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3.1 Explain how you will prevent damage to a file when conducting a filing test on a hard metal - NSC Mechanical Technology Automotive - Question 3 - 2019 - Paper 1
Question 3
3.1 Explain how you will prevent damage to a file when conducting a filing test on a hard metal. 3.2 What is the purpose of the heat treatment of steel? 3.3 Give T... show full transcript
Worked Solution & Example Answer:3.1 Explain how you will prevent damage to a file when conducting a filing test on a hard metal - NSC Mechanical Technology Automotive - Question 3 - 2019 - Paper 1
Step 1
Explain how you will prevent damage to a file when conducting a filing test on a hard metal.
Answer
To prevent damage to a file during a filing test on hard metal, consider the following techniques:
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Use Proper Filing Skills: Employ the right filing techniques by maintaining a consistent angle and applying pressure gradually. This minimizes wear on the file.
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File on the Tip or Edge: Focus on filing with the tip or edge of the file instead of the flat surface. This method reduces contact area, limiting damage.
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Apply Chalk to the File Surface: Regularly apply chalk to the file surface which helps to keep the file clean from metal shavings and provides a better grip.
Step 2
Step 3
Give TWO reasons for tempering hardened steel.
Answer
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To Reduce Brittleness: Tempering is essential to reduce the brittleness that arises from the hardening process, making the metal more workable.
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To Increase Toughness: The tempering process improves the toughness of the steel, helping it to withstand impact and stress without cracking.
Step 4
Describe how the following heat treatment processes are carried out on steel:
Answer
3.4.1 Annealing:
- The steel is heated to a prescribed temperature, appropriate for the type of steel being used.
- It is then soaked at this temperature for a specific duration to allow for uniform heating.
- Finally, the steel is cooled very slowly, often in a furnace, to achieve maximum softness and relieve internal stresses.
3.4.2 Hardening:
- The steel is initially heated slightly above the upper critical temperature (A3C).
- It is held at this temperature to allow for complete austenitization.
- Subsequently, the steel is rapidly cooled by quenching in a medium such as oil or water to lock in hardness.