QUESTION 4: MATERIALS
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
QUESTION 4: MATERIALS
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 Pear... show full transcript
Worked Solution & Example Answer:QUESTION 4: MATERIALS
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
4.1.1 Pearlite
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Pearlite is characterized by good ductility and being hard. It is known for its strong and tough nature, alongside its resistance to deformation.
Step 2
4.1.2 Cementite
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Cementite is defined as being intensely hard and brittle. These properties significantly influence its application in steel structures.
Step 3
4.2.1 Lower critical point (AC1)
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The lower critical point (AC1) is the lowest temperature to which steel must be heated to achieve hardening. It marks the temperature at which the microstructure of steel begins to change.
Step 4
4.2.2 Higher critical point (AC3)
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The higher critical point (AC3) marks the highest temperature at which steel can be heated to obtain maximum hardness. It is also the temperature at which the steel loses its magnetic properties and reaches its finest structure.
Step 5
4.3 Which ELEMENT determines the hardness of steel with reference to the iron-carbon equilibrium diagram?
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The carbon content in steel determines its hardness, as higher carbon levels lead to increased hardness.
Step 6
4.4 Which STRUCTURE in steel determines the hardness?
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The structure of cementite in steel is responsible for determining hardness, as it contributes to the overall strength and resistance to deformation.
Step 7
4.5 Which STRUCTURE in steel determines the ductility?
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The ferrite structure in steel is what determines ductility, allowing the material to deform without breaking.
Step 8
4.6 Describe the austenite structure.
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Austenite is a solid solution of iron and carbon, recognized as a crucial phase in steel metallurgy. Its structure is face-centered cubic (FCC), which provides greater ductility and toughness compared to other phases.
