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Answer any three of the following: (i) Describe three hazards associated with the use of manual metal arc welding in a school engineering room - Leaving Cert Engineering - Question a - 2013
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Answer any three of the following: (i) Describe three hazards associated with the use of manual metal arc welding in a school engineering room. (ii) Outline the func... show full transcript
Worked Solution & Example Answer:Answer any three of the following: (i) Describe three hazards associated with the use of manual metal arc welding in a school engineering room - Leaving Cert Engineering - Question a - 2013
Step 1
Describe three hazards associated with the use of manual metal arc welding in a school engineering room.
Answer
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Electric Shock: Manual metal arc welding involves high voltages that can pose a risk of electric shock. It is essential that welding equipment is well maintained and that proper grounding techniques are followed.
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Fumes: Welding generates fumes that can be harmful if inhaled. Adequate ventilation systems should be in place to reduce exposure.
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Hot Metals: The heat produced during welding can cause burns. Protective gear such as gloves and aprons must be worn to shield against these hazards.
Step 2
Outline the functions of the transformer, capacitor and rectifier in manual metal arc welding.
Answer
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Transformer: The transformer reduces the incoming voltage (220V) to a suitable level (usually 100V or lower) for welding. It provides the current needed for welding by converting high voltage into a manageable form.
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Capacitor: The capacitor smooths out the voltage supply, ensuring a steady current for the welding process. This helps to maintain an arc stability.
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Rectifier: The rectifier changes alternating current (AC) into direct current (DC), allowing for better control over the welding process through a consistent output that promotes quality welds.
Step 3
State two functions of the electrode coating in manual metal arc welding.
Answer
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Protection: The coating helps to shield the welded joint from contamination by atmospheric gases such as oxygen and nitrogen.
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Slag Formation: It assists in forming a slag which protects the weld from oxidation and ensures a more stable cooling rate, preventing defects in the weld.
Step 4
State specific uses for each of the following welding processes:
Answer
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Tungsten Inert Gas (TIG) Welding: Commonly used for welding aluminum and stainless steel materials, TIG provides high-quality, precise welds.
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Submerged Arc Welding (SAW): Frequently utilized in applications requiring large, deep welds, such as in shipbuilding and bridge construction.
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Oxy-Acetylene Welding: Primarily used for fabricating and repairing automotive bodies and in some cases, for joining different kinds of metal.