石墨形态和铬含量对铸铁干摩擦学性能的影响

Influence of Graphite Morphology and Chromium Content on Tribological Properties of Cast Iron under Dry Sliding

使用ＭＭ—２００磨损试验机研究了石墨形态和铬含量对铸铁与石棉基摩擦材料配副时的干摩擦学性能。结果表明，蠕墨铸铁的磨损率最低；摩擦系数由高到低依次为：片墨铸铁、蠕墨铸铁、球墨铸铁。蠕墨铸铁中，随着铬含量的增加，耐磨性能明显提高，摩擦系数略有降低。在高速、高载荷条件下，铬含量的质量分数达到１．５％时，耐磨性可达普通蠕墨铸铁的４倍以上；随着载荷的增加，蠕墨铸铁的摩擦系数降低，磨损率提高。在高速条件下，摩擦系数降低的幅度比在低速条件下小。铬改善蠕墨铸铁干摩擦学性能的效果在高速使用条件下更为突出。

The influence of graphite morphology and chromium content on tribological properties of cast iron against asbestos base frictional material under dry sliding was studied by MM 200 wear tester. The experimental results indicate that the cast iron with vermicular graphite morphology possesses the lowest wear loss rate. The friction coefficient of the grey cast iron is the highest, while that of the spheroidal graphite cast iron is the lowest. The addition of chromium to vermicular graphite cast iron made its wear resistance increase greatly and its frictional coefficient decrease slightly. Especially, under the condition of high sliding velocity and high contact pressure, the wear resistance of vermicular graphite cast iron with 1.5 % of chromium is 4 times higher than that of common vermicular graphite cast iron. With the increase of contact pressure, the wear rate increases and the frictional coefficient dicreases. The decrease of the frictional coefficient with the increase of contacting pressure is smaller at high sliding velocity than at low sliding velocity. The improvement on tribological properties due to addition of chromium to vermicular graphite cast iron is more obvious at high sliding velocity.