20.500.12556/RUL-105863 Mehanske lastnosti in mikrostruktura martenzitnih nerjavnih jekel 08X14NDL in GX4CrNi13-4 Mechanical properties and microstructure of martensitic stainless steels 08X14NDL and GX4CrNi13-4 Namen diplomskega dela je karakterizacija mikrostrukture in mehanskih lastnosti nerjavnih jekel 08X14NDL in GX4CrNi13-4. Karakterizacija mehanskih lastnosti je potekala s pomočjo nateznega preizkusa, merjenja trdote in udarne žilavosti, karakterizacija mikrostrukture pa s pomočjo svetlobne mikroskopije, rentgenske fazne analize (XRD), vrstične elektronske mikroskopije (SEM), energijsko disperzijske spektroskopije (EDS) in izračunov ravnotežnih faznih diagramov za preiskovana jekla. Mikrostruktura jekel 08X14NDL in GX4CrNi13-4 je sestavljena pretežno iz popuščenega martenzita in δ-ferita. Delež δ-ferita se med toplotno obdelavo ne spreminja in znaša 18,7 % za jeklo 08X14NDL in 2,6 % za jeklo GX4CrNi13-4. S pomočjo mikrokemijske analize EDS je bilo ugotovljeno, da δ-ferit v obeh jeklih vsebuje predvsem večji delež kroma in manjši delež niklja kakor martenzit. Mehanske lastnosti jekla GX4CrNi13-4 so dosegale zahteve standarda, pri jeklu 08X14NDL pa so bile trdote prenizke glede na zahteve standarda. Mikrotrdota δ-ferita je bistveno manjša od mikrotrdote martenzita. Z ustrezno kemično sestavo bi v jeklu 08X14NDL lahko zmanjšali delež mehkejšega δ-ferita. The main purpose of the diploma work was characterization of microstructure and mechanical properties of 08X14NDL and GX4CrNi13-4 martensitic stainless steels. Mechanical properties were characterized by tensile testing, hardness testing and impact toughness testing. Microstructure was characterized by using light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and calculation of equilibrium phase diagrams. Microstructure of 08X14NDL and GX4CrNi13-4 steels is composed of martensite and δ-ferrite. The volume fraction of δ-ferrite is 18.7 % for the 08X14NDL steel and 2.6 % for the GX4CrNi13-4 steel and does not change markedly during the process of the heat treatment. EDS microanalysis shows that δ-ferrite in both alloys contains more chromium and less nickel than the martensite. The mechanical properties of the GX4CrNi13-4 steel have met the requirements of the standard while in the case of the 08X14NDL steel the hardness was lower than required. Microhardness of δ-ferrite is significantly lower than the microhardness of martensite. The content of δ-ferrite with lower hardness could be reduced by a proper chemical composition of the 08X14NDL steel. mehanske lastnosti mikrostruktura martenzitna nerjavna jekla 08X14NDL GX4CrNi13-4 &#948 -ferit mechanical properties microstructure martensitic stainless steels 08X14NDL GX4CrNi13-4 &#948 -ferrite true false false Slovenski jezik Angleški jezik Diplomsko delo/naloga 2018-12-21 07:15:05 2018-12-21 07:15:09 2022-08-18 03:46:30 0000-00-00 00:00:00 2018 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 67382 1778527 3194.pdf 3194.pdf 1 C97FE3EDC82DF4A9762E586CD563D7D4 91ebfae495a48fc5fc78ebf41f71665cf948b964cf7077ee92ca5fd50aa6ddf2 3a5016f9-a1b6-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=116554 Naravoslovnotehniška fakulteta 0 0 0