 A replica Colt 1873 revolver, showing case hardening colors on the frame Case hardening or surface hardening is the process of hardening the surface of a metal, often a low carbon steel, by infusing elements into the material's surface, forming a thin layer of a harder alloy. Case hardening is usually done after the part in question has been formed into its final shape, but can also be done to increase the hardening element content of bars to be used in a pattern welding or similar process. Image File history File linksMetadata Download high-resolution version (966x663, 54 KB) Work by Rama File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Firearm Colt Single Action Army handgun Case hardening Metadata This file contains additional information, probably...
Image File history File linksMetadata Download high-resolution version (966x663, 54 KB) Work by Rama File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Firearm Colt Single Action Army handgun Case hardening Metadata This file contains additional information, probably...
Look up hardness in Wiktionary, the free dictionary. ...
Carbon steel, also called plain carbon steel, is a metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties. ...
An alloy is a homogeneous mixture of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ...
Pattern welded pocket knife 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. ...
History
Early iron smelting made use of bloomeries, which produced two layers of metal, one with a very low carbon content that is worked into wrought iron, and the rest a high carbon cast iron. Since the high carbon iron is hot short, meaning it fractures and crumbles when forged, it was not useful without more smelting. The wrought iron, with nearly no carbon in it, was very malleable and ductile, but not very hard. General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ...
A bloomery is a type of furnace once widely used for smelting iron from its oxides. ...
A wrought iron railing in Troy, New York. ...
Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon (alloys with less carbon are carbon steel by definition). ...
{Unreferenced|date=March 2007}} The forge or smithy is the workplace of a smith or a blacksmith. ...
Malleability is a physical property of matter, signifying its capability of deformation, especially by hammering or rolling. ...
Ductility is the physical property of being capable of sustaining large plastic deformations without fracture (in metals, such as being drawn into a wire). ...
Case hardening involved packing the iron in a substance high in carbon, and heating it in that environment to encourage carbon to migrate into the surface of the iron. This formed a thin layer of higher carbon steel on the surface, with the carbon content gradually decreasing further from the surface. The resulting product had much of the toughness of the softer iron core, with the hardness and wear resistance of the outer steel.
The traditional method of applying the carbon to the surface of the iron involved packing the iron in a mixture of ground bone and charcoal or a combination of leather, hooves, salt and urine, all inside a well-sealed box. The resulting package is then heated to a high temperature, but still under the melting point of the iron, and left at that temperature for a length of time. The longer the package is held at the high temperature, the deeper the carbon will diffuse into the surface. Different depths of hardening would be needed for different purposes; sharp tools would need deep hardening to allow them to be ground and resharpened without exposing the soft core, while machine parts like gears might need only a shallow hardening for increased wear resistance. Grays Anatomy illustration of a human femur. ...
Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. ...
Modern leather-working tools Leather is a material created through the tanning of hides and skins of animals, primarily cattlehide. ...
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For other uses, see Salt (disambiguation). ...
This article or section is in need of attention from an expert on the subject. ...
The resulting case hardened part may show a distinct coloration on the surface. The iron darkens significantly, and shows a mottled pattern of black, blue and purple caused by the various compounds formed by impurities in the bone and charcoal. This oxide surface works similar to blueing, providing some degree of corrosion reistance, in addition to being considered by many to be a very attractive finish. Case coloring refers to this pattern, and is commonly encountered as a decorative finish on replica firearms such as those patterned after single action Colt revolvers and lever action rifles. Bluing can refer to either of these: Bluing is a steel finishing process. ...
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A Glock 22 hand-held firearm with internal laser sight and mounted flashlight, surrounded by hollowpoint ammunition. ...
Modern copy of the Colt Single Action Army handgun Also known as the Colt Peacemaker or Single Action Army, the most exotic of which being the Black Powder model, the Colt Single Action Army handgun is a single action revolver holding 6 rounds of ammunition, that was designed for the...
rEVOLVEr (2004) is the fourth studio album release by Swedish thrash metal band The Haunted. ...
A lever-action is a type of firearm which uses a lever located around the trigger guard area (often including the trigger guard itself) to load fresh cartridges into the chamber of the barrel when the lever is cranked. The most famous of such lever-action firearms are the Martini...
With modern steelworking techniques, it is possible to make homogenous steels of low to high carbon content, removing much of the original motivation for case hardening. However, the heterogeneous nature of case hardened steel may still be desirable, as it provides a combination of hardness and toughness that cannot readily be matched by homogenous alloys.
Chemistry Carbon itself is solid at case-hardening temperatures and so is immobile. Transport to the surface of the steel was as gaseous carbon monoxide, generated by the breakdown of the carburising compound and the oxygen packed into the sealed box. This takes place with pure carbon, but unworkably slowly. Although oxygen is required for this process it's re-circulated through the CO cycle and so can be carried out inside a sealed box. The sealing is necessary to stop the CO either leaking out, or being oxidised to CO2 by excess outside air. Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ...
Adding an easily decomposed carbonate "energiser" such as barium carbonate breaks down to BaO + CO2 and this encourages the reaction Barium carbonate (BaCO3), also known as witherite, is a chemical compound used in rat poison, bricks and cement. ...
- C (from the donor) + CO2 <—> 2 CO
increasing the overall abundance of CO and the activity of the carburising compound.
It's 'common knowledge' that case-hardening was done with bone, but this is misleading. Although bone was used, the main carbon donor was hoof and horn. Bone contains some carbonates, but is mainly calcium phosphate (as hydroxylapatite). This doesn't have the beneficial effect on encouraging CO production and it can also supply phosphorus as an impurity into the steel alloy. Common knowledge is what everybody knows, usually with reference to the community in which the term is used. ...
Hydroxylapatite is a naturally occurring form of calcium apatite with the formula Ca5(PO4)3(OH), but is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two molecules. ...
General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ...
Modern use Both carbon and alloy steels are suitable for case-hardening; typically mild steels are used, with low carbon content, usually less than 0.3% (see plain-carbon steel for more information). These mild steels are not normally hardenable due to the low quantity of carbon, so the surface of the steel is chemically altered to increase the hardenability. Case hardened steel is usually formed by diffusing carbon (carburization), nitrogen (nitridization) and/or boron (boriding) into the outer layer of the steel at high temperature, and then heat treating the surface layer to the desired hardness. Carbon steel, also called plain carbon steel, is a metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties. ...
Steel framework Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ...
General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ...
Plain-carbon steel is a metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties. ...
Carburization (often referred to as carburizing) is the name of the process by which carbon is introduced into a metal. ...
General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...
Nitridization, also known as nitriding, is a process which introduces nitrogen in the surface of a material. ...
General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Standard atomic weight 10. ...
It has been suggested that this article or section be merged into boron. ...
The term case hardening is derived from the practicalities of the carburization process itself, which is essentially the same as the ancient process. The steel work piece is placed inside a case packed tight with a carbon-based case hardening compound. This is collectively known as a carburizing pack. The pack is put inside a hot furnace for a variable length of time. Time and temperature determines how deep into the surface the hardening extends. However, the depth of hardening is ultimately limited by the inability of carbon to diffuse deeply into solid steel, and a typical depth of surface hardening with this method is up to 1.5 mm. Other techniques are also used in modern carburizing, such as heating in a carbon rich atmosphere. Small items may be case hardened by repeated heating with a torch and quenching in a carbon rich medium, such as the commercial product Kasenit / Casenite. General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ...
Soot, also called lampblack or carbon black, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers insides of smoke saunas and other surfaces exposed to smoke—especially from the combustion of carbon-rich organic fuels in the lack...
Applications Parts that are subject to high pressures and sharp impacts are still commonly case hardened. Examples include firing pins and rifle bolt faces, or engine camshafts. In these cases, the surfaces requiring the hardness may be hardened selectively, leaving the bulk of the part in its original tough state. The firing pin is a very hard steel rod with a one small, rounded end for striking the primer of a cartridge. ...
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Computer animation of a camshaft The camshaft is an apparatus often used in piston engines to operate poppet valves. ...
Firearms were a common item case hardened in the past, as they required precision machining best done on low carbon alloys, yet needed the hardness and wear resistance of a higher carbon alloy. Many modern replicas of older firearms, particularly single action revolvers, are still made with case hardened frames, or with case coloring, which simulates the mottled pattern left by traditional charcoal and bone case hardening. In a single action gun, the triggers only function is to release the hammer. ...
rEVOLVEr (2004) is the fourth studio album release by Swedish thrash metal band The Haunted. ...
Another common application of case hardening is on screws, particularly self-drilling screws. In order for the screws to be able to drill, cut and tap into other materials like steel, the drill point and the forming threads must be harder than the material(s) that it is drilling into. However if the whole screw is uniformly hard, it will become very brittle and it will break easily. This is overcome by ensuring that only the case is hardened and the core remains relatively soft. For screws and fasteners, case hardening is less complicated as it is achieved by heating and quenching in the form of heat treatment This page is a candidate to be moved to Wiktionary. ...
Case hardening in wood The term case hardened is also used to describe lumber or timber that has been improperly kiln-dried. If dried too quickly, wood shrinks heavily on the surface, compressing its still damp interior. This results in unrelieved stress. Case hardened wood may warp considerably and potentially dangerously when the stress is released by sawing. Timber in storage for later processing at a sawmill Lumber or Timber is a term used to describe wood, either standing or that has been processed for use—from the time trees are felled, to its end product as a material suitable for industrial use—as structural material for construction...
Timber in storage for later processing at a sawmill Timber is a term used to describe wood, either standing or that has been processed for use—from the time trees are felled, to its end product as a material suitable for industrial use—as structural material for construction or wood...
Charcoal Kilns, California Gold Kiln, Victoria, Australia Hop kiln. ...
Trunks A tree trunk as found at the Veluwe, The Netherlands Wood is a solid material derived from woody plants, notably trees but also shrubs. ...
Stress is the internal distribution of force per unit area that balances and reacts to external loads applied to a body. ...
Portable saw A saw is a tool for cutting wood or other material, consisting of a serrated blade (a blade with the cutting edge dentated or toothed) and worked either by hand or by steam, water, electric or other power. ...
See also Carburization is the name of the process by which carbon is introduced into a metal. ...
Shot peening is a process used to produce a decorative finish and to modify mechanical properties of metals. ...
A differential hardening is a method used in forging swords and knives to increase the hardness of the edge. ...
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