On the surface, the process of casting may come off as a simple task. It is just about pouring the liquid metal into a mould and set it. But over the years, the casting process has evolved into various types and intricate processes.
The first process of casting dates back to the 4th century in China. Since then, it has rolled into many innovations and development. In India, casting foundries flourished, providing the best iron products for commercial use.
A casting foundry follows the casting’s essential processes and decides its type based on the requirement and the scale of production. And we will discuss all of it here.
The Iron Casting Process
The iron casting process is carried out in a factory called cast iron foundry. The casting process is carried out in the following steps-
In the cast iron foundry, the primary metal or iron, internal scrap, external scrap, and alloying metal are melted in a furnace. The primary metal or virgin material is the one that is used to form an alloy. The furnace is heated above the melting point of the primary metal.
If the hydrogen concentration is higher in the mixture, it can increase the final product’s porosity. Higher porosity degrades the value of the product. Reducing the amount of hydrogen is called Degassing.
Generally, this is done by passing argon or nitrogen over the melt.
Moulding is usually done with a single-piece pattern or split pattern. The molten metal is poured into the moulds to get the desired shape of the final product. The patterns in the mould are made of wood, plastic, metal, or wax.
The construction of moulds depends on the type of molten metal, type of foundry, the casting size, the required quality of the final product.
4. Pouring And Degating
The molten iron is carefully poured into the mould by automatic machines or giant ladles. Once the metal solidifies, the runners, gates, risers, and heads are removed from the mould using cutting torches, bandsaw, and ceramic cutoff blades. This process is called degating.
The blasting process removes the unwanted debris that is still attached to the solidified material. Usually, this involves propelling tiny grinding balls over the material’s surface to remove unwanted debris like sand.
The tiny grinding balls are made up of glass beads, walnut shells, iron, aluminium oxides, steel, baking powder, etc.
Finally, the material is formed into the perfect dimensions by sanding or machining to even the rough edges. The product is now ready after clearing all the processes in the cast iron foundry.
Casting isn’t just of one type. Other types include sand casting, die casting, low-pressure casting, gravity die casting, centrifugal casting, vacuum die casting, continual casting lost foam casting, etc.
The casting foundry employs the type of casting according to the requirement of the final product. The processing time also varies according to the type of casting used.
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