smc-3719-20-Annealing

ENGINEERING, PPT 2017 HSC 5 MC

The image shows the microstructure of brass.

What type of grain structure does this image represent?

Deformed
Dendritic
Equiaxed
Stressed

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`C`

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→ All grains are relatively equiaxed, without any major deformities or stresses.

`=>C`

♦♦♦ Mean mark 23%.

ENGINEERING, PPT 2017 HSC 8 MC

Which row of the table correctly identifies how the properties of a cold worked metal are changed after annealing?

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`B`

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→ Generally, annealing is the heat treating of a metal to produce a soft (decrease in hardness), stress reduced (decrease in internal residual stress) state.

→ By decreasing the hardness and internal stress, the ductility will increase as well.

`=>B`

♦ Mean mark 49%.

ENGINEERING, PPT 2019 HSC 24b

Normalised high-tensile steel has been chosen for the manufacture of a wing support beam.

Draw and label the microstructures of a normalised high-tensile steel and an annealed high-tensile steel. (2 marks)

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Explain how the microstructure produced by normalising high-tensile steel improves the steel's suitability for this application. (2 marks)

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i. Microstructures

ii. → The strength of the steel is markedly increased.

→ Normalising produces finer and more uniform grains.

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i. Microstructures

♦♦♦ Mean mark (i) 26%.

ii. → The strength of the steel is markedly increased.

→ Normalising produces finer and more uniform grains.

♦ Mean mark (ii) 41%.