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Explain how you will conduct the following tests to identify various metals: 3.1.1 Sound test 3.1.2 File test What is the purpose of the heat treatment of steel? What is the purpose of the case hardening of steel? Describe the tempering process of steel - NSC Mechanical Technology Automotive - Question 3 - 2020 - Paper 1
Question 3
Explain how you will conduct the following tests to identify various metals: 3.1.1 Sound test 3.1.2 File test What is the purpose of the heat treatment of steel? ... show full transcript
Worked Solution & Example Answer:Explain how you will conduct the following tests to identify various metals: 3.1.1 Sound test 3.1.2 File test What is the purpose of the heat treatment of steel? What is the purpose of the case hardening of steel? Describe the tempering process of steel - NSC Mechanical Technology Automotive - Question 3 - 2020 - Paper 1
Step 1
3.1.1 Sound test
Answer
To conduct the sound test, take a metal object and tap it with a hammer. Listen carefully to the sound produced; each metal has a distinct sound that can help in identification. Alternatively, drop the metal on a hard surface and identify the sound it makes. This sound will also provide cues about the metal's properties.
Step 2
3.1.2 File test
Answer
For the file test, use a metal file to scrape the surface of the metal. Pay close attention to the bite of the file into the metal. If the file bites easily into the metal, it indicates that the metal is softer. On the other hand, if the bite is minimal, the metal is likely to be harder.
Step 3
What is the purpose of the heat treatment of steel?
Answer
The purpose of heat treatment of steel is primarily to change its properties. This can include altering its hardness, strength, and ductility. Additionally, heat treatment can change the grain structure of steel, resulting in improved performance and longevity.
Step 4
Step 5
Describe the tempering process of steel.
Answer
The tempering process involves heating the steel to a specific temperature below its critical temperature. First, the steel is heated to a predetermined temperature to alter its properties. It is then soaked at that temperature for a certain period, allowing for uniform heat distribution. Finally, the steel is quenched in an appropriate medium, such as water, brine, or oil, to relieve internal stresses and enhance toughness.
Step 6
Name the THREE factors which need to be taken into consideration when heat treatment of steel is done.
Answer
- Heating temperature / Carbon content: The temperature at which steel is heated affects its properties significantly.
- Soaking time (Time period at temperature / Work piece size): The duration for which the steel is held at the heating temperature plays a critical role in ensuring even treatment.
- Cooling rate / Quenching rate: This factor is important for achieving the desired hardness and strength in the treated steel.