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The Riddle of Steel


“...And the secret of steel has always carried with it a mystery. You must learn its riddle, Conan. You must learn its discipline...”
- Conan the Barbarian





Contents:

  • The Making of Steel
  • Purchasing a Medieval Sword Replica
  • The Care and Feeding of Swords
  • Collecting Historical Swords
  • A Little About the History of Swords
  • Credits






  • Do you want to purchase a sword or hand weapon but don’t know anything about steel? Have you ever dropped a steel sword and bent the blade?! Has your favorite sword suddenly begun to rust? Have you ever wondered whether the secret of steel really WAS left laying on the battlefield by forgetful gods? Well, I have! The following is the fruitful end of a long journey I undertook to find the answers to these questions...



    The Making of Steel

    For many, many centuries only a few master smiths knew the secret of how to make a sword of steel. And before that, steel and iron were once thought to be magical substances. There is evidence suggesting that the iron found in early artifacts was not man-made but was taken from the fragments of meteorites. In many primitive or prehistoric cultures, the word “iron” actually means “stone (or hard substance or metal) from heaven”, “star metal”, or some other meaning suggesting an other-worldly origin. Chemical analysis of the earliest iron artifacts show the same percentages of nickel that is found in meteoric iron. During the last century, some “primitive” cultures have even been observed using iron from crashed meteorites to make various useful tools. Did Robert E. Howard, the creator of Conan the Barbarian, know this when he defined magical swords as being forged from the other-worldly metal of meteorites?

    Steel is made by taking iron and combining it with a small amount of carbon. Iron isn’t just found lying on the side of the road, though (with the rare exception of meteorites). Iron actually comes from a black rock known as iron ore, which is usually mined deep underground. In order to get the iron out of the ore, the rocks have to be heated to extremely high temperatures using a process called smelting.

    One of the tricks to smelting iron ore and forging steel was to get the fire to burn hot enough to produce the metal. The best way to get an open fire to burn hotter was to introduce more air and oxygen into the fire. Thus, many forges and smithies were built on the sides of hills where strong winds would fuel the fires of their forges. In the 4th century, the bellows was invented to pump air into the forge fires manually. Some “steel historians” say that smelting was discovered by accident and only because of a strong wind blowing on some lonely hill or mountain peak campfire!

    Not all of the iron produced from primitive smelting was useful, however. Some was dirty, brittle cast iron which was so hard and brittle it could not be shaped and worked, but a few lumps from every smelting were probably free enough from carbon to be malleable. In the traditional medieval method, the iron ore was smelted in an open forge and resulted in a substance called bloom or sponge iron. This material was a soft, spongy mass of reduced iron and slags (impurities) left over from the smelting process and was completely useless in its original form. During the medieval period in Europe, forges did not have the ability to burn hot enough to melt iron to a molten or liquid state, and thus were forced to work with bloom iron. In order to refine the bloom iron into a usable form, the iron needed to be repeatedly re-heated at welding temperature, between 2200 and 2700 degrees F depending of the carbon content, and repeatedly hammered or worked. This welding/forging/welding process reduced or “burned off” the excess carbon in the atmosphere of the forge and essentially “forced out” the other impurities through hammering, bending, and pressing. This made the metal free enough of impurities to make it workable.

    The iron that was nearly pure, with less than .3% of carbon, was called wrought iron. This type of iron was excellent to work with, weld, and shape, and was able to be hardened by hammering. Wrought iron’s molecular structure was made up of fibers formed from the absorption of silica into the iron during smelting. When hammered, the fibers of the cold wrought iron were pressed and packed tightly together, making the iron harder, stiffer, and slightly more brittle. Hammering wrought iron was a delicate process for even a master craftsman. One blow too many, and the fibers in the metal would separate instead of pack together, forcing the blacksmith to re-heat the metal and return it to its original form. Another difficulty for the blacksmith was that wrought iron was susceptible to “red short”, where the iron simply crumbles if heated too hotly. Shaping and hardening iron without heating the metal is called cold forging.

    Wrought iron is rarely used now except in unusual cases where durability and other particular characteristics are desired. For the most part, mild steel is now used where wrought iron was used in the past, and has many of its characteristics, including softness. Mild steel is softer, however, and bends easier than wrought iron. This is because mild steel doesn’t have silicate fibers contained in its molecular structure. Because of this lack of fibers, mild steel can be bent at acute and steep angles without weakening, unlike wrought iron. However, mild steel also rusts and corrodes faster than wrought iron due to its lack of silicates, thus making it less durable.

    The problem with wrought iron is that it bends pretty easily. Even if cold hardened, a wrought iron sword quickly loses its cutting edge and, if used enough, would eventually become nothing more than a big iron club. However, wrought iron can be formed into an even harder substance by adding carbon to the metal, or carbonizing. The carbon gets into the iron from exposure to charcoal that is on the bottom of the fire used when heating the metal. Charcoal, charred remains of bone, burnt leather, or nearly any charred organic substance is essentially carbon. One of the most plentiful sources of carbon is coal, which is baked at high temperatures in a oven to produce coke. I’ve always thought that coke was really CHAR-ed COAL. :-) Once the carbon and iron are combined, this harder metal that is produced is called steel. In its simplest form, steel is an alloy of pure iron with less than 2% carbon. This steel can then be hammered or reshaped into a sword, axe, or whatever before it cools.

    Both the cementation and crucible processes were the primary ways of making steel throughout the ages until modern times. The cementation process was used to produce steel by taking wrought iron and tightly surrounding it with carbon powder, then heating both, without any contact with air, so that the iron absorbed more carbon. This was the process used to case harden a sword. The iron would absorb the carbon only on its outer surfaces, thus “encasing” the iron blade in steel. The longer that the blade was left in the surrounding carbon, and the hotter the forge fires, the more carbon would be absorbed and the deeper into the blade it would penetrate.

    In general, the more carbon that iron absorbed (up to 4 %) the harder it became. The degree of carbon that an iron metal contains is measured by a point system corresponding to the hundredths of a percent of carbon contained in iron. For example: a steel containing 1% of carbon has 100 points of carbon; steel with 0.45% carbon has 45 points, and so on.

    The crucible process produced steel by melting wrought iron in clay “crucibles” containing a precise amount of carbon to mix with the iron. Because the iron was encased in a clay jar, it did not make contact with additional carbon, soot, slag, dirt, and other impurities from the fire. This process also produced a higher grade of steel than the cementation process, and created a steel that was homogeneous throughout, meaning, the carbon was equally distributed throughout the piece of iron. This was important because if the carbon was not equally distributed, part of the steel would be stronger than other parts, and thus prone to break. The crucible process produced such high quality steel, that it was used until the modern electric arc and basic oxygen furnace processes were invented during this century.

    Modern steel makers no longer have to work with a solid mass of sponge or bloom iron, or deal with case hardening. Instead, all iron is smelted to a pure liquid state through chemical and heat treatment, and then specific quantities of carbon are added to molten iron to produce the desired characteristics. The steel is then taken by the blacksmith and either re-melted or heat treated in order to forge it into the shape desired. If there is too much carbon in the steel for the blacksmith's purposes, the steel can be heated to a fairly high temperature in order to burn off the excess carbon.

    One of the most important properties of iron alloyed with carbon is its ability to become even harder than its carbon content alone allowed. This was done by rapidly cooling, or quenching, the hot metal in water, brine, or oil quickly after heating. When the steel is heated to its critical temperature, determined by the amount of carbon in the metal, the carbon atoms move from the outside to the center of the iron’s crystalline molecular structures which have expanded due to heating. Quickly cooling the steel freezes, traps and packs the carbon atoms inside the shrunken iron crystals, thereby producing a very hard and brittle metal. This is called hardened steel.



















    The problem with hardened steel is that it lacks toughness and is very brittle, meaning that although the metal is very hard, it cannot absorb much shock or impact without breaking. When steel breaks, it can fling sharp shards of metal in various directions and can be very dangerous! Fortunately, hardened steel can be reheated to a relatively low temperature quickly after quenching to make it less brittle, without drastically reducing the hardness obtained from quenching. This softening process is called tempering. The process of removing all the hardness in steel is called annealing. In general, the higher the heat, the softer the steel will become during the tempering process. Blacksmiths of old have always held, “It is better to bend than to break.”

    The word “tempering” is often mis-used to mean quenching or hardening due to an ambiguity of the word that means “to harden steel by reheating and cooling in oil,” which is a specific type of quenching that usually takes place after the metal is first quenched in water a few times. The word “temper” also means the degree of hardness or resiliency given steel after tempering; the color of steel after tempering; and the carbon content of steel as it relates to hardness. Not to mention having “temper” tantrums! No wonder people are confused!

    Sometimes, after hardening and tempering, a piece of steel doesn’t become as hard or tough as the blacksmith desires. In order to recycle the piece of steel and start over from scratch, the piece of hardened steel needs to be normalized. Normalizing is the process of removing all the stresses in hardened steel, thereby returning its crystalline molecular structure to the original condition that existed before quenching. This is done by heating the steel to approximately 1600 degrees F, and then cooling slowly in a dry medium such as sand or ashes. Normalizing is also used to refine the steel’s structure for further heat treatment.

    The three processes of quenching (hardening), tempering or annealing (softening), and normalizing (restoring) steels are also generally referred to as heat treating. Steel can be reheated several times in order to perfect the desired characteristics of the metal. A “heat” refers to each time a piece of iron is heated. For example: if a piece of steel has had 3 heats, it has been reheated 3 times. However, if the heat is too hot, the metal can “burn” and lose not only its properties acquired through heat treating, but large portions of the steel can be burnt away in the atmosphere of the forge fires, losing carbon, iron and other desirable elements.

    Steel can also be combined with other elements (or alloys) in order to produce particular properties, such as greater strength, resiliency, durability, a nice color, etc. There are about 20 different elements which can be alloyed with steel. If you are interested, these elements are: manganese, silicon, nickel, chromium, molybdenum, vanadium, aluminum, tungsten, niobium, nitrogen, sulfur, copper, boron, lead, tellurium, zirconium, titanium, cobalt, selenium, and of course, carbon. Stainless steel is an example of an alloyed steel, and consists of 16 to 26% chromium and up to 35% nickel.

    It is worthwhile to mention cast iron, also sometimes referred to as hardened iron. Early cast iron was made by smelting the iron longer to absorb more carbon from the coals (about 2 to 4% total). This produced a metal that had a lower melting point. The iron here was heated to such a point as to make it molten. Then it could be poured into molds and “cast” into useful items, such as cauldrons. Even though cast iron is extremely hard and has a lower melting point, it is brittle and unmalleable, i.e., it can not be reshaped by hammering or rolling but only by re-melting. On the other hand, the exceptionally skilled blacksmith Dr. JP Hrisoulas, stated that he has actually forged and reshaped cast iron without melting, but it takes exceptional skill and is thus exceptionally rare.

    Trying to figure out EXACTLY what kind of steel to purchase can be extremely difficult. There are several thousand grades of steel, all of which have different chemical compositions. Special numbering systems have been developed in several countries to classify the huge number of alloyed steels. In addition, all the different possible heat treatments, microstructures, cold-forming conditions, shapes and surface finishes mean that there are an enormous number of options available to the steel user. However, they can be classified into three classes (for what it’s worth):


    Carbon steels - most common type- contain between .015 to 2% carbon
    Low-alloy steels - contain up to 8% alloy
    High-alloy steels - contain greater than 8% alloy- prized for unusual properties


    Another classification group relates to the carbon content of the iron. According to the American Iron and Steel Institute (AISI) and the Society of Automotive Engineers (SAE) the carbon point scale is as follows:

    Mild-carbon steels - 1 to 20 points of carbon - can not be hardened
    Low-carbon steels - 20 to 45 points of carbon - affected little by hardening
    Medium-carbon steels - 46 to 60 points of carbon - tough and durable
    High-carbon steels - 65 to 100 points of carbon - hard and “springy”
    Tool steels - 100 to 150 points of carbon - very hard and brittle


    To summarize, steel is made by following these steps:1) Smelt iron ore to extract iron metal or wrought iron
    2) Hammer, pound , forge, or pour the metal into the desired shape
    3) Carbonize, or alloy the iron with carbon by heating both to encase with steel
    (hammer again)
    4) Quench, or cool, the hot steel quickly to harden
    5) Temper the steel by reheating at a lower temperature to make less brittle


    The particular step to step instructions for forging steel and the instruments used vary greatly from process to process, country to country, and from age to age. Unfortunately, this is way too much information to put here!

    However, for those of you whose curiosity about steel and swordmaking is now peaked, I highly recommend Dr. Jim P. Hrisoulas' three books, "The Complete Bladesmith: Forging Your Way to Perfection," "The Master Bladesmith: Advanced Studies in Steel," and "The Pattern-welded Blade: Artistry in Iron." These are great books, stocked full of infomation! The books are written in a very candid and useful manner, earnestly exposing the "mysteries" of steel and the art of sword making. Dr. Hrisoulas' attitude can be summed up in a quote found in the preface of one of his books, "There is no deed greater than the passing of knowledge from one to another, for without it, we would all be lost in ignorance." A sentiment of which I wholeheartedly agree!




    Purchasing a Medieval Sword Replica

    A real Medieval sword was made from wrought iron not steel. The sword smith would take the blade and case harden the edges with carbon, thus encasing the blade with steel. This provided the strength in the cutting edge. He would then temper the blade to give it flexibility.

    An interesting piece of trivia, case hardened swords were only sharpened or beveled on one edge. This was because the sharpness of the edge was held or maintained by the steel which was only on the outer surface of the blade.

    Many swords are made where the steel is very soft. The reason is this: they keep their costs down by not tempering the blades, because most swords end up as wall decorations and are not intended for any other use. They are great for that purpose. However, the difference in cost between a good quality steel and a mild steel is between a few cents and a few dollars. One wonders why so called “sword companies” would purchase such substandard steel. It doesn’t take very long to properly heat treat and finish a quality piece of steel!

    If you want a good sword that you can knock around with, take to events, stick in the ground and lean on etc., then your best bet would be to get any sword that has a spring steel or high carbon blade. The temper of spring steel has between 70 and 80 points of carbon. These blades have more or less the same properties as their Medieval counterparts, and it is unlikely that a high carbon spring steel sword will bend or dent.

    One common way to tell a strong hard steel sword from a mild steel, stainless steel, or wrought iron sword is by its glean. Generally, heat tempered blades are far less shiny, indicating greater strength. However, any steel can be highly polished and finished so be careful. This might not necessarily indicate a good steel, but only a good shine.

    “Mild steel” is something to look out for if you are interested in a solid sword. It is a soft metal and unless you want to treat it as if it were made of glass, I would recommend that you avoid it . Although, if all it does is hang on a wall, I suppose it’s O.K. If dropped, a mild steel blade will bend!

    Stainless steel is also a metal to be avoided in swords. Stainless steel is usually made of a low grade alloy that is either too soft or too brittle to hold up under any kind of stress.

    I understand that the best kind of sword one can purchase is a hand made sword forged by a skilled SWORDSMITH. The difference between a factory made sword and a hand-forged sword is that a swordsmith can vary and grade the temper (the amount of carbon) so that the edge is hard and holds it sharpness, while the middle or spine of the sword has a softer, break-resisting temper. The factory sword maker must compromise by heat treating to an average temper throughout the entire blade, thus making the edge duller and the blade more brittle. A swordsmith is a different kind of craftsman than the blacksmith. Usually, a blacksmith simply does not have the understanding of proportions, heat treatment, cross sections, etc. that must be understood in order to make a decent sword. Seek out a swordsmith whenever possible. Unfortunately, I also understand that there is usually a very long waiting list for handmade swords.




    The Care and Feeding of Swords

    Touching a steel or iron blade with bare fingers can cause it to rust. This is aptly called “poisoned fingers” and is due to the various acids excreted in sweat. The only way to stop poisoned fingers is to immediately wipe the blade with an oiled cloth. Gun oil is good. This removes the finger marks and prevents rusting.

    I highly recommend keeping the sword dry, and do NOT store the sword in any kind of sheath. Moisture can condense inside the sheath and cause the blade to rust.




    Collecting Historical Swords

    Determining a sword’s country of origin can be a confusing matter when looking to purchase a collector’s sword. Over the centuries, the leading sword-makers were from either Cologne of Germany, Poitou of France, Passau, Pavia of Italy, Valencia of Spain, Solingen of Germany, and Bordeaux of France, while blades from Toledo of Spain and Toloseta were reckoned to be the finest in the world. Some say that a mysterious chemical property found in the gushing waters of the River Targus, which surrounds Toledo on three sides, enhanced the forging and tempering process to such a point as to endow those blades with a near magical hardness and with a cutting edge rivaling the blades of ancient Japan.



    A Little About the History of Swords

    The sword, as opposed to the dagger, first began to appear in the Bronze Age (about 3000 BC). These swords were usually made of copper or bronze and had long, leaf-shaped blades, and with hilts that were simply an extension of the blade in handle form. Crude steel swords were first used in ancient Egypt (around 900 BC). Quenching and tempering steel was also known as early as 900 BC, also by the Egyptians.

    The typical sword consists of a long blade, a hilt (or handle), and usually a guard (or cross-bar). The guard was used to stop an opponent’s weapon from sliding down the blade and wounding the sword arm or hand, and also used as a tool for dis-arming an opponent in certain styles of sword combat.

    With the advent of repeating weapons, the use of the sword as a military weapon declined sharply. In the eighteenth century the use of the sword was revived a bit as a means to fight a duel, but then died out again. Now, swords are relegated to the collector, certain formal ceremonies, and the odd simulation or hobby. A group in the United States called The Society for Creative Anachronism keeps alive the art of ancient hand to hand combat though various tournaments and events.



    Credits

    Many thanks to the following sources that helped me write this document:

    BOOKS:
    The Collector’s Guide to Militaria - by Derek E. Johnson
    The Making, Shaping, and Treating of Steel - edited by Harold E. McGannon (U.S. Steel)
    The Art of Blacksmithing - by Alex W. Bealer
    Edge of the Anvil - by Jack Andrews
    The New Encyclopaedia Britannica, 1992 ed.

    COMPANIES:
    By The Sword
    The Blade Shoppe

    PERSONS:
    Dr. JP Hrisoulas
    William Thomas Powers
    ...and myself

    SUGGESTED READING:
    The Complete Bladesmith: Forging Your Way to Perfection - by Jim Hrisoulas
    The New Anvil's Edge - by Jack Andrews
    Master Bladesmith: Advanced Studies in Steel - by Jim Hrisoulas
    The Complete Modern Blacksmith - by Alexander G. Weygers







     
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