Experimental investigation of thermo-mechanical properties of copper based marine propeller materials

Abstract

Marine propeller must have good mechanical properties to receive the torque developed by the prime mover and to transmit the same as thrust into water to ply the ship. While the ship is in service, its propeller may get damaged and then, a lot of money is required to get the defect rectified. As such, marine propellers are made of high quality cast materials having superior mechanical behavior along with required corrosion resistant properties. The susceptibility of the required material properties has relation to aging during prolong service period and cavitation occurring while the propeller is rotating at a higher speed. Therefore, this paper is an attempt to characterize few such properties as the function of aging condition and time. In this regard, commonly used copper based propeller materials have been undertaken to carry out the experiments and found that the micro-hardness, resistivity, tensile strength and elastic modulus are reduced for elevated temperature, but not exactly with the rise of aging time. In few cases, fluctuating behavior has also been observed in the copper based propeller materials undertaken in present work.