Hardening may refer to Hardening botany , the process by which a plant survives temperatures below the freezing point of water Hardening computing , the process of securing a system Hardening metallurgy , the strengthening of metal alloys by heat treatment Case hardening , the process of hardening the surface of a metal by infusing elements into the material s surface forming a thin layer of a harder alloy G hardening, the preparation of an object for not getting damaged when subjected to a high g force a synonym for sclerotization occurring in arthropods See also Harden disambiguation Hardness disambig ... more details
Target hardening is a term chiefly used by police officers and those working in security, referring to the strengthening of the security of building in order to reduce or minimising the risk of attack or theft . ref cite web url https www.businesscrimedirect.org.uk page.asp?pagekey 115 title Target Hardening publisher Business Crime Direct accessdate 2007 11 30 ref ref name vanc cite web url http www.city.vancouver.bc.ca police crimeprevention HSTarget.htm title Target Hardening publisher Vancouver Police Department accessdate 2007 11 30 Dead link date October 2010 bot H3llBot ref It is believed that a strong, visible defense will deter or delay an attack . ref name approaches cite web url http www.apsu.edu oconnort 3440 3440lect06a.htm title Approaches to Target Hardening accessdate 2007 11 30 publisher Austin Peay State University author Tom O Connor archiveurl http web.archive.org web 20070712144216 http www.apsu.edu oconnort 3440 3440lect06a.htm archivedate 2007 07 12 ref In terms of home security , target hardening may also be referred to as crime prevention through environmental design . This can include ensuring all doors and windows are closed and securely locked, removing any tree s or shrub bush es that could offer suitable hiding places or could be used to climb to a higher level of the property. ref name vanc However, for a business, taking target hardening too far can ... murray research cpted target hardening default.htm title Target Hardening publisher Blue Ridge Community ..., target hardening refers to ensuring strategic or tactical assets are secured against enemy attack ... Library CrimePrevention Volume 2006 03 20weidner.pdf Target Hardening at a New York ... 203 Strategic 20Assessment 20Project Ellis.pdf Target Hardening the City of Orlando http web.archive.org web 20030514055457 http www.e doca.net Resources Articles The Target Hardening Trap.htm The Target Hardening Trap law enforcement stub Category Targeting warfare ... more details
Unreferenced date March 2009 In computing , hardening is usually the process of securing a system by reducing its surface of vulnerability. A system has a larger vulnerability surface the more that it does in principle a single function system is more secure than a multipurpose one. Reducing available vectors of attack typically includes the removal of unnecessary software, unnecessary user name username s or logging computer security logins and the disabling or removal of unnecessary Daemon computer software services . There are various methods of hardening Unix and Linux systems. This may involve, among other measures, applying a Patch computing patch to the kernel computer science kernel such as Exec Shield or PaX closing open TCP and UDP port network port s and setting up intrusion detection system s, firewall networking firewalls and intrusion prevention system s. There are also hardening script computer programming scripts and tools like Bastille Linux , JASS http sun.com software security jass for Solaris operating system Solaris systems and Apache PHP Hardener http www.syhunt.com hardener that can, for example, deactivate unneeded features in configuration files or perform various other protective measures. See also Computer security Computer network security Network security policy Security Enhanced Linux External links http www.colorado.edu cns security awareness hardening IT Security Topic Hardening www.colorado.edu pdflink http www.globalsecurity.org military library report 1997 harden.pdf Hardening Your Computing Assets www.globalsecurity.org Category Computer security procedures de H rten Computer fr Durcissement informatique it Hardening pt Hardening ... more details
Merge to Wood drying discuss Talk Wood drying Merger proposal date May 2011 Fire hardening is the process of removing moisture from wood by slowly and lightly charring it over a fire . This makes a point, like that of a spear , or an edge, like that of a knife, more durable. See also Wood working Woodworking DEFAULTSORT Fire Hardening Category Timber preparation Weapon stub ... more details
Please do not add information about the mechanism of hardening to this article see hardness instead. Hardening is a metallurgical and metalworking process used to increase the hardness of a metal. The hardness of a metal is directly proportional to the uniaxial yield stress at the location of the imposed strain. A harder metal will have a higher resistance to plastic deformation than a less hard metal. Processes The five hardening processes are The Hall Petch method is used to change the grain size in a material, which can affect the dislocation density. Smaller grain size will make the material harder, but if the grains get too small the hardness can actually decrease. In work hardening also referred to as strain or cold hardening the material is strained past its yield point. The work done on the material adds energy and has the ability to move and generate dislocations. This process usually takes place at a temperature below the materials recrystallization temperature. In solid solution strengthening , an alloying element is added to the material desired to be strengthened, and together they form a solid solution . Different alloying elements can be used to cause either a substitutional or an interstitial solid solution. Precipitation hardening is a process where impure particles are distributed throughout the metal. This is achieved by first heating the metal above its phase transition temperature and then rapidly cooling the metal. Particles of the second phase become trapped and form anchor points to impede the movement of dislocations. Precipitation hardening is one of the most commonly used techniques for the hardening of metal alloys. In steels, a similar method is referred to as a martensitic transformation. In this transformation, austenite is rapidly cooled off ... phase of steel. Martensitic transformation , more commonly known as quenching and tempering . All hardening ... lattice that act as barriers to slip. Applications Material hardening is required for many ... more details
and more impact resistant core. Process Diffusion hardening is performed by completely surrounding .... Types Diffusion hardening can be done in many different ways to achieve different hardnesses and different surface finishes on metal parts. Some of the different diffusion hardening operations include ... , and Toyota diffusion . While diffusion hardening is performed mainly on steel parts and carbon is mainly the element used for diffusion, diffusion hardening can also be performed with other diffusion ... and diffusion elements used, diffusion hardening processes differ in the temperature required for diffusion ... is inefficient. All these things must come into consideration when choosing a diffusion hardening process. References Diffusion Treatment Hardening. eFunda. Retrieved 19 April 2008. http www.efunda.com Surface Hardening of Steels. Key to Metals. Retrieved 19 April 2008. http steel.keytometals.com ... more details
Differential hardening is a method used in forging sword s and knife 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 a heat insulator to the spine before quenching . Clay or another material is used for insulation. It can also be achieved by carefully pouring water perhaps already heated onto the edge of a blade as is the case with the manufacture of some kukri . This technique is mainly used in the Chinese jian and the katana , the traditional Japan ese sword, and the khukuri , the traditional Nepal ese knife. Most blades made with this technique have visible temper lines. Another process, often referred to as differential hardening, but in reality differential tempering can also be obtained by quenching the object uniformly, then differentially tempering one part of it with a torch or some other directed heat source. The heated portion of the metal is softened by this process. http www.primitiveways.com pt knives 1.html See also Case hardening Shot peening External links http www.engnath.com claytemp.htm Claying blades Differential hardening with clay Category Metal heat treatments metalworking stub ... more details
For the woodworking term case hardening woodworking Image Peacemaker p1030061.jpg thumb right A replica Colt 1873 revolver, showing case hardening colors on the frame Case hardening or surface hardening is the process of Hardening metallurgy 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 ... be done to increase the hardening element content of bars to be used in a pattern welding or similar process. The term face hardening is also used to describe this technique, when discussing modern ... malleable and ductile , but not very hard. Case hardening involves packing the low carbon iron within ... depths of hardening is desirable for different purposes sharp tools need deep hardening to allow ... only shallow hardening for increased wear resistance. The resulting case hardened part may show distinct ... for case hardening. However, the heterogeneous nature of case hardened steel may still be desirable ... matched by homogeneous alloys. Chemistry Carbon itself is solid at case hardening temperatures and so ... Metallurgy pages 474 ref It s common knowledge that case hardening was done with bone, but this is misleading .... Modern use Both carbon and alloy steel s are suitable for case hardening typically mild steels ... case hardening is derived from the practicalities of the carburization process itself, which is essentially ... with a carbon based case hardening compound. This is collectively known as a carburizing pack. The pack ... 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 ... hsx stories 2006 03 01 hmn feature20.html Case Hardening in a Home Garage Hemmings Sports & Exotic Car MARCH 1, 2006 BY CRAIG FITZGERALD ref Processes Flame and induction hardening Main Induction hardening Flame or induction hardening are processes in which the surface of the steel ... more details
Unreferenced stub auto yes date December 2009 Cold hardening is the physiological and biochemical process by which an organism prepares for cold weather . Plants Image Plant cell structure svg.svg thumb 200px Schematic of typical plant cell During the winter months, as the leaves fall off deciduous species and the temperature drops, the cold forces a stop to water movement in plant s. Freezing water can also cause irreversible damage to Cell biology cell s in plants as water solidifies. To guard against this, plants prepare for winter with a process called cold hardening. The process begins as the cell membrane permeability undergoes a change that permits water to seep into the intracellular voids. In addition, the cells store large amounts of sugars in the protoplasm , decreasing its freezing point. Cold hardening protects plants from both chilling injury and freezing injury. Chilling injury occurs at 0 10 degrees Celsius, as a result of membrane damage, metabolic changes, and toxic buildup. Symptoms include wilting, water soaking, necrosis , chlorosis , ion leakage, and decreased growth. Freezing injury occurs at temperatures below 0 degrees Celsius. Symptoms of extracellular freezing include structural damage, dehydration, and necrosis. If intracellular freezing occurs, it will lead to death. Freezing injury is a result of lost permeability, plasmolysis, and post thaw cell bursting. See Also Hardening botany Cryobiology DEFAULTSORT Cold Hardening Category Physiology Ecology stub fr Ao tement ... more details
Hardening in botany is the process by which an individual plant becomes tolerant to the effects of freezing during a period of weeks to months. It is a three stage process. During the first stage, carbohydrates are translocated to the roots of the plant and cell membrane permeability increases. By the end of the first stage, the plant will be able to tolerate temperatures from 5 to 10 C. In the second stage, cell membranes are chemically altered, and this process will allow plants to survive temperatures of 20 C. In the third stage, which occurs in plants that survive at temperatures as low as 50 C, Cryopreservation Vitrification vitrification may occur. See also Antifreeze protein Cryopreservation Cryobiology Cold hardening References http books.google.com books?id itB5yKv7 rIC Plants in Agriculture 1992 Forbes and Watson botany stub Category Cryobiology Category Temperature Category Botany Category Plant physiology ca Enduriment bot nica ... more details
Orphan date May 2009 In the field of nuclear engineering , absorption hardening refers to an average increase in neutron temperature energy of the neutron population, caused by preferential neutron capture absorption of lower energy neutrons. This occurs because absorption cross sections typically increase for lower neutron energies. References Weston M. Stacey, Nuclear Reactor Physics, 2nd ed. Wiley VCH, 2007 Category Nuclear technology nuclear stub ar ... more details
Induction hardening is a form of heat treatment in which a metal part is heated by induction heating ... materials science hardness and brittleness of the part. Induction hardening is used to selectively ... Rudnev, p. 58. ref Definition A widely used process for the surface hardening of steel. The components ..., induction hardening is one of the most widely employed to improve component durability . It determines ... require high wear resistance. Wear resistance behavior of induction hardened parts depends on hardening ... the first surface hardening induction heating systems using motor generators. ref Rudnev, p ... of the induction hardening process and by the late 1950s many systems utilising motor generators ... shot hardening In single shot systems the component is held statically or rotated in the coil and the whole ... the desired result for example for flat face hardening of hammers, edge hardening complex shaped tools or the production of small gears. ref Rudnev, p. 249. ref In the case of shaft hardening a further ... hardening methods. In addition the ability to use coils which can create longitudinal current flow ... heated compared with a traverse approach. ref Rudnev, p. 250. ref Traverse hardening In traverse hardening ... spray or ring is utilised. Traverse hardening is used extensively in the production of shaft type ... in diameter or splines. It is normal when hardening round shafts to rotate the part during the process ... and the hardness value achieved. Equipment Power required Power supplies for induction hardening ... and the production method employed i.e. single shot hardening, traverse hardening or submerged hardening. In order to select the correct power supply it is first necessary to calculate the surface .... In the case of traverse hardening the circumference of the component is multiplied by the face width ... Induction heating systems for hardening are available in a variety of different operating frequencies ... and practicality. See also Case hardening Induction forging Induction heater Induction shrink fitting ... more details
Cryogenic hardening is a cryogenic heat treating process where the material is cooled to approximately convert 185 C 0 abbr on , usually using liquid nitrogen . It can have a profound effect on the mechanical properties of certain steel s, provided their composition and prior heat treatment are such that they retain some austenite at room temperature. It is designed to increase the amount of martensite in the steel s crystal structure, increasing its strength of materials strength and hardness , sometimes at the cost of toughness . Presently this treatment is being practiced over tool steels, high carbon, and high chromium steels to obtain excellent wear resistance. Recent research shows that there is precipitation of fine carbides eta carbides in the matrix during this treatment which imparts very high wear resistance to the steels. ref J.Y. Huang et al. Microstructure of cryogenic treated M2 tool steel. Material Science and Engineering A 339 2003 241 244. ref The transformation from austenite to martensite is mostly accomplished through quench ing, but in general it is driven farther and farther toward completion as temperature decreases. In higher alloy steels such as austenitic stainless steel , the onset of transformation can require temperatures much lower than room temperature. More commonly, an incomplete transformation occurs in the initial quench, so that cryogenic treatments merely enhance the effects of prior quenching. The transformation between these phases is instantaneous and not at all dependent upon diffusion , and also that this treatment causes more complete hardening rather than moderating extreme hardness, both of which make the term cryogenic tempering technically incorrect. Hardening can also be accomplished by cold work at cryogenic temperatures. The defects introduced by plasticity physics plastic deformation at these low temperatures are often ... changes that in some ways resemble the effects of shock hardening . While this process is more effective ... more details
Refimprove date March 2010 Shock hardening is a process used to strength of materials strengthen metals and alloy s, wherein a shock wave produces atomic scale defects in the material s crystal line structure. As in cold work , these defects interfere with the normal processes by which metallic materials yield plasticity physics plasticity , making materials stiffer, but more brittle . When compared to traditional cold work, such an extremely rapid process results in a different class of defect, producing a much harder material for a given change in shape. If the shock wave applies too great a force for too long, however, the rarefaction front that follows it can form voids in the material due to hydrostatic tension, weakening the material and often causing it to spall . Since voids wiktionary nucleation nucleate at large defects, such as oxide inclusion mineral inclusion s and grain boundary grain boundaries , high purity samples with a large grain size especially single crystals are able to withstand greater shock without spalling, and can therefore be made much harder. Shock hardening has been observed in many contexts Explosive forging uses the detonation of a explosive material Classification by type of explosion high explosive charge to create a shockwave. This effect is used to harden rail track Casting cast components ref The service life of Railroad switch frog frogs can be increased threefold when treated with this technique cite book last Meyers first Marc A. title Dynamic behavior of materials publisher John Wiley location New York year 1994 pages 5 382 570 isbn 9780471582625 ref and, coupled with the Misznay Schardin effect , in the operation of explosively formed penetrator explosively forged penetrators . Greater hardening can be achieved by using a lower ... is often quite short, meaning that good hardening can be achieved with little risk of spallation . Surface ... gas gun s have been used to study shock hardening. Although too labor intensive for widespread industrial ... more details
Refimprove date September 2009 Work hardening , also known as strain hardening or cold working , is the strength ... can only be strengthened via work hardening, such as pure copper and aluminum . ref harvnb Smith Hashemi 2006 p 246 . ref Work hardening may be desirable or undesirable depending on the context. An example of undesirable work hardening is during machining when early passes of a Cutting tool machining ... passes. An example of desirable work hardening is that which occurs in taxonomy of manufacturing ... to avoid work hardening a result of Deformation engineering Plastic deformation plastic deformation ... designed to minimize or evenly distribute flexure, which can lead to work hardening and in turn ... must be retired. Theory Before work hardening, the lattice of the material exhibits a regular ... date October 2009 Elastic and plastic deformation Main Deformation engineering Work hardening is a consequence ... studied. Work hardening occurs most notably for ductile materials such as metals. Ductility is the ability ... on the atomic scale. Increase of dislocations and work hardening Image Work HArd.png thumb 200px ... present. Increase in the number of dislocations is a quantification of work hardening ... occurs fracture. Quantification of work hardening The stress, math tau math , of dislocation ... specific to the material. As shown in Figure 1 and the equation above, work hardening has a half ... cavitation can also produce strain hardening. Additionally, jewelers will construct structurally sound ... mathematical descriptions of the work hardening phenomenon. Hollomon s equation is a power law relationship ... is the stress, K is the strength index, sub p sub is the plastic strain and n is the strain hardening ... hardening index can be described by math n frac d log sigma d log epsilon frac epsilon sigma frac d ... allows a determination of the rate of strain hardening at a given stress and strain math frac d sigma d epsilon n frac sigma epsilon , math This should be part of series on hardening techniques, including ... more details
Refimprove date February 2010 Precipitation hardening , also called age hardening , is a heat treatment technique used to increase the yield strength of malleable materials, including most structural alloys of aluminium , magnesium , nickel and titanium , and some stainless steel s. It relies on changes in solid solubility with temperature to produce fine particles of an impurity phase matter phase , which impede the movement of dislocation s, or defects in a crystal s crystal structure lattice . Since dislocations are often the dominant carriers of plasticity physics plasticity , this serves to harden the material. The impurities play the same role as the particle substances in particle reinforced composite materials. 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 chemistry precipitation in solids can produce many different sizes of particles, which have radically different properties. Unlike ordinary tempering , alloys must be kept at elevated temperature for hours to allow precipitation to take place. This time delay is called aging . Solution treatment and aging is sometimes abbreviated STA in metals specification specs and product certification certs . Note that two ... hardening via precipitation heat treatment is the main topic of discussion in this article ... and chromium needed for corrosion resistance in stainless steels means that traditional hardening ... can strengthen the steel by similar amounts in comparison to hardening and tempering. The strength ... for precipitation hardening Dislocations cutting through particles math tau frac pi r gamma .... These governing equations show that the precipitation hardening mechanism depends on the size ... precipitation hardening materials 2000 series aluminum alloys important examples 2024 aluminium ... positron laboratory Precipitation hardening of light alloys. Positron spectroscopy. Category ... more details
Citations missing date May 2009 Radiation hardening is a method of designing and testing electronic components and systems to make them resistant to damage or malfunctions caused by ionizing radiation particle radiation and high energy electromagnetic radiation , ref http www.accessscience.com abstract.aspx?id 566850&referURL http 3a 2f 2fwww.accessscience.com 2fcontent.aspx 3fsearchStr 3dRadiation 2bhardening 26id 3d566850, Radiation Hardening McGraws AccessScience ref such as would be encountered in outer space , high altitude flight, around nuclear reactor s, particle accelerators , during nuclear accident s or nuclear warfare . Most radiation hardened chips are based on their commercial equivalents, with some manufacturing and design variations that reduce the susceptibility to interference from electromagnetic radiation. Due to the extensive development and testing required to produce a radiation tolerant design of a microelectronics microelectronic chip, radiation hardened chips tend to lag behind the cutting edge of developments. Problems caused by radiation See also Radiation damage Environments with high levels of ionizing radiation create special design challenges. A single ... for the military aerospace markets employ various methods of radiation hardening. The resulting ... Radiation Effects Laboratories . Radiation hardening techniques Physical Hardened chips are often ... a hard reset to the system. This is considered a last resort to other methods of radiation hardening ... Exploration Rover Power and electronic systems Mars rovers Electromagnetic pulse hardening see TEMPEST ... a general backgrounder section on Sandia s manufacturing processes for radiation hardening of microelectronics ... Testing Services SEE , Sweden Radiation DEFAULTSORT Radiation Hardening Category Military communications Category Integrated circuits Category Avionics computers Radiation hardening Category Electronics ... defects fr Durcissement lectronique simple Radiation hardening ... more details
The strain hardening exponent also called strain hardening index , noted as n , is a materials constant which is used in calculations for Stress strain curve stress strain behaviour in work hardening . In the formula K sup n sup , represents the applied Stress physics stress on the material, is the Strain materials science strain and K is the strength coefficient. The value of the strain hardening exponent lies between 0 and 1. A value of 0 means that a material is a perfectly Plasticity physics plastic solid, while a value of 1 represents a 100 Elasticity physics elastic solid. Most metals have an n value between 0.10 and 0.50. Tabulation class wikitable Tabulation of n and K Values for Several Alloys ref Citation first William D last Callister, Jr. title Fundamentals of Materials Science and Engineering place United States of America publisher John Wiley & Sons edition 2nd year 2005 page 199 isbn 9780471470144 ref Material n K MPa Low carbon steel annealed 0.21 600 4340 steel alloy annealed 0.12 2650 304 stainless steel annealed 0.44 1400 Copper annealed 0.44 530 Naval brass annealed 0.21 585 2024 aluminum alloy heat treated T3 0.17 780 AZ 31B magnesium alloy annealed 0.16 450 References reflist External links http steel.keytometals.com Articles Art42.htm More complete picture about the strain hardening exponent in the stress strain curve on www.key to steel.com http engsci.unavoidable.ca bme210 A discourse on textbook prices by Kevin P. Siu engineering stub Category Mechanical engineering Category Solid mechanics ... more details
Case hardening is a weathering phenomenon of rock surface induration . It is observed commonly in felsic alkaline rocks, such as nepheline syenite , phonolite and trachyte pyroclastic rock s, as pyroclastic flow deposit, fine air fall deposits and vent filling pyroclastic deposits sedimentary rock s, as sandstone and mudstone . Image Amotoki CaseHardening 1 Principle En.jpg right thumb 150px Principle of case hardening Weathering process Chemical weathering alters the minerals constituent of rock surface. Decomposition of mafic and opaque minerals releases ions and colloids of iron, magnesium, calcium and sulphur. Alteration of feldspar s and feldspathoid s releases silica colloid. These materials are reached and transported by surface water. The remnant materials are highly aluminous and siliceous. They could have certain mechanical firmness of own minerals, however no cohesion. Therefore, physical disintegration of the rock takes place to form the surface. In certain cases, the weathered surface obtains mechanical firmness higher than subsurface. The reached materials dissolved in the surface infiltrates in the weathered surface and cement the silica aluminous remnant materials. The surface induration by means of this process is named case hardening ref Dorn, R.L. 2004. Case hardening ... Amotoki CaseHardening 3 Clast En.jpg right thumb 650px Case hardening on alkaline felsic rocks ... Escola de Minas, 60 3, 451 548 ref . The case hardening on trachytic clasts of volcanic breccia shows peculiar fabrics. The Mars scientific exploring machine Spirit has observed case hardening present ... ref Farmer, J.D. 2005. Case hardening of rocks on Mars evidence for water mediated weathering ..., paper 223 5, CD. ref . Mineral dissociation On the rock surface in the case hardening of alkaline felsic ... et al. 2007 References references DEFAULTSORT Case Hardening Of Rocks Category Geology Category Geological processes pt case hardening ... more details
The term drying agent has different meanings Desiccant for materials that absorb moisture and water Oil drying agent s for compounds that speed up the drying oil hardening of oils , often used in painting disambig ... more details
wiktionary forming Forming may refer to Forming song Forming song , a song by the Germs See also Cold forming or work hardening Roll forming Vacuum forming Thermoforming Form disambiguation Formation disambiguation disambig ... more details
Unreferenced auto yes date December 2009 A retarder is a chemical agent that slows down a chemical reaction . For example, retarders are used to slow the chemical Curing chemistry hardening of plastic materials such as wallboard , concrete , and adhesive s. Sugar water acts as a retarder for the curing of concrete. It can be used to retard the chemical hardening of the surface, so that the top layer can be washed off to expose the underlying aggregate composite aggregate . See also Accelerant DEFAULTSORT Retarder Chemistry Category Chemical reactions Chem stub de Verz gerungsplatte fa ... more details
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