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This article is about factories that make castings of metal. Casting is a manufacturing process by which a liquid material is (usually poured into a mold which The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across For foundries related to the electronics industry, see foundry (electronics). Electronics refers to the flow of charge (moving Electrons through Nonmetal conductors (mainly Semiconductors, whereas electrical In the Microelectronics industry a semiconductor fabrication plant (commonly called a fab) is a factory where devices such as Integrated circuits are manufactured For other uses, see Foundry (disambiguation).
Worker in a Foundry.
Worker in a Foundry.

A foundry is a factory which produces metal castings from either ferrous or non-ferrous alloys. A factory (previously manufactory) or manufacturing plant is an industrial Building where workers manufacture goods The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across Casting is a manufacturing process by which a liquid material is (usually poured into a mold which Ferrous, in the chemical science realm indicates a bivalent iron compound (+2 oxidation state (as opposed to Ferric, which indicates a trivalent iron compound (+3 oxidation Ferrous, in the chemical science realm indicates a bivalent iron compound (+2 oxidation state (as opposed to Ferric, which indicates a trivalent iron compound (+3 oxidation Metals are turned into parts by melting the metal into a liquid, pouring the metal in a mold, and then removing the mold material or casting. The most common metal alloys produced are aluminum and cast iron. WikipediaNaming Cast iron usually refers to grey cast iron, but identifies a large group of Ferrous Alloys which solidify with a Eutectic. However, other metals, such as steel, magnesium, copper, tin, and zinc, can be processed. Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30

The people who work in the foundry making molds and pouring castings traditionally worked moving sand extensively, and thus were affectionately called sandrats.

Contents

Melting

Melting is performed in a furnace. A furnace is a device used for Heating The name derives from Latin fornax, Oven. Virgin material, external scrap, internal scrap, and alloying elements are used to charge the furnace. Virgin material refers to commercially pure forms of the primary metal used to form a particular alloy. Alloying elements are either pure forms of an alloying element, like electrolytic nickel, or alloys of limited composition, such as ferroalloys or master alloys. External scrap is material from other forming processes such as punching, forging, or machining. Internal scrap consists of the gates, risers, or defective castings.

The process includes melting the charge, refining the melt, adjusting the melt chemistry and tapping into a transport vessel. Refining is done to remove deleterious gases and elements from the molten metal. Material is added during the melting process to bring the final chemistry within a specific range specified by industry and/or internal standards. During the tap, final chemistry adjustments are made.

Furnace

Main article: furnace

Furnaces are refractory lined vessels that contain the material to be melted and provide the energy to melt it. A furnace is a device used for Heating The name derives from Latin fornax, Oven. Modern furnace types include electric arc furnaces (EAF), induction furnaces, cupolas, reverberatory, and crucible furnaces. An electric arc furnace (EAF is a Furnace that heats charged material by means of an Electric arc. An induction furnace is an electrical Furnace in which the heat is applied by Induction heating of a conductive medium (usually a Metal) in a Crucible A reverberatory furnace is a metallurgical or process Furnace that isolates the material being processed from contact with the Fuel, but not from contact Furnace choice is dependent on the alloy system and quantities produced. For ferrous materials, EAFs, cupolas, and induction furnaces are commonly used. Reverberatory and crucible furnaces are common for producing aluminum castings.

Furnace design is a complex process, and the design can be optimized based on multiple factors. Furnaces in foundries can be any size, ranging from mere ounces to hundreds of tons, and they are designed according to the type of metals that are to be melted. Also, furnaces must be designed around the fuel being used to produce the desired temperature. For low temperature melting point alloys, such as zinc or tin, melting furnaces may reach around 327 Celsius. Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30 Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 Electricity, propane, or natural gas are usually used for these temperatures. For high melting point alloys such as steel or nickel based alloys, the furnace must be designed for temperatures over 3600 Celsius. The fuel used to reach these high temperatures can be electricity or coke. Coke is a solid Carbonaceous material derived from Destructive distillation of low-ash low-sulfur Bituminous coal.

The majority of foundries specialize in a particular metal and have furnaces dedicated to these metals. For example, an iron foundry (for cast iron) may use a cupola, induction furnace, or EAF, while a steel foundry will use an EAF or induction furnace. Cast iron usually refers to grey cast iron, but identifies a large group of Ferrous Alloys which solidify with a Eutectic. Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 An electric arc furnace (EAF is a Furnace that heats charged material by means of an Electric arc. An induction furnace is an electrical Furnace in which the heat is applied by Induction heating of a conductive medium (usually a Metal) in a Crucible Bronze or brass foundries use crucible furnaces or induction furnaces. Bronze is any of a broad range of Copper alloys, usually with Tin as the main additive but sometimes with other elements such as Phosphorus Brass is any Alloy of Copper and Zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties An induction furnace is an electrical Furnace in which the heat is applied by Induction heating of a conductive medium (usually a Metal) in a Crucible Most aluminum foundries use either an electric resistance or gas heated crucible furnaces or reverberatory furnaces. WikipediaNaming A crucible is a cup-shaped piece of laboratory object Laboratory equipment used to contain Chemical compounds when heating them to very high Temperatures

Molding

Prior to pouring a casting, the foundry produces a mold. Casting is a manufacturing process by which a liquid material is (usually poured into a mold which The molds are constructed by several different processes dependent upon the type of foundry, metal to be poured, quantity of parts to be produced, size of the casting and complexity of the casting. Casting is a manufacturing process by which a liquid material is (usually poured into a mold which Casting is a manufacturing process by which a liquid material is (usually poured into a mold which These mold processes include:

Pouring

An old geared ladle
An old geared ladle

In a foundry, molten metal is poured into molds. Molding is the process of Manufacturing by shaping pliable raw material using a rigid frame or model called a pattern. Pouring can be accomplished with gravity, or it may be assisted with a vacuum or pressurized gas. Many modern foundries use robots or automatic pouring machines for pouring molten metal. Traditionally, molds were poured by hand using ladles. In Foundry work a ladle is a container used to transport and pour out molten metals

Shakeout

The solidified metal component is then removed from its mold. Where the mold is sand based, this can be done by shaking or tumbling. This frees the cast component, which will still be attached to the metal runners and gates - which are the channels through which the molten metal travelled to reach the component itself.

Degating

Degating is the removal of the heads, runners, gates, and risers from the casting. Runners, gates, and risers may be removed using cutting torches, band saws or ceramic cutoff blades. Concerning a. " for the verdict on this matter --> Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding A band saw uses a blade consisting of a band of toothed metal and may be powered by wind water steam electrical motor or animal power For some metal types, and with some gating system designs, the sprue, runners and gates can be removed by breaking them away from the casting with a hammer or specially designed knockout machinery. Risers must usually be removed using a cutting method (see above) but some newer methods of riser removal use knockoff machinery with special designs incorporated into the riser neck geometry that allow the riser to break off at the right place.

The gating system required to produce castings in a mold yields leftover metal, including heads, risers and sprue, sometimes collectively called sprue, that can exceed 50% of the metal required to pour a full mold. Since this metal must be remelted as salvage, the yield of a particular gating configuration becomes an important economic consideration when designing various gating schemes, to minimize the cost of excess sprue, and thus melting costs.

Surface Cleaning

After Degating, sand or other molding media may adhere to the casting. To remove this the surface is cleaned using a blasting process. This means a granular media will be propelled against the surface of the casting to mechanically knock away the adhering sand. The media may be blown with compressed air, or may be hurled using a shot wheel. The media strikes the casting surface at high velocity to dislodge the molding media (for example, sand) from the casting surface. Numerous materials may be used as media, including steel, iron, other metal alloys, aluminum oxides, glass beads, walnut shells, baking powder or numerous other materials. The blasting media is selected to develop the color and reflectance of the cast surface. Terms used to describe this process include cleaning, blasting, shotblasting and sand blasting of castings.

Finishing

The final step in the process usually involves grinding, sanding, or machining the component in order to achieve the desired dimensional accuracies, physical shape and surface finish. Conventional Machining, one of the most important material removal methods is a collection of material-working processes in which power-driven Machine tools, such as lathes

Removing the remaining gate material, called a gate stub, is usually done using a grinder or sanding. Abrasive Paper is a form of Paper where an Abrasive material has been fixed to its surface These processes are used because their material removal rates are slow enough to control the amount of material. These steps are done prior to any final machining.

After grinding, any surfaces that requires tight dimensional control are machined. Many castings are machined in CNC milling centers. The abbreviation CNC stands for computer numerical control, and refers specifically to a computer "controller" that reads G-code A milling machine is a Machine tool used for the shaping of Metal and other Solid Materials. The reason for this is that these processes have better dimensional capability and repeatability than many casting processes. However, it is not uncommon today for many components to be used without machining.

A few foundries provide other services before shipping components to their customers. Painting components to prevent corrosion and improve visual appeal is common. Some foundries will assemble their castings into complete machines or sub-assemblies. Other foundries weld multiple castings or wrought metals together to form a finished product. Welding is a fabrication process that joins materials usually Metals or Thermoplastics by causing coalescence.

Advantages

The finished product of a foundry can be more geometrically complex than the product of a rolling, forging, or machining process like milling or turning. Rolling is a fabricating process in which the Metal, Plastic, Paper, Glass, etc Forging is the term for shaping metal by using localized compressive forces Conventional Machining, one of the most important material removal methods is a collection of material-working processes in which power-driven Machine tools, such as lathes The mechanical properties of castings are equal in every direction, which makes them more suitable for multi-directional loading conditions. A foundry is the original way to produce near net shape parts. Near net shape is an industrial production technique The name implies that the initial production of the item is very close to the final (net shape Castings frequently do not require or only require a little machining to create the finished part.

References

See also

External links

In the foundry processes coremaking can gain cut interior from parts or outdoor areas that cannot be obtained simply: presence of fins for example even counter-remains

Dictionary

foundry

-noun

  1. A facility that melts metals in special furnaces and pours the molten metal into molds to make products. Foundries are usually specified according to the type of metal dealt with, as iron foundry, brass foundry, etc.
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