Failure crankshaft

MAIN CRANKSHAFT FAILURE IN TRANSAMERICA DELAVAL EMERGENCY DIESEL GENERATORS... 

The first involves the misapplication of chromium electroplating to an engine crankshaft during a rebuild procedure, which resulted in a fatigue failure shortly after the unit was put back into service. 

Failure Investigation. The crack shown in Figure 7.42 had propagated through almost the entire cross-sectional area of the crankshaft web. The remaining ligament was broken open to expose the crack faces where, as is shown in Figure 7.43, it became readily... 

Wet fluorescent magnetic particle inspection of the remaining journal fillets on this crankshaft revealed the presence of a number of secondary cracks in the same orientation and position as the failure initiation site. A metallographic specimen, including the matching halves of the fracture from the initiation site in the fillet of main journal, was cut, mounted, polished and etched in 2% nital, in preparation for examination with an optical microscope. The polished and etched specimen is shown in Figure 7.44. 

Hutchings, F.R., Unterweiser, P.M. (Ed.) Eatigue failure of a diesel engine Crankshaft, from Eailure Analysis the British Engine Technical Reports. ASM (1981)... 

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