The Research Related To Strengthened Surface Of Cylinder Prepared By High-Energy Ball Milling Method

This paper explores a new method—high-energy ball milling, to strengthen the surface of the cylinder, which can greatly improve the wear resistance and service life of cast iron cylinder liner by preparing micro and nano powder by ball mill after learning many other surface enhancing methods.In this study, the micro and nano powder of serpentine and SiC particles are prepared by the ball-milling, and the micro and nano material is impregnated on the inner-surface of the cylinder liner to harden the surface. Firstly, the basic parameters are determined according to the elastic-plastic contact theory proposed by Brizmer. Next, 12 cylinder liners of different materials, different ball-milling types and different milling time are prepared for the orthogonal factor by orthogonal test. In order to test the wear resistance of the cylinder, the performance of the cylinder under different lubricating conditions is analyzed by the friction and wear test, and the optimal solution is found out by optimizing the orthogonal factors. Finally, the mechanisms of hard impregnation and impregnation through soft channel are described theoretically by using scanning electron microscopy.The results of the test show that within the parameters'scope, the optimal wear-reducing result of the strengthened liner layer is achieved when the material is the serpentine, the milling type is wet, and the milling time is 10h. When the pressure is 40Mpa, under well-lubricated and high-speed condition, the final temperature of the friction pair is 65℃, the friction coefficient is 0.07 and the wear loss is 6.8mg. Compared with the original material, the result can be drawn that the friction coefficient could be reduced by 35%, and the wear loss could be reduced to 1/3 of the original under oil-rich condition; while, the friction coefficient could be reduced by 15%, and the wear loss could be reduced to 1/2 of the original under poor-lubricated condition. The microhardness of the liner surface is significantly increased approximately by 48% by strengthening.