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8.1 State THREE measures to prevent incomplete penetration during the arc-welding process - NSC Mechanical Technology Welding and Metalwork - Question 8 - 2024 - Paper 1
Question 8
8.1 State THREE measures to prevent incomplete penetration during the arc-welding process. 8.2 State TWO common weld defects that can be identified by visual inspec... show full transcript
Worked Solution & Example Answer:8.1 State THREE measures to prevent incomplete penetration during the arc-welding process - NSC Mechanical Technology Welding and Metalwork - Question 8 - 2024 - Paper 1
Step 1
State THREE measures to prevent incomplete penetration during the arc-welding process.
Answer
To prevent incomplete penetration during the arc-welding process, the following measures can be taken:
- Use correct travel speed: Ensure that the welding machine departs from the joint at the correct speed to allow adequate penetration.
- Use narrow/correct joint: Opt for a joint design that allows for better penetration and reinforcing of the weld.
- Use correct welding current: Adjust the welding current to match the material and thickness being welded, ensuring proper fusion.
Step 2
State TWO common weld defects that can be identified by visual inspection.
Answer
Two common weld defects identifiable by visual inspection include:
- Cracks: Visible fissures on the weld surface that can weaken the joint.
- Undercutting: A groove or void along the edge of the weld that can reduce strength.
Step 3
Explain the term fusion in arc welding.
Answer
Fusion in arc welding refers to the proper bonding of the weld metal with the base metal. This occurs when the heat from the welding arc sufficiently melts both the filler material and the edges of the base metals, allowing them to join together as they cool.
Step 4
What can be done to address undercutting in a welded joint?
Answer
To address undercutting in a welded joint, the following actions can be taken:
- Adjust the welding parameters: Ensure the voltage and current settings are optimal.
- Control heat input: Modify travel speed or electrode angle to prevent excessive melting of the base metal.
- Ensure proper electrode angle: Maintain the correct angle to prevent excessive undercutting.
Step 5
Step 6
Explain the significance of consistent width and height of a weld bead in ensuring weld quality.
Answer
The consistent width and height of a weld bead are significant because they provide the necessary structural integrity and proper strength distribution along the joint. A uniform bead ensures that the load is evenly distributed, which improves the overall performance and durability of the weld.
Step 7
Describe THREE factors that should be considered during weld inspection.
Answer
Three factors that should be considered during weld inspection include:
- Clean bead surface: Ensure the bead is free from any contaminants.
- Constant width and height: Verify that the weld maintains consistent measurements throughout its length.
- Absence of cracks: Check for visible cracks indicating potential failure points in the weld.
Step 8
Explain how to conduct the liquid dye penetration test on a welded joint.
Answer
To conduct the liquid dye penetration test on a welded joint, follow these steps:
- Clean the surface: Ensure the area to be tested is free from contaminants.
- Apply the dye: Spray or apply the liquid dye penetrant to the surface and allow it to seep into any defects.
- Remove excess dye: After allowing it to sit, use a cleaner to remove the excess dye from the surface.
- Develop the results: Use a developer that reacts with the dye to highlight surface defects.
- Inspect for defects: Examine the surface for any indications of defects, which will appear as colored spots.