Failure analysis of lead-free brass valve bodies

This paper presents the failure analysis of the lead-free brass valve bodies that had been installed in plumbing sanitary equipment. Leakage points were found adjacent to the brazing location. Visual inspection, stereomicroscope and scanning electron microscopy coupled with an energy dispersive spectrometer (SEM/EDS) were used as the principal analytical methods for the present failure analysis. The analysis results implied that the combined action of excessive brazing residual stresses and bismuth boundary segregation was probably responsible for the failure of lead-free brass valve bodies. Finally, two important suggestions were proposed to minimize the risk of recurrence of the present leakage failure in the future.