Ingot
A ingot is a definite mass of a metal run in a solid block. This metal is then ready to be transformed.
One usually speaks about ingot for the noble metals, the term then evokes a small pure metal bar: gold, money, platinum… They are used at the central banks of the countries with thésauriser of the reserves as funds. For example, of the ingots of one ounce gold 31,103 G weigh.
But the ingot term also indicates industrial metal castings being able to reach several tons. Metals can also be run in other form, in various moulds of form (bars, complex forms).
Within the industrial framework, the ingot undergoes transformations: Rolling to thin it and it widen (or to lengthen it), Heat treatment (Hardening, Reheated), cutting, surface treatment…
Typical structure Crystal line
An ingot results from a casting in a mould overall parallelipipedic; in general, it is about a pyramid truncated at rectangular base in order to be able to unmould the ingot. Cooling is done by outside; consequently, it creates for itself a Gradient Température: the heart of the liquid is hotter than the edges. The Solidification thus starts with the edges and ends in the center.
It in general results from it a typical structure in three “layers”: “column-like” structure known as at the edge, followed by a dendritic structure, then in the middle of a structure équiaxe.
The decreasing metal of volume during solidification, the top of the ingot, which is with the free air, in general presents a hollow called “Retassure”. If metal were badly degassed, it will present on the surface “splits” (kind of furrows resembling cracks) and Pore S inside.
However, this structure is not systematic; that depends largely the speed of solidification, on the direction of solidification (one can voluntarily isolate certain parts of the mould to have a directed solidification) and possible addition of Flocculating.
See also: Dendrite (solidification)
Simple: Ingot
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