Verschleißfestigkeit und mikromechanismen in konventionellen und ledeburitischen schnellarbeitsstählen

Abrasion resistance is an important feature of high-speed steels (HSS) tribological profile. This characteristic depends on material bulk properties, mainly hardness, as well as microstructure. Nonledeburitic high-speed steels differ considerably from conventional grades with respect to the carbide phase content and proportions of MC, M₂C, M₆C and M₂₃C₆ particles. 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 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.