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Leaded Copper
Leaded copper is a metal alloy of copper with lead. A small amount of lead makes the copper easier to machine. Alloys with a larger amount of lead are used for bearings. Brass and bronze alloys of copper may have lead added and are then also sometimes referred to as leaded copper alloys.Welter (2014) Leaded copper and its alloys have been used since ancient times. Applications Leaded copper alloys are used to make electrical connectors and mechanical bearings, especially in the automotive industry where high performance and reliability are required. Mechanical bearings can have high lead content. Such high lead content alloys are unsuitable for welding or brazing. Machined alloys Alloys with around 2-4% lead are used for machined copper applications, where the lead content lubricates the copper and makes it easier to machine. These include high-quality electrical connectors where a high current capacity and low electrical resistance are required. Such connectors are used in indust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, opacity, and luster, but may have properties that differ from those of the pure metals, such as increased strength or hardness. In some cases, an alloy may reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength. Alloys are defined by a metallic bonding character. The alloy constituents are usually measured by mass percentage for practical applications, and in atomic fraction for basic science studies. Alloys are usually classified as substitutional or interstitial alloys, depending on the atomic arrangement that forms the alloy. They can be further classified as homogene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing (mechanical)
A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may ''prevent'' a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts. Rotary bearings hold rotating components such as shafts or axles within mechanical systems, and transfer axial and radial loads from the source of the load to the structure supporting it. The simplest form of bearing, the ''plain bearing'', consists of a shaft rotating in a hole. Lubrication is used to reduce friction. In the ''ball bearing'' and ''roller bearing'', to reduce sliding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brass
Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different mechanical, electrical, and chemical properties. It is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure. Brass is similar to bronze, another copper alloy, that uses tin instead of zinc. Both bronze and brass may include small proportions of a range of other elements including arsenic (As), lead (Pb), phosphorus (P), aluminium (Al), manganese (Mn), and silicon (Si). Historically, the distinction between the two alloys has been less consistent and clear, and modern practice in museums and archaeology increasingly avoids both terms for historical objects in favor of the more general "copper alloy". Brass has long been a popular material for decoration due to its bright, gold-like appearance; being used for drawer pulls and doorknobs. It has also been widely used to make utensils because of its low melting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronze
Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals, such as phosphorus, or metalloids such as arsenic or silicon. These additions produce a range of alloys that may be harder than copper alone, or have other useful properties, such as ultimate tensile strength, strength, ductility, or machinability. The three-age system, archaeological period in which bronze was the hardest metal in widespread use is known as the Bronze Age. The beginning of the Bronze Age in western Eurasia and India is conventionally dated to the mid-4th millennium BCE (~3500 BCE), and to the early 2nd millennium BCE in China; elsewhere it gradually spread across regions. The Bronze Age was followed by the Iron Age starting from about 1300 BCE and reaching most of Eurasia by about 500 BCE, although bronze continued to be much more widely used than it is in mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casting
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a ''casting'', which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various ''time setting'' materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Heavy equipment like machine tool beds, ships' propellers, etc. can be cast easily in the required size, rather than fabricating by joining several small pieces. Casting is a 7,000-year-old process. The oldest surviving casting is a copper frog from 3200 BC. History Throughout history, metal casting has been used to make tools, weapons, and religious objects. Metal casting history and de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sintering
Clinker nodules produced by sintering Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plastics, and other materials. The atoms in the materials diffuse across the boundaries of the particles, fusing the particles together and creating one solid piece. Because the sintering temperature does not have to reach the melting point of the material, sintering is often chosen as the shaping process for materials with extremely high melting points such as tungsten and molybdenum. The study of sintering in metallurgical powder-related processes is known as powder metallurgy. An example of sintering can be observed when ice cubes in a glass of water adhere to each other, which is driven by the temperature difference between the water and the ice. Examples of pressure-driven sintering are the compact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egyptian Faience
Egyptian faience is a sintered-quartz ceramic material from Ancient Egypt. The sintering process "covered he materialwith a true vitreous coating" as the quartz underwent vitrification, creating a bright lustre of various colours "usually in a transparent blue or green isotropic glass". Its name in the Ancient Egyptian language was , and modern archeological terms for it include sintered quartz, glazed frit, and glazed composition. is distinct from the crystalline pigment Egyptian blue, for which it has sometimes incorrectly been used as a synonym. It is not faience in the usual sense of tin-glazed pottery, and is different from the enormous range of clay-based Ancient Egyptian pottery, from which utilitarian vessels were made. It is similar to later Islamic stonepaste (or "fritware") from the Middle East, although that generally includes more clay. Egyptian faience is considerably more porous than glass proper. It can be cast in molds to create small vessels, jewelry and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kao Gong Ji
The ''Kao Gong ji'' (考工记), translated variously as the ''Record of Trades'', ''Records of Examination of Craftsman'', ''Book of Diverse Crafts'' or ''Artificers' Record'', is a classic work on science and technology in Ancient China, compiled sometime between the fifth and third centuries BCE and later included in the Zhou Li. The study of ''Kao Gong Ji'', ''Kao Gong Ji Jie'', was published ca 1235 by Lin Xiyi 林希逸. It was followed by Dai Zhen (''Kaogongji tu'', 1746) and Cheng Yaotian 程瑶田 (''Kaogongji chuangwu xiaoji'', ca 1805). It has been suggested that "The Kaogong ji may have been written by an administrator to assure the emperor that everything was under control. It is part of a manual for how to run the empire". The ''Kao Gong Ji'' is the oldest known technical encyclopedia. The book includes recipes for metal-making described as "enigmatic". In 2022 researchers identified ''jin'' and ''xi'', key components for making bronze for 100 years thought to have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Alloys
Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. The best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead. Both of these are imprecise terms, having both been commonly referred to as lattens in the past. Today the term ''copper alloy'' tends to be substituted, especially by museums. Composition The similarity in external appearance of the various alloys, along with the different combinations of elements used when making each alloy, can lead to confusion when categorizing the different compositions. There are as many as 400 different copper and copper alloy compositions loosely grouped into the categories: copper, high copper alloy, brasses, bronzes, copper nickels, copper–nickel–zinc (nickel silver), leaded copper, and special alloys. The following table lists the principal alloying element for four of the more common types used in modern i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
