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The head of a steel axe is annealed, normalised, and tempered during manufacture - Leaving Cert Engineering - Question 3 - 2022
Question 3
The head of a steel axe is annealed, normalised, and tempered during manufacture. Describe any two of the following processes: (i) Annealing; (ii) Normalising; (ii... show full transcript
Worked Solution & Example Answer:The head of a steel axe is annealed, normalised, and tempered during manufacture - Leaving Cert Engineering - Question 3 - 2022
Step 1
Describe any two of the following processes: (i) Annealing;
Answer
Annealing is a heat treatment process used to soften metals. In this process, the steel is heated to a red cherry color, approximately 900°C, and allowed to cool down as slowly as possible. This can be achieved by leaving the metal in a furnace while the furnace is cooling down. The main purpose of annealing is to relieve internal stresses, enhance ductility, and improve the malleability of the metal.
Step 2
Describe any two of the following processes: (ii) Normalising;
Answer
Normalising is a heat treatment process used to make a metal more ductile and tough after processes such as thermal or mechanical hardening. The metal is heated to a temperature typically in the range of 830°C - 950°C and then cooled in air. This heating and slow cooling changes the microstructure of the steel, altering its mechanical properties.
Step 3
In relation to the heat treatment of steel, explain any two of the following: (i) Quenching;
Answer
Quenching is when a hot metal is cooled very quickly, for instance, when a cherry red metal is immersed in cold water. This rapid cooling process helps to harden the steel, making it more resilient.
Step 4
In relation to the heat treatment of steel, explain any two of the following: (ii) Carbon content;
Answer
The carbon content in steel significantly affects its properties. When iron is mixed with carbon, steel is produced. The amount of carbon (carbon content) mixed with iron determines the type of steel produced:
- Low carbon steel contains less than 0.03% of carbon.
- Medium carbon steel contains between 0.03% and 0.06% of carbon.
- High carbon steel contains more than 0.06% of carbon.