Two-Body Abrasion Behaviors Characterization of White Cast Iron with Various Chromium Concentrations
Baochao Zheng, Jiandong Xing, Yangzhen Liu, Wei Li
Abstract
As-cast white cast iron specimens with chromium concentrations of 0, 2, and 4 wt% were prepared by melting and casting. Scanning electron microscopy and X-ray diffractometry results indicate that the composite phase consists of a hard phase (cementite) and a toughness matrix (pearlite) with a 28.8 ± 2% cementite volume fraction, which is a typical hypoeutectic structure. The cementite and pearlite microhardness increased with a higher chromium content. The maximum cementite microhardness was 1,054.23 HV. Two-body abrasive wear was measured under a higher impact load using a pin-on-disc tribometer. The effect of chromium content on the wear behavior of the cementite groove depth and width, roughness, chip peel off on the worn surfaces, and mass loss were investigated at an applied pressure of 1.83 MPa. With increasing Cr content, the roughness and mass loss decreased by 10.7 and 15.9%, respectively, and the wear resistance increased visibly. The break in abrasive SiO2 resulted in abrasive tip passivation during wear. As a result, the ratio of the depth–width of the parallel groove and the length–width of the worn chip decreased significantly.