Abstract
The effect of the chemical composition of BA1055 bronze on the mechanical properties has been investigated. It is important problem because many ship's sand cast propellers are made of this alloy. Properties of over one hundred melts were analyzed. The metallographic investigations were performed on the samples taken from five sand cast bars. It was shown that even small changes in chemical composition can significantly alter the mechanical properties of BA1055 bronze. The effect of intermetallic κ-phase, i.e. its chemical composition, shape and dimensions of precipitates, seems to be the most important.