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.

Version 1

Activity 2When 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?

Version 1

Molten Metal

Chill Zone

Pipe

Equiaxed Zone

Columnar Zone

Mold