The expert system developed in the present work analyses the common defects in the ductile iron castings, steel forgings and weldments for their characteristics, causes and remedies. The defect analysis system has been built using the VP-EXPERT tool. A friendly environment has been created for the user by developing an attractive user-interface that tries to simulate actual human-interactions vis-a-vis, data interpretation, diagnosis, monitoring, planning, prediction and design. The knowledge base is open to further additions and modifications.