Crack damage in a brass fitting

A metallurgical investigation revealed that a defect found in the bend of a leaking brass fitting was a result of stress corrosion cracking (SCC). The principal cause of the failure is shown to be the presence of significant SiO2-inclusions found in the threaded part of the fitting which led to pree xisting crack. The increase in stress at this crack-like defect led to the initiation of SCC. The failure is a typical example of the cumulative actio n of a number of damage mechanisms.