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Steel is an
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
made up of
iron Iron () is a with Fe (from la, ) and 26. It is a that belongs to the and of the . It is, on , right in front of (32.1% and 30.1%, respectively), forming much of Earth's and . It is the fourth most common . In its metallic state, iron ...

iron
with typically a few tenths of a percent of
carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three occur naturally, ...

carbon
to improve its
strength Physical strength *Physical strength, as in people or animals *Hysterical strength, extreme strength occurring when people are in life-and-death situations *Superhuman strength, great physical strength far above human capability *A common attrib ...
and
fracture resistance
fracture resistance
compared to other forms of iron. Many other elements may be present or added. Stainless steels that are
corrosion Corrosion is a that converts a refined metal into a more chemically stable form such as , , or . It is the gradual destruction of materials (usually a ) by chemical and/or electrochemical reaction with their environment. is the field dedica ...

corrosion
- and oxidation-resistant need typically an additional 11%
chromium Chromium is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science tha ...

chromium
. Because of its high
tensile strength In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through Spa ...
and low cost, steel is used in
building A building, or edifice, is a structure with a roof and walls standing more or less permanently in one place, such as a house A house is a single-unit residential building, which may range in complexity from a rudimentary hut to a complex st ...

building
s,
infrastructure Infrastructure is the set of fundamental facilities and systems that support the sustainable functionality of households and firms. Serving a country, city, or other area, including the services and facilities necessary for its economy An eco ...

infrastructure
,
tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment. Although many animals use simple tools, only human beings, whose use of stone tool A stone tool is, in the most general sense, a ...

tool
s,
ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep Sea lane, waterways, carrying goods or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally disti ...

ship
s,
train In rail transport Rail transport (also known as train transport) is a means of transferring passengers and goods on wheeled vehicles running on rails, which are located on tracks. In contrast to road transport, where the vehicles run ...

train
s,
car A car (or automobile) is a wheeled motor vehicle Electric bicycles parked in Yangzhou's main street, Wenchang Lu. They are a very common way of transport in this city, in some areas almost outnumbering regular bicycles A motor vehicle, also k ...

car
s,
machine A machine is any physical system with ordered structural and functional properties. It may represent human-made or naturally occurring device molecular machine A molecular machine, nanite, or nanomachine is a molecular component that produce ...

machine
s, electrical appliances, and
weapon A weapon, arm or armament is any implement or device that can be used with the intent to inflict physical damage or harm. Weapons are used to increase the efficacy and efficiency of activities such as hunting Hunting is the practice of see ...
s. Iron is the
base metal A base metal is a common and inexpensive metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conduc ...
of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body centred cubic and face centred cubic. The interaction of the
allotropes of iron At atmospheric pressure Atmospheric pressure, also known as barometric pressure (after the barometer A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short ...
with the alloying elements, primarily carbon, gives steel and
cast iron Cast iron is a group of iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of ...
their range of unique properties. In pure iron, the
crystal structure In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "col ...
has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite
ductile Ductility is a mechanical property commonly described as a material's amenability to drawing Drawing is a form of visual art in which an artist uses instruments to mark paper Paper is a thin sheet material produced by mechanically a ...

ductile
, or soft and easily formed. In steel, small amounts of carbon, other elements, and inclusions within the iron act as hardening agents that prevent the movement of
dislocation In materials science The Interdisciplinarity, interdisciplinary field of materials science, also commonly termed materials science and engineering, covers the design and discovery of new materials, particularly solids. The intellectual origins o ...

dislocation
s. The carbon in typical steel alloys may contribute up to 2.14% of its weight. Varying the amount of carbon and many other alloying elements, as well as controlling their chemical and physical makeup in the final steel (either as solute elements, or as precipitated phases), slows the movement of those dislocations that make pure iron ductile, and thus controls and enhances its qualities. These qualities include the
hardness Hardness (antonym: softness) is a measure of the resistance to localized induced by either mechanical or . In general, different materials differ in their hardness; for example hard metals such as and are harder than soft metals such as and ...
,
quenching behaviour
quenching behaviour
, need for annealing, tempering behaviour,
yield strength In materials science The Interdisciplinarity, interdisciplinary field of materials science, also commonly termed materials science and engineering, covers the design and discovery of new materials, particularly solids. The intellectual origi ...
, and
tensile strength In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through Spa ...
of the resulting steel. The increase in steel's strength compared to pure iron is possible only by reducing iron's ductility. Steel was produced in
bloomery A bloomery is a type of furnace A furnace, referred to as a heater or boiler in British English, is a heating unit used to heat up an entire building. Furnaces are mostly used as a major component of a central heating system. The name de ...
furnaces for thousands of years, but its large-scale, industrial use began only after more efficient production methods were devised in the 17th century, with the introduction of the
blast furnace A blast furnace is a type of used for to produce industrial metals, generally , but also others such as or . ''Blast'' refers to the combustion air being "forced" or supplied above atmospheric pressure. In a blast furnace, fuel (), , and ( ...
and production of
crucible steel Crucible steel is steel Steel is an alloy of iron with typically a few tenths of a percent of carbon to improve its strength of materials, strength and fracture toughness, fracture resistance compared to iron. Many other elements may be pre ...
. This was followed by the
open-hearth furnace Open-hearth furnaces are one of several kinds of furnace in which excess carbon Carbon (from la, carbo "coal") is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemica ...
and then the
Bessemer process The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is steelmaking, removal of impurities from the iron by oxi ...

Bessemer process
in
England England is a that is part of the . It shares land borders with to its west and to its north. The lies northwest of England and the to the southwest. England is separated from by the to the east and the to the south. The country cover ...

England
in the mid-19th century. With the invention of the Bessemer process, a new era of
mass-produced Mass production, also known as flow production or continuous production, is the production of substantial amounts of standardized Standardization or standardisation is the process of implementing and developing technical standard A technic ...
steel began.
Mild steel Carbon steel is a steel Steel is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fract ...
replaced
wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag Inclusion (mineral), inclusions (up to 2% by weight), which gives it a ...
.
The German states This list of states which were part of the Holy Roman Empire includes any territory ruled by an authority that had been granted imperial immediacy, as well as many other feudal entities such as lordships, sous-fiefs and allodial fiefs. The Holy ...
saw major steel prowess over Europe in the 19th century. Further refinements in the process, such as
basic oxygen steelmaking Basic oxygen steelmaking (BOS, BOP, BOF, or OSM), also known as Linz-Donawitz steelmaking or the oxygen converter processBrock and Elzinga, p. 50. is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing o ...
(BOS), largely replaced earlier methods by further lowering the cost of production and increasing the quality of the final product. Today, steel is one of the most common man made materials in the world, with more than 1.6 billion tons produced annually. Modern steel is generally identified by various grades defined by assorted standards organisations.


Definitions and related materials

The noun ''steel'' originates from the
Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed Reconstruction may refer to: Politics, history, and sociology *Reconstruction (law), the transfer of a company's (or several companies') business to a new ...
adjective ''stahliją'' or ''stakhlijan'' 'made of steel', which is related to ''stahlaz'' or ''stahliją'' 'standing firm'. The carbon content of steel is between 0.002% and 2.14% by weight for plain carbon steel (
iron Iron () is a with Fe (from la, ) and 26. It is a that belongs to the and of the . It is, on , right in front of (32.1% and 30.1%, respectively), forming much of Earth's and . It is the fourth most common . In its metallic state, iron ...

iron
-
carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three occur naturally, ...

carbon
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
s). Too little carbon content leaves (pure) iron quite soft, ductile, and weak. Carbon contents higher than those of steel make a brittle alloy commonly called
pig iron Pig iron, also known as crude iron, is an intermediate product Intermediate goods, producer goods or semi-finished products are goods In economics Economics () is the social science that studies how people interact with value; in parti ...

pig iron
.
Alloy steel Alloy steel is steel Steel is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, s ...
is steel to which other alloying elements have been intentionally added to modify the characteristics of steel. Common alloying elements include:
manganese Manganese is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science ...

manganese
,
nickel Nickel is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same nu ...

nickel
,
chromium Chromium is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science tha ...

chromium
,
molybdenum Molybdenum is a with the Mo and 42. The name is from ''molybdaenum'', which is based on ', meaning , since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the ...

molybdenum
,
boron Boron is a chemical element with the Symbol (chemistry), symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar System a ...

boron
,
titanium Titanium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical ele ...

titanium
,
vanadium Vanadium is a chemical element with the Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...

vanadium
,
tungsten Tungsten, or wolfram, is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have ...

tungsten
,
cobalt Cobalt is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that c ...

cobalt
, and
niobium Niobium, also known as columbium, is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. I ...

niobium
. Additional elements, most frequently considered undesirable, are also important in steel:
phosphorus Phosphorus is a chemical element with the Symbol (chemistry), symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly Reactivity (chemistry), reactive, phosphor ...

phosphorus
,
sulfur Sulfur (in nontechnical British English: sulphur) is a with the  S and  16. It is , and lic. Under , sulfur atoms form cyclic octatomic molecules with a chemical formula . Elemental sulfur is a bright yellow, line solid at . Sul ...

sulfur
,
silicon Silicon is a chemical element with the Symbol (chemistry), symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a Tetravalence, tetravalent metalloid and semiconductor. It is a member ...

silicon
, and traces of
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
,
nitrogen Nitrogen is the chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science ...

nitrogen
, and
copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal and electrical conductivity. A fre ...

copper
. Plain carbon-iron alloys with a higher than 2.1% carbon content are known as
cast iron Cast iron is a group of iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of ...
. With modern
steelmaking Steelmaking is the process of producing steel Steel is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared ...
techniques such as powder metal forming, it is possible to make very high-carbon (and other alloy material) steels, but such are not common. Cast iron is not malleable even when hot, but it can be formed by
casting Casting is a manufacturing Manufacturing is the creation or Production (economics), production of goods with the help of equipment, Work (human activity), labor, machines, tools, and chemical or biological processing or formulation. It is th ...

casting
as it has a lower
melting point The melting point (or, rarely, liquefaction point) of a substance is the at which it changes from to . At the melting point the solid and liquid phase exist in . The melting point of a substance depends on and is usually specified at a such ...

melting point
than steel and good
castabilityCastability is the ease of forming a quality casting. A very castable part design is easily developed, incurs minimal tooling costs, requires minimal energy, and has few rejections.Ravi, p. 2 Castability can refer to a part design or a material pr ...
properties. Certain compositions of cast iron, while retaining the economies of melting and casting, can be heat treated after casting to make
malleable iron Malleable iron is cast as white iron, the structure being a metastable carbide in a pearlitic matrix. Through an Annealing (metallurgy), annealing heat treatment, the brittle structure as first cast is transformed into the malleable form. Carbon a ...
or
ductile iron Ductility is a mechanical property commonly described as a material's amenability to drawing Drawing is a form of visual art in which an artist uses instruments to mark paper Paper is a thin sheet material produced by mechanically and ...

ductile iron
objects. Steel is distinguishable from
wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag Inclusion (mineral), inclusions (up to 2% by weight), which gives it a ...
(now largely obsolete), which may contain a small amount of carbon but large amounts of
slag Slag is a by-product of smelting Smelting is a process of applying heat to ore ore – psilomelane (size: 6.7 × 5.8 × 5.1 cm) ore – galena and anglesite (size: 4.8 × 4.0 × 3.0 cm) ore (size: 7.5 × 6.1 × 4.1 cm) File: ...

slag
.


Material properties


Origins and production

Iron is commonly found in the Earth's crust in the form of an
ore ore – psilomelane Psilomelane is a group name for hard black manganese oxides including hollandite and romanechite. Psilomelane consists of hydrous manganese Manganese is a chemical element Image:Simple Periodic Table Chart- ...

ore
, usually an iron oxide, such as
magnetite Magnetite is a mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rocks of which it i ...

magnetite
or
hematite Hematite (), also spelled as haematite, is a common iron oxide Iron oxides are chemical compounds composed of iron and oxygen Oxygen is the chemical element with the chemical symbol, symbol O and atomic number 8. It is a member o ...

hematite
. Iron is extracted from
iron ore Iron ores are rocks A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition and the way in which it is formed. Rock ...
by removing the oxygen through its combination with a preferred chemical partner such as carbon which is then lost to the atmosphere as carbon dioxide. This process, known as
smelting Smelting is a process of applying heat to ore ore – psilomelane (size: 6.7 × 5.8 × 5.1 cm) ore – galena and anglesite (size: 4.8 × 4.0 × 3.0 cm) ore (size: 7.5 × 6.1 × 4.1 cm) File:OreCartPachuca.JPG, upMinecart on ...
, was first applied to metals with lower
melting Melting, or Enthalpy of fusion, fusion, is a physical process that results in the phase transition of a chemical substance, substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the applic ...

melting
points, such as
tin Tin is a with the Sn (from la, ) and  50. Tin is a silvery-colored metal that characteristically has a faint yellow hue. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent ...

tin
, which melts at about , and
copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal and electrical conductivity. A fre ...

copper
, which melts at about , and the combination, bronze, which has a melting point lower than . In comparison, cast iron melts at about . Small quantities of iron were smelted in ancient times, in the solid-state, by heating the ore in a
charcoal or soil, and firing it (circa 1890) Charcoal is a lightweight black carbon Carbon (from la, carbo "coal") is a chemical element with the Symbol (chemistry), symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent ...

charcoal
fire and then
welding Welding is a process that joins materials, usually s or s, by using high to melt the parts together and allowing them to cool, causing . Welding is distinct from lower temperature metal-joining techniques such as and , which do not the base ...

welding
the clumps together with a hammer and in the process squeezing out the impurities. With care, the carbon content could be controlled by moving it around in the fire. Unlike copper and tin, liquid or solid iron dissolves carbon quite readily. All of these temperatures could be reached with ancient methods used since the
Bronze Age The Bronze Age is a prehistoric that was characterized by the use of , in some areas , and other early features of urban . The Bronze Age is the second principal period of the , as proposed in modern times by , for classifying and studying a ...
. Since the oxidation rate of iron increases rapidly beyond , it is important that smelting take place in a low-oxygen environment. Smelting, using carbon to reduce iron oxides, results in an alloy (
pig iron Pig iron, also known as crude iron, is an intermediate product Intermediate goods, producer goods or semi-finished products are goods In economics Economics () is the social science that studies how people interact with value; in parti ...

pig iron
) that retains too much carbon to be called steel. The excess carbon and other impurities are removed in a subsequent step. Other materials are often added to the iron/carbon mixture to produce steel with the desired properties.
Nickel Nickel is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same nu ...

Nickel
and
manganese Manganese is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science ...

manganese
in steel add to its tensile strength and make the
austenite 250px, Iron-carbon phase diagram, showing the conditions under which austenite (γ) is stable in carbon steel. Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron I ...
form of the iron-carbon solution more stable,
chromium Chromium is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science tha ...

chromium
increases hardness and melting temperature, and
vanadium Vanadium is a chemical element with the Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...

vanadium
also increases hardness while making it less prone to
metal fatigue In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striation (fatigue), striatio ...
. To inhibit corrosion, at least 11% chromium can be added to steel so that a hard
oxide An oxide () is a chemical compound A chemical compound is a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having vol ...
forms on the metal surface; this is known as
stainless steel Stainless steel is a group of that contain a minimum of approximately 11% , a composition that prevents the from ing and also provides heat-resistant properties.“Corrosion: Chemical process". ''Encyclopædia Britannica'', Chicago, IL: Encyc ...
. Tungsten slows the formation of
cementite Cementite (or iron carbide) is a Chemical compound, compound of iron and carbon, more precisely an intermediate transition metal carbide with the formula Fe3C. By weight, it is 6.67% carbon and 93.3% iron. It has an orthorhombic crystal structure. I ...

cementite
, keeping carbon in the iron matrix and allowing
martensite 200px, 0.35% carbon steel, water-quenched from 870 °C Martensite is a very hard form of steel Steel is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, ...

martensite
to preferentially form at slower quench rates, resulting in
high-speed steel High-speed steel (HSS or HS) is a subset of tool steel Tool steel is any of various carbon steel Carbon steel is a steel with carbon content from about 0.05 up to 3.8 per cent by weight. The definition of carbon steel from the American Iron ...
. The addition of
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
and
sulfur Sulfur (in nontechnical British English: sulphur) is a with the  S and  16. It is , and lic. Under , sulfur atoms form cyclic octatomic molecules with a chemical formula . Elemental sulfur is a bright yellow, line solid at . Sul ...

sulfur
decrease grain size, thereby making the steel easier to
turn Turn may refer to: Arts and entertainment Dance and sports * Turn (dance and gymnastics), rotation of the body * Turn (swimming), reversing direction at the end of a pool * Turn (professional wrestling), a transition between face and heel * Turn, ...

turn
, but also more brittle and prone to corrosion. Such alloys are nevertheless frequently used for components such as nuts, bolts, and washers in applications where toughness and corrosion resistance are not paramount. For the most part, however,
p-block A block of the periodic table is a set of elements unified by the orbitals their valence electrons or vacancies lie in. The term appears to have been first used by Charles Janet. Each block is named after its characteristic orbital: s-block, p-blo ...
elements such as sulfur,
nitrogen Nitrogen is the chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science ...

nitrogen
,
phosphorus Phosphorus is a chemical element with the Symbol (chemistry), symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly Reactivity (chemistry), reactive, phosphor ...

phosphorus
, and lead are considered contaminants that make steel more brittle and are therefore removed from the steel melt during processing.


Properties

The
density The density (more precisely, the volumetric mass density; also known as specific mass), of a substance is its per unit . The symbol most often used for density is ''ρ'' (the lower case Greek letter ), although the Latin letter ''D'' can also ...

density
of steel varies based on the alloying constituents but usually ranges between , or . Even in a narrow range of concentrations of mixtures of carbon and iron that make steel, several different metallurgical structures, with very different properties can form. Understanding such properties is essential to making quality steel. At
room temperature Colloquially, room temperature is the range of air temperature Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat ...
, the most stable form of pure iron is the
body-centred cubic File:Kubisches_Kristallsystem.jpg, 200px, A network model of a primitive cubic system In crystallography, the cubic (or isometric) crystal system is a crystal system where the Crystal_structure#Unit_cell, unit cell is in the shape of a cube. This ...
(BCC) structure called alpha iron or α-iron. It is a fairly soft metal that can dissolve only a small concentration of carbon, no more than 0.005% at and 0.021 wt% at . The inclusion of carbon in alpha iron is called ferrite. At 910 °C, pure iron transforms into a
face-centred cubic File:Kubisches_Kristallsystem.jpg, 200px, A network model of a primitive cubic system In crystallography, the cubic (or isometric) crystal system is a crystal system where the Crystal_structure#Unit_cell, unit cell is in the shape of a cube. This i ...
(FCC) structure, called gamma iron or γ-iron. The inclusion of carbon in gamma iron is called austenite. The more open FCC structure of austenite can dissolve considerably more carbon, as much as 2.1% (38 times that of ferrite) carbon at , which reflects the upper carbon content of steel, beyond which is cast iron. When carbon moves out of solution with iron, it forms a very hard, but brittle material called cementite (Fe3C). When steels with exactly 0.8% carbon (known as a eutectoid steel), are cooled, the
austenitic 250px, Iron-carbon phase diagram, showing the conditions under which austenite (γ) is stable in carbon steel. Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron I ...
phase (FCC) of the mixture attempts to revert to the ferrite phase (BCC). The carbon no longer fits within the FCC austenite structure, resulting in an excess of carbon. One way for carbon to leave the austenite is for it to
precipitate Precipitation is the process of conversion of a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All ever ...
out of solution as
cementite Cementite (or iron carbide) is a Chemical compound, compound of iron and carbon, more precisely an intermediate transition metal carbide with the formula Fe3C. By weight, it is 6.67% carbon and 93.3% iron. It has an orthorhombic crystal structure. I ...

cementite
, leaving behind a surrounding phase of BCC iron called ferrite with a small percentage of carbon in solution. The two, ferrite and cementite, precipitate simultaneously producing a layered structure called
pearlite Pearlite is a , (or layered) structure composed of alternating layers of (87.5 wt%) and (12.5 wt%) that occurs in some s and s. During slow cooling of an iron-carbon alloy, pearlite forms by a reaction as cools below (the eutectoid te ...

pearlite
, named for its resemblance to
mother of pearl Nacre ( also ), also known as mother of pearl, is an organicinorganic composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material Material is a substanc ...

mother of pearl
. In a hypereutectoid composition (greater than 0.8% carbon), the carbon will first precipitate out as large inclusions of cementite at the austenite
grain boundaries of a polycrystalline A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, for ...
until the percentage of carbon in the
grains A grain is a small, hard, dry – with or without an attached or layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are s and . After being harvested, dry ...
has decreased to the eutectoid composition (0.8% carbon), at which point the pearlite structure forms. For steels that have less than 0.8% carbon (hypoeutectoid), ferrite will first form within the grains until the remaining composition rises to 0.8% of carbon, at which point the pearlite structure will form. No large inclusions of cementite will form at the boundaries in hypoeuctoid steel. The above assumes that the cooling process is very slow, allowing enough time for the carbon to migrate. As the rate of cooling is increased the carbon will have less time to migrate to form carbide at the grain boundaries but will have increasingly large amounts of pearlite of a finer and finer structure within the grains; hence the carbide is more widely dispersed and acts to prevent slip of defects within those grains, resulting in hardening of the steel. At the very high cooling rates produced by quenching, the carbon has no time to migrate but is locked within the face-centred austenite and forms
martensite 200px, 0.35% carbon steel, water-quenched from 870 °C Martensite is a very hard form of steel Steel is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, ...

martensite
. Martensite is a highly strained and stressed, supersaturated form of carbon and iron and is exceedingly hard but brittle. Depending on the carbon content, the martensitic phase takes different forms. Below 0.2% carbon, it takes on a ferrite BCC crystal form, but at higher carbon content it takes a body-centred tetragonal (BCT) structure. There is no thermal activation energy for the transformation from austenite to martensite. Moreover, there is no compositional change so the atoms generally retain their same neighbors.. Martensite has a lower density (it expands during the cooling) than does austenite, so that the transformation between them results in a change of volume. In this case, expansion occurs. Internal stresses from this expansion generally take the form of physical compression, compression on the crystals of martensite and tension (mechanics), tension on the remaining ferrite, with a fair amount of shear stress, shear on both constituents. If quenching is done improperly, the internal stresses can cause a part to shatter as it cools. At the very least, they cause internal work hardening and other microscopic imperfections. It is common for quench cracks to form when steel is water quenched, although they may not always be visible.


Heat treatment

There are many types of heat treatment, heat treating processes available to steel. The most common are annealing (metallurgy), annealing, quenching, and tempering (metallurgy), tempering. Heat treatment is effective on compositions above the eutectoid composition (hypereutectoid) of 0.8% carbon. Hypoeutectoid steel does not benefit from heat treatment. Annealing is the process of heating the steel to a sufficiently high temperature to relieve local internal stresses. It does not create a general softening of the product but only locally relieves strains and stresses locked up within the material. Annealing goes through three phases: recovery (metallurgy), recovery, recrystallization (metallurgy), recrystallization, and grain growth. The temperature required to anneal a particular steel depends on the type of annealing to be achieved and the alloying constituents. Quenching involves heating the steel to create the austenite phase then quenching it in water or oil. This rapid cooling results in a hard but brittle martensitic structure. The steel is then tempered, which is just a specialized type of annealing, to reduce brittleness. In this application the annealing (tempering) process transforms some of the martensite into cementite, or spheroidite and hence it reduces the internal stresses and defects. The result is a more ductile and fracture-resistant steel.


Steel production

When iron is smelting, smelted from its ore, it contains more carbon than is desirable. To become steel, it must be reprocessed to reduce the carbon to the correct amount, at which point other elements can be added. In the past, steel facilities would casting (metalworking), cast the raw steel product into ingots which would be stored until use in further refinement processes that resulted in the finished product. In modern facilities, the initial product is close to the final composition and is continuous casting, continuously cast into long slabs, cut and shaped into bars and extrusions and heat treated to produce a final product. Today, approximately 96% of steel is continuously cast, while only 4% is produced as ingots. The ingots are then heated in a soaking pit and hot rolling, hot rolled into slabs, Billet (semi-finished product)#Billet, billets, or Billet (semi-finished product)#Bloom, blooms. Slabs are hot or cold rolling, cold rolled into sheet metal or plates. Billets are hot or cold rolled into bars, rods, and wire. Blooms are hot or cold rolled into structural steel, such as I-beams and rail tracks, rails. In modern steel mills these processes often occur in one assembly line, with ore coming in and finished steel products coming out. Sometimes after a steel's final rolling, it is heat treated for strength; however, this is relatively rare.


History of steelmaking


Ancient steel

Steel was known in antiquity and was produced in Bloomery, bloomeries and crucibles.Davidson, Hilda Ellis (1998). ''The Sword in Anglo-Saxon England: Its Archaeology and Literature''. Boydell & Brewer Ltd. p. 20. . The earliest known production of steel is seen in pieces of ironware excavated from an archaeological site in Anatolia (Kaman-Kalehöyük) and are nearly 4,000 years old, dating from 1800 BC. Horace identifies steel weapons such as the ''falcata'' in the Iberian Peninsula, while Noric steel was used by the Military of ancient Rome, Roman military. The reputation of ''Seric iron'' of South India (wootz steel) grew considerably in the rest of the world. Metal production sites in Sri Lanka employed wind furnaces driven by the monsoon winds, capable of producing high-carbon steel. Large-scale Wootz steel production in India using crucibles occurred by the sixth century BC, the pioneering precursor to modern steel production and metallurgy. The History of China#Ancient China, Chinese of the Warring States period (403–221 BC) had quench, quench-hardened steel, while Chinese of the Han dynasty (202 BC – AD 220) created steel by melting together wrought iron with cast iron, thus producing a carbon-intermediate steel by the 1st century AD.Gernet, Jacques (1982). ''A History of Chinese Civilization''. Cambridge: Cambridge University Press. p. 69. . There is evidence that carbon steel was made in Western Tanzania by the ancestors of the Haya people as early as 2,000 years ago by a complex process of "pre-heating" allowing temperatures inside a furnace to reach 1300 to 1400 °C.


Wootz steel and Damascus steel

Evidence of the earliest production of high carbon steel in India are found in Kodumanal in Tamil Nadu, the Golconda area in Andhra Pradesh and Karnataka, and in the Samanalawewa areas of Sri Lanka. This came to be known as Wootz steel, produced in South India by about the sixth century BC and exported globally. The steel technology existed prior to 326 BC in the region as they are mentioned in literature of Sangam literature, Sangam Tamil, Arabic, and Latin as the finest steel in the world exported to the Romans, Egyptian, Chinese and Arab worlds at that time – what they called ''Seric Iron''. A Tissamaharama Tamil Brahmi inscription, 200 BC Tamil trade guild in Tissamaharama, in the South East of Sri Lanka, brought with them some of the oldest iron and steel artifacts and production processes to the island from the classical antiquity, classical period. The Chinese and locals in Anuradhapura, Sri Lanka had also adopted the production methods of creating Wootz steel from the Chera Dynasty Tamils of South India by the 5th century AD. In Sri Lanka, this early steel-making method employed a unique wind furnace, driven by the monsoon winds, capable of producing high-carbon steel.Coghlan, Herbert Henery. (1977). ''Notes on prehistoric and early iron in the Old World''. Oxprint. pp. 99–100 Since the technology was acquired from the Tamilians from South India, the origin of steel technology in India can be conservatively estimated at 400–500 BC. The manufacture of what came to be called Wootz, or Damascus steel, famous for its durability and ability to hold an edge, may have been taken by the Arabs from Persia, who took it from India. It was originally created from several different materials including various trace elements, apparently ultimately from the writings of Zosimos of Panopolis. In 327 BC, Alexander the Great was rewarded by the defeated King Porus, not with gold or silver but with 30 pounds of steel. Recent studies have suggested that carbon nanotubes were included in its structure, which might explain some of its legendary qualities, though, given the technology of that time, such qualities were produced by chance rather than by design. Natural wind was used where the soil containing iron was heated by the use of wood. The ancient Sinhalese managed to extract a ton of steel for every 2 tons of soil, a remarkable feat at the time. One such furnace was found in Samanalawewa and archaeologists were able to produce steel as the ancients did. Crucible steel, formed by slowly heating and cooling pure iron and carbon (typically in the form of charcoal) in a crucible, was produced in Merv by the 9th to 10th century AD. In the 11th century, there is evidence of the production of steel in Song dynasty, Song China using two techniques: a "berganesque" method that produced inferior, inhomogeneous steel, and a precursor to the modern
Bessemer process The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is steelmaking, removal of impurities from the iron by oxi ...

Bessemer process
that used partial decarbonization via repeated forging under a cold blast.


Modern steelmaking

Since the 17th century, the first step in European steel production has been the smelting of iron ore into
pig iron Pig iron, also known as crude iron, is an intermediate product Intermediate goods, producer goods or semi-finished products are goods In economics Economics () is the social science that studies how people interact with value; in parti ...

pig iron
in a
blast furnace A blast furnace is a type of used for to produce industrial metals, generally , but also others such as or . ''Blast'' refers to the combustion air being "forced" or supplied above atmospheric pressure. In a blast furnace, fuel (), , and ( ...
.Tylecote, R.F. (1992) ''A history of metallurgy'' 2nd ed., Institute of Materials, London. pp. 95–99 and 102–105. . Originally employing charcoal, modern methods use coke (fuel), coke, which has proven more economical.


Processes starting from bar iron

In these processes pig iron was refined (fined) in a finery forge to produce bar iron, which was then used in steel-making. The production of steel by the cementation process was described in a treatise published in Prague in 1574 and was in use in Nuremberg from 1601. A similar process for case hardening armor and files was described in a book published in Naples in 1589. The process was introduced to England in about 1614 and used to produce such steel by Sir Basil Brooke (metallurgist), Basil Brooke at Coalbrookdale during the 1610s. The raw material for this process were bars of iron. During the 17th century, it was realized that the best steel came from oregrounds iron of a region north of Stockholm, Sweden. This was still the usual raw material source in the 19th century, almost as long as the process was used. Crucible steel is steel that has been melted in a crucible rather than having been forging, forged, with the result that it is more homogeneous. Most previous furnaces could not reach high enough temperatures to melt the steel. The early modern crucible steel industry resulted from the invention of Benjamin Huntsman in the 1740s. Blister steel (made as above) was melted in a crucible or in a furnace, and cast (usually) into ingots.


Processes starting from pig iron

The modern era in
steelmaking Steelmaking is the process of producing steel Steel is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared ...
began with the introduction of Henry Bessemer's Bessemer process, process in 1855, the raw material for which was pig iron. His method let him produce steel in large quantities cheaply, thus mild steel came to be used for most purposes for which wrought iron was formerly used. The Gilchrist-Thomas process (or ''basic Bessemer process'') was an improvement to the Bessemer process, made by lining the converter with a basic (chemistry), basic material to remove phosphorus. Another 19th-century steelmaking process was the Siemens-Martin process, which complemented the Bessemer process. It consisted of co-melting bar iron (or steel scrap) with pig iron. These methods of steel production were rendered obsolete by the Linz-Donawitz process of
basic oxygen steelmaking Basic oxygen steelmaking (BOS, BOP, BOF, or OSM), also known as Linz-Donawitz steelmaking or the oxygen converter processBrock and Elzinga, p. 50. is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing o ...
(BOS), developed in 1952, and other oxygen steel making methods. Basic oxygen steelmaking is superior to previous steelmaking methods because the oxygen pumped into the furnace limited impurities, primarily nitrogen, that previously had entered from the air used, and because, with respect to the open hearth process, the same quantity of steel from a BOS process is manufactured in one-twelfth the time. Today, electric arc furnaces (EAF) are a common method of reprocessing scrap, scrap metal to create new steel. They can also be used for converting pig iron to steel, but they use a lot of electrical energy (about 440 kWh per metric ton), and are thus generally only economical when there is a plentiful supply of cheap electricity.


Steel industry

The steel industry is often considered an indicator of economic progress, because of the critical role played by steel in infrastructural and overall economic development. In 1980, there were more than 500,000 U.S. steelworkers. By 2000, the number of steelworkers had fallen to 224,000. The boom and bust, economic boom in China and India caused a massive increase in the demand for steel. Between 2000 and 2005, world steel demand increased by 6%. Since 2000, several Indian and Chinese steel firms have risen to prominence, such as Tata Steel (which bought Corus Group in 2007), Baosteel Group and Shagang Group. , though, ArcelorMittal is the world's List of steel producers, largest steel producer. In 2005, the British Geological Survey stated China was the top steel producer with about one-third of the world share; Japan, Russia, and the US followed respectively. The large production capacity of steel results also in a significant amount of carbon dioxide emissions inherent related to the main production route. In 2019, it was estimated that 7 to 9 % of the global carbon dioxide emissions resulted from the steel industry. Reduction of these emissions are expected to come from a shift in the main production route using cokes, more recycling of steel and the application of carbon capture and storage or carbon capture and utilization technology. In 2008, steel began commodity market, trading as a commodity on the London Metal Exchange. At the end of 2008, the steel industry faced a sharp downturn that led to many cut-backs.


Recycling

Steel is one of the world's most-recycled materials, with a recycling rate of over 60% globally; in the United States alone, over were recycled in the year 2008, for an overall recycling rate of 83%. As more steel is produced than is scrapped, the amount of recycled raw materials is about 40% of the total of steel produced - in 2016, of crude steel was produced globally, with recycled.


Contemporary steel


Carbon steels

Modern steels are made with varying combinations of alloy metals to fulfill many purposes. Carbon steel, composed simply of iron and carbon, accounts for 90% of steel production. Low alloy steel is alloyed with other elements, usually
molybdenum Molybdenum is a with the Mo and 42. The name is from ''molybdaenum'', which is based on ', meaning , since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the ...

molybdenum
, manganese, chromium, or nickel, in amounts of up to 10% by weight to improve the hardenability of thick sections. HSLA steel, High strength low alloy steel has small additions (usually < 2% by weight) of other elements, typically 1.5% manganese, to provide additional strength for a modest price increase. Recent Corporate Average Fuel Economy (CAFE) regulations have given rise to a new variety of steel known as Advanced High Strength Steel (AHSS). This material is both strong and ductile so that vehicle structures can maintain their current safety levels while using less material. There are several commercially available grades of AHSS, such as dual-phase steel, which is heat treated to contain both a ferritic and martensitic microstructure to produce a formable, high strength steel. Transformation Induced Plasticity (TRIP) steel involves special alloying and heat treatments to stabilize amounts of
austenite 250px, Iron-carbon phase diagram, showing the conditions under which austenite (γ) is stable in carbon steel. Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron I ...
at room temperature in normally austenite-free low-alloy ferritic steels. By applying strain, the austenite undergoes a phase transition to martensite without the addition of heat. Twinning Induced Plasticity (TWIP) steel uses a specific type of strain to increase the effectiveness of work hardening on the alloy. Carbon Steels are often hot-dip galvanizing, galvanized, through hot-dip or electroplating in zinc for protection against rust.


Alloy steels

Stainless steels contain a minimum of 11% chromium, often combined with nickel, to resist
corrosion Corrosion is a that converts a refined metal into a more chemically stable form such as , , or . It is the gradual destruction of materials (usually a ) by chemical and/or electrochemical reaction with their environment. is the field dedica ...

corrosion
. Some stainless steels, such as the Allotropes of iron, ferritic stainless steels are magnetic, while others, such as the austenite, austenitic, are nonmagnetic. Corrosion-resistant steels are abbreviated as CRES. Alloy steels are plain-carbon steels in which small amounts of alloying elements like chromium and vanadium have been added. Some more modern steels include tool steels, which are alloyed with large amounts of tungsten and
cobalt Cobalt is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that c ...

cobalt
or other elements to maximize solution hardening. This also allows the use of precipitation hardening and improves the alloy's temperature resistance. Tool steel is generally used in axes, drills, and other devices that need a sharp, long-lasting cutting edge. Other special-purpose alloys include weathering steels such as Cor-ten, which weather by acquiring a stable, rusted surface, and so can be used un-painted. Maraging steel is alloyed with nickel and other elements, but unlike most steel contains little carbon (0.01%). This creates a very strong but still malleability, malleable steel. Eglin steel uses a combination of over a dozen different elements in varying amounts to create a relatively low-cost steel for use in bunker buster weapons. Hadfield steel (after Sir Robert Hadfield) or manganese steel contains 12–14% manganese which when abraded strain-hardens to form a very hard skin which resists wearing. Examples include Continuous track, tank tracks, bulldozer#Blade, bulldozer blade edges, and cutting blades on the jaws of life.


Standards

Most of the more commonly used steel alloys are categorized into various grades by standards organizations. For example, the Society of Automotive Engineers has a series of SAE steel grades, grades defining many types of steel. The ASTM International, American Society for Testing and Materials has a separate set of standards, which define alloys such as A36 steel, the most commonly used structural steel in the United States. The Japanese Industrial Standards, JIS also defines a series of steel grades that are being used extensively in Japan as well as in developing countries.


Uses

Iron and steel are used widely in the construction of roads, railways, other infrastructure, appliances, and buildings. Most large modern structures, such as stadium#The modern stadium, stadiums and skyscrapers, bridges, and airports, are supported by a steel skeleton. Even those with a concrete structure employ steel for reinforcing. In addition, it sees widespread use in major appliances and automobile, cars. Despite the growth in usage of aluminium, it is still the main material for car bodies. Steel is used in a variety of other construction materials, such as bolts, nail (engineering), nails and screws and other household products and cooking utensils. Other common applications include shipbuilding, pipeline transport, pipelines, mining, offshore construction, aerospace, white goods (e.g. washing machines), heavy equipment such as bulldozers, office furniture, steel wool,
tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment. Although many animals use simple tools, only human beings, whose use of stone tool A stone tool is, in the most general sense, a ...

tool
, and armour in the form of personal vests or vehicle armour (better known as rolled homogeneous armour in this role).


Historical

Before the introduction of the
Bessemer process The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is steelmaking, removal of impurities from the iron by oxi ...

Bessemer process
and other modern production techniques, steel was expensive and was only used where no cheaper alternative existed, particularly for the cutting edge of knives, razors, swords, and other items where a hard, sharp edge was needed. It was also used for spring (device), springs, including those used in clock, clocks and watches. With the advent of speedier and thriftier production methods, steel has become easier to obtain and much cheaper. It has replaced wrought iron for a multitude of purposes. However, the availability of plastics in the latter part of the 20th century allowed these materials to replace steel in some applications due to their lower fabrication cost and weight. Carbon fiber is replacing steel in some cost insensitive applications such as sports equipment and high-end automobiles.


Long steel

* As reinforcing bars and mesh in reinforced concrete * Railroad tracks * Structural steel in modern buildings and bridges * Wires * Input to reforging applications


Flat carbon steel

* Major appliances * Magnetic cores * The inside and outside body of automobiles, trains, and ships.


Weathering steel (COR-TEN)

* Intermodal containers * Outdoor sculptures * Architecture * Highliner train cars


Stainless steel

* Cutlery * Rulers * Surgical instruments * Watches * Guns * passenger car (rail), Rail passenger vehicles * Tablet computer, Tablets * Waste container, Trash Cans * Body piercing jewellery * Inexpensive Ring (jewellery), rings * Components of spacecraft and space stations


Low-background steel

Steel manufactured after World War II became radioactive contamination, contaminated with radionuclides by nuclear weapons testing. Low-background steel, steel manufactured prior to 1945, is used for certain radiation-sensitive applications such as Geiger counters and radiation shielding.


See also

* Bulat steel * Carbon steel * Damascus steel * Galvanising * Global steel industry trends * Iron in folklore * Knife metal * Machinability * Noric steel * Pelletizing * Rolling (metalworking), Rolling * Rolling mill * Rust Belt * Second Industrial Revolution * Silicon steel * Steel abrasive * Steel mill * Tamahagane, used in Japanese swords * Tinning, Tinplate * Toledo steel * Wootz steel


References


Bibliography

* * * Verein Deutscher Eisenhüttenleute (Ed.). ''Steel – A Handbook for Materials Research and Engineering, Volume 1: Fundamentals''. Springer-Verlag Berlin, Heidelberg and Verlag Stahleisen, Düsseldorf 1992, 737 p. . * Verein Deutscher Eisenhüttenleute (Ed.). ''Steel – A Handbook for Materials Research and Engineering, Volume 2: Applications''. Springer-Verlag Berlin, Heidelberg and Verlag Stahleisen, Düsseldorf 1993, 839 pages, . *


Further reading

* Mark Reutter,
Making Steel: Sparrows Point and the Rise and Ruin of American Industrial Might
'. University of Illinois Press, 2005. * Duncan Burn,
The Economic History of Steelmaking, 1867–1939: A Study in Competition
'. Cambridge University Press, 1961. * Harukiyu Hasegawa,
The Steel Industry in Japan: A Comparison with Britain
'. Routledge, 1996. * J.C. Carr and W. Taplin,
History of the British Steel Industry
'. Harvard University Press, 1962. * H. Lee Scamehorn,
Mill & Mine: The Cf&I in the Twentieth Century
'. University of Nebraska Press, 1992. * Warren, Kenneth,
Big Steel: The First Century of the United States Steel Corporation, 1901–2001
'. University of Pittsburgh Press, 2001.


External links


Official website
of the World Steel Association (worldsteel) *
steeluniversity.org
Online steel education resources, an initiative of World Steel Association
Metallurgy for the Non-Metallurgist
from the American Society for Metals
MATDAT Database of Properties of Unalloyed, Low-Alloy and High-Alloy Steels
– obtained from published results of material testing {{Authority control Steel, 2nd-millennium BC introductions Building materials Roofing materials