1.1 The picture below shows a typical MIG welding machine - NSC Agricultural Technology - Question 4 - 2021 - Paper 1
Question 4
1.1 The picture below shows a typical MIG welding machine.
Identify A and B.
Name the TWO gases that are provided as a mixture in the cylinder at C.
What is the f... show full transcript
Worked Solution & Example Answer:1.1 The picture below shows a typical MIG welding machine - NSC Agricultural Technology - Question 4 - 2021 - Paper 1
Step 1
Identify A and B.
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Answer
A is the welding gun, which holds the wire and is used to create the weld. B is the crocodile clamp, also known as the earth clamp or earth connection, used to provide a ground for the welding circuit.
Step 2
Name the TWO gases that are provided as a mixture in the cylinder at C.
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The TWO gases typically provided in the cylinder at C are Argon and Carbon Dioxide (CO₂), or Helium.
Step 3
What is the function of the heat that is produced by the electric arc?
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Answer
The heat produced by the electric arc melts the metal to form a weld joint. This melting is critical as it allows the base metals to fuse together.
Step 4
What is the purpose of the gas shielding the weld bead?
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The purpose of the gas shielding is to protect the molten weld from atmospheric contamination, which could lead to defects in the weld, such as porosity.
Step 5
Name TWO non-ferrous metals that can be successfully welded with this machine.
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Answer
Two non-ferrous metals that can be successfully welded with a MIG welding machine include Aluminum and Titanium.
Step 6
Describe the function of a push-pull torch as found on an MIG welding machine.
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The push-pull torch is designed for aluminum welding. It features a pair of rollers that push the wire forward while pulling it back, ensuring that the wire is fed smoothly into the weld joint.
Step 7
What precautionary measures could be taken to overcome the problem of dripping metal when welding in the vertical up welding position?
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To prevent dripping metal while welding in the vertical up position, the following measures can be taken:
Use a special electrode designed for vertical welding.
Ensure the tip of the electrode is pointed upwards at an angle of about 30 degrees from the horizontal.
Maintain adequate arc control.
Ensure the welding speed is appropriate for the thickness of the metal.
Limit the movements of the electrode to reduce excess heat buildup.
