Fatigue Life Evaluation of Weld Surfacing LB 52 Grade

Abstract

The damage to the propeller shaft, a principal mechanical component in the power transmission system of Boats makes engines work harder than normal attributed to less transmission efficiency. Operating boats with the damaged propeller shaft increases the rate of fuel consumption per distance and cost of fishing which affects income of coastal fishermen. The result of a preliminary survey of Boats at Kaoseng Community revealed that the service life of the damaged propeller shafts caused by the fatigue failure would be repaired by shield metal arc welding process. The statistical analysis showed that the useful life depended on fatigue endurance limit of welding surface. When they were back to be used again. The objective of this research was to study the fatigue life of hardfacing surface by solid wire. The method of this research included (a) building up the hardfacing surface (b) forming specimen from hardfacing surface and (c) finding out the fatigue life by fatigue testing machine base on ASTM E739-91 standard. The results of this research indicated that hardfacing surface by solid wire could not receive fatigue stress exceed 500 MPa. The propeller shafts after being repaired will have very short service life, which is not feasible in engineering economy.