Determination of thermal properties of armour steel

V magistrskem delu smo določili toplotne lastnosti ultra visokotrdnega (angl. ultra high hardness, UHH) jekla Swebor Armor 600. Jeklo odlikujeta visoka trdota in trdnost, zato se uporablja za protibalistično zaščito. Prodaja se v gašenem oz. popuščanem stanju predvsem zaradi doseganja trdote, ki mora biti v področju od 590 do 640 HB. V certifikatih o kakovosti materiala Swebor Armor 600 so podane kemijska sestava in mehanske lastnosti, medtem ko podatki o toplotnih lastnostih niso na voljo. V okviru eksperimentalnega dela je bila izvedena analiza toplotnih lastnosti materiala Swebor Armor 600 na napravi Hot Disk TPS 2200, ki deluje po metodi tranzientnega planarnega toplotnega vira (TPS). Meritve so bile izvedene v skladu s standardi skupine ISO 22007. Poleg toplotnih lastnosti smo jeklu izmerili tudi trdoto in analizirali mikrostrukturo. Cilj magistrskega dela je bila natančna določitev toplotnih lastnosti pri različnih temperaturah. Rezultati so pokazali, da se toplotna prevodnost povečuje do temperature 400 °C. Jeklo Swebor Armor 600 lahko uvrstimo med srednje toplotno prevodna jekla s povprečno vrednostjo toplotne prevodnosti pri sobni temperaturi 27,17 W/mK. Meritve trdote so pokazale, da je trdota preiskovanega materiala nekoliko nižja od trdote, ki jo navaja proizvajalec. Mikrostruktura jekla Swebor Armor 600 je martenzitna.The thesis investigates thermal properties of the ultra-high hardness (UHH) steel Swebor Armor 600. Steel is distinguished with high hardness and strength, therefore it is used in ballistic protection. Steel is sold in quenched or tempered state, because achieving planned hardness which has to be between 590 HB and 640 HB. Chemical composition and mechanical properties are given in data sheet for material Swebor Armor 600, while thermal properties are not avalible. Therefore in the experimental part the analysis of thermal properties of the steel Swebor Armor 600 was carried out on the device Hot Disk TPS 2200, which works according to the method of transient plane source method (TPS). Measurements were carried out according to the standards group ISO 22007. In addition to thermal properties we measured hardness and analyzed microstructure of the steel. The aim of the master thesis was to determine thermal properties at different temperatures. The results has shown that thermal conductivity increases up to temperature 400 °C Swebor Armor 600 can be classified as medium thermal conductive steel with an average value of thermal conductivity at room temperature 27,17 W/Km. Hardness measurement have shown, that hardness of inspected material is slightly lower than the hardness indicated by manufacturer. Microstructure of the Swebor Armor 600 is fully martensitic