Legnica University of Management

Abstract The machinability of two copper alloys with lead: CuZn40Pb2 and CuSn5Zn5Pb2, was assessed. Turning tests were performed based on the selection of parameters that will result in the tool being worn out after 1 minute. Tool wear was assessed by observing dimensional and microstructural changes in the blade. When assessing machinability, power consumption, chip shape, changes in the surface layer and surface roughness were taken into account. The research aims to determine the custom machinability index of materials used in SANHA Polska. A publicly available index must be adapted to a given application, and such adaptation is often quite time-consuming. Therefore, a 1-minute test was carried out as a quick and cheap alternative to a large fleet of machines with various machining properties. The developed methodology and the results obtained are the basis for further research conducted as part of the implementation doctorate, the aim of which is to implement the production of well-machinable lead-free materials for drinking water installations, characterized by good solderability and corrosion resistance. As a result of the conducted research, the role of lead in the machining of copper alloys was identified, which is important due to European restrictions on the elimination of this element and its replacement in a way that allows for precise removal processing.

This work concerns two stages of research into plasma nitriding (change of nitriding steel and modification of nitriding parameters). In the first stage, pins obtained from currently used steel were compared with pins made of an alternative material available on the market, using the same nitriding process parameters. As a result of the metallographic tests carried out, in the first case, the presence of a thin, porous, and heterogeneous nitrided layer or its absence was found, with the core in its raw state and not thermally improved. In the second case, the presence of a nitrided layer of small thickness with noticeable porosity on the surface of the sample was found, but with a core after heat treatment (incorrect process parameters). Therefore, modification of the parameters of the nitriding process was proposed, in terms of a mixture of gases, currents, time, and temperature of the nitriding process. As a result, a satisfactory effective thickness of the nitrided layer was obtained, consisting of a white near-surface zone with ε and ε + γ′-type nitrides with a thickness of 8.7 to 10.2 µm, and a dark zone of internal nitriding with γ′ nitrides. The nitrides layer was continuous, compact, and well adhered to the steel surface. In the core of the samples, the presence of a fine-needle tempering sorbite structure with a small amount of fine bainite, which is correct for the steel after heat treatment and nitriding, was found. The most favorable parameters of the ion nitriding process were gas flow rate (1.5 L/min N; 0.4 L/min H; 0.3 L/min Ar); currents (BIAS—410 V 4.0 A, SCREEN—320 V 4.0 A); time (26 h and 35 min); and temperature (550 °C).

The article reveals the essence of the concept of “responsible person” and the problem of its пenesis. Different theoretical and methodological approaches to its definition are shown. The phenomenon of social responsibility is considered as the basis of productive social creativity. The author analyzes the main trends and the nature of the process of formation of social responsibility of the individual in modern conditions. Particular attention is paid to increasing the role of personal responsibility in times of social instability and uncertainty. The accumulated experience of scientific understanding of the concept of «social responsibility» is revealed. Specific features of social responsibility and its interpretation in the works of F.Bastia, I. A. Ilyin, P. A. Kropotkin, I. I. Lapshin, N. O. Lossky, V. S. Solovyov, N. F. Fedorov, and others.