Friction and wear characteristics between cermet alloy and cast iron

Friction and wear tests between the TiCN cermet chip and FC250 cast iron ro ller have been carried out using a roller-chip type testing machine in air under unlubricated condition. The friction force-sliding distance curves we re obtained under the following test conditions: normal loads between 10N-3 0N, sliding speeds between 0.05m/s-0.3m/s, and a total sliding distance of 2000m. The friction force was affected by the sliding distance in the diffe rent manners depending on sliding conditions. The friction force-sliding di stance curves for the tests could be divided into three groups(type A, type B and type C), depending on the characteristic of the profile, especially in the early stage (similar to 500m in sliding distance) of each wear test. In type A, the friction force rapidly increased to a maximum value at the b eginning of a test, and then decreased to a certain stable value for the sl iding distance alter that. Ln type B, such rapid decrease in the frictional force after a maximum value did not appear, although sudden drops or rises were observed irregularly during the test. In type C, the friction force o nce decreased after the reaching to a maximum and again increased to a cert ain stable value for the sliding distance after that. The amount of a ear a fter the test was relatively large in the TiCN cermet chip for type B, but remarkably large in cast iron roller for type C. The origin of such three types of friction force-sliding distance curve and the tendency of wear in both chip and roller were discussed in related wit h the results of the sliding surface SEM observation and EPMA analysis.