9th International Conference on Modeling and Simulation of Metallurgical Processes in Steelmaking - STEELSIM2021

Continuous casting of steel is an important commercial process that involves many complex, coupled physical phenomena, which have been the subject of significant computational modeling efforts over the past half-century. This paper summarizes the current state of the art in modeling and simulation of these phenomena. This includes models of heat transfer and solidification of the steel shell,...

Throughout the entire steelmaking production process, refractory materials play a key role. The functionalities of these materials are manifold, such as maintaining the integrity of furnace vessels and protecting the steel shells from high temperatures, therefore regulating temperature losses. The materials also guarantee a safe transfer of liquid steel from one operational unit to another...

Johannes Kreyca*, Sabine Zamberger – voestalpine Forschungsservicegesellschaft Donawitz GmbH, Kerpelystr. 199, A-8700, Austria
Matthew Galler – voestalpine Wire Rod Austria GmbH, Drahtstraße 1
8792 St. Peter-Freienstein, Austria
Ernst Kozeschnik – TU Wien, Getreidemarkt 9, 1060 Wien, Austria

*Corresponding: Johannes.kreyca@voestalpine.com

ABSTRACT

The combination of traditional...

In metallurgy, gas is often injected into melts for mixing, degassing or refining. The knowledge of the two-phase flow behaviour is of utmost relevance for optimisation and process control. However, the measurement of the flow structure, the gas distribution and the characteristics of the bubbles is very challenging, because of the opaqueness and the high temperature of industrial relevant...

The burden distribution in the blast furnace has a major impact on the process and its stability. The iron bearing burden consists normally of several components, such as sinter, pellets, lump ore, silica addition and nut coke. Therefore, the exact composition at discrete positions and times in the blast furnace is of great interest. While the charging via a rotating chute is well investigated...

Injecting pulverized coal into the raceway zone of blast furnaces is a stat of the art process to optimize the operation of the furnace. Modeling the thermo chemical conversion of pulverized coal in the raceway zone is commonly used to investigate its effect on the blast furnace process or to optimize the coal injection process. The quality and accurateness of the employed models determine the...

In the processing of heavy plates, the leveling operation aims at improving the plate flatness and minimizing residual stresses, but is also the last process step influencing the strength properties in a significant manner. To this end, the roller-leveling machine applies multiple cycles of plastic bending with a strain sequence depending on the actual leveler setup to the plate cross section...

The bubble breakup and coalescence behavior and mechanisms in gas-stirred ladle were studied by establishing physical model and mathematical model. The mechanisms of bubble breakup and coalescence in the gas-stirred ladle and their influence on bubble size distribution were revealed. The results show that the bubble breaking behavior has little effect on bubble size and distribution. The...

The Direct Reduction (DR) of iron ore pellets with syngas or hydrogen is a promising technology to reduce the emission of iron making. The conversion rate of singe pellets to iron has been extensively investigated. A shrinking core model is commonly employed to reproduce the experimental observations.
Though, this model presents an inherent bias by assuming a sharp separation between a fully...

Steel industry, even with best operating practices, has reported a minimum of 2 to 3 ppm nitrogen absorption, during transfer of molten steel from a ladle to tundish; up to 20 ppm of nitrogen absorption is not uncommon and have also been reported in literature. These imply that ladle shroud- collector plate nozzle (LS-CN) in practice is never perfectly secured and air ingression during ladle...

The mechanical properties of steels are influenced by their microstructure and particularly the grain size, with a small grain size giving high strength and toughness. A significant process for grain size control is recrystallisation during hot rolling, where the recrystallisation kinetics and recrystallised grain size are affected by the material’s initial grain size, alloy content,...

Non-metallic inclusions generated by mold flux entrapment are detrimental to the final steel’s quality. In this paper, a water model experiment was carried out to study the mold flux entrapment during the filling process. The side outlet was created at the mold to ensure the quasi-steady state of the filling process, which can help to visualize the formation of the open eye. Additionally,...

Hot-dip galvanizing (HDG) Zn coatings represent a low cost and effective way of protecting steel against corrosion. In recent years, Zn coatings containing Mg became a promising next generation of Zn-based coatings due to their superior performance compared to pure Zn coatings in terms of corrosion resistance, formability, weldability and paintability [1].

These properties are strongly...

The thermo-chemical conversion of coke and reduction of iron ore particles both depend on mass transport from the bulk fluid phase towards the reactive sites in the solid phase. Pore diffusion limits this mass transport in porous particles at intermediate temperatures, while chemistry is limiting co
nversion rates at low temperatures. Besides temperature, pore diffusion rates also depend on...

Lowering emissions of pollutants and carbon consumption has become increasingly imperative in our society nowadays. The worldwide growing restrictions of waste gas emissions on integrated steelworks are the focal motivation of this work. The sintering process is a highly energy-intensive, and a vast material-consuming process unit in the hot metal production. Iron ore sintering depends on the...

This work presents novel results on factors influencing austenite stability in carburised high carbon bearing steels. We have conducted a series of experimental and computational studies targeted at understanding these factors, including chemical composition, austenite grain size, stress/strain partitioning, and grain orientation.
In-situ neutron diffraction in steels with different nickel...

The recent development of data-assisted recurrence CFD (rCFD) has boosted the computational performance of CFD simulations by orders of magnitude. In a recent publication (Pirker et al, SRIN, 2020), we presented real-time simulations of multiphase fluid flow and alloy homogenization in a RH vacuum treatment plant on a computational grid of more than three million cells.

This computational...

In additive manufacturing of metals, high quality powder with uniform size distribution and spherical, satellite-free particles of defined size is required. SMS group has built-up a metal powder production plant which operates using the close-coupled atomization principle. For reliable plant operation, it is important to understand the atomization mechanisms, i.e. the effect of plant...

High-value speciality steels are often designed for specific large component engineering applications. These steels, which are typically heavily alloyed, offer excellent properties in terms of fatigue, toughness, high-temperature strength and corrosion resistance. However, due to the fact steelmakers are at the start of a multi-partner supply chain, feedback regarding component manufacture and...

Flow in the tundish region during the continuous casting of steel can influence many important phenomena, especially removal of the non-metallic inclusions. If they are not removed from the steel melt during its processing, it can reduce the quality of the finished steel product. Therefore, in this study, the complex numerical modelling in the CFD programme ANSYS Fluent was used for detection...

Increasing interest in the direct reduction of Iron has revived investigations on the kinetics of gaseous reduction of iron oxides. Despite extensive investigations on the reduction of iron oxides with pure hydrogen or with syngas, the development of a generic reduction mechanism of iron oxides is still lacking. The conventional shrinking core model hardly distinguish between transport...

The high heat input welding method can improve the efficiency of manufacturing, but the impact toughness of the heat-affected zone (HAZ) is reduced seriously during the welding process. Thermal profile evolution in HAZ is the key factor affect microstructures and resulting mechanical properties of welded joints.

In this study, we coupled heat transfer, solid mechanics and solid-state...

The current work and paper bases on a new iron production route which uses iron ore fines direct reduction. This technology was invented by ENRAG and PRIMETALS and is in ongoing development by Primetals Technology. It is called HYFOR. This new direct reduction technology uses iron ore fines instead of pellets and is therefore more energy efficient and uses cheaper ore material compared to...

Quenching and partitioning (Q&P) process [1] is a heat treatment to produce steels with high strength and ductility. Chemical composition and process parameters control the final phase composition of a Q&P steel, thereby influencing its mechanical properties [2]. The objective of this work is to analyse computationally the effect of the composition and process parameters on the mechanical...

In continuous casting of steel, argon injection into the SEN (submerged entry nozzle) via the stopper is common practice. Nonetheless, the resulting phase distribution in the SEN is still under discussion. The main available casting parameters at the steel plant to determine the flow situation in the SEN, are usually the stopper rod position, the argon feeding pressure, the mass flow rate of...

The dynamics of co-current liquid-gas flow controls the flow patterns and phase distribution inside the submerged entry nozzle (SEN) in the continuous casting. According to the flow parameters during the argon gas injection, the unsteady two-phase flow in the SEN experiences different regimes from bubbly flow to annular flow. This regime transition is usually associated with a hysteresis...

Hypereutectoid steels are of major importance for the railway and cable industry due to their good hardness and toughness. In-depth understanding of the link between their microstructure and mechanical properties presents therefore a significant industrial relevance. We have realized the multiscale modelling of macroscopic elastic properties of hypereutectoid steel based on the elastic...

Iron and steel production is an energy-intensive process, often associated with high greenhouse gas (GHG) emissions. There is a drive to reduce GHG emissions in energy-intensive industries. However, the existing technologies used for reducing CO2 emission have reached a plateau. The emergence of novel technologies such as carbon capture, utilisation and storage systems are proposed as a new...

The H2020 project POLYNSPIRE was launched to improve energy and resource efficiency of post-consumer and post-industrial plastic recycling processes, targeting 100% waste streams. Pillars to reach this ambitious goal are: (1) Chemical recycling to recover plastic monomers and valuable fillers, (2) Advanced additivation to enhance recycled plastics quality, (3) Valorization of plastic waste as...

Warm Caliber Rolling (WCR), a thermomechanical operation carried out in the ferritic domain in the range of temperatures 500-700 °C, can lead to a strong grain refinement through mechanisms as dynamic recrystallization or recovery induced by accumulation of strain. Under proper conditions, it is possible to obtain ultrafine grained microstructures, which can significantly improve the...

Dual phase steels are extensively used in automotive safety and structural components because of their low alloying costs, relatively easy processing and optimum combination of strength and ductility. This good combination of properties is attributed to the presence of soft ferrite phase and hard martensite islands in the microstructure. More specifically, the mechanical properties are...

A blast furnace belongs to the most complex and biggest reactors for the treatment of raw materials. One of the most promising approaches to describe numerically the complex process of a blast furnace is a coupled Euler-Lagrange simulation. It combines an accurate representation of the solid phase with its reducing gas formed by oxidation of coke and iron reduction in conjunction with the...

The injection of inert gas in the inflow region of the continuous casting mold is a common measure in continuous casting to reduce clogging. Depending on the gas injection rate, the resulting gas bubbles can significantly influence the turbulent mold flow because of their buoyancy forces. The mold flow pattern can change from double to single roll as a consequence of high gas injection rates...

Quality control for efficient steel processing is extremely important with the need to decarbonise production, produce steels to tighter material property constraints. Thermo-mechanical controlled processing and the models for predicting microstructural development need input from smart sensing technologies to improve their capability, particularly for advanced high strength steel grades...

ABSTRACT
Flow behavior constitutive equations have been widely used in FE analysis and parameter's optimization in thermomechanical processes of micro alloy steels. Flow curves of API-5L X70 pipeline micro alloy steel were analyzed to determine the material genome. Hot compression tests were performed over the different temperatures of 850-1150 °C and the strain rate range of 0.001-1 s^(-1) ...

The lowest part, the hearth, of the blast furnace is the most non-transparent region of the process as no measurements of the internal state are available due to extremely hostile conditions. Since the life of the hearth lining limits the furnace campaign length and the state of the hearth is of significant importance for maintaining an un-disturbed and well-controlled drainage of hot metal...

Nozzle clogging in continuous casting of steel originates by the adherence of alumina particles and other oxides, precipitated during the liquid steel deoxidation, on the refractory material's surface. Hence, these particles' nucleation and growth rates in supersaturated melts are analyzed considering, specifically, the role of the interfacial tensions between alumina, silica, and other oxides...

Fasteners are quite simple products but critical in most sectors. Bolt manufacturing is a large, well-established industry worldwide with a long history however, due to the low value nature of this product type, the production process has not been fully metallurgically optimised, increasing yield and production rates have instead been main areas of improvement. With modern analysis tools and...

The burden materials in the blast furnace are traditionally charged to build distinct layers of ore and coke, which makes it possible to control the conditions in the shaft. Since ore and coke have fundamentally different density, the mass flow rates of solids at different radial locations will vary, which affects the heating of the burden upon its descent. Further, as the materials show...

Clog formation within the submerged entry nozzle is highly detrimental to the fabrication of steel alloys during the continuous casting process. The growth of the clog is self-accelerating and leads to numerous issues in the manufacturing process, including reduced manufacturing speeds, changes to the steel solidification pattern and even the introduction of detached parts of the clog into the...

The internal geometric profile nozzle plays an important role in the obtaining proper flow patterns in the thin slab continues casting funnel mould. After some geometry design concepts are derived, numerical and physical modelling like water modelling is applied to elaborate and verify if the design can meet the expected target. For the numerical simulation, some attentions should be taken to...

In this research, a previously developed hot rolling simulation system, based on novel meshless computing technology, is upgraded from the pure plastic to a more realistic elasto-plastic material model that allows to cope with damage mechanics. This enables a more detailed virtual testing of different rolling schedules. Helmholtz free energy is used to structure damage coupled constitutive...

This contribution presents the large eddy simulation applied to the 2D model of the continuous casting process. The flow of molten steel in the continuous casting process is approximated by an incompressible fluid flow, which is described with transport equations for mass, momentum, spices, and energy, that are closed with fractional step method for pressure-velocity coupling, Boussinesq...

Temperature dependent strain induced precipitation of (Ti,Nb,V)(C,N) MX carbonitrides can retard static recrystallization. Predicting the role of microalloying elements on the recrystallization behavior by thermokinetic simulation is expected to support the technological process optimization and cost reduction of steel development. In this study, we assess the predictive power of...

The design and control of blast furnace (BF) ironmaking must be optimized in order to be competitive and sustainable, particularly under the more and more demanding and tough economic and environmental conditions. To achieve this, it is necessary to understand the complex multiphase flow, heat and mass transfer, and global performance of a BF under different conditions. Mathematical modelling,...

INTECO is a privately owned Austrian engineering and consultancy company founded in 1973 being specialized in metallurgical process technology and the related equipment for melting, refining, casting, atomization and solidification of high-performance steels, superalloys and titanium.
Over the past decades the product portfolio has been consistently grown ranging nowadays from primary...

Identification of the three-dimensional cellular automata (CA) model of static recrystallization (SRX) based on the inverse analysis concept is the primary goal of the research. The developed CA model is a full-field approach that captures local heterogeneities in grain morphology, crystallographic orientation, and distribution of stored energy after deformation. The identification stage is...

Mass transfer between liquid steel and slag is frequently encountered in the steelmaking processes: for composition adjustment such as desulfurization or dephosphorization, but also for lubrication of continuous casting mold, since the slag viscosity has a major effect and is mainly depending on the thermodynamic equilibrium between the phases. To predict the composition of both the slag and...

Continuous casting is nowadays the world leading technology for the steel production. The thin slab casting (TSC) is featured by a slab shape close to the final products, which are casted at a high speed with the fast solidification rate. The quality of the thin slabs strongly depends on the uniformity of the turbulent flow, the super-heat distribution, and the growth of the solidified shell...

The behavior of nonmetallic inclusions (NMs) on gas bubble surfaces has received increasing attention due to its importance in clean steel production. Agglomeration of NMs at the gas/steel interface is usually observed because of capillary attractions. The Kralchevsky–Paunov (K-P) model is often employed to calculate this capillary force quantitatively. In the K-P model calculation,...

The quality of steel produced by a continuous caster depends on the flow condition during initial solidification in the mould. While the understanding of the flow and its effects is highly desirable, high temperature, opaqueness of the liquid steel and harsh conditions during the production limit viable measurement methods. Contactless Inductive Flow Tomography (CIFT) can provide information...

A knowledge driven, physically based and reliable determination of process parameters during hot rolling is crucial for the accurate prediction of final product properties and for the precise layout and design of hot strip mills.
Based on known initial conditions of the material and accurate product tracking, the evolution of physical properties can be calculated based on the time-temperature...

Industry 4.0 promotes the use of digital twins to improve manufacturing efficiency. In this paper we report work being carried out at the NISCO-UK Research Centre at the University of Leicester, UK, looking at steel plates manufacturing. Physics-based models of the production of slabs by continuous casting and subsequent rolling are used to further improve the understanding of the impact of...

During slag granulation, after metal separation in the Blast Furnace Main Trough, the contact between water and slag can lead to explosions, due to presence of pig iron in the slag. Aiming to reduce the molten metal passage through the slag port of a main trough in a Brazilian steel mill, in order to avoid explosions during slag granulation, multiphase numerical simulations were performed for...

An existing and in-use online transient three-dimensional heat transfer model (3DHTM), combined with a solidification and microstructure model (SMM) for the continuous casting of steel are presented. The 3DHTM and SMM are integrated into a single online software entity and this has been installed in the automation systems of four slab casters in Finland. The development of this integrated...

Since its first implementation in the 1950’s thermo-mechanically controlled rolling has proven to be invaluable in steel industry for giving grain size refinement and hence improved strength and toughness. This led to widespread use of lab based thermo-mechanical simulators, such as Gleeble and ServoTest machines, to reproduce the strain, strain rate and temperatures of hot deformation and...

Various quality problems emerging in the final product of the continuous casting of steel can be related to an insufficient control of the steel flow in the mold. To meet the requirements of high-quality products, electromagnetic forces are utilized to control the steel flow, and hence to improve the product quality. The usage of electromagnetic fields gained momentum in recent years due to...

The formation and removal of exogenous inclusions in a real-size two-strand tundish is simulated by the proposed unsteady 3D comprehensive numerical model of the respective fluid-structure interaction, which takes into account the impacting and washing effects on the refractory wear. A large eddy simulation is employed to describe the molten steel vortex flow. Thus, the thermal profiles of the...

Mesh quality is a fundamental issue with the Finite Element Method. Structured meshes are quite common: however, they usually have some problems when it comes to change rapidly the element size in the adaptive mesh. For this reason, to usage of unstructured mesh is more appropriate when the target is the creation of an adaptive mesh using quadrilateral elements. This work aims to present a...

AOD process consists of two main stages: decarburization and reduction of slag. In the decarburization stage, oxygen is injected through nozzles – and also through top lance in combined-blowing vessels – to remove dissolved carbon from the metal bath. The oxygen injection is diluted with nitrogen or argon to avoid excessive oxidation of alloying elements, such as chromium and manganese. After...

Experimental investigations of the fluid flow in a continuous casting mold are performed at the Mini-LIMMCAST facility at HZDR, which is a liquid metal mockup operated with GaInSn at room temperature. Velocity measurements in the non-transparent liquid metal are performed by means of the ultrasound Doppler velocimetry (UDV), which enables the reconstruction of the complex flow pattern in the...

Given the sheer volume of resources and energy used in smelters around the world, the optimization potential of simulation and modeling-based efficiency measures is huge.
However, simulations require representative input data in order to work properly. In other words: simulations can only be as good as the data they are built on. In addition to the detailed model the best possible...

Molten steel is alloyed during tapping from the melting furnace to the argon-bottom stirred ladle. The metallic additions thrown to the ladle during the ladle filling time are at room temperature. The melting rates or kinetics of sinking-metals, like nickel, are simulated through a multiphase Euler-Lagrangian mathematical model during this operation, carrying out a previous assessment of the...

Internal and external defects are recurrent problems during Continuous Casting (CC) of steel due to the introduction of new grades that are often difficult to cast, as well as the everlasting pursuit for higher quality and improved yield.
Numerical modelling was introduced as an alternative to study CC defects in a more cost-efficient way than using traditional trial-error tests in the...

The electric arc furnace (EAF), as one of the most critical equipment in the modern steelmaking process, has gained rapid prominence in the industry over the last decades due to its high efficiency and low emission. Generally, EAF utilizes electrical and chemical energy to achieve the purpose of scrap melting while the heat released by arc plasma is considered as the major input to melt scrap....

Nowadays, the Vacuum Arc Remelting (VAR) process is effectively utilized to manufacture Titanium-based alloys. Most often, an external axial magnetic field (AMF) is deliberately introduced to stabilize the arc. The AMF also impacts the magnetohydrodynamics (MHD) in the melt pool, and consequently the solidification (macrosegregation and grain structure) of the ingot. To study the...

A fluid/fluid mass transfer model implemented in computational fluid dynamics (CFD) is presented. This includes the model description, proving and application for a liquid steel/ slag mass transfer within a purged steel ladle. The model considers the prevailing flow as well as concentration and for the flow it distinguishes between laminar and turbulent flow. For the case of turbulent flow,...

Continuous casting of steel typically consists of primary, secondary, and air-cooling zones, whose intensity is weakened in sequence. It promotes the transition of columnar dendrites to equiaxed ones, especially for middle and high carbon steels. However, due to the weak cooling rate, the inner solidification structure is prone to become coarsened deteriorating the solidification quality. So,...

Bottom blowing, combined with top-blowing, is a widely used approach in the BOS process to enhance the mixing across the phases and reduce the time to decarburize the hot metal. Damages due to scrap loading or blockages by solidified steel or slag could reduce the available number of bottom blowing tuyeres, particularly during the last heats of the campaign. This reduces the mixing efficiency...

The electro-slag remelting (ESR) is a well-known process, which is widely used in the production chain of high-quality alloys. These alloys are used for many different applications ranging from tool steels to superalloys used in aero- or spacecraft applications. The process design is mainly unaltered since several decades. There only have been improvements regarding the process control and the...

Process stability during continuous casting is an essential criterion to produce high-quality slabs. The meniscus is the most sensitive zone of the whole strand, as the initial strand shell is generated there. Unsteady bulging of the strand shell between two rollers is inducing feedback on the mold level position due to the liquid core of the strand. During unsteady bulging, heavy mold level...

Predicting contact conditions between the solidified shell and the mold wall is essential to simulate heat transfer and mold friction in continuous casting due to their significant impact on interfacial resistance and normal stress at the mold-strand gap. However, the multi-physics nature of continuous casting coupling fluid flow, heat transfer, solidification, and thermo-mechanical stresses...

In basic oxygen steelmaking, the metal droplet decarburization plays a major role to determine the residence time and reaction (slag/metal interfacial) area of the droplets due to bloating while reacting in the emulsion zone. This ‘residence time’ and ‘reaction area’ controls the overall refining efficiency in BOF, more importantly dephosphorization efficiency. So, it is important to...

Development of Ultra High Strength Steel (UHSS) is a hot topic in recent years as demand for light weight automobile and machinery steels increases drastically. To understand the inclusion behaviors in a high Ti UHSS grade during casting and slab cooling, automated inclusion analysis tool was utilized to investigate the TiN precipitates distribution and their heterogeneous growth on oxide...

As an essential stage in inclusion removal processes, separation of inclusion at the steel-slag interface certainly affects the overall removal efficiency and is of great importance to molten steel cleanliness. In this study, the dynamics of a spherical Al2O3 inclusion (50 μm in diameter and with a typical contact angle of 45°) interacting with the steel-slag interface is investigated using...

A simple Lagrangean traveling slice model has been successfully used in the past for prediction of the relations between the process parameters and the temperature field in steel continuous casters. Such models are used in basic process parameters optimization with respect to the casting format and steel-grade. It is the purpose of the present paper to include also the concentration,...

As one of the largest production chains in the world, the steel industry faces an ever-increasing demand for higher level of functionality and quality of final products at reduced environmental impact and manufacturing cost. The steel industry has developed an extensive range of sensors to generate data, monitor, and control steelmaking processes. Despite these advances, issues remain in the...

Complex deoxidation by Si and Mn is beneficial for certain steel long products since it leads to the formation of low temperature melting manganese silicates. A better understanding of the mechanisms for inclusion formation in steels deoxidized by these elements need thorough investigation. In this regard, a kinetic model based on diffusion of steel species has been developed for deoxidation...

A three dimensional Computational Fluid Dynamics (CFD) model using an Euler-Lagrangian approach is developed in order to understand the mixing of liquid steel in a ladle using Argon purging plugs in the bottom. The simulations consider liquid steel and slag as continuous liquid phases and Argon is considered as homogenous Lagrangian particles. The interfaces between the steel, slag, and top...

The impact on process performance after changing parameters like burner mass fluxes, dwell time, or gas composition is vital knowledge. It can be obtained by various methods as for example experimental setups, or computational fluids dynamic (CFD) simulation. The disadvantage of those conventional methods is that they are time-consuming and expensive for full-size industrial applications....

Ultra-Low Carbon (ULC) steel grade is used in automotive industry due to the good formability and a superior surface quality. Titanium is usually added to this grade in order to improve physical properties such as total elongation, normal anisotropy, and strain hardening. However, adding Ti increases clogging tendency comparing Ti-free ULC. For clogging in casting of Ti-ULC steel, two key...

In the last decades, steelmaking processes have been a subject to substantial modernization in terms of digitalization and informatization of various plants. Whether in the past operational measurements acquired by SCADAs have been used solely for process monitoring and fault detection, a closer inspection of the gathered data reveals numerous possibilities also for process enhancement and...

Channel segregation is one of the most frequently observed segregation patterns in large steel ingots, electro-slag remelting ingots, and as cast superalloys. These segregation defects are often referred to as ‘A’ segregate or lamellar-structured segregate in large steel ingots and ‘freckles’ in vertically solidified castings such as in the process of directionally solidification of superalloy...

The complexity of a steel plant’s operations can be daunting, as all production steps are partially interdependent and impossible to isolate. Therefore, ever changing markets and product demands make it a challenging endeavor to keep the production at highest efficiency, while staying competitive and complying with current environmental CO2 regulations.
Because of this demanding situation it...

In modern steel productions, the necessity of a more precise knowledge and control of the process became more important in order to improve production performances, to maintain repeatability on the product quality, to support the necessary process flexibility due to frequent changes in production programs. This became more necessary in Feralpi Group for the case of special steel...

Steel recycling in electric arc furnaces (EAFs) is crucial to achieve environmental as well as economic sustainability of the steel industry. Although the EAFs impose a smaller environmental imprint in comparison to basic oxygen furnaces (BOFs), they still represent an energy-intensive process, with numerous possibilities for improvements. Digitalization and informatization of the steelmaking...

This study establishes an Eulerian columnar-equiaxed solidification model to study the solidification structure and macrosegregation in the continuous casting process by coupling fluid flow, macro-scale heat transfer, microstructure, and solute transport. The different phases include the extradendritic melt, the columnar solid dendrite, the interdendritic melt between columnar dendrites, the...

The electric arc furnace (EAF) generates crude metal from virgin materials and recycled scrap.
Meeting the right concentrations of alloying elements in the crude metal (e.g., Cu, Ni) is crucial.
Scrap with higher uncertainty in the concentrations of such alloys is usually cheaper than virgin materials but might threaten product quality.
Using the cheapest input materials while complying...

A novel solution procedure is developed for the phase field-based simulation of dendritic solidification in Fe-C alloys. The adaptive solution procedure is based on the dynamic quadtree domain decomposition which divides the computational domain into quadtree sub-domains of different size. Each quadtree sub-domain has its own distribution of computational nodes in which the meshless radial...

Continuous casting of thin steel slabs is a cutting-edge technology in iron and steel industry. Electromagnetic Braking (EMBr) technique is widely implemented into thin slab casters to reduce defects caused by strong turbulence in the mold. A slab-casting Strand Electromagnetic Stirring (SEMS) system was developed to control heat transfer in the strand. Sophisticated phenomena, including...

The blockage of bottom blowing tuyere(s) has a significant impact on the refining efficiency in the converter steelmaking process. In this paper, the effect of different arrangements of tuyere(s) blockage on the mixing efficiency was investigated in a 100 t converter with six bottom tuyeres. Both hydraulic experiment and numerical simulation were employed and their results agree well in terms...

Steel manufacturing is a long and complicated process involving iron-making, refining, casting, rolling, etc.; the result, hundreds of processing parameters all with a potential influence on the mechanical properties of final product. This complexity results in significant challenges in the correlation of input parameters with output mechanical properties.

In this work, we applied both a...

Ladle furnace (LF) refining is one of the most popular secondary refining processes to produce clean steel and largely takes the responsibility in the whole steelmaking process. The performance of slag dramatically determines the refining efficiency. In order to realize the precise control of the composition content for refining slag to ensure the optimal performance of CaO-SiO2-MgO-Al2O3 slag...

The steelmaking industry plays an important role on the global anthropogenic $CO_2 $ emissions, accounting to 7 % of all global emissions. In addition, this industry also produces many by-products whose direct disposal without a proper treatment represents an environmental hazardous. In recent years, the recycling of these by-products is gaining increased relevance, to achieve a more...

Additive manufacturing by selective laser fusion of powder appears as a promising process to elaborate high performance parts. Numerical simulation is a valuable tool for understanding laser matter interaction as well as the main physical phenomena governing liquid flow and solidification. It allows determining the influence of the different process parameters, and defining appropriate process...

For the steel industry, modelling is an indispensable tool in process and product development. This will be illustrated by some typical examples from across the production chain, showing model development across several length and time scales. Taking industrial scale CFD and FEM approaches as the starting point, further development is in two directions. The first direction is towards...

State-of-the-art automation technology enables digitalization of the continuous casting process that goes far beyond conventional automation of industrial production. Primetals Technologies provides a digital twin that combines an intelligent digital representation of a casting machine as well as the casting process and the slabs, blooms or billets that are produced. It allows metallurgists...

The aim of the Horizon 2020 SPIRE project MORSE (Model-based Optimisation for efficient use of ResourceS and Energy) is to develop model-based, predictive raw material and energy optimisation software tools for a whole process route. This approach is demonstrated in several pilot cases within the steel industry, to improve resource and energy efficiency, as well as product quality. This paper...

A three phase mixed columnar-equiaxed solidification model coupling mold electromagnetic stirring (M-EMS) was used to investigate the initial solidification in the mold region of billet continuous casting (195 mm × 195 mm). This study focuses on the effect of M-EMS on the dissipation of superheat and its further impact on the formation of equiaxed zone. The equiaxed crystals originate from two...

The RH degassing plant is essential for producing ultra-clean steel, but its vacuum-based nature is hiding the process from close scrutiny. Despite recording the many inputs and outputs of process control and measurements surrounding the plant, the use of produced data is comparatively low, and data handling is a challenge, especially considering correlations of process control data with KPIs...

Numerical simulation plays a crucial role in the optimization of the ladle furnace. This work summarizes various works done to optimize flow modeling in the ladle furnace. This starts at the bubble scale with the development of a new measurement method based on machine learning. Then a comprehensive validation database was created on the physical modeling scale and the numerical model was...

The free grain sedimentation is a common transportation phenomenon in molten steel during the continuous casting process and has great effects on the solidification structure and defects of as-cast. Based on our previously proposed multi-scale cellular automaton model (CA-FVM), the free grain sedimentation in the continuously cast billet is numerical simulated and its effects on the...

Metallurgical processes such as the AOD converter generally utilize gas blowing for mixing and refinement of liquid steel. Due to the harsh environment of the complex and opaque system it is common to study the stirring of the process through physical and numerical models. Effective mixing in the bath has an important role for refinement such as decarburization and have been vividly studied...

Iron and steel making requires a wide range of different raw materials significantly influencing process performance which demands a continuous optimisation of process routes also with respect to energy efficiency as well as environmental emissions. Steadily changing raw material prices and qualities, market situations and product variations are challenging integrated steel plant operators in...

Temperature control is crucial in metallurgical processes. The correct temperature regime during slab casting is essential from a high qualitative perspective. Moreover, incidents like casting abortion because of too low temperature or outbreaks have to be avoid for safety reasons as well. After reviewing the state of the art available temperature models the decision was made to develop a...

The market requirements on the production of high surface and internal quality steel products stimulate a deep understanding and systematic control of the steel solidification behaviour during the continuous casting process. Mathematical modelling is a crucial tool for this matter and therefore has been increasingly used for calculation of surface temperatures and shell growth during the...

Producers of stainless steels such as high alloyed duplex steels have shown an increasing interest in alloying with nitrogen. Alloying with nitrogen can replace some of the Nickel used since it affects mechanical strength, corrosion resistance and stabilizes the austenitic phase. Nitrogen is mainly used as a process gas instead of the more expensive argon gas. Depending on the ratio of...

Continuous casting is an important process to transform molten metal into solid. During secondary cooling of steel, arrays of spray nozzles are used to remove heat from the slab letting it solidify. Effective heat removal from the slab without causing slab cracking and deformation is desired. Air-mist spray is one of the promising technologies to achieve high-rate heat transfer due to the...

Primetals Technologies develops a new monitoring tool to evaluate the defect rate of a strand after casting based on its chemical analysis and its casting history. The defect monitor calculates different types of defect indices, for internal defects and for surface defects. All these indices are mathematical models mainly based on thermodynamical properties, like phase fraction, liquidus and...

Thermo-Calc Software is a well-known developer of large CALPHAD-type databases and software for property and phase diagram calculations based on Gibbs energy minimization. A database for oxides, TCOX, has been available since 1992 and development has been greatly accelerated in recenet years placing special emphasis on steel-slag interactions.
Parallel to the database, the Process Metallurgy...

Real time simulation of strand temperatures is a common practice to adopt the cooling nozzle flow rates according to the desired strand surface temperatures. Usually only a smooth strand temperature is simulated by distributing the cooling heat fluxes smoothly over the strand surface. This simplification saves calculation time and is easier to use for control algorithms. In reality, the strand...

In a blast furnace, hot pressurized air is forced into a packed coke bed where it combusts, generating hot reducing gases for liquid iron production. Stable operation of the furnace requires careful balancing of many operational conditions. Blast furnaces are very resource intensive, and any changes in operating conditions can take hours to produce results. Currently, operators generally rely...

Knowing the material properties seamlessly across the full product length is a prerequisite for enhanced product safety. Primetals Technology created a customizable IT solution based on artificial intelligence and machine learning algorithms which calculates the mechanical properties of a hot rolled or annealed or galvanized steel strip just in time and almost without additional equipment. ...

Microstructural banding is observed as alternating microstructures in cast steel products, parallel to cast/rolling direction. Banding, causing hardenability issues and anisotropy of mechanical properties, is considered to originate from the interdenritic segregation during the solidification of steel. In this study, a three-dimensional heat transfer model (3DHTM) was used to simulate the...

Regardless of the process (continuous casting, ingot or investment casting), the resolution of the thermal equations in FEM software remains a key point in order to have an accurate prediction. This aspect can be relatively complex when heat transfers are dealing with radiative phenomena. The aim of this paper is to describe these major phenomena which take place during the transport of large...

Configuring rules for automated quality evaluation within a quality management system is a complex task, especially when several processing lines along the production route are involved. In fact, the system user needs to transfer process and product knowledge of quality engineers and steel developers into the system in order to enable an automated quality decision that reflects the experts’...

Advanced high strength steel (AHSS) strip used in the yellow goods sector needs a balance of high strength with good toughness and bendability. Cracking during bending can result in failure depending on radius to thickness ratio, in view of the relative low ductility and complex microstructure of these steels. This paper examines how local compositional inhomogeneity can affect bending...