Cast alloy steel grade 35KhGSL is widely utilized in various industries. Sometimes, wear resistance and hardness become highly essential for different machine parts. Additions of ultradispersed powders in melt as modifiers, external impact on crystallizing alloy are two important approaches to enhance the mechanical characteristic. In this work, a combination of ultrafine modifier in the form of titanium carbide TiC and mechanical vibration was used for the first time on cast alloy steel grade 35KhGSL in order to study changes in hardness and wear resistance. The method of introducing a modifying additive into the melt is indicated. The analysis has been carried out based on hardness, tribological properties, and microstructural characterization. The microstructural was analyzed using metallographic microscope and scanning electron microscope (SEM) analysis. In addition, the Vickers microhardness values were measured, and dry abrasion test was conducted to check the steel's variation in hardness and tribological characteristic after treatment. The combination of mechanical vibration of the crystallizing melt with the simultaneous introduction of titanium carbide powder maximized the hardness of 285 HV (by 36%) and wear resistance. It was recommended to include modification and mechanical vibration operations in the production technology of the "Sprocket" casting at the Parkhomenko Foundry Machine-Building Plant (Karaganda, Republic of Kazakhstan). This type of casting is used in conditions of intensive wear.

This study aimed to improve the hardness and wear behavior of medium-carbon alloy steel through the addition of titanium carbide ultradispersed powder and low-frequency vibration treatment during solidification. It was shown that the complex effect of low-frequency vibration with the additional introduction of a small amount of titanium carbide ultradispersed powder with the size of 0.5–0.7 μm during the casting process had a positive effect on structural changes and led to improved mechanical properties, and so increasing the value of microhardness by 37.2% was notable. In the process of shock dynamic impact, imprints with crater depths of 13.69 µm (500 N) and 14.73 (700 N) were obtained, which, respectively, are 23.34 and 42.34% less than that on the original cast sample. In the process of tribological testing, decreasing the depth of the wear track (50.25%) was revealed with decreasing the value of the friction coefficient by 14.63%.

The authors studied the influence of Mo and C on the properties of the CoCrNiFeMnNb alloy system. Quasi-high-entropy alloys (QHEAs) were smelted by partially using ferroalloys in the charge, unlike classical high-entropy alloys (HEAs). The Mo content was 2 and 4% mass. The C content was 0.45% mass in the experimental alloys. The C content was determined based on the initial content in the charge. The experimental alloy microstructure was represented by a solid FCC-type solution; Laves phases of various compositions; Me1Me2-type intermetallics; carbides Nb0.8, Cr0.2C, and Mo0.5NbC; and μ-phase NbCo2. All experimental alloys had higher hardness, strength, and wear resistance than the alloy without Mo and C. Increasing the Mo content in the alloy to 4% mass increased the hardness and, in particular, the wear resistance of the alloy. Strengthening the alloy with elements Mo and C is associated with forming a finer grain. Grain growth was limited by implementation phases, as well as dispersion strengthening due to solid implementation phases of various origins being formed.

The influence of the carbonitration medium on the distribution of chemical elements (C, N) and the change in microhardness over the depth of the surface layer formed during carbonitration is considered. The carbonitration operation was performed in 2 stages. During the first stage, cementation was performed at a temperature of 950°C for 40 minutes in a C2H2 medium at a flow rate of 0.5 to 3.0 liters per minute. During the second stage, nitriding was performed in N2 medium at a temperature of 850°C for 40 minutes at a constant nitrogen consumption of 1.5 liters per minute. Steel grade 20CrMo was used as the object of the study. It was shown that the carbonitration process of 20CrMo steel followed by high-frequency current quenching led to a significant increase in surface hardness. The distribution of chemical elements over the depth of the surface layer is not uniform: the carbon content changes gradually over the depth of the surface layer, while the presence of nitrogen is not fixed already at a depth of 200 μm.