Who you Calling Complacent
After 15 years in NDT and 'substantial' experience in performing MPI with AWS D.1.1 as the fabrication code/acceptance criteria, one would think weld inspection would be so easy when using an AC yoke - Wet Black ink with paint primer as background.
At least 20 hrs had been spent on inspecting a specific component that comprised of two plates welded together with inserts to form a flattish box; pretty routine - no challenges.
After inspecting a small number of boxes, the tech was packing up his equipment when was called to the hydrostatic pressure testing bay. While approaching one of the boxes in the bay, he noticed that a small stream of water was spouting from a hole in one of the welds. On closer inspection (pun intended), an isolated pore (pipe/wormhole?) was identified, approximately 1.5mm ⌀ in the center of one the longitudinal weld caps. A missed defect! It looked as if someone had drilled a hole right through the weld past the root into the cavity of the box.
OK, so, what now? The customer was pretty bemused - the end user's inspector? - More so (fortunately). A bit of what if... and troubleshooting happened thereafter.
The following factors that could of contributed to the missed defect where extrapolated:
- Did the tech experience a brain failure?
- Was he over familiar with the technique?
- Was the component placed too close to the floor? Uncomfortable tech body position?
- Was the tech tired?
- Was the tech in a hurry to finish?
- Was the defect easy to find with the technique that was used?
- A combination of the above?
It was concluded that a combination of the above was the most likely cause.,/p>
What prevented an unpleasant situation from occurring where the repercussions could have meant a recall of all previously inspected boxes, loss of a customer and contract, was that the technician had been courteous prior to and during the missed defect situation. He did not react by saying - 'It wasn't me' or try to blame his boss; equipment; the dog and everyone else, except himself.
A bit of respect, prudence, and general manners goes a long way towards ensuring that you are requested by name to do repeat work for your customer.