No abstract

Spalled fragments from work rolls of a steel bar straightening machine were received for failure analysis. Visual inspection coupled with optical and scanning electron microscopy (SEM) were used as the principal analytical techniques for the investigation. Fractographic observations clearly revealed the presence of a characteristic fatigue crack propagation pattern (beach marks) and radial chevron marks indicating the occurrence of final overload through a brittle intergranular fracture mode. The collected evidence suggests strongly that surface-initiated cracks propagated by fatigue mechanism led to spalling, resulting therefore in severe work roll damage and subsequently high machine downtime and maintenance costs.

No abstract

No abstract

A fractured extruded brass (CuZn39Pb3 alloy) hexagonal rod of 6 mm across flats (AF) was received with the request to perform a failure investigation. Visual inspection, and optical and scanning electron microscopy/ local elemental x-ray analysis (SEM/EDS) were used as the principal tools for the investigation. Metallographic and fractographic observations indicated the occurrence of brittle intergranular fracture. The collected evidence suggests that hot shortness is the failure mechanism.