Failure investigation of an industrial crankshaft made of ductile iron

The design against fatigue of materials and components in rotary equipments is critical and attractive, as number of industrial rotary components failed by fatigue increased over the years in petroleum sector. Novelty of fine grain practice micro structure engineering and surface modification/surface engineering significantly increases the fatigue strength of industrial components. Root cause analysis of fatigue failure is conducted with possible outcome to prevent the failures. The high cycle fatigue life design of crankshaft approaches safe life design philosophy. In the present investigation, failure analysis of the crankshaft was analyzed to determine the cause of failure. Visual examinations reveals the brittle fracture with beach marks and metallographic examinations reveals the crack initiation at Type I graphite sharp boundaries in pearlitic matrix and crack propagated & accelerated till broken in to two pieces of crankshaft