No abstract

á Âèëüíþññêèé òåõíè÷åñêèé óíèâåðñèòåò èì. Ãåäèìèíàñà, Âèëüíþñ, Ëèòâà â Èíñòèòóò òåïëî-è ìàññîîáìåíà èì. À. Â. Ëûêîâà ÍÀÍ Áåëàðóñè, Ìèíñê, Áåëàðóñü Èññëåäóåòñÿ âëèÿíèå îñàaeäåíèÿ â ìàãíèòîðåîëîãè÷åñêîé aeèäêîñòè íà âÿçêîå òðåíèå è êðóòÿùèé ìîìåíò ìàãíèòîðåîëîãè÷åñêîãî òîðìîçà. Ïðîòåñòèðîâàíî ïÿòü ðàçëè÷íûõ ìàãíèòî-ðåîëîãè÷åñêèõ aeèäêîñòåé: MRF-140CG è MRF-122EG (êîðïîðàöèÿ Lord, ÑØÀ), MRHCCS4-A è MRHCCS4-B (êîìïàíèÿ Liquids, Âåëèêîáðèòàíèÿ) è MUDZH-3 (Èí-ò òåïëî-è ìàññîîáìåíà èì. À. Â. Ëûêîâà ÍÀÍ Áåëàðóñè). Âÿçêîñòü ìàãíèòîðåîëîãè÷åñêèõ aeèäêîñòåé â ìàãíèòíîì ïîëå èíòåíñèâíîñòüþ 0-1 Ò èçìåðÿëè ðåîìåòðîì òèïà Anton Paar Physica MCR-301. Äëÿ èñïîëüçîâàíèÿ â ìàãíèòîðåîëîãè÷åñêîì òîðìîçå áûëà âûáðàíà aeèäêîñòü ñ ëó÷øèìè ïàðàìåòðàìè. Ñåäèìåíòàöèþ â ìàãíèòîðåîëîãè÷åñêîé aeèäêîñòè îïðåäåëÿëè çàïàòåíòîâàííûì àâòîðàìè ìåòîäîì, îñíîâàííûì íà èçìåðåíèè ýëåêòðîñîïðîòèâëåíèÿ aeèäêîñòè. Ðàçðàáîòàíà ìàòåìàòè÷åñêàÿ ìîäåëü âÿçêîãî òðåíèÿ è ñåäèìåíòàöèè â çàâèñèìîñòè îò ýëåêòðîñîïðîòèâëåíèÿ aeèäêîñòè. Äëÿ ñìåøèâàíèÿ aeèäêîñòåé âíóòðè ìàãíèòîðåîëîãè÷åñêîãî òîðìîçà èñïîëüçîâàëè ÷åòûðå ïüåçîïðèâîäà. Ñîçäàíà ýêñïåðèìåíòàëüíàÿ óñòàíîâêà äëÿ îïðåäåëåíèÿ êðóòÿùåãî ìîìåíòà òîðìîçà.

Èññëåäîâàíû ïëàñòè÷åñêèå äåôîðìàöèè, âîçíèêàþùèå â ñòàëüíûõ îáðàçöàõ âñëåäñòâèå ìèêðîñòðóêòóðíûõ òðàíñôîðìàöèé ïðè âîçäåéñòâèè âíåøíèõ íàãðóçîê, óðîâåíü êîòîðûõ ìîaeåò íå äîñòèãàòü ïðåäåëà òåêó÷åñòè ìàòåðèàëà. Ðàññìàòðèâàëèñü òðè ëåãèðîâàííûå ñòàëè-THG200 (ïðîèçâîäèòåëü Óääåõîëüì, Øâåöèÿ), 40Õ13 è 95Õ18 (Ðîññèÿ)-ñ ðàçíûìè ëåãèðóþùèìè ýëåìåíòàìè è ïðîöåíòíûì ñîäåðaeàíèåì óãëåðîäà, à òàêaeå ïîâåäåíèåì ïðè ìèêðîñòðóêòóðíûõ òðàíñôîðìàöèÿõ. Ïðè ãåíåðèðîâàíèè èçãèáíûõ íàïðÿaeåíèé ïîðÿäêà 100 ÌÏà, íå ïðåâûøàþùèõ 10% ïðåäåëà òåêó÷åñòè ñòàëåé, íàáëþäàåòñÿ âîçíèêíîâåíèå ïëàñòè÷åñêèõ çîí â ñòàëüíûõ îáðàçöàõ, êîòîðûå ïîäâåðãàëèñü ïðåäâàðèòåëüíîìó íàãðåâó äî 900…1050°Ñ è ïîñëåäóþùåìó èçãèáó ïðè çàêàëêå íà âîçäóõå. Ïëàñòè÷åñêèå äåôîðìàöèè âîçíèêàëè ïðè ðåàëèçàöèè âñåõ ðåaeèìîâ îõëàaeäåíèÿ, êîòîðûå ñîïðîâîaeäàëèñü ìàðòåíñèòíûì ïðåâðàùåíèåì. Ñ ïîìîùüþ ðåíòãåíîãðàôè÷åñêèõ èññëåäîâàíèé áûëî âûÿâëåíî ðàçíîå âëèÿíèå ðàñòÿãèâàþùèõ è ñaeèìàþùèõ èçãèáíûõ íàïðÿaeåíèé íà ìèêðîñòðóêòóðíûå èçìåíåíèÿ ïðè ìàðòåíñèòíûõ ïðåâðàùåíèÿõ.

The main objective of this study was to explore quality increasing and cost reduction opportunities for a production of forged aluminium alloy 6082 connecting rods. These automotive parts are used for air compressors’ of the trucks. Connecting rods undergoes high cyclic loads during exploitation, therefore, the durability of this component is of a critical importance. The main factors characterizing high durability of the connecting rod are hardness and impact strength that may be achieved selecting the proper technology regimes. The main requirements for the aluminium alloy 6082 are hardness in the range of 90–120 HB and impact strength not less than 29.2 J/cm2. Furthermore, the main problem is a stability of testing results of randomly picked connecting rods as these parts are produced in big quantities for the export purposes. Our experiments and recommendations for the development of technology of connecting rods’ allowed maintaining the requirement in hardness, increasing the impact strength approximately twice and reducing the time needed for the production of one connecting rod as it let to save the cost of the part.

Cleaning of contaminated surfaces is closely related to the study of adhesion forces between particles and the surface. Despite numerous technological advancements, the adhesion of particles and surfaces is a phenomenon that is far from being fully understood. This is due to many factors acting during process,-such as the surface roughness and material type, size, shape, electrostatic properties of particles, etc. A surface cleaning device based on nonlinear vibration of the contact element is presented in this paper. Relationships describing the periodic motion in steady state operating regimes are obtained. Characteristics of motion as functions of the frequency of excitation are investigated. Experimental investigations were performed for the determination of the influence of the cleaning velocity on the vibration frequency. It is shown that this dependence is directly related to adhesion forces between particles and the surface. Test results are in good accordance with theoretical predictions.