Metals processes

Case hardening or surface hardening is the process of hardening the surface of steel whilst leaving the interior unchanged. The idea behind case hardening is to have two different types of steel in the same item. This allows a relatively soft, tough core of a component to be combined with a hard (but potentially brittle) surface. Case hardening improves the wear resistance of machine parts without affecting the tough interior of the parts. Many processes are available for surface hardening. ...more on Wikipedia about "Case hardening"

Differential hardening is a method used in forging swords and knives to increase the hardness of the edge without making the whole blade brittle. To achieve this, the edge is cooled more rapidly than the spine by adding an heat insulator to the spine before quenching. Clay or another material is used for insulation. ...more on Wikipedia about "Differential hardening"

Electropolishing, sometimes called reverse electroplating, is an electrochemical process which polishes a metal surface by removing a microscopic amount of material from the work piece. ...more on Wikipedia about "Electropolishing"

Grain refinement is a set of techniques used in metallurgy to ensure that the crystallites (grains) that make up a metallic object are sufficiently small. One common technique is to induce a very small fraction of the melt to solidify at a much higher temperature than the rest; this will generate seed crystals that act as a template when the rest of the material falls to its (lower) melting temperature and begins to solidify. Since a huge number of minuscule seed crystals are present, a nearly equal number of crystallites result, and the size of any one grain is limited. ...more on Wikipedia about "Grain refinement"

Heat Treatment is a group of manufacturing techniques used to alter the hardness and toughness of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. ...more on Wikipedia about "Heat treatment"

Knurling is a manufacturing process, typically conducted on a lathe, whereby a visually-attractive diamond-shaped (criss-cross) pattern is cut or rolled into metal. This pattern allows human hands or fingers to get a better grip on the knurled object than would be provided by the originally-smooth metal surface. Occasionally, the knurled pattern is a series of straight ridges or a helix of "straight" ridges rather than the more-usual criss-cross pattern. ...more on Wikipedia about "Knurling"

Plated ware are articles chiefly intended for tableware use consisting of an inferior metal or alloy covered by one of the precious metals, with the object of giving them the appearance of gold or silver. Before the introduction of electroplating the method employed for silver plating, the invention of which in 1742 is associated with the name of Thomas Bolsover, of Sheffield, was to fuse or burn together, by a flux of borax, a thin sheet of silver on each side of an ingot of base metal, generally copper, or German silver, which is an alloy of copper. The silver plates were firmly wired to the ingot, which was then placed in a heated furnace and brought nearly to the fusing point of the silver. The artisan knew the exact moment to withdraw the ingot. When cold it was rolled down to a sheet, and from such sheets silver-plated articles were made. Articles like dish covers were originally only silver-plated on one side, and after being worked into shape were tinned inside with pure tin. In Birmingham, bar-copper was the base metal used; when bare of silver this showed blood red. The Sheffield manufacturers, on the other hand, used shot-copper mixed with brass, an alloy of copper and zinc, in the proportion of 4 or 6 to 1. In this way they got rid of the redness of the copper and rendered it harder, and their product is the old Sheffield plate that has become famous all over the world. This method of plating rapidly declined with the introduction of the newer process of electro-plating, by which it has been superseded. Plating with nickel is extensively used for bedsteads and other articles of upholstery, and for various parts of bicycles, steamships, railway carriages and steel sheets are also plated with nickel for cooking purposes, and iron is plated with brass. ...more on Wikipedia about "Plated ware"

Precipitation hardening, also called Age hardening, is a heat treatment technique used to strengthen malleable materials, especially non-ferrous alloys including most structural alloys of aluminium and titanium. It relies on changes in solid solubility with temperature to produce fine particles of an impurity phase, which impede the movement of dislocations. Since dislocations are often the dominant carriers of plasticity, this serves to harden the material. Just as the formation of ice in air can produce clouds, snow, or hail, depending upon the thermal history of a given portion of the atmosphere, precipitation in solids can produce many different sizes of particles, which have radically different effects. Unlike ordinary tempering, alloys must be kept at elevated temperature for hours to allow precipitation to take place. This time delay is called ageing. ...more on Wikipedia about "Precipitation strengthening"

Shot peening is a process used to produce a decorative finish and to modify mechanical properties of metals. It entails impacting a surface with shot (round metallic particles) with force sufficient to create dimples and with enough shot that those dimples overlap. It is similar to sandblasting, except that it operates by the mechanism of plasticity (physics) rather than abrasion: each particle functions as a ball-peen hammer. In practice, this means that less material is removed by the process, and less dust created. ...more on Wikipedia about "Shot peening"

Chemical reduction, or smelting, is a form of extractive metallurgy. The main use of smelting is to produce iron and steel from iron ore. Smelting is also used to extract copper and other base metals from their raw ores. ...more on Wikipedia about "Smelting"

Swaging is a metal forming technique in which the metal is plastically deformed to its final shape using high pressures. Swaging differs from forging in that the metal is cold worked. The term swage can apply to the process of swaging, a die used for swaging, or a tool used to swage. ...more on Wikipedia about "Swage"

Tempering is a heat treatment technique for metals and alloys, most often the toughening of martensitic steel. Most steel blades (from knives to swords) are hardened by quenching (which produces a martensitic transformation), but this hardening effect generally must be reduced by tempering to avoid brittleness. ...more on Wikipedia about "Tempering"

Tinning is the process of making tin-plate, which consists of sheets of iron or steel that have been thinly coated with tin by being dipped in a molten bath of that metal. Terne-plate is a similar product, but the bath is not of tin, but of tin and lead mixed, the latter metal constituting from 7.59% of the whole; it has not the bright luster of tin-plate, whence its name, from terne, dull, tarnished. The sheets employed in the manufacture are known as black plates, and are now of steel, either Bessemer steel or open-hearth. Formerly iron was used, and was of two grades, coke iron and charcoal iron; the latter, being the better, received a heavier coating of tin, and this circumstance is the origin of the terms coke plates and charcoal plates by which the quality of tin-plate is still designated, although iron is no longer used. Tin-plate is consumed in enormous quantities for the manufacture of the tin cans in which preserved meat, fish, fruit, biscuits, cigarettes and numerous other products are packed, and also for the household utensils of various kinds made by the tinsmith or silversmith; terne-plates, which began to be produced in England about the middle of the 19th century are widely employed in the United States for roofing purposes. ...more on Wikipedia about "Tinning"

Titanium nitride ( ) is an extremely hard (~85 Rockwell C Hardness or ~2500 Vickers Hardness)1, ceramic material, often used as a coating on titanium alloy, steel, carbide, and aluminum components to improve the substrate's surface properties. ...more on Wikipedia about "Titanium nitride"

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