A mechanic needs to loosen a severely rusted, seized steel nut from a steel bolt using an oxyacetylene torch. To successfully utilize the principles of thermal expansion to remove the fastener, arrange the following procedural steps and physical responses in their correct chronological sequence.
- 1Apply rapid, concentrated heat directly to the outer surface of the seized nut.
- 2The metal of the nut undergoes thermal expansion as its temperature rapidly rises, slightly increasing its internal diameter.
- 3Apply turning force to the nut with a wrench immediately, before significant heat can conduct into the inner bolt.
- 4The nut turns successfully because the temporary temperature difference has created physical clearance between the mated threads.
Cevap
The correct sequence is to first apply concentrated heat to the nut, which causes the nut to expand. Then, you must apply the wrench before the heat transfers to the bolt, allowing the nut to break free due to the temporary clearance.
For thermal expansion to loosen a seized assembly, the outer component (the nut) must be heated rapidly so it expands before the inner component (the bolt) has time to absorb the heat and expand as well. This creates a temporary difference in size that breaks the mechanical bind.
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Anahtar Kavram
Thermal Expansion in Mechanical Assemblies