The development of surface structure of a crankshaft bearing

In this study, six crankshaft bearing materials were developed as alternative to conventional crankshaft bearing materials that are used in internal combustion engines and wear behaviour and friction coefficient of zinc based bearings with new formulation and original bearings was experimentally investigated. As a bearing, 6LD400 Lombardini brand crankshaft bearing was used. Crankshaft bearings are exposed to different effects of loads and strenghts. Six alloys like Zn-Al-Cu-O-C with different combinations that can adapt to these hard conditions were coated on the surface of aluminum alloyed bearing by atmospheric plasma spray coating method.Wear behaviour of bearings was investigated on ring on ring wear testing apparatus. As the wearing material, by taking a sample from newly-produced bearing and original bearing and as the abrasive material by taking a sample from the crankshaft bearing, the surfaces of wearing material and abrasive material were operated reciprocally.On the testing apparatus, for every sample throughout 1690 m wearing distance, 42N,67N and 92N loads were applied per load for 30 minutes with 300 rpm. In every 30 minutes, the testing apparatus was stopped and the sample was detached then it was weighed and the weigh loss was specified. During the experiment, friction force values of the samples were taken and with the available formula, the friction coefficient of the samples were found.From the surface of coated bearings and original bearing that worked before and after the wear testing, SEM (Scaning Electron Microscopy) images were taken and their microstructures were interpreted. Also, by doing EDS (Energy Dispersive Spectrograpy) analysis their elementary structures were investigated. The results of X-Ray analysis of the samples and EDS analysis were compared and their microhardness were examined. According to the findings obtained, the wear resistance of the bearings that were produced were higher than the original bearings.Keywords: Crankshaft Bearings, Zn, Atmospheric Plasma Spray, Wear