Recent Investigations - Industrial Equipment Accidents

General Industrial Equipment Failures   

Tractor Seat Failure

Metallurgical failure analysis was requested on a failed seat from a piece of heavy industrial equipment.  Examination revealed that some of the bolts attaching the seat to the tractor had failed.  Further investigation proved that not all attachment bolts had been in place when the seat had failed. The bolts that were in place were not adequately tightened.  The cause of the failure was found to be inadequate maintenance on the part of the tractor owner or operator.

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Mower Blade Failure

     Metallurgical failure analysis was requested in the failure of a large piece of industrial equipment.  During routine use, a wear plate separated from its support and was entrapped in the equipment.  Visual examination showed that the cause of the plate falling off was the failure of several retaining bolts.  These fasteners were found to have failed from overload stresses.  One fastener head was sheared off at the chamfer seat.  Visual and metallurgical examination revealed evidence that not all fasteners that were necessary to hold the plate in place were present at the time of the accident. 

     The cause of the failure was determined to be inadequate maintenance performed by the owner/operator in not insuring all fasteners were in place and tightened before operating the equipment.

Tree Mulcher
Photograph A: Large tree mulcher involved
 in the subject failure.

Jam between hammer mill and debris gate.
  Photograph B: Wear plate jammed between
hammer mill and debris gate.

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     Metallurgical failure analysis was requested after a large grass mower blade failure.  Macro and microscopic examination along with metallurgical analysis of the failed blade revealed that cracks introduced during the heat treating process were to blame for the failure.  The cracks during heat treatment were due to poor quality control on the part of the mower blade manufacturer.

Mower Blade - Microscopic Photo A

Mower Blade - Microscopic Photo B

Mower Blade - Microscopic Photo C

 

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Updated 7/5/11