A novelty in electroenergetics of the recent years are anti-blackout conductors of the HTLS type. These conductors allow for an above average increase of the transmission capacity of electric energy through overhead lines. The high temperature work of such conductor is possible with the use of thermally resistant aluminium alloys with the addition of zirconium. Compared to the traditionally applied material of the EN AW 1370 class, those alloys' permissible work temperature is at the level of 150 to 230 • C (aluminium 80 • C). The production technology for the alloys of this type includes a line of continuous casting and rolling of the wire rod, and next, its long-term heat treatment. The aim of the process of the heating of the wire rod is obtaining the desired level of the material's properties, which will make it possible to obtain the final properties of the wires assigned for the creation of conductors. The paper presents the results of the studies aiming at the description of the influence of the heat treatment of the material obtained in various production process conditions on its mechanical and electric properties.Keywords: aluminium alloys, AlZr, conductive materials, heat treatment, electric conductivity Nowością ostatnich lat w elektroenergetyce są antyblackoutowe przewody typu HTLS. Przewody te umożliwiają ponadprzeciętne zwiększenie zdolności przesyłu energii elektrycznej liniami napowietrznymi. Wysokotemperaturowa praca takiego przewodu, możliwa jest poprzez wykorzystanie odpornych cieplnie stopów aluminium z dodatkiem cyrkonu. Stopy te w porów-naniu z tradycyjnie stosowanym materiałem w gatunku EN AW 1370 posiadają dopuszczalną temperaturę pracy na poziomie 150 do 230 • C (aluminium 80 • C). Technologia produkcji tego typu materiałów obejmuje linię ciągłego odlewania i walcowania walcówki, a następnie jej długoczasową obróbkę cieplną. Celem procesu wygrzewania walcówki jest osiągnięcie wymaganego poziomu własności materiału, który umożliwi uzyskanie końcowych własności drutów, przeznaczonych do budowy przewodów. W pracy przedstawiono wyniki badań zmierzających do określenia wpływu parametrów obróbki cieplnej materiału uzyskanego w rożnych warunkach procesu produkcyjnego na jego własności mechaniczne i elektryczne.
The subject of the present article consists in obtaining the wire production material with the controlled, during the heat treatment, level of electrical and mechanical properties. In the case of the AlZr alloys the appropriate strength properties are obtained in the technological process through the introduction of the specified value of the cold working (work-hardening). In turn,the AlZr alloy resistivity value is dependent on both the amount of the zircon additive and its placement characteristics in the aluminium structure (solid solution or emissions). The paper presents comparative resistivity and hardness tests of the AlZr alloy material with the zircon content ranging from 0.05 to 0.32% mas. Zr produced in the continuous casting technology as well as in the continuous casting and rolling technology.
Endeavours were undertaken to assess metallographically AlMgSi alloys, (containing 0.58 wt% of Mg, and 0.58 wt% or 6.5 wt% of Si) in their primary states as well as after applying external loads in the Static Compression Test. During the first stage of the study the primary microstructures of the investigated samples were assessed. Samples originated from two technological processes: after strain hardening, in a form of rods (φ 9.5 mm and φ 4.0 mm) gravity casting, rolling, homogenisation and precipitation hardening; and after gravity casting in sand moulds of shaped plates 100 mm x 100 mm x 4 mm of a primary structure and after the precipitation hardening. During the second stage of investigations, microstructures of analysed samples (of various technological history) were compared - after applied external loads - in order to obtain information in what way such diversified primary structure and which of its stereological parameters (amount, shape, size and placement) are essential in initiation of microcracks under static loads.
The main scientific challenge of the study was the selection of the zirconium amount, which will allow achieving high electric and strength properties of the alloy. The analysis of chemical compositions of the thermal resistive, conducting AlZr alloys allowed to estimate the most advantageous amount of zirconium, which was found to be within the range: from 0.05 to 0.32 wt % of Zr. The main aim of the study was the investigation of electric properties of alloys of the selected chemical compositions, being within the above given range. The endeavours were focused on determining the heat treatment influence (artificial ageing) on the resistivity of the AlZr alloys in the cast form. On these bases the ranges of obtainable electrical properties were estimated for the investigated alloys, which enabled the selection of optimal conditions of the heat treatment.Keywords: aluminium alloys, heat treament, AlZr, resistivity, Nordheim rule Głównym wyzwaniem naukowym pracy był dobór ilości cyrkonu, która pozwoli uzyskać wysokie własności elektryczne oraz wytrzymałościowe stopu. Analiza składów chemicznych odpornych cieplnie, przewodowych stopów AlZr pozwoliła okreslić najkorzystniejszą ilość dodatku cyrkonu, która mieści się w zakresie od 0,05 do 0,32 % wag. Zr. Zasadniczym celem pracy są badania własności elektrycznych stopów o wybranych składach chemicznych mieszczacych się w powyższym zakresie. W pracy skupiono się na określeniu wpływu obróbki cieplnej (starzenie sztuczne) na zmianę rezystywności stopów AlZr w postaci odlewanej. Na tej podstawie, dla badanych stopów, wyznaczono zakresy możliwych do uzyskania własności elektrycznych, co pozwoliło na dobór optymalnych warunków obróbki cieplnej.
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