Stud-bolt failure

The alert mechanic informed the operations supervisors of the failures. Operations shut down the furnace. Maintenance mechanics replaced the bolts with the properly-specified high-strength stud bolts prior to any serious releases. 

This occurs when the bolt/stud is stretched and contracted with each pulse if the bolt/stud is not pre-stretched it will fail. Improperly torqued bolts on a gasket head can lead to catastrophic failure. 

Bolted joints are subject to cychc changes in forces that want to pull the joints apart. That s why all threads in a stud and nut are required to assure full performance of the connection. Missing threads put excessive stress on the remaining threads which can lead to their pressure failure. 

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