Failure analysis of a lead-free brass tap used in potable water

• Crack formation was attributed to the micro segregation of bismuth.
• The cracks formed will propagate through the grain boundaries.
• The cracks were a typical intergranular failure.

In this case study, the failure cause of a lead-free brass tap was investigated. The features of cracks were carefully studied by macroscopic inspection, chemical analysis, optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The analysis results showed that the micro segregation of bismuth in the failed lead-free brass tap was considered as an important reason for crack formation. Further examination indicated that coarse bismuth rich phases were distributed mainly along grain boundaries. The cracks were found to be a typical intergranular failure, which revealed brittle fracture for the failed lead-free brass tap. It is expected that this work may help reduce the incidences of failures during the productive process of the lead-free brass taps.