scholarly journals Effect of Temperature Fields Heterogeneity in the Tundish on Primary Structure of Continuously Cast Ingots

2015 ◽  
Vol 60 (1) ◽  
pp. 227-233
Author(s):  
J. Pieprzyca ◽  
Z. Kudliński ◽  
T. Merder
Keyword(s):  
Liquid Steel ◽  
Primary Structure ◽  
Plug Flow ◽  
Temperature Fields ◽  
Effect Of Temperature ◽  
Laboratory Research ◽  
Solidification Velocity ◽  
Cooling Zone ◽  
Working Space ◽  
Steel Flow

AbstractThe formation of the cast strands’ primary structure is a very complex process in terms of the thermodynamics and physicochemical. It occurs during solidification and crystallization of the liquid steel in the crystallizer and in the secondary cooling zone of the CC device. On the basis of the experience gained in the industry and knowledge arising from theory of metals and alloys solidification it can be concluded, that substantial influence on the shape of cast strands primary structure have the temperature of overheating of the liquid steel above liquidus temperature and solidification velocity. A proper control of those casting parameters allows to obtain the cast strands with desired primary structure. In the one and two-way symmetric devices regulation like this is not problematic, in the multi-way devices - specially in the asymmetric - causes a series of problems. In those devices can occur a major temperature difference in each outlet zone of the tundish working space caused by i.e. the distance length diversity of liquid steel stream from the inlet to each outlet and by disadvantageous layout of liquid steel flow zones (turbulent flow zone, plug flow and dead zones) in working area of tundish. Particularly high values of those diversity can be expected in the asymmetric tundishes.The article presents results of laboratory research - model and industrial regarding impact of the liquid steel overheating temperature, but also heterogeneity of the temperature fields in the tundish on primary structure of the cast strands.

scholarly journals Evolution of the Numerical Model Describing the Distribution of Non-Metallic Inclusions in the Tundish

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2229
Author(s):  
Tomasz Merder ◽  
Jacek Pieprzyca ◽  
Marek Warzecha ◽  
Piotr Warzecha ◽  
Artur Hutny
Keyword(s):  
Numerical Model ◽  
Liquid Steel ◽  
Nonmetallic Inclusions ◽  
Steel Production ◽  
Cfd Modeling ◽  
Water Model ◽  
Working Space ◽  
Production Stages ◽  
Steel Flow ◽  
Flow Controllers

Continuous casting is one of the steel production stages, during which the improvement in the metallurgical purity of steel can be additionally affected by removing nonmetallic inclusions (NMIs). This can be achieved by means of various types of flow controllers, installed in the working space of the tundish. The change in the steel flow structure, caused by those flow controllers, should lead to an intensification of NMIs removal from the liquid metal to the slag. Therefore, it is crucial to understand the behavior of nonmetallic inclusions during the flow of liquid steel through the tundish, and particularly during their distribution. The presented paper reports the results of the modeling studies of NMI distribution in liquid steel, flowing through the tundish. CFD modeling methods—using different models and computation variants—were employed in the study. The obtained CFD results were compared with the results of laboratory tests (using a tundish water model). The results of the performed investigations allow us to compare both methods of modeling; the investigated phenomena were microparticle distribution and mass microparticle concentration in the model fluid. The validation of the CFD results verified the analyzed computation variants. The aim of the research was to determine which numerical model is the best for describing the studied phenomenon. This will be used as the first phase of a larger research program which will provide for a comprehensive study of the distribution of NMIs flowing through tundish steel.

scholarly journals Numerical Modelling of Fluid Flow and Thermal Phenomena in the Tundish of CSC Machine

2014 ◽  
Vol 14 (1) ◽  
pp. 103-106 ◽  
Author(s):  
L. Sowa
Keyword(s):  
Numerical Simulation ◽  
Flow Control ◽  
Liquid Steel ◽  
Metal Flow ◽  
Temperature Fields ◽  
Cast Slab ◽  
Flow Control Devices ◽  
Steel Cast ◽  
Control Devices ◽  
Steel Flow

Abstract The mathematical and numerical simulation model of the liquid steel flow in a tundish is presented in this paper. The problem was treated as a complex and solved by the finite element method. The single-strand slab tundish is used to continuous casting slabs. The internal work space of the tundish was modified by the following flow control devices. The first device was a striker pad situated in the pouring tundish zone. The second device was a baffle with three holes and the third device was a baffle without hole. The main purpose of using these devices was to cause a quiet liquid mixing as well as give directional metal flow upwards which facilitated inclusion floatation. The interaction of flow control devices on hydrodynamic conditions was received from numerical simulation. As a result of the computations carried out, the liquid steel flow and steel temperature fields were obtained. The influence of the tundish modification on velocity fields in the liquid phase of steel was estimated, because these have an essential influence on high quality of a continuous steel cast slab.

Numerical Simulation of Behaviour a Non-Metallic Inclusions in an One-Strand Slab Tundish with Steel Flow Controll Devices

2011 ◽  
Vol 56 (3) ◽  
pp. 611-618 ◽  
Author(s):  
A. Cwudziński
Keyword(s):  
Numerical Simulation ◽  
Liquid Steel ◽  
Flow Reactor ◽  
Control Device ◽  
Discrete Phase Model ◽  
Internal Working ◽  
Working Space ◽  
Metallic Inclusions ◽  
Discrete Phase ◽  
Steel Flow

Numerical Simulation of Behaviour a Non-Metallic Inclusions in an One-Strand Slab Tundish with Steel Flow Controll DevicesAn effective refining of liquid steel can be carried out either in a tundish or in the mould of a CSC machine. Being a flow reactor, the tundish performs the function of a link between the steelmaking ladle and the mould. Owing to this fact, the liquid steel resides in the tundish for a specific time, which enables the tundish to be used for refining purposes. For modification oftundish internal working space, two types of flow control device (FCD), namely a ceramic gas-permeable barrier and a subflux turbulence controller (STC), were proposed. For simulation of movement of gas phase and non-metallic inclusions, a discrete phase model was used. The obtained results unambiguously indicate which of the proposed tundish equipment configurations will be more advantageous for intensifying the process of liquid steel refining from NMIs.

Numerical Simulation of the Molten Steel Flow in the Tundish of CSC Machine / Symulacja Numeryczna Przepływu Ciekłej Stali W Kadzi Pośredniej Urządzenia COS

2012 ◽  
Vol 57 (4) ◽  
pp. 1163-1169 ◽  
Author(s):  
L. Sowa ◽  
A. Bokota
Keyword(s):  
Numerical Simulation ◽  
Flow Control ◽  
Liquid Steel ◽  
Metal Flow ◽  
Velocity Fields ◽  
Temperature Fields ◽  
Cast Slab ◽  
Flow Control Devices ◽  
Control Devices ◽  
Steel Flow

The mathematical and numerical simulation model of the liquid steel flow in a tundish is presented in this paper. The problem was treated as a complex one. The velocity fields are obtained by solving the momentum equations and the continuity equation, whereas the thermal fields are calculated by solving the conduction equation with the convection term. One takes into consideration in the mathematical model the changes of thermophysical parameters depending on the temperature. The problem was solved by the finite element method. The one-strand slab tundish is used to casting slabs. The internal work space of the tundish was modified by flow control devices. The first device was a striker pad situated in the pouring tundish zone. The second device was a baffle with three holes. The main purpose of using these was to put barriers in the steel flow path as well as give directional metal flow upwards which facilitated inclusion floatation. The visualization of interaction of flow control devices on hydrodynamic conditions was received from numerical simulations. As a result of the computations carried out, the liquid steel flow and steel temperature fields were obtained. The influences of the tundish modifications on the velocity fields in liquid phase of the steel were estimated, because these have essential an influence on high-quality of a continuous steel cast slab.

scholarly journals Chemical Homogenization Of Liquid Steel Flowed Through Continuous Casting Slab Tundish During Alloying Process

2015 ◽  
Vol 60 (2) ◽  
pp. 561-565
Author(s):  
A. Cwudziński
Keyword(s):  
Liquid Steel ◽  
Mixing Time ◽  
Virtual Model ◽  
Ansys Fluent ◽  
Working Space ◽  
Continuous Casting Slab ◽  
Alloy Addition ◽  
Steel Flow ◽  
Mixing Curves ◽  
Metallurgical Processes

AbstractThis paper presents the results of research on the behaviour of an alloy addition in steel flowing through the tundish used for casting slabs. The device under examination is a wedge-shaped single-nozzle tundish of a capacity of 30 Mg. Due to the complexity of alloy addition dissolution and dispersion in metallurgical processes, a decision was made to use the Species Model available within the Ansys-Fluent®program. For describing the turbulence, the Realizable k-ɛmodel was chosen. By defining the heat losses on respective planes making up the virtual model, the non-isothermal conditions existing during the flow of liquid steel through the tundish were considered. From the performed numerical simulations, the fields of steel flow and steel temperature and alloy addition concentration in the tundish working space were obtained. In order to accurately illustrate the process of chemical homogenization in the tundish working space, mixing curves were recorded. Based on the obtained results (mixing curves), the mixing time needed for achieving the 95% level of chemical homogenization was calculated.

scholarly journals Influence of Hydrodynamic Structure on Mixing Time of Alloy Additions with Liquid Steel in One Strand Tundish

2016 ◽  
Vol 61 (1) ◽  
pp. 295-300 ◽  
Author(s):  
A. Cwudziński
Keyword(s):  
Liquid Steel ◽  
Mixing Time ◽  
Hydrodynamic Conditions ◽  
Step Method ◽  
Ansys Fluent ◽  
Working Space ◽  
Alloy Addition ◽  
Steel Flow ◽  
Mixing Curves ◽  
Active Flow

The knowledge of the hydrodynamic pattern aids in designing new and modernizing existing tundishes. The device under examination is an one-strand tundish of a capacity of 30 Mg. Computer simulation of the liquid steel flow, tracer and alloy addition behaviour in turbulent motion conditions was done using the Ansys-Fluent®computer program. The hydrodynamic conditions of steel flow were determined based on the distribution of the characteristics of tundish liquid steel residence time distribution (RTD). The alloy addition was introduced to the liquid steel by the pulse-step method. Based on computer simulations carried out, steel flow fields and RTD and mixing curves were obtained, and the shares of stagnant volume flow and active flow and the mixing time were computed. Dispersion of the alloy addition in liquid steel during its flow through the tundish is a dynamic process which is determined by the hydrodynamic conditions occurring in the tundish working space.

scholarly journals Numerical Prediction of Hydrodynamic Conditions in one Strand Tundish. Influence of Thermal Conditions and Casting Speed/ Numeryczna Prognoza Warunków Hydrodynamicznych W Jednozyłowej Kadzi Posredniej. Wpływ Warunków Cieplnych I Predkosci Odlewania

2014 ◽  
Vol 59 (4) ◽  
pp. 1249-1256
Author(s):  
A. Cwudzinski
Keyword(s):  
Computer Simulations ◽  
Casting Speed ◽  
Liquid Steel ◽  
Thermal Conditions ◽  
Hydrodynamic Conditions ◽  
Ansys Fluent ◽  
Working Space ◽  
Flow Control Devices ◽  
Pattern Forming ◽  
Steel Flow

Abstract This paper reports the results of computer simulations of the flow of liquid steel in a single-nozzle tundish, which describe the flow hydrodynamics, depending on the thermal conditions and casting speed. In this paper, five casting speeds, namely 0.3, 0.6, 0.9, 1.2 and 1.5 m/min., have been examined. In view of the fact that tundishes are being equipped with various flow control devices and the process of creating specific hydrodynamic conditions is influenced also by the temperature gradient, computer simulations of liquid steel flow under isothermal and non-isothermal conditions were performed. Computer simulations of liquid steel flow were performed using the commercial program Ansys-Fluent ®. In order to explain the phenomena occurring in the tundish working space, the buoyancy number (Bu) has been calculated. The next research step in the analysis of the flow pattern forming in different casting conditions was to record the E and F-type RTD characteristics and to describe the pattern of flow.

scholarly journals Numerical Analysis of the Influence of the Modification of the Ladle Shroud on Fluid Flow Behavior in a One-strand Tundish during Continuous Steel Casting

2021 ◽  
Vol 5 (4) ◽  
pp. 75-83
Author(s):  
Hanna Suchan ◽  
Adam Cwudziński
Keyword(s):  
Liquid Steel ◽  
Steel Casting ◽  
Flow Behavior ◽  
Plug Flow ◽  
Continuous Steel Casting ◽  
Continuous Steel ◽  
Process Modification ◽  
Ideal Mixing ◽  
Steel Flow ◽  
The Impact

A tundish is a device from which liquid steel is pour into a mold. Therefore tundish hydrodynamic conditions have a significant impact on solidification during continuous steel casting (CSC) process. Modification of ladle shroud workspace, allows for the modification of liquid steel movement in the tundish. In the following work, numerical simulations were performed which allowed the impact of the modification of the ladle shroud workspace on the liquid steel flow structure in a one-strand tundish to be determined. In order to assess the impact of the modification of the ladle shroud on the behavior of the liquid steel in the tundish, simulations were performed, on the basis of which the percentage share of stagnant, ideal mixing and plug flow zones were determined. In addition, the mixing parameters were determined, allowing the estimation of casting duration during sequential casting. The flow fields of liquid steel for each modification of the ladle shroud were performed. The average velocity of liquid steel flowing through the tundish, the Reynolds number and turbulent intensity were also described. The obtained results showed, among others, that the application of three cylinders with a diameter of 0.041 m into the ladle shroud with a diameter of 0.11 m increases the share of active flow in the tundish in relation to the tundish with Conventional Ladle Shroud. At the same time, applying a ladle shroud with a diameter of 0.11 m during casting is the most favorable in relation to the hydrodynamics of the tundish.

scholarly journals New Insight on Liquid Steel Microalloying by Pulse-Step Method in Two-Strand Slab Tundish by Numerical Simulations

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 448
Author(s):  
Adam Cwudziński
Keyword(s):  
Liquid Steel ◽  
Mixing Time ◽  
Casting Process ◽  
Step Method ◽  
Flow Control Devices ◽  
Alloy Addition ◽  
Interesting Approach ◽  
Control Devices ◽  
Steel Flow ◽  
Alloy Concentration

Developing a technology for introducing alloy addition to liquid steel during the course of continuous casting process seems to be an interesting approach to enhancing the steelmaking process, especially as the effective introduction of micro-additives or non-metallic inclusion modifiers to the liquid steel is the key to the production of the highest-quality steel. This paper presents the results of investigation describing the process of liquid steel chemical homogenisation in the two-strand slab tundish. The alloy was fed to liquid steel by pulse-step method. Five tundish equipment variants with different flow control devices and alloy addition feeding positions were considered. The paper includes fields of liquid steel flow, alloy concentration vs. time curves, dimensionless mixing time, minimum time values and alloy concentration deviations at tundish outlets. The results pointed much more effectively with liquid steel mixing nickel than aluminium. For aluminium obtaining a 95% chemical homogenisation level requires three-fold more time. Moreover, it is definitely beneficial for chemical homogenisation to initiate the alloying process simultaneously in two sites. This procedure generates, among others, the least alloy deviation of concentration at tundish outlets.

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