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Nerjavno izločevalno utrjeno jeklo 17-4 PH je znano po svojih odličnih mehanskih lastnostih in zelo dobri odpornosti proti koroziji. Uporabnost jekla je široka in sega v mnoga področja, kot so letalska industrija, kemijska industrija, prehrambena industrija, izdelavo papirja in splošno jeklarsko industrijo. V okviru diplomskega dela smo izvedli meritve toplotnih lastnosti s pomočjo naprave Hot Disk TPS 2200 na osnovi metode tranzientnega planarnega toplotnega vira v skladu s standardom ISO 22007-2. Naprava Hot Disk TPS 2200 je visokokakovostna in sodobna naprava za določanje toplotnih lastnosti najrazličnejših materialov. V delu so opisane tudi lastnosti jekla 17-4 PH in njegove toplotne obdelave. Predstavljene so tudi sorodne metode za merjenje in določevanje toplotnih lastnosti materialov. Izvedene so bile meritve oziroma določitve toplotnih lastnosti jekla v tako imenovanem dobavljenem stanju in po dveh standardnih toplotnih obdelavah. Srednje izmerjene vrednosti toplotnih lastnosti vseh treh analiziranih vzorcev jekla 17-4 PH pri sobni temperaturi znašajo: v tako imenovanem dobavljenem stanju (toplotna prevodnost 13,04 W/(m K), specifična toplota 3,457 MJ/(m3 K), ter temperaturna prevodnost 3,776 mm2/s), po izvedeni toplotni obdelavi H 900 (toplotna prevodnost 14,6 W/(m K), specifična toplota 3,314 MJ/(m3 K), ter temperaturna prevodnost 4,412 mm2/s) in po izvedeni toplotni obdelavi H 925 (toplotna prevodnost 15,47 W/(m K), specifična toplota 3,651 MJ/(m3 K), ter temperaturna prevodnost 4,242 mm2/s). Ugotovili smo, da ima najvišjo toplotno prevodnost vzorec jekla 17-4 PH po toplotni obdelavi H 925. Precipitation hardening 17-4 PH stainless steel is known for its excellent mechanical properties and high corrosion resistance. The applicability of steel is wide ranging to many areas such as aerospace, chemical, food industry, paper production and general steel industry. As part of the thesis, we performed measurements of thermal properties using the Hot Disk TPS 2200 device based on the transient planar heat source method in accordance with the ISO 22007-2 standard. The Hot Disk TPS 2200 device is a high-quality and modern device used for determining the thermal properties of a wide variety of materials. The work also describes the properties of steel 17-4 PH and its heat treatment. Related methods for measuring and determining the thermal properties of materials are also presented. Measurements and determinations of the thermal properties of the steel were performed in the so-called delivered state and after two standard heat treatments. The average measured values of the thermal properties of all three analysed samples of 17-4 PH steel at room temperature are: in the so-called delivered state (thermal conductivity 13,04 W/(m K), specific heat 3,457 MJ/(m3 K), and temperature diffusivity 3,776 mm2/s), after heat treatment H 900 (thermal conductivity 14,60 W/(m K), specific heat 3,314 MJ/(m3 K), and temperature diffusivity 4,412 mm2/s) and after heat treatment H 925 (thermal conductivity 15,47 W/(m K), specific heat 3,651 MJ/(m3 K), and temperature diffusivity 4,242 mm2/s). We conclude that the 17-4 PH steel sample has the highest thermal conductivity after H 925 heat treatment. |
