The friction between piston ring and cylinder liner was studied using the pin-on plate reciprocating tests. For this aim, cast iron cylinder liner was borided. The friction coefficients of normal and borided cylinder liners were measured in different reciprocating speeds. Frictional correlation of piston ring and cylinder liner was determined changing material properties of cylinder liner and crank angles of engine.

As a result of this study, the hardness of the surface has improved four times and abrasive wear resistance has increased. The roughness of the surface is decreased and a porous structure has been obtained. When the roughness is fallen, the friction coefficient is also diminished. Porous structure has increased oil-retaining capability. In case of mixed lubrication, the friction coefficient has become less at the section of metal-metal friction because of the hardness of the    surface. The friction tests indicated an important influence of the material property and the surface structure on tribology formation. Hydrodynamic lubrication feature has become more due to the porous structure. Consequently, wear and friction resistant of cylinder liner surface has been decreased by boronizing grey cast iron.

cylinder liner, piston ring, friction, boronizing.