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

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...

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...

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...

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...

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 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...

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...

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...

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...

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...

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,...

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...

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...

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,...

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...

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...

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...

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 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...

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...

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...

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...

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...