bluuebunny/crossref_metadata_2025 huggingface dataset:
The application of a glow discharge mass spectrometer in the steel industry
Authors: Charalambous Peter Michael
Published: December 2016

With the VG 9000 glow discharge mass spectrometer (GDMS), major, minor, and trace elemental constituents in conducting and semiconducting materials can be measured directly. The instrument has been developed by a combination of two well founded and proven techniques; namely, a glow discharge cell for the production of ions and a double focussing mass spectrometer designed for high resolution and high sensitivity. The glow discharge cell offers the advantage that the sputtering action and the subsequent ionisation which occur, lead to minimal matrix dependency and a narrow range of sensitivity factors across the entire periodic table. The VG 9000 GDMS has been sucessfully employed to analyse a wide range of materials including steel. For most elements the detection limits are in the ppb range. Carbon, nitrogen and oxygen have been analysed successfully to ppm concentration levels. The glow discharge mass spectrometry has considerable potential for the steel industry, offering a high level of precision together with high speed of operation.
Thermisches Betriebsverhalten einer Bandsinteranlage
Authors: Krumm Wolfgang , Fett Franz N.
Published: December 2016

Es wird ein vereinfachtes mathematisches Modell vorgestellt, mit dessen Hilfe das thermische Betriebsverhalten einer Bandsinteranlage in Abhängigkeit verschiedener Parameter wie Koksgrusgehalt oder Feuchte der Sintermischung beschrieben werden kann. Das Modell enthält als Grundgleichung die instationäre Wärmetransportgleichung, die mit einem modifizierten Newton‐Euler‐Verfahren gelöst wird. Es ist so konzipiert, daß es in ein umfassendes Energiemodell für ein Hüttenwerk integriert werden kann. Es dient damit im weiteren Sinne als Hilfsmittel für die Energiesteuerung im Hüttenwerk.

Durch Simulationsrechnungen wird der Einfluß von Wärm‐ und Wärmebehandlungshauben über dem Sinterband auf die Leistungsfähigkeit der Sinteranlage aufgezeigt. Je nach Abdeckungsgrad des Sinterbandes durch Wärmhauben und den dort herrschenden Temperaturen kann bis zu 15% Koksgrus eingespart werden.
A thermodynamic study of MgO—P2O5 slags by means of solid‐oxide galvanic cell at 1673 K
Authors: Iwase Masanori , Akizuki Hiroshi , Fujiwara Hiroyasu , Ichise Eiji , Yamada Noriaki
Published: December 2016

An electrochemical method was tested in order to find a suitable experimental technique for the determinations of the activities of P2O5 in molten fluxes used for external dephosphorization of hot metal. This technique consists of equilibrating phosphorus‐containing copper with molten slag and measuring the equilibrium oxygen partial pressure by means of solid state galvanic cells. The activities of P2O5 in MgO—P2O5 were determined with this technique.
Effect of liquid zinc on Armco iron with relevance to pots used in galvanizing
Authors: Prakash Satya , Tewari Vinay Kumar , Gupta Akhil
Published: December 2016

The present investigation deals with the comparative study of liquid zinc attack on Armco iron and Tisco A grade iron within a temperature range of 450°C to 550°C. The effect of variables, e.g. time of contact, temperature, on weight loss of iron for a similar geometry of specimens has been studied and discussed. The maximum weight loss of iron has been found at 500°C for both the irons. It has been observed that even a slight variation in silicon content (on increase) appreciably increases the rate of attack on iron.
Influence and role of potassium in the reduction of hematite with CO/CO2
Authors: Roederer Jeanne , Dupré Bernard , Gleitzer Charles
Published: December 2016

Potassium is known for having a favourable role in the reduction of hematite, either pure or as ore and a detrimental action on the crystals’ mechanical properties. However, several different interpretations have been put forward by previous authors: softening of the gangue, modification of the sintering process, consequences of the alkali penetration into the oxide lattices. Hence new data are desirable and have been recorded, with pure hematite crystals as well as with an hematite ore and with two doping techniques: immersion in a K2CO3 solution, or introduction of potassium components in the reducing gas. Microstructure investigation shows that potassium favours porous magnetite growth rather than lamellar growth and concentrates in a sublayer of magnetite at the inner interface. In fully reduced crystals, potassium lies mainly in the core of the particle. When the interface has a so‐called topochemical configuration, the shrinking core model provides the rate constants as a function of temperature. Arrhenius plots lead to the conclusion that potassium significantly lowers the activation energy. The proposed interpretation is based on the transient formation of KFe11O17, which is revealed by 3 different observations. It may act as a nucleation catalyst, thanks to easy epitaxy with Fe2O3. This is consistent with the change to porous rather than lamellar domains when potassium is brought into play and with the increased crystal fracturation. Hematite ore is less sensitive to potassium because its silica gangue behaves as a trap for it, as shown by treatment with HF before reduction.
Influence and role of potassium in the reduction of hematite with CO/CO2
Authors: Roederer Jeanne , Jeannot François , Dupré Bernard , Gleitzer Charles
Published: December 2016

In most shaft furnaces, there is some overlap between hematite‐magnetite and magnetite‐wustite single reactions, due to thermodynamic conditions prevailing during burden movement and to the texture of pellets and/or sinters. Hence, we have investigated the action of potassium on hematite ore and pure crystal reduction with CO—CO2, from 700°C to 1000°C, and with CO/CO2 = 30/70 and 50/50.

With or without potassium reduction proceeds in two successive steps, where the first seems to be much faster than the second. But actually the recorded kinetic data correspond to the same order of magnitude for the two reduction rates, especially at high temperatures. Consequently the usual Bessières model does not apply. This is partly due to the nontopochemical interface in the magnetite‐wustite step. As care has been taken to avoid any reactant starvation, a hypothesis which would encompass all results in a consistent picture is the drop of CO partial pressure in the very outer part of the magnetite layer. The action of potassium on the hematite‐magnetite step is in agreement with oberservations reported in the preceding article: finer texture, greater surface and reactivity, easier gas access. Consequently these features favour an easier reaction in the second step, which proceeds within the Uniform Internal Reaction regime.
Einfluß des Erweichungsprozesses auf die Geschwindigkeit der Reduktion von Sinter mit Wasserstoff
Authors: Król Leszek , Dankmeyer‐Łαczny Jadwiga , Węgrzyn Janusz
Published: December 2016

Im vorliegenden Beitrag wurde der Einfluß des Erweichungsprozesses auf die Reduktionsgeschwindigkeit von Sinter untersucht. Dabei wurde die Reduktionsgeschwindigkeit von Hochofensinter in einem Temperaturbereich um den Erweichungspunkt bestimmt. Es wurde ein rapider, mit dem Erweichungseffekt wie auch mit dem Porositätsschwund verknüpfter Geschwindigkeitsrückgang festgestellt. Diese Erscheinung findet in einem Temperaturbereich statt, der den Temperaturen des Erweichungsbeginns beim untersuchten Sintermaterial im vorreduzierten Zustand entspricht. Somit ist der Erweichungsvorgang als grundlegende Ursache für die festgestellte Abnahme der Reduktionsgeschwindigkeit zu betrachten. Mikroskopische Direktbeobachtungen der Reduktion von Sinter im Erweichungszustand zeigten Erscheinungen, die zu einem Porositätsschwund führen. Messungen des Porenvolumens und der spezifischen Porenoberfläche an Sinter – vor wie nach abgeschlossener Erweichung und Reduktion – bestätigten die Porositätsabnahme. Diese erschwert den Reduktionsgaszufluß zu den Eisenoxiden und verlangsamt so die Reduktionsgeschwindigkeit.
Entschwefelung von gerührtem und ungerührtem Roheisen mit kalkreicher Schlacke unter oxidierender Gasatmosphäre
Authors: Schürmann Eberhard , Erz Hans Peter , Heimann Klaus
Published: December 2016

Aus Betriebsergebnissen bei der Pfannenentschwefelung ist ein negativer Einfluß oxidierender Gasphasen bekannt. Daher war es das Ziel der eigenen Untersuchungen in einer geeigneten Apparatur die Wirkung oxidierender Bedingungen in der Gasphase sowohl auf den Verlauf des Schwefelabbaues in der Schlacke als auch des Schwefeltransportes aus dem Roheisen in die Schlacke zu untersuchen.

Oxidierende Gasphasen erwirken bei der Pfannenentschwefelung an der Phasengrenze Schlacke/Gas eine Oxidation des Schwefels aus der Schlacke, ohne jedoch bei ruhender Schlackenschicht ein Oxidationspotential in der Schlacke aufzubauen, das bis zur Phasengrenze Roheisen/Schlacke durchgreift und dort die Entschwefelung des Roheisens durch die Siliciumgehalte stört. Sowohl die Entschwefelung des Roheisens als auch die Oxidation des Schwefels aus der Schlacke werden durch höhere Temperaturen und durch eine Rührwirkung gefördert. Der Schwefeltransport wird bei den ungerührten wie bei den gerührten Schmelzen durch Diffusionsvorgänge gesteuert und auch hier durch steigende Temperaturen und rührende Kräfte begünstigt.
Warmfließkurven austenitischer Chrom‐Nickel‐Stähle
Authors: Salam Hosain
Published: December 2016

Aus den Meßdaten für die im Warmzugversuch ermittelten Warmfließkurven der austenitischen Stähle X 2 CrNi 18 9 (Werkstoff‐Nr. 1.4306) und X 10 CrNiNb 18 9 (Werkstoff‐Nr. 1.4550) wurde mittels Regressionsanalyse eine Berechnungsgleichung für die Fließspannung erstellt. Diese ermöglichte die Berechnung der Fließspannung für beliebige Umformgrade, ‐temperaturen und ‐geschwindigkeiten im Rahmen der untersuchten Bereiche. Die so berechneten Fließspannungen stimmten mit den gemessenen Werten gut überein. Abschließende Gefügeuntersuchungen verdeutlichten den Beginn bzw. Ablauf der Rekristallisation bei beiden untersuchten Stählen: Die Zugabe von Niob behindert danach die Rekristallisation.
Phenomenological theory of the Portevin‐Le Chatelier effect
Authors: Schlipf Josef
Published: December 2016

Starting from the observation that the serrations appearing in the Portevin‐Le Chatelier effect are produced by hopping deformation bands a set of three autonomous equations is derived for the phenomenological variables load, band velocity and deformation profile. Approximate solutions for the three quantities are given and it is shown that a negative strain rate sensitivity is only sufficient, but not necessary for the appearance of serrations. The treatment of the bands as solitary waves is based on the existence of a mechanical equation of state, using the total dislocation density as structure parameter. A discussion of this approach reveals that a full description of the Portevin‐Le Chatelier effect is not possible on the basis of a single structure parameter.
Microstructural changes in a 12% chromium steel during creep
Authors: Eggeler Gunther , Nilsvang Nicolas , Ilschner Bernhard
Published: December 2016

A quantitative metallographic study was performed using transmission electron microscopy (TEM) to describe the microstructural changes in a 12% chromium steel (X 20 CrMoV 12 1) during creep at 650°C. The creep experiments were conducted under constant load conditions corresponding to initial stresses of 175 and 80 N/mm2. The heat treatment for this steel consists of austenitizing followed by tempering which results in a high density of free dislocations within small elongated subgrains with carbides on or very near some of the subgrain boundaries. During creep, the mean subgrain size increases for both the high and low stress levels. Carbide particle coarsening is observed for the low stress level. These processes result in a softening of the microstructure during creep deformation.
Refining of steel melts using alkaline earth metals
Authors: Breitzmann Martin , Engell Hans‐Jürgen , Janke Dieter
Published: December 2016

In secondary refining of steel melts, the use of alkaline earth metals as a slag phase can be of great significance to remove tramp elements of the main groups IV and V. Fundamental data on corresponding refining equilibria and on the solubilities of the alkaline earth metals Mg, Ca, Sr and Ba in iron and iron alloys have been determined by equilibrating the two metal phases, contained in CaO crucibles, under excess argon pressure at 1600°C. The experimental results indicate that tramp elements such as Sn, N, and P are largely transferred from the iron to the alkaline earth metal phase using Ca, Sr or Ba. Equilibrium alkaline earth metal contents are found to be 0.03 % Ca, 0.004 % Sr and 0.0005 % Ba. Solubilities of Ca, Sr and Ba in iron are increased in the presence of Ni and decreased by additions of Cr.

In the potential industrial application, reducing conditions must be provided and excessive vaporization must be avoided by adequate techniques of addition of the alkaline earth metals.
Raffination von Stahl mit einer Calcium/Magnesium‐Legierung
Authors: Gammal Tarek El , Lischka Helmut
Published: December 2016

Die Raffination eines unlegierten, aluminiumberuhigten Baustahls mit Ca/Mg, speziell der Verbindung CaMg2, wurde theoretisch unter Verwendung eines thermochemischen Datenbanksystems (Therdas Datenbanksystem2)) und experimenteller Laborschmelzen untersucht. Die theoretisch aufgezeigten Entschwefelungs‐ und Desoxidationseigenschaften wurden durch die Schmelzversuche bestätigt, bei denen Gehalte von 15 ppm Sauerstoff und 20 ppm Schwefel eingestellt werden konnten. Die Reaktionsprodukte und die möglichen Einschlußmodifikationen konnten durch die Berechnung weitestgehend vorhergesagt werden. Schon bei CaMg2‐Zugaben von 0,01 % werden die Tonerdeeinschlüsse instabil und durch das Behandlungsmittel zu 12CaO · 7Al2O3 bzw. MgO · Al2O3 umgesetzt. Eine geringfügige Erhöhung der Raffinationsmittelangebote auf 0,03 % reicht in der Regel aus, damit auch diese Spinelle und Aluminate ihre Stabilität verlieren.

Die für die Anisotropie der Zähigkeitswerte im Ausgangswerkstoff verantwortlichen langgestreckten, separaten Mangansulfide werden bereits durch geringe Mengen des Behandlungsmittels (≤ 0,1%) beseitigt und liegen nach der Behandlung nur noch vereinzelt in Form kleiner, runder bzw. teilweise elliptisch verformter Einschlüsse der Größenordnung 1–3 μm vor. Andere, nach der Behandlung im Stahl verbleibende Einschlüsse, wie globulare Calcium‐Aluminate, eckige Magnesia‐Tonerde‐Spinelle und besonders häufig meist runde Formen von Kombinationen dieser Komponenten liegen im Bereich von 1–4 μm vor. Der hohe Reinheitsgrad des Werkstoffes führt zu einer Verminderung der Anisotropie der mechanischen Eigenschaften. Da die geringe Löslichkeit von Calcium und Magnesium im flüssigen Stahl keinen Aufbau eines Reaktionsmittelvorrates in der Schmelze erlaubt, sollte die Raffinationsmittelzugabe kontinuierlich erfolgen, wozu sich verfahrenstechnisch Injektionsanlagen und Drahtspulsysteme anbieten.
Berechnung der Ausbauchung beim Brammenstranggießen von Stahl
Authors: Duoming Luo
Published: December 2016

Es wird ein Modell zur Berechnung der Ausbauchung einer Bramme zwischen den Stützrollen vorgestellt. Diesem Modell liegt die elementare Biegetheorie zugrunde. Es werden verschiedene Annahmen für Randbedingungen an den Rollen betrachtet. Außerdem werden bei den Rechnungen verschiedene Materialgesetze benutzt. Die unter den unterschiedlichen Annahmen erhaltenen Ergebnisse werden mit Messungen an Anlagen verglichen und erörtert.
Hot deformation‐enhanced globularization of pearlite
Authors: Kaspar Radko , Kapellner Werner , Lang Cestmir
Published: December 2016

A plain high‐carbon steel (0.74% C) was used to study the globularization (spheroidization and coalescence) of pearlite. In order to induce and/or enhance this process, specimens were deformed in the temperature range of austenite‐to‐pearlite transformation. It was found that only hot deformation applied after the completion of pearlite transformation leads to spheroidization of pearlite. The rate of this process is accelerated by a factor of 104 compared with annealing without deformation. The kinetics of pearlite spheroidization are dependent on the pearlite lamellae thickness as well as pearlite orientation with respect to the direction of deformation. The final microstructure is, compared with that after a conventional soft annealing, considerably finer, the strength properties thus being largely retained.
Inhibition of the corrosion of steel by acid dihydrazides
Authors: El‐Nabey Beshier Ahmed Abd , Hefny Ahmed Fahmy , Khamis Essam , Khalifa Mohammed Ali , Michael Atef Ramsis
Published: December 2016

The corrosion inhibitory properties of homologous series of acid dihydrazides were studied. Gasometry, potentiodynamic polarization and impedance measurements were recorded for mild steel specimens immersed in 1.0 M H2SO4 or a mixture of 1.0 M H2SO4 + 1.0 M Na2SO4 having the same ionic strength with a pH range from zero to 7. Effect of presence of different concentrations of oxalic, malonic, succinic or pimelic dihydrazide on the corrosion rate of steel in the above solutions were investigated. The results indicated that the protection efficiency of the acid dihydrazides increased with the increase of the number of the methylene groups in the acid dihydrazide molecule. The results are discussed on the basis of the change of each, of the electron density of the donating atoms, of the inhibitor molecules, and the orientation of the inhibitor at the metal surface with the molecular structure of the inhibitor.
Einfluß der Fe2O3‐Gehalte in Frischschlacken auf die MgO‐Löslichkeit bei verschiedenen Sauerstoffpartialdrücken des Schlacke‐Gas‐Gleichgewichtes
Authors: Schürmann Eberhard , Kolm Ingo
Published: December 2016

Untersuchungen an isothermen Sättigungsschmelzen komplexer Stahlwerksschlacken bei 1600°C sollten Aussagen zum Verschleißangriff von Frischschlacken auf MgO‐haltiges Feuerfestmaterial ermöglichen. Dabei wurde besonders der Einfluß von erhöhten Sauerstoffpartialdrücken des Gas‐Schlacke‐Gleichgewichtes (ρo2 von 10° bis 10−8 bar) berücksichtigt, die über eine Zunahme der 3wertigen Eisenanteile in der Schlacke wirksam werden.

Durch Sättigungsschmelzen sind experimentell die bisher nur unzulänglich erforschten MgO‐Sättigungsgehalte in Schlacken bei höheren, durch Ar/O2‐ bzw. CO/CO2‐Gasgemische festgelegten Sauerstoffdrücken untersucht worden. Die MgO‐Löslichkeit steigt im reinen System FeO—Fe2O3—MgO zunächst, ausgehend von einem Grundwert, den die Schlackenzusammensetzung beim Gleichgewicht mit flüssigem Eisen vorgibt, mit steigenden Fe2O3‐Gehalten, solange ein Magnesiowüstit‐Mischkristall die sättigende Phase darstellt. Bei Sauerstoffdrücken ab etwa 10−3 bar aufwärts findet entlang der dann herrschenden Magnesioferrit(MF)‐Sättigung ein Abfall im MgO‐Sättigungsgehalt statt, der aber zum Gleichgewicht mit reinem Sauerstoff hin (ρO2 = 1 bar) wieder leicht ansteigt. Der Magnesioferrit‐Sättigungsbereich wird bei Anwesenheit weiterer Oxide, wie SiO2 und CaO, zurückgedrängt und konnte bereits im System FeO—Fe2O3—MgO—CaO—SiO2 nicht mehr eindeutig nachgewiesen werden. Die erhöhten Löslichkeiten für MgO in stark aufoxidierten Schlacken müssen bei der Beurteilung des Schlackenangriffs auf das Feuerfestmaterial zusätzlich zu den Sättigungsgehalten beim Gleichgewicht mit einer Eisenschmelze in Rechnung gestellt werden.
Application of CAD/CAM in precision forming
Authors: Altan Taylan
Published: December 2016

Computer‐aided techniques are being applied increasingly in designing the tools for metal forming operations. In precision forming these applications are becoming even more useful since. In these cases, dies are more stressed than in conventional forming operations. The practical and proven use of computers in forming technology include: CAD/CAM for die making; transfer of geometric data from the customer's CAD/CAM system to that of the supplier, and vice versa; application of artificial intelligence and expert systems for part and process design; simulation of metal flow, prediction and optimization of process variables as well as analysis of stress in dies and prevention of premature die failure.
Interfacial phenomena and mass transfer in extractive metallurgy
Authors: Olette Michel
Published: December 2016

Interfacial phenomena play an important role in pyrometallurgical processes and knowledge of them and of physical properties involved is necessary for understanding the mechanisms and the kinetics of such reactions. A large number of measurements, performed at Irsid under equilibrium conditions, are presented in this review. Several experimental techniques were used and more particularly:

– Sessile drop method for measurement of liquid metals surface tension and contact angle liquid metal/solid oxide;

– measurement of the contact angle between a liquid slag drop and its liquid metal substrate from which the interfacial tension can be derived;

– direct determination of the interfacial tension from X‐ray pictures of metal drops immersed in the slag.

The systems studied consisted, for the metal phase, of binary and ternary Fe alloys containing C, Mn, Si, O, S and, for the slag phase, binary and ternary mixtures made from CaO, SiO2, Al2O3, MnO, iron oxides, CaF2 and Na2O. A strong effect of O and S potentials was observed. For non‐equilibrium conditions, however, the dynamic interfacial tension between liquid metal and slag decreases sharply when an intense mass transfer occurs through the interface. The potential consideration of interfacial turbulence phenomena (Marangoni effect) in metallurgical reactions is also discussed.
Desulfurization of molten pig iron containing aluminium by powder injection
Authors: Deo Brahma , Grieveson Paul
Published: December 2016

Desulfurization of molten pig iron at 1583K has been carried out by injecting premelted powdered flux containing 40 wt.% lime, 40 wt.% calcium fluoride, and 20 wt.% alumina. Argon was used as a carrier gas. Powdered aluminium was added to the metal bath before, during, and after powder injection to study the most effective method of aluminium‐desulfurization of molten pig iron. Thermodynamic and kinetic aspects of desulfurization in the presence of aluminium have been discussed. A kinetic model was developed to study the extent of transitory and permanent contact reactions. Mass transfer coefficient during transitory contact reaction has been evaluated.
Improving solidification pattern of ESR ingots combined with energy savings
Authors: Shash Yehia Mohamed , Gammal Tarek El , Salamoni Mohamed Ahmed El , Denkhaus Friedrich Alexander
Published: December 2016

Most of the metallurgical effects resulting from electroslag remelting of metal may be divided into two groups, namely, the effects due to the slag/metal reactions taking place and the effects due to the special solidification conditions characteristic of this process. Solidification of ESR ingots takes place progressively as heat is removed from the liquid metal pool via the mold walls. By careful matching of the melting rate with the freezing rate, the desired shallow metal pool is attained, leading to the well known directional solidification pattern with consequent improvement in properties of the steel. The choice of power parameters is limited by a compromise between the need for a high melting rate for economic reasons (costs) which may tend to give a rather deep metal pool and the need for a shallow metal pool to obtain optimum metallurgical properties. In this process only a relatively small amount of the total energy input is actually utilized to melt down the metal. The major part of the energy is lost from the slag and metal pool to the water cooled mold.

In this paper the results of numerical and experimental investigations are presented, setting out a simple method of saving energy and controlling the solidification pattern of the ingot. This method involves the addition of solid particles to the melt to utilize the surplus energy evolved in the central area of the slag bath.
Problem of stress and strain concentration in the entry and exit planes in the drawing process
Authors: Sadok Lucjan , Paćko Marek , Pietrzyk Maciej
Published: December 2016

The paper discusses the problem of stress and strain concentration in the entry and exit planes during the drawing process. Earlier investigations carried out by Pierlin, Pawelski and Armstroff as well as Chen and Kobayashi's finite element analysis are reviewed. Authors’ calculations based on the rigid‐plastic finite element approach are compared with experimental and theoretical results published by Pawelski and Armstroff. Solution for rigid‐plastic material behaviour confirmed the die pressure increase in the entry and exit zones questioning Pierlin's suggestion that the elastic strains are responsible for pressure concentrations. Analysis of the strain rate distribution led to the presumption that pressure increase is due to the strain rate concentrations in the areas close to the entry and exit zones.
Metal flow in compression of tubular parts: predictions made with different computer programs and effect of flow stress data
Authors: Hirt Gerhard , Altan Taylan
Published: December 2016

The study deals with the comparison of three different FEM (finite element method) based codes for simulating the upsetting of a tubular shape. The geometry of this specific part was selected to be very sensitive to variations in flow stress or to errors in the mathematical formulation of metal flow. The results of the study indicated that the available FEM codes are capable of handling two dimensional isothermal and nonisothermal forming problems with reasonable accuracy, provided the input data on flow stress, friction, and heat transfer are also reasonably accurate. Inaccuracies in these data, especially in flow stress, may cause considerable errors in the prediction of metal flow as well as forming loads.
Development in smelting reduction processes
Authors: Papst Gero
Published: December 2016

Corex process is a smelting reduction process to produce hot metal of blast‐furnace quality. Coal is used instead of coke, and this replacement makes production costs of hot metal decrease. Iron ore reduction and melting is separated into two steps: in a melter gasifier reducing gas is generated and melting energy is produced by coal gasification; iron ore is reduced in a shaft furnace. Due to this separation, a great variety of untreated coals can be used.

The Corex process is designed to operate under elevated pressure, up to 5 bar. Reducing gas is generated in a fluidized bed by partial oxidation of coal. After leaving the melter gasifier, the gas is mixed with cooling gas to obtain a temperature suitable for direct reduction, i.e. approximately 850–900°C.

The fines captured in a hot cyclone are re‐injected into the gasifier. Reducing gas is fed into the reduction furnace and ascends through the iron burden according to the counterflow principle. The hot DRI having a temperature of 800–900°C is continuously charged into the melter gasifier, where further reduction is effected and melting occurs. Hot metal and slag drop to the bottom of the melter‐gasifier. Analogous to blast‐furnace practice hot metal and slag are discharged by conventional tapping.
Concept and present state of a coal‐based smelting reduction process for iron ore fines
Authors: Neuschütz Dieter , Hoster Thomas
Published: December 2016

The concept of a two‐stage smelting reduction process is presented. In the first stage highly metallized iron ore fines are produced in a circulating fluidized bed. In the second stage a hot metal is produced in a melter‐gasifier where – together with metallized ore – coal and oxygen are injected to generate the required heat and the CO‐rich reducing gas. The process was tested stepwise in pilot scale installations. Although only a reduction temperature of 830 °C instead of the required 880–900 °C could be realized in the pilot unit, test results make it very probable that a metallization of 90% can be reached with any fine ore without sticking problems, if the ore is covered with a carbon layer by CO decomposition in a pretreatment stage with the reduction offgas at 500–600 °C. The CO decomposition on the fresh ore leads to a high gas utilization which renders a CO2 washing stage and gas recycling unnecessary.

To prove the technical and economic feasibility of the combined process, the next development step should be the design and operation of a larger pilot plant with a capacity of at least 5 t hot metal/h for continuous and joint operation of both the melter/gasifier and the reduction stage.
Steelmaking considerations using smelted iron
Authors: Koros Peter J.
Published: December 2016

Iron produced with several of the “in‐bath smelting” technologies may differ from the output of conventional blast furnaces. Carbon content may be driven to below saturation, oxygen content will be high so that a) silicon may be near nil, and b) the sulfur content can reach upward of 10 times higher than achieved with the coke‐oven/blast‐furnace route. These conditions point to the need for new approaches for conversion of this intermediate liquid into steel.
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.
Calculation of the interfacial properties of liquid steel – slag systems
Authors: Cramb Alan W. , Jimbo Itaru
Published: December 2016

The rates of many high temperature metallurgical reactions are strongly influenced by interfacial phenomena and to determine reaction rates it is necessary to have an accurate model of interfacial properties. In this article, the factors governing interfacial tension in slag‐metal systems will be briefly discussed and, a model based on the combination of the Gibbs and Langmuir adsorption isotherms with Girifalco and Good's expression for the interfacial tension between immiscible liquids, will be shown to be consistent with current literature values and allow the calculation of both the interfacial tension and the contact angle between liquid slags and liquid iron in the CaO–CaF2–SiO2–Al2O3system. The application of this approach to systems containing FeO in the slag and carbon in the metal are then discussed.
Bath smelting with oxide‐sulfide melts
Authors: Elliott John F.
Published: December 2016

Oxide‐sulfide melts are employed for bath smelting of iron ores. The reaction mechanisms in the system Fe–O–S with carbon monoxide are investigated. Oxide‐sulfide phases have the advantage of high solubility of wustite and magnetite and dissolved iron oxides can easily be reduced.
Mixing with heat and mass transfer in metallurgical systems
Authors: Oeters Franz
Published: December 2016

In the first part of this paper, general aspects of research needs in the field of heat and mass transfer in metallurgical systems are discussed as this field is important for innovative iron and steelmaking processes. In the second part, special research needs are mentioned which have to be considered under the view of the first part.
Conclusions on the development of smelting reduction
Authors: Fine H. Alan , Fruehan Richard J. , Janke Dieter , Steffen Rolf
Published: December 2016

The present paper summarizes the results of the US‐German Symposium on “Innovative Iron and Steel Making Processes”. A survey is given on the state‐of‐the‐art technology as well as the state and further needs of research.
Turbulence characteristics of a gas‐stirred steel bath outside the bubble plume
Authors: Chung Soon‐Hyo , Lange† Klaus W.
Published: December 2016

In order to understand the turbulence characteristic in melts stirred with injected gas, the relations for effective diffusion coefficient, turbulent kinetic energy and mean size of energy containing eddies were derived from the energy equation with an extended flow field for the steel bath, where strong bubble plume and surface currents are present. 67 or 23% of the energy is dissipated in the bubble plume or surface flow zone. An increasing entrainment coefficient leads to higher values of energy dissipation factor, effective diffusion coefficient and mean size of energy containing eddies, but to low degrees of turbulence. With increasing bath aspect ratio the energy dissipation factor increases, but the degree of turbulence decreases. With increasing gas flow rate and bath height the effective diffusion coefficient enlarges. Increasing bath size leads to large mean size of energy containing eddies, which reaches 17% of the bath diameter at high gas flow rates.
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.
Incremental forging – flexible metal forming process improves utilisation of material and energy
Authors: Welschof Klaus , Kopp Reiner
Published: December 2016

Incremental forging is a flexible bulk‐forming process offering material and energy savings when compared to present‐day machining operations. Due to the forming load, which is low in comparison to the die forging method, and the use of simple tooling it is possible to enhance the application of conventional, integrated and computer‐controlled hand‐forging equipment by the incremental forging of components with flat basic shapes.
Effect of molybdenum on tempered martensite embrittlement of medium carbon Si‐Mn steels
Authors: Fu Ming , Qiu Yaojian
Published: December 2016

This paper reports a study of the effects of molybdenum on tempered martensite embrittlement (TME) of medium carbon Si‐Mn steels. The study employed standard U‐notch impact tests, scanning electron fractography, transmission electron microscopy, Auger electron spectroscopy, and dilatometric measurements. It is shown that the addition of molybdenum to Si‐Mn steels does not eliminate TME, but molybdenum acts to decrease the ductile‐brittle transition temperature (DBTT), thus making the impact test temperature for revealing TME lowered. Furthermore, the deferring role of molybdenum on TME is observed. In the molybdenum doped steels the TME embrittlement trough is displaced to a higher tempering temperature. The embrittlement is found to be concurrent with the replacement of ∊‐carbide by cementite during tempering. In the molybdenum doped steels the displacement of TME to a higher tempering temperature is seen to be associated with the role of molybdenum retarding cementite precipitation.
Microstructural hot corrosion behaviour of austenitic Fe‐29.7Mn‐8.7Al‐1.04C alloy in fused Na2SO4 and Na2SO4‐NaCl mixture
Authors: Tjong Sie Chin
Published: December 2016

A short‐time hot corrosion test was performed on the austenitic Fe‐29.7Mn‐8.7Al‐1.04C alloy in sodium sulphate at 900°C. The corrosion scales formed on the alloy investigated were studied by scanning electron microscopy and X‐ray mapping techniques. The hot‐corrosion scales morphology of the austenitic Fe‐29.7Mn‐8.7Al‐1.04C alloy were characterized by the formation of Al2S3 and α‐MnS sulphides at and beneath the internal alumina scale. No fluxing of the scales was observed. The effect of the addition of sodium chloride to the fused sodium sulphate on the hot corrosion scales morphology was also investigated.
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.
Monitoring two‐phase mixing in a 1:7 scale model reactor during combined blowing processes
Authors: Siemssen Rinnert , Lange (†) Klaus W.
Published: December 2016

In the field of metallurgical processes there has been little knowledge on slag‐mixing and the phenomena accompanying mixing so far, when a model slag influences the mixing process in the model bath. However, these phenomena should be detected, investigated and taken into consideration for further process optimization and modelling. Thus, the present paper is a contribution to the investigation of slag‐mixing in a 1:7 scale model reactor during combined blowing processes. First of all the present paper deals with experimental results, gained in a 1:7 scale model reactor, and it is concerned with dispersion processes. Then global mixing times in the model bath are considered. Furthermore, as method to evaluate local slag‐mixing times these were calculated using the intensity of segregation, a method usually used in chemical engineering and turbulence theory. Special regard is given to the influence of different blowing modes on dispersion degrees, mixing ratios and to a possible explanation of the occurrence of turbulent zones in the model slag.
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.
Scavenging additions of boron in low C – low Al steels
Authors: Messien Pierre , Leroy Vincent
Published: December 2016

Scavenging of boron on nitrogen is almost complete on the hot strip for B/N ≥ 0.7–0.8. Nitrogen ageing does not appear and low coiling can be used (650°C). BN precipitates as polycrystalline aggregates (spherulites) and in association with other precipitates or inclusions. Solute carbon is somewhat reduced in B steels coiled at 650°C but a more important reduction is achieved when coiling at 750°C due to an Fe23 (C, B)6 precipitation in the optimum range 1.0 ≤ B/N ≤ 1.5. Yield stresses (YS) lower than 190 MPa are obtained for optimized compositions of low Al‐B steels coiled at 650°C and continuously annealed (825°C – 60 s – cooling rate: 50°C/s). Further softening is achieved when coiling at 750°C (YS < 160 MPa). Lower ageing (≤ 20 MPa) of B steels coiled at 650°C is also for c.a. steels when compared to low Al grades; bake hardening remains at a high level (> 50 MPa). No ageing is observed in B steels coiled at 750°C of which the bake hardening is reduced (25 MPa). Deep drawability of B steels is improved at reduced C, Al, Mn contents and at higher coiling temperatures; a detrimental effect of a B excess is observed. Low nitrogen contents and reduced Al additions are needed to reach best B steel properties.
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.
Magnetic and other physical properties of X 52, X 60, X 70, and X 80 grade linepipe steels
Authors: Richter Friedhelm
Published: December 2016

The following magnetic properties were determined for X 52, X 60, X 70, and X 80 grade linepipe steels: magnetic induction as a function of magnetic field strength in the form of hysteresis loops, coercive force and saturation magnetisation. In addition, the following physical properties were determined: coefficient of thermal expansion between ‐180 and 400°C, elastic constants between ‐180 or 20 and 300°C, electrical resistivity, thermal conductivity and thermal diffusivity between ‐180 and 300°C. The crystallographic textures of the materials were represented by pole figures.
Representation of thermodynamic properties of multi‐component systems using interaction parameters
Authors: Hajra Jnan P. , Frohberg Martin G.
Published: December 2016

Integral excess free energy of a multi‐component – ternary system has been expressed in terms of the Maclaurin infinite series. The series is subjected to appropriate boundary conditions and each of the derivatives correlated to the corresponding interaction parameters. The partial thermodynamic property of component 1 derived by the use of logarithmic functions together with a geometric progression is presented. The equation is found to be capable of interpreting thermodynamic data over a wide compositional range of the ternary system and is independent of compositional paths. An alternative approach for the determination of generalised relations between interaction parameters to that of Lupis and Elliott has been developed.