AWS Certified Welding Inspector — FundamentalsInspector Duties and ResponsibilitiesHard
A CWI is conducting a final visual inspection of a completed pressure vessel fabricated to ASME Boiler and Pressure Vessel Code, Section VIII. During the inspection, the CWI observes several areas where the weld reinforcement (crown) on a butt joint exceeds the maximum allowable height specified by the WPS and ASME Code. The WPS specifies a maximum weld reinforcement of 1/8 inch (3.2 mm) for plate thickness up to 1 inch (25 mm). The CWI measures a reinforcement of 3/16 inch (4.8 mm). What is the primary concern with excessive weld reinforcement?
- AIt creates stress risers at the toe of the weld, which can lead to fatigue cracking under cyclic loading.
- BIt indicates insufficient heat input during welding, leading to a weaker weld.
- CIt is purely an aesthetic issue and does not affect the mechanical integrity of the weld.
- DIt makes non-destructive testing (NDT) such as radiography more difficult to interpret accurately.
Show answer & explanationAnswer & explanation
Correct answer: A. It creates stress risers at the toe of the weld, which can lead to fatigue cracking under cyclic loading.
Excessive weld reinforcement creates an abrupt change in section thickness at the weld toe. This geometric discontinuity acts as a stress riser, concentrating stresses at that point, which can significantly reduce the fatigue life of the component, particularly in applications subjected to cyclic loading like pressure vessels.
Why the other options are wrong
- B. Excessive reinforcement typically indicates too much filler metal, not necessarily insufficient heat input.
- C. Excessive reinforcement is not purely aesthetic; it has significant mechanical implications.
- D. While it can complicate NDT, the primary structural concern is the stress concentration it creates.
Excessive Weld Reinforcement
Weld reinforcement (crown) that exceeds the maximum height specified by the WPS and applicable code. It creates stress concentrations at the weld toe, which can reduce fatigue life and impact the structural integrity of the weld.
- Geometric discontinuity at weld toe.
- Acts as a stress riser.
- Increases susceptibility to fatigue cracking.
Memory trick: Too high a crown, stress falls down hard.