Structural Steel Welding Inspection
This domain tests how an inspector verifies that structural steel welding complies with the contract documents, project specification, governing welding code such as AWS D1.1, and the approved WPS. The inspector confirms hold points, records evidence, and stops nonconforming work before it is covered.
Inspection sequence
- Before welding: confirm the approved WPS, qualified welders, material grade and certificates, joint preparation, fit-up, preheat equipment, and access.
- During welding: check WPS variables-process, filler, current/voltage or wire feed, travel speed, preheat and interpass temperature, root cleaning, backing, and sequence.
- After welding: perform visual inspection for profile, size, length, undercut, overlap, porosity, cracks, spatter, arc strikes, and distortion; verify repairs.
Worked example
A WPS requires 100°C minimum preheat. The welder starts at 65°C because the steel is only 12 mm thick. The inspector stops the work, applies controlled heating, verifies 100°C with a calibrated contact thermometer, and records the reading. Reasoning: minimum preheat is a WPS variable that affects cracking risk; “it feels warm” is not evidence. Welding resumes only after the measured value meets the WPS.
Traps
- Treating a welder qualification card as a substitute for the WPS.
- Measuring fillet leg when the drawing specifies effective throat, or vice versa.
- Missing arc strikes, temporary weld removal, and crater cracks.
- Accepting a repair without re-inspection.
- Using an obsolete WPS revision.