layers of high carbon (hard) and low carbon (soft). The idea being hard layers giving the edge holding, cutting ability, and the soft layers holding everything together by bending or flexing instead of breaking. This is a myth! Unfortunately it just isn't that simple, and every time a smith mixes mild steel into his damascus, and gets a tougher blade from it, the myth is perpetuated. What has actually occurred in this situation is carbon migration from the high carbon steel to the low carbon steel until all layers are of medium or lower carbon content. It makes a very tough blade, but much of its edge holding ability has been sacrificed. A fellow bladesmith drummed the easy formula even into my thick skull before publishing it in a popular knife magazine. The mathematics is simple. If you start with two layers of .8 % carbon (high carbon) and three layers of .18% carbon (low carbon), fold as much as you want, and the billet still started out at 40% high carbon and 60% low carbon. Multiply 40% by .8% and 60% by .18% and add the two together and you get a lackluster total of .44 % carbon. This carbon percentage would be barely hardenable, and with time at welding heat you would lose even more. Many smiths who add low carbon steel in the mix complain that they have to use extreme quenches like water or brine to get any noticeable hardness. One should take a hint from this. In testing these concepts, I have broken literally buckets full of laminated material, and not once has a high carbon/low carbon mix resulted in a break that would characterize this holy grail. No clean breaking hard layers sandwiched between stretched and bent malleable layers. To achieve this, one needs a metal that carbon does not like. In recent years this was found. With care, pure nickel can be welded to high carbon steel. The contrast is beautiful, but no matter how you heat-treat it, nickel cannot form martensite (the hard form of steel). Higher nickel content steel can also retard the process. So here we have it, very hard layers between tough softer stuff, but I have heard plenty of complaints from people who have used such blades and found their edge holding ability lacking. It seems that when this long sought after material was finally achieved, it was not a real great cutter. Solution--use only good hard steel at the very edge and keep the soft stuff in the spine and body of the blade. A good rule of thumb for damascus is never put anything at the cutting edge that wouldn't make a good knife all by itself. Myth #2 Despite popular belief the art of damascus making was not a lost secret that was only recently rediscovered. It does however make the story that it is an ancient, secret, super-steel more believable and interesting. Fine examples of pattern welding exist from earlier in this century and the last. Examples made in France in the last century have legible words and sentences welded into the layers. The basic process is actually a simple technique that any blacksmith accomplished in forge welding can perform. The aforementioned kris blades have been skillfully made in primitive jungle forges with simple tools from ancient times right up to the present. It would seem that only a hand full of westerners forgot how to make the stuff. Myth #3 More a misunderstanding than myth is the concept of layers being equal to folds. A 320 layer damascus blade could have only been folded six times. It is a simple matter of geometric progression. If you start with 5 layers of steel, folding it once will give you 10 layers, fold 2 makes 20, fold 3 makes 40, fold 4 makes 80, fold 5 makes 160 and six equals 320 layers. So a katana with 32,768 layers could have started with only two layers and would only have to be folded fourteen times! Those ancient smiths weren't quite as ambitious as we thought, or at least a little more human. Myth #4 The more layers the better. Back when steel needed refining, by welding and hammering, folding did help but there was a point after which you were just wasting time and steel. Today if you are using an all high-carbon or tool steel mix, the layers are purely a matter of aesthetics. With such a combination, two is as good as two hundred, with the two hundred offering more opportunities for things to go wrong. With a high/low carbon mix one wants to weld enough to allow carbon migration to help equalize the mix. This occurs much quicker than you would think. Under certain conditions just a few folds could do the trick. Most smiths don't realize that carbon migration is actually their friend, saving them from the embarrassment of a blade that has soft spots on the edge. When shopping for modern damascus steel blades, like in anything else - "Caveat Emptor!" The chances of getting an inferior blade are greater with damascus steel than a homogenous blade. Why is this? The problem with making damascus is the complexity of the procedure, the more complex it is the more things can go wrong. The temperatures involved in forge welding open the doors for uncountable problems. Over heat it and you ruin the steel, under heat it and the welds may not be sound. Carbon loss and contamination between the layers are a constant threat to the final product. This is assuming that a proper mixture of steels was used to begin with. But, in choosing steels, compromises in desired qualities may have to be made. For instance, is it pretty enough for you? One can make some great cutting mixtures that are gray and gray to look at. But you can also get a real beauty to behold that holds an edge like soft lead! Are the two alloys compatible? This is one that is greatly ignored by many. One steel is tricky enough to work and heat-treat, but two make things twice as difficult. Every steel has its own narrow temperature range to achieve a proper heat treat. With dissimilar steels, the window gets narrower in which you can successfully heat-treat both steels. When the windows don't line up, you must choose between the lesser of two evils. You may not get one steel fully hard or shock and stress the other beyond all reason. If you go with the former, you could get distortion as the steel expands when it forms martensite and the one that didn't go through this transformation would get tugged around a bit. Then the finished blade may not hold up at the edge as well as expected. If you take the latter approach, the blade will be hard but full of all kinds of stress, and possibly even very fine layer cracking that will go completely unnoticed until the blade fails one day. As you can see things can get very complicated when more than one steel is involved. Before buying, get a feel of how the maker views his damascus. I always advise that if given two smiths, one who extols the virtue of his damascus and treats it like it was gold and the other who feels it is just another steel and trips over more of it, on his dusty shop floor, then he sells. Always go with the second guy. The first probably hasn't made enough of it for the novelty magic to have worn off and would have a harder time scrapping a flawed piece. Whereas the second guy has the stuff coming out his ears and will have no problem letting a less than perfect piece join the others in the dust. Ask what goes into it. Old files, truck springs, and other scrap steel do make interesting blades with a history, but they are not reliable. You will probably be paying a good amount, if it is damascus, so you deserve the best materials the smith can get. Good, new, identifiable steel is not that expensive and if the maker is too cheap to spring for it then you can't "afford" his scrap steel blades. Though many would disagree with me, and it is just my opinion, but I would also suggest not buying steel that has been watered down with anything that doesn't harden by itself unless the final carbon percentages work out. And most important, avoid those who make extraordinary claims based on the mythology and hype. The truth about damascus is that, if the smith creating it is really good, it can be every bit as good as the individual metals that went into it, but no more. It could very easily be a waste of two perfectly good steels if the smith isn't really on top of things. One could hope that by mixing shock resistant steel with a great edge holder, one can get a blend of the two. The old legend of improving steel by folding and hammering was once a fact, but is quite obsolete now. The real virtue of this material is its enchanting beauty. Of all the materials I have worked, or even seen, none have the naturally mesmerizing effect as damascus steel. The same unexplainable pull that forces one to stare at a campfire at night is present in the lines and swirls of damascus. And when one gazes upon it, they look back across the centuries to when a smith put his heart and soul into his creation and the warrior had an intimate bond with his trusted blade. With one of mankind's oldest crafts, the smith uses the ancient basic elements to create some of the most beautiful material made by man. This stuff has a most noble history with a look and feel that is timeless and ancient. And that is the true magic of damascus! Kevin R. Cashen is certified by the American Bladesmith Society as a Master Bladesmith. A winner of various awards including "Best Custom Straight Knife" (for a short sword!), Kevin is well known for his high performance art swords rarging from rapiers to Viking swords. He is also the maker of this month's cover sword (click thumbnail to expand), which is a Viking sword sporting pattern-welded steel and Celtic gold designs. Kevin resides in Hubbardston, Michigan. mailto:krcashen@mvcc.com BACK [TOP]