Journal Information
Vol. 7. Num. 3.July - September 2018
Pages 203-402
Share
Share
Download PDF
More article options
Visits
14
Vol. 7. Num. 3.July - September 2018
Pages 203-402
Original Article
DOI: 10.1016/j.jmrt.2018.05.024
Open Access
Review and planning of experiments with steel and slag in laboratory furnace
Visits
14
Pedro Cunha Alves
Corresponding author
pedro.c.alves@ufrgs.br

Corresponding author.
, Vinicius Cardoso da Rocha, Julio Aníbal Morales Pereira, Wagner Viana Bielefeldt, Antônio Cezar Faria Vilela
Department of Metallurgy (DEMET), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
This item has received
14
Visits
Article information
Abstract
Full Text
Bibliography
Download PDF
Statistics
Figures (5)
Show moreShow less
Tables (5)
Table 1. Chemical composition (wt.%) of the materials.
Table 2. Review of experimental parameters adopted in laboratory.
Table 3. Technical data of the operation in the resistive furnace adopted in future studies.
Table 4. Amount of materials used and interactions studied in each experiment.
Table 5. Chemical composition (wt.%) of the slags after the experiments.
Show moreShow less
Abstract

During the steel secondary refining, the elimination of impurities, adjustment of the chemical composition and adjustment of the temperature of the liquid steel occurs. The removal of non-metallic inclusions usually occurs in this step, being performed by the slag. In this work, a planning of laboratory experiments was defined so that in a second stage, the obtained knowledge can be compared with previous studies and transferred to the industrial practice. First, a review of the literature about experiments carried out in laboratory furnaces with samples with steel and slag in studies focused on the removal and/or modification of inclusions was done. Then, two experimental tests were conducted to validate the configuration adopted in the first part of this work. In the optimized experimental arrangement, the experiments will be performed in a resistive furnace with protective atmosphere granted by argon passage. The samples will be melted in MgO crucibles at 1600°C and maintained by 90min at this temperature to reach the thermodynamic equilibrium. The samples will be cooled with water and then prepared for future analyses. The review showed a promising experimental arrangement that will be used as a standard for steel and slag studies carried out in the Ironmaking and Steelmaking Laboratory, at UFRGS. In relation to the experimental tests, the results found agreed with the literature and thus, the experimental arrangement for future studies was validated. The future experiments will be done in order to achieve the optimized arrangement.

Keywords:
Secondary refining
Steel cleanliness
Resistive furnace
Inclusions
Full Text
1Introduction

The secondary refining process is one of the most important stages to obtain a high quality product. During the refining process occurs the removal of impurities, chemical composition adjustment and control of temperature of the liquid steel. In this process it is used a slag, which has a very important impact in the control of those factors. The main functions of the secondary refining slags are: absorb impurities [1,2], avoid reoxidation [3] and ensure protection against heat loss [3]. Two types of slag systems are commonly employed in this step: the CaO-SiO2-Al2O3-MgO(-CaF2) and the CaO-SiO2-Al2O3-MgO [2,4].

One of the main parameters for measuring the steel cleanliness is the control of non-metallic inclusions. Among these parameters, the most important are composition, size, morphology and distribution [5]. The demand for clean steels is getting higher every year and thus, the control of inclusions becomes increasingly important [6]. Depending on the application of the material, the control of non-metallic inclusions must be done differently, so different applications require different practices for the control of inclusions [5].

The inclusions are generally removed through absorption by the slag. In the steel production, the removal happens in the secondary refining and at the continuous casting (tundish). The removal process can be performed in three steps: (i) flotation, (ii) separation, (iii) dissolution [7]. The first step involves the transport of the inclusion to the steel/slag interface. At this interface, surface tensions are present. They must be reached to carry out the separation of the inclusion from the liquid steel. Therefore, the inclusion can be stabilized at the steel/slag interface. Finally, the inclusion is considered removed when it is fully incorporated into the slag [1,7].

Refining slags have great influence on the steel cleanliness, resulting in a decrease in the total oxygen content due to its deoxidation capability. This property could lead to a decrease in the number of inclusions [8]. Other factors that can be modified with the use of refining slags are the shape, composition, and melting point of the inclusions. Numerous studies have already been done with the objective to evaluate the influence of the chemical composition of the slags in the steel cleanliness [1,2,7,9–11].

In order to obtain a better understand and future improvements in the industrial process, a good alternative is to execute experiments with steel and slag in a laboratory furnaces. In these experiments, it is possible to study the different properties of the slag, such as its binary basicity, alumina wt.% (Al2O3), silica wt.% (SiO2) and MgO wt.% content. With a better control of these properties, it could be easier to understand their effects on the control of inclusions. A good strategy is to reach the initial knowledge in the laboratory, and then, subsequent tests in the industry to validate the results obtained [8,12–15].

The objective of this work was to design an experimental arrangement, based on a literature review, which would be adopted as a standard for laboratory experiments in the Ironmaking and Steelmaking Laboratory, at Federal University of Rio Grande do Sul (UFRGS). After choosing an optimized configuration, two experiments were done, and the results were compared with the literature to validate the experimental arrangement. A positive result would lead to future studies of secondary refining phenomena and their effects in the removal and modification of inclusions.

2Materials and methods2.1Experimental arrangement

In order to define an experimental arrangement for laboratory tests with slag and steel in secondary refining conditions, three initial steps were defined according to Fig. 1.

Fig. 1.
(0.12MB).

Flowchart used to design a table with comparative experimental data.

The first step was focused on the reading of articles selected from the literature review. In the second step, some filters were applied to reduce the number of articles in this review. Inside the second step, works done with low alloy special steels and stainless steels were selected. With this filter, it was tried to verify different experimental practices depending on the type of steel studied. In the first step, it was identified that few experiments used fluorite in the composition of the slag. So it was applied a filter to leave this factor out of the review. For this review, only the CaO-SiO2-Al2O3-MgO slag system will be evaluated. Also, studies developed with more than 1000g of steel were excluded due to the limiting factor of the size of the furnace that will be used in the future experiments. In addition, articles were chosen that had the removal and/or modification of inclusions as its main objective.

2.2Experimental tests

Two materials used in the tundish were tested to validate the experimental arrangement selected. A calcium aluminate slag and rice husk ash (RHA) were analyzed to verify the formation of inclusions because of reoxidation events. The chemical composition of these materials are presented in Table 1

Table 1.

Chemical composition (wt.%) of the materials.

Material  CaO  SiO2  Al2O3  MgO  FeO  MnO  CaF2 
Calcium aluminate slag  45.65  2.84  22.88  20.75  0.57  0.06  7.25 
Rice husk ash  0.44  95.59  –  2.58  0.87  0.53  – 

A modified SAE 1055 was used in this work; the sample was obtained after the rolling process. Two experiments were conducted; first, the interaction between steel and slag was analyzed. Then, the experiment was repeated with the addition of RHA. The experimental configuration is shown in Fig. 2.

Fig. 2.
(0.03MB).

Experimental configuration of crucible and materials.

After the experiments, an ASPEX Explorer equipped with a SEM/EDS system was used for the inclusion analysis. The inclusion density and the chemical composition of inclusions were evaluated. The total oxygen content (T.O.) in the steel was measured using a LECO TS-436 equipment. A Philips equipment, model PW2600 was used to measure the chemical composition of the materials by X-ray fluorescence. These results were compared with studies in the literature to verify if the experimental arrangement was correct to proceed with future laboratory studies focused in steel and slag experiments.

3Results and discussion3.1Parameters of the experiments

After the development of the previously steps mentioned, twelve papers were selected [4,8,10–13,16–21]. They are presented in ascending order of publication year. In Table 2, the following parameters are presented: furnace type, protective gas, type and dimensions of crucible, steel mass, slag mass, moment of slag addition, slag/steel proportion, temperature, number of experiments, time and cooling method. The parameters that can be varied depending on the objective of study are: slag mass, slag/steel proportion, number of experiments and time for withdraw of samples during the experiment. All other parameters should remain constant. The authors did not report some parameters, and then some fields in the table were not filled.

Table 2.

Review of experimental parameters adopted in laboratory.

Author  Year  Type of Furnace  Gas  Crucible and Dimension (mm)  Steel Mass (g)  Slag Mass (g)  Moment of Slag Addition  Slag/Steel Proportion  Temperature (°C)  Number of Experiments  Time (min)  Cooling 
Jiang [16]  2008  Resistive  Argon  MgO  150  30  Beginning  0.2  1600  30, 60, 90, 120 and 180  Water 
Jiang [17]  2010  Resistive  Argon  MgO  100  50  Beginning  0.5  1600  –  30, 60, 90 and 180  Water 
Jiang [10]  2010  Resistive  Argon  MgO  100  50  Beginning  0.5  1600  29  30, 60, 90 and 180  Water 
Wang [13]  2011  Resistive  Argon  MgO (Ø=30)  100  50  Beginning  0.5  1600  34  30, 60 and 90  Water 
Jiang [11]  2012  Resistive  Argon  MgO  100  50  Beginning  0.5  1600  33  90  Water 
Jiang [18]  2014  Resistive  Argon  ZrO2  150  30  Beginning  0.2  1600  30, 60, 90, 120 and 180  Water 
He [12]  2014  Resistive  Argon  MgO  200  20  Beginning  0.1  1600  13  30, 60, 90 and 120  Water 
Yu [8]  2015  –  Argon  MgO  200  40  Beginning  0.2  1600  –  90  Water 
Kumar [19]  2016  Inductive  Argon  MgO(Ø=61) ZrO2=31)  600 and 100  200 and 15  Beginning and During  0.33 and 0.15  1600  3, 25 and 35; 15, 35 and 55  Air 
Wang [4]  2016  Inductive  Argon  MgO(Ø=55)  400  70  During  0.17  1600  15, 30, 45, 60 and 90  Water 
Stephano [20]  2016  Inductive  –  MgO(Ø=58)  620  182  During  0.29  1600  5, 10, 15, 20 and 25  Air 
Li [21]  2016  Inductive  –  MgO and Al2O3  1000  50  During  0.05  1600  –  25  Air 

Afterwards, the experimental parameters mentioned in Table 2 will be analyzed and discussed in order to compose the experimental arrangement to be adopted as a standard for future experiments.

3.1.1Type of furnace and protective gas

The experiments were performed in two types of furnace: inductive and resistive. The utilization of induction furnaces is characterized by the use of higher steel and slag masses when compared to the resistive furnace. The experiments in this type of furnace have the benefit of the existence of induction lines that can cause a natural stirring in the liquid bath [22]. The literature review showed that when using induction furnaces, the steel mass varied between 400 and 1000g [4,19–21].

For resistive furnaces, the heating is done by the passage of electric current through an electric conductor, generating heat to the equipment due to the resistance of these conductors. With the passage of electric current, it may be possible to generate small magnetic fields, capable of performing a slight stirring in the liquid bath. Another phenomenon that could carry out some stirring in the liquid bath is the convection. Due to the temperature difference in the lower and upper furnace region and the presence of a protective gas during the experiments, this phenomenon would be possible to occur [22]. The use of this type of furnace was characterized by the presence of steel mass between 100 and 200g [10–13,16–18].

The experiments will be conducted at the Ironmaking and Steelmaking Laboratory, located at the UFRGS. In this laboratory, there is a high temperature resistive furnace to be used for these experiments. Some parameters of this furnace are presented in Table 3.

Table 3.

Technical data of the operation in the resistive furnace adopted in future studies.

Technical information   
Graphite tube dimensions  Diameter: 150mm; Total height: 470 mm; Working height (with insulation system coupled): 350mm 
Graphite tube volume  4.4
Maximum operation temperature  2100°C 
Heating rate  5°C/min (for T>25°C) 
Atmosphere  Inert (Argon or Nitrogen) 
Temperature measurement  Mantel-thermocouple WRe 6/25 
Cooling system  Water (inlet: ∼13°C/outlet: ∼37°C) 
Voltage/frequency  3×380 V/50–60Hz 

The high purity inert gas used will be argon, following the standard in all the experiments reviewed. The function of the inert gas will be to protect the interior of the furnace and reduce the partial pressure of O2. With a low value, it should be possible to avoid reoxidation events [23]. The partial pressure inside the furnace was estimated assuming the use of argon gas with 99.999% purity and 1ppm O2. This gas will be inside a volume of 4.4L. By the equation PV=nRT[24], the partial pressure of O2 was calculated in 1.08×10−6atm. During the literature review, it was found the value of 10−3atm for partial pressure of O2 measured with a gas analyzer. Thus, the estimated value lies in an acceptable range in order to avoid reoxidation events [23]. A suggestion for future works is the installation of a gas analyzer to measure the partial pressure of O2 during the experiments.

3.1.2Type of crucible and dimensions, steel mass, slag mass, slag addition and slag and steel proportion

The type of crucible varied in the experiments reviewed. The use of MgO, Al2O3 and ZrO2 crucibles was verified. Crucibles of MgO are the most indicated, they are similar to the type of refractory used in most of secondary refining ladles. Crucibles of Al2O3 can be used as well; therefore, it needs to pay attention to the MgO saturation. In experiments with this type of crucible, it is intended to use a chemical composition in order to obtain a slag saturated in MgO. Otherwise, the formation of MgO-Al2O3 inclusions may not occur as expected [21]. Another problem for this type of crucible is the saturation of Al2O3. If the slag is not saturated in this component, it will react with the crucible wall to reach the saturation in Al2O3. The use of ZrO2 crucibles showed the same concern about MgO saturation [18,19]. In addition, it was verified the presence of many inclusions with ZrO2 in their chemical composition [18]. The presence of those inclusions could difficult the interpretation of the results regarding industrial applications, where it is not usual the presence of inclusions with ZrO2 in its chemical composition.

It was defined that the tests will be carried out in Al2O3 or MgO crucibles. The preferred type of the crucible for the experiments will be MgO. Only four papers from the review showed the dimensions of the crucibles [4,13,19,20]. This information is not shown frequently during those studies. Thus, the definition of the dimensions of the crucibles was made based on the size of the graphite tube present in the resistive furnace that will be used. The crucibles will have an internal diameter of 20mm and a height of 50mm. This size allows the placement of eight crucibles inside the furnace in each experiment. With this size, the maximum productivity can be achieved. It was intended to put the largest number of crucibles each time the furnace was turned on. A protective graphite crucible with internal diameter of 100mm will be used to protect the samples and the interior of the furnace. This practice is used in some studies reviewed [19,20]. The steel mass will be 50g. The slag mass could vary between 5 and 12.5g, respecting the height of the crucible, and it will be added at the beginning of the experiment. Experiments with the addition of slag at the beginning could present better results regarding steel cleanliness. With the melting point of the slag smaller than steel, liquid slag will be formed before the melting of the steel sample. This condition could favor the phenomena of removal or modification of inclusions [19].

Due to the variation of slag mass, studies can be carried out to verify the influence of the slag/steel proportion during the treatment of inclusions. When this factor is not interest of study, it will be maintained constant at a value of 10g of slag. With this mass of slag, the proportion of the experiment will be 0.2. This proportion was used in some reviewed studies [4,8,16,18,19].

3.1.3Temperature, number of experiments, time and cooling

The temperature chosen for the experiments was 1600°C, this value is used in all the experiments reviewed with focus on the study of the secondary refining process [4,8,10–13,16–21].

The number of experiments ranged from 2 to 33 in the references present in this review and in some cases, this value is not reported. The future experiments will follow statistical models based on design of experiments methodology. Experiments will be carried out starting from an experimental matrix generated in a 2k factorial project. The varied factors will be chosen with the objective to verify their influence in studies with secondary refining slags. Their significance in relation to steel cleanliness will be evaluated as well. Based on a literature review, it is possible to choose the factors and levels that could be studied.

The residence time at the chosen temperature, 1600°C, will be 90min. With this time, it is desired to reach the thermodynamic equilibrium between steel and slag in a resistive furnace [16]. Studies with different times of residence can also be performed. In this case, it becomes possible to analyze the evolution of the format and composition of the inclusions during the time. For this arrangement, it is proposed the withdraw of samples in different times to perform the analyzes. All samples will be cooled in water, this practice is adopted in almost all the references reviewed [4,8,10–13,16–18].

3.1.4Optimized experimental arrangement

From the observations and definitions presented in the previous subitems, the future experiments will have as standard the following arrangement:

  • Furnace: Resistive;

  • Protective Gas: Argon;

  • Type of Crucible: MgO;

  • Number of Crucibles per Experiment: Eight;

  • Mass of Steel: 50g;

  • Mass of Slag and Moment of Addition: 10g in the beginning;

  • Slag/Steel Proportion: 0.2;

  • Temperature: 1600°C;

  • Number of Samples: chosen by 2k factorial project;

  • Time: 90min;

  • Cooling Method: Water.

Due to the dimensions of the crucible, it would be possible to use up to eight crucibles per experiment. These crucibles will be placed inside a protective graphite crucible. At 1600°C there will be liquid steel and slag inside the crucible, in case of an accident such as slag leak, the protective crucible will prevent damages to the furnace interior. Fig. 3 shows the layout of the crucibles with the samples inside the protective crucible.

Fig. 3.
(0.06MB).

Arrangement of crucibles with samples inside the protective graphite crucible.

The utilization of eight crucibles maximizes the productivity of the experiments, being possible to realize then more efficiently. The withdraw of the samples in the temperature of 1600°C should be done valuing the security of the people involved. After cooled, the samples will be prepared and analyzed according to the main objectives of the future works.

3.2Experimental results

As it was explained before, two experiments were conducted to verify the experimental arrangement. For these experiments, three different parameters from the optimized arrangement were used. The material of the crucible was alumina, since the use of MgO crucible was postponed because of the difficulty to find a provider for this type of crucible in Brazil. The temperature chosen was 1580°C because this is the approximately temperature of the steel during the tap operation from the ladle furnace to the tundish. The samples were cooled inside the furnace to avoid air contamination that could lead to unwanted reoxidation events. Table 4 presents the amount of steel, material and the interactions analyzed.

Table 4.

Amount of materials used and interactions studied in each experiment.

Experiment  Interaction  Steel (g)  Material (g) 
Steel-tundish slag  150  20 
Steel-tundish slag-RHA  150  20 and 5 

The silicon (Si) content in the steel sample was measured to verify its variation. The literature shows that the increase of SiO2 in the tundish slag would increase the Si content [23,25–27]. The presence of RHA, a silica based material, increased the Si content in experiment B from 0.220 (original sample) to 0.310wt.%. Experiment A, with low SiO2 content, presented a final value of 0.186wt.% of Si. The first parameter analyzed for the inclusions was their chemical composition. Their values were plotted in a CaO-Al2O3-SiO2 ternary diagram and the result is presented in Fig. 4. Experiment B had an increase in the average SiO2 content in the inclusions, thus an oxide system with SiO2 was chosen for the analysis of chemical composition.

Fig. 4.
(0.29MB).

CaO-Al2O3-SiO2 ternary diagram with the chemical composition of inclusions. (a) Initial steel sample; (b) Experiment A; (c) Experiment B.

The composition of inclusions in the initial steel sample, Fig. 4(a) presented mostly alumina silicate inclusions, also a good steel cleanliness is observed. Experiments A and B presented different types of inclusions than that observed in the initial sample, indicating that the inclusions observed in these experiments were formed by reoxidation. Related to the types of inclusions observed in Fig. 4(b) and (c), experiment A presented mostly alumina inclusions, Fig. 4(b). It is important to note that the calcium aluminate slag used in the experiments reacted with the crucible to reach the saturation in alumina. This effect probably generated numerous pure alumina inclusions. In the other hand, the experiment B had the formations of many oxide inclusions in the CaO-Al2O3-SiO2 oxide system, being detrimental to the quality of the steel. The presence of RHA increased the SiO2 content of the slag. This would lead to the formation of numerous inclusions with Al2O3 in their composition [23,25,27,28]. This result is confirmed in Fig. 4(c). Both experiments increased the number of inclusions, being harmful to the steel cleanliness. The chemical composition of the slag after the experiments are presented in Table 5.

Table 5.

Chemical composition (wt.%) of the slags after the experiments.

Experiment  CaO  SiO2  Al2O3  MgO  FeO  MnO  CaF2 
26.29  3.70  54.43  11.71  1.20  0.23  2.44 
29.90  12.84  41.82  10.89  1.02  0.37  3.16 

Results in Table 5 show that the slags reacted with the crucible increasing the content of Al2O3 in their composition. Yan et al. [23] used a calcium aluminate slag in alumina crucible and verified this increase in the Al2O3 content as well. The experiment with RHA had a lower value for this element. In the literature, it is observed that the increase in the SiO2 content in the slag reduces the Al2O3 content [23,27]. The presence of RHA appears to reduce the reaction between the slag and the crucible, thus presenting a lower content of Al2O3 in the final chemical composition for experiment B. Excluding the pure alumina inclusions, the experiment without the presence of RHA presented a better steel cleanliness. The use of only a calcium aluminate slag is preferable during the tundish metallurgy in order to achieve a better final product. The presence of RHA would lead to higher reoxidation events, and a decrease in the capability of inclusion removal [29,30]. The inclusion density was the other property analyzed to verify the formation of new inclusions. Four ranges of inclusion diameter were analyzed: 0.5–2.5, 2.5–5, 5–15 and ≥15μm. Fig. 5 shows the results for this analysis.

Fig. 5.
(0.07MB).

Inclusion density for the initial steel sample, experiment A and experiment B.

The initial steel sample presented a total inclusion density of 1.30mm−2. Furthermore, none inclusion with diameter above 15μm is observed. Inclusion in this range are detrimental to the mechanical properties and should be avoided during the steel production [6,31]. Both experiments presented a total inclusion density greater than the observed in the initial steel sample, with the experiment B presenting the higher value. The presence of RHA in the experiment B increased the inclusion density from 4.50 to 14.80mm−2. Kim et al. [27] and Yan et al. [23] verified an increase in the number and size of inclusions with the increase in the SiO2 of the slag. The presence of inclusions ≥15μm is another harmful effect and should be avoided. In the experiment B, many inclusions were observed in this range. Experiment A, with only the calcium aluminate slag, presented mostly inclusions between 0.5–5μm and none inclusion with diameter >=15μm. These results are similar with the initial sample, which presented an adequate steel cleanliness according to the literature [6,31]. From the results presented until now, it is confirmed that the tundish materials could be responsible for reoxidation events, being capable to deteriorate the cleanliness obtained before the tundish steelmaking. In order to diminish reoxidation events in the tundish steelmaking, it is preferable to use only a calcium aluminate slag, without the presence of RHA.

An important aspect that was pointed out in the parameters review was the oxygen partial pressure. Despite that the experimental arrangement did not present an equipment to measure this property, it was proposed a theoretical value for the furnace used in the experiments. The total oxygen content (T.O.) was measured for both experiments to verify a possible contamination because of the furnace atmosphere. The initial T.O. of the steel samples was 13ppm. Experiment A and B presented 11 and 7ppm, respectively. This value decreased for both configurations and proves that the atmosphere granted by the passage of argon gas was effective in providing a low oxygen partial pressure.

4Final considerations

With the realization of an individual analysis about each parameter that could affect the accomplishment of experiments in laboratory, it was possible to reach a suitable experimental arrangement for future works. This arrangement will be adopted as standard in the Ironmaking and Steelmaking Laboratory. With the development of these experiments, it is expected that the laboratory acquire practice in this area of research, which is very promising in the coming years. With the increase in the recycle of recently produced steels, there is a possibility that the concentration of some elements could be higher than nowadays in the secondary refining process. Those elements cannot be eliminated during the selective oxidation in the primary refining. Then with a higher concentration in the secondary refining, it may be responsible for the appearance of inclusions that still need a better understanding in the processes of removal and modification. Therefore, the realization of experiments in laboratory aiming to reach fully acknowledgment about these inclusions presents a field of research very prospective in the future.

Another field of research, which was the aim of the experimental tests, is the reoxidation of steel in the tundish. With the demand of special steels increasing every year, the presence of an active slag in the tundish is desirable in future years. Beyond the common functions desired nowadays, a tundish slag should be capable to provide one more step for the removal of inclusions before the casting process. The results presented in this work were in a good agreement with the literature. Thus, the experimental arrangement selected proved to be effective for the future studies in laboratory conditions with the presence of steel and slag.

Conflicts of interest

The authors declare no conflicts of interest.

Acknowledgements

The authors are grateful for financial support provided by the Coordination for the Improvement of Higher Education Personnel (CAPES) and the Federal University of Rio Grande do Sul (UFRGS).

References
[[1]]
B.H. Reis,W.V. Bielefeldt,A.C.F. Vilela
Efficiency of inclusion absorption by slags during secondary refining of steel
ISIJ Int, 54 (2014), pp. 1584-1591
[[2]]
V.C. Rocha,J.A.M. Pereira,A. Yoshioka,W.V. Bielefeldt,A.C.F. Vilela
Evaluation of secondary steelmaking slags and their relation with steel cleanliness
Metall Mater Trans B, 48 (2017), pp. 1423-1432
[[3]]
R.J. Fruehan
Unique functions of slags in steelmaking
VII International Conference on Molten Slags Fluxes and Salts, The South African Institute of Mining and Metallurgy, (2004)pp. 263-270
[[4]]
Q. Wang,L. Wang,K. Chou
Effect of Al2O3 content in top slag on cleanness of stainless steel Fe-13Cr. In: Advances in Molten Slags, Fluxes, and Salts
Proceedings of the 10th international conference on molten slags, fluxes and salts, pp. 155-163
[[5]]
E.B. Pretorius,H.G. Oltmann,B.T. Schart
An overview of steel cleanliness from an industry perspective
AISTech conference proceedings, pp. 993-1026
[[6]]
L.F. Zhang,B.G. Thomas
State of the art in evaluation and control of steel cleanliness
ISIJ Int, 43 (2003), pp. 271-291
[[7]]
M. Valdez,G.S. Shannon,S. Sridhar
The ability of slags to absorb solid oxide inclusions
ISIJ Int, 46 (2006), pp. 450-457
[[8]]
H.X. Yu,X.H. Wang,J. Zhang,W.J. Wang
Characteristics and metallurgical effects of medium basicity refining slag on low melting temperature inclusions
J Iron Steel Res Int, 22 (2015), pp. 573-581
[[9]]
L.E.K. Holappa,A.S. Helle
Inclusion control in high-performance steels
J Mater Process Technol, 53 (1995), pp. 177-186
[[10]]
M. Jiang,X.H. Wang,W.J. Wang
Control of non-metallic inclusions by slag-metal reactions for high strength alloying steels
Steel Res Int, 81 (2010), pp. 759-765
[[11]]
M. Jiang,X.H. Wang,W.J. Wang
Study on refining slags targeting high cleanliness and lower melting temperature inclusions in Al killed steel
Ironmak Steelmak, 39 (2012), pp. 20-25
[[12]]
X.F. He,X.H. Wang,S.H. Chen,M. Jiang,F.X. Huang,W.J. Wang
Inclusion composition control in tyre cord steel by top slag refining
Ironmak Steelmak, 41 (2014), pp. 676-684
[[13]]
X. Wang,M. Jiang,B. Chen,W. Wang
Study of non-metallic inclusions in high strength alloy steel refined by using high basicity and high Al2O3 content slag
Advanced steels, (2011)pp. 485-494
[[14]]
J.H. Park
Thermodynamic investigation on the formation of inclusions containing MgAl2O4 spinel during 16Cr-14Ni austenitic stainless steel manufacturing processes
Mater Sci Eng A, 472 (2008), pp. 43-51
[[15]]
S.H. Chen,M. Jiang,X.F. He,X.H. Wang
Top slag refining for inclusion composition transform control in tire cord steel
Int J Miner Metall Mater, 19 (2012), pp. 490-498
[[16]]
M. Jiang,X. Wang,B. Chen,W. Wang
Formation of MgO•Al2O3 inclusions in high strength alloyed structural steel refined by CaO–SiO2-Al2O3–MgO slag
ISIJ Int, 48 (2008), pp. 885-890
[[17]]
M. Jiang,X. Wang,B. Chen,W. Wang
Laboratory study on evolution mechanisms of non-metallic inclusions in high strength alloyed steel refined by high basicity slag
ISIJ Int, 50 (2010), pp. 95-104
[[18]]
M. Jiang,X.H. Wang,J.J. Pak
Formation of low-melting-point inclusions in Al-deoxidized steel refined by high-basicity calcium aluminate slag in ZrO2 crucible experiments
Metall Mater Trans B, 45 (2014), pp. 1248-1259
[[19]]
D. Kumar,P.C. Pistorius
A study on calcium transfer from slag to steel and its effect on modification of alumina and spinel inclusions
Advances in molten slags, fluxes, and salts: proceedings of the 10th international conference on molten slags, fluxes and salts, (2016)pp. 145-154
[[20]]
S.P.T. Piva,P.C. Pistorius
Effect of ladle furnace slag composition in Si-Mn killed
Advances in molten slags, fluxes, and salts: proceedings of the 10th international conference on molten slags, fluxes and salts, pp. 117-126
[[21]]
J.Z. Li,M. Jiang,X.F. He,W. Sun,X.H. Wang
Investigation on nonmetallic inclusions in ultra-low-oxygen special steels
Metall Mater Trans B, 47 (2016), pp. 2386-2399
[[22]]
J. Grzella,P. Sturm,J. Krüger,M.A. Reuter,K. Carina,T. Probst
Metallurgical furnaces
Wiley-VCH, (2008)
[[23]]
P. Yan,S. Arnout,M.A. Van Ende,E. Zinngrebe,T. Jones,B. Blanpain
Steel reoxidation by gunning mass and tundish slag
Metall Mater Trans B, 46 (2015), pp. 1242-1251
[[24]]
B.E. Poling,J.M. Prausnitz,J.P. O’connell
McGraw-Hill, (2001)
[[25]]
H. Tanaka,R. Nishihara,R. Miura,R. Tsujino,T. Kimura,T. Nishi
Technology for cleaning of molten steel in tundish
ISIJ Int, 34 (1994), pp. 868-875
[[26]]
K. Sasai,Y. Mizukami
Reoxidation behavior of molten steel in tundish
ISIJ Int, 40 (2000), pp. 40-47
[[27]]
T.S. Kim,Y. Chung,L. Holappa,J.H. Park
Effect of rice husk ash insulation powder on the reoxidation behavior of molten steel in continuous casting tundish
Metall Mater Trans B, 48 (2017), pp. 1736-1747
[[28]]
N. Bessho,H. Yamasaki,T. Fujii,T. Nozaki,S. Hiwasa
Removal of inclusion from molten steel in continuous casting tundish
ISIJ Int, 32 (1992), pp. 157-163
[[29]]
L. Holappa,S. Nurmi,S. Louhenkilpi
Role of slags in steel refining: is it really understood and fully exploited?
ATS international steelmaking conference, pp. 9-20
[[30]]
L. Holappa,M. Kekkonen,S. Louhenkilpi,R. Hagemann,C. Schröder,P. Scheller
Active tundish slag
Steel Res Int, 84 (2013), pp. 638-648
[[31]]
C. Capurro,C. Cerrutti,C. Cicutti
Influence of vacuum degassing on steel cleanliness
9th international conference on clean steel,

Paper was part of technical contributions presented in the events part of the ABM Week 2017, October 2nd to 6th, 2017, São Paulo, SP, Brazil.

Copyright © 2018. Brazilian Metallurgical, Materials and Mining Association
Journal of Materials Research and Technology

Subscribe to our Newsletter

Article options
Tools
Cookies policy
To improve our services and products, we use cookies (own or third parties authorized) to show advertising related to client preferences through the analyses of navigation customer behavior. Continuing navigation will be considered as acceptance of this use. You can change the settings or obtain more information by clicking here.