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Gilding Metal
Gilding metal is a form of brass (an alloy of copper and zinc) with a much higher copper content than zinc content. Exact figures range from 95% copper and 5% zinc to “8 parts copper to 1 of zinc” (11% zinc) in British Army Dress Regulations. Gilding metal is used for various purposes, including the jackets of bullets, driving bands on some artillery shells, as well as enameled badges and other jewellery. The sheet is widely used for craft metalworking by hammer working. It is also used particularly as a lower-cost training material for silversmiths. Starting in 1944, shell casings made of gilding metal were melted down by the United States Mint to be made into pennies. These pennies replaced the less popular steel cent of 1943, and the pennies of this composition were produced until 1946. Gilding metal was also used for the "bronze" Olympic medal at the 2020 Summer Olympics The , officially the and also known as , was an international multi-sport event held from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilding Metal Jug
Gilding is a decorative technique for applying a very thin coating of gold over solid surfaces such as metal (most common), wood, porcelain, or stone. A gilded object is also described as "gilt". Where metal is gilded, the metal below was traditionally silver in the West, to make silver-gilt (or ''vermeil'') objects, but gilt-bronze is commonly used in China, and also called ormolu if it is Western. Methods of gilding include hand application and gluing, typically of gold leaf, chemical gilding, and electroplating, the last also called gold plating. Parcel-gilt (partial gilt) objects are only gilded over part of their surfaces. This may mean that all of the inside, and none of the outside, of a chalice or similar vessel is gilded, or that patterns or images are made up by using a combination of gilt and ungilted areas. Gilding gives an object a gold appearance at a fraction of the cost of creating a solid gold object. In addition, a solid gold piece would often be too soft or t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silversmith
A silversmith is a metalworker who crafts objects from silver. The terms ''silversmith'' and ''goldsmith'' are not exactly synonyms as the techniques, training, history, and guilds are or were largely the same but the end product may vary greatly as may the scale of objects created. History In the ancient Near East the value of silver to gold was lower, allowing a silversmith to produce objects and store these as stock. Ogden states that according to an edict written by Diocletian in 301 A.D., a silversmith was able to charge 75, 100, 150, 200, 250, or 300 ''denarii'' for material produce (per Roman pound). At that time, guilds of silversmiths formed to arbitrate disputes, protect its members' welfare and educate the public of the trade. Silversmiths in medieval Europe and England formed guilds and transmitted their tools and techniques to new generations via the apprentice tradition. Silver working guilds often maintained consistency and upheld standards at the expense of in ... [...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] |
Pinchbeck Alloy
Pinchbeck is a form of brass, an alloy of copper and zinc mixed in proportions so that it closely resembles gold in appearance. It was invented in the early 18th century by Christopher Pinchbeck (died 1732), a London clock- and watch-maker. Since gold was only sold in 18-carat quality at that time, the development of pinchbeck allowed ordinary people to buy gold 'effect' jewellery on a budget. The inventor allegedly made pinchbeck jewellery clearly labelled as such. Pinchbeck jewellery was used in places like stagecoaches where there was a risk of theft. The original Pinchbeck was made by Christopher Pinchbeck and his descendants until the 1830s. Later dishonest jewellers passed pinchbeck off as gold; over the years the name came to mean a cheap and tawdry imitation of gold. Today, depending on the dealer, "Pinchbeck" can mean original Pinchbeck or any gilt metal. Pinchbeck fell out of use in the second half of the 19th century, being replaced by low-carat gold which had been l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crack (fracture)
Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displacement develops perpendicular to the surface, it is called a normal tensile crack or simply a crack; if a displacement develops tangentially, it is called a shear crack, slip band or dislocation. Brittle fractures occur with no apparent deformation before fracture. Ductile fractures occur after visible deformation. Fracture strength, or breaking strength, is the stress when a specimen fails or fractures. The detailed understanding of how a fracture occurs and develops in materials is the object of fracture mechanics. Strength Fracture strength, also known as breaking strength, is the stress at which a specimen fails via fracture. This is usually determined for a given specimen by a tensile test, which charts the stress–strain cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annealing (metallurgy)
In metallurgy and materials science, annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material above its recrystallization temperature, maintaining a suitable temperature for an appropriate amount of time and then cooling. In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to a change in ductility and hardness. As the material cools it recrystallizes. For many alloys, including carbon steel, the crystal grain size and phase composition, which ultimately determine the material properties, are dependent on the heating rate and cooling rate. Hot working or cold working after the annealing process alters the metal structure, so further heat treatments may be used to achieve the properties required. With knowledge of the composition and phase diagram, heat treatment can be used to ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2020 Summer Olympics
The , officially the and also known as , was an international multi-sport event held from 23 July to 8 August 2021 in Tokyo, Japan, with some preliminary events that began on 21 July. Tokyo was selected as the host city during the 125th IOC Session in Buenos Aires, Argentina, on 7 September 2013. The Games were originally scheduled to take place from 24 July to 9 August 2020, but due to the global COVID-19 pandemic, on 24 March 2020, the event was postponed to 2021, the first such instance in the history of the Olympic Games (previous games had been cancelled but not rescheduled). However, the event retained the ''Tokyo 2020'' branding for marketing purpose.Multiple sources: * * * It was largely held behind closed doors with no public spectators permitted due to the declaration of a state of emergency in the Greater Tokyo Area in response to the pandemic, the first and so far only Olympic Games to be held without official spectators. The Games were the mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olympic Medal
An Olympic medal is awarded to successful competitors at one of the Olympic Games. There are three classes of medal to be won: gold, silver, and bronze, awarded to first, second, and third place, respectively. The granting of awards is laid out in detail in the Olympic protocols. Medal designs have varied considerably since the Games in 1896, particularly in the size of the medals for the Summer Olympic Games. The design selected for the 1928 Games remained for many years, until its replacement at the 2004 Games in Athens as the result of controversy surrounding the use of the Roman Colosseum rather than a building representing Greek roots. The medals of the Winter Olympic Games never had a common design, but regularly feature snowflakes and the event where the medal has been won. In addition to generally supporting their Olympic athletes, some countries provide sums of money and gifts to medal winners, depending on the classes and number of medals won. Introduction and ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1943 Steel Cent
1943 steel cents are U.S. one-cent coins that were struck in steel due to wartime shortages of copper. The Philadelphia, Denver, and San Francisco mints each produced these 1943 Lincoln cents. The unique composition of the coin ( low-grade steel coated with zinc, instead of the previously 95%-copper-based bronze composition) has led to various nicknames, such as ''wartime cent'', ''steel war penny'', ''zinc cent'' and ''steelie''. The 1943 steel cent features the same Victor David Brenner design for the Lincoln cent which had been in use since 1909. History Due to wartime needs of copper for use in ammunition and other military equipment during World War II, the United States Mint researched various ways to limit dependence and meet conservation goals on copper usage. After trying out several substitutes (ranging from other metals to plastics) to replace the then-standard bronze alloy, the one-cent coin was minted in zinc-coated steel. This alloy caused the new coins to be m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penny (United States Coin)
The cent, the United States one-cent coin (symbol: ¢), often called the "penny", is a unit of currency equaling one one-hundredth of a United States dollar. It has been the lowest face-value physical unit of U.S. currency since the abolition of the half-cent in 1857 (the abstract mill, which has never been minted, equal to a tenth of a cent, continues to see limited use in the fields of taxation and finance). The first U.S. cent was produced in 1787, and the cent has been issued primarily as a copper or copper-plated coin throughout its history. The penny is issued in its current form as the Lincoln cent, with its obverse featuring the profile of President Abraham Lincoln since 1909, the centennial of his birth. From 1959 (the sesquicentennial of Lincoln's birth) to 2008, the reverse featured the Lincoln Memorial. Four different reverse designs in 2009 honored Lincoln's 200th birthday and a new, "permanent" reverse – the Union Shield – was introduced in 2010. The coin is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Mint
The United States Mint is a bureau of the Department of the Treasury responsible for producing coinage for the United States to conduct its trade and commerce, as well as controlling the movement of bullion. It does not produce paper money; that responsibility belongs to the Bureau of Engraving and Printing. The first United States Mint was created in Philadelphia in 1792, and soon joined by other centers, whose coins were identified by their own mint marks. There are currently four active coin-producing mints: Philadelphia, Denver, San Francisco, and West Point. History The Massachusetts Bay Colony established a mint in Boston in 1652. John Hull was Treasurer and mintmaster; Hull's partner at the "Hull Mint" was Robert Sanderson. The historical marker reads: The first authorization for the establishment of a mint in the United States was in a resolution of the Congress of the Confederation of February 21, 1782, and the first general-circulation coin of the United States ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shell Casings
A cartridge or a round is a type of pre-assembled firearm ammunition packaging a projectile (bullet, shot (pellet), shot, or shotgun slug, slug), a propellant substance (usually either smokeless powder or black powder) and an ignition device (primer (firearm), primer) within a metallic cartridge, metallic, paper cartridge, paper, or polymer-cased ammunition, plastic case that is precisely made to fit within the gun barrel, barrel chamber (firearms), chamber of a breechloading gun, for the practical purpose of convenient transportation and handling during shooting. Although in popular usage the term "bullet" is often informally used to refer to a complete cartridge, it is correctly used only to refer to the projectile. Cartridges can be categorized by the type of their primers – a small charge of an shock sensitivity, impact- or electronic firing, electric-sensitive chemical mixture that is located: at the center of the #Case, case head (centerfire); inside the rim (firearms), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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