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1

Effect of Non-Metallic Inclusions on the Hot Ductility of High-Mn Steels

Opiela Marek, Fojt-Dymara Gabriela

Advances in Science and Technology. Research Journal

|

2023

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Vol. 17, no 3

19--30

EN

The aim of the work was to determine the effect of non-metallic inclusions on the hot ductility of two newly developed high-Mn austenitic steels (27Mn-4Si-2Al and 24Mn-3Si-1.5Al-Ti). For this purpose, a hot tensile test was carried out in the temperature range from 1050°C to 1200°C with a constant strain rate of 2.5⸱10-3 s-1. The tests were performed on the Gleeble 3800 thermomechanical simulator. Hot ductility of tested steels was defined by determining the reduction in area (% RA). Examined steels demonstrate diversified hot ductility. Clearly higher hot ductility was noted for the 24Mn-3Si-1.5Al-Ti steel. The reduction in area of this steel in the temperature range from 1050°C to 1200°C decreases from approx. 90% to about 58%, while the reduction in area of the 27Mn-4Si-2Al steel, in the same temperature range, decreases from approx. 66% to about 34%. The presence of single, regular-shaped AlN particles and complex MnS-AlN-type non-metallic inclusions was revealed in the 27Mn-4Si-2Al steel. Whereas fine (Ce, La, Nd)S-type sulphides, properly modified with rare earth elements, were identified in the 24Mn-3Si-1.5Al-Ti steel. The AlN-type inclusions and complex MnS-AlN-type inclusions were not revealed in the 24Mn-3Si-1.5Al-Ti steel. This is due to the presence of Ti microaddition, the concentration of which guaranteed binding of the whole nitrogen into stable TiN-type nitrides. Sulphides, disclosed in the 24Mn-3Si-1.5Al-Ti steel, are globular or slightly elongated in the direction of plastic deformation, as confirmed by a very low value of the elongation factor equal 1.48. This creates the opportunity to produce sheets of high strength and ductility and low anisotropy of mechanical properties.

2

Stale konstrukcyjne typu maraging wytapiane próżniowo – zależność ciągliwości od zawartości wtrąceń niemetalicznych

Pawlak Stanisław Jerzy

Stal, Metale & Nowe Technologie

|

2022

|

nr 3-4

30--36

PL

W pracy analizowano ilościową zależność pomiędzy ciągliwością a zawartością wtrąceń niemetalicznych w odkuwkach o dużym przekroju z wytapianej próżniowo stali wysokostopowej typu maraging X2NiCoMo18-9-5. Wykonano badania własności wytrzymałościowych odkuwek i czystości metalurgicznej stali pochodzących z 17 wytopów przemysłowych. Obróbkę cieplną prowadzono według dwóch technologii różniących się sposobem austenityzowania, przy czym warunki starzenia były takie same, co prowadziło do uzyskania zbliżonych wartości wytrzymałości stali. Natomiast własności plastyczne stali przy ustalonej technologii produkcji były znacznie zróżnicowane, a główną przyczyną tego była czystość metalurgiczna stali.

EN

In the paper, the quantitative relationship between the ductility and volume fraction of the non-metallic inclusions in the vacuum melted X2NiCoMo18-9-5 maraging steel has been analysed. The tensile properties and cleanliness of steels from 17 industrial melts in the form of forged bars were determined. Two variants of the heat treatment in the austenitic range were used, followed by the same ageing conditions, which lead to the similar strength values of the steels. In contrary to that, significant variability in the tensile ductility was observed, which was attributed to the cleanliness of the steels.

3

Investigation of Particle Filtration in Aluminium Alloy

Baumann Benedict, Keßler A., Hoppach E., Wolf G., Szucki M., Hilger O.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

70--80

EN

The objective of this work is to gain a deeper understanding of the separation effects and particle movement during filtration of non-metallic inclusions in aluminum casting on a macroscopic level. To understand particle movement, complex simulations are performed using Flow 3D. One focus is the influence of the filter position in the casting system with regard to filtration efficiency. For this purpose, a real filter geometry is scanned with computed tomography (CT) and integrated into the simulation as an STL file. This allows the filtration processes of particles to be represented as realistically as possible. The models provide a look inside the casting system and the flow conditions before, in, and after the filter, which cannot be mapped in real casting tests. In the second part of this work, the casting models used in the simulation are replicated and cast in real casting trials. In order to gain further knowledge about filtration and particle movement, non-metallic particles are added to the melt and then separated by a filter. These particles are then detected in the filter by metallographic analysis. The numerical simulations of particle movement in an aluminum melt during filtration, give predictions in reasonable agreement with experimental measurements.

4

Influence of inclusions on bending fatigue strength coefficient the medium carbon steel melted in an electric furnace

Lipiński Tomasz, Wach Anna

Production Engineering Archives

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2020

|

Vol. 26, Iss. 3

88--91

EN

The parameters of high-grade steel are influenced by a combination of factors, including chemical composition and production technology. The impurity content is also a key determinant of the quality of high-grade steel. Inclusions may also play an important role, subject to their type and shape. Inclusions may increase the strength of steel by inhibiting the development of micro-cracks. The analyzed material was one grade of medium-carbon structural steel. The study was performed on 6 heats produced in an industrial plant in 140 ton electric furnaces. The experimental variants were compared in view of the five heat treatment options. The results were presented to account for the correlations between the fatigue strength coefficient during rotary bending, the diameter of and spacing between impurities. The relationship between the fatigue strength and hardness of highgrade steel vs. the quotient of the diameter of impurities and the spacing between impurities was determined. The proposed equations contribute to the existing knowledge base of practices impact of impurities with various diameters and spacing between non-metallic inclusion on fatigue strength.

5

Diagnostyka pracy kadzi pośrednich stosowanych do odlewania wlewków płaskich i kwadratowych

Suchan Hanna, Baran Klaudia, Cwudziński Adam

Hutnik, Wiadomości Hutnicze

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2020

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Vol. 87, nr 1-2

17--21

PL

W artykule przedstawiono wpływ pracy kadzi pośredniej na jakość odlewanych w sposób ciągły stalowych wlewków płaskich i kwadratowych. Przeprowadzenie badań na modelu wodnym pozwoliło uzyskać krzywe RTD typu F, na podstawie których określono strefę przejściową tworzącą się podczas odlewania sekwencyjnego dwóch różnych gatunków stali. Efektem wykonania symulacji numerycznych w programie Ansys-Fluent było określenie rozmieszczenia wtrąceń niemetalicznych w ciekłej stali oraz ocena poziomu rafinacji stali w trakcie procesu ciągłego odlewania.

EN

The article presents influence of tundish work on slabs and blooms quality during continuous steel casting. Water model investigations gave Residence Time Distributions curves type F, which allowed to define the transition zone between two different grades of steel during the sequential casting process. The Ansys-Fluent computer program was used for numerical simulation of non-metallic inclusions behaviour in the liquid steel and for estimation of inclusions removal level from liquid steel during casting.

6

Badania filtracji ciekłej stali przez wielootworowe filtry ceramiczne w zależności od powierzchni kontaktu ciekła stal-filtr

Bogdał Agnieszka, Walaszczyk Klaudia, Felis Piotr, Superniak Adrian, Warzecha Marek

Hutnik, Wiadomości Hutnicze

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2020

|

Vol. 87, nr 9

221--224

PL

W pracy przedstawiono wyniki badań filtracji ciekłej stali przez wielootworowe filtry ceramiczne. Przedmiotem badań była stal wysokowęglowa z gatunku C70D. Proces przeprowadzono z zastosowaniem filtrów o różnej wysokości, a zarazem o różnej powierzchni filtracji, w układach filtru pojedynczego oraz podwójnego i potrójnego. Przeprowadzone badania miały na celu zbadanie procesu filtracji stali poprzez wyznaczenie ilości wtrąceń niemetalicznych i ich udziałów powierzchniowych przed i po procesie filtracji. Kolejnym etapem badań było określenie skuteczności filtracji względem ilości wtrąceń niemetalicznych i udziałów powierzchniowych.

EN

The paper presents the results of research on filtration process of high-carbon steel (grade C70D) through multi-hole ceramic filters. The process was carried out using filters with different highs - single filter, double and triple filter system. The research was aimed at determining the amount of nonmetallic inclusions and their surface shares before and after the filtration process. The next stage of the study was to determine the filtration efficiency relative to the amount of non-metallic inclusions and surface shares.

7

Influence of multi-hole filter modification on the flow hydrodynamic structure and refining process of liquid steel in the one-strand tundish

Bartosiewicz M., Cwudziński A.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

71--78

EN

In this work, the authors proposed a modification of the working space one-strand tundish adapted for slab casting process. Numerical simulations of liquid steel flow in the considered flow reactor were performed. The tundish is equipped with a dam with a multi-hole filter. Two variants of the filter hole arrangement were tested and their effect on the liquid steel flow hydrodynamic structure in the tundish was examined. The computer calculations results were verified by performing experiments on the water model. The result of numerical and physical simulations an RTD (Residence Time Distribution) type F curve was generated, which define the transition zone between the cast steel grades during the sequential casting process. The results of the researches showed that the modification of a dam with a multi-hole filter affects on the formation of the liquid steel flow hydrodynamic structure and the transition zone. Furthermore, examinations of the liquid steel refining ability in the considered tundish were carried out. The influence of the filter holes arrangement on the non-metallic inclusions flotation process to the slag phase and liquid steel filtration processes was checked. Numerical simulations were performed in the Ansys-Fluent computer program.

8

The Effect of CaSiAl Modification on the Non-metallic Inclusions and Mechanical Properties of Low-carbon Microalloyed Cast Steel

Kalandyk B., Zapała R., Sobula S., Tęcza G.

Archives of Foundry Engineering

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2019

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iss. 1

47--52

EN

The effect of CaSiAl modification (43-49% Ca, 43-48% Si, 2% Al) on the non-metallic inclusions and mechanical properties of cast low-carbon steel is discussed. Tests were carried out on the cast steel with 0.2% C and micro-additives of V and Nb, used mainly for heavy steel castings (e.g. slag ladles). The modifier in an amount of 1.5 and 3 kg / Mg was introduced to the liquid steel before tapping the metal into a ladle. Test ingots of Y type and a weight of 10 kg were cast and then subjected to a normalizing heat treatment. Using light microscopy and scanning electron microscopy, qualitative and quantitative evaluation of the non-metallic inclusions present in as-cast samples was carried out. Additionally, tests of mechanical strength and impact strength were performed on cast steel with and without the different content of modifier. It was found that increasing the modifier addition affected impact strength but had no significant effect on tensile strength and yield strength. The material with high impact strength had the smallest area fraction of non-metallic inclusions in the microstructure (0.20%). The introduction of modifiers changed the morphology of non-metallic inclusions from dendritic to regular and nodular shapes.

9

Bending fatigue strength coefficient the low carbon steel with impurities

Lipiński T.

Production Engineering Archives

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2018

|

Vol. 21

20--23

EN

The article discusses the results of a study investigating the effect of the number of fine non-metallic inclusions (up to 2 μm in size) on the fatigue strength of structural steel during rotary bending. The study was performed on 7 heats produced in an industrial plant. Fourteen heats were produced in a 100 ton oxygen converter. All heats were subjected to vacuum circulation degassing. Steel sections with a diameter of 18 mm were hardened and tempered at a temperature of 200, 300, 400, 500 and 600°C. The experimental variants were compared in view of the applied melting technology and heat treatment options. The heat treatments were selected to produce heats with different microstructure of steel, from hard microstructure of tempered martensite, through sorbitol to the ductile microstructure of spheroidite. The results were presented graphically, and the fatigue strength of steel with a varied share of non-metallic inclusions was determined during rotary bending. The results revealed that fatigue strength is determined by the relative volume of fine non-metallic inclusions and tempering temperature.

10

Problem of damage to curved switch rails in ordinary turnouts

Czarnecki M., Bińkowski R.

Problemy Kolejnictwa

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2018

|

Z. 180

79--86

EN

The article presents the problem of excessive wear of curved switch rails in ordinary railway turnouts, which is characterized by spallings and the decrement of material on a certain length of the switch rail near the tip. The problem is important, as such wear arises in turnouts on railway lines after several months of exploitation following modernization. The probable reasons behind the excessive wear of switch rails in railway turnouts are indicated on the basis of laboratory tests performed in accordance with PN-EN 13674-1:2011 and PN-EN 13674-2+A1:2010, as well as on the basis of simulations and analyses carried out by the fi nite element method (FEM).

11

Laboratory studies on the development of composite pellets for deep refining of steel from non-metallic inclusions

Szypuła I., Zdonek B.

Prace Instytutu Metalurgii Żelaza

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2018

|

T. 70, nr 3

25--31

EN

The paper presents the laboratory research on the development of a new type of refining materials in the form of composite pellets for deep refining of steel from non-metallic inclusions, measured by the total oxygen content in steel below 10 ppm and the average size of non-metallic inclusions below 3 μm. The study included the development of a technology for pelletising materials selected for composite pellets, development of a technology for drying and hardening of pellets, making a batch of pellets and a series of laboratory heats using the produced pellets, assessment of the usefulness of composite pellets for industrial research, and development of assumptions for these tests.

PL

Przedstawiono badania laboratoryjne nad opracowaniem nowego rodzaju rafinacyjnych materiałów w postaci kompozytowych grudek do głębokiej rafinacji stali z wtrąceń niemetalicznych, mierzonej zawartością tlenu całkowitego w stali poniżej 10 ppm i średnią wielkością wtrąceń niemetalicznych, poniżej 3 µm. Opracowano technologię grudkowania materiałów dobranych na kompozytowe grudki, opracowano technologię suszenia i utwardzenia grudek, wykonano partię grudek oraz serię laboratoryjnych wytopów z wykorzystaniem wytworzonych grudek, dokonano oceny przydatności grudek kompozytowych do badań przemysłowych oraz opracowano założenia do tych badań.

12

Wpływ wylewu osłonowego kadzi stalowniczej i zmiany jego położenia na proces flotacji wtrąceń niemetalicznych z ciekłej stali w sześcio-wylewowej kadzi pośredniej

Bartosiewicz M., Cwudziński A.

Hutnik, Wiadomości Hutnicze

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2018

|

Vol. 85, nr 5

161--166

PL

W artykule przedstawiono wyniki symulacji numerycznych przepływu ciekłej stali w sześcio-wylewowej kadzi pośredniej przeznaczonej do ciągłego odlewania wlewków kwadratowych. Zbadano wpływ zastosowania i zmiany głębokości zanurzenia w ciekłej stali wylewu osłonowego kadzi stalowniczej. Autorzy zaproponowali trzy warianty głębokości zanurzenia wylewu osłonowego. Bazowym wariantem badawczym była kadź pośrednia zasilana z kadzi stalowniczej niewyposażonej w wylew osłonowy. W ramach badań wykonano analizę struktury hydrodynamicznej przepływu ciekłej stali w strefie oddziaływania strumienia zasilającego. Ponadto, sprawdzono zdolność rafinacyjną wtrąceń niemetalicznych badanej kadzi pośredniej i wykonano analizę dystrybucji wtrąceń niemetalicznych pomiędzy poszczególnymi krystalizatorami. Wyniki obliczeń wykazały, iż zastosowanie i zmiana położenia wylewu osłonowego kadzi stalowniczej w procesie ciągłego odlewania stali wpływa na kierunki przepływu ciekłej stali w strefie oddziaływania strumienia zasilającego i na proces flotacji wtrąceń niemetalicznych do fazy żużla.

EN

The paper presents outcomes of the liquid steel flow numerical simulation in the six-strand tundish for continuous billet casting. Influence of use and change the ladle shroud immersion depth in liquid steel was examined. The authors proposed three cases of the ladle shroud immersion depths. The base research variant was tundish which was feeded by steel ladle without ladle shroud. The analysis of the liquid steel flow hydrodynamic structure was performed in the zone of main supplying stream influencing for all of the considered variants. Furthermore, ability of non-metallic inclusions refining in the considered tundish was checked and the analysis of the non-metallic inclusions distribution between the individual molds was performed. The calculation results showed that the use and location change of the ladle shroud in the continuous steel casting process affected the direction of liquid steel flow in the zone of the influence of main supplying stream and on the process of non-metallic inclusions floatation into slag.

13

Ocena wpływu warunków odlewania stalowego wlewka ciągłego na zachowanie się wtrąceń niemetalicznych – modelowanie numeryczne

Bielnicki M., Jowsa J.

Hutnik, Wiadomości Hutnicze

|

2018

|

Vol. 85, nr 11

377--381

PL

W pracy przedstawiono wyniki symulacji numerycznych zachowania się wtrąceń niemetalicznych w krystalizatorze. Analizowano wpływ: geometrii wylewu zanurzeniowego, prędkości odlewania, gęstości wtrąceń niemetalicznych oraz średnicy wtrąceń niemetalicznych na udział procentowy wtrąceń zasymilowanych przez żużel krystalizatorowy. Obliczenia wykonano w programie AnsysFluent®. Zaprezentowano przykładowe trajektorie ruchu wtrąceń niemetalicznych.Na podstawie wyników symulacji stwierdzono, że geometria wylewu zanurzeniowego wywiera najistotniejszy wpływ na liczbę wtrąceń niemetalicznych zasymilowanych przez żużel.

EN

In this paper the results of numerical simulations of behavior of non-metallic inclusion in mold are presented. The impact of: submerged entry nozzle geometry, casting speed, density of non-metallic inclusions and diameter of non-metallic inclusions on the percentage of inclusions assimilated by mold slag was analyzed. The calculations was carried out in Ansys Fluent® program. The examples of non-metallic inclusions trajectories are presented. Based on simulation results it was concluded, that submerged entry nozzle geometry exerts a most important influence on the number of non-metallic inclusions assimilated by the slag.

14

The Effect of the Diameter and Spacing Between Impurities on the Fatigue Strength Coefficient of Structural Steel

Lipiński T.

Archives of Metallurgy and Materials

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2018

|

Vol. 63, iss. 1

519--524

EN

The article discusses the effect of the diameter and spacing between impurities (size up to 2 μm) on the fatigue strength coefficient of structural steel during rotary bending. The study was performed on 21 heats produced in an industrial plant. Fourteen heats were produced in 140 ton electric furnaces, and 7 heats were performed in a 100 ton oxygen converter. All heats were desulfurized. Seven heats from electrical furnaces were refined with argon, and heats from the converter were subjected to vacuum circulation degassing. Steel sections with a diameter of 18 mm were hardened for 30 minutes from the austenitizing temperature of 880°C and tempered at a temperature of 200, 300, 400, 500 and 600°C. The experimental variants were compared in view of the applied melting technology and heat treatment options. The results were presented graphically and mathematically to account for the correlations between the fatigue strength coefficient during rotary bending, the diameter of and spacing between submicroscopic impurities. Equations for calculating the fatigue strength coefficient at each tempering temperature and a general equation for all tempering temperatures were proposed. Equations for estimating the fatigue strength coefficient based on the relative volume of submicroscopic non-metallic inclusions were also presented. The relationship between the fatigue strength and hardness of highgrade steel vs. the quotient of the diameter of impurities and the spacing between impurities, and the fatigue strength and hardness of steel vs. the relative volume of submicroscopic non-metallic impurities were determined.

15

The Effect of Non-Metallic Inclusions Formed as a Result of Deoxidation on the Fatigue Strength of 15CrNi6 and 16MnCr5 Steel

Lipa S., Sawicki J., Dybowski K., Pietrasik R., Januszewicz B.

Archives of Metallurgy and Materials

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2018

|

Vol. 63, iss. 3

1345--1350

EN

This paper presents the findings of fatigue strength tests of 15CrNi6 steel following low-pressure carburizing and oil quenching, subjected to cycles of one-sided three-point bending. The fatigue fractures were compared with the results of fatigue strength studies of 16MnCr5 steel following low-pressure carburizing and nitrogen quenching. The fatigue tests for 16MnCr5 steel were conducted as part of a high-cycle resonance test, with a pendular bending load. The study also involved an analysis of the effects on non-metallic inclusions in the structure on the mechanism of fatigue destruction. The inclusions were found to initiate fatigue cracks. In both cases, a similar method of a fatigue fissure initiation was observed, independent of the study method or specimen material.

16

Ocena powtarzalności czystości metalurgicznej łuków ortodontycznych

Koczkodon K., Grygier D.

Aktualne Problemy Biomechaniki

|

2018

|

z. 15

13--20

PL

Materiały metaliczne przeznaczone do produkcji aparatów ortodontycznych powinny posiadać następujące cechy: wysokie właściwości mechaniczne i fizykochemiczne, biokompatybilność i jednorodność struktury. Bardzo ważnym aspektem jest również ich stopień zanieczyszczenia wtrąceniami niemetalicznymi. Wyniki badań prezentowanych w pracy wykazały dużą różnorodność w zakresie czystości metalurgicznej materiału badanych drutów, mogącej wskazywać, iż w analizowanej partii łuków znajdują się produkty pochodzące z różnych wytopów, znacząco różniące się jakością wykonania.

EN

The metallic materials designed to production of braces possess following features: high mechanical and physicochemical proprieties, biocompatibility and homogeneity of structure. Very important point is also degree non-metallic inclusion. The results of investigations presented in work show the large diverseness of metallurgical cleanness of studied wires material, which lead that various product could coming from different melting, non-uniform with quality of realization.

17

Numerical analysis of the effect of nonmetallic inclusionslocation in carburized layer of 16MNCR5 steel on initiation of fatigue cracking

Lipa Sebastian

Advances in Science and Technology. Research Journal

|

2018

|

Vol. 12, no 3

66--74

EN

This paper presents the results of a numerical analysis of the effect of the position of non-metallic inclusions in a hardened top layer in 16MnCr5 steel on the mechanism of fatigue destruction. An analysis of a hardened layer formed by thermo-chemical treatment using FineCarb® technology was conducted.Non-metallic inclusions formed by deoxidation of steel were studied; they are usually made of calcium and aluminum. Four positions of inclusions in the hardened layer were tested: under the layer, in the middle part of the layer, under the surface and on the border of two sublayers. The results of the FEM analysis were treated as a qualitative analysis. A map of plastic strains around the inclusion under study was observed. The appearance of plastic strains in the area under analysis signaledthe initiation of a fatigue crack. It was observed that the mechanism of destruction depends largely on the distribution of stress in the top layer and on the place where the inclusion is anchored in the layer. Inclusions under the layer were found to be the main cause of the loss of the structural continuity, which explains the most frequent cases of the initiation of fatigue cracks.

18

Wpływ energii mieszania na zjawisko aglomeracji cząstek wtrąceń niemetalicznych w ciekłej stali

Kuglin K., Kalisz D.

Prace Instytutu Odlewnictwa

|

2017

|

Vol. 57, no. 1

11--18

PL

W pracy wykonano obliczenia komputerowe, które polegały na rozwiązaniu równania bilansu populacji oraz równania częstotliwości zderzeń cząstek wtrąceń niemetalicznych w zależności od typu kolizji. W symulacjach wykorzystano metodę PSG (Particle Grouping Method). Badania zostały przeprowadzone dla określonej liczby cząstek tlenku glinu. Za wartości zmienne przyjęto promień cząstki oraz moc mieszania ε. Wyniki symulacji zaprezentowano w formie wykresów przedstawiających zmianę ilości wydzieleń w stosunku do ich liczby początkowej (n1/N0) dla pierwszej grupy rozmiarowej (n1) w funkcji czasu rzeczywistego, dla każdej rozpatrywanej początkowej wielkości promienia cząstki: 1, 5 i 10 μm. Analiza opracowanych wyników pozwoliła stwierdzić, że w przypadku cząstek charakteryzujących się większym promieniem wzrost energii mieszania intensyfikuje proces łączenia się wtrąceń niemetalicznych w aglomeraty, co w konsekwencji sprzyja procesom ich usuwania z objętości ciekłego metalu.

EN

In the research, computer calculations were performed, consisting in solving the equation of population balance and the equation of the collision frequency of non-metallic inclusion particles, depending on the type of collision. In the simulations, the PSG method (Particle Grouping Method) was applied. The studies were conducted for a specific number of aluminium oxide particles. The particle radius and the power of mixing ε were assumed as variables. The simulation results were presented in the form of diagrams showing the change of the number of precipitates in respect of their initial number (n1/N0) for the first group of sizes (n1) in real-time, for each analyzed initial size of the particle radius: 1, 5 and 10 μm. The analysis of the elaborated results made it possible to conclude that, in the case of particles characterized by a larger radius, the increased energy mix intensifies the process of inclusions joining in agglomerates, which, in consequence, favours the processes of their removal from the volume of the liquid metal.

19

Deoxidation Impact on Non-Metallic Inclusions and Characterization Methods

Nicolini C.

Journal of Casting & Materials Engineering

|

2017

|

Vol. 1, no. 4

97--102

EN

Deoxidation is an unavoidable step in the elaboration of steel. The study of its influence could improve the quality of low-carbon steel (0.20–0.25 wt.% of carbon). There are many deoxidation methods, and the most-common one consists of adding aluminum. Although it is a classic method, determining the optimal process parameters (quantity, yield, etc.) could be very sensitive. Deoxidation plays a determining role on inclusion cleanliness, especially on sulfide morphology. In order to control the efficiency of deoxidation, different techniques can be used. In this paper, an automated counting procedure on a scanning electron microscope with a field emission gun (FEG-SEM) is presented. This method was applied on samples cast in our laboratory under different deoxidation conditions. According to this, the resulting inclusion population is correlated with the aluminum content to find the optimal process parameters.

20

Calculation of Assimilation Process of Non-metallic Inclusions by Slag

Kalisz D.

Journal of Casting & Materials Engineering

|

2017

|

Vol. 1, no. 2

43--47

EN

This paper presents the results of calculating the phenomenon of the absorption of non-metallic precipitates in steel by slag. Calculations are made for the forces acting on the non-metallic particles in steel during the flow-out into the slag, depending on the particle radius and physicochemical properties of the liquid steel and slag. An analysis of the calculation results of capillary force acting on a particle in the vicinity of the steel-slag interface at changing surface energy values between the precipitates and slag shows that capillary force depends on the interfacial tension between the precipitates and slag only to a small degree.