3.1 Define tempering of steel - NSC Mechanical Technology Welding and Metalwork - Question 3 - 2022 - Paper 1
Question 3
3.1 Define tempering of steel.
3.2 Give THREE reasons why the annealing process is conducted on steel?
3.3 At what approximate temperature is steel heated during t... show full transcript
Worked Solution & Example Answer:3.1 Define tempering of steel - NSC Mechanical Technology Welding and Metalwork - Question 3 - 2022 - Paper 1
Step 1
Define tempering of steel.
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Answer
Tempering is a process generally applied to steel to relieve the strains, brittleness, and improve ductility induced during the hardening process. It aims to enhance the overall mechanical properties of the steel.
Step 2
Give THREE reasons why the annealing process is conducted on steel?
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Answer
To relieve internal stresses that may have been set up during working of metal.
To soften steel in order to facilitate the machining process.
To refine their grain structure and reduce brittleness.
Step 3
At what approximate temperature is steel heated during the normalising process?
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Answer
Steel is typically heated to a temperature above the upper critical temperature, usually above 800°C.
Step 4
Identify the type of steel/iron from the spark patterns shown in FIGURES 3.4.1–3.4.3 below.
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Answer
A. Tempering range / °C
B. AC₃ line / Higher/upper critical temperature line
C. AC₁ line / Lower critical temperature line
D. Carbon content / % carbon
