The special feature of this kind of casting is much higher quality of the surface, but the production of chill-moulds is labour-consuming and it can be paid off only by the considerable volume of production of the same castings.
A chill-mould is a metal form which has a protective fire-resistant facing on the working surface. The filling of a chill-mould with liquid alloy and its hardening are carried out without any exposure on liquid metal, but only by gravity. Economic feasibility depends on the firmness of a chill-mould.
The advantages of chill-mould casting based on production experience.
- Relevant durability of the chill-mould and the accelerated cooling of the casting in it.
- Sharp reduction or practically complete elimination of consumption of forming materials
- Increase in labour productivity in the result of elimination of labour-consuming operations in producing the mixtures, forming, cleaning the castings of scorch.
- Reduction of roughness of a surface, increase in density of castings and their accuracy.
- Mechanisation and automation of the process of casting caused by the multiplicity of the use of chill-mould.
Main operations and processes:
- The cleaning of the chill-mould of the old facing
- The warming of the chill-mould up to 200-300°C
- The coating of the working surface with the new layer of facing
- The setting of cores, the closing of the parts of the chill-mould
- Cooling and removing of the received ready-made casting
Nowadays the chill-mould casting is one of the most used kinds of castings, especially when it is necessary to produce big patches of castings or at the beginning of mass production of a special parts.