Papers by Author: Piotr Osuch

Abstract: Among multiple applications 6XXX-series aluminum alloys are widely used as electrical conductor for overhead power lines. For that application Al-Mg-Si alloys are produced mainly in the form of wire rod in the continuous casting and rolling lines (CCR). There is many technological routes possible to transform the Al-Mg-Si wire-rod into precipitation hardened, ready to use Al-Mg-Si wires. One of these routes involves using the heat of continuous casting and rolling process to artificial ageing of wire-rod, which is motivated by ecological premise. In the current paper the results of continuous heat treatment of the wire-rod within the CCR line (involving quenching of the alloy to artificial ageing temperature) on the microstructure and properties has been examined. It was shown the structure of wire rod formed in such process is very irregular. TEM investigations has shown that many heterogeneous particles are present and the arrangement of the β main hardening phase is very inhomogeneous with wide precipitate free zones occurred. However this type of microstructure has a positive effect on electrical properties of the material in question, which is important taking into consideration application of the alloy.

Abstract: The Al-Mg-Si alloys, due to their unique combination of lightweight, mechanical and electrical properties and excellent corrosion resistance, are used as a material for the production of overhead power conductors, commonly known as AAAC (All Aluminium Alloy Conductor). Wires intended for conductor manufacturing are obtained from the wire rod produced by a continuous casting and rolling line (CCR, e.g., Continuus-Properzi). The Al-Mg-Si wire rod can be processed into ready-made wires by different technological routes, which mainly consist of different combinations of strain hardening as well as precipitation hardening of wire rod or wires. In Europe the conventional technological route comprises solution heat treatment of wire rod coils (heated at temperatures over ~500 °C, followed by quenching into water), then natural ageing of wire rod at ambient temperature for a couple of days, next wire drawing, and finally artificial ageing.This paper discusses results of investigations on developing an alternative technological route. In this process heat from the continuous casting and rolling process by Continuus-Properzi is used for heat treatment of the wire rod. The new technological route allows the abandonment of the high temperature heat treatment as well as natural ageing of the wire rod, making the production process less energy consuming, cheaper and faster than the conventional one. The current paper presents research results identifying the structure of materials from different Al-Mg-Si wires production process routes. It also focuses on electrical and mechanical properties.

Abstract: Precipitation hardening AlMgSi alloys are widely used not only as constructional material, but also a very attractive material for the manufacturing of conductors for overhead power lines. These alloys, with a mass density typical of aluminum and with relatively low resistivity, reach twice the level of mechanical properties, compared to aluminum. Semi-finished product in the manufacturing of overhead conductors is wire rod produced by the technology of the continuous casting and rolling (CCR), for example Continuus-Properzi. The entire complex of wire rod required properties (electrical, tensile, rheological, fatigue) are obtained through proper selection of the quantities of alloying elements (Si, Mg) and structure modifier (Fe, Ti) as well as the right combination of type and sequence of thermo-mechanical treatments and technological process parameters. The article discusses the physical background of opportunities to controlling the wire rod properties, taking into consideration all elements of technology for continuous casting and rolling and also thermo-mechanical treatments. In particular, article contains the presentation and analysis of investigations results identifying the structure, electrical properties and hardness of materials from particular stages of the process, refer to physical phenomena affecting the properties of the material during CCR process including the final product intended for the manufacture of wires.

Abstract: The paper focuses on 6xxx series AlMgSi conductor alloys. Such alloys are used for manufacturing of conductors for power transmission. Since the most current standards define as many as seven types of wires with various mechanical and electrical specifications, the existing philosophy of AlMgSi wires manufacturing technology for electrical applications has to be revised. Strength specifications of precipitation hardened AlMgSi alloys may be enhanced by strain and by precipitation hardening. Therefore from the scientific point of view identification seems to be relevant of the impact of the sequence of these mechanisms on development of final wire properties. In particular, this paper tries to answer the following question: Does the sequence of hardening mechanisms affect the development of mechanical properties of AlMgSi alloy wires The paper presents results of a study of the impact of artificial ageing parameters of 6201 grade AlMgSi alloy wires on their final properties. The study results are presented and discussed in two parts. The first part addresses the impact of artificial aging temperature and duration on the strength properties of AlMgSi (grade 6201) alloy wire rod. The second part is focused on hardening development in the process of drawing of a AlMgSi wire made of the same alloy grade, subjected to different thermal treatments, the parameters of which have been selected based on analysis of the results of the first, wire-rod related, part of the study.