4.1 Temperature affects the structure of steel with regard to iron and carbon - NSC Mechanical Technology Automotive - Question 4 - 2016 - Paper 1
Question 4
4.1 Temperature affects the structure of steel with regard to iron and carbon. State TWO characteristics of each of the following:
4.1.1 Pearlite
4.1.2 Cementite
4... show full transcript
Worked Solution & Example Answer:4.1 Temperature affects the structure of steel with regard to iron and carbon - NSC Mechanical Technology Automotive - Question 4 - 2016 - Paper 1
Step 1
State TWO characteristics of each of the following: Pearlite
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Answer
Pearlite exhibits good ductility, allowing it to deform without breaking.
It is also hard, providing resistance to wear and indentation.
Step 2
State TWO characteristics of each of the following: Cementite
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Answer
Cementite is intensely hard, giving it high wear resistance.
It is brittle, which makes it susceptible to fracture under stress.
Step 3
Explain the following terms used in the iron-carbon equilibrium diagram: Lower critical point (A_C1)
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Answer
The lower critical point (A_C1) is defined as the lowest temperature to which steel must be heated to facilitate hardening.
It is also identified as the temperature at which the structure begins to change.
Step 4
Explain the following terms used in the iron-carbon equilibrium diagram: Higher critical point (A_C3)
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Answer
The higher critical point (A_C3) represents the highest temperature to which steel can be heated to achieve maximum hardness.
At this point, the steel's structure is at its finest, and it loses its magnetic properties.
Step 5
Which ELEMENT determines the hardness of steel with reference to the iron-carbon equilibrium diagram?
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Answer
Carbon content is the key element that determines the hardness of steel.
Step 6
Which STRUCTURE in steel determines the hardness?
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Answer
The cementite structure in steel is responsible for determining its hardness.
Step 7
Which STRUCTURE in steel determines the ductility?
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The ferrite structure in steel is what governs its ductility.
Step 8
Describe the austenite structure.
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Austenite is a solid solution of iron and carbon, also referred to as iron carbide.
This structure is essential for its ductility and strength.
