Leaving Cert Engineering Heat Treatment: a) (i) Explain two heat treatme

a) (i) Explain two heat treatment processes carried out at cutting edge A during the manufacture of the cold chisel shown - Leaving Cert Engineering - Question a - 2019

Question a

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a) (i) Explain two heat treatment processes carried out at cutting edge A during the manufacture of the cold chisel shown. (ii) State the mechanical property most ... show full transcript

Worked Solution & Example Answer:a) (i) Explain two heat treatment processes carried out at cutting edge A during the manufacture of the cold chisel shown - Leaving Cert Engineering - Question a - 2019

Step 1

Explain two heat treatment processes carried out at cutting edge A during the manufacture of the cold chisel shown.

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Answer

Hardening: This process involves heating the cold chisel's cutting edge to a temperature where it becomes cherry red (around 900°C) and then rapidly cooling it by quenching in water. This treatment increases the hardness of the material, making it suitable for cutting operations.
Tempering: After hardening, tempering is performed to reduce brittleness. The tip A is heated to about 200°C to 300°C, allowing some relaxation of the internal stresses while maintaining hardness.

Step 2

State the mechanical property most associated with the cutting edge at A.

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The mechanical property most associated with the cutting edge at A is hardness, as hardening processes enhance the material's ability to resist deformation and wear during cutting.

Step 3

State the mechanical property most associated with the head of the cold chisel shown at B.

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Answer

The mechanical property most associated with the head B is toughness. This property allows the material to absorb energy and withstand impacts without fracturing.

Step 4

Describe each of the following with regard to heat treatment: Quenching.

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Answer

Quenching is a rapid cooling process employed after heating. When a cherry red metal is immersed in cold water, it cools quickly, increasing its hardness. However, this can also induce brittleness, which may necessitate further treatments like tempering.

Step 5

Describe each of the following with regard to heat treatment: Work hardening.

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Answer

Work hardening occurs when a metal is mechanically deformed, such as by hammering or shaping. This process increases the material's strength and hardness due to dislocation movements within the metal's crystal structure.

Step 6

State two safety precautions to be observed when cooling hot metals.

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Answer

Wear protective clothing to guard against hot water splashes or rising steam.
Be cautious of flames when cooling hot metals in oils, to prevent fire hazards.

a) (i) Explain two heat treatment processes carried out at cutting edge A during the manufacture of the cold chisel shown - Leaving Cert Engineering - Question a - 2019

Worked Solution & Example Answer:a) (i) Explain two heat treatment processes carried out at cutting edge A during the manufacture of the cold chisel shown - Leaving Cert Engineering - Question a - 2019

Explain two heat treatment processes carried out at cutting edge A during the manufacture of the cold chisel shown.

State the mechanical property most associated with the cutting edge at A.

State the mechanical property most associated with the head of the cold chisel shown at B.

Describe each of the following with regard to heat treatment: Quenching.

Describe each of the following with regard to heat treatment: Work hardening.

State two safety precautions to be observed when cooling hot metals.

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