Identify two important advantages of casting processes.
Large and mass produced
1 of 15
Identify two limitations or disadvantages of casting.
Environmental problems and safety hazards due to handling of hot metals
2 of 15
Name the two basic mold types that distinguish casting processes.
Expendable and permanent
3 of 15
Which casting process is the most important commercially?
Sand casting
4 of 15
What is the difference between a pattern and a mold?
The pattern is the final shape used to create the mold, the mold is a hollow cavity where molten metal is poured.
5 of 15
Draw a labelled diagram of a typical closed sand mold with a core.
Downsprue, runner, flask, mould, pouring cup, riser, cast metal in cavity, core, cope, parting line, drag.
6 of 15
What is the most commonly cast metal in sand casting?
Cast iron
7 of 15
What are the most common metals used in die casting?
zinc, tin, lead, aluminum, brass, and magnesium.
8 of 15
What material could the dies be made from in die casting?
At low melting points, typically the dies are made from steel. However, if cast iron is the molten metal then the die used must have a higher melting point
9 of 15
Which die-casting machines usually have a higher production rate, cold-chamber or hot-chamber, and why?
Hot chambers, because they have a higher production rate as they inject the molten metal into the cast rather than ladling it which takes less time
10 of 15
What is flash in die casting?
Flash is a thin piece of metal as a result of the molten metal being squeezed at the parting line
11 of 15
How does solidification of alloys differ from solidification of pure metals? Include a basic, labelled cooling curve for each in your answer.
Metals cool at at a single temperature equal to their melting point, alloys start to solidify at the liquids line and completely solidify at the solidus line
12 of 15
Describe the reasons for the flat thermal arrest region in the cooling of a pure metal
The change from liquid to soild releases latent heat. Local solidification releases this energy as heat to the surrounding material which remains at the freezing temperature until no more latent heat can be extracted
13 of 15
What are some of the operations required in sand casting after the casting is removed from the mold?
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