Cavitation Failure of Local Made Propellers and Suggestion for Improvement

Cavitation is a normal phenomenon for a propeller and its presence indicates the loss of its usefulness. For the failed propeller, effect of cavitation is due the poor material in term of its hardness and strength. The local foundries produced α-phase brass to cast the propeller. Compare to the α+β phase brass, the α-phase brass has less tensile strength and hardness. The α+β brass can be produced by having a chemical composition of 60 wt% Cu and 40 wt% Zn. The investigation shows that the chemical composition for the failed propeller contains only 31.38 wt% Zn. The hardness value for the failed propeller and new developed material are found to be 97.06HV and 178.64HV, respectively. In improving the material properties with respect to the effect of cavitation on propeller the local foundries is suggested to cast α+β phase brass.