Carbon steel: Difference between revisions

Content deleted Content added

Inline

Latest revision as of 20:01, 16 November 2024

Carbon steel is a steel with carbon content from about 0.05 up to 2.1 percent by weight. The definition of carbon steel from the American Iron and Steel Institute (AISI) states:

no minimum content is specified or required for chromium, cobalt, molybdenum, nickel, niobium, titanium, tungsten, vanadium, zirconium, or any other element to be added to obtain a desired alloying effect;
the specified minimum for copper does not exceed 0.40%;
or the specified maximum for any of the following elements does not exceed the percentages noted: manganese 1.65%; silicon 0.60%; copper 0.60%.^[1]

The term carbon steel may also be used in reference to steel which is not stainless steel; in this use carbon steel may include alloy steels. High carbon steel has many different uses such as milling machines, cutting tools (such as chisels) and high strength wires. These applications require a much finer microstructure, which improves the toughness.

As the carbon content percentage rises, steel has the ability to become harder and stronger through heat treating; however, it becomes less ductile. Regardless of the heat treatment, a higher carbon content reduces weldability. In carbon steels, the higher carbon content lowers the melting point.^[2]

Properties

Carbon steel is often divided into two main categories: low-carbon steel and high-carbon steel. It may also contain other elements, such as manganese, phosphorus, sulfur, and silicon, which can affect its properties. Carbon steel can be easily machined and welded, making it versatile for various applications. It can also be heat treated to improve its strength, hardness, and durability.

Carbon steel is susceptible to rust and corrosion, especially in environments with high moisture levels and/or salt. It can be shielded from corrosion by coating it with paint, varnish, or other protective material. Alternatively, it can be made from a stainless steel alloy that contains chromium, which provides excellent corrosion resistance. Carbon steel can be alloyed with other elements to improve its properties, such as by adding chromium and/or nickel to improve its resistance to corrosion and oxidation or adding molybdenum to improve its strength and toughness at high temperatures.

It is an environmentally friendly material, as it is easily recyclable and can be reused in various applications. It is energy-efficient to produce, as it requires less energy than other metals such as aluminium and copper.^{[citation needed]}

Type

Mild or low-carbon steel

Mild steel (iron containing a small percentage of carbon, strong and tough but not readily tempered), also known as plain-carbon steel and low-carbon steel, is now the most common form of steel because its price is relatively low while it provides material properties that are acceptable for many applications. Mild steel contains approximately 0.05–0.30% carbon^[1] making it malleable and ductile. Mild steel has a relatively low tensile strength, but it is cheap and easy to form. Surface hardness can be increased with carburization.^[3]

The density of mild steel is approximately 7.85 g/cm³ (7,850 kg/m³; 0.284 lb/cu in)^[4] and the Young's modulus is 200 GPa (29×10^⁶ psi).^[5]

Low-carbon steels^[6] display yield-point runout where the material has two yield points. The first yield point (or upper yield point) is higher than the second and the yield drops dramatically after the upper yield point. If a low-carbon steel is only stressed to some point between the upper and lower yield point then the surface develops Lüder bands.^[7] Low-carbon steels contain less carbon than other steels and are easier to cold-form, making them easier to handle.^[3] Typical applications of low carbon steel are car parts, pipes, construction, and food cans.^[8]

High-tensile steel

High-tensile steels are low-carbon, or steels at the lower end of the medium-carbon range,^{[citation needed]} which have additional alloying ingredients in order to increase their strength, wear properties or specifically tensile strength. These alloying ingredients include chromium, molybdenum, silicon, manganese, nickel, and vanadium. Impurities such as phosphorus and sulfur have their maximum allowable content restricted.

41xx steel
- 4140 steel
- 4145 steel
4340 steel
- 300M steel
EN25 steel – 2.521% nickel-chromium-molybdenum steel
EN26 steel

Higher-carbon steels

Carbon steels which can successfully undergo heat-treatment have a carbon content in the range of 0.30–1.70% by weight. Trace impurities of various other elements can significantly affect the quality of the resulting steel. Trace amounts of sulfur in particular make the steel red-short, that is, brittle and crumbly at high working temperatures. Low-alloy carbon steel, such as A36 grade, contains about 0.05% sulfur and melt around 1,426–1,538 °C (2,600–2,800 °F).^[9] Manganese is often added to improve the hardenability of low-carbon steels. These additions turn the material into a low-alloy steel by some definitions, but AISI's definition of carbon steel allows up to 1.65% manganese by weight. There are two types of higher carbon steels which are high carbon steel and the ultra high carbon steel. The reason for the limited use of high carbon steel is that it has extremely poor ductility and weldability and has a higher cost of production. The applications best suited for the high carbon steels is its use in the spring industry, farm industry, and in the production of wide range of high-strength wires.^[10]^[11]

AISI classification

The following classification method is based on the American AISI/SAE standard. Other international standards including DIN (Germany), GB (China), BS/EN (UK), AFNOR (France), UNI (Italy), SS (Sweden) , UNE (Spain), JIS (Japan), ASTM standards, and others.

Carbon steel is broken down into four classes based on carbon content:^[1]

Low-carbon steel

Low-carbon steel has 0.05 to 0.15% carbon (plain carbon steel) content.^[1]

Medium-carbon steel

Medium-carbon steel has approximately 0.3–0.5% carbon content.^[1] It balances ductility and strength and has good wear resistance. It is used for large parts, forging and automotive components.^[12]^[13]

High-carbon steel

High-carbon steel has approximately 0.6 to 1.0% carbon content.^[1] It is very strong, used for springs, edged tools, and high-strength wires.^[14]

Ultra-high-carbon steel

Ultra-high-carbon steel has approximately 1.25–2.0% carbon content.^[1] Steels that can be tempered to great hardness. Used for special purposes such as (non-industrial-purpose) knives, axles, and punches. Most steels with more than 2.5% carbon content are made using powder metallurgy.

Heat treatment

The purpose of heat treating carbon steel is to change the mechanical properties of steel, usually ductility, hardness, yield strength, or impact resistance. Note that the electrical and thermal conductivity are only slightly altered. As with most strengthening techniques for steel, Young's modulus (elasticity) is unaffected. All treatments of steel trade ductility for increased strength and vice versa. Iron has a higher solubility for carbon in the austenite phase; therefore all heat treatments, except spheroidizing and process annealing, start by heating the steel to a temperature at which the austenitic phase can exist. The steel is then quenched (heat drawn out) at a moderate to low rate allowing carbon to diffuse out of the austenite forming iron-carbide (cementite) and leaving ferrite, or at a high rate, trapping the carbon within the iron thus forming martensite. The rate at which the steel is cooled through the eutectoid temperature (about 727 °C or 1,341 °F) affects the rate at which carbon diffuses out of austenite and forms cementite. Generally speaking, cooling swiftly will leave iron carbide finely dispersed and produce a fine grained pearlite and cooling slowly will give a coarser pearlite. Cooling a hypoeutectoid steel (less than 0.77 wt% C) results in a lamellar-pearlitic structure of iron carbide layers with α-ferrite (nearly pure iron) between. If it is hypereutectoid steel (more than 0.77 wt% C) then the structure is full pearlite with small grains (larger than the pearlite lamella) of cementite formed on the grain boundaries. A eutectoid steel (0.77% carbon) will have a pearlite structure throughout the grains with no cementite at the boundaries. The relative amounts of constituents are found using the lever rule. The following is a list of the types of heat treatments possible:

Spheroidizing: Spheroidite forms when carbon steel is heated to approximately 700 °C (1,300 °F) for over 30 hours. Spheroidite can form at lower temperatures but the time needed drastically increases, as this is a diffusion-controlled process. The result is a structure of rods or spheres of cementite within primary structure (ferrite or pearlite, depending on which side of the eutectoid you are on). The purpose is to soften higher carbon steels and allow more formability. This is the softest and most ductile form of steel.^[15]
Full annealing: A hypoeutectoid carbon steel (carbon composition smaller than the eutectoid one) is heated to approximately 30 to 50 °C (86 to 120 °F) above the austenictic temperature (A₃), whereas a hypereutectoid steel is heated to a temperature above the eutectoid one (A₁) for a certain number of hours; this ensures all the ferrite transforms into austenite (although cementite might still exist in hypereutectoid steels). The steel must then be cooled slowly, in the realm of 20 °C (36 °F) per hour. Usually it is just furnace cooled, where the furnace is turned off with the steel still inside. This results in a coarse pearlitic structure, which means the "bands" of pearlite are thick.^[16] Fully annealed steel is soft and ductile, with no internal stresses, which is often necessary for cost-effective forming. Only spheroidized steel is softer and more ductile.^[17]
Process annealing: A process used to relieve stress in a cold-worked carbon steel with less than 0.3% C. The steel is usually heated to 550 to 650 °C (1,000 to 1,200 °F) for 1 hour, but sometimes temperatures as high as 700 °C (1,300 °F). The image above shows the process annealing area.
Isothermal annealing: It is a process in which hypoeutectoid steel is heated above the upper critical temperature. This temperature is maintained for a time and then reduced to below the lower critical temperature and is again maintained. It is then cooled to room temperature. This method eliminates any temperature gradient.
Normalizing: Carbon steel is heated to approximately 550 °C (1,000 °F) for 1 hour; this ensures the steel completely transforms to austenite. The steel is then air-cooled, which is a cooling rate of approximately 38 °C (100 °F) per minute. This results in a fine pearlitic structure, and a more-uniform structure. Normalized steel has a higher strength than annealed steel; it has a relatively high strength and hardness.^[18]
Quenching: Carbon steel with at least 0.4 wt% C is heated to normalizing temperatures and then rapidly cooled (quenched) in water, brine, or oil to the critical temperature. The critical temperature is dependent on the carbon content, but as a general rule is lower as the carbon content increases. This results in a martensitic structure; a form of steel that possesses a super-saturated carbon content in a deformed body-centered cubic (BCC) crystalline structure, properly termed body-centered tetragonal (BCT), with much internal stress. Thus quenched steel is extremely hard but brittle, usually too brittle for practical purposes. These internal stresses may cause stress cracks on the surface. Quenched steel is approximately three times harder (four with more carbon) than normalized steel.^[19]
Martempering (marquenching): Martempering is not actually a tempering procedure, hence the term marquenching. It is a form of isothermal heat treatment applied after an initial quench, typically in a molten salt bath, at a temperature just above the "martensite start temperature". At this temperature, residual stresses within the material are relieved and some bainite may be formed from the retained austenite which did not have time to transform into anything else. In industry, this is a process used to control the ductility and hardness of a material. With longer marquenching, the ductility increases with a minimal loss in strength; the steel is held in this solution until the inner and outer temperatures of the part equalize. Then the steel is cooled at a moderate speed to keep the temperature gradient minimal. Not only does this process reduce internal stresses and stress cracks, but it also increases impact resistance.^[20]
Tempering: This is the most common heat treatment encountered because the final properties can be precisely determined by the temperature and time of the tempering. Tempering involves reheating quenched steel to a temperature below the eutectoid temperature and then cooling. The elevated temperature allows very small amounts spheroidite to form, which restores ductility but reduces hardness. Actual temperatures and times are carefully chosen for each composition.^[21]
Austempering: The austempering process is the same as martempering, except the quench is interrupted and the steel is held in the molten salt bath at temperatures between 205 and 540 °C (400 and 1,000 °F), and then cooled at a moderate rate. The resulting steel, called bainite, produces an acicular microstructure in the steel that has great strength (but less than martensite), greater ductility, higher impact resistance, and less distortion than martensite steel. The disadvantage of austempering is it can be used only on a few sheets of steel, and it requires a special salt bath.^[22]

Case hardening

Case hardening processes harden only the exterior of the steel part, creating a hard, wear-resistant skin (the "case") but preserving a tough and ductile interior. Carbon steels are not very hardenable meaning they can not be hardened throughout thick sections. Alloy steels have a better hardenability, so they can be through-hardened and do not require case hardening. This property of carbon steel can be beneficial, because it gives the surface good wear characteristics but leaves the core flexible and shock-absorbing.

Forging temperature of steel

^[23]

Steel type	Maximum forging temperature		Burning temperature
Steel type	(°F)	(°C)	(°F)	(°C)
1.5% carbon	1,920	1,049	2,080	1,140
1.1% carbon	1,980	1,082	2,140	1,171
0.9% carbon	2,050	1,121	2,230	1,221
0.5% carbon	2,280	1,249	2,460	1,349
0.2% carbon	2,410	1,321	2,680	1,471
3.0% nickel steel	2,280	1,249	2,500	1,371
3.0% nickel–chromium steel	2,280	1,249	2,500	1,371
5.0% nickel (case-hardening) steel	2,320	1,271	2,640	1,449
Chromium–vanadium steel	2,280	1,249	2,460	1,349
High-speed steel	2,370	1,299	2,520	1,385
Stainless steel	2,340	1,282	2,520	1,385
Austenitic chromium–nickel steel	2,370	1,299	2,590	1,420
Silico-manganese spring steel	2,280	1,249	2,460	1,350

References

^ ^a ^b ^c ^d ^e ^f ^g "Classification of Carbon and Low-Alloy Steels". Total Materia. Key to Metals. November 2001. Retrieved 29 April 2023.
^ Knowles, Peter Reginald (1987), Design of structural steelwork (2nd ed.), Taylor & Francis, p. 1, ISBN 978-0-903384-59-9.
^ ^a ^b "Low-carbon steel". eFunda. Retrieved 29 April 2023.
^ Elert, Glenn, Density of Steel, retrieved 23 April 2009.
^ Modulus of Elasticity, Strength Properties of Metals – Iron and Steel, retrieved 23 April 2009.
^ "1020 Steel". steel-bar.com. 21 May 2022. Archived from the original on 1 May 2023.{{cite web}}: CS1 maint: unfit URL (link)
^ DeGarmo, Black & Kohser 2003, p. 377
^ "What Are the Different Types of Steel?". Metal Exponents. 18 August 2020. Retrieved 29 January 2021.
^ "MSDS, carbon steel" (PDF). Gerdau AmeriSteel. Archived from the original on 18 October 2006.{{cite web}}: CS1 maint: unfit URL (link)
^ "Introduction to Carbon Steel | Types, Properties, Uses and Applications". MaterialsWiz. Retrieved 18 August 2022.
^ Vitzmetals
^ Nishimura, Naoya; Murase, Katsuhiko; Ito, Toshihiro; Watanabe, Takeru; Nowak, Roman (2012). "Ultrasonic detection of spall damage induced by low-velocity repeated impact". Central European Journal of Engineering. 2 (4): 650–655. Bibcode:2012CEJE....2..650N. doi:10.2478/s13531-012-0013-5.
^ "Medium-carbon steel". eFunda. Retrieved 29 April 2023.
^ "High-carbon steel". eFunda. Retrieved 29 April 2023.
^ Smith & Hashemi 2006, p. 388
^ Alvarenga HD, Van de Putte T, Van Steenberge N, Sietsma J, Terryn H (October 2014). "Influence of Carbide Morphology and Microstructure on the Kinetics of Superficial Decarburization of C-Mn Steels". Metall Mater Trans A. 46 (1): 123–133. Bibcode:2015MMTA...46..123A. doi:10.1007/s11661-014-2600-y. S2CID 136871961.
^ Smith & Hashemi 2006, p. 386
^ Smith & Hashemi 2006, pp. 386–387
^ Smith & Hashemi 2006, pp. 373–377
^ Smith & Hashemi 2006, pp. 389–390
^ Smith & Hashemi 2006, pp. 387–388
^ Smith & Hashemi 2006, p. 391
^ Brady, George S.; Clauser, Henry R.; Vaccari A., John (1997). Materials Handbook (14th ed.). New York, NY: McGraw-Hill. ISBN 0-07-007084-9.

Bibliography

DeGarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.), Wiley, ISBN 0-471-65653-4.
Oberg, E.; et al. (1996), Machinery's Handbook (25th ed.), Industrial Press Inc, ISBN 0-8311-2599-3.
Smith, William F.; Hashemi, Javad (2006), Foundations of Materials Science and Engineering (4th ed.), McGraw-Hill, ISBN 0-07-295358-6.

[kts-1] ^ ^a ^b ^c ^d ^e ^f ^g "Classification of Carbon and Low-Alloy Steels". Total Materia. Key to Metals. November 2001. Retrieved 29 April 2023.

[2] Knowles, Peter Reginald (1987), Design of structural steelwork (2nd ed.), Taylor & Francis, p. 1, ISBN 978-0-903384-59-9.

[efunda-3] "Low-carbon steel". eFunda. Retrieved 29 April 2023.

[4] Elert, Glenn, Density of Steel, retrieved 23 April 2009.

[5] Modulus of Elasticity, Strength Properties of Metals – Iron and Steel, retrieved 23 April 2009.

[6] "1020 Steel". steel-bar.com. 21 May 2022. Archived from the original on 1 May 2023.{{cite web}}: CS1 maint: unfit URL (link)

[7] DeGarmo, Black & Kohser 2003, p. 377

[8] "What Are the Different Types of Steel?". Metal Exponents. 18 August 2020. Retrieved 29 January 2021.

[9] "MSDS, carbon steel" (PDF). Gerdau AmeriSteel. Archived from the original on 18 October 2006.{{cite web}}: CS1 maint: unfit URL (link)

[10] "Introduction to Carbon Steel | Types, Properties, Uses and Applications". MaterialsWiz. Retrieved 18 August 2022.

[11] Vitzmetals

[12] Nishimura, Naoya; Murase, Katsuhiko; Ito, Toshihiro; Watanabe, Takeru; Nowak, Roman (2012). "Ultrasonic detection of spall damage induced by low-velocity repeated impact". Central European Journal of Engineering. 2 (4): 650–655. Bibcode:2012CEJE....2..650N. doi:10.2478/s13531-012-0013-5.

[13] "Medium-carbon steel". eFunda. Retrieved 29 April 2023.

[14] "High-carbon steel". eFunda. Retrieved 29 April 2023.

[15] Smith & Hashemi 2006, p. 388

[Alvarenga-16] Alvarenga HD, Van de Putte T, Van Steenberge N, Sietsma J, Terryn H (October 2014). "Influence of Carbide Morphology and Microstructure on the Kinetics of Superficial Decarburization of C-Mn Steels". Metall Mater Trans A. 46 (1): 123–133. Bibcode:2015MMTA...46..123A. doi:10.1007/s11661-014-2600-y. S2CID 136871961.

[17] Smith & Hashemi 2006, p. 386

[18] Smith & Hashemi 2006, pp. 386–387

[19] Smith & Hashemi 2006, pp. 373–377

[20] Smith & Hashemi 2006, pp. 389–390

[21] Smith & Hashemi 2006, pp. 387–388

[22] Smith & Hashemi 2006, p. 391

[Mat_hand-23] Brady, George S.; Clauser, Henry R.; Vaccari A., John (1997). Materials Handbook (14th ed.). New York, NY: McGraw-Hill. ISBN 0-07-007084-9.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

@@ Line 1: / Line 1: @@
+{{short description|Steel in which the main interstitial alloying constituent is carbon}}
-{{Use dmy dates|date=June 2013}}
+{{Use dmy dates|date=April 2023}}
 {{Steels}}
-'''Carbon steel''' is [[steel]] in which the main interstitial [[alloy]]ing constituent is [[carbon]] in the range of 0.12–2.0%. The [[American Iron and Steel Institute]] (AISI) defines that:
+'''Carbon steel''' is a [[steel]] with [[carbon]] content from about 0.05 up to 2.1 percent by weight. The definition of carbon steel from the [[American Iron and Steel Institute]] (AISI) states:
+* no minimum content is specified or required for [[chromium]], [[cobalt]], [[molybdenum]], [[nickel]], [[niobium]], [[titanium]], [[tungsten]], [[vanadium]], [[zirconium]], or any other element to be added to obtain a desired alloying effect;
-: Steel is considered to be carbon steel
+* the specified minimum for [[copper]] does not exceed 0.40%;
+* or the specified maximum for any of the following elements does not exceed the percentages noted: [[manganese]] 1.65%; [[silicon]] 0.60%; copper 0.60%.<ref name=kts/>
+The term ''carbon steel'' may also be used in reference to steel which is not [[stainless steel]]; in this use carbon steel may include [[alloy steel]]s. High carbon steel has many different uses such as milling machines, cutting tools (such as [[chisel]]s) and high strength wires. These applications require a much finer microstructure, which improves the toughness.
-::&nbsp;&nbsp; when no minimum content is specified or required for [[chromium]], [[cobalt]], [[molybdenum]], [[nickel]], [[niobium]], [[titanium]], [[tungsten]], [[vanadium]] or [[zirconium]], or any other element to be added to obtain a desired alloying effect; <br>&nbsp;&nbsp; when the specified minimum for copper does not exceed 0.40 percent; <br>&nbsp;&nbsp; or when the maximum content specified for any of the following elements does not exceed the percentages noted: [[manganese]] 1.65, [[silicon]] 0.60, [[copper]] 0.60.<ref name=kts/>
+As the carbon content percentage rises, steel has the ability to become [[hardness|harder]] and [[strength of materials|stronger]] through [[heat treating]]; however, it becomes less [[ductile]]. Regardless of the heat treatment, a higher carbon content reduces [[weldability]].<!-- See the weldability article for a ref --> In carbon steels, the higher carbon content lowers the melting point.<ref>{{Citation | last = Knowles | first = Peter Reginald | title = Design of structural steelwork | page = 1 | publisher = Taylor & Francis | year = 1987 | edition = 2nd | url = https://books.google.com/books?id=U6wX-3C8ygcC&pg=PA1 | isbn = 978-0-903384-59-9 | postscript =.}}</ref>
-The term "carbon steel" may also be used in reference to steel which is not [[stainless steel]]; in this use carbon steel may include [[alloy steel]]s.
+== Properties ==
-As the carbon percentage content rises, steel has the ability to become [[hardness|harder]] and [[strength of materials|stronger]] through [[heat treating]]; however, it becomes less [[ductile]]. Regardless of the heat treatment, a higher carbon content reduces [[weldability]].<!-- See the weldability article for a ref --> In carbon steels, the higher carbon content lowers the melting point.<ref>{{Citation | last = Knowles | first = Peter Reginald | title = Design of structural steelwork | page = 1 | publisher = Taylor & Francis | year = 1987 | edition = 2nd | url = http://books.google.com/books?id=U6wX-3C8ygcC&pg=PA1 | isbn = 978-0-903384-59-9 | postscript =.}}</ref>
+Carbon steel is often divided into two main categories: low-carbon steel and high-carbon steel. It may also contain other elements, such as manganese, phosphorus, sulfur, and silicon, which can affect its properties. Carbon steel can be easily machined and welded, making it versatile for various applications. It can also be heat treated to improve its strength, hardness, and durability.
+Carbon steel is susceptible to rust and corrosion, especially in environments with high moisture levels and/or salt. It can be shielded from corrosion by coating it with paint, varnish, or other protective material. Alternatively, it can be made from a stainless steel alloy that contains chromium, which provides excellent corrosion resistance. Carbon steel can be alloyed with other elements to improve its properties, such as by adding chromium and/or nickel to improve its resistance to corrosion and oxidation or adding molybdenum to improve its strength and toughness at high temperatures.
+It is an environmentally friendly material, as it is easily recyclable and can be reused in various applications. It is energy-efficient to produce, as it requires less energy than other metals such as aluminium and copper.{{cn|date=September 2024}}
 ==Type==
 {{see also|SAE steel grades}}
-==={{Anchor|Mild steel}}Mild and low-carbon steel===
+==={{Anchor|Mild steel}}Mild or low-carbon steel===
-Mild steel{{define?|date=July 2014}}, also known as '''plain-carbon steel''', is now the most common form of steel because its price is relatively low while it provides material properties that are acceptable for many applications. Low-carbon steel contains approximately 0.05–0.15% carbon<ref name=kts>[http://www.keytometals.com/Articles/Art62.htm "Classification of Carbon and Low-Alloy Steels"]</ref> making it malleable and ductile. Mild steel has a relatively low tensile strength, but it is cheap and easy to form; surface hardness can be increased through [[carburization|carburizing]].<ref>[http://efunda.com/materials/alloys/alloy_home/../carbon_steels/low_carbon.cfm Engineering fundamentals page on low-carbon steel]</ref>
+Mild steel (iron containing a small percentage of carbon, strong and tough but not readily tempered), also known as plain-carbon steel and low-carbon steel, is now the most common form of steel because its price is relatively low while it provides material properties that are acceptable for many applications. Mild steel contains approximately 0.05–0.30% carbon<ref name="kts">{{cite web |title=Classification of Carbon and Low-Alloy Steels |url=http://www.totalmateria.com/articles/Art62.htm |website=Total Materia |publisher=Key to Metals |access-date=29 April 2023 |date=November 2001}}</ref> making it malleable and ductile. Mild steel has a relatively low tensile strength, but it is cheap and easy to form. Surface hardness can be increased with [[carburization]].<ref name="efunda">{{cite web |title=Low-carbon steel |url=https://www.efunda.com/materials/alloys/carbon_steels/low_carbon.cfm |website=eFunda |access-date=29 April 2023}}</ref>
+The density of mild steel is approximately {{cvt|7.85|g/cm3|kg/m3 lb/in3}}<ref>{{citation |last= Elert |first= Glenn |title= Density of Steel |url= https://hypertextbook.com/facts/2004/KarenSutherland.shtml |access-date= 23 April 2009}}.</ref> and the [[Young's modulus]] is {{convert|200|GPa|e6psi|abbr=on}}.<ref>{{citation |title= Modulus of Elasticity, Strength Properties of Metals – Iron and Steel |url= https://www.engineersedge.com/manufacturing_spec/properties_of_metals_strength.htm |access-date= 23 April 2009}}.</ref>
+Low-carbon steels<ref>{{cite web|url=https://steel-bar.com/1020-steel/|archive-url=https://web.archive.org/web/20230501104400/https://steel-bar.com/1020-steel/|url-status=usurped|archive-date=1 May 2023|title=1020 Steel|website=steel-bar.com|date=21 May 2022 }}</ref> display ''yield-point runout'' where the material has two [[yield point]]s. The first yield point (or upper yield point) is higher than the second and the yield drops dramatically after the upper yield point. If a low-carbon steel is only stressed to some point between the upper and lower yield point then the surface develops [[Lüder bands]].<ref>{{harvnb|DeGarmo|Black|Kohser|2003|p=377}}</ref> Low-carbon steels contain less carbon than other steels and are easier to cold-form, making them easier to handle.<ref name="efunda" /> Typical applications of low carbon steel are car parts, pipes, construction, and food cans.<ref>{{Cite web|title=What Are the Different Types of Steel? |website=Metal Exponents |date=18 August 2020 |url=https://metalexponents.com/blog/different-types-steel/|access-date=29 January 2021}}</ref>
+==== High-tensile steel ====
-It is often used when large quantities of steel are needed, for example as [[structural steel]]. The density of mild steel is approximately 7.85&nbsp;g/cm<sup>3</sup> (7850&nbsp;kg/m<sup>3</sup> or 0.284&nbsp;lb/in<sup>3</sup>)<ref>{{Citation | last = Elert | first = Glenn | title = Density of Steel | url = http://hypertextbook.com/facts/2004/KarenSutherland.shtml | accessdate = 23 April 2009}}.</ref> and the [[Young's modulus]] is {{convert|210|GPa|psi|abbr=on}}.<ref>{{Citation | title = Modulus of Elasticity, Strength Properties of Metals – Iron and Steel | url = http://www.engineersedge.com/manufacturing_spec/properties_of_metals_strength.htm | accessdate = 23 April 2009}}.</ref>
+High-tensile steels are low-carbon, or steels at the lower end of the medium-carbon range,{{citation needed|date=June 2019}} which have additional alloying ingredients in order to increase their strength, wear properties or specifically [[tensile strength]]. These alloying ingredients include [[chromium]], [[molybdenum]], [[silicon]], [[manganese]], [[nickel]], and [[vanadium]]. Impurities such as [[phosphorus]] and [[sulfur]] have their maximum allowable content restricted.
+* [[41xx steel]]
-Low-carbon steels suffer from ''yield-point runout'' where the material has two [[yield point]]s. The first yield point (or upper yield point) is higher than the second and the yield drops dramatically after the upper yield point. If a low-carbon steel is only stressed to some point between the upper and lower yield point then the surface may develop [[Lüder bands]].<ref>Degarmo, p. 377.</ref> Low-carbon steels contain less carbon than other steels and are easier to cold-form, making them easier to handle.<ref>{{cite web| url= http://www.efunda.com/materials/alloys/carbon_steels/low_carbon.cfm|title=Low-carbon steels
+** [[4140 steel]]
-|publisher= efunda |accessdate=2012-05-25}}</ref>
+** [[4145 steel]]
+* [[4340 steel]]
+** [[300M steel]]
+* [[EN25 steel]] &ndash; 2.521% nickel-chromium-molybdenum steel
+* [[EN26 steel]]
 ===Higher-carbon steels===
-Carbon steels which can successfully undergo heat-treatment have a carbon content in the range of 0.30–1.70% by weight. Trace impurities of various other [[chemical element|element]]s can have a significant effect on the quality of the resulting steel. Trace amounts of [[sulfur]] in particular make the steel [[red-short]], that is, brittle and crumbly at working temperatures. Low-alloy carbon steel, such as [[A36 steel|A36]] grade, contains about 0.05% sulfur and melts around {{convert|1426|–|1538|C|F}}.<ref>[http://www.ameristeel.com/products/msds/docs/carbon_steel.pdf Ameristeel article on carbon steel]</ref> [[Manganese]] is often added to improve the [[hardenability]] of low-carbon steels. These additions turn the material into a [[low-alloy steel]] by some definitions, but [[American Iron and Steel Institute|AISI]]'s definition of carbon steel allows up to 1.65% manganese by weight.
+Carbon steels which can successfully undergo heat-treatment have a carbon content in the range of 0.30–1.70% by weight. Trace impurities of various other [[chemical element|element]]s can significantly affect the quality of the resulting steel. Trace amounts of [[sulfur]] in particular make the steel [[red-short]], that is, brittle and crumbly at high working temperatures. Low-alloy carbon steel, such as [[A36 steel|A36]] grade, contains about 0.05% sulfur and melt around {{convert|1426|–|1538|C|F|sigfig=2}}.<ref>{{cite web |url=http://www.ameristeel.com/products/msds/docs/carbon_steel.pdf |title=MSDS, carbon steel |publisher=[[Gerdau]] [[AmeriSteel]] |url-status=usurped |archive-url=https://web.archive.org/web/20061018015022/http://www.ameristeel.com/products/msds/docs/carbon_steel.pdf |archive-date=18 October 2006}}</ref> [[Manganese]] is often added to improve the [[hardenability]] of low-carbon steels. These additions turn the material into a [[low-alloy steel]] by some definitions, but [[American Iron and Steel Institute|AISI]]'s definition of carbon steel allows up to 1.65% manganese by weight.
+There are two types of higher carbon steels which are high carbon steel and the ultra high carbon steel. The reason for the limited use of high carbon steel is that it has extremely poor ductility and weldability and has a higher cost of production. The applications best suited for the high carbon steels is its use in the spring industry, farm industry, and in the production of wide range of high-strength wires.<ref>{{cite web |title=Introduction to Carbon Steel {{!}} Types, Properties, Uses and Applications |url=https://www.materialswiz.com/2022/08/Introduction-to-Carbon-Steel-Types-Properties-Uses-and-Applications.html |website=MaterialsWiz |access-date=18 August 2022}}</ref><ref>[https://vitzmetals.com/ Vitzmetals]</ref>
+==AISI classification==
-==TypeS==
 {{see also|SAE steel grades}}
+The following classification method is based on the American [[SAE steel grades|AISI/SAE standard]]. Other international standards including [[Deutsches Institut für Normung|DIN]] (Germany), GB (China), [[British Standards|BS/EN]] (UK), AFNOR (France), UNI (Italy), SS (Sweden) , UNE (Spain), JIS (Japan), ASTM standards, and others.
-Carbon steel is broken down into four classes based on carbon content:
+Carbon steel is broken down into four classes based on carbon content:<ref name="kts" />
 ===Low-carbon steel===
-.05-0.3% carbon content.
+Low-carbon steel has 0.05 to 0.15% carbon (plain carbon steel) content.<ref name=kts/>
 ===Medium-carbon steel===
-Approximately 0.250–0.6% carbon content.<ref name=kts/> Balances ductility and strength and has good wear resistance; used for large parts, forging and automotive components.<ref>{{cite journal|last=Nishimura|first=Naoya|author2=Murase, Katsuhiko |author3=Ito, Toshihiro |author4=Watanabe, Takeru |author5= Nowak, Roman |title=Ultrasonic detection of spall damage induced by low-velocity repeated impact|journal=Central European Journal of Engineering|volume=2|issue=4|pages=650–655|doi=10.2478/s13531-012-0013-5}}</ref><ref>[http://efunda.com/materials/alloys/alloy_home/../carbon_steels/medium_carbon.cfm Engineering fundamentals page on medium-carbon steel]</ref>
+Medium-carbon steel has approximately 0.3–0.5% carbon content.<ref name=kts/> It balances ductility and strength and has good wear resistance. It is used for large parts, forging and automotive components.<ref>{{cite journal |last=Nishimura |first=Naoya |author2=Murase, Katsuhiko |author3=Ito, Toshihiro |author4=Watanabe, Takeru |author5= Nowak, Roman |title=Ultrasonic detection of spall damage induced by low-velocity repeated impact |journal=Central European Journal of Engineering |volume=2 |issue=4 |pages=650–655 |doi=10.2478/s13531-012-0013-5 |year=2012 |bibcode=2012CEJE....2..650N |doi-access=free}}{{open access}}</ref><ref>{{cite web |title=Medium-carbon steel |url=https://www.efunda.com/materials/alloys/carbon_steels/medium_carbon.cfm |website=eFunda |access-date=29 April 2023}}</ref>
-===High-carbon steel (ASTM 304)===
+===High-carbon steel===
-Approximately 0.9–2.5% carbon content.<ref name=kts/> Very strong, used for springs and high-strength wires.<ref>[http://efunda.com/materials/alloys/alloy_home/../carbon_steels/high_carbon.cfm Engineering fundamentals page on high-carbon steel]</ref>
+High-carbon steel has approximately 0.6 to 1.0% carbon content.<ref name=kts/> It is very strong, used for springs, edged tools, and high-strength wires.<ref>{{cite web |title=High-carbon steel |url=https://www.efunda.com/materials/alloys/carbon_steels/high_carbon.cfm |website=eFunda |access-date=29 April 2023}}</ref>
 ===Ultra-high-carbon steel===
-Approximately 2.5–3.0% carbon content.<ref name=kts/> Steels that can be tempered to great hardness. Used for special purposes like (non-industrial-purpose) knives, axles or [[Punch (metalworking)|punches]]. Most steels with more than 2.5% carbon content are made using [[powder metallurgy]]. Note that steel with a carbon content above 2.14% is considered [[cast iron]].
+Ultra-high-carbon steel has approximately 1.25–2.0% carbon content.<ref name=kts/> Steels that can be tempered to great hardness. Used for special purposes such as (non-industrial-purpose) knives, axles, and [[punch (metalworking)|punches]]. Most steels with more than 2.5% carbon content are made using [[powder metallurgy]].
 ==Heat treatment==
-[[File:Heat transfer steel diag2.png|thumb|right|Iron-carbon [[phase diagram]], showing the temperature and carbon ranges for certain types of heat treatments.]]
+[[File:Heat transfer steel diag2.png|thumb|upright=1.15|Iron-carbon [[phase diagram]], showing the temperature and carbon ranges for certain types of heat treatments]]
 {{main|Heat treatment}}
-The purpose of heat treating carbon steel is to change the mechanical properties of steel, usually ductility, hardness, yield strength, or impact resistance. Note that the electrical and thermal conductivity are only slightly altered. As with most strengthening techniques for steel, [[Young's modulus]] (elasticity) is unaffected. All treatments of steel trade ductility for increased strength and vice versa. Iron has a higher solubility for carbon in the [[austenite]] phase; therefore all heat treatments, except spheroidizing and process annealing, start by heating the steel to a temperature at which the austenitic phase can exist. The steel is then quenched (heat drawn out) at a high rate causing cementite to precipitate and finally the remaining pure iron to solidify. The rate at which the steel is cooled through the [[eutectoid]] temperature affects the rate at which carbon diffuses out of austenite and forms cementite. Generally speaking, cooling swiftly will leave iron carbide finely dispersed and produce a fine grained [[pearlite]] (until the [[martensite]] critical temperature is reached) and cooling slowly will give a coarser pearlite. Cooling a hypoeutectoid steel (less than 0.77 wt% C) results in a lamellar-pearlitic structure of iron carbide layers with α-[[ferrite (iron)|ferrite]] (pure iron) between. If it is hypereutectoid steel (more than 0.77 wt% C) then the structure is full pearlite with small grains (larger than the pearlite lamella) of [[cementite]] scattered throughout. The relative amounts of constituents are found using the [[lever rule]]. The following is a list of the types of heat treatments possible:
+The purpose of heat treating carbon steel is to change the mechanical properties of steel, usually ductility, hardness, yield strength, or impact resistance. Note that the electrical and thermal conductivity are only slightly altered. As with most strengthening techniques for steel, [[Young's modulus]] (elasticity) is unaffected. All treatments of steel trade ductility for increased strength and vice versa. Iron has a higher solubility for carbon in the [[austenite]] phase; therefore all heat treatments, except spheroidizing and process annealing, start by heating the steel to a temperature at which the austenitic phase can exist. The steel is then quenched (heat drawn out) at a moderate to low rate allowing carbon to diffuse out of the austenite forming iron-carbide (cementite) and leaving ferrite, or at a high rate, trapping the carbon within the iron thus forming martensite. The rate at which the steel is cooled through the [[eutectoid]] temperature (about {{cvt|727|C|F|disp=or}}) affects the rate at which carbon diffuses out of austenite and forms cementite. Generally speaking, cooling swiftly will leave iron carbide finely dispersed and produce a fine grained [[pearlite]] and cooling slowly will give a coarser pearlite. Cooling a hypoeutectoid steel (less than 0.77 wt% C) results in a lamellar-pearlitic structure of iron carbide layers with α-[[Allotropes of iron|ferrite]] (nearly pure iron) between. If it is hypereutectoid steel (more than 0.77 wt% C) then the structure is full pearlite with small grains (larger than the pearlite lamella) of [[cementite]] formed on the grain boundaries. A eutectoid steel (0.77% carbon) will have a pearlite structure throughout the grains with no cementite at the boundaries. The relative amounts of constituents are found using the [[lever rule]]. The following is a list of the types of heat treatments possible:
-*'''Spheroidizing''': Spheroidite forms when carbon steel is heated to approximately 700 °C for over 30 hours. Spheroidite can form at lower temperatures but the time needed drastically increases, as this is a diffusion-controlled process. The result is a structure of rods or spheres of cementite within primary structure (ferrite or pearlite, depending on which side of the eutectoid you are on). The purpose is to soften higher carbon steels and allow more formability. This is the softest and most ductile form of steel. The image to the right shows where spheroidizing usually occurs.<ref>Smith, p. 388</ref>
+; Spheroidizing: Spheroidite forms when carbon steel is heated to approximately {{cvt|700|C|F|sigfig=2}} for over 30 hours. Spheroidite can form at lower temperatures but the time needed drastically increases, as this is a diffusion-controlled process. The result is a structure of rods or spheres of cementite within primary structure (ferrite or pearlite, depending on which side of the eutectoid you are on). The purpose is to soften higher carbon steels and allow more formability. This is the softest and most ductile form of steel.<ref>{{harvnb|Smith|Hashemi|2006|p=388}}</ref>
-*'''[[Annealing (metallurgy)|Full annealing]]''': Carbon steel is heated to approximately 40&nbsp;°C above Ac3 or Ac1 for 1 hour; this ensures all the [[Ferrite (iron)|ferrite]] transforms into [[austenite]] (although [[cementite]] might still exist if the carbon content is greater than the eutectoid). The steel must then be cooled slowly, in the realm of 20°C (36°F) per hour. Usually it is just furnace cooled, where the furnace is turned off with the steel still inside. This results in a coarse pearlitic structure, which means the "bands" of [[pearlite]] are thick.<ref name=Alvarenga>{{cite journal |author=Alvarenga HD, Van de Putte T, Van Steenberge N, Sietsma J, Terryn H |title=Influence of Carbide Morphology and Microstructure on the Kinetics of Superficial Decarburization of C-Mn Steels |journal=Metal Mater Trans A. |date=Apr 2009 |doi=10.1007/s11661-014-2600-y }}</ref> Fully annealed steel is soft and [[ductile]], with no internal stresses, which is often necessary for cost-effective forming. Only spheroidized steel is softer and more ductile.<ref>Smith, p. 386</ref>
+; [[Annealing (metallurgy)|Full annealing]]: A hypoeutectoid carbon steel (carbon composition smaller than the eutectoid one) is heated to approximately {{cvt|30|to|50|C|F|sigfig=2}} above the austenictic temperature (A<sub>3</sub>), whereas a hypereutectoid steel is heated to a temperature above the eutectoid one (A<sub>1</sub>) for a certain number of hours; this ensures all the [[Allotropes of iron|ferrite]] transforms into [[austenite]] (although [[cementite]] might still exist in hypereutectoid steels). The steel must then be cooled slowly, in the realm of 20&nbsp;°C (36&nbsp;°F) per hour. Usually it is just furnace cooled, where the furnace is turned off with the steel still inside. This results in a coarse pearlitic structure, which means the "bands" of [[pearlite]] are thick.<ref name=Alvarenga>{{cite journal |vauthors=Alvarenga HD, Van de Putte T, Van Steenberge N, Sietsma J, Terryn H |title=Influence of Carbide Morphology and Microstructure on the Kinetics of Superficial Decarburization of C-Mn Steels |journal=Metall Mater Trans A |volume=46 |pages=123–133 |date=Oct 2014 |issue=1 |doi=10.1007/s11661-014-2600-y |bibcode=2015MMTA...46..123A |s2cid=136871961 }}</ref> Fully annealed steel is soft and [[ductile]], with no internal stresses, which is often necessary for cost-effective forming. Only spheroidized steel is softer and more ductile.<ref>{{harvnb|Smith|Hashemi|2006|p=386}}</ref>
-*'''Process annealing''': A process used to relieve stress in a cold-worked carbon steel with less than 0.3 wt% C. The steel is usually heated up to 550–650&nbsp;°C for 1 hour, but sometimes temperatures as high as 700&nbsp;°C. The image rightward shows the area where process annealing occurs.
+; Process annealing: A process used to relieve stress in a cold-worked carbon steel with less than 0.3% C. The steel is usually heated to {{cvt|550|to|650|C|F|sigfig=2}} for 1 hour, but sometimes temperatures as high as {{cvt|700|C|F|sigfig=2}}. The image above shows the process annealing area.
-*'''Isothermal annealing''': It is a process in which hypoeutectoid steel is heated above the upper critical temperature and this temperature is maintained for a time and then the temperature is brought down below lower critical temperature and is again maintained. Then finally it is cooled at room temperature. This method rids any temperature gradient.
+; Isothermal annealing: It is a process in which hypoeutectoid steel is heated above the upper critical temperature. This temperature is maintained for a time and then reduced to below the lower critical temperature and is again maintained. It is then cooled to room temperature. This method eliminates any temperature gradient.
-*'''Normalizing''': Carbon steel is heated to approximately 55&nbsp;°C above Ac3 or Acm for 1 hour; this ensures the steel completely transforms to austenite. The steel is then air-cooled, which is a cooling rate of approximately {{convert|38|°C|°F}} per minute. This results in a fine pearlitic structure, and a more-uniform structure. Normalized steel has a higher strength than annealed steel; it has a relatively high strength and hardness.<ref>Smith, pp. 386–387</ref>
+; Normalizing: Carbon steel is heated to approximately {{cvt|550|C|F|sigfig=2}} for 1 hour; this ensures the steel completely transforms to austenite. The steel is then air-cooled, which is a cooling rate of approximately {{convert|38|C|F|sigfig=1}} per minute. This results in a fine pearlitic structure, and a more-uniform structure. Normalized steel has a higher strength than annealed steel; it has a relatively high strength and hardness.<ref>{{harvnb|Smith|Hashemi|2006|pp=386–387}}</ref>
-*'''[[Quenching]]''': Carbon steel with at least 0.4 wt% C is heated to normalizing temperatures and then rapidly cooled (quenched) in water, brine, or oil to the critical temperature. The critical temperature is dependent on the carbon content, but as a general rule is lower as the carbon content increases. This results in a martensitic structure; a form of steel that possesses a super-saturated carbon content in a deformed body-centered cubic (BCC) crystalline structure, properly termed body-centered tetragonal (BCT), with much internal stress. Thus quenched steel is extremely hard but [[brittle]], usually too brittle for practical purposes. These internal stresses cause stress cracks on the surface. Quenched steel is approximately three to four (with more carbon) fold harder than normalized steel.<ref>Smith, pp. 373–377</ref>
+; [[Quenching]]: Carbon steel with at least 0.4 wt% C is heated to normalizing temperatures and then rapidly cooled (quenched) in water, brine, or oil to the critical temperature. The critical temperature is dependent on the carbon content, but as a general rule is lower as the carbon content increases. This results in a martensitic structure; a form of steel that possesses a super-saturated carbon content in a deformed body-centered cubic (BCC) crystalline structure, properly termed body-centered tetragonal (BCT), with much internal stress. Thus quenched steel is extremely hard but [[brittle]], usually too brittle for practical purposes. These internal stresses may cause stress cracks on the surface. Quenched steel is approximately three times harder (four with more carbon) than normalized steel.<ref>{{harvnb|Smith|Hashemi|2006|pp=373–377}}</ref>
-*'''[[Martempering]] (Marquenching)''': Martempering is not actually a tempering procedure, hence the term "marquenching". It is a form of isothermal heat treatment applied after an initial quench of typically in a molten salt bath at a temperature right above the "martensite start temperature". At this temperature, residual stresses within the material are relieved and some bainite may be formed from the retained austenite which did not have time to transform into anything else. In industry, this is a process used to control the ductility and hardness of a material. With longer marquenching, the ductility increases with a minimal loss in strength; the steel is held in this solution until the inner and outer temperatures equalize. Then the steel is cooled at a moderate speed to keep the temperature gradient minimal. Not only does this process reduce internal stresses and stress cracks, but it also increases the impact resistance.<ref>Smith, pp. 389–390</ref>
+; [[Martempering]] (marquenching): Martempering is not actually a tempering procedure, hence the term ''marquenching''. It is a form of isothermal heat treatment applied after an initial quench, typically in a molten salt bath, at a temperature just above the "martensite start temperature". At this temperature, residual stresses within the material are relieved and some bainite may be formed from the retained austenite which did not have time to transform into anything else. In industry, this is a process used to control the ductility and hardness of a material. With longer marquenching, the ductility increases with a minimal loss in strength; the steel is held in this solution until the inner and outer temperatures of the part equalize. Then the steel is cooled at a moderate speed to keep the temperature gradient minimal. Not only does this process reduce internal stresses and stress cracks, but it also increases impact resistance.<ref>{{harvnb|Smith|Hashemi|2006|pp=389–390}}</ref>
+; [[Tempering (metallurgy)|Tempering]]: This is the most common heat treatment encountered because the final properties can be precisely determined by the temperature and time of the tempering. Tempering involves reheating quenched steel to a temperature below the [[eutectoid]] temperature and then cooling. The elevated temperature allows very small amounts spheroidite to form, which restores ductility but reduces hardness. Actual temperatures and times are carefully chosen for each composition.<ref>{{harvnb|Smith|Hashemi|2006|pp=387–388}}</ref>
+; [[Austempering]]: The austempering process is the same as martempering, except the quench is interrupted and the steel is held in the molten salt bath at temperatures between {{cvt|205|and|540|C|F|sigfig=2}}, and then cooled at a moderate rate. The resulting steel, called bainite, produces an acicular microstructure in the steel that has great strength (but less than martensite), greater ductility, higher impact resistance, and less distortion than martensite steel. The disadvantage of austempering is it can be used only on a few sheets of steel, and it requires a special salt bath.<ref>{{harvnb|Smith|Hashemi|2006|p=391}}</ref>
-*'''Quench and [[Tempering (metallurgy)|tempering]]''': This is the most common heat treatment encountered, because the final properties can be precisely determined by the temperature and time of the tempering. Tempering involves reheating quenched steel to a temperature below the [[eutectoid]] temperature then cooling. The elevated temperature allows very small amounts of spheroidite to form, which restores ductility, but reduces hardness. Actual temperatures and times are carefully chosen for each composition.<ref>Smith, pp. 387–388</ref>
-*'''[[Austempering]]''': The austempering process is the same as martempering, except the steel is held in the molten salt bath through the bainite transformation temperatures, and then moderately cooled. The resulting bainite steel has a greater ductility, higher impact resistance, and less distortion. The disadvantage of austempering is it can only be used on a few steels, and it requires a special salt bath.<ref>Smith, p. 391</ref>
 ==Case hardening==
 {{main|Case hardening}}
-Case hardening processes harden only the exterior of the steel part, creating a hard, wear resistant skin (the "case") but preserving a tough and ductile interior. Carbon steels are not very [[hardenability|hardenable]]; therefore wide pieces cannot be through-hardened. Alloy steels have a better hardenability, so they can through-harden and do not require case hardening. This property of carbon steel can be beneficial, because it gives the surface good wear characteristics but leaves the core tough.
+Case hardening processes harden only the exterior of the steel part, creating a hard, wear-resistant skin (the "case") but preserving a tough and ductile interior. Carbon steels are not very [[hardenability|hardenable]] meaning they can not be hardened throughout thick sections. Alloy steels have a better hardenability, so they can be through-hardened and do not require case hardening. This property of carbon steel can be beneficial, because it gives the surface good wear characteristics but leaves the core flexible and shock-absorbing.
 ==Forging temperature of steel==
-<ref name=Mat_hand>{{cite book|last=Brady|first=George S.|title=Materials Handbook|year=1997|publisher=McGraw-Hill|location=New York, NY|isbn=0-07-007084-9|edition=14th|coauthors=Clauser, Henry R. ; Vaccari A., John}}</ref>
+<ref name=Mat_hand>{{cite book |last=Brady |first=George S. |title=Materials Handbook |year=1997 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-007084-9 |edition=14th |author2=Clauser, Henry R. |author3=Vaccari A., John |url-access=registration |url=https://archive.org/details/materialshandboo14geor}}</ref>
-{| class="wikitable"
+{| class="wikitable" style=text-align:center
 |-
+! rowspan=2 | Steel type
-! Steel Type !! Maximum forging temperature (°F / °C)!! Burning temperature (°F / °C)
+! colspan=2 | Maximum forging temperature
+! colspan=2 | Burning temperature
 |-
+! (°F)
-| 1.5% carbon || 1920 / 1049 || 2080 / 1138
+! (°C)
+! (°F)
+! (°C)
 |-
-| 1.1% carbon || 1980 / 1082 || 2140 / 1171
+| style=text-align:left | 1.5% carbon || 1,920 || 1,049 || 2,080 || 1,140
 |-
-| 0.9% carbon || 2050 / 1121 || 2230 / 1221
+| style=text-align:left | 1.1% carbon || 1,980 || 1,082 || 2,140 || 1,171
 |-
-| 0.5% carbon || 2280 / 1249 || 2460 / 1349
+| style=text-align:left | 0.9% carbon || 2,050 || 1,121 || 2,230 || 1,221
 |-
-| 0.2% carbon || 2410 / 1321 || 2680 / 1471
+| style=text-align:left | 0.5% carbon || 2,280 || 1,249 || 2,460 || 1,349
 |-
-| 3.0% nickel steel || 2280 / 1249 || 2500 / 1371
+| style=text-align:left | 0.2% carbon || 2,410 || 1,321 || 2,680 || 1,471
 |-
-| 3.0% nickel–chromium steel ||  2280 / 1249 || 2500 / 1371
+| style=text-align:left | 3.0% [[nickel steel]] || 2,280 || 1,249 || 2,500 || 1,371
 |-
-| 5.0% nickel (case-hardening) steel || 2320 / 1271 || 2640 / 1449
+| style=text-align:left | 3.0% [[nickel–chromium steel]] ||  2,280 || 1,249 || 2,500 || 1,371
 |-
-| Chromium–vanadium steel || 2280 / 1249 || 2460 / 1349
+| style=text-align:left | 5.0% nickel (case-hardening) steel || 2,320 || 1,271 || 2,640 || 1,449
 |-
-| High-speed steel || 2370 / 1299 || 2520 / 1382
+| style=text-align:left | [[Chromium–vanadium steel]] || 2,280 || 1,249 || 2,460 || 1,349
 |-
-| Stainless steel || 2340 / 1282 || 2520 / 1382
+| style=text-align:left | [[High-speed steel]] || 2,370 || 1,299 || 2,520 || 1,385
 |-
-| Austenitic chromium–nickel steel || 2370 / 1299 || 2590 / 1421
+| style=text-align:left | [[Stainless steel]] || 2,340 || 1,282 || 2,520 || 1,385
 |-
-| Silico-manganese spring steel || 2280 / 1249 || 2460 / 1349
+| style=text-align:left | [[Austenitic chromium–nickel steel]] || 2,370 || 1,299 || 2,590 || 1,420
+|-
+| style=text-align:left | Silico-manganese [[spring steel]] || 2,280 || 1,249 || 2,460 || 1,350
 |}
 ==See also==
+{{div col}}
+*[[Aermet]]
 *[[Cold working]]
+*[[Eglin steel]] (a low-cost precipitation-hardened high-strength steel)
-*[[Hot working]]
-*[[Welding]]
 *[[Forging]]
+*[[Hot working]]
+*[[Maraging steel]] (precipitation-hardened high-strength steels)
+*[[Welding]] (high-strength steels)
+{{div col end}}
 ==References==
-{{reflist|2}}
+{{reflist}}
 ==Bibliography==
+{{Commons category|Carbon steel}}
-*{{Citation | last = Degarmo | first = E. Paul | last2 = Black | first2 = J T. | last3 = Kohser | first3 = Ronald A. | title = Materials and Processes in Manufacturing | publisher = Wiley | year = 2003 | edition = 9th | isbn = 0-471-65653-4 | postscript =.}}
-*{{Citation |last= Oberg |first= E. |coauthors= et al. |title= Machinery's Handbook |edition= 25th |year= 1996 |publisher= Industrial Press Inc | isbn = 0-8311-2599-3 | postscript =.}}
+*{{Citation |last1= DeGarmo |first1= E. Paul |last2= Black |first2= J T. |last3= Kohser |first3= Ronald A. |title= Materials and Processes in Manufacturing |publisher= Wiley |year= 2003 |edition= 9th |isbn= 0-471-65653-4 |postscript=.}}
-*{{Citation | last = Smith | first = William F. | last2 = Hashemi | first2 = Javad | title = Foundations of Materials Science and Engineering | edition = 4th | year = 2006 | publisher = McGraw-Hill | isbn = 0-07-295358-6 | postscript =.}}
+*{{Citation |last= Oberg |first= E. |title= Machinery's Handbook |edition= 25th |year= 1996 |publisher= Industrial Press Inc |isbn= 0-8311-2599-3 |postscript=.|display-authors=etal}}
+*{{Citation |last1= Smith |first1= William F. |last2= Hashemi |first2= Javad |title= Foundations of Materials Science and Engineering |edition= 4th |year= 2006 |publisher= McGraw-Hill |isbn= 0-07-295358-6 |postscript=.}}
+{{Authority control}}
-{{DEFAULTSORT:Carbon Steel}}
 [[Category:Steels]]
 [[Category:Metallurgical processes]]