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CHAIR OF SIMULATION AND MODELING METALLURGICAL PROCESSES

Onging Research Projects

Topic: "Inverse process chain simulation for Al-castings"

Applicant: Prof. A. Ludwig
Scientist:
T. Holzmann

Foundation: FFG-COMET: K2-MPPE
Partner: MCL

Starting date: 01.04.2014
Termination date: 31.12.2017

Abstract:
Ziel dieses Projekt ist es, durch inverse Prozesskettensimulation die methodische Grundlage zur computerunterstützten Optimierung einer robusten, flexiblen und ressourcenschonenden Produktion zu schaffen. Im Rahmen dieses Projekts wird eine Prozesskette aus Gießen-Lösungsglühen-Abschrecken-Auslagern für eine aushärtbare Al-Gusslegierung mit dem Ziel der optimierten Einstellung von lokalen Eigenschaften durch gezielte lokale thermische Behandlung in kritischen Gussteilbereichen betrachtet.

Publications: B20, C159


Topic: "Modelling of solidification during hot dip galvanizing"

Applicant: Prof. A. Ludwig
Scientist:
Dr. J. Mogeritsch

Foundation: FFG-COMET: K2-MPPE
Partner: Voestalpine, MCL

Starting date: 01.10.2013
Termination date: 30.09.2017

Abstract:
Die zentrale Zielsetzung von Moduls 4 ist die numerische Beschreibung des Erstarrungsvorganges bei der Beschichtung von Stahlbändern mit unterschiedlichen Zn-Al-Mg Legierungen im produzierenden Umfeld. Basis hierfür bilden Grundlagenuntersuchungen mittels eines Schmelztauchsimulators mit dem Schichten unter definierten Bedingungen hergestellt werden können. Diese Untersuchungen werden zur „Kalibrierung“ eines 3D Phasenfeldansatzes zur Mikrostrukturvorhersage herangezogen, so dass u.a. thermodynamische Inputdaten einer eingehenden Verifikation unterzogen werden. Die Umsetzung der Ergebnisse auf die Gegebenheiten bei der Produktion erfolgt dann zunächst rein thermisch um Wärmeflüsse im Kühlturm entsprechend abzuschätzen. Mit diesen Informationen als Randbedingungen, und basierend auf den Ergebnissen des Schmelztauchsimulators, wird dann die Erstarrung bzw. die Mikrostrukturentstehung der Zn-Al-Mg Beschichtung im produzierenden Umfeld simuliert. Nach Verifikation der numerischen Vorhersagen durch Vergleich mit den tatsächlich auftretenden Mikrostrukturen wird dann das neue numerische Tool eingesetzt um das Gefüge, und damit letztlich die Eigenschaften der Schichten zu optimieren.

Publications: C155


Topic: "Reduced build-up growth during hot-dip galvanizing"

Applicant: Prof. A. Ludwig
Scientist: M. Stefan-Kharicha

Foundation: FFG-COMET: K2-MPPE
Partner: Zink-Association, MCL

Starting date: 01.04.2016
Termination date: 31.12.2019

Abstract:
The objective of the project is to reduce build-up growth on zinc bath hardware during hot-dip galvanizing to improve line quality and productivity. The main goal is to investigate the growth mechanism and to identify the main growth driving factors to determine conditions for controlling and reducing the build-up growth. The methodological approach is to further improve and refine the sharp interface solidification model, developed at MUL-SMMP, for any faceted crystal morphology. This model will be able to predict crystal shape and growth on hardware surfaces and crystal shape and growth of picked up dross particles depending of the local conditions of flow, flow direction, pressure, temperature, Zn-Al-Fe concentrations and conditions around dross particles near the laminar flow boundary layer of the bath surfaces. Detailed near surface multiphysical and scale resolving turbulence simulations will be performed to obtain these local conditions on parts of the static and moving bath hardware surfaces. Realistic boundary conditions for the detailed multiphysical simulations will be extracted from galvanizing bath model results established at MCL. The findings will help to identify reasons of large and small dross accretion on moving and stationary bath hardware and relate them to the local conditions. From this, strategies can be defined to reduce build-up growth on the bath hardware.

Publications:


Topic: "Combined modelling of solidification and mush visco-plasticity"

Applicant: Prof. A. Ludwig
Scientist:
Dr. C. Rodrigues

Foundation: FWF
Partner: -

Starting date: 01.05.2016
Termination date: 30.04.2019

Abstract:
During solidification of alloys equiaxed grains form, grow and move. Small grains are carried with the melt flow, while with further growth grains often sink down and sediment. At a certain dense packing, they form a coherent network with intergranular/interdendritic liquid. Such a semi-solid slurry is known to have visco-plastic flow behavior. In addition, thermal contraction leads to a deformation of the solidifying part. In order to describe these phenomena it is suggested to combined three simulation approaches in the present project proposal: (i) a modeling approach which describes growth and sedimentation of crystals, (ii) a modeling approach which describes the mechanical behavior of the sedimented layer (visco-plasticity) and (iii) a modeling approach to describe the thermal contraction of the cast part. Recent development describe the combined modelling of fluid/gas flow and deformation of solids (FSI: fluid-structure interaction), e.g. gas flow in exhaust pipes). The present project proposal targets at an even more complicated case namely the combination of flow with deformations in a solid not via a given surface (as in FSI) but through an a priory unknown volume, the two phase mushy zone.

Publications: J124, C145


 

Topic: "Ultrafast simulations of metallurgical processes on modern graphic cards"

Applicant: Prof. A. Ludwig
Scientist: -

Foundation: FFG: BRIDGE early
Partner: RHI

Starting date: 01.04.2015
Termination date: 31.03.2018

Abstract:
During the course of the FFG ModSim project SimProCUDA, which terminates in October 2014, the scientific project partner of this early bridge project, MUL, has developed a Smoothed-Particle Hydrodynamics (SPH) code on modern Graphic cards (GPU's). This development is supposed to simulated metallurgical processes like tundish flow or flow in the mould region of a continuous casting with a remarkable shorter computation time compared to classical CPU-based codes. Although, the development of such a tool is a very challenging task, the preliminary results gained so far were such that one of the companies from the advisory board of SimProCUDA, the RHI AG, is willing to bring MUL's basic research efforts on SPH simulations closer to a potential commercialisation. However, this needs further efforts with respect to new/improved developments of the SPH formalism in order to realistically model (i) turbulence, (ii) gas loaded flows, (iii) electrodynamics and magnetohydrodynamics and (iv) solidification. So further developments on these topics are the scientific objectives of the present early Bridge project. It is planned that the achieved results will be validated against experiments performed by the company partner and against classical CPU-based simulations. However, it is not only the accuracy we are targeting on, but also the computation time. Here, we expect a speedup of 50-100 compared to classical simulation tools. We intend to install a beta-version of the SPH developments with a corresponding Graphical User Interface on a GPU based simulation platform that will be purchased by the company partner. Computing on Graphic card is a strategic topic that cannot be neglected if we want to stay at leader position in the field of metallurgical process simulations. It is expected that other concurrent groups in the word, especially in Asia, will soon launch their first metallurgical process simulation on GPU's. Therefore, high priority must be given to the development of process simulations with GPU technology for the next years.

Publications:


Topic: "On the formation of macrosegregation during vertical continuous casting of large round steel rods"

Applicant: Prof. M. Wu
Scientist: Y. Zheng

Foundation: FFG: BRIDGE early
Partner: Primetals Technology Austria GmbH

Starting date: 01.06.2014  
Termination date: 31.05.2018  

Abstract:
Recently, an innovative continuous casting technique was proposed for producing large steel rounds by industry. However, we know that the intensity of macrosegregation typically increases with the size. Therefore, a numerical method is used to analyze the macrosegregation mechanisms during casting and solidification of the large vertically-cast rounds. A three-phase mixed columnar-equiaxed solidification model is used. This model, as originally developed for large ingot castings, is to be further extended (adapted) for following new functionalities: (i) large vertical continuous casting; (ii) effect of electromagnetic stirring; (iii) origin of equiaxed crystals by electromagnetic stirring. The model with new features is subject to evaluation against experiments.

Publications: J132, J130, C153, C148


Topic: "Slags, refractories and inclusions in the cc process"

Applicant: Prof. M. Wu
Scientist: H. Barati

Foundation: FFG-COMET: K1-Met
Partner:
Montanuniversitaet Leoben, RHI AG, voestalpine Stahl GmbH, voestalpine Stahl Donawitz GmbH

Starting date: 01.07.2015  
Termination date: 31.12.2018 

Abstract:
Strategical goal of the project “Slags, refractories and inclusions in the cc process” is to achieve high quality “clean steel” through the control of reactions/interactions of the liquid steel with other contacting materials like slags, refractories and inclusions. One work package of this project (WP 5) is the “understanding the clogging mechanism in the SEN boundary layer through numerical modelling at the microscopic scale”. This WP is to use a numerical approach to study the clogging phenomenon during continuous casting.

Publications: C152


Topic: "Investigation of the effect of Ti on clogging of feeding systems and its prevention for continuous slab casting"

Applicant: Prof. M. Wu
Scientist:
H. Barati

Foundation:  EU-RFCS
Partner:
VDEh-Betriebsforschungsinstitut GmbH (Germany), Montanuniversitaet Leoben (Austria), Voestalpine Stahl GmbH (Austria), Comdicast AB (Sweden), Salzgitter Flachstahl GmbH (Germany).

Starting date: 01.07.2014  
Termination date: 31.12.2017 

Abstract:
The reduction/prevention of clogging during continuous casting of Ti-stabilised ULC steel grades has a decisive influence on product quality and yield. There is still a lack of complete understanding of this phenomenon although many investigations were performed at European and International level. The strategical goal of this European project is to gain a better understanding of the mechanisms contributing to clogging and exploitation of this knowledge leading to process and constructive optimization measures. Both experimental (at the laboratory pilot scale and at the industry scale) and numerical investigations will be carried out. In the sub-project (Montanuniversitaet Leoben), a new numerical model for clogging is to be developed by considering: (i) transport of non-metallic inclusions; (ii) buildup of the clog in the submerged entry nozzle; (iii) growth of the clog and interaction with the turbulent flow.

Publications:


Topic: "Metastable solidification of novel peritectic structures – studies with transparent model alloys: ISS GO" (METTRANS ISS-GO)

Applicant: Prof. A. Ludwig
Scientist: Dr. J. Mogeritsch

Foundation: FFG-ASAP
Partners:
DLR Cologne, EPFL Lausanne,

Starting date: 01.11.2013
Termination date: 30.04.2017

Abstract:
The present project proposal METTRANS-ISS GO complements the ongoing ESA-MAP project METCOMP and the corresponding ESA flight hardware project TRANSPARENT ALLOYS. It deals with the influence of solutal convection on layered peritectic solidification structures and the dynamic of solid/liquid interface morphologies close to the limit of constitutional undercooling. The investigations are carried out as direct solidification experiments in a micro Bridgman-furnace using the transparent organic model system TRIS-NPG which solidifies metal-like. METTRANS-ISS GO includes experimental investigation on earth at the University of Leoben and at ESA, and the final execution of space experiments aboard of the ISS. The results are the basis for a fundamental understanding of peritectic pattern formation and its dependence on solutal convection and thus may serve to produce innovative alloys with a particular microstructure.

Publications: J111, J95, B16, C142, C115, C106


Topic: "Metastable Solidification of Composites: Novel Peritectic Structures and In-Situ Composites” (METCOMP)

Applicant: Prof. A. Ludwig
Scientist: Dr. J. Mogeritsch

Foundation: ESA
Partners: DLR Cologne, EPFL Lausanne, Wigner Research Centre for Physics Budapest, Schwermetall Halbzeugwerk GmbH & Co. KG Stolberg, Thyssen Krupp Stahl AG Duisburg, Wieland-Werke AG Ulm

Starting date: 01.09.2016
Termination date: 31.08.2019  

Abstract:
The project “Metastable Solidification of Composites: Novel Peritectic Structures and In-Situ Composites” (METCOMP) was established by ESA in 2000. The intention of the project is solidification of materials into a composite structure. Composite materials are of high interest since they combine advantageous properties of different phases within one material. In combination with ceramic particles make them applicable at high temperatures. Several aspects of the topics are investigated by different scientific teams in Swiss, Hungary, Germany, and Austria. EPFL had focused on the peritectic system Cu-Sn with solidification at low growth rate and has now an advisory function. DLR investigates composite materials consisting of a metallic matrix and ceramic particles, which can be used as high temperature materials. The partner in Budapest developed a phase-field model to describe added particles within the melt. MUL investigates the organic peritectic model system TRIS-NPG, which is optically transparent and allows the direct observation of the dynamic of peritectic growth under similar growth conditions as used for Cu-Sn. Additionally, tracers are used as added particles like ceramic and to display the fluid flow ahead of the solidification front.

Publications: J111, J95, B16, C142, C115, C106