{"?xml":{"@version":"1.0"},"edm:RDF":{"@xmlns:dc":"http://purl.org/dc/elements/1.1/","@xmlns:edm":"http://www.europeana.eu/schemas/edm/","@xmlns:wgs84_pos":"http://www.w3.org/2003/01/geo/wgs84_pos","@xmlns:foaf":"http://xmlns.com/foaf/0.1/","@xmlns:rdaGr2":"http://rdvocab.info/ElementsGr2","@xmlns:oai":"http://www.openarchives.org/OAI/2.0/","@xmlns:owl":"http://www.w3.org/2002/07/owl#","@xmlns:rdf":"http://www.w3.org/1999/02/22-rdf-syntax-ns#","@xmlns:ore":"http://www.openarchives.org/ore/terms/","@xmlns:skos":"http://www.w3.org/2004/02/skos/core#","@xmlns:dcterms":"http://purl.org/dc/terms/","edm:WebResource":[{"@rdf:about":"http://www.dlib.si/stream/URN:NBN:SI:DOC-YEUU1TDR/8f89f05e-116d-4d06-9dd0-f25cc7d297e4/HTML","dcterms:extent":"33 KB"},{"@rdf:about":"http://www.dlib.si/stream/URN:NBN:SI:DOC-YEUU1TDR/bbde22d0-94cb-4350-977a-782d207269b7/PDF","dcterms:extent":"467 KB"},{"@rdf:about":"http://www.dlib.si/stream/URN:NBN:SI:DOC-YEUU1TDR/549a54ca-5fd2-4a6a-99ec-2dc336720ab2/TEXT","dcterms:extent":"30 KB"}],"edm:TimeSpan":{"@rdf:about":"2000-2024","edm:begin":{"@xml:lang":"en","#text":"2000"},"edm:end":{"@xml:lang":"en","#text":"2024"}},"edm:ProvidedCHO":{"@rdf:about":"URN:NBN:SI:DOC-YEUU1TDR","dcterms:isPartOf":[{"@rdf:resource":"https://www.dlib.si/details/urn:nbn:si:spr-ihg6vo21"},{"@xml:lang":"sl","#text":"Materiali in tehnologije"}],"dcterms:issued":"2011","dc:creator":["Leskovšek, Vojteh","Senčič, Bojan"],"dc:format":[{"@xml:lang":"sl","#text":"številka:1"},{"@xml:lang":"sl","#text":"letnik:45"},{"@xml:lang":"sl","#text":"str. 67-73"}],"dc:identifier":["ISSN:1580-2949","COBISSID:851370","URN:URN:NBN:SI:doc-YEUU1TDR"],"dc:language":"en","dc:publisher":{"@xml:lang":"sl","#text":"Inštitut za kovinske materiale in tehnologije"},"dc:subject":[{"@xml:lang":"sl","#text":"lomna žilavost"},{"@xml:lang":"sl","#text":"mikrostruktura"},{"@xml:lang":"sl","#text":"trdota"},{"@xml:lang":"sl","#text":"vakuumska toplotna obdelava"},{"@xml:lang":"sl","#text":"vzmetno jeklo"},{"@rdf:resource":"http://www.wikidata.org/entity/Q3236003"}],"dcterms:temporal":{"@rdf:resource":"2000-2024"},"dc:title":{"@xml:lang":"sl","#text":"Fracture toughness of the vacuum-heat-treated spring steel 51CrV4| Lomna žilavost vakuumsko toplotno obdelanega vzmetnega jekla 51CrV4|"},"dc:description":[{"@xml:lang":"sl","#text":"In the work the possibilities of the vacuum heat treatment of spring steel grade 51CrV4 are presented. Charpy-V notch (CVN) impact-test values are widely used in toughness specifications for spring steels, even though the fracturing energy is not directly related to the spring design. The plain-strain stress-intensity factor (KIc) at the on set of unstable crack growth can be related to the spring design; however, KIc values are not used in the toughness specifications. This is surprising since to the designer KIc values are more useful than CVN values, because the design calculations for springs from high-strength steels should also take into account the strength and the toughness of materials to prevent rapid and brittle fracture. An investigation was conducted to determine whether standardized fracture-toughness testing (ASTM E399-90), which is difficult to perform reliably for hard and low ductility materials, could be replaced with a non-standard testing method using circumferentially notched and fatigue-precracked tensile specimens. The results of this investigation have shown that using the proposed method it was possible to draw, for the normally used range of working hardness, combined tempering diagrams (Rockwell-C hardness - Fracture toughness KIc - Tempering temperature) for the vacuum-heat-treated spring steel grade 51CrV4. Fractographic and metallographic analyses of the KIc-test specimens used shows in steel the presence of positive and negative segregations. It was found that the width of the segregations bands and the distance between the positive and negative segregations influence significantly the fracture toughness due to the presence of bainite in the negative segregations"},{"@xml:lang":"sl","#text":"V članku so predstavljene možnosti vakuumske toplotne obdelave vzmetnega jekla 51CrV4. Vrednosti Charpy-V udarne žilavost (CVN) so pogosto navedene v specifikacijah za vzmetna jekla, čeprav energija loma ni neposredno povezana z dimenzioniranjem vzmeti. Ravninsko deformacijski faktor intenzitete napetosti (KIc) na začetku nestabilne razpoke lahko uporabimo pri dimenzioniranju vzmeti, vendar pa vrednosti KIc ne najdemo v specifikacijah. To je presenetljivo, saj so za konstruktorje vrednosti KIc bolj uporabne od vrednosti CVN za visokotrdnostne vzmeti, pri katerih je treba upoštevati poleg trdnosti tudi žilavost materiala, da preprečimo lom. Opravljena je bila preiskava, s katero smo želeli ugotoviti, ali lahko standardizirano preizkušanje lomne žilavosti (ASTM E399-90), ki je težko izvedljivo za trde in krhke materiale z majhno duktilnostjo, nadomestimo z nestandardnim postopkom preizkušanja lomne žilavosti s cilindričnim nateznim preizkušancem z zarezo po obodu in utrujenostjo razpoko v dnu zareze. Rezultati raziskave so pokazali, da s predlagano metodo lahko konstruiramo diagram popuščanja (trdota Rockwell-C - lomna žilavost KIc - temperatura popuščanja) za vakuumsko toplotno obdelano vzmetno jeklo 51CrV4. S fraktografsko in metalografsko analizo KIc preizkusnih vzorcev smo ugotovili prisotnost pozitivnih in negativnih izcej v jeklu. Ugotovljeno je bilo, da širina izcej in razdalja med njimi pomembno vplivata na lomno žilavost, in sicer zaradi prisotnosti bainita v negativnih izcejah"}],"edm:type":"TEXT","dc:type":[{"@xml:lang":"sl","#text":"znanstveno časopisje"},{"@xml:lang":"en","#text":"journals"},{"@rdf:resource":"http://www.wikidata.org/entity/Q361785"}]},"ore:Aggregation":{"@rdf:about":"http://www.dlib.si/?URN=URN:NBN:SI:DOC-YEUU1TDR","edm:aggregatedCHO":{"@rdf:resource":"URN:NBN:SI:DOC-YEUU1TDR"},"edm:isShownBy":{"@rdf:resource":"http://www.dlib.si/stream/URN:NBN:SI:DOC-YEUU1TDR/bbde22d0-94cb-4350-977a-782d207269b7/PDF"},"edm:rights":{"@rdf:resource":"http://rightsstatements.org/vocab/InC/1.0/"},"edm:provider":"Slovenian National E-content Aggregator","edm:intermediateProvider":{"@xml:lang":"en","#text":"National and University Library of Slovenia"},"edm:dataProvider":{"@xml:lang":"sl","#text":"Inštitut za kovinske materiale in tehnologije"},"edm:object":{"@rdf:resource":"http://www.dlib.si/streamdb/URN:NBN:SI:DOC-YEUU1TDR/maxi/edm"},"edm:isShownAt":{"@rdf:resource":"http://www.dlib.si/details/URN:NBN:SI:DOC-YEUU1TDR"}}}}