An investigation of the role of secondary carbide in martensitic steel during three-body abrasion wear

High carbon martensitic steel specimens with various volume fractions of secondary carbide, ranging from 1.3% to 9.8% were obtained by changing the carbon content and air-quenching from the same reaustenitizing temperature. The carbon contents in the martensitic matrix of the steels were determined using a computerized X-ray diffractometer and were almost constant. The effect of volume fraction of secondary carbide on the three-body abrasion wear resistance of martensitic steel was investigated in a low-speed grinding system using silica and glass sand abrasives which had different sizes. It is shown that separate secondary carbide, which could increase the hardness of the steel, not only did not increase the steel's microcutting wear resistance because of the “size effect” but also decreased the wear resistance because of easy spalling. However, the micropitting wear resistance of martensitic steel could be improved by the separate secondary carbide. The role of secondary carbide during three-body abrasion depended on the hardness and size of abrasives used, which could significantly change the wear mechanism.