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The influence of chemical composition of nanofluids on dimensional changes of hardened constructional steel

Gęstwa W.

Journal of Achievements in Materials and Manufacturing Engineering

2017

Vol. 85, nr 1

5--11

Purpose: The possibility definition of utilization of the quenching from the nanofluids group is to the hardened of elements created from constructional steels. The definition of influence size of nanofluids on the dimension changes of the element created from low carbon constructional steel is also the important aspect of this work. Design/methodology/approach: Methodology used during investigations enclosed two areas. First area enclosed the investigation of quenching mediums propriety in the support about the English method, which permitted estimate of their warmth receipt ability in the support about cooling curved in the arrangement the temperature – the time or the cooling speed. Second area enclosed the investigations of the hardened element which let define dimension changes and hardness on the transverse section. The formed structure was also estimated on the cross section in the support about the light microscope. Findings: of this article is show the possibility obtainment of minimum dimension changes the element of the cooled in nanofluids near the retained of hardness and structure on the level which was got in the quenching mediums until now used for the studied material. The summery up the use of quenching mediums of the nanofluids group at the base of distilled water, ammoniac water and Al2O3 nanoparticles causes decrease of dimension changes near keep on the same of hardness of hardened elements from constructional steel. Research limitations/implications: Research limitations result from the quantity of the quenching mediums used in the investigations which one can use as the point of the reference for nanofluids. This arose from initial investigations over this aspect, which is the dimension change of elements. It should also use real the parts of machines or tool in farther investigations. Practical implications: of results presented in this article, we will get in the range of the construction projecting of steel elements, where should consider technological surpluses for this element and material proprieties which has to which meet. For full utilization in the practice, however you should conduct additional investigations still both in the laboratory scale, how and industrial. Originality/value: Originality of this article is the performance of the influence of quenching mediums from the group nanofluids on the dimension changes of hardened steel elements.

Napełnione kompozycje epoksydowe utwardzane produktem degradacji chemicznej poli(tereftalanu etylenu)

Fabrycy E., Spychaj T., Pilawka R., Michalski J.

Kompozyty

2002

R. 2, nr 4

149-152

Badano kompozycje i kompozyty- epoksydowe utwardzane produktem aminoglikolizy poli(tereftalanu etylenu) (PET/TEA). Jako żywic użyto Aralditu F oraz Epidianu 6, jako napelniaczy: wodzianu glinu, krzemionki, mieszaniny talku i kaolinu w stosunku wagowym 1:1 oraz ziemi krzemionkowej. Do kompozytów wprowadzano 50 lub 65 części napełniacza na 100 części wagowych żywicy epoksydowej. Utwardzacz PET/TEA stosowano w dwóch udziałach wagowych 19,2 lub 16,5 g na 100 g żywicy, co odpowiada założeniu, że 1 atom azotu w utwardzaczu przypada na 6 lub 7 grup epoksydowych żywicy. Badano przebieg procesu sieciowania oraz właściwości mechaniczne i elektryczne utwardzonych kompozytów. W celu wybrania kompozytów o najlepszych właściwościach elektrycznych prowadzono badania zmiany właściwości w warunkach wilgotnego gorąca stałego: temperatury 40°C i wilgotności względnej 95%. W badaniach długotrwałych najmniejsze zmiany właściwości wykazały kompozyty z krzemionką oraz mieszaniną talku i kaolinu.

Epoxy compositions and resulting composites based on Araldit F and Epidian 6 resins (Table 1) and inorganic fillers (silica, aluminum hydroxide and mixture of talc and kaolin (1:1 wt./wt.)) hardened with poly(ethylene terephthala-te)/triethanoloamine (PET/TEA) chemical degradation product have been prepared and characterized. Mineral fillers have been applied in amounts of 50 or 65 g per 100 g of epoxy resin. Two ratios of the PET/TEA hardener have been applied 16.5 or 19.2 g per 100 g of epoxy resin (equivalent to 7 or 6 epoxy groups of the resin per 1 nitrogen atom of the hardener, respectively). It has been found that life times of the filled epoxy compositions based on Epidian 6 resin (at 80°C) are similar to these of unfilled system with exception of that containing talk + kaolin mixture. In the last case life time is substantially prelonged (from 45 to 80 min). Mechanical properties (tensile, flexural and impact strengths) of the filled epoxy composites are decreased as compared with unfilled (Tables 2-4) whereas glass temperatures are almost unchanged (Tables 2 and 3). The composites show good electrical properties (dielectric constant, dielectric loss coefficient tg<5, volume resistivity, electric arc resistance and break down resistance) (Table 5) which are partially deteriorated .after long time tests at elevated temperature (40°C) and humidity (95%) (Table 6). The lowest changes of electrical properties have been found for epoxy composites filled with silica and talc + kaolin mixture. The composites are considered as insulating materials for on-air insulators of low and medium voltage.