Chill is the chilled material placed inside the cavity, the surface of the cavity and the inside of the mold in order to speed up the local cooling rate of the casting. The chills are used in conjunction with the gating system and the riser system to control the solidification sequence of the castings to obtain qualified castings.
Chilled is divided into inner chill and outer chill. The metal chill block that is placed in the cavity and can be melted into the casting is called internal chills; while the metal chill block placed on the surface of the pattern (or core box) is called external chills. The internal chills will eventually become a part of the castings, so it should be made of the same material as the casting. The external chills can be recycled and reused.
Materials of the Chills:
Metallic Materials: high carbon steel, medium carbon steel, cast iron, cast copper, cast aluminium or the same materials as the desired castings.
Non-Metallic Materials: zircon sand, graphite, carbon sand, chrome magnesia, chrome sand, magnesia.
Functions of the Chills:
1) Reduce the size of the riser and increase the qualified rate. Practice has shown that through the reasonable use of chills and thermal insulation riser technology, the qualified rate of final metal castings could be much higher.
2) Placing chills in the appropriate part of the casting can improve the feeding channel. It can improve the internal quality level of castings and provide high-quality castings.
3) The use of chills in conjunction with the riser system can increase the feeding distance of the riser.
4) Eliminate local thermal stress and prevent cracks. For large steel castings, chromate sand or zircon sand with good chilling effect should be used.
5) Placing chills can accelerate the solidification rate of the casting, refine the grain structure, and improve the mechanical properties of the casting.
Post time: Mar-26-2022