Evaluation of tungsten effect on the structure and properties of sHSS steel

The article presents the study results of experimental roll steel for the working layer of a two-layer roll. Reliable and durable operation of the roll in the rolling mill stand is ensured by the hardness, wear resistance and heat resistance of the working layer material. The research on the influence of tungsten on the heat resistance, hardness, and wear resistance of roll steel was carried out. With the thermal analysis, the temperature intervals in which the carbide phase dissolves, as well as other physical and chemical processes associated with heating the alloy, are determined. Thermal effects that were revealed during thermal analysis, indicate the presence of type I and II carbides in the experimental alloys, and also make it possible to determine the temperature intervals of their dissolution during the heating and holding the roll in a thermal furnace. It was established that during heat treatment, type II carbides do not dissolve in a solid solution that explains their presence in the structure after heat treatment and in the direct formation of finished product properties. The experimental alloy doped with tungsten within 1.0 % has the greatest heat resistance. This tungsten concentration provides the optimal grain size and amount of carbide phase in the alloy structure, which is often the cause of cracks during thermal cycling. The parameters of the carbide phase are determined at which crack formation is excluded during thermal cycling of experimental steel. The influence of tungsten on the wear resistance coefficient of experimental roll steel is determined. Tungsten carbides have greater hardness than chromium and molybdenum carbides, thereby increasing the wear resistance of the alloy as a whole. The work was carried out within the framework of the UIREC project “Advanced Production Technologies and Materials”, project No. 2022-26.