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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
4.1.1 Name THREE settings on the MIG welding machine that should be adjusted before starting a welding project.
Answer
Before starting a MIG welding project, the following three settings should be adjusted:
- Welding Current/Arc Strength: This determines the heat level used in the welding process and is critical for achieving a proper weld.
- Gas Supply Pressure: The gas pressure should be set within a range of 15 to 25 PSI to ensure a proper shield for the weld area.
- Wire Feed Speed: This controls how quickly the welding wire is fed into the weld pool, affecting the quality and speed of the welding process.
Step 2
4.1.2 You can tell a fair amount about the quality of a MIG welding process by the way it sounds. Describe the correct sound that the MIG welding process should make.
Answer
The MIG welding process should make a continuous sparking sound, often likened to an egg frying on a hot skillet. This consistent sound indicates a stable arc and good penetration into the base material.
Step 3
4.1.3 What is wrong with the setting of the MIG welding machine if the welding operator burns holes into the work piece?
Answer
If the welding operator is burning holes into the work piece, it indicates that the power of the welding machine is set too high. Reducing the power setting will help to achieve a more controlled weld and prevent excessive penetration.
Step 4
4.2.1 Explain the procedure to extinguish an oxyacetylene flame when a welding job has been completed.
Answer
To safely extinguish an oxy-acetylene flame after completing a welding job, follow this procedure:
- Turn off the acetylene valve on the torch handle to extinguish the flame.
- Turn off the oxygen valve on the torch handle to close off the gas supply completely.
- Next, ensure your safety goggles or mask are properly removed and put on your welding gloves if they were taken off.
- Turn the main cylinder valve clockwise on top of both gas cylinders to close them.
- Finally, place the torch on a stable surface and disconnect the hoses.
Step 5
4.2.2 Describe the symptoms experienced when inhaling welding vapours from galvanised steel. Identify and give the name of this kind of poisoning.
Answer
When inhaling welding vapours from galvanised steel, symptoms include:
- Flu-like symptoms such as headaches, nausea, and sinus issues.
- Severe cases may cause mild respiratory distress, sometimes referred to as metal fume fever. This condition arises due to the zinc coating vaporizing during the welding process, leading to toxic exposure.