903 KB24 KB200020242014Anđić, ZoranFilipović, MirjanaKamberović, ŽeljkoKorać, Marijaštevilka:3letnik:48str. 343-348COBISSID:1055402ISSN:1580-2949URN:URN:NBN:SI:doc-GVEFCRILenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijebelo lito železofracture toughnesslomna žilavostniobijev karbidniobium carbideobrabawear resistencewhite cast ironželezove zlitineWear resistance and dynamic fracture toughness of hypoeutectic high-chromium white cast iron alloyed with niobium and vanadium| Odpornost proti obrabi in dinamična lomna žilavost podevtektičnega belega litega železa, legiranega z niobijem in vanadijem|The influence of mass fractions 1.5 % Nb and 1.5 % V, added singly and in combination, on the microstructural characteristics and properties relevant to the service performance of the hypoeutectic high-chromium white iron containing 18 % Cr and 2.9 % C, namely, the wear resistance and the fracture toughness, has been examined. The Fe-Cr-C-Nb-V alloy gives the best compromise between the wear resistance and the fracture toughness. The dynamic fracture toughness of this alloy is larger by about 42 % and the abrasion wear resistance is larger by about 33 % than the properties of the basic Fe-Cr-C alloy. The presence of NbC carbides in the structure, caused by adding niobium to the alloy, contributes to an improvement of the wear resistance and the dynamic fracture toughness. On the other hand, the higher fracture toughness was attributed to the strengthening during fracture, since very fine secondary carbide particles were present, mainly in the austenitic matrix (as a result of the vanadium addition). The secondary carbides that precipitate in the matrix regions also influence the abrasion behaviour. By increasing the matrix strength through a dispersion-hardening effect, the fine secondary carbides can increase the mechanical support of M7C3 eutectic carbidesPreučevan je bil vpliv dodatka masnega deleža Nb 1,5 % in V 1,5 %, posamezno in v kombinaciji, na značilnosti mikrostrukture in uporabne lastnosti podevtektičnega kromovega belega železa z 18 % Cr in 2,9 % C ter na obrabno odpornost in lomno žilavost. Zlitina Fe-Cr-C-Nb-V je najboljši kompromis med odpornostjo proti obrabi in lomno žilavostjo. V primerjavi z osnovno Fe-Cr-C-zlitino ima ta zlitina okrog 42 % večjo dinamično lomno žilavost in okrog 33 % večjo odpornost proti abraziji. Prisotnost NbC-karbidov zaradi dodatka niobija zlitini prispeva k izboljšanju odpornosti proti obrabi in povečanju dinamične lomne žilavosti. Po drugi plati se višjo lomno žilavost pripisuje utrjevanju med širjenjem preloma, ker so zelo drobni delci sekundarnih karbidov pretežno v avstenitni osnovi (kot posledica dodatka vanadija). Sekundarni karbidi, ki se izločajo v osnovi, tudi vplivajo na vedenje pri obrabi. S povečanjem trdnosti osnove zaradi učinka disperzijskega utrjevanja drobni sekundarni karbidi lahko povečajo mehansko podporo evtektičnih karbidov M7C3TEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije