scholarly journals The Spontaneous Emulsification of Entrained Inclusions During Casting of High Aluminum Steels

2021 ◽  
Author(s):  
Akalya Raviraj ◽  
Nadia Kourra ◽  
Mark A. Williams ◽  
Gert Abbel ◽  
Claire Davis ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Slag Phase ◽  
Continuous Caster ◽  
Casting Process ◽  
Inclusion Size ◽  
Confocal Scanning Laser Microscopy ◽  
Continuous Casting Mold ◽  
Spontaneous Emulsification ◽  
Mold Slag ◽  
High Aluminum

AbstractMold slag entrainment during the continuous casting process presents a late stage source of non-metallic inclusions (NMI) with a high likelihood of ending up in the final product. The reaction between the entrained slag phase and surrounding liquid steel in the continuous casting mold affects the inclusion morphology and properties. However, there is a lack of information on the kinetics of the NMI-steel reaction. A novel approach, utilizing controlled synthetic inclusion/metal samples, has been developed to study the reactions between free inclusion-slag droplets and steel. The technique combines High-Temperature Confocal Scanning Laser Microscopy (HT-CSLM), X-ray Computed Tomography (XCT) and advanced electron microscopy techniques offering rapid controlled heating performance and extensive characterization of the samples. This method offers the ability to observe the size, shape and composition of an unconstrained reacting inclusion and to investigate the interface between the materials with respect to reaction time. This study interrogates a low aluminum steel (0.04 wt pct) and a high aluminum steel (1 wt pct) in contact with an inclusion-slag phase with a starting composition aligned to a typical mold slag. It was found that the reaction between silica and aluminum across the interface of the two phases provided a driving force for spontaneous emulsification to occur. Products of such emulsification will have a significant effect on the inclusion size distribution and potentially the prevalence of inclusion retention in molten steels solidifying in the continuous caster (for example if emulsified buoyancy forces are reduced to near zero) and hence in the subsequent solid product.

scholarly journals Numerical Simulation of Fluid Flow, Heat Transfer, Species Transfer, and Solidification in Billet Continuous Casting Mold with M-EMS

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 66 ◽  
Author(s):  
Wenjie Zhang ◽  
Sen Luo ◽  
Yao Chen ◽  
Weiling Wang ◽  
Miaoyong Zhu
Keyword(s):  
Fluid Flow ◽  
Continuous Casting ◽  
Swirling Flow ◽  
Casting Process ◽  
Longitudinal Section ◽  
Current Intensity ◽  
Continuous Casting Mold ◽  
Casting Mold ◽  
Billet Continuous Casting ◽  
Negative Segregation

Electromagnetic stirring in mold (M-EMS) has been widely used in continuous casting process to improve the solidification quality of the steel strand. In the present study, a 3D multi-physical-field mathematical model was developed to predict the macro transport phenomena in continuous casting mold with M-EMS using ANSYS commercial software, and was adopted to investigate the effect of current intensity (0, 150, 200, and 240 A) on the heat, momentum, and species transports in the billet continuous casting mold with a size of 160 mm × 160 mm. The results show that when the M-EMS is on, the horizontal swirling flow appears and shifts the high-temperature zone upward. With the increase of current intensity, two swirling flows form on the longitudinal section of continuous casting mold and become more intensive, and the flow velocity of the molten steel at the solidification front increases. Thus, the wash effects of the fluid flow on the initial solidified shell become intensive, resulting in a thinner shell thickness at the mold exit and a significant negative segregation of carbon at the billet subsurface.

Effect of Bottom Structure of Submerged Entry Nozzle on Flow Field in Ultra-Thick Slab Continuous Casting Mold

2010 ◽  
Vol 154-155 ◽  
pp. 840-845 ◽  
Author(s):  
Xin Xie ◽  
Deng Fu Chen ◽  
Qiang Liu ◽  
Jia Long Shen ◽  
Zheng Peng ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Flow Pattern ◽  
Submerged Entry Nozzle ◽  
Casting Process ◽  
Surface Flow ◽  
Water Model ◽  
Continuous Casting Mold ◽  
Flat Bottom ◽  
Thick Slab ◽  
Flow Intensity

Submerged entry nozzle (SEN) bottom structure plays an important role in determining the flow pattern in continuous casting process. This work applies a water model to evaluate the pointed-bottom, flat-bottom and recessed-bottom nozzle performance in ultra-thick slab mold. The jet properties and surface flow are compared for the three kinds of nozzles quantitatively. The results show that flat-bottom and recessed-bottom nozzles are similar in flow pattern, but the pointed-bottom nozzle has smaller jet angle, thinner flow pattern, larger surface asymmetry rate, and higher surface flow intensity.

scholarly journals Comparison of the Microstructure of M2 Steel Fabricated by Continuous Casting and with a Sand Mould

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 560
Author(s):  
Jinwen Zhang ◽  
Zhigang Zhao ◽  
Wenxian Wang ◽  
Yutian Wang
Keyword(s):  
Grain Size ◽  
Continuous Casting ◽  
Cooling Rate ◽  
Continuous Caster ◽  
Casting Process ◽  
Sand Mold ◽  
Average Grain Size ◽  
Kg Medium ◽  
The Relationship ◽  
Continuous Casting Billet

AISI M2 steel was smelted in a 150 kg medium-frequency induction furnace and cast to form round billets with a cross-section diameter of 100 mm via a vertical continuous caster and sand mold. The secondary dendrite arm spacing (λ2), cooling rates, permeability and size and distribution of grains and network carbides of the two billets were studied. The results show that the continuous casting process can effectively decrease the λ2 value, permeability and size of the grains and carbides and improve the distribution of the grains and carbides during solidification. The λ2 values of the billets cast with a sand mold and continuous caster are 37.34 μm and 21.14 μm, respectively, and the cooling rate is 3.6 K·s−1 and 12.0 K·s−1, respectively. The area fractions of carbides at the center of the billets cast with the sand mold and continuous caster are 0.24 and 0.16, respectively, and increase by 27.7% and 25.4%, respectively, compared with their average values. The average grain size of billets cast with the sand mold and continuous caster is 69.4 μm and 50.5 μm, respectively. Compared with the sand mold billet, the grain size at the center of the continuous casting billet is reduced by 25.5%. The relationship between the grain size and cooling rate is presented in this paper.

scholarly journals Control of Crystal Morphology for Mold Flux During High-Aluminum AHSS Continuous Casting Process

2016 ◽  
Vol 47 (4) ◽  
pp. 2211-2221 ◽  
Author(s):  
Jing GUO ◽  
Myung-Duk SEO ◽  
Cheng-Bin SHI ◽  
Jung-Wook CHO ◽  
Seon-Hyo KIM
Keyword(s):  
Continuous Casting ◽  
Mold Flux ◽  
Crystal Morphology ◽  
Casting Process ◽  
Continuous Casting Process ◽  
High Aluminum

scholarly journals Method of Verification of Carbon Segregation Ratio Determined with Experimental Methods

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 499
Author(s):  
Jan Falkus ◽  
Katarzyna Miłkowska-Piszczek ◽  
Paweł Krajewski ◽  
Tomasz Ropka
Keyword(s):  
Continuous Casting ◽  
Continuous Caster ◽  
High Carbon Steel ◽  
Metal Flow ◽  
Casting Process ◽  
Segregation Ratio ◽  
Carbon Steels ◽  
High Carbon ◽  
Continuous Casting Process ◽  
Carbon Segregation

The problem of macrosegregation of alloying elements occurring during cast strand solidification in the continuous casting process is still valid; it is the subject of numerous experiments and theoretical considerations. A large percentage of this research is dedicated to carbon segregation, which, for understandable reasons, is vital for the production of high-carbon steels. The background knowledge on the mechanism of segregation occurrence indicates that it is a very complex effect, and a broad range of factors influencing the continuous casting process need to be considered. Therefore, it is difficult to translate information (provided by complex models of metal flow through a diphase area at the solidification interface of a cast strand) into practical engineering recommendations to reduce the macrosegregation effect. The presented study shows the latest research related to the carbon macrosegregation effect for selected high-carbon steel grades cast with a continuous caster. Problems related to the recording of the effect concerned have been pointed out. The second part of the paper presents the influence of selected casting parameters on carbon macrosegregation intensity when casting 160 × 160 billets with a six-strand caster. In this case, the main subject of the research was the influence of the casting speed on macrosegregation intensity. In the following step, an attempt was made to find the relationship between the cast strand structure and the distribution of carbon content on its cross-section. The ultimate objective of the presented study was to find an answer to the question on the technological capabilities of restricting the segregation effect.

Development and Application of CISDI Online Slab Quality Diagnosis & Analysis System

2012 ◽  
Vol 542-543 ◽  
pp. 647-652
Author(s):  
Shui Gen Wang ◽  
Ke Feng ◽  
Zhi Wei Han ◽  
Yi Wen Kong ◽  
Jian Feng Cao
Keyword(s):  
Continuous Casting ◽  
Process Analysis ◽  
Continuous Caster ◽  
Casting Process ◽  
Internal Crack ◽  
Quality Level ◽  
Strain Calculation ◽  
Solidification Simulation ◽  
Analysis System ◽  
Quality Diagnosis

An online slab quality diagnosis & analysis system named CISDI_SQDS ONLINE R2011 has been presented in this paper. The system is based on mechanism of defects, which mainly refer to surface crack & internal crack, heat-transfer & solidification simulation, stress & strain calculation and metallurgical process analysis about continuous casting. Combining with BP neural network, several kinds of quality loss factors are used to describe the possibility of inducement. Meanwhile, the respective crack formation indexes are introduced to be the theoretical reference data for slab quality level evaluation and guiding production. The CISDI_SQDS ONLINE R2011 system was firstly applied on the No.1 Slab Continuous Caster of Bayi Steel in China. It is preliminary proved that the model is reliable and reasonable. It can be widely used as an important theoretical tool for prediction & control for slab quality in continuous casting process.

The Influence of Argon Flow on Inclusion Characteristic and Fatigue Life of Continuous Casting Bearing Steels

2011 ◽  
Vol 418-420 ◽  
pp. 972-976
Author(s):  
Chin Chuan Hsu ◽  
Ho Hua Chung
Keyword(s):  
Fatigue Life ◽  
Continuous Casting ◽  
Extreme Values ◽  
Energy Dispersive Spectrometer ◽  
Casting Process ◽  
Inclusion Size ◽  
Bearing Steel ◽  
Inclusion Type ◽  
Bearing Steels ◽  
Argon Flow

In this study, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) are used to measure the inclusion size and identify the inclusion type respectively. The evaluated maximum nonmetallic inclusion size of bearing steel has been obtained by using statistics of extreme values (SEV). The influence of argon flow of the continuous casting process on the inclusion characteristics of bearing steels has been estimated, the influence of size and type of inclusion of bearing steel on its fatigue life have been discussed as well. It was found that most inclusions in steels are oxysulfide and alumina cluster. With the decreasing of the argon flow, the inclusion size gets larger and the amount of cluster-type inclusion also increases. In addition, by adopting the criterion of return period (T) at 200, the serial analyses show that the relation between predicted inclusion size for max and the argon flow is inverse proportion, but the fatigue life of steel is proportional to argon flow. A correlation among argon flow, inclusion size and fatigue life of bearing steel has been established in this study.

scholarly journals Optimization of the Continuous Casting Process of Hypoeutectoid Steel Grades Using Multiple Linear Regression and Genetic Programming—An Industrial Study

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 972
Author(s):  
Miran Brezocnik ◽  
Uroš Župerl
Keyword(s):  
Tensile Strength ◽  
Continuous Casting ◽  
Continuous Caster ◽  
Continuous Casting Machine ◽  
Casting Machine ◽  
Casting Process ◽  
Continuous Casting Process ◽  
Strength Tests ◽  
Steel Grades ◽  
Hypoeutectoid Steel

Štore Steel Ltd. is one of the major flat spring steel producers in Europe. Until 2016 the company used a three-strand continuous casting machine with 6 m radius, when it was replaced by a completely new two-strand continuous caster with 9 m radius. For the comparison of the tensile strength of 41 hypoeutectoid steel grades, we conducted 1847 tensile strength tests during the first period of testing using the old continuous caster, and 713 tensile strength tests during the second period of testing using the new continuous caster. It was found that for 11 steel grades the tensile strength of the rolled material was statistically significantly lower (t-test method) in the period of using the new continuous caster, whereas all other steel grades remained the same. To improve the new continuous casting process, we decided to study the process in more detail using the Multiple Linear Regression method and the Genetic Programming approach based on 713 items of empirical data obtained on the new continuous casting machine. Based on the obtained models of the new continuous casting process, we determined the most influential parameters on the tensile strength of a product. According to the model’s analysis, the secondary cooling at the new continuous caster was improved with the installation of a self-cleaning filter in 2019. After implementing this modification, we performed an additional 794 tensile tests during the third period of testing. It was found out that, after installation of the self-cleaning filter, in 6 steel grades out of 19, the tensile strength in rolled condition improved statistically significantly, whereas all the other steel grades remained the same.

scholarly journals On Modelling Parasitic Solidification Due to Heat Loss at Submerged Entry Nozzle Region of Continuous Casting Mold

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1375
Author(s):  
Alexander Vakhrushev ◽  
Abdellah Kharicha ◽  
Menghuai Wu ◽  
Andreas Ludwig ◽  
Yong Tang ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Steel Slag ◽  
Phase Interface ◽  
Steel Production ◽  
Submerged Entry Nozzle ◽  
Casting Process ◽  
Material Model ◽  
Slag Layer ◽  
Continuous Casting Mold ◽  
High Production Rate

Continuous casting (CC) is one of the most important processes of steel production; it features a high production rate and close to the net shape. The quality improvement of final CC products is an important goal of scientific research. One of the defining issues of this goal is the stability of the casting process. The clogging of submerged entry nozzles (SENs) typically results in asymmetric mold flow, uneven solidification, meniscus fluctuations, and possible slag entrapment. Analyses of retained SENs have evidenced the solidification of entrapped melt inside clog material. The experimental study of these phenomena has significant difficulties that make numerical simulation a perfect investigation tool. In the present study, verified 2D simulations were performed with an advanced multi-material model based on a newly presented single mesh approach for the liquid and solid regions. Implemented as an in-house code using the OpenFOAM finite volume method libraries, it aggregated the liquid melt flow, solidification of the steel, and heat transfer through the refractory SENs, copper mold plates, and the slag layer, including its convection. The introduced novel technique dynamically couples the momentum at the steel/slag interface without complex multi-phase interface tracking. The following scenarios were studied: (i) SEN with proper fiber insulation, (ii) partial damage of SEN insulation, and (iii) complete damage of SEN insulation. A uniform 12 mm clog layer with 45% entrapped liquid steel was additionally considered. The simulations showed that parasitic solidification occurred inside an SEN bore with partially or completely absent insulation. SEN clogging was found to promote the solidification of the entrapped melt; without SEN insulation, it could overgrow the clogged region. The jet flow was shown to be accelerated due to the combined effect of the clogging and parasitic solidification; simultaneously, the superheat transport was impaired inside the mold cavity.

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