bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of bath smelting processes for producing iron
Authors: Fruehan Richard J. , Ito K. , Ozturk B. 
Published: December 2016

A simulation model on bath smelting processes for the production of iron was developed which predicts the coal, flux, ore, and oxygen consumptions and the off gas volume, temperature and composition. The model is comprehensive in that it takes into account all of the important variables including coal composition, metal composition, ore composition, slag basicity, post combustion ratio, (PCR), prereduction degree (PRD), heat transfer coefficient (HTC), flux, scrap charge, and heat losses. Four basic cases were considered: I. 30% PRD–50% PCR; II. 90% PRD–0% PCR; III. 60% PRD–30% PCR; and IV. 0% PRD–50% PCR. Several different coals were considered and a sensitivity analysis of the critical variables was performed. The model also estimates the sulfur content of the metal. The major conclusions are:Post combustion siginificantly reduces coal consumption but above 20% PCR little reduction of FeO to Fe can be performed with the off gas.Prereducing to FeO (case I) and having as much post combustion as consistent with good heat transfer is an attractive process.This process only requires a simple prereducer, uses less coal, and is relatively insensitive to the type of coal used.High off‐gas temperatures may pose a potential problem. The off‐gas temperature can be reduced by using an O2–air mixture for post combustion, limiting post combustion or adding water to the gas.The use of CaCO3 in place of CaO or of supplemental electricity does not appear attractive.The melting unit is theoretically an energy efficient scrap melter. For case I using 200 kg of scrap as part of the charge the coal consumption decreases by about 80 kg.With PCR > 30% the FeO content of the slag is expected to be 2–5%, and the metal will not be saturated with carbon. These factors and the increased sulfur load since coal is the fuel indicate the sulfur content of the metal may exceed 0.25%.
Fluidized bed reduction as the prestep of smelting reduction
Authors: Gudenau Heinrich Wilhelm , Fang Jue , Hirata Takejuki , Gebel Ulf 
Published: December 2016

Comparing the four fundamental ironmaking processes the reasons for the development of smelting reduction were derived. Based on bibliographical references a fundamental classification of the main important smelting reduction processes is presented regarding the process engineering principle of both steps, prereduction and final reduction. According to fundamental considerations, the fluidized bed process seems to be optimal for prereduction.Experiments to investigate the influence of process parameters on sticking – the main problem of fluidized‐bed reduction – and their interactions were carried out. Optimal operating conditions to run a fluidized bed as the prereduction unit of smelting reduction process were derived.A special “Reduction‐SEM” to directly observe metallurgical reactions, like the precipitation behaviour of iron during iron ore reduction, is presented. With the results of such investigations it is possible to show the influence of precipitation behaviour on sticking and to assign the different types of precipitates to the Baur‐Glaessner‐Diagram. The influence of hydrogen addition on surface morphology is sketched out.
Kohlenstoffpräzisionsmessung mittels Sublanze – Ermittlung der Meßstrategie
Authors: Wagenleithner Peter , Aberl Heinrich 
Published: December 2016

Die Konstruktion eines präzisen Meßgerätes zur Temperaturmessung von erstarrenden Fe–C‐Proben erforderte ein Überdenken der Auswertemethode bezüglich des Haltepunktes der Erstarrung. Die Bestimmungsgenauigkeit muß in der Größenordnung der elektrischen Temperaturmessung liegen. Eine numerische Analyse zeigt, daß im theoretischen Verlauf der gesuchte Punkt durch ein einfaches numerisches Kriterium angegeben werden kann. Für reale Messungen muß darüber hinaus eine Auswertemethode bezüglich Unterkühlung, Kurveneinbrüchen, etc. angewendet werden.Das Ergebnis weist eine statistische Genauigkeit von ca. 1,4°C bezogen auf die Sollhaltepunkttemperatur auf, was in Anbetracht der bei Thermoelementen garantierten Genauigkeit von ca. ± 1°C als sehr gut bezeichnet werden muß, enthält es doch auch alle elektrischen Fehler des Gerätes.
Oxygen activities in Cr‐containing Fe and Ni‐based melts
Authors: Heinz Michael , Koch Klaus , Janke Dieter 
Published: December 2016

Plug‐type, ZrO2‐based oxygen sensors have been used for long‐term measurements of oxygen activity in Fe–O–Cr and Ni–O–Cr melts. In these melts, equilibrated with chromium oxide, oxygen activities aO were determined as a function of Cr content. From the experimental results, data were derived for activity coefficients fO and of 1st and 2nd order interaction parameters eOCr and rOCr.Cr2O3 has been identified as the oxide phase in equilibrium with the metal melt at ≥ 5 wt.% Cr in the case of iron and at ≥ 0.2 wt.% Cr in the case of nickel. Oxygen activities and oxygen contents in Cr‐containing iron melts are lowered with increasing additions of nickel. Further investigations were directed to aO determination in Fe–O–Cr–C and Fe–O–Cr–Al melts.
Optimierung der Durchmischung in diskontinuierlichen und kontinuierlichen Aufblasreaktoren für die Entkohlung von Fe–C‐Schmelzen mit Sauerstoff
Authors: Wulfmeier Ekkehard , Koch Klaus 
Published: December 2016

Bei der schlackenfreien bzw. schlackenarmen Brennfleckentkohlung werden in der betrieblichen Praxis nicht die kinetisch möglichen hohen Entkohlungsgeschwindigkeiten erreicht. Modellversuche bei diskontinuierlicher und kontinuierlicher Betriebsweise sollen Möglichkeiten aufzeigen, wie durch richtige Wahl des Reaktortyps und der Prozeßparameter das Strömungsund Durchmischungsprofil im Reaktorbad zu optimieren ist. Wasser‐Luft‐Modellversuche wurden in den Reaktortypen Einzelrührkessel, Rührkesselkaskade und Rinne durchgeführt. Zur Unterstützung der schlackenfreien Entkohlungsreaktion muß der Strömungsverlauf innerhalb des Reaktorbades bei kontinuierlicher Arbeitsweise in verschiedenen Richtungen unterschiedlichen Anforderungen genügen. In Längsrichtung sind geringe Rückvermischungen mit einheitlichen Aufenthaltszeiten zur Erstellung eines homogenen Frischproduktes gefordert. In den Reaktorquerrichtungen soll die Durchmischung demgegenüber hoch sein, um einen hohen Stofftransport an den Reaktionsort Brennfleck zu sichern.Das Ziel gleichmäßiger Verweilzeiten in axialer Richtung wird am besten durch den Reaktortyp „Kaskade“ mit einer Stufenzahl von mindestens n = 8 erreicht, in dem der Strömungsverlauf aufgrund der baulichen Form bereits vorgeprägt ist. Ein Optimum der Blasbedingungen liegt bei Blasraten knapp unterhalb einer Tropfenversprühung. Die Vorgänge in Kaskadenquerrichtung und die weitere Verbesserung eines Rinnenreaktors, der technisch einfacher und kostengünstiger zu gestalten wäre, bleiben Gegenstand weiterer Untersuchungen.
Theoretical analysis of plastic deformation of non‐homogeneous materials
Authors: Malinowski Zbigniew , Szyndler Robert 
Published: December 2016

This paper is concerned with the solution of the problem of non‐homogeneous material deformation. It has been assumed that the deformed material is composed of a finite number of rigid‐plastic bodies with strain hardening.For description of the shape and plastic properties of such a material isoparametric four‐node elements have been applied, whereas for velocity field approximation Hermitian shape functions of third degree have been used as well as bicubic rectangular elements generated before every computation step after transformation of material longitudinal section into square. The plastic deformation of bimetallic specimens was analysed consisting of a core tightly fastened in a ring made of material of lower yield stress and subjected to free upsetting. Minimum non‐uniformity of deformation was obtained for specimens of a core radius equal to about 0.6 of the specimen's initial radius.
A new model on K2O solubility in blast‐furnace slags
Authors: Bergman Åke 
Published: December 2016

The solubility of K2O in blast‐furnace type slags in equilibrium with a reference slag is derived from the potassium oxide capacity as given by the slag's optical basicity. Optimizing of the blast‐furnace slag and the relation between the elements is discussed.Die Löslichkeit von K2O in Hochofenschlacken im Gleichgewicht mit einer Referenzschlacke wird aus der Kaliumoxidkapazität, die durch die optische Basizität der Schlacke gegeben ist, hergeleitet. Die Verbesserung der Hochofenschlacke und die Beziehung zwischen den Elementen wird diskutiert.
Flow field and mixing with eccentric gas stirring
Authors: Mietz Jürgen , Oeters Franz 
Published: December 2016

Measurements of the flow pattern using laser‐doppler‐anemometry were performed in a water model system of a gas‐stirred ladle with different locations of the gas injection nozzle. The intensity of the fluid flow is determined by the gas flow rate, its pattern is given by the position of the nozzle. Dead zones at the bottom of the vessel occurring with centric gas injection can be avoided by using an eccentrically positioned nozzle.For eccentric stirring mixing can be described theoretically using a simple tank‐in‐series model with recirculation.
Bildung und Wachstum von Ermüdungsrissen in Druckbehältern – experimentelle und rechnerische Bestimmung
Authors: Keller Hans Peter 
Published: December 2016

Im Rahmen von Schwellversuchen an acht Hochdruck‐Transportbehältern aus 34 CrMo 4 konnte die Bildung von Ermüdungsrissen an Starterkerben am besten mit der Gleichstrompotentialmethode, aber auch mit Kerbaufweitungsmessungen, erfaßt werden. Da die zur Rißbildung erforderliche Anrißlastwechselzahl mit Konstanten aus der Literatur für einen ähnlichen Werkstoff nur ungenau zu berechnen war, wurden aus den Versuchen geeignetere Konstanten abgeleitet.Mit einem auf der Basis bruchmechanischer Beziehungen aufgestellten relativ einfachen Rißwachstumsprogramm wird die Lastwechselzahl zur Ausbreitung halbelliptischer Oberflächenrisse in Behältern unterschätzt, wenn die Lastgrenzen beim Schwellvorgang konstant bzw. die Unterlast angehoben wurde. Bei Absenken der Oberlast ist die Unterschätzung deutlich größer, da die Verringerung der Rißgeschwindigkeit durch das von der hohen Last erzeugte Druck‐Eigenspannungsfeld nicht berücksichtigt wird.
Solubility of titanium nitride in delta iron
Authors: Kunze Joachim 
Published: December 2016

Titanium nitride in microalloyed steels can be formed already in delta iron, as can be shown by thermodynamical calculations basing on measurements of the solubility in austenite or in the melt. The solubility products calculated with respect to delta iron differ up to one order of magnitude. Therefore, between 1420 and 1510°C a direct measurement was performed on pure Fe–Ti–N alloys yielding a solubility product (related to the composition TiN1,0) of log LTiNα/δ = −17205/T + 5.56. It is identical with that one calculated from the solubility in liquid iron.The differing results of calculations basing on the solubility in austenite are attributed to incorrect data of the Gibbs free solution energy of titanium in austenite. Starting from the present measurements and from the data reported with respect to pure titanium and to the nitrogen solubility a Gibbs free solution energy GTi,γH(x) – GTi,γR = −40294 − 13.66. T[J/mole] was deduced which is more negative than previous data.
Investigation of strain‐inhomogeneities during hot flat rolling – influences on the microstructure evolution
Authors: Lachmann Lutz , Zouhar Gustav 
Published: December 2016

In this paper results of the influence of the material flow on the microstructural evolution of austenite during hot flat rolling are presented. Material flow is investigated by means of rolled specimens, which are prepared with a square‐grid in the middle of the plate. Analyses of the microstructure were applied to elucidate the evolution of the prior austenite structure in thickness direction of the rolled specimens. The inhomogeneous deformation in thickness direction in combination with algorithms for the calculation of the microstructural evolution gives more detailed information on the occurrence of microstructural inhomogeneities compared to the usually applied strip‐model.The inhomogeneous deformation over the thickness of a rolled sheet can be described with sufficient accuracy by means of the strain model according to Zouhar and Lachmann.
The basic concepts of texture investigation in polycrystalline materials
Authors: Bunge Hans‐Joachim 
Published: December 2016

Polycrystalline materials consist of grains which may have different sizes, shapes and arrangements to be observed under the microscope as well as different crystal orientations observed by diffraction methods. The orientation parameters of the crystallites are subsumed under the term texture. The main textural quantities are the orientation distribution function ODF of the crystallites and the misorientation distribution function MODF of grain‐ and phase boundaries. Textures are being formed in materials by all kinds of anisotropic solid state processes and they have influence on all kinds of anisotropic material properties. Textures can be measured grain‐by‐grain or using polycrystal diffraction methods. The appropriate radiations are X‐rays, electrons and neutrons.Finally, some examples are given concerning martensitic transformation in FeNi‐alloys, shape memory alloys, cross‐rolling of Armco‐iron, biaxially stretched polyethylene, and HTc superconductors.
Modelling deformation texture formation by orientation flow fields
Authors: Klein Helmut , Bunge Hans‐Joachim 
Published: December 2016

Model calculations of the development of straight and cross‐rolling textures were carried out. The texture is represented in terms of a series of expansions. The changes of the texture coefficients by a small deformation step can be expressed in terms of the coefficients themselves multiplied by a texture change matrix [α].Integration over the deformation degree η from any starting texture thus gives the deformation texture formation. In the present calculations, the fully constrained Taylor model was used (but other models can equally well be chosen). This model has no unique solutions for most orientations, i.e. it allows several different orientation changes for the same starting orientation. It was shown that this effect is essential in order to obtain model textures which do not only agree in type but also in magnitude with experimental textures.
Influence of hot‐rolling conditions on texture development in deep‐drawing steels
Authors: Därmann‐Nowak Cornelia , Engl Bernhard 
Published: December 2016

As the textures of deep‐drawing sheet steels are important for certain material properties the purpose of this paper was to take a closer look at the hot‐rolling, cold‐rolling and annealing textures of different deep‐drawing steel grades. Several Al‐killed mild steels and vacuum‐degassed Ti‐IF steels have been hot rolled in the mill varying the finishing temperature (FT). After coiling, cold rolling and short‐time annealing the textures at different thickness levels have been measured by means of (110)‐pole figures and orientation distribution functions (ODFs).For both steel groups the textures at the surface of the hot strip exhibit a more or less pronounced shear type character. Towards the mid‐thickness level (with lower FT more clearly) typical (cold‐) rolling textures exist characterized by a strong {001}<110> orientation and in the Ti‐IF steels additionally by a significant {112}<110> orientation density. In the case of high FT cold rolling and annealing lead to favourable {111}‐textures where deep‐drawing application is concerned. For the Al‐killed steels lowering FT results in diffuse recrystallization textures whereas in the Ti‐IF steels a sharp texture with near {223}<582> orientations can be observed which have not been known for these steels before. The results prove that the hot strip textures can be of great importance for the resulting annealing textures and the according material properties.
Metallkundliche Untersuchungen am Grundwerkstoff und an Schweißverbindungen des 9%‐Chromstahles X 10 CrMoVNb 9 1
Authors: Brühl Fritz , Cerjak Horst , Schwaab Paul , Weber Heinz 
Published: December 2016

Umfangreiche Untersuchungen zur Ausweitung des Einsatzbereiches warmfester ferritischer Stähle mit 9 bis 12 % Cr auf 600 °C führten zur Entwicklung des Stahles X 10 CrMoVNb 9 1 (P 9 1 bzw. T 9 1 nach ASTM‐A 335). Wegen der hohen Einsatztemperaturen treten unter Zeitstandbeanspruchung Gefügeänderungen auf, die am Grundwerkstoff und an Schweißverbindungen metallkundlich untersucht wurden.Im üblichen Lieferzustand weist der Stahl T 9 1 ein Gefüge aus angelassenem Martensit mit Ausscheidungen von Chromcarbiden M23C6 auf den Grenzen der Martensitlatten und feinen, sowohl kohärenten wie inkohärenten Niob‐Vanadin‐Carbonitriden vom Typ MX im Korn auf. Unter Zeitstandbeanspruchung scheidet sich weiteres M23C6 und MX sowie zusätzlich die Laves‐Phase aus. Die kohärenten MX‐Ausscheidungen beginnen zu überaltern. Erholung und Rekristallisation werden beschleunigt. Das Zeitstandverhalten dürfte im wesentlichen durch die MX‐Ausscheidungen bestimmt werden, wobei das Mengenverhältnis der Elemente Vanadin, Niob, Kohlenstoff und Stickstoff von erheblicher Bedeutung sein sollte.In Schweißverbindungen bildet sich die Zeitstandschädigung in der Regel in der WEZ nahe der Grenzlinie zum unbeeinflußten Grundwerkstoff aus. In diesem Bereich führt die kurzzeitige Erwärmung auf Temperaturen wenig über A1 zur Bildung eines kohlenstoffarmen Austenits, da praktisch noch keine Carbide in Lösung gehen. Nach der Abkühlung liegt dann ein sehr weicher Martensit vor, der zudem beim üblichen Anlassen auf Temperaturen um 750 °C praktisch vollständig rekristallisiert.
Beschreibung von Ver‐ und Entfestigungsvorgängen am Beispiel austenitformgehärteter Stähle mit Hilfe von Fließkurven
Authors: Bleckwedel Axel , Schrader Hartmut , Kunze Hans‐Dieter 
Published: December 2016

Fließkurven beschreiben das Formänderungsvermögen von Werkstoffen. Gleichzeitig liefern sie Informationen über die Wechselwirkung zwischen der Ver‐ und Entfestigung, wobei diese beiden Eigenschaften temperaturabhängig sind.Fließkurven wurden an Stählen aufgenommen, die sich im wesentlichen in ihrem Kohlenstoffgehalt unterscheiden. Die Bestimmung der Formänderungsfähigkeit erfolgte bei Temperaturen, die denen entsprechen, bei denen eine Austenitformhärtung vorgenommen wird. Die mathematische Beschreibung der Fließkurven läßt erkennen, daß zunächst mit steigender Umformtemperatur die Verfestigungsrate abnimmt. Der Kohlenstoffgehalt erhöht dagegen die Verfestigungsrate. Die dynamische Erholung wird mit wachsender Umformtemperatur beschleunigt, ebenso mit steigendem Kohlenstoffgehalt.
Evaluation of friction under hot working conditions in a high temperature test rig
Authors: Lundberg Sven‐Erik , Waldén Bertil 
Published: December 2016

A new high temperature test rig was designed and constructed. In a first series of tests it was shown that by proper choice of testing parameters, wear mechanisms similar to those in rolls in operation could be achieved. By comparison of frictional values evaluated from experiments in the test rig to values evaluated from ring upsetting tests, an attempt is made to establish the high temperature test rig experiments as a method for simulation of the tribological situation in hot rolling. The coefficient of friction μ was evaluated and fairly good agreement was found with frictional values from ring upsetting tests. However, it is doubtful whether μ is a relevant measure of friction in hot working processes, and in the ring upsetting tests also the friction factor m was evaluated. Evaluation of m‐values from the test rig experiments might be possible. However, such an evaluation claims both a correct shear yield stress value of the hot material and a relevant description of the contact surface area. Since no plastic deformation occurs in the test rig a “semi‐plastic” state must be established and verified. Different attempts can seem realistic, but it is obvious that the evaluation of m, using a “semi‐plastic” state can be manipulated by the choice of conditions by calculating the shear yield stress. Furthermore, it is not clarified whether the Hertzian theory of elastic contacts is valid for a temperature of 1000°C. Thus m‐values evaluated from the test rig have no meaning and the frictional conditions must be characterized by the coefficient of friction μ.Since both relevant frictional and wear conditions are obtained, the high temperature test rig can be used for simulation of roll wear and for the development of new, more wear resistant roll grades.
Low‐cycle fatigue of X 2 NiCoMo 18 12 and X 10 NiCrAITi 32 20
Authors: Detert Klaus , Adolfs Rainer 
Published: December 2016

The low‐cycle fatigue and short crack‐growth behaviour of an ultra‐high strength maraging steel and a high‐nickel austenitic steel have been studied. The tests were performed in a laboratory environment at room temperature in push‐pull cycles with constant strain amplitudes of 0.25 to 2 %. Short crack‐growth investigations were performed using bending specimens loaded by a resonance bending machine. Crack growth was measured using the replica method.The cyclic and tension stress strain behaviour has been compared. Fatigue tests were interpreted according to the recommended practice of ASTM‐E 606‐80. First microcracks were observed after 10 to 70 % of the fatigue life.
Thermal modelling and stress analysis in the continuous casting of arbitrary sections
Authors: Aboutalebi M. Reza , Hasan Mainul , Guthrie R. I. L. 
Published: December 2016

A three‐dimensional parabolic heat conduction model has been developed to analyze heat transfer and solidification in variously shaped continuous casters. A fixed grid source based enthalpy method was used to model solidification during a casting process. In order to correctly model arbitrary cross‐sectional shaped castings, a body‐fitted coordinate transformation (BFT) technique was employed to transform the physical space on to a rectangular computational domain. The transformed governing equations and boundary conditions were solved in the transformed plane. Two arbitrarily shaped casters, having dog‐bone, and hexagonal cross‐sections, were tested in this study. The governing equations were discretized using the control‐volume finite difference approach, wherein an implicit solution technique was employed to solve the set of discretized algebraic equations.From the temperature field predicted by heat flow model, a quasi‐non‐linear stress analysis was carried out within the solidifying shell of the beam blank (dog bone) section. The effect of roller arrangement on the distortion of solidified shell was investigated.
Water model simulation of tundish flow under varying conditions
Authors: Godiwalla K. M. , Sinha S. K. , Sivaramakrishnan C. S. 
Published: December 2016

Water model studies have been conducted to characterise the flow conditions in continuous casting tundishes under conditions of open and submerged nozzles. In this investigation simulations of practical problems of flow interruptions from the ladle, thermal inversions due to uninsulated ladle, and pneumatic agitation near the tundish end wall were conducted.The studies showed that incorporation of suitable flow control devices brings about homogenisation of temperature and composition between strands in the above cases. This study also showed that agitation of the liquid at the end wall reduces the extent of stagnant zone in the tundish.