Hydraulic properties of ladle slags

The article presents results of examining of hydraulic properties of ladle slags formed during production of steel. The studied ladle slags were subjected to different cooling mode from the molten state. Based on the ability of the slag react with the water was assessed their hydraulic activity. The hydraulic properties are caused by the presence of minerals dicalcium silicate, tricalcium aluminate, mayenite, brownmillerite and dicalcium ferite. The emergence of required hydrating phases in the ladle slags is conditioned by a sufficient CaO content and their cooling rate. The contact the slag with water during processing and their ageing has a negative effect. The experiment has shown that the phase transformation of the mineral dicalcium silicate which occurs during cooling of the ladle slags cause their volume instability

Hydraulic properties of ladle slags

The article presents results of examining of hydraulic properties of ladle slags formed during production of steel. The studied ladle slags were subjected to different cooling mode from the molten state. Based on the ability of the slag react with the water was assessed their hydraulic activity. The hydraulic properties are caused by the presence of minerals dicalcium silicate, tricalcium aluminate, mayenite, brownmillerite and dicalcium ferite. The emergence of required hydrating phases in the ladle slags is conditioned by a sufficient CaO content and their cooling rate. The contact the slag with water during processing and their ageing has a negative effect. The experiment has shown that the phase transformation of the mineral dicalcium silicate which occurs during cooling of the ladle slags cause their volume instability

Prijenos topline tijekom hlađenja vrućih površina pomoću vodenih sapnica

Method of cooling in a secondary zone of continuous casting of steel has a significant influence on a quality of continuously cast products mainly from the point of view of internal and surface defects as well as zonal segregations. At the department of thermal engineering, a physical model of the secondary zone has been developed, which enables testing of both water and water-air nozzles. During laboratory measurements cooling effects of a cone nozzle have been expressed by means of three parameters. Most commonly used parameter is an admission characteristic, infrequently heat transfer coefficient is determined and newly a measuring of dynamic impact of the cooling water has been introduced.Tijekom kontinuiranog lijevanja čelika, hlađenje sekundarne zone od značajnog je utjecaja na kvalitetu odljevaka sa aspekta unutrašnjih i površinskih pogrešaka te u kontekstu zonske segregacije u materijalu. U odjelu za termoenergetiku razvijen je fizikalni model sekundarne zone, kojim je omogućeno ispitivanje vodenih sapnica i sapnica za hlađenje mješavinom vode i zraka. Tijekom laboratorijskih mjerenja, efekti hlađenja koničnom sapnicom izraženi su trima parametrima. Nejčešći je pritom parameter admisijske karakteristike, ponekad se određuje i koeficijent prijelaza topline a recentno je uvedeno mjerenje dinamičkog utjecaja rashladne vode

Užsienio kalbos mokomosios medžiagos organizavimas klausimų sistemos pagrindu

In teaching foreign languages, methodical units are linguistic images – sentences, which are modelled according to the purpose of the sentence; the sentence is formed according to the question which it needs to address. In “Teaching map” the whole teaching material focuses on the question (lexicon and grammar) which aids in forming the question and the answer to it. While working with such maps the student is freed from memorizing of certain information (definitions, terms, classification etc.) which he acquires at different times and from different sources (morphology, syntax, lexicology etc.), but which is currently not necessary to this student.Mokant užsienio kalbų, metodiniais vienetais yra kalbiniai vaizdai – sakiniai, modeliuojami pagal sakinio tikslą, kadangi sakinys sukuriamas pagal klausimą, į kurį turi atsakyti. „Mokomajame žemėlapyje“ apie klausimą koncentruojasi visa mokomoji medžiaga (leksika ir gramatika), kurios pagalba formuluojamas klausimas ir atsakymas į jį. Dirbant su tokiais mokomaisiais žemėlapiais, mokinys išlaisvinamas nuo kai kurios informacijos įsiminimo (apibrėžimai, terminai, klasifikacija ir t.t.), kurią jis gauna skirtingu laiku ir skirtingų šaltinių (morfologijos, sintaksės, leksikologijos ir t.t.), bet kuri nėra būtina šiam mokiniui dabartiniu metu

Ispitivanje prijenosa topline u kalupu za kontinuirano lijevanje čelika

This report describes research of thermal processes in primary cooling area in terms of assessment of temperature profiles and determination of thermal flows of the mould. Even formation of casting crust in mould depends on its thermal work, related to distribution of temperature along the height of individual mould walls, which affects operation of the whole continuous casting machine (CCM) in fundamental way. Ideal temperature profile along the height of the mould assures even removal of heat from a blank and it is an essential prerequisite of high quality production. A separate part has been dedicated to ways of preventing breakouts with the use of simulation of kinetics of the mould temperature field. Some of the achieved results are shown on particular examples.Rad prikazuje istraživanje temperaturnih profila i određivanje toplinskih tijekova unutar kalupa u primarnoj zoni hlađenja. Jednolikost stvaranja ljevačke kore u kalupu ovisi o njegovom toplinskom radu, koji je uvjetovan raspodjelom temperature po visini stijenki konkretnog kalupa, što temeljno utječe na aktivnost cijele opreme za kontinuirano lijevanje. Idealan temperaturni profil duž visine stijenke kalupa jamči jednoliko odvođenje topline s površine i nužan je preduvjet kvalitatne proizvodnje. Posebno poglavlje rada obrađuje prevencije površinskog kidanja materijala koristeći kinetičku simulaciju u temperaturnom polju kalupa. Neki rezultati prikazani su na konkretnim primjerima

Heat transfer during cooling of hot surfaces by water nozzles

Method of cooling in a secondary zone of continuous casting of steel has a significant influence on a quality of continuously cast products mainly from the point of view of internal and surface defects as well as zonal segregations. At the department of thermal engineering, a physical model of the secondary zone has been developed, which enables testing of both water and water-air nozzles. During laboratory measurements cooling effects of a cone nozzle have been expressed by means of three parameters. Most commonly used parameter is an admission characteristic, infrequently heat transfer coefficient is determined and newly a measuring of dynamic impact of the cooling water has been introduced

Measurement the Thermal Profile of Steelmaking Ladle with Subsequent Evaluation the Reasons of Lining Damage

Based on the operational measurement, of which content was to determine ladle thermal profile, there were analysed causes of possible damage of lining in steel ladles by steel breakout through the ladle shell. There exists connection between thermal state of ladle lining during the operation and its lifetime. There were reached to the conclusion that the cause of failure in the lining of ladle is except for high temperature of bath, also wide interval of temperature change during the tap operation, in consequence with possible insufficient pre-heating of ladle, discontinuous operation of aggregate and damage of insulating lining layer, respectively deformation of ladles shell

Hydraulic properties of ladle slags

The article presents results of examining of hydraulic properties of ladle slags formed during production of steel. The studied ladle slags were subjected to different cooling mode from the molten state. Based on the ability of the slag react with the water was assessed their hydraulic activity. The hydraulic properties are caused by the presence of minerals dicalcium silicate, tricalcium aluminate, mayenite, brownmillerite and dicalcium ferite. The emergence of required hydrating phases in the ladle slags is conditioned by a sufficient CaO content and their cooling rate. The contact the slag with water during processing and their ageing has a negative effect. The experiment has shown that the phase transformation of the mineral dicalcium silicate which occurs during cooling of the ladle slags cause their volume instability