20.500.12556/RUL-140848 Simulacija termo-mehanskega utrujanja spoja večplastnega litega valja diplomsko delo Thermo-mechanical fatigue simulation of the bond area in a multi-layered cast roll diploma work V diplomski nalogi je obravnavana problematika spoja v večplastnih litih valjih s stališča mehanskega utrujanja med valjanjem. Preizkušali smo odpornost na mehansko utrujanje spojev na valjih z delovno plastjo iz nadevtektoidnega hitroreznega jekla. Centrifugalno liti valji sestavljajo tri plasti: zunanja delovna plast, vmesna plast in jedro. Vmesni spoj, t.i. metalurški spoj, ki nastane s strjevanjem, je ključen za preprečevanje luščenja delovne plasti in s tem tudi za življenjsko dobo valja. Iz preseka delovne plasti skupaj s prehodom v jedro so bili v radialni smeri izdelani vzorci za preizkuse mehanskega utrujanja na termo-mehanskem simulatorju Gleeble 1500. Vzorci so bili pripravljeni tako na mestih z ultrazvočno sprejemljivim spojem kot na mestih, kjer ultrazvočna preiskava predvideva mikrostrukturne napake. Vzorce smo ciklično obremenjevali dokler se niso porušili. Površino testiranih vzorcev smo opazovali pod optičnim in elektronskim mikroskopom. Ocenili smo vzroke za porušitev spojev ter tako primerjali dobre in slabe spoje. Rezultati mehanskega utrujanja lahko služijo za boljše razumevanje nastanka dobrih in slabih spojev v litem valju. The diploma work is addressing the problem of bonding between layers in multi-layered cast rolls with a working layer made of hypereutectoid high sped steel from the standpoint of thermo-mechanical fatigue during rolling. Multilayer cast rolls are made of three layers: the outer working layer, intermediate layer, and core, between which a metallurgical bond is created through solidification. Segments of all three layers (in cross-section) were turned from a multi-layered cast roll for testing on the thermo-mechanical simulator Gleeble 1500. Samples were prepared at places with an ultrasonically acceptable bond as well as at places with limited microstructural errors. Cyclic loading was applied on the samples until they fractured. The fractured surfaces of the tested samples were viewed and evaluated under optical and electron microscope. The results were then compared between the good and the bad bond between layers. The results can serve for better understanding of solidification in the case of good and bad bond formation in cast rolls. dvoplastni valj spoj mehansko utrujanje lom double layer roll bond mechanical fatigue fracture true false false [J. Vodlak] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2022-09-20 09:00:33 2022-09-20 09:00:40 2022-12-12 13:34:09 0000-00-00 00:00:00 2022 0 Ljubljana 0 Ljubljana XIII, 51 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 669 88108 133418499 12730.pdf 12730.pdf 1 B2A097A2D8481A1BA08CBDC7AA4B6C88 8ef36c560ff9bb491df0bf76cbb83272a2c341608595c0ebd3aa19888919220f dd60a767-38b1-11ed-92af-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=161663 Naravoslovnotehniška fakulteta 0 0 0