Product Code Database
Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of Chemical element, their inter-metallic compounds, and their mixtures, which are known as .
Metallurgy encompasses both the science and the technology of metals, including the production of and the engineering of metal components used in products for both consumers and manufacturers. Metallurgy is distinct from the craft of metalworking. Metalworking relies on metallurgy in a similar manner to how medicine relies on medical science for technical advancement. A specialist practitioner of metallurgy is known as a metallurgist.
The science of metallurgy is further subdivided into two broad categories: chemical metallurgy and physical metallurgy. Chemical metallurgy is chiefly concerned with the reduction and oxidation of metals, and the chemical performance of metals. Subjects of study in chemical metallurgy include mineral processing, the extraction of metals, thermodynamics, electrochemistry, and chemical degradation (corrosion). (1990). 9780408053693 ISBN 9780408053693 In contrast, physical metallurgy focuses on the mechanical properties of metals, the physical properties of metals, and the physical performance of metals. Topics studied in physical metallurgy include crystallography, material characterization, mechanical metallurgy, Phase transition, and failure mechanisms.
Historically, metallurgy has predominately focused on the production of metals. Metal production begins with the processing of to extract the metal, and includes the mixture of metals to make . Metal alloys are often a blend of at least two different metallic elements. However, non-metallic elements are often added to alloys in order to achieve properties suitable for an application. The study of metal production is subdivided into ferrous metallurgy (also known as black metallurgy) and non-ferrous metallurgy, also known as colored metallurgy.
Ferrous metallurgy involves processes and alloys based on iron, while non-ferrous metallurgy involves processes and alloys based on other metals. The production of ferrous metals accounts for 95% of world metal production. "Металлургия" . in The Great Soviet Encyclopedia. 1979.
Modern metallurgists work in both emerging and traditional areas as part of an interdisciplinary team alongside material scientists and other engineers. Some traditional areas include mineral processing, metal production, heat treatment, failure analysis, and the joining of metals (including welding, brazing, and soldering). Emerging areas for metallurgists include nanotechnology, superconductors, composites, Biomaterial, electronic materials (semiconductors) and surface engineering.
In the late 19th century, metallurgy's definition was extended to the more general scientific study of metals, alloys, and related processes. In English language, the pronunciation is the more common one in the United Kingdom. The pronunciation is the more common one in the United States and is the first-listed variant in various American dictionaries, including Merriam-Webster Collegiate and American Heritage.
The earliest archaeological support of smelting (hot metallurgy) in Eurasia is found in the Balkans and Carpathian Mountains, as evidenced by findings of objects made by metal casting and smelting dated to around with the invention of copper metallurgy. Certain metals, such as tin, lead, and copper can be recovered from their ores by simply heating the rocks in a comparatively moderate-temperature fire or blast furnace in a process known as smelting. The first evidence of copper smelting, dating from the has been found at archaeological sites in Majdanpek, Jarmovac, and Pločnik, in present-day Serbia.
The site of Pločnik has produced a smelted copper axe dating from belonging to the Vinča culture. The Balkans and adjacent Pannonian Basin region were the location of major Chalcolithic cultures including Vinča, Varna culture, Karanovo culture, Gumelnița and Hamangia culture, which are often grouped together under the name of 'Old Europe'. With the Carpatho-Balkan region described as the 'earliest metallurgical province in Eurasia',
The earliest documented use of lead (possibly native or smelted) in the Near East dates from the is from the late Neolithic settlements of Yarim Tepe and Arpachiyah in Iraq. The artifacts suggest that lead smelting may have predated copper smelting. Metallurgy of lead has also been found in the Balkans during the same period.
Copper smelting is documented at sites in Anatolia and at the site of Tal-i Iblis in southeastern Iran from
Copper smelting is first documented in the Nile Delta region of northern Egypt in associated with the Maadi culture. This represents the earliest evidence for smelting in Africa.
The Varna Necropolis, Bulgaria, is a burial site located in the western industrial zone of Varna, approximately 4 km from the city centre, internationally considered one of the key archaeological sites in world prehistory. The oldest gold treasure in the world, dating from was discovered at Varna Necropolis.
In approximately ancient iron smelting sites existed in Tamil Nadu.
In the Near East, about it was discovered that by combining copper and tin, a superior metal could be made, an alloy called bronze. This represented a major technological shift known as the Bronze Age.
The extraction of iron from its ore into a workable metal is much more difficult than for copper or tin. The process appears to have been invented by the Hittites in about beginning the Iron Age. The secret of extracting and working iron was a key factor in the success of the Philistines.
Historical developments in ferrous metallurgy can be found in a wide variety of past cultures and civilizations. This includes the ancient and medieval kingdoms and empires of the Middle East and Near East, ancient Iran, ancient Egypt, ancient Nubia, and Anatolia in present-day Turkey, Nok culture, Carthage, the Celts, Greeks and ancient Rome of ancient Europe, medieval Europe, ancient and medieval China, ancient and medieval India, ancient and medieval Japan, amongst others.
A 16th century book by Georg Agricola, De re metallica, describes the highly developed and complex processes of mining metal ores, metal extraction, and metallurgy of the time. Agricola has been described as the "father of metallurgy".
After mining, large pieces of the ore feed are broken through crushing or grinding in order to obtain particles small enough, where each particle is either mostly valuable or mostly waste. Concentrating the particles of value in a form supporting separation enables the desired metal to be removed from waste products.
Mining may not be necessary, if the ore body and physical environment are conducive to In-situ leaching. Leaching dissolves minerals in an ore body and results in an enriched solution. The solution is collected and processed to extract valuable metals. Ore bodies often contain more than one valuable metal.
Tailings of a previous process may be used as a feed in another process to extract a secondary product from the original ore. Additionally, a concentrate may contain more than one valuable metal. That concentrate would then be processed to separate the valuable metals into individual constituents.
Other engineering include aluminium, chromium, copper, magnesium, nickel, titanium, zinc, and silicon. These metals are most often used as alloys with the noted exception of silicon, which is not a metal. Other forms include:
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. 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 metal fatigue. Metals under constant stress at elevated temperatures can creep.
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 in the metal, which resist further changes of shape.
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, and titanium alloys.
In metallography, an alloy of interest is ground flat and polished to a mirror finish. The sample can then be etched to reveal the microstructure and macrostructure of the metal. The sample is then examined in an optical or electron microscope, and the image contrast provides details on the composition, mechanical properties, and processing history.
Crystallography, often using diffraction of or , is another valuable tool available to the modern metallurgist. Crystallography allows identification of unknown materials and reveals the crystal structure of the sample. Quantitative crystallography can be used to calculate the amount of phases present as well as the degree of strain to which a sample has been subjected.
Current advanced characterization techniques, which are used frequently in this field are: Scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD) and Atom probe (APT).
(2016). 9783867570107, Leidorf. ISBN 9783867570107 its scale and technical quality of metal production in the totally overshadowed that of any other contemporary production centre.
(2025). 9780226305110, University of Chicago Press. ISBN 9780226305110 The gold piece dating from found in 2019 in Durankulak, near Varna is another important example. Other signs of early metals are found from the in Palmela, Portugal, Los Millares, Spain, and Stonehenge, United Kingdom. The precise beginnings, however, have not be clearly ascertained and new discoveries are both continuous and ongoing.
W. Keller (1963). 034000312X, Hodder and Stoughton. 034000312X
Extraction
Extractive metallurgy is the practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form. In order to convert a metal oxide or sulfide to a purer metal, the ore must be redox physically, chemistry, or electrolyte. Extractive are interested in three primary streams: feed, concentrate (metal oxide/sulphide) and tailings (waste).
Metal and its alloys
Much effort has been placed on understanding iron–carbon alloy system, which includes and . carbon steel (those that contain essentially only carbon as an alloying element) are used in low-cost, high-strength applications, where neither weight nor corrosion are a major concern. Cast irons, including ductile iron, are also part of the iron-carbon system. Iron-Manganese-Chromium alloys (Hadfield-type steels) are also used in non-magnetic applications such as directional drilling.
Production
In 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, toughness, hardness, corrosion, fatigue resistance and performance in temperature extremes. To achieve this goal, the operating environment must be carefully considered.
Metalworking processes
Heat treatment
Metals can be heat treatment to alter the properties of strength, ductility, toughness, hardness and resistance to corrosion. Common heat treatment processes include annealing, precipitation strengthening, quenching, and tempering:
Plating
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).
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.
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, is an industrial coating process that consists of a heat source (flame or other) and a coating material; the coating can be in a powder or wire form, either of which is melted and then sprayed at a high velocity onto the surface of the material being treated. 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
Electroless deposition (ED) or electroless plating is defined as the Autocatalysis, through which metals and metal alloys are deposited onto nonconductive surfaces. These nonconductive surfaces include plastics, ceramics, glass, etc., which can then become decorative, anti-corrosive, and conductive, depending on the method of deposition and the designed use. Electroless deposition is a chemical processes that create metal coatings on various materials by Autocatalysis Redox reaction of metal in a liquid bath.
Characterization
study the microscopic and macroscopic structure of metals using metallography, a technique invented by Henry Clifton Sorby.
See also
Footnotes
External links
|
|
