Stress Corrosion Cracking in "Lead Free" Brass

The effort to reduce lead in the water supply by the Federal Safe Drinking Water Act has resulted in a search for brasses without lead for use in plumbing components. “Lead free” C693 silicon brass is an alternative to the C360 leaded brass that had been the standard for plumbing components for many years. Failure analysis of a ½ inch plumbing component fabricated from C693 “lead-free” silicon brass revealed the failure mechanism to be stress corrosion cracking (SCC). Contributing factors included microstructural variation and banding throughout the thickness of the plumbing component. In addition, a high level of residual stresses from the fabrication of the raw material hex bar was noted.