The technology of melting metals and alloys and the shape and condition of them is called Foundry.
Foundry has advantages and disadvantages, including the advantages of producing components with complex geometric shapes that cannot be produced in other ways, and are also suitable for the production of very large pieces and are also suitable for polymers and ceramics.
One of the disadvantages is the danger to the worker of molten material, also limitations in mechanical properties.
In foundry, the method is to first melt the metals and throw in pre-designed molds and then cool down the metal. This method of foundry is the oldest process in the industry.
In ancient times, foundry furnaces were made of clay and sheets of copper and wood were placed there
Types of foundry methods:
Casting is usually done in a Foundry (Foundry Workshop).
The mold contains a compartment that forms the shape of a piece. Because of metal contraction after freezing, the dimensions of the compartment should be slightly larger than the actual size of the piece. The mold is made of various shapes such as sand, plaster, plastics, wood, metal and ceramics.
We have several casting molds including:
Foundry molds are either temporary or permanent, in the temporary format after freezing of the mold, it is possible to produce more complex shapes in these molds.
In the permanent molds, after freezing, the mold will be removed without destroying it, and more can be produced with these molds.
The amount of melting in the mold should not be too much and not too slow.
If poured slowly, there is a possibility of freezing
This sand is of a special type and mainly silica sand, which is obtained in limited areas in Iran and is used depending on the type and appearance of sand grains in the casting of small and large steel parts. Of course, there are other uses of this sand, especially in the treatment of drinking water and … But more than 80% of the mining of this mineral sand is used in the casting industry.
Clay with water is used as a sandblast. General composition: 90% sand, 7% clay and 3% water.
Other adhesives that are used include:
Sand adds to it.
Adding Gilsonite to sand foundry will make adhesion between sand and other materials.
This adhesion after filling the mold causes the gassing out of the Gilsonite sublimation to squeeze the material so that it is easier to separate the mold from the casting material. Meanwhile, the mold surfaces remain highly polished.
Foundry inside the sandy molds
Sand foundry is the oldest and most commonly used method for the foundry of aluminum, steel and other metals and has a low investment advantage with flexible casting design, a wide selection of alloys and easy design change.
In this method of foundry, a piece in Sand foundry mold is formed.
The melt is poured into the mold and formed after freezing. Almost all metals are cast in this way.
The mold cavity is formed by squeezing the sand around the model and then removing the mold into two halves and forming the mold from inside the mold.
A good sandy mold should have high strength, permeability (for air and gases release), high thermal stability, and recovery capability (sand for the production of other components).