Visual examination and metallurgical examination are both important steps in obtaining physical evidence. Explain why visual examination needs to be performed prior to metallurgical examination. List four objectives of visual examination.
Visual examination objectives:
1. The manner of deformation, whether caused before or during failure.
2. The presence of wastage and degradation, whether from normal wear and tear, abuse in service, corrosion, or erosion.
3. The fracture characteristics, whether caused by ductile, brittle, fatigue, or other mechanisms.
4. Locations of crack initiation where fracture/failure had been preceded by cracking.