In order to increase the local cooling speed of the casting, the metal block placed in the cavity and the working surface is called chill.
Chill action:
(1) Prevent shrinkage cavity and porosity at the position where riser is difficult to be fed.
(2) Divide the feeding area of the riser, control and expand the feeding distance of the riser, and improve the feeding efficiency of the riser.
(3) Accelerate the solidification of the cross part and the sharp change part of the wall thickness to avoid hot cracks.
(4) Improve the local microstructure and mechanical properties of castings. For example, refine the matrix structure and improve the mechanical properties of castings
There are many materials that can be used to make cold iron. All metal and non-metal materials with higher thermal conductivity and heat storage coefficient than the casting materials can be selected. The commonly used cold iron materials in production are steel, cast iron, copper alloy, aluminum alloy and graphite, magnesia, carbon sand, chrome magnesia, etc.
F cast iron and steel chill are widely used, with large heat storage capacity, can absorb more heat, strong chilling capacity, convenient manufacture and low cost. It is widely used in the production of various alloy castings. This design selects the cast iron external cold iron.