This study forms part of the current research on modern steel groups with higher resistance to abrasive wear. In order to reduce the intensity of wear processes, and also to minimize their impact, the immediate priority seems to be a search for a correlation between the chemical composition and structure of these materials and their properties. In this paper, the correlation between prior austenite grain size, martensite packets and the mechanical properties were researched. The growth of austenite grains is an important factor in the analysis of the microstructure, as the grain size has an effect on the kinetics of phase transformation. The microstructure, however, is closely related to the mechanical properties of the material such as yield strength, tensile strength, elongation and impact strength, as well as morphology of occurred fracture. During the study, the mechanical properties were tested and a tendency to brittle fracture was analysed. The studies show big differences of the analysed parameters depending on the applied heat treatment, which should provide guidance to users to specific applications of this type of steel.

The article presents the results of Hardox Extreme steel tests in the as-delivered state from a steel mill (after quenching and tempering), and also in the normalized state. The research procedures included a microstructure analysis using light microscopy; and a static tensile test at ambient temperature to determine its Young’s modulus, yield strength, tensile strength, elongation and reduction in area after fracture. During the tensile tests, both the longitudinal and transverse orientation of rolling direction were taken into account. The Charpy impact test was also carried out in the temperature range of the ductile–brittle transition in connection with the fractographic analysis carried out with the use of a scanning microscope (SEM). The impact tests were carried out on samples in both directions on the plate, using the following temperatures: −40, −20, 0, +20 °C. Based on the structural and strength characteristics of Hardox Extreme steel determined on the basis of the research, in a further part of the paper the possibility of its use in machine construction elements operating in selected industrial sectors is considered/discussed, with a particular emphasis on reducing the level of energy consumption in the manufacturing and operation of the above technical facilities.

The paper presents the results of tests of a welded joint of Hardox 450 steel, belonging to the group of weldable high-strength boron steels with increased resistance to abrasive wear. As a result of the conducted research, apart from the basic structural indicators, an attempt was made to determine the correlation between the grain size of the prior austenite in the characteristic weld zones and its basic mechanical properties, such as yield point, tensile strength, percentage elongation after fracture, reduction of area, and impact strength. The scope of research quoted above was carried out for a welded joint of the considered steel at delivery state (directly after welding), in the normalising annealed state, as well as in water-quenched state, using different austenitisation temperatures in the range of 900–1200 °C. The results obtained showed a large influence of the parameters of the applied thermal heat treatment on the selected structural and mechanical properties of the welded joint.

This paper focuses on relationship between the mechanical properties and abrasive wear resistance, expressed by the K_b index, using an example of low-alloy cast steels. In order to achieve the aim of this work, eight cast steels of varying chemical composition were designed, cast and then heat treated. The heat treatment involved quenching and tempering at 200, 400 and 600 °C. Structural changes caused by tempering are demonstrated by the different morphologies of the carbide phases in the ferritic matrix. In the first part of this paper, the present state of knowledge about the influence of structure and hardness on the tribological properties of steels is discussed. This research involved the evaluation of a material’s structure, as well as its tribological and mechanical properties. Microstructural observations were performed using a light microscope and a scanning electron microscope. Next, tribological tests were carried-out with the use of a dry sand/rubber wheel tester. To determine the mechanical properties, Brinell hardness measurements and a static tensile test were carried out. The relationship between the determined mechanical properties and abrasive wear resistance was then investigated. The analyses also provided information regarding the heat treatment states of the analyzed material in the as-cast and as-quenched states. It was found that the abrasive wear resistance, expressed by the index K_b, was most strongly correlated with hardness and yield point. In addition, observations of the wear surfaces indicated that the main wear mechanisms were microcutting and microplowing.

In this work, the influence of chromium and titanium on the microstructure and mechanical properties of cast steel is investigated. The analysis was carried out on a material covered by patent Pat.243157. Advanced techniques were used, including dilatometric analysis, light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The material was examined in various states: as-cast, quenched, and quenched with subsequent tempering at 200?C, 400?C, and 600?C. Important mechanical properties such as hardness, yield strength, percentage elongation, percentage reduction in area after fracture, and impact toughness at temperatures ranging from -40?C to +20?C were evaluated. The results were compared with those of a reference cast steel without these alloying elements, allowing a detailed assessment of the influence of chromium and titanium. The investigation begins with a comprehensive literature review of the effects of these elements in iron-based alloys. The results highlight the influence of chromium and titanium on the mechanical properties and microstructural development of cast steel. These elements play a critical role in enhancing mechanical strength, particularly after quenching and tempering, although there are evident trade-offs in ductility and impact toughness. In addition, the study discusses the damage mechanisms, focusing on the role of titanium nitrides in the cracking process.

The paper investigated the AW7075 aluminum alloy that is used in the automotive industry. The alloy is widely used, among others, in the production of heads and engine blocks. The possibility of obtaining various properties of the alloy (material states) by appropriate heat treatment (saturation and aging) was demonstrated. The results of strength, hardness, abrasion and fracture toughness tests of the alloy in the T73, RRA and HTPP aging treatments, in comparison with the T651 reference state, are presented. The need to select the appropriate parameters of heat treatment in relation to the load conditions of the structural element, especially in elements with notches, was indicated. Depending on the state of the AW7075 alloy, the results prove the wide and diverse possibilities of its use, and should be used consciously in the design and production processes of modern automotive drivetrain components.