Vrednovanje superčistih čelika prema kemijskom sastavu

Realization of products in power engineering represents the verification and optimization of steel making technology of 2,8NiCrMoV and 3,5NiCrMoV types intended for forgings of the gas turbine shaft and compressor disk. The minimum content of tramp and trace elements is requested, especially phosphorus, sulphur, copper, antimony, arsenic and tin. Silicon, manganese and aluminium are considered as undesirable elements.Realizacija proizvoda u energetskom inženjerstvu predstavlja optimalizaciju tehnologije proizvodnje čelika tipa 2,8NiCrMoV i 3,5NiCrMoV namijenjenim kovanju osovine plinske turbine i diska kompresora. Zahtijeva se minimalni sadržaj pratećih elemenata i oligoelemenata, naročito fosfora, sumpora, bakra, antimona, arsena i kositra. Silicij, magnezij i aluminij se smatraju nepoželjnim elementima

Chemical composition and morphology of oxidic ceramics at filtration of steel deoxidised by aluminium

Composition and morphology of filter ceramics were investigated during filtration of steel deoxidised by aluminium. Filtration was realized with use of filters based on oxidic ceramics Cr2O3, TiO2, SiO2, ZrO2, Al2O3, 3Al2O3•2SiO2 and MgO•Al2O3. It was established that change of interphase (coating) occurs during filtration of steel on the surface of capillaries of ceramics, where content of basic oxidic component decreases. Loss of oxidic component in the coating is replaced by increase of oxides of manganese and iron and it is great extent inversely proportional to the value of Gibbs’ energy of oxide, which forms this initial basis of ceramics

Kemijski sastav i morfologija oksidne keramike tijekom filtriranja aluminijem deoksidiranog čelika

Composition and morphology of filter ceramics were investigated during filtration of steel deoxidised by aluminium. Filtration was realized with use of filters based on oxidic ceramics Cr2O3, TiO2, SiO2, ZrO2, Al2O3, 3Al2O3•2SiO2 and MgO•Al2O3. It was established that change of interphase (coating) occurs during filtration of steel on the surface of capillaries of ceramics, where content of basic oxidic component decreases. Loss of oxidic component in the coating is replaced by increase of oxides of manganese and iron and it is great extent inversely proportional to the value of Gibbs’ energy of oxide, which forms this initial basis of ceramics.Sastav i morfologija filterske keramike ispitivana je tokom filtriranja aluminijem deoksidiranog čelika. Filtriranje je provedeno filterima izrađenim od oksidne keramike Cr2O3, TiO2, SiO2, ZrO2, Al2O3, 3Al2O3•2SiO2 te MgO•Al2O3. Utvrđeno je kako tijekom filtriranja do promjene međufaze (stvaranja sloja) dolazi na kapilarnim površinama keramike, u kojima se udio temeljne oksidne komponente smanjuje. Taj gubitak nadomješten je manganskim i željeznim oksidom i uglavnom je obrnuto proporcionalan vrijednosti Gibbsove energije oksida, koji čini osnovu keramičke tvari