Recent Investigations - Plant Accidents

 Internal Corrosion of a Pipe Nipple Accident

Metallurgical failure analysis was requested following the failure of two high-pressure rupture discs at a chemical plant resulting in an atmospheric discharge of chemicals.   After extensive metallurgical  investigation, it was determined that a steel threaded pipe nipple that attached a pressure gauge through a thread-o-let to a diluent line had failed. This pipe nipple failure occurred due to extensive internal corrosion of the internal pipe surface. The pipe, whose wall thickness was reduced by threading, was corroded fully through the pipe where the nipple threads had already reduced the pipe wall thickness. A polished cross section of the threading on the end of the pipe as shown in photograph A.


Photograph A: Polished section showing reduction of pipe wall thickness where threaded nipple was threaded into a thread-o-let.

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Dr. R. Craig Jerner, Ph.D., PE specializes in accident investigation and metallurgical failure analysis, with over 30 years experience as a metallurgical consultant and accident investigator. He has testified as a metallurgical expert in over 250 depositions and more than 70 court appearances. If you or someone you know should need the services of  Dr. Jerner and J.E.I. Metallurgical, please visit our web site at the buttons below, or e-mail Dr. Jerner --- r.c.jerner@metallurgist.com


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