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In metallurgy, peening is the process of working a metal's surface to improve its material properties, usually by mechanical means, such as hammer blows, by blasting with shot (shot peening), focusing light (laser peening), or in recent years, with water column impacts (water jet peening) and cavitation jets (cavitation peening). [1]
A kinebar is a gold bar that has a diffractive optically variable image device (similar to a security hologram) embossed into the surface of the gold. The device used is a "Kinegram" made by OVD Kinegram AG (Switzerland). [1]
Image of surface reconstruction on a clean Au() surface, as visualized using scanning tunneling microscopy.The individual atoms composing the material are visible. Surface reconstruction causes the surface atoms to deviate from the bulk crystal structure, and arrange in columns several atoms wide with regularly-spaced pits between them.
A ball-peen or ball pein hammer, also known as a machinist's hammer, [1] is a type of peening hammer used in metalworking. It has two heads, one flat and the other, called the peen, rounded. It is distinguished from a cross-peen hammer, diagonal-peen hammer, point-peen hammer, or chisel-peen hammer by having a hemispherical peen.
Because peening typically produces larger surface features than sand-blasting, the resulting effect is more pronounced. Shot peening and abrasive blasting can apply materials on metal surfaces. When the shot or grit particles are blasted through a powder or liquid containing the desired surface coating, the impact plates or coats the workpiece ...
Laser peening (LP), or laser shock peening (LSP), is a surface engineering process used to impart beneficial residual stresses in materials. The deep, high-magnitude compressive residual stresses induced by laser peening increase the resistance of materials to surface-related failures, such as fatigue, fretting fatigue, and stress corrosion cracking.
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The proportions of silver and gold can vary widely. Doré bars weigh as much as 25 kg. During the 19th century gold rushes, gold nuggets and dust were melted into crude gold bars mistakenly called "bullion" by miners. They were, more accurately, doré bars with higher contents of silver and other adulterants than the mints would accept.