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8.1 Identify the weld defects in FIGURES 8.1.1 and 8.1.2 below - NSC Mechanical Technology Welding and Metalwork - Question 8 - 2023 - Paper 1
Question 8
8.1 Identify the weld defects in FIGURES 8.1.1 and 8.1.2 below. 8.1.1 8.1.2 8.2 What are the main reasons for inspecting welds? 8.3 State TWO weld defects that c... show full transcript
Worked Solution & Example Answer:8.1 Identify the weld defects in FIGURES 8.1.1 and 8.1.2 below - NSC Mechanical Technology Welding and Metalwork - Question 8 - 2023 - Paper 1
Step 1
Identify the weld defects in FIGURES 8.1.1 and 8.1.2 below.
Answer
8.1.1: The defect in this figure is slag inclusion which occurs when slag is trapped in the weld bead.
8.1.2: The defect in this figure is incomplete penetration, indicating that the weld did not completely fuse with the base material.
Step 2
What are the main reasons for inspecting welds?
Answer
The main reasons for inspecting welds are:
- To check for weld quality: This ensures the weld strength and integrity meet required standards.
- To check for specification: It ensures that the weld conforms to the design and regulatory requirements.
Step 3
State TWO weld defects that can be revealed when conducting the following tests:
Answer
8.3.1 Nick-break test:
- Lack of fusion: where the weld does not properly fuse with the base metal.
- Internal quality: issues within the weld that are not visible externally.
8.3.2 Guided bend test:
- Quality of face of the weld joint: evaluating surface-related issues.
- Degree of penetration: confirming the weld penetrates adequately into the base material.
Step 4
Step 5
State THREE methods used to reduce transverse cracks.
Answer
- Preheat the base metal: Reducing the rate of cooling to help minimize stress.
- Using lower strength consumables: Ensures that the welding materials are compatible with the base material.
- Slow cooling after weld completion: Reduces the risk of sudden temperature changes that can lead to cracking.
Step 6
Step 7
State THREE advantages of using a liquid dye penetration test on a welded joint.
Answer
- Low cost: Generally inexpensive compared to other testing methods.
- Easy to apply: The procedure is straightforward and can be conducted by various personnel.
- Easy to interpret: The results are typically clear, allowing for quick evaluations of weld integrity.
Step 8
Describe the procedure to follow when performing an ultrasonic test on a welded joint.
Answer
- Clean the area on the metal to be tested: Ensures accurate readings by removing contaminants.
- Calibrate the equipment before commencement of testing: Guarantees that the test is set correctly.
- Apply gel, oil or water to the area on the metal: Improves sound wave transmission.
- Move probe left-to-right along the area on the metal: This allows for comprehensive coverage of the weld area.
- Soundwaves is sent and received: Assess the integrity of the weld based on the return signal.
- Interpret the flaws detected on the oscilloscope: Analyze the results to identify any inconsistencies or defects.