20.500.12556/DKUM-19826 VPLIV TERMIČNE OBDELAVE NA LOMNO ŽILAVOST VZMETNEGA JEKLA INFLUENCE OF THERMAL TREATMENTS ON FRACTURE TOUGHNESS OF SPRING STEEL Visoko trdnostna jekla se uporabljajo na področjih velikih dinamičnih obremenitev. Zaradi česar se proizvajalci običajno soočajo s težavami, kako zagotoviti trajno dinamično trdnost. Za njeno zagotovitev največkrat posegajo po naknadnih termičnih obdelavah. Namen diplomskega dela je tako narediti primerjalno analizo utrujenostne rasti razpoke v skladu s standardom ASTM E 1820 - 01, za termično mehko in termično obdelano vzmetno jeklo 51CrMOV4. Diplomsko delo temelji na eksperimentalnih meritvah v LSEK laboratoriju na Fakulteti za strojništvo, kjer so se izvajali lomnomehanski preizkusi z metodo mehanike loma, določevale utrujenostne rasti razpoke in materialna parametra Parisovega zakona. Obdelava podatkov je potekala v programu Microsoft Excel 2010, s katerim so tudi bili izrisani diagrami. V diplomskem delu je v splošnem opisana mehanika loma ter področje utrujanja: njeni mehanizmi za nastanek, LCF in HCF utrujanje, določevanje hitrosti rasti razpoke in razni vplivi nastanka. Kratko poglavje v diplomskem delu je namenjeno tudi pripravi upogibnih lomnomehanskih preizkušancev v skladu s standardi. High strength steels are used in fields of large dynamic loads. Leading manufacturers are usually confronted with problems like, how to ensure fatigue limit. To ensure, they mostly reach to subsequent thermal treatment. The purpose of Diploma thesis is, to make a comparative analysis of fatigue crack growth, for thermal soft and thermal treathed 51CrMOV4 spring steel in accordance with ASTM E 1820-01 standard. Diploma work is based on experimental measurements in LSEK laboratory at the Faculty of Engineering, where tests are conducted on fracture toughness with prescriptive method of fracture mechanics, determined fatigue crack growth and material parameters for Paris’ law. Processing of the data was held in Microsoft Excel 2010, with which diagrams also were drawn. The Diploma thesis described in the general field of fracture mechanics and fatigue: the mechanism for the formation, LCF and HCF fatigue, crack growth rate determination and the creation fatigue failure by various effects. A short chapter in the thesis is also intended to prepare the bending fracture toughness specimen in accordance with the standards. Vzmetno jelko 51CrMoV4 mehanika loma LCF in HCF utrujanje lomna žilavost ASTM E1820 - 05 časovno spremenljivo obremenjevanje mikromehanizmi utrujanja širjenje kratkih razpok ASTM E1820 - 01 Wӧhlerjeva krivulja mehanske lastnosti Kitagawa - Takahashijev diagram Parisov zakon utrujenostna rast razpoke Spring steel 51CrMOV4 fracture mechanics LCF and HCF fatigue fracture toughness ASTM E1820 - 05 timely variable loading micromechanisms of fatigue growth of short cracks ASTM E1820 - 01 Wӧhler's curve mechanical properties Kitagawa - Takahashi diagram Paris' law fatigue crack growth true true false [A. Likeb] Slovenski jezik Angleški jezik Diplomsko delo 2011-08-30 15:30:30 2011-09-02 10:27:16 2022-04-13 15:41:27 2023-12-26 03:14:42 2011 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 [539.42:620.178]:669.018.259(043.2) 15806486 URN:SI:UM:DK:7FJ4OY16 UNI_Likeb_Andrej_2011.pdf UNI_Likeb_Andrej_2011.pdf 1 9EE4A687D301785FF62F4D549F6E6FFA d6261f37efb009c579dfc0ae76382ff497a454a239d3f640eeb37adbc2628031 78a20118-7c05-11eb-bb7a-00155d0001ca 20.500.12556/dkum/bde63045-da46-4f49-bb4e-824a6236736c https://dk.um.si/Dokument.php?lang=slv&id=24210 Fakulteta za strojništvo 0 0 0