Ingot Structure
The ingot is a piece of a relatively pure material, usually steel, that has been cast into a form that is suitable for further processing[1]. Ingots typically require a second forming process for creating a helpful end product, including cold / hot operation, cutting or milling. The use of precious metal ingots can either be used as currency (in the form or without being handled in any way) or as a reserve currency, such as the gold bars. Ingots are manufactured from precious metal and semiconductors and are made in bulk form.
Pouring Smelted Gold into an ingot at the La Luz Gold Mine in Siuna, Nicaragua about 1959.
Types
Ingots are usually made of pure or alloy material, they are heated past the point where they melt and cast by means of a chilling process into a bar or block.
A special case is made by pulling from a molten mould polycrystalline and individual crystal ingots.
Single crystal
Products (Crystal Growing) are produced with single crystal ingots (so-called "boules") using methods such as Czokralski or Bridgeman.
Boules can be inorganic compounds for use in the industries and jewelry (e.g. synthetic rubies and saphire), or semi-conductive ones (e.g. digital Chips, cells of photovoltaic)
Copper alloys
The brass and bronze ingot manufacturing industries started in the United States at the start of the 19th century. Based on the fact that the British ordered that all copper ores be sent to the UK for processing, the copper-based alloy orange ingots weighed around 20 pound. By 1750, the US brass industry expanded to be the number one producers.
Manufacture
The bark is formed by freezing in a mold a molten liquid (the melt). There are several goals in the processing of ingots. Firstly, it is designed to fully stabilize and shape a suitable grain structure required for further processing since it tracks the physical properties of the material through its freezing melt structure. Second, the mold's shape and scale are designed to make it simple to handle and process downstream. Eventually, it is meant to reduce waste of melt and allow the ingot to be expelled because the loss of melt and ingot raises the production costs of finished products.
Crystalline structure of mold cast ingot
There are a number of models for the mold that can be used to satisfy the physical properties of the liquid melt and the phase of solidification. Molds can be fluted or walled on top, horizontally or bottom-up pouring. Due to a larger contact area, the fluted model increases heat transfer. Solid "massive" molds or sand casts (e.g. for pig iron) or water-cooled shells may be used depending on the requirements of heat transfer. Ingot molds have been tapered so that cracks are prevented by irregular refrigeration. The creation of cracks or voids takes place as the fluid transition to solids varies in the density of a continuous material mass. Such ingot deficiencies might render the cast ingot unusable and might have to be replenished, reused or discarded.
The physical structure of a crystalline substance is largely determined by the cooling process and molten metal precipitation. The metal in contact with the ingot walls cools quickly and forms, depending on the refraction fluid and the mold cooling rate, either a columnary structure or, possibly, a "chill zone" for equiaxed dendrite.
Teeming ingots at a steel mill
Differential pressure effects cause the top of the fluid to decrease as the liquid cools within the mold and the surface of the curved surface on the top of the mold to be machined from the lingoid. The mold cooling effect produces a forward solidification facing which has several linked zones, a solid area near the wall draws energy from the solidifying melt, a "mushy" zone for alloys which is the outcome of the phase diagram of solid-liquid equilibrium regions and a liquid region. In the solidification area, the frontal advancement level controls the time dendrites or nuclei must develop. Through changing the heat transport properties in the mould or by modifying the compositions of the liquid melt alloys, the width of an alloy can be controlled.
There are also continuous casting techniques for the production of the ingot, which include the constant removal of cooled solid material and an introduction of molten fluid in the casting process as a stationary front of solidification.
Approximately 70% of aluminum ingots are cast in the United States by direct chilling, thereby reducing breakage. A cumulative 5% of ingots must be scrapped due to cracks and butt distortions caused by stress.
