Root Cause Failure Analysis of Castings: A Case Study of a Brake Rotor

Abstract

A premature failure of a vehicle brake rotor was investigated and reported. The brake rotor was manufactured from a grey cast iron material and had covered about 10 670 miles before it failed. The failure-generated tremendous concern for the autoparts manufacturer due to the warranty claims from the Original Equipment Manufacturer (OEM). This chapter, however, intends to describe the methodical approach used to identify the failure’s main cause using a root cause failure analysis technique and offer suggestions to prevent a similar failure from re-occurring. The results of this investigation showed that the disc’s early failure was caused by oxide inclusions that were accidentally entrapped into the disc’s neck region. The eventual disc failure was initiated by micro-cracks developed within the inclusion particles and propagated through the weakest interface between flaky graphite and the pearlitic matrix. To ensure that nonmetallic inclusions are kept out of cast components, several solutions for improving casting quality were proposed.