Unit 11: Materials Science
LO3: Understand material processing techniques
Casting
Learner activity sheet
Activity 1
Casting is a common manufacturing process used to shape metals and other materials.
The image shows casting taking place, with molten metal being poured carefully into a mould.
There are many different types of casting method, each with its own particular characteristics and
application.
Explain the basic process for each of the following casting methods:
1.
Sand casting.
2.
Permanent mould casting.
3.
Investment casting.
4.
Die casting.
5.
Centrifugal casting.
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Activity 2
When molten metal is poured into a mould during casting, it will eventually cool and solidify. The
solidification process occurs in a particular order, creating differences in the grain structure in the metal.
Look at the diagram below which shows metal being poured into a mould. Labelled on the diagram are
four zones in which cooling takes place: chill zone, columnar zone, equiaxed zone and pipe.
1.
Explain the order in which solidification takes place.
2.
Explain how the structure of the metal (the grain structure) changes within each zone during
solidification.
3.
Explain the term “microsegregation” and what this means?
4.
What is the “pipe”?
5.
The photograph shows dendrites – what are dendrites and how do they form in the casting
process?
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