Investigation of Wear Behavior and Diffusion Kinetic Values of Boronized Hardox-450 Steel

Hardox steels are widely used in the industry as they have many excellent mechanical properties besides good wear resistance. In this study, Hardox-450 steel was boronized at different temperatures (1123, 1173, 1223 K) and holding times (2, 4, 6 h). Following the boronizing process, the morphology of the boride layers formed on the steel surfaces was examined by SEM microscope. Hardness values were measured with microhardness device and phases formed on the layer were analyzed by X-ray diffraction technique. XRD analysis showed that a layer of boride consisting of the Fe2B phase was formed as a single-phase structure. It was also observed that the thickness of the boride layer obtained in boronized Hardox-450 steel increased with the increase in the boronizing time and temperature. While the original hardness values of Hardox-450 steel were 430 HV0.05, as a result of the boriding process, it reached up to 1880 HV0.05. The thickness of the boride layer on Hardox-450 steel and growth kinetics of boride layer were also examined. The activation energy (Q) of boronized Hardox-450 steel was determined as 157.990 kJ/mol. Wear tests were carried out using a ball-disc wear method at a sliding speed of 0.3 m/s under a load of 10 N in a dry environment and at a sliding distance of 500 m. Adhesion properties of the boride layer were examined by Daimler-Benz Rockwell-C indentation test. Wear resistance increased with boriding process. It has been determined that the wear and adhesion resistance decrease with the increase of boronizing temperature and time.