Study On Tribological Behaviors Of Cast Irons Against Gcr15 Steel Under High Speed Dry Sliding Condition

The tribological behaviors of cast iron of different graphite morphology and matrix structure (dry sliding against GCr15 steel) were investigated on the MMS-ⅠG high speed under the conditions of velocity (10~90m/s) and contact load (0.33 and 0.67MPa). At the same time, with the help of Microscope, SEM, EDAX, tribo-metallographic phases, the microstructure and morphologies of worn surface had been studied. The relation-ship between tribological behaviors and friction surface features were discussed.The results indicated that friction coefficient of cast irons declines with the increase of sliding velocity. The wear rate increases in general as the the contact load is 0.33MPa while it declines as the contact load is 0.66MPa with the increase of sliding velocity.Graphite morphology and matrix structure have an obvious effect on friction and wear characteristics of cast irons. Due to thermal conductivity superior to spheroidal graphite cast iron and graphite morphology on the impact of the matrix structure better than ?ake graphite cast iron, compacted vermicular cast iron has good tribological properties. Friction coefficient and wear rate decline with the increase of pearlite content. Matrix structure has an insignificant effect on the friction coefficient of cast iron, but has a greater impact on the wear rate.Because of the difference of the graphite morphology and matrix structure of cast iron, the wear mechanism is different. The wear mechanisms of ?ake graphite cast iron is mainly abrasive wear; that of compacted vermicular cast iron is mainly abrasive wear and oxidative wear; that of spheroidal graphite cast irons is mainly abrasive wear and oxidative wear and spalling wear. The wear mechanisms changed from abrasive wear to abrasive wear and oxidative wear with the increase of the content of pearlite, the level of oxidative wear increased.