A worker was severely injured when he sat in a chair collapsed in the crew meeting room of a cargo ship. The photographs below were taken for the visual examination.
Photograph 1 Subject chair and failed chair leg.
A weld securing the chair leg to the chair seat failed and is shown in Photograph 2.
Photograph 2 Subject left front chair leg.
Photograph 3 shows a side view of the chair leg weld. It should be noted that the chrome plating was not removed from the chair leg prior to welding. Removal of chrome plating prior to welding or rewelding is required to produce a quality weld.
Photograph 3 Chair seat side of the leg weld failure.
The failed weld has large areas of porosity, slag entrapment and large regions exhibiting lack of fusion, as seen in Photograph 4.The failed weld has large areas of porosity, slag entrapment and large regions exhibiting lack of fusion, as seen in Photograph 4.
Photograph 4 The left front seat side showing the weld failure.
Close-up view from another perspective of the seat side of the chair leg failure is shown in Photograph 5. Regions of lack of fusion, improper preparation for welding and slag entrapment are all evident. The flat portion of the tube failure shows some fatigue crack growth in the chair leg tube prior to final collapse.
Photograph 5 Seat side of the failed left front chair leg weld failure.
In the close-up view of the failed left front leg, photograph 6 shows the seat section was not welded in the area between 7 o’clock and 11 o’clock. Also present is the fact that chrome plating from original manufacturer is evident and was not removed prior to rewelding. Residue chrome plating can introduce brittle components into the weld, thus making it susceptible to early failure.
Photograph 6 Left front leg side of weld failure.
Photograph 7 No evidence of welding is present from about 7 o’clock to 10:30 o’clock.
Base on the above visual examination only (no destructive testing was allowed) the following was concluded:
- Failure was the result of inadequate and improper rewelding of the subject left front chair leg to the chair seat
- The weld joint was improperly prepared. As can be clearly observed above in Photograph 6, the chrome plating was not removed from the original chrome plated leg weld and joint prior to rewelding.
- The reweld did not exhibit fusion or weld penetration over approximately 90° of the circumferential leg to seat repair weld.
- The inadequately and inappropriately rewelded chair leg failed as a result of progressive, long-term metal fatigue.
- Although the sea man was not “a small boy” the chair leg fracture surface visually revealed that the chair leg failure was not the result of a one-time overload stress.