27 KB414 KB25 KB200020242009Kljajin, MilanMarušić, SanjaMarušić, Vlatkoštevilka:2letnik:43str. 103-108ISSN:1580-2949COBISSID:725674URN:URN:NBN:SI:doc-8QPU015OenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijemikrostrukturaobrabastiskalnicezvariAn investigation of the economics of using welded layers for some parts of worm presses for the extraction of oil from sunflower seeds| Raziskave uporabnosti navarjenih plasti za dele vijačnih stiskalnic za ekstrakcijo olja sončnic|The working parts of worm presses from different manufacturers were collected from oil mills in Croatia, Vojvodina and Bosnia and Herzegovina. The chemical composition, microstructure and hardness were determined, and the wear was examined for the original (imported) and the substituted (domestic) parts. The direct costs of tribological origin are larger for the substitute parts than for the original parts and they depend on the protective surface layer. The indirect tribological losses are a few tens of times greater than the direct tribological losses. The wear resistance of the welded layers was tested experimentally on extraction cage knives and the results are compared to carburised knives (the substitution solution) commonly used in oil mills. It was found that the wear resistance of the welded layers does not depend only on the surface hardness, but more so on the microhardness and the distribution of the carbide particles in the tough matrix. Based on recordings in oil mills and on the results of our investigation, we concluded that the use of welded layers instead of carburised layers could extend the life cycle of the parts of the presses. In this way, the efficiency of the oil extraction could be increased and the economics of operating oil mills could be improvedZbrani so bili deli različnih proizvajalcev za stiskalnice za sončnično olje iz oljarn na Hrvaškem, v Vojvodini in v Bosni in Hercegovini. Analizirana je bila kemična sestava, izmerjena trdota, pregledana mikrostruktura in analizirana obraba izvirnih (uvoženih) in nadomestnih (domačih) delov. Neposredni stroški tribološkega izvora so za nadomestne dele večji kot za izvirne in so odvisni od površinske (varovalne) plasti. Indirektni tribološki stroški so nekaj desetkrat večji od direktnih. Obrabno obstojnost navarjenih slojev smo eksperimentalno preverili na nožih iz ekstrakcijske kletke, rezultate pa smo primerjali s cementiranimi noži (nadomestna rešitev), ki se večinoma uporabljajo v oljarnah. Ugotovili smo, da obrabna obstojnost navarjenih plasti ni odvisna samo od trdote površine, ampak bolj od mikrotrdote in od porazdelitve karbidnih zrn v žilavi matici. Na podlagi podatkov iz oljarn in rezultatov raziskave sklepamo, da lahko uporaba navarjenih plasti namesto cementiranih podaljša trajnostno dobo delov stiskalnic. Tako se poveča učinkovitost ekstrakcije olja in izboljša gospodarnost oljarnTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije