487:
401 °F), will produce a slight reduction in hardness, but will primarily relieve much of the internal stresses. In some steels with low alloy content, tempering in the range of 260 and 340 °C (500 and 644 °F) causes a decrease in ductility and an increase in brittleness, and is referred to as the "tempered martensite embrittlement" (TME) range. Except in the case of blacksmithing, this range is usually avoided. Steel requiring more strength than toughness, such as tools, are usually not tempered above 205 °C (401 °F). Instead, a variation in hardness is usually produced by varying only the tempering time. When increased toughness is desired at the expense of strength, higher tempering temperatures, from 370 to 540 °C (698 to 1,004 °F), are used. Tempering at even higher temperatures, between 540 and 600 °C (1,004 and 1,112 °F), will produce excellent toughness, but at a serious reduction in strength and hardness. At 600 °C (1,112 °F), the steel may experience another stage of embrittlement, called "temper embrittlement" (TE), which occurs if the steel is held within the temperature range of temper embrittlement for too long. When heating above this temperature, the steel will usually not be held for any amount of time, and quickly cooled to avoid temper embrittlement.
483:, using methods such as immersing the hot steel in water, oil, or forced-air. The quenched steel, being placed in or very near its hardest possible state, is then tempered to incrementally decrease the hardness to a point more suitable for the desired application. The hardness of the quenched steel depends on both cooling speed and on the composition of the alloy. Steel with a high carbon content will reach a much harder state than steel with a low carbon content. Likewise, tempering high-carbon steel to a certain temperature will produce steel that is considerably harder than low-carbon steel that is tempered at the same temperature. The amount of time held at the tempering temperature also has an effect. Tempering at a slightly elevated temperature for a shorter time may produce the same effect as tempering at a lower temperature for a longer time. Tempering times vary, depending on the carbon content, size, and desired application of the steel, but typically range from a few minutes to a few hours.
952:
tempering carbon steel. This allows the steel to maintain its hardness in high-temperature or high-friction applications. However, this also requires very high temperatures during tempering, to achieve a reduction in hardness. If the steel contains large amounts of these elements, tempering may produce an increase in hardness until a specific temperature is reached, at which point the hardness will begin to decrease. For instance, molybdenum steels will typically reach their highest hardness around 315 °C (599 °F) whereas vanadium steels will harden fully when tempered to around 371 °C (700 °F). When very large amounts of solutes are added, alloy steels may behave like precipitation-hardening alloys, which do not soften at all during tempering.
596:, or by fire, so holding the work at exactly the right temperature for the correct amount of time was usually not possible. Tempering was usually performed by slowly, evenly overheating the metal, as judged by the color, and then immediately cooling, either in open air or by immersing it in water. This produced much the same effect as heating at the proper temperature for the right amount of time, and avoided embrittlement by tempering within a short time period. However, although tempering-color guides exist, this method of tempering usually requires a good amount of practice to perfect, because the final outcome depends on many factors, including the composition of the steel, the speed at which it was heated, the type of heat source (
508:
the steel, thereby increasing the toughness to a more desirable point. Cast steel is often normalized rather than annealed, to decrease the amount of distortion that can occur. Tempering can further decrease the hardness, increasing the ductility to a point more like annealed steel. Tempering is often used on carbon steels, producing much the same results. The process, called "normalize and temper", is used frequently on steels such as 1045 carbon steel, or most other steels containing 0.35 to 0.55% carbon. These steels are usually tempered after normalizing, to increase the toughness and relieve internal stresses. This can make the metal more suitable for its intended use and easier to
789:
for austempering; to just above the martensite start temperature. The metal is then held at this temperature until the temperature of the steel reaches an equilibrium. The steel is then removed from the bath before any bainite can form, and then is allowed to air-cool, turning it into martensite. The interruption in cooling allows much of the internal stresses to relax before the martensite forms, decreasing the brittleness of the steel. However, the martempered steel will usually need to undergo further tempering to adjust the hardness and toughness, except in rare cases where maximum hardness is needed but the accompanying brittleness is not. Modern
613:
837:
and higher. In the third stage, ε-carbon precipitates into cementite, and the carbon content in the martensite decreases. If tempered at higher temperatures, between 650 °C (1,202 °F) and 700 °C (1,292 °F), or for longer amounts of time, the martensite may become fully ferritic and the cementite may become coarser or more spherical. In spheroidized steel, the cementite network breaks apart and recedes into rods or spherical-shaped globules, and the steel becomes softer than annealed steel; nearly as soft as pure iron, making it very easy to
726:
the tempering colors form and slowly creep toward the edge. The heat is then removed before the light-straw color reaches the edge. The colors will continue to move toward the edge for a short time after the heat is removed, so the smith typically removes the heat a little early, so that the pale yellow just reaches the edge, and travels no farther. A similar method is used for double-edged blades, but the heat source is applied to the center of the blade, allowing the colors to creep out toward each edge.
695:
31:
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774:
below 350 °C, and is stronger but much more brittle. In either case, austempering produces greater strength and toughness for a given hardness, which is determined mostly by composition rather than cooling speed, and reduced internal stresses which could lead to breakage. This produces steel with superior impact resistance. Modern punches and chisels are often austempered. Because austempering does not produce martensite, the steel does not require further tempering.
238:, dating from around 1200 to 1100 BC. The process was used throughout the ancient world, from Asia to Europe and Africa. Many different methods and cooling baths for quenching have been attempted during ancient times, from quenching in urine, blood, or metals like mercury or lead, but the process of tempering has remained relatively unchanged over the ages. Tempering was often confused with quenching and, often, the term was used to describe both techniques. In 1889, Sir
444:, to achieve any number of a combination of properties, making the steel useful for a wide variety of applications. Tools such as hammers and wrenches require good resistance to abrasion, impact resistance, and resistance to deformation. Springs do not require as much wear resistance, but must deform elastically without breaking. Automotive parts tend to be a little less strong, but need to deform plastically before breaking.
634:, which produces colors on the surface. As the thickness of this layer increases with temperature, it causes the colors to change from a very light yellow, to brown, to purple, and then to blue. These colors appear at very precise temperatures and provide the blacksmith with a very accurate gauge for measuring the temperature. The various colors, their corresponding temperatures, and some of their uses are:
604:), the cooling rate, oil films or impurities on the surface, and many other circumstances which vary from smith to smith or even from job to job. The thickness of the steel also plays a role. With thicker items, it becomes easier to heat only the surface to the right temperature, before the heat can penetrate through. However, very thick items may not be able to harden all the way through during quenching.
255:, one may encounter many terms that have very specific meanings within the field, but may seem rather vague when viewed from the outside. Terms such as "hardness," "impact resistance," "toughness," and "strength" can carry many different connotations, making it sometimes difficult to discern the specific meaning. Some of the terms encountered, and their specific definitions are:
829:," between the crystals, providing less-stressful areas for the carbon atoms to relocate. Upon heating, the carbon atoms first migrate to these defects and then begin forming unstable carbides. This reduces the amount of total martensite by changing some of it to ferrite. Further heating reduces the martensite even more, transforming the unstable carbides into stable cementite.
758:
870:, may increase the embrittlement, or alter the temperature at which it occurs. This type of embrittlement is permanent, and can only be relieved by heating above the upper critical temperature and then quenching again. However, these microstructures usually require an hour or more to form, so are usually not a problem in the blacksmith method of tempering.
83:
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hours. The heating is followed by a slow cooling rate of around 10 °C (18 °F) per hour. The entire process may last 160 hours or more. This causes the cementite to decompose from the ledeburite, and then the carbon burns out through the surface of the metal, increasing the malleability of the cast iron.
927:
Most alloying elements (solutes) have the benefit of not only increasing hardness, but also lowering both the martensite start temperature and the temperature at which austenite transforms into ferrite and cementite. During quenching, this allows a slower cooling rate, which allows items with thicker
773:
Depending on the holding temperature, austempering can produce either upper or lower bainite. Upper bainite is a laminate structure formed at temperatures typically above 350 °C (662 °F) and is a much tougher microstructure. Lower bainite is a needle-like structure, produced at temperatures
725:
Differential tempering consists of applying heat to only a portion of the blade, usually the spine, or the center of double-edged blades. For single-edged blades, the heat, often in the form of a flame or a red-hot bar, is applied to the spine of the blade only. The blade is then carefully watched as
788:
Martempering is similar to austempering, in that the steel is quenched in a bath of molten metal or salts to quickly cool it past the pearlite-forming range. However, in martempering, the goal is to create martensite rather than bainite. The steel is quenched to a much lower temperature than is used
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grains, mixed together within the microstructure. This produces steel that is much stronger than full-annealed steel, and much tougher than tempered quenched steel. However, added toughness is sometimes needed at a reduction in strength. Tempering provides a way to carefully decrease the hardness of
169:
Precise control of time and temperature during the tempering process is crucial to achieve the desired balance of physical properties. Low tempering temperatures may only relieve the internal stresses, decreasing brittleness while maintaining a majority of the hardness. Higher tempering temperatures
947:
will remain dissolved in the ferrite during tempering while the carbon precipitates. When quenched, these solutes will usually produce an increase in hardness over plain carbon steel of the same carbon content. When hardened alloy-steels, containing moderate amounts of these elements, are tempered,
836:
C). In the second stage, occurring between 150 °C (302 °F) and 300 °C (572 °F), the retained austenite transforms into a form of lower-bainite containing ε-carbon rather than cementite (archaically referred to as "troostite"). The third stage occurs at 200 °C (392 °F)
663:
For carbon steel, beyond the grey-blue color the iron oxide loses its transparency, and the temperature can no longer be judged in this way, although other alloys like stainless steel may produce a much broader range including golds, teals, and magentas. The layer will also increase in thickness as
565:
or by a quench and self-temper (QST) process. After the bar exits the final rolling pass, where the final shape of the bar is applied, the bar is then sprayed with water which quenches the outer surface of the bar. The bar speed and the amount of water are carefully controlled in order to leave the
1005:
environment, so that the decomposing carbon does not burn off. Instead, the decomposing carbon turns into a type of graphite called "temper graphite" or "flaky graphite," increasing the malleability of the metal. Tempering is usually performed at temperatures as high as 950 °C (1,740 °F)
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increase the effect dramatically. This generally occurs because the impurities are able to migrate to the grain boundaries, creating weak spots in the structure. The embrittlement can often be avoided by quickly cooling the metal after tempering. Two-step embrittlement, however, is reversible. The
992:
Malleable (porous) cast iron is manufactured by white tempering. White tempering is used to burn off excess carbon, by heating it for extended amounts of time in an oxidizing environment. The cast iron will usually be held at temperatures as high as 1,000 °C (1,830 °F) for as long as 60
616:
Pieces of through-tempered steel flatbar. The first one, on the left, is normalized steel. The second is quenched, untempered martensite. The remaining pieces have been tempered in an oven to their corresponding temperature, for an hour each. "Tempering standards" like these are sometimes used by
411:
to be useful for most applications. Tempering is a method used to decrease the hardness, thereby increasing the ductility of the quenched steel, to impart some springiness and malleability to the metal. This allows the metal to bend before breaking. Depending on how much temper is imparted to the
1043:
Although most precipitation-hardening alloys will harden at room temperature, some will only harden at elevated temperatures and, in others, the process can be sped up by aging at elevated temperatures. Aging at temperatures higher than room-temperature is called "artificial aging". Although the
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bainite-forming range. The steel is then held at the bainite-forming temperature, beyond the point where the temperature reaches an equilibrium, until the bainite fully forms. The steel is then removed from the bath and allowed to air-cool, without the formation of either pearlite or martensite.
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temperature) to both reduce the internal stresses and to decrease the brittleness around the weld. Localized tempering is often used on welds when the construction is too large, intricate, or otherwise too inconvenient to heat the entire object evenly. Tempering temperatures for this purpose are
801:
Tempering involves a three-step process in which unstable martensite decomposes into ferrite and unstable carbides, and finally into stable cementite, forming various stages of a microstructure called tempered martensite. The martensite typically consists of laths (strips) or plates, sometimes
221:
steels and cast irons, to increase ductility, machinability, and impact strength. Steel is usually tempered evenly, called "through tempering," producing a nearly uniform hardness, but it is sometimes heated unevenly, referred to as "differential tempering," producing a variation in hardness.
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However, during tempering, elements like chromium, vanadium, and molybdenum precipitate with the carbon. If the steel contains fairly low concentrations of these elements, the softening of the steel can be retarded until much higher temperatures are reached, when compared to those needed for
486:
Tempering quenched steel at very low temperatures, between 66 and 148 °C (151 and 298 °F), will usually not have much effect other than a slight relief of some of the internal stresses and a decrease in brittleness. Tempering at higher temperatures, from 148 to 205 °C (298 to
853:
Embrittlement occurs during tempering when, through a specific temperature range, the steel experiences an increase in hardness and a reduction in ductility, as opposed to the normal decrease in hardness that occurs on either side of this range. The first type is called tempered martensite
769:
and martensite. In normalizing, both upper and lower bainite are usually found mixed with pearlite. To avoid the formation of pearlite or martensite, the steel is quenched in a bath of molten metals or salts. This quickly cools the steel past the point where pearlite can form and into the
664:
time passes, which is another reason overheating and immediate cooling is used. Steel in a tempering oven, held at 205 °C (401 °F) for a long time, will begin to turn brown, purple, or blue, even though the temperature did not exceed that needed to produce a light-straw color.
873:
Two-step embrittlement typically occurs by aging the metal within a critical temperature range, or by slowly cooling it through that range, For carbon steel, this is typically between 370 °C (698 °F) and 560 °C (1,040 °F), although impurities like phosphorus and
802:
appearing acicular (needle-like) or lenticular (lens-shaped). Depending on the carbon content, it also contains a certain amount of "retained austenite." Retained austenite are crystals that are unable to transform into martensite, even after quenching below the martensite finish (M
984:, it is usually tempered to produce malleable or ductile cast iron. Two methods of tempering are used, called "white tempering" and "black tempering." The purpose of both tempering methods is to cause the cementite within the ledeburite to decompose, increasing the ductility.
242:
wrote, "There is still so much confusion between the words "temper," "tempering," and "hardening," in the writings of even eminent authorities, that it is well to keep these old definitions carefully in mind. I shall employ the word tempering in the same sense as softening."
65:
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
714:, to provide a very hard edge while softening the spine or center of the blade. This increased the toughness while maintaining a very hard, sharp, impact-resistant edge, helping to prevent breakage. This technique was more often found in Europe, as opposed to the
857:
One-step embrittlement usually occurs in carbon steel at temperatures between 230 °C (446 °F) and 290 °C (554 °F), and was historically referred to as "500 degree embrittlement." This embrittlement occurs due to the precipitation of
923:
can cause the steel to retain its hardness, even at red-hot temperatures, forming high-speed steels. Often, small amounts of many different elements are added to the steel to give the desired properties, rather than just adding one or two.
734:
Interrupted quenching methods are often referred to as tempering, although the processes are very different from traditional tempering. These methods consist of quenching to a specific temperature that is above the martensite start
960:
Cast iron comes in many types, depending on the carbon content. However, they are usually divided into grey and white cast iron, depending on the form that the carbides take. In grey cast iron, the carbon is mainly in the form of
591:
Because few methods of precisely measuring temperature existed until modern times, the temperature was usually judged by watching the tempering colors of the metal. Tempering often consisted of heating above a charcoal or coal
312:– Brittleness describes a material's tendency to break before bending or deforming either elastically or plastically. Brittleness increases with decreased toughness, but is greatly affected by internal stresses as well.
629:
will also increase. Although iron oxide is not normally transparent, such thin layers do allow light to pass through, reflecting off both the upper and lower surfaces of the layer. This causes a phenomenon called
34:
Differentially tempered steel. The various colors produced indicate the temperature the steel was heated to. Light straw indicates 204 °C (399 °F) and light blue indicates 337 °C (639 °F).
198:, tempering at low temperatures may produce an increase in hardness, while at higher temperatures the hardness will decrease. Many steels with high concentrations of these alloying elements behave like
825:, in which the transformation occurs due to shear stresses created in the crystal lattices rather than by chemical changes that occur during precipitation. The shear stresses create many defects, or "
1040:
are also precipitation-hardening alloys. These alloys become softer than normal when quenched and then harden over time. For this reason, precipitation hardening is often referred to as "aging."
332:– Also called flexibility, this is the ability to deform, bend, compress, or stretch and return to the original shape once the external stress is removed. Elasticity is inversely related to the
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alloy) the desired results, (i.e.: strengthening rather than softening), and the amount of time held at a certain temperature is very different from tempering as used in carbon-steel.
1020:
Precipitation-hardening alloys first came into use during the early 1900s. Most heat-treatable alloys fall into the category of precipitation-hardening alloys, including alloys of
455:, leaving the steel only partially softened. Tempering is sometimes used on normalized steels to further soften it, increasing the malleability and machinability for easier
540:
from the uneven heating, solidification, and cooling creates internal stresses in the metal, both within and surrounding the weld. Tempering is sometimes used in place of
536:(HAZ), consists of steel that varies considerably in hardness, from normalized steel to steel nearly as hard as quenched steel near the edge of this heat-affected zone.
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core of the bar unquenched. The hot core then tempers the already quenched outer part, leaving a bar with high strength but with a certain degree of ductility too.
588:(modern-day Turkey), in the twelfth or eleventh century BC. Without knowledge of metallurgy, tempering was originally devised through a trial-and-error method.
1044:
method is similar to tempering, the term "tempering" is usually not used to describe artificial aging, because the physical processes, (i.e.: precipitation of
739:) temperature, and then holding at that temperature for extended amounts of time. Depending on the temperature and the amount of time, this allows either pure
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for up to 20 hours. The tempering is followed by slow cooling through the lower critical temperature, over a period that may last from 50 to over 100 hours.
1476:
495:
Steel that has been heated above its upper critical temperature and then cooled in standing air is called normalized steel. Normalized steel consists of
134:
of the metal to put it in its hardest state. Tempering is accomplished by controlled heating of the quenched workpiece to a temperature below its "lower
832:
The first stage of tempering occurs between room temperature and 200 °C (392 °F). In the first stage, carbon precipitates into ε-carbon (Fe
743:
to form, or holds off forming the martensite until much of the internal stresses relax. These methods are known as austempering and martempering.
1001:
Ductile (non-porous) cast iron (often called "black iron") is produced by black tempering. Unlike white tempering, black tempering is done in an
973:, mixed with graphite and sometimes ferrite. Grey cast iron is usually used as cast, with its properties being determined by its composition.
90:
formed when steel is quenched. Tempering reduces the hardness in the martensite by transforming it into various forms of tempered martensite.
1982:
702:
Differential tempering is a method of providing different amounts of temper to different parts of the steel. The method is often used in
698:
A differentially tempered sword. The center is tempered to a springy hardness while the edges are tempered slightly harder than a hammer.
318:– The ability to mold, bend or deform in a manner that does not spontaneously return to its original shape. This is proportional to the
1404:
Steels: Microstructure and
Properties: Microstructure and Properties By Harry Bhadeshia, Robert Honeycombe -- Elsevier 2006Page 191--207
931:
Tempering methods for alloy steels may vary considerably, depending on the type and amount of elements added. In general, elements like
580:
Tempering was originally a process used and developed by blacksmiths (forgers of iron). The process was most likely developed by the
806:) temperature. An increase in alloying agents or carbon content causes an increase in retained austenite. Austenite has much higher
302:– A surface's resistance to scratching, abrasion, or indentation. In conventional metal alloys, there is a linear relation between
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embrittlement (TME) or one-step embrittlement. The second is referred to as temper embrittlement (TE) or two-step embrittlement.
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does, and carbon-steel heat-treating behavior can vary radically depending on alloying elements. Steel can be softened to a very
928:
cross-sections to be hardened to greater depths than is possible in plain carbon steel, producing more uniformity in strength.
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451:, quenched steel is almost always tempered to some degree. However, steel is sometimes annealed through a process called
1462:
887:
Many elements are often alloyed with steel. The main purpose for alloying most elements with steel is to increase its
342:– Usually synonymous with high-strength toughness, it is the ability to resist shock-loading with minimal deformation.
202:, which produces the opposite effects under the conditions found in quenching and tempering, and are referred to as
1962:
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embrittlement can be eliminated by heating the steel above 600 °C (1,112 °F) and then quickly cooling.
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162:. Heating above this temperature is avoided, so as not to destroy the very-hard, quenched microstructure, called
62:
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Except in rare cases where maximum hardness or wear resistance is needed, such as the untempered steel used for
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By George Adam
Roberts, George Krauss, Richard Kennedy, Richard L. Kennedy - ASM International 1998 Page 2
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mixed with pearlite. Ledeburite is very hard, making cast iron very brittle. If the white cast iron has a
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296:. Toughness often increases as strength decreases, because a material that bends is less likely to break.
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in the martensite, forming a microstructure called "tempered martensite". Tempering is also performed on
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By
Malcolm Blair, Thomas L. Stevens - Steel Founders' Society of America and ASM International Page 24-9
532:, is affected in a localized area by the heat from the welding process. This localized area, called the
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Tempering is an ancient heat-treating technique. The oldest known example of tempered martensite is a
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By Sir
William Chandler Roberts-Austen, Sydney W. Smith - Charles Griffin & Co. 1914 Page 155-156
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Time-temperature transformation (TTT) diagram. The red line shows the cooling curve for austempering.
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layer on its surface when heated. As the temperature of the steel is increased, the thickness of the
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Austempering is a technique used to form pure bainite, a transitional microstructure found between
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Manufacturing
Processes Reference Guide by Robert H. Todd, Dell K. Allen, and Leo Alting pg. 410
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Phase
Transformations in Steels, Volume 1: Fundamentals and Diffusion-Controlled Transformations
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and tearing. Strength, in metallurgy, is still a rather vague term, so is usually divided into
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and to decrease softening under temperature. Tool steels, for example, may have elements like
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Tempering is most often performed on steel that has been heated above its upper critical (A
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than martensite or pearlite, lowering the wear resistance and increasing the chances of
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Very few metals react to heat treatment in the same manner, or to the same extent, that
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blacksmiths for comparison, ensuring that the work is tempered to the proper color.
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416:(the steel returns to its original shape once the load is removed), or it may bend
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added to increase both toughness and strength, which is necessary for things like
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Light-straw – 205 °C (401 °F) – rock drills, reamers, metal-cutting saws
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Purple – 282 °C (540 °F) – surgical tools, punches, stone carving tools
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Brown – 260 °C (500 °F) – taps, dies, drill bits, hammers, cold chisels
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of the alloy. The reduction in hardness is usually accompanied by an increase in
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1178:"Correlation of Yield Strength and Tensile Strength with Hardness for Steels"
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heat sources may also affect the final result. The iron oxide layer, unlike
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Process of heat treating used to increase the toughness of iron-based alloys
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by Elena
Pereloma, David V Edmonds -- Woodhead Publishing 2012 Page 20--39
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generally around 205 °C (401 °F) and 343 °C (649 °F).
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steel, to relieve some of the stresses and excess hardness created in the
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By Romesh C. Sharma - New Age
International (P) Limited 2003 Page 101-110
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the alloy will usually soften somewhat proportionately to carbon steel.
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If steel has been freshly ground, sanded, or polished, it will form an
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tend to produce a greater reduction in the hardness, sacrificing some
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By Jon L. Dossett, Howard E. Boyer - ASM International 2006 Page 112
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New Edge of the Anvil: a resource book for the blacksmith. pp. 98–99
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Faint-yellow – 176 °C (349 °F) – gravers, razors, scrapers
1809:
1551:
1537:
1529:
1029:
1021:
981:
970:
962:
944:
896:
892:
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Grey-blue – 371 °C (700 °F) and higher – structural steel
656:
Light blue – 337 °C (639 °F) – springs, wood-cutting saws
585:
581:
496:
433:
403:, or it can be hardened to a state as hard and brittle as glass by
357:
353:
299:
289:
231:
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115:
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544:(even heating and cooling of the entire object to just below the A
940:
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504:
460:
361:
349:
235:
214:
131:
61:, and is done by heating the metal to some temperature below the
644:
Dark-straw – 226 °C (439 °F) – scribers, planer blades
306:
and tensile strength, which eases the measurement of the latter.
1033:
965:, but in white cast iron, the carbon is usually in the form of
936:
916:
900:
875:
757:
976:
White cast iron is composed mostly of a microstructure called
969:. Grey cast iron consists mainly of the microstructure called
653:
Dark blue – 310 °C (590 °F) – screwdrivers, wrenches
1489:
711:
707:
622:
593:
103:
99:
67:
50:
41:
is a process of heat treating, which is used to increase the
1340:
by
Leonard Ernest Samuels ASM International 1999 Page 20--25
1485:
915:
need to retain their hardness at high temperatures. Adding
673:
479:) temperature and then quickly cooled, in a process called
46:
1304:
By Flake C. Campbell - ASM International 2008 Page 195-196
348:– Usually synonymous with hardness, this is resistance to
1130:
By John D. Verhoeven - ASM International 2007 Page 99-105
142:) temperature: the temperature at which the crystalline
1375:"Hardenable Alloy Steels :: Total Materia Article"
270:(strength beyond which deformation becomes permanent),
1394:
By George E. Totten -- CRC Press 2007 Page 6, 200--203
1364:
By Flake C. Campbell - ASM International 2008 Page 197
1422:
By Miklós Tisza - ASM International 2002 Page 348-350
1263:
By Percy W. Blandford - TAB Books 1988 Page 3, 74–75
1415:
1413:
1411:
561:
of 500 MPa strength can be made from expensive
126:
of the metal. Tempering is usually performed after
1176:Pavlina, E. J.; Tyne, C. J. Van (1 December 2008).
1123:
1121:
1119:
1117:
1115:
1097:
By Thomas B. Brill - Plenum
Publishing 1980 Page 55
278:(resistance to transverse, or cutting forces), and
1316:By George E. Totten -- Marcel Dekker 1997 Page 659
1450:Webpage showing heating glow and tempering colors
1408:
1392:Steel Heat Treatment: Metallurgy and Technologies
1297:
1295:
1293:
1275:By Percy W. Blandford - TAB Books 1988 Page 74-75
1009:
676:, also protects the steel from corrosion through
1995:
1287:By Ed Fowler - Krause Publications 2003 Page 114
1182:Journal of Materials Engineering and Performance
1112:
282:(resistance to elastic shortening under a load).
213:, tempering alters the size and distribution of
1095:Light, its interaction with art and antiquities
374:, and producing a minimal amount of flexing or
1290:
70:are often tempered at low temperatures, while
1484:
1470:
1362:Elements of metallurgy and engineering alloys
1302:Elements of metallurgy and engineering alloys
1445:A thorough discussion of tempering processes
1175:
718:techniques more common in Asia, such as in
86:Photomicrograph of martensite, a very hard
1477:
1463:
74:are tempered at much higher temperatures.
1285:Knife Talk II: The High Performance Blade
1251:By Todd Bridigum - Motorbook 2008 Page 37
1201:
1142:By Michael 'Tinker' Pearce - 2007 Page 39
1128:Steel metallurgy for the non-metallurgist
683:
552:
154:, begin combining to form a single-phase
1273:Practical Blacksmithing and Metalworking
1261:Practical Blacksmithing and Metalworking
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729:
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611:
528:, or welded in any other manner besides
81:
29:
53:. Tempering is usually performed after
14:
1996:
1140:The Medieval Sword in the Modern World
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1350:Principles of Heat Treatment of Steel
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25:
2015:
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1420:Physical metallurgy for engineers
1338:Light Microscopy of Carbon Steels
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274:(the ultimate tearing strength),
190:, containing other elements like
1632:
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459:. Tempering may also be used on
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240:William Chandler Roberts-Austen
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57:, to reduce some of the excess
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1088:
1010:Precipitation hardening alloys
821:The martensite forms during a
246:
200:precipitation hardening alloys
13:
1:
1502:History of ferrous metallurgy
1314:Steel Heat Treatment Handbook
1082:
816:cold and cryogenic treatments
98:technique applied to ferrous
1745:Argon oxygen decarburization
955:
823:diffusionless transformation
7:
1906:Differential heat treatment
1072:Precipitation strengthening
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10:
2020:
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866:, or alloying agents like
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262:– Resistance to permanent
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1830:Ferritic nitrocarburizing
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1203:10.1007/s11665-008-9225-5
122:, thereby decreasing the
1921:Post weld heat treatment
982:hypoeutectic composition
1507:List of steel producers
1237:Practical heat treating
1225:Steel castings handbook
1016:Precipitation hardening
793:are often martempered.
378:, to provide a maximum
186:. However, in some low
1735:Electro-slag remelting
1106:Andrews, Jack (1994).
1062:Annealing (metallurgy)
762:
720:Japanese swordsmithing
716:differential hardening
699:
690:Differential tempering
684:Differential tempering
632:thin-film interference
618:
553:Quench and self-temper
91:
35:
2004:Metal heat treatments
1945:Production by country
907:. On the other hand,
808:stacking-fault energy
760:
730:Interrupted quenching
697:
615:
292:, as measured by the
146:of the alloy, called
110:, to achieve greater
85:
33:
1931:Superplastic forming
1850:Quench polish quench
1740:Vacuum arc remelting
1719:Basic oxygen process
1714:Electric arc furnace
818:prior to tempering.
520:Steel that has been
368:Structural integrity
304:indentation hardness
280:compressive strength
136:critical temperature
1886:Cryogenic treatment
1709:Open hearth furnace
1697:Primary (Post-1850)
1688:Cementation process
1575:Direct reduced iron
1379:www.keytometals.com
1194:2008JMEP...17..888P
538:Thermal contraction
412:steel, it may bend
234:which was found in
178:for an increase in
1657:Primary (Pre-1850)
797:Physical processes
763:
700:
619:
563:microalloyed steel
534:heat-affected zone
465:heat affected zone
409:fracture toughness
114:by decreasing the
92:
36:
1991:
1990:
1939:
1938:
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1752:
1628:
1627:
1619:Induction furnace
467:around the weld.
340:Impact resistance
326:of the substance.
130:, which is rapid
16:(Redirected from
2011:
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1704:Bessemer process
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542:stress relieving
503:, and sometimes
491:Normalized steel
442:tensile strength
336:of the material.
288:– Resistance to
272:tensile strength
176:tensile strength
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1664:Pattern welding
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1568:Anthracite iron
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1516:Iron production
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1429:Further reading
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1036:. Several high-
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997:Black tempering
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988:White tempering
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346:Wear resistance
334:Young's modulus
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204:maraging steels
158:referred to as
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94:Tempering is a
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1815:Carbonitriding
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1673:Damascus steel
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1439:External links
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1048:phases from a
1014:Main article:
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156:solid solution
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96:heat treatment
88:microstructure
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63:critical point
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1873:Martempering
1868:Austempering
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1777:Low hydrogen
1595:Finery forge
1591:Wrought iron
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387:Carbon steel
380:service life
324:malleability
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188:alloy steels
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78:Introduction
38:
37:
1916:Forming gas
1820:Carburizing
1677:Wootz steel
1643:Steelmaking
1542:sponge iron
1249:How To Weld
1152:Tool steels
678:passivation
670:carburizing
602:carburizing
453:normalizing
418:plastically
414:elastically
310:Brittleness
294:Charpy test
264:deformation
247:Terminology
124:brittleness
1973:Luxembourg
1953:Bangladesh
1895:Deflashing
1805:Ausforming
1648:Steel mill
1558:Cold blast
1550:(produces
1540:(produces
1492:production
1083:References
978:ledeburite
921:molybdenum
909:drill bits
864:phosphorus
627:iron oxide
576:Blacksmith
526:gas welded
522:arc welded
501:martensite
422:fracturing
376:deflection
330:Elasticity
316:Plasticity
253:metallurgy
219:normalized
196:molybdenum
184:plasticity
180:elasticity
164:martensite
102:, such as
1926:Quenching
1900:Hardening
1890:Deburring
1860:Tempering
1840:Nitriding
1835:Induction
1825:Cryogenic
1792:Hardening
1769:Annealing
1728:Secondary
1611:Cast iron
1584:Secondary
1563:Hot blast
1520:Ironworks
1212:135890256
1026:magnesium
1003:inert gas
967:cementite
956:Cast iron
933:manganese
868:manganese
666:Oxidizing
598:oxidizing
481:quenching
438:ductility
405:quenching
401:annealing
397:malleable
320:ductility
286:Toughness
160:austenite
152:cementite
128:quenching
120:ductility
112:toughness
108:cast iron
55:hardening
43:toughness
39:Tempering
1998:Category
1810:Boriding
1602:Puddling
1552:pig iron
1538:Bloomery
1530:Smelting
1056:See also
1030:titanium
1022:aluminum
971:pearlite
963:graphite
945:aluminum
901:wrenches
897:vanadium
893:chromium
767:pearlite
586:Anatolia
582:Hittites
497:pearlite
434:hardness
358:spalling
354:ablation
300:Hardness
290:fracture
260:Strength
232:pick axe
215:carbides
192:chromium
116:hardness
59:hardness
1978:Nigeria
1761:methods
1605:Furnace
1190:Bibcode
941:silicon
843:machine
812:galling
741:bainite
557:Modern
510:machine
505:bainite
372:fatigue
362:galling
350:erosion
236:Galilee
226:History
148:ferrite
132:cooling
72:springs
49:-based
1210:
1034:nickel
1032:, and
943:, and
937:nickel
917:cobalt
876:sulfur
712:swords
708:knives
461:welded
440:, and
144:phases
100:alloys
51:alloys
1968:Italy
1963:India
1958:China
1613:(via
1593:(via
1490:steel
1208:S2CID
791:files
623:oxide
594:forge
449:files
360:, or
104:steel
68:tools
1597:or
1488:and
1486:Iron
911:and
903:and
839:form
710:and
674:rust
194:and
182:and
174:and
150:and
47:iron
1617:or
1198:doi
919:or
895:or
841:or
834:2,4
668:or
600:or
584:of
322:or
251:In
209:In
106:or
45:of
2000::
1794:/
1675:,
1554:)
1410:^
1377:.
1292:^
1206:.
1196:.
1186:17
1184:.
1180:.
1114:^
1028:,
1024:,
939:,
935:,
845:.
735:(M
722:.
680:.
524:,
512:.
499:,
436:,
432:,
428:,
356:,
352:,
206:.
166:.
1902:)
1888:(
1679:)
1671:(
1650:)
1646:(
1621:)
1607:)
1544:)
1522:)
1518:(
1478:e
1471:t
1464:v
1381:.
1214:.
1200::
1192::
804:f
737:s
546:1
477:3
382:.
364:.
140:1
20:)
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