Cross-scale influence of heat treatment-induced microstructure evolution on the gradient temperature wear mechanism of tungsten T15 high speed steel

Abstract Microstructure and fracture mechanism for electroslag remelting (ESR) + rolling + annealing T15 high speed steels (HSS) strengthened by different heat treatment systems were compared with those of the sample that was not heat-treated. Their wear behaviors using Si 3 N 4 ball counterface at room temperature and high temperature were also investigated, respectively. The results showed that volume fraction and sphericity of carbides were decreased and increased after heat treatment, respectively. It displayed quite different fracture mechanisms between unheat-treated and heat-treated samples. And it also showed completely diverse wear properties and behaviors for the samples after heat treatment whether at room or high temperature. The strengthened wear properties are attributed to the improvement of characteristics for the carbides and matrix caused by heat treatment. Besides, the surface of Si 3 N 4 is mainly worn by abrasive wear at room temperature, while almost no wear on that of Si 3 N 4 at high temperature. There chiefly occurs ploughing wear accompanied by oxidative wear for HSS at room temperature, but the surface of HSS is principally worn by oxidative wear accompanied by adhesion wear at high temperature.