Papers by Author: Tadeusz Knych

Abstract: The subject of the work focuses on hardened-precipitation type alloys Al-Mg-Si which constitute the primary component material used to build homogeneous electric wires, type AAAC (All Aluminium Alloy Conductor). The material in consideration is a well-known and well-studied alloy, particularly in terms of the possibilities for using it in thermal treatment processes. However, the subject literature does not present a comprehensive recognition of the effect of heat treatment parameters on the set of mechanical and electrical properties in wires grade 6101. In particular, the study presents the results of experiments that show the possibility of controlling the AlMgSi wire properties by means of selecting the heat treatment parameters for simultaneously obtaining a high tensile strength and high electrical conductivity. Hence, the research described in this paper focuses mostly on determining the impact of the Mg and Si content on the electrical and mechanical properties of wires of Al-Mg-Si wire alloys.

Abstract: All over the world, intensive research is being conducted on the development of new conductive materials to be used in power engineering. The objective of this research is to increase electrical conductivity in wire and cable materials, and consequently, to increase line current-carrying capacities and reduce losses in electric energy transfer. Today, the expectations in the power engineering sector concentrates on conductive materials with electrical conductivity higher than conductivity of base materials, i.e. aluminum. The scientific discovery of the recent years, graphene, one of carbon allotropic variants with a very high electrical and thermal conductivity and mechanical strength, creates great possibilities to design and manufacture new materials, with super-standard functional properties. Graphene, can be a new kind of “alloy additive” to aluminum, which can significantly change their electric and another properties.This article focuses attention on the possibilities of graphene and aluminum synthesis. The researches was made over the different methods of producing these materials, in particular: chemical synthesis consisting in the combination of liquid metal with graphene into a form suitable for further processing in the processes of forming into wires. The article presents the results of mechanical properties and structural studies of aluminum-graphene composites.

Abstract: The paper presents the results of studies on obtaining the alloy and generating a set of very high mechanical and electrical properties of wires. The paper also presents the results of testing the rheological resistance in the form of stress relaxation tests carried out on the wires after various thermomechanical treatment processes. The optimum parameters of the thermo-mechanical treatment of the alloy were determined, enabling obtaining the most favorable mechanical and electrical properties of wires. The relationships of the influence of the material and its deformation on the changes in the mechanical and electrical properties of wires were determined. In addition, a microstructural analysis was carried out of casts and wires using scanning electron microscopy. Cast material was subject to observation and the material at successive stages of heat treatment.

Abstract: Integrated continuous casting processes are an important element of the production process in modern industry. Requirements for quality and exploitation properties of products obtained using continuous casting processes necessitate a revision of the role of impurities distribution in the material. This paper concerns on the influence of the casting process on the distribution of alloy additions. Spectroscopy studies were performed for the most sensitive elements, from the segregation, (i.e. : iron and silicon) point of view. Next obtained research results were correlated with the parameters of chemical composition such as casting speed, the presence of a modifier and the processing of metal crystallization zone. Analysis of the results clearly shows the presence of iron and silicon normal macrosegregation. It was observed that the concentration of these elements is highest in the casting axis and, in the case of iron, is 50% higher in the axis than in the circumference of casts.

Abstract: The paper presents research on the effects of magnesium content on electrical and mechanical properties of materials after heat treatment of the casting of aluminum alloys: AlSi5Mg0.3, AlSi5Mg0.8 and AlSi5Mg1. The proposed heat treatment consisted of homogenisation at 535°C during period of the time 8 h, quenched to water and artificial aging at temperatures ranging from 120 to 240°C during period of the time to 24 h. Determination of strength properties were realized by Brinell hardness measurements. Electrical properties are in the form of electrical conductivity. The research program also included analysis of the microstructure of selected alloys.

Abstract: Modern power industry expects new, dedicated aluminum based alloys with non-standard properties, including increased resistance to temperature. Materials exhibiting higher thermal resistance allow to increase operating temperature of electrical conductors, which results in the increase of their current carrying capacity. Commonly known and used in such applications are alloys from the AlZr group. Despite their advantages scientists from around the world are searching for new alternatives. In this paper authors present research results on Al-Mo and Al-Ag alloys with particular interest to the analysis of the molybdenum addition to the aluminum in the amount of 0.05, 0.1, 0.2% and silver addition in the amount of 0.05, 0.1, 0.15% by mass on the mechanical and electrical properties of obtained alloys. Tests were also carried out for reference material which is high-purity aluminum and the AlZr alloy, both in the as cast state temper. Results showed a significant change of temperature coefficient of resistance in Al-Ag alloys compared to Al, which leads to possible increase of the Joule’a heat without the raise of conductors temperature limit. On the other hand, above-average heat resistance of alloys from the Al-Mo group of materials was achieved during the trials. On that basis authors state that Al-Ag alloys may be used for the production of ACSS conductors and Al-Mo alloys for TACSR or TACIR type of conductors.This study was performed under a project financed by NCBiR within the INNOTECH II program.

Abstract: Traditional carrying equipment that is being still used in polish railway system for dozens of years is based on typical steel profiles with low mechanical strength, low corrosion resistance and also with poor assembly and adjustment possibilities. Major part of other overhead railway equipment like support constructions, trolley wires and current carrying equipment is now modernized leaving the carrying system one of the lasts that needs to be redesigned and optimized to meet nowadays requirements for high speeds of railway travel. For that direct reason a project was started to conduct research works on design and development of the new type of railway overhead carrying equipment with enhanced exploitation properties. Within this articles authors presented a complete set of research results including designing of first concepts, FEM simulation and experimental research results including tests on final geometries in actual railway traffic. Performed studies and design works allowed to obtain an innovative overhead railway carrying system which is based on 6082 aluminum alloy and new geometry of used profiles and connection system. Research results conducted and presented within article are a part of the project co-founded by The National Centre for Research and Development.

Abstract: Due to specific application of the Zn-Cu-Ti alloy rolled sheets as a roofing material, ready-made sheets has to meet some specific requirements of bendability at relatively low temperatures, as low as 5°C. In the current paper it was shown that susceptibility of the Zn-Cu-Ti sheets to low temperature bending, is closely related to degree of its dynamic recrystallization during rolling process. The paper discusses effect of different technological routes on the microstructure, mechanical properties and in particular the low temperature performance of Zn-Cu-Ti rolled sheets. The experimental results shows that the homogenization of Zn-Cu-Ti casted strips at the pre-rolling stage can play important role in recrystallization of the sheets during rolling. The current work is part of research on designing new technological route.

Abstract: The paper raises the issue of antimicrobial copper and its alloys constituting a promising solution for the constantly increasing problem of dangerous hospital-acquired infections. The major aim of the presented work is a precise analysis of antimicrobial copper alloys approved by The Environmental Protection Agency (EPA) in accordance with the Unified Numbering System, taking into account their European and international equivalent symbols as well – CEN and ISO, respectively. The analysis focuses mostly on the copper alloy types which the EPA list is composed of, their prices as well as materials and technological properties.

Abstract: The paper present results of the research on the laboratory drawing process of zinc obtained in industrial conditions in the CCR by Properzi method. The force drawing, mechanical properties before and after process was measured and formability limit in drawing process was specified. Because the wire drawing process was on hot (above the recrystallization temperature) the material didn’t work hardening as a function of strain which reduces the ductility and breaking just after the die. The microscopic images of microstructure reveal the presence of large twins recrystallization reflecting the dynamic renewal structure.