Processes for Casting of Metals Dec07

Processes for Casting of Metals...

Processes for Casting of Metals Casting of metals is a process of manufacturing materials made of metals. It is a forming process for the forming of hot liquid metals. It is the simplest, most direct route to a near net shape product, and often the least expensive.  It is a process, in which liquid metal is poured into a mould, which contains a hollow cavity of the desired shape, and then allowed to cool and solidify. The solidified part is also known as a casting, which is ejected or removed out of the mould to complete the process. Casting is very often used for making complex shapes which are difficult or uneconomical to make by other methods. The processes for the casting of metals (Fig 1) have two distinct subdivisions namely (i) non-expendable mould casting, and (ii) expendable mould casting. It is further broken down by the mould material, such as sand or metal, and pouring method, such as gravity, vacuum, or low pressure. Fig 1 Processes for the casting of metals Non-expendable mould casting processes Non-expendable mould casting is a casting process in which the mould need not be reformed after each production cycle. Non-expendable mould casting is a casting technique which has at least 4 distinct casting processes. These are (i) continuous casting, (ii) centrifugal casting, (iii) die casting, and (iv) permanent mould casting. This form of casting also results in improved repeatability in parts produced and delivers near net shape casting. Continuous casting process Continuous casting of metals can be defined as a refined process of casting for continuous production in high volume of metal shapes with constant cross-section. During the process, the pouring of liquid metal takes place into a water-cooled, open-ended copper mould. This allows a skin of solid metal being formed...