AWS Certified Welding Inspector — FundamentalsInspector Duties and ResponsibilitiesMedium
A CWI is performing an in-process inspection of a multi-pass groove weld. The WPS specifies an interpass temperature range of 300°F to 400°F (149°C to 204°C). After completing a pass, the CWI measures the temperature of the weldment at 450°F (232°C) before the next pass is initiated. What is the appropriate action for the CWI to take?
- AInstruct the welder to wait until the weldment cools to within the specified interpass temperature range.
- BAllow the next pass to begin, as the temperature difference is minor and will not significantly affect weld quality.
- CDocument the temperature and allow the next pass, noting it as a minor deviation for review.
- DRequest the welding engineer to approve a temporary WPS revision for the higher interpass temperature.
Show answer & explanationAnswer & explanation
Correct answer: A. Instruct the welder to wait until the weldment cools to within the specified interpass temperature range.
Interpass temperature control is critical for preventing defects such as cracking, especially in certain materials. Exceeding the maximum interpass temperature can lead to detrimental metallurgical changes. The CWI's responsibility is to enforce the WPS, so the welder must wait for the weldment to cool.
Why the other options are wrong
- B. Exceeding interpass temperature limits can have significant metallurgical consequences, leading to potential defects; it's not a minor difference.
- C. Documenting and allowing the non-conformance to continue is a failure of the CWI's duty to prevent defective work.
- D. Seeking a WPS revision is a lengthy process that cannot be done on the fly for an immediate non-conformance and does not address the current violation.
Interpass Temperature Control
Interpass temperature is the temperature of the weld area before the next welding pass is deposited. It is critical for controlling cooling rates, preventing cracking, and ensuring proper metallurgical properties.
- Must be within WPS-specified range.
- Too high can lead to grain growth or hot cracking.
- Too low can lead to hydrogen-induced cracking.
- Monitored during welding inspection.
Memory trick: Hot welds need to 'Cool It!' before the next pass, or quality will 'Fail It!'