Effects of titanium content on the impact wear properties of high-strength low-alloy steels

In this study, the mechanical properties, wear behavior, and microstructures of high-strength low-alloy steels with titanium contents of 0, 0.04, 0.1, and 2 wt% were systematically investigated. Steel microstructures were examined via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The wear properties of the steel samples were evaluated by measuring their weight losses, while the wear mechanism was elucidated via scanning electron microscopy. The worn steel surfaces exhibited very rough topographies with well-defined craters and grooves, which were produced by high-angle and low-angle impacts, respectively. The wear resistance of the steels strongly depended on their microhardness and impact toughness. Compared with the other steel specimens, the steel with 0.04 wt% titanium, which contained martensite and lower bainite particles, possessed superior mechanical properties, i.e., a hardness of 745 HV and an impact toughness of 97 J/cm3. Meanwhile, the steel with 2.0 wt% titanium exhibited the lowest abrasive resistance, impact toughness, hardness, tensile strength, and yield strength among all the specimens. These results indicate that excessive titanium content promotes the precipitation of large particles in the steel matrix, which degrades its mechanical properties.