Editing Metallurgy (section)

==Production==
In [[industrial engineering|production engineering]], metallurgy is concerned with the production of metallic components for use in consumer or [[engineering]] products. This involves production of alloys, shaping, heat treatment and surface treatment of product. The task of the metallurgist is to achieve balance between material properties, such as cost, [[weight]], [[tensile strength|strength]], [[toughness]], [[Hardness (materials science)|hardness]], [[corrosion]], [[fatigue (material)|fatigue]] resistance and performance in [[temperature]] extremes. To achieve this goal, the operating environment must be carefully considered.{{Citation needed|date=August 2022}}

Determining the hardness of the metal using the Rockwell, Vickers, and Brinell hardness scales is a commonly used practice that helps better understand the metal's elasticity and plasticity for different applications and production processes.<ref>{{Cite news |date=2017-06-14 |title=Metal Hardness Tests: Difference Between Rockwell, Brinell, and Vickers |language=en-US |work=ESI Engineering Specialties Inc. |url=https://www.esict.com/blog/rockwell-brinell-and-vickers-metal-hardness |url-status=live |access-date=2017-12-13 |archive-url=https://web.archive.org/web/20171214014727/https://www.esict.com/blog/rockwell-brinell-and-vickers-metal-hardness |archive-date=14 December 2017}}</ref> In a saltwater environment, most ferrous metals and some non-ferrous alloys corrode quickly. Metals exposed to cold or [[cryogenic]] conditions may undergo a ductile to brittle transition and lose their toughness, becoming more brittle and prone to cracking. Metals under continual cyclic loading can suffer from [[Fatigue (material)|metal fatigue]]. Metals under constant [[stress (physics)|stress]] at elevated temperatures can [[creep (deformation)|creep]].

===Metalworking processes===
{{Main|Metalworking}}
[[File:Bochumer Verein-08-50124.jpg|thumb|An open-die drop forging with two dies of an ingot, which is then further processed into a wheel]]
* [[Casting (metalworking)|Casting]] – molten metal is poured into a shaped [[Molding (process)|mold]]. Variants of casting include [[sand casting]], [[investment casting]], also called the lost wax process, [[die casting]], centrifugal casting, both vertical and horizontal, and continuous castings. Each of these forms has advantages for certain metals and applications considering factors like magnetism and corrosion.<ref>{{Cite web |title=Casting Process, Types of Casting Process, Casting Process Tips, Selecting Casting Process, Casting Process Helps |url=http://www.themetalcasting.com/casting-process.html |url-status=live |archive-url=https://web.archive.org/web/20171218093932/http://www.themetalcasting.com/casting-process.html |archive-date=18 December 2017 |access-date=2017-12-13 |website=www.themetalcasting.com |language=en}}</ref>
* [[Forging]] – a red-hot [[Billet (manufacturing)|billet]] is hammered into shape.
* [[Rolling (metalworking)|Rolling]] – a billet is passed through successively narrower rollers to create a sheet.
* [[Extrusion]] – a hot and malleable metal is forced under pressure through a [[die (manufacturing)|die]], which shapes it before it cools.
* [[Machining]] – [[Lathe (tool)|lathes]], [[milling machine]]s and [[drill]]s cut the cold metal to shape.
* [[Sintering]] – a [[powder metallurgy|powdered metal]] is heated in a non-oxidizing environment after being compressed into a die.
* [[Fabrication (metal)|Fabrication]] – sheets of metal are cut with [[guillotine]]s or [[gas welding|gas cutters]] and bent and welded into structural shape.
* [[Cladding (metalworking)|Laser cladding]] – metallic powder is blown through a movable laser beam (e.g. mounted on a NC 5-axis machine). The resulting melted metal reaches a substrate to form a melt pool. By moving the laser head, it is possible to stack the tracks and build up a three-dimensional piece.
* [[3D printing]] – Sintering or melting amorphous powder metal in a 3D space to make any object to shape.

[[Cold working|Cold-working]] processes, in which the product's shape is altered by rolling, fabrication or other processes, while the product is cold, can increase the strength of the product by a process called [[work hardening]]. Work hardening creates [[dislocation|microscopic defects]] in the metal, which resist further changes of shape.

===Heat treatment===
[[File:Heat-Treating-Furnace.jpg|thumb|A heat treating furnace at {{convert|1800|F|abbr=on}}]]
Metals can be [[heat treatment|heat-treated]] to alter the properties of strength, ductility, toughness, hardness and resistance to corrosion. Common heat treatment processes include annealing, [[precipitation strengthening]], quenching, and tempering:<ref>Arthur Reardon (2011), ''Metallurgy for the Non-Metallurgist'' (2nd ed.), ASM International, {{ISBN|978-1615038213}}</ref>
* [[Annealing (metallurgy)|Annealing]] process softens the metal by heating it and then allowing it to cool very slowly, which gets rid of stresses in the metal and makes the grain structure large and soft-edged so that, when the metal is hit or stressed it dents or perhaps bends, rather than breaking; it is also easier to sand, grind, or cut annealed metal.
* [[Quenching]] is the process of cooling metal very quickly after heating, thus "freezing" the metal's molecules in the very hard martensite form, which makes the metal harder.
* [[tempering (metallurgy)|Tempering]] relieves stresses in the metal that were caused by the hardening process; tempering makes the metal less hard while making it better able to sustain impacts without breaking.

Often, mechanical and thermal treatments are combined in what are known as thermo-mechanical treatments for better properties and more efficient processing of materials. These processes are common to high-alloy special steels, [[superalloy]]s and titanium alloys.

===Plating===
{{Main|Plating}}
[[File:Copper electroplating principle (multilingual).svg|thumb|A simplified diagram of electroplating copper on a metal]]
[[Electroplating]] is a chemical surface-treatment technique. It involves bonding a thin layer of another metal such as [[gold]], [[silver]], [[chromium]] or [[zinc]] to the surface of the product. This is done by selecting the coating material electrolyte solution, which is the material that is going to coat the workpiece (gold, silver, zinc). There needs to be two electrodes of different materials: one the same material as the coating material and one that is receiving the coating material. Two electrodes are electrically charged and the coating material is stuck to the work piece. It is used to reduce corrosion as well as to improve the product's aesthetic appearance. It is also used to make inexpensive metals look like the more expensive ones (gold, silver).<ref>{{cite web |url=http://www.explainthatstuff.com/electroplating.html |title=How electroplating works |work=Explain that Stuff |first=Chris |last=Woodford|author1-link=Chris Woodford (author) |year=2017 |access-date=20 May 2019 |archive-date=15 June 2019 |archive-url=https://web.archive.org/web/20190615083919/https://www.explainthatstuff.com/electroplating.html |url-status=live }}</ref>

=== Shot peening ===
{{main|Shot peening}}
Shot peening is a cold working process used to finish metal parts. In the process of shot peening, small round shot is blasted against the surface of the part to be finished. This process is used to prolong the product life of the part, prevent stress corrosion failures, and also prevent fatigue. The shot leaves small dimples on the surface like a peen hammer does, which cause compression stress under the dimple. As the shot media strikes the material over and over, it forms many overlapping dimples throughout the piece being treated. The compression stress in the surface of the material strengthens the part and makes it more resistant to fatigue failure, stress failures, corrosion failure, and cracking.<ref>{{cite web|url=https://www.engineeredabrasives.com/what-is-shot-peening.html|title=What is Shot Peening – How Does Shot Peening Work|website=www.engineeredabrasives.com|access-date=4 January 2019|archive-date=12 June 2018|archive-url=https://web.archive.org/web/20180612162445/https://www.engineeredabrasives.com/what-is-shot-peening.html|url-status=live}}</ref>

===Thermal spraying===
{{Main|Thermal spraying}}
Thermal spraying techniques are another popular finishing option, and often have better high temperature properties than electroplated coatings. Thermal spraying, also known as a spray welding process,<ref>{{Cite web|url=http://www.precisioncoatings.com/what-is-thermal-spray.html|title=Thermal Spray, Plasma Spray, HVOF, Flame Spray, Metalizing & Thermal Spray Coating|location=Saint Paul, MN|website=www.precisioncoatings.com|access-date=2017-12-13|archive-date=14 August 2022|archive-url=https://web.archive.org/web/20220814091513/https://www.precisioncoatings.com/what-is-thermal-spray/|url-status=live}}</ref> is an industrial coating process that consists of a heat source (flame or other) and a coating material that can be in a powder or wire form, which is melted then sprayed on the surface of the material being treated at a high velocity. The spray treating process is known by many different names such as HVOF (High Velocity Oxygen Fuel), plasma spray, flame spray, arc spray and metalizing.

=== Electroless deposition ===
{{Main|Electroless deposition}}
Electroless deposition (ED) or electroless plating is defined as the [[Autocatalysis|autocatalytic process]] through which metals and metal alloys are deposited onto nonconductive surfaces. These nonconductive surfaces include plastics, ceramics, and glass etc., which can then become decorative, anti-corrosive, and conductive depending on their final functions. Electroless deposition is a chemical processes that create [[metal]] coatings on various materials by [[Autocatalysis|autocatalytic]] [[Redox reaction|chemical reduction]] of metal [[cation]]s in a liquid bath.