13 KB51 KB11 KB199219991998Arzenšek, BorisKmetič, DimitrijKosec, BorutSkobir, Danijelaštevilka:3/4letnik:32str. 173-175ISSN:1318-0010COBISSID:50602URN:URN:NBN:SI:doc-TH86TAW7slInštitut za kovinske materiale in tehnologijeŽelezarna JeseniceŽelezarna RavneŽelezarna ŠtoreKovine zlitine tehnologijedeformacijejeklomatematični modelimehanske lastnostitrdnostOpis krivulj tečenja jekel z različnimi matematičnimi modeli| The description of true stress - true strain curves by different mathematical models|Steel deformation abilities are described by true stress - true strain (stress-strain) curves. Their exact knowledge is of a great importance at development of steel deformations technologies and construction of remaking devices. The stress - strain curves are established by tension, compression or torsion tests, mainly as possible by similar test like at projected deformation process. The course of stress - strain curves are often pictured by experimental results of by mathematical terms. The mathematical term, by which we wish to describe the deformation abilities of the steel, as exactly as possible, is chosen to get the minimum difference between experimental and functional results. In the paper the true stress - true strain curves for four different steels are represented. The curves were described by exponential and polynomial functions. In the work the differences between functional results and real deformations stresses were presented also. The deformation abilities of the choosen steels were made by compression tests. It is represented that not correct choosen function has a great influence on realistic presentation of the steel deformation abilities, specially at lower and higher deformation degreesNatančno poznanje preoblikovalnih sposobnosti jekel, ki jih prikazujemo s krivuljami tečenja, je pri razvijanju tehnologij preoblikovanja velikega pomena. Najpogosteje jih ugotavljamo s preizkusom, ki je po načinu preoblikovanja čim bolj podoben načrtovanemu preoblikovalnemu procesu. Krivulje tečenja velikokrat opisujemo z eksperimentalno ugotovljenimi vrednostmi preoblikovalnih trdnosti, ali pa z različnimi matematičnimi izrazi. V delu smo prikazali krivulje tečenja za štiri vrste jekel, ki se po preoblikovalnosti precej razlikujejo. Podali smo jih v obliki eksponentne funkcije in polinoma druge stopnje ter naredili primerjavo med funkcijskimi in dejanskimi vrednostmi preoblikovalnih trdnosti. Namen dela je bil ugotoviti, s katerim matematičnim izrazom lahko preoblikovalne trdnosti opišemo tako, da so razlike med dejanskimi in funkcijskimi vrednostmi najmanjšeNadaljuje se kot: Materiali in tehnologijeTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije