Analysis Of Tool Wear In Cgi Machining

In this study the tool wear and wear mechanisms on coated cemented carbide inserts were investigated in turning of Compacted Graphite Iron (CGI) materials with different nodularity. Investigation of how small changes in nodularity affect the wear behaviour of inserts in CGI machining has not earlier been done. The inserts were examined in LOM, SEM and in EDX. The tool wear could on the basis of their wear appearance be classified in three different wear categories; A, B and C. In the wear category A, abrasive wear, adhesive wear and delamination wear could be seen. In the wear category B, the predominant wear mechanism was chipping. The wear appearance in wear category C indicated attrition wear and dissolution via diffusion. Classification of the wear mechanisms gave knowledge that could be used in tool design. The results showed that increasing nodularity has impact on wear at moderate and high cutting speed but not at lower cutting speed. Machining of all materials at high cutting speed, 400 m/min, led to complete degradation of the edge line. A small difference in nodularity from 5% to 20% has more significant impact on wear than from 20% to 62%. This seemed to be correlated with the difference in ultimate tensile strength between the materials.