Research On Surface Morphology And Microstructure Evolution Of Cylinder-piston Ring Group Based On Friction And Wear Behavior

Cylinder liners and piston rings are the important friction pairs in internal combustion engines.Their wear performance will directly affect the reliability and service life of internal combustion engines.Therefore,improving the wear resistance of cylinder liners and piston rings is of great significance for improving the performance of internal combustion engines.At present,the cast iron is the mainly materials of cylinder liner.So,from the perspective of materials science,this article proposes a method to improve the wear resistance of cylinder liner materials in view of the wear problems of the cylinder liner during actual service.Based on the research on the wear resistance of cylinder liner cast iron materials with different composition,the change of the microstructure and morphology of the cylinder liner cast iron material during the friction and wear process and the influence of different tissue composition on the wear resistance are analyzed.So as to provide data support for the organization optimization and design of the cylinder liner cast iron material.The composition of the five types of cylinder liner cast iron materials were firstly analyzed in this article,and the interpolation method was used to characterize the microstructure hardness distribution of the cast iron materials.At the same time,a rough surface morphology with certain processing and organization characteristics was established from different scale factors.The finite element software was used to simulate the friction process of cast iron materials.The results show that the cracks in the wear process of cast iron materials are mainly generated near the graphite structure,and the crack growth is affected by the graphite morphology.The morphological changes during the wear process are mainly affected by the matrix structures.The pearlite structure is usually in the position of rough peaks,while graphite and ferrite form depressions.The analysis of the wear scar and wear debris morphology of several cast iron materials shows that graphite is first worn away during the wear process,followed by the matrix structure around graphite,and pearlite is more difficult to be worn than ferrite.At the same time,the correctness of the simulation calculation results has also been verified.The friction and wear experiments of five cast iron materials at different temperatures and rotation speeds were performed.The analysis of the wear resistance,microstructure and morphological evolution of the five materials under different conditions shows that pearlite-based cast iron has better wear resistance at room temperature.With increasing temperature,wear resistance and surface morphology are mainly affected by graphite morphology and pearlite lamellar spacing.Ductile cast iron has poorer wear resistance than gray cast iron and vermicular graphite cast iron.The larger the pearlite layer spacing,the worse the wear resistance,and the rougher the surface topography.The influence of the speed on the wear resistance of the cast iron material mainly depends on the graphite morphology、the matrix structure and the lamellar spacing of the pearlite.With the increase of the speed,the wear resistance of gray cast iron decreases.The wear resistance of ferritic base cast iron is superior to pearlite-based cast iron at low speeds,and its surface morphology is more uniform.The larger the pearlite lamellar spacing,the more prone to fatigue wear at higher speeds and the rougher the appearance of the wear scar.