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ENGINEERING, PPT 2023 HSC 14 MC

A piece of 0.8% \(\ce{C}\) steel is heated to above its recrystallisation temperature and then normalised.

In what medium is this piece of steel cooled?

  1. Air
  2. Brine
  3. Sand
  4. Water
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\( A \)

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  • Normalising involves heating steel to an elevated temperature, followed by slow cooling to room temperature, which changes the microstructure of the steel, reducing its hardness and increasing its ductility.

\(\Rightarrow A \)

ENGINEERING, PPT 2016 HSC 26c

Structural steel `text{I}`-beams are used to make a crane were hot-rolled then normalised.

Explain why normalising was chosen as the heat treatment process. Support your answer with a labelled sketch of the resulting microstructure.   (4 marks)


 

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Advantages of normalising:

  • An increase in strength. Grain size strengthening is achieved due to the fine uniform grain structure produced by normalising.
  • When compared to other strengthening methods it is relatively economical.
  • Normalising relieves stress.
     

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Advantages of normalising:

  • An increase in strength. Grain size strengthening is achieved due to the fine uniform grain structure produced by normalising.
  • When compared to other strengthening methods it is relatively economical.
  • Normalising relieves stress.
     


♦ Mean mark 43%.

ENGINEERING, PPT 2019 HSC 24b

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

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

  1. 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%.

ENGINEERING, PPT 2021 HSC 25c

The pins in some truss joints are made from normalised mild steel.

How does the process of normalising affect the material properties of these pins?   (2 marks)

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  • Normalising involves heating mild steel to above red heat (austenitising) and cooling in still air to produce finer, equiaxed grains of pearlite and ferrite.
  • The finer grain structure results in a harder and stronger steel with optimal toughness and tensile strength.
Show Worked Solution
  • Normalising involves heating mild steel to above red heat (austenitising) and cooling in still air to produce finer, equiaxed grains of pearlite and ferrite.
  • The finer grain structure results in a harder and stronger steel with optimal toughness and tensile strength.

♦ Mean mark 50%.