Abrasive wear-microstructure interactions in a Ni-Cr white iron

The low-stress and gouging wear behavior of a series of Ni-Cr white iron (Ni-Hard 4) samples has been characterized. The samples were processed to contain 5–85% retained austenite in their microstructures so that their Rockwell C hardness ranged from 63 to 47. The low-stress abrasion behavior was measured with loose SiO 2 and Al 2O 3 abrasives in a rubber wheel test system. The gouging abrasion behavior was determined in a bonded Al 2O 3 wheel test system. Wear scars were characterized by scanning electron microscopy used in conjunction with energy dispersive X-ray spectroscopy. Both low-stress and gouging wear behavior were strong functions of test condition and microstructure, and weight losses passed through maxima or minima as the volume fraction retained austenite or abrasion condition varied. Carbides controlled wear behavior in the low-stress test against SiO 2, and their attrition occurred by uniform scratching, preferential chipping at leading edges and cracking-spalling. In low-stress and gouging tests against Al 2O 3 carbides and matrix underwent attrition by uniform micromachining. The test results indicated that retained austenite content could be used to optimize wear resistance in a variety of abrasion situations.