Fig. 1 shows a welded joint that failed in service. Which labelled feature indicates that the weld did not fuse to the root of the joint? [1]

Assessment: Design & Technology: Product Design 9252 | Paper 1 Mock 01 | Technical, designing and making principles Subject: Design & Technology: Product Design - 9252

Question 1 Report

9252-p1-techniques-weld-root-defect-1

Fig. 1 shows a welded joint that failed in service. Which labelled feature indicates that the weld did not fuse to the root of the joint? [1]

Answer Details

Feature B indicates lack of root fusion. The root is the deepest part of a welded joint, where the two pieces should be joined completely. A visible unjoined gap or boundary at this point shows that molten weld metal did not fuse through to the root. This creates a weak plane in the joint, so it can fail when loaded. [1]

Examination reminder: distinguish a surface defect from a root defect: lack of root fusion is found at the base of the weld joint.

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