Damascus steel is the forged steel of the blades of swords smithed in the Near East from ingots of carbon steel imported from Southern India or made in production centers in Sri Lanka or Khorasan, Iran. These swords are characterized by distinctive patterns of banding and mottling reminiscent of flowing water, sometimes in a "ladder" or "rose" pattern. Such blades were reputed to be tough, resistant to shattering, and capable of being honed to a sharp, resilient edge.
A Japanese sword is one of several types of traditionally made swords from Japan. Bronze swords were made as early as the Yayoi period, though most people generally refer to the curved blades made from the Heian period (794–1185) to the present day when speaking of "Japanese swords". There are many types of Japanese swords that differ by size, shape, field of application and method of manufacture. Some of the more commonly known types of Japanese swords are the uchigatana, tachi, ōdachi, wakizashi, and tantō.
Pattern welding is the practice in sword and knife making of forming a blade of several metal pieces of differing composition that are forge-welded together and twisted and manipulated to form a pattern. Often mistakenly called Damascus steel, blades forged in this manner often display bands of slightly different patterning along their entire length. These bands can be highlighted for cosmetic purposes by proper polishing or acid etching. Pattern welding was an outgrowth of laminated or piled steel, a similar technique used to combine steels of different carbon contents, providing a desired mix of hardness and toughness. Although modern steelmaking processes negate the need to blend different steels, pattern welded steel is still used by custom knifemakers for the cosmetic effects it produces.
Steel is an alloy of iron and carbon with improved strength and fracture resistance compared to other forms of iron. Because of its high tensile strength and low cost, steel is one of the most commonly manufactured materials in the world. Steel is used in buildings, as concrete reinforcing rods, in bridges, infrastructure, tools, ships, trains, cars, bicycles, machines, electrical appliances, furniture, and weapons.
A blacksmith is a metalsmith who creates objects primarily from wrought iron or steel, but sometimes from other metals, by forging the metal, using tools to hammer, bend, and cut. Blacksmiths produce objects such as gates, grilles, railings, light fixtures, furniture, sculpture, tools, agricultural implements, decorative and religious items, cooking utensils, and weapons. There was an historical distinction between the heavy work of the blacksmith and the more delicate operation of a whitesmith, who usually worked in gold, silver, pewter, or the finishing steps of fine steel. The place where a blacksmith works is called variously a smithy, a forge or a blacksmith's shop.
Differential heat treatment is a technique used during heat treating of steel to harden or soften certain areas of an object, creating a difference in hardness between these areas. There are many techniques for creating a difference in properties, but most can be defined as either differential hardening or differential tempering. These were common heat treatment techniques used historically in Europe and Asia, with possibly the most widely known example being from Japanese swordsmithing. Some modern varieties were developed in the twentieth century as metallurgical knowledge and technology rapidly increased.
Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer or a die. Forging is often classified according to the temperature at which it is performed: cold forging, warm forging, or hot forging. For the latter two, the metal is heated, usually in a forge. Forged parts can range in weight from less than a kilogram to hundreds of metric tons. Forging has been done by smiths for millennia; the traditional products were kitchenware, hardware, hand tools, edged weapons, cymbals, and jewellery.
Heat treating is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve the desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching. Although the term heat treatment applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding.
Forge welding (FOW), also called fire welding, is a solid-state welding process that joins two pieces of metal by heating them to a high temperature and then hammering them together. It may also consist of heating and forcing the metals together with presses or other means, creating enough pressure to cause plastic deformation at the weld surfaces. The process, although challenging, has been a method of joining metals used since ancient times and is a staple of traditional blacksmithing. Forge welding is versatile, being able to join a host of similar and dissimilar metals. With the invention of electrical welding and gas welding methods during the Industrial Revolution, manual forge-welding has been largely replaced, although automated forge-welding is a common manufacturing process.
In materials science, quenching is the rapid cooling of a workpiece in water, gas, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, from occurring. It does this by reducing the window of time during which these undesired reactions are both thermodynamically favorable and kinetically accessible; for instance, quenching can reduce the crystal grain size of both metallic and plastic materials, increasing their hardness.
Case-hardening or Carburization is the process of introducing carbon to the surface of a low carbon iron or much more commonly low carbon steel object in order to enable the surface to be hardened.
Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys. Tempering is usually performed after hardening, to reduce some of the excess hardness, and is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air. The exact temperature determines the amount of hardness removed, and depends on both the specific composition of the alloy and on the desired properties in the finished product. For instance, very hard tools are often tempered at low temperatures, while springs are tempered at much higher temperatures.
Tamahagane (玉鋼) is a type of steel made in the Japanese tradition. The word tama means 'precious', and the word hagane means 'steel'. Tamahagane is used to make Japanese swords, daggers, knives, and other kinds of tools.
Knife making is the process of manufacturing a knife by any one or a combination of processes: stock removal, forging to shape, welded lamination or investment cast. Typical metals used come from the carbon steel, tool, or stainless steel families. Primitive knives have been made from bronze, copper, brass, iron, obsidian, and flint.
Bladesmithing is the art of making knives, swords, daggers and other blades using a forge, hammer, anvil, and other smithing tools. Bladesmiths employ a variety of metalworking techniques similar to those used by blacksmiths, as well as woodworking for knife and sword handles, and often leatherworking for sheaths. Bladesmithing is an art that is thousands of years old and found in cultures as diverse as China, Japan, India, Germany, Korea, the Middle East, Spain and the British Isles. As with any art shrouded in history, there are myths and misconceptions about the process. While traditionally bladesmithing referred to the manufacture of any blade by any means, the majority of contemporary craftsmen referred to as bladesmiths are those who primarily manufacture blades by means of using a forge to shape the blade as opposed to knifemakers who form blades by use of the stock removal method, although there is some overlap between both crafts.
Induction hardening is a type of surface hardening in which a metal part is induction-heated and then quenched. The quenched metal undergoes a martensitic transformation, increasing the hardness and brittleness of the part. Induction hardening is used to selectively harden areas of a part or assembly without affecting the properties of the part as a whole.
In swordsmithing, hamon (刃文) is a visible effect created on the blade by the hardening process. The hamon is the outline of the hardened zone which contains the cutting edge. Blades made in this manner are known as differentially hardened, with a harder cutting edge than spine. This difference in hardness results from clay being applied on the blade prior to the cooling process (quenching). Less or no clay allows the edge to cool faster, making it harder but more brittle, while more clay allows the center and spine to cool slower, thus retaining its resilience.
Japanese swordsmithing is the labour-intensive bladesmithing process developed in Japan beginning in the sixth century for forging traditionally made bladed weapons (nihonto) including katana, wakizashi, tantō, yari, naginata, nagamaki, tachi, nodachi, ōdachi, kodachi, and ya (arrow).
Honyaki (本焼) is the name for the Japanese traditional method of metalwork construction most often seen in kitchen knives by forging a blade, with a technique most similar to the tradition of nihonto, from a single piece of high-carbon steel covered with clay to yield upon quench a soft, resilient spine, a hamon, and a hard, sharp edge. Honyaki as a term alone can refer to either mizu honyaki (water-quench) or abura honyaki. The goal is to produce a sharper, longer lasting edge than is usually achievable with the lamination method. The term has been adapted to describe high-end mono-stainless in Japan and carbon blades by non-Japanese bladesmiths that have a hamon but are made with Western steel, heat treat, equipment, finishing, and design.
A katana is a Japanese sword characterized by a curved, single-edged blade with a circular or squared guard and long grip to accommodate two hands. Developed later than the tachi, it was used by samurai in feudal Japan and worn with the edge facing upward. Since the Muromachi period, many old tachi were cut from the root and shortened, and the blade at the root was crushed and converted into a katana. The specific term for katana in Japan is uchigatana (打刀) and the term katana (刀) often refers to single-edged swords from around the world.
