Influences of graphite shapes on wear characteristics of austempered cast iron

Dry slip-rolling contact wear test and wet slip-rolling contact fatigue tes t of several austempered cast irons with various graphite shapes were condu cted by using a Nishihara-type wear-testing machine. The influences of the graphite shapes on the wear and fatigue characteristics of cast iron were i nvestigated. Changing graphite shape from spheroidal to flake was found to result in a considerable increase in wear loss in both dry and wet conditio ns. Decrease in graphite nodularity results increase in wear loss at the in itial wear stage. It is because lower graphite nodularity results in a shor ter average matrix distance between graphites and also a larger stress conc entration factor at graphite tips. The pitting phenomenon is easier to occu r in sample with lower graphite nodularity. (C) 2001 Elsevier Science B.V. All rights reserved.