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4.1 MIG welding is easy because it requires less skill than conventional arc welding - NSC Agricultural Technology - Question 4 - 2017 - Paper 1
Question 4
4.1 MIG welding is easy because it requires less skill than conventional arc welding. 4.1.1 Name THREE settings on the MIG welding machine that should be adjusted b... show full transcript
Worked Solution & Example Answer:4.1 MIG welding is easy because it requires less skill than conventional arc welding - NSC Agricultural Technology - Question 4 - 2017 - Paper 1
Step 1
Name THREE settings on the MIG welding machine that should be adjusted before starting a welding project.
Answer
- Welding Current/Arc Strength: Adjusting the welding current is crucial as it affects the heat and penetration of the weld.
- Gas Supply Pressure: The gas pressure should be set between 15 and 25 PSI to ensure a smooth shielding gas flow.
- Speed of Wire Feed: The speed at which the wire is fed into the weld pool must be calibrated for optimal performance.
Step 2
Step 3
What is wrong with the setting of the MIG welding machine if the welding operator burns holes into the work piece?
Answer
If the operator burns holes into the work piece, it usually indicates that the power of the welding machine is too high. This excessive power can lead to over-penetration and burn-through.
Step 4
Explain the procedure to extinguish an oxyacetylene flame when a welding job has been completed.
Answer
- Turn off the Acetylene Valve: Start by shutting off the acetylene valve on the torch handle, which stops the gas flow.
- Extinguish the Flame: This should extinguish the open flame.
- Turn off the Oxygen Valve: Next, turn off the oxygen valve on the torch handle to prevent any further supply.
- Check Safety Equipment: Always ensure that safety goggles are worn and verify that you are wearing appropriate gloves during this process.
- Store Equipment Properly: Close the valves on the gas cylinders and return them to their proper storage area.
Step 5
Describe the symptoms experienced when inhaling welding vapours from galvanized steel. State the name of this kind of poisoning.
Answer
When inhaling welding vapours from galvanized steel, symptoms may include:
- Flu-like symptoms such as headaches, fever, and sinus irritation.
- Severe respiratory distress potentially leading to pneumonia, referred to as 'metal fume fever.' This condition is associated with the inhalation of zinc oxide fumes released during welding on galvanized materials.