Abrasion resistance and micromechanisms in conventional and nonledeburitic high-speed steels

Micro-scale abrasion tests were performed using the ball-cratering method where a firmly clamped steel ball rotates against a specimen in the presence of abrasive particles. Such a design, together with loading of the sample by a dead weight, provides accurate control of the normal load and sliding distance. The diameters of resulting wear craters generated during the test enable calculation of wear coefficients using a formula equivalent to Archard's model of sliding wear. Commercial HS 6-5-2 steel was compared with the nonledeburitic steels containing high fraction of MC type carbides of titanium and/or niobium. The worn scars were investigated using a field emission SEM, which revealed the wear damage, typical for a three-body, non-directional abrasive mechanism. The calculated wear coefficients of the nonledeburitic alloys proved to be lower in comparison with the investigated conventional steel grade.