diplomsko delo
Grega Čebulj (Author), Milan Bizjak (Mentor), Gorazd Kosec (Co-mentor)

Abstract

Diplomsko delo zajema določitev optimalne temperature toplotne obdelave jekla PROTAC 500M. Poudarek je na vplivu toplotne obdelave na mehanske lastnosti oziroma na ustrezno kombinacijo le-teh. Obravnavana problematika zajema predvsem meritve trdote. Temperaturo faznih transformacij Ac1 in Ac3 smo določili s pomočjo kalilne vrste, dilatometrije in izračuna z uporabo znanih empiričnih enačb. Za določitev optimalnega intervala kalilnih temperatur smo vzorce jekla kalili iz različnih temperatur nad točko Ac3 v vodi. Kaljeno jeklo smo nizkotemperaturno popuščali takoj po kaljenju. Kaljeni vzorci imajo martenzitno mikrostrukturo. V martenzitni osnovi so prisotna mesta z drobnimi karbidi. Mesta predstavljajo samopopuščni martenzit. Z naraščajočo temperaturo popuščanja se izločki karbidov večajo. Rezultati metalografske analize in mehanskih preizkusov kažejo, da smo s kaljenjem iz temperature 850 °C in popuščanjem pri 200 °C dosegli najustreznejšo kombinacijo mehanskih lastnosti.

Keywords

jeklo PROTAC 500M;kemična sestava;temperature faznih transformacij;mikrostrukturna analiza;trdota;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL NTF - Faculty of Natural Sciences and Engineering
Publisher: [G. Čebulj]
UDC: 669
COBISS: 1723999 Link will open in a new window
Views: 1024
Downloads: 552
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Other data

Secondary language: English
Secondary title: heat treatment optimisation of armour steel
Secondary abstract: The diploma thesis includes determining the optimal temperature for the heat treatment of the PROTAC 500M steel. The emphasis was on the influence of heat treatment on mechanical properties as well as on the appropriate combination of these. The problems discussed include mainly the measurements of hardness. The temperature of the phase transformations Ac1 and Ac3 was determined by means of the quench type and dilatometry, and calculated using known empirical equations. In order to determine the optimal interval of the quenching temperatures, the steel samples were emitted from different temperatures above the point Ac3 in water. We low temperature tempered the tempered steel immediately after hardening. Tempered samples have a martensitic microstructure. In the martensitic basis, small carbides are present. Areas represent self-tempering martensit. With the rising tempering temperature, carbide excretion increases. The results of the metallographic analysis and mechanical tests show that the hardening of 850°C and tempering at 200°C achieved the most appropriate combination of mechanical properties.
Secondary keywords: PROTAC 500M steel;chemical composition;temperature phase transformations;microstructure analysis;hardness;
Type (COBISS): Final paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Naravoslovnotehniška fak. , Odd. za materiale in metalurgijo
Pages: 52 f.
ID: 10915124