Friction And Wear Properties Of Chrome-plated Cylinder Liner Under Reciprocating Sliding Condition

Nowadays, cylinder liner and piston ring are working in more severe conditions with the development of the engine, which lead to improve the comprehensive properties, such as wear resistance and anti-adhesion. Therefore, the research about tribological characteristics of cylinder liner and piston ring should carry out to get rules and mechanisms of friction and wear in different conditions, for providing a theoretical basis about application and tribology design of cylinder liner and piston ring, which has important significance to improve tribology performance of the engine.In this paper, load-change experiment, wear test and starvation experiment have carried out, using a self-developed contraposition Reciprocating Test Rig with wear form-conditions simulation principle, to study tribological characteristics of chrome-plated cylinder liner, choosing piston rings of PVD chromium nitride coating and sprayed molybdenum coating as counterbody. Friction coefficient, wear and continued time from starvation to abnormal adhesion of two friction pairs have studied in different loads and temperatures, then mechanisms of friction, wear and anti-adhesion have investigated by analyzing surface morphology and chemical composition of tested specimens.The results showed that:(1)When the temperature is higher than 70℃,friction coefficient of chrome-plated cylinder liner and sprayed molybdenum piston ring declines with increasing temperature, while friction coefficient of chrome-plated cylinder liner and PVD chromium nitride piston ring decreases first, then has a upward trend.(2)Load is more obvious on wear increased than temperature. In the same working conditions, wear of chrome-plated cylinder liner with PVD chromium nitride piston ring is more serious than with sprayed molybdenum piston ring, but wear is both minimal.The wear mechanisms of chrome-plated cylinder liner is fatigue wear with stripping form.(3)When the load is less than 60MPa and the temperature is below 200℃, anti-adhesion of chrome-plated cylinder liner and PVD chromium nitride piston ring is better than chrome-plated cylinder liner and sprayed molybdenum piston ring. With increasing load and temperature, anti-adhesion of two friction pairs is degraded.The scuffing mechanism of chrome-plated cylinder liner and PVD chromium nitride piston ring is high temperature deformation locally, while chrome-plated cylinder liner and sprayed molybdenum piston ring is partial adhesion mainly.