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 a-phase brass to
cast the propeller. Compare to the a+~ phase brass, the a-phase brass has less tensile
strength and hardness. The a+~ 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"/o Zn. The hardness value
for the fuiled 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 a+~ phase
brass