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Explain any two of the following processes: (i) Quenching (ii) Case hardening (iii) Annealing (iv) Work hardening - Leaving Cert Engineering - Question 3 - 2021
Question 3
Explain any two of the following processes: (i) Quenching (ii) Case hardening (iii) Annealing (iv) Work hardening. (b) Describe how to carry out each of the fol... show full transcript
Worked Solution & Example Answer:Explain any two of the following processes: (i) Quenching (ii) Case hardening (iii) Annealing (iv) Work hardening - Leaving Cert Engineering - Question 3 - 2021
Step 1
To harden the point of a centre punch:
Answer
To harden the point of a centre punch, first heat the point to approximately 800°C until it reaches a cherry red color. It is crucial to maintain this temperature to ensure effective hardening. Once the desired temperature is achieved, immediately immerse the punch in water or oil. This rapid cooling process hardens the metal, creating a hard, durable point suitable for making impressions.
Step 2
To temper the cutting edge of a cold chisel:
Answer
To temper the cutting edge of a cold chisel, first, the chisel is reheated to a suitable temperature. This usually means heating it just below the red color, ensuring the metal doesn't reach a point where it becomes too soft. The cutting edge should be cooled slowly in still air or submerged in oil. The tempering process is indicated by a change in color that ranges from straw to blue, which reflects the hardness characteristics of the chisel's cutting edge.
Step 3
State two safety precautions to be observed during the heat treatment of metals:
Answer
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Wear heat-resistant gloves when performing heat treatment of metals to protect your hands from burns.
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Do not leave hot metals lying around in case someone accidentally picks up the piece, as this can lead to serious injuries.