bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in precipitation and corrosion characteristics of 18/10Ti austenitic stainless steel exposed to prolonged annealing at 750–850 °C
Authors: Vodárek Vlastimil , Číhal Vladimír , Hubáčková Jiřina , Mazanec Karel 
Published: December 2016

This investigation deals with the analysis of intergranular acicular precipitations by X‐ray diffraction techniques and SEM. Results obtained during analysing acicular precipitate in 18/10Ti steel, isothermally annealed at 750–850 °C, can be summarised as follows:Intergranular needles are constituted by a complex phosphide of M2P type whose chemical composition can be written as (Ti,Cr,Fe,Ni)2P. Crystal growth direction of intergranular acicular M2P particles in austenite is 〈100〉γ. The following orientation relationship was determined between the complex phosphide of M2P type and austenite: . Corrosion testing in boiling 65% HNO3 revealed that there was a relationship between the occurrence of acicular precipitate and a reduction in corrosion rate to a level below 0.5 g m−2h−1.
Fluid flow and mixing in secondary metallurgy
Authors: Oeters Franz , Pluschkell Wolfgang , Steinmetz Eberhard , Wilhelmi Herbert 
Published: December 2016

Mixing in metallurgical vessels is determined by bulk flow, turbulence and diffusion. In this presentation, the main features of mixing liquid steel by gas stirring are discussed. The criteria for bubbling and jetting during gas injection are considered including interaction of powder load on flow regimes. It is of interest to know the domains of bubbling and jetting behaviour in order to minimize the effect of back attack which is responsible for additional wear of bottom linings and tuyere pipes.Quantitative information is given on velocity, the radius and the pumping capacity of the buoyant plume. The relations lead to the conclusion that the gas flow should be apportioned to two or more plugs in order to increase the efficiency of the pumping effect. Furthermore, the macroscopic flow pattern is substantially influenced by the ratio of height to diameter of the ladle. Especially at high ratios dead volumes near the ladle bottom are observed. Further examples for the influence of fluid flow on reactions, dispersing and separating in the ladle and tundish are given.At first approach, mixing time depends on the gas flow rate or on the specific power input. But the details are much more complicated. It is shown that the mixing process can be described by two types of models among others: the turbulent recirculation model and the model of partial volumes. The comparison of calculated concentration‐time‐dependencies with plant results confirms the practicability and usefulness of the model of partial volumes. It is also concluded that the water model results for ladles may be transferred to plant conditions.In total all examples that are discussed emphasize the great significance of model simulations and model calculations as instruments for process improvement and process development.
Lösungsglühen von Carbiden bei relativ niedrigen Temperaturen und Überprüfung mit elektrochemischen Methoden
Authors: González José Antonio , Molina Alberto , Valencia Marcos , Räuchle Fritz 
Published: December 2016

In der vorliegenden Arbeit wird über Wärmebehandlungen zur Lösung von Chromcarbiden als Vorbeugungsmaßnahme zur Verhinderung der interkristallinen Korrosion berichtet. Vor dem Hintergrund einer möglichen Energieeinsparung wurde ein Temperaturbereich gewählt, der knapp unter dem der industriellen Praxis von 1050°C liegt.Gleichzeitig werden die elektrochemischen Untersuchungsmethoden der Anfälligkeit für interkristalline Korrosion den genormten Methoden gegenübergestellt, um die Anwendungsmöglichkeiten und ihre Verläßlichkeit zu bewerten und einzustufen.Die Ergebnisse zeigen, daß dem Kornzerfall durch Wärmebehandlungen bei 950°C entgegengewirkt werden kann. In vielen Fällen wird diese Temperatur, die rund 100°C unter der in der Industrie angewandten liegt, eine bedeutende Energieeinsparung beinhalten. Allerdings ist diese niedrige Lösungsglühtemperatur nur für molybdänfreie Stähle anzuwenden; für molybdänhaltige, nichtrostende Stähle ist bei Gehalten über rd. 2,5 % Mo eine höhere Lösungsglühtemperatur nach wie vor erforderlich.Das elektrochemische E.P.R.‐Verfahren ist eng mit den Versuchen A, C und E der Norm ASTM‐A‐262 verknüpft. Diese Tatsache wie auch die Einfachheit, Schnelligkeit und der zerstörungsfreie Charakter führen die Autoren zu der Überzeugung, daß die elektrochemische Methode ein idealer Test zur Ermittlung der Anfälligkeit für interkristalline Korrosion ist.
Einfluß der Sulfidausbildung auf die mikroskopische Spaltbruchspannung σ*fund Vorhersage der RißzähigkeitKIc
Authors: Dormagen Detlef , Dahl Winfried 
Published: December 2016

An vier Schmelzen des Stahles St 52–3 wurde der Einfluß des Schwefelgehaltes und der Sulfidformkontrolle mit CaSi und Cer sowie an dem Stahl StE 36 der Einfluß der Probenlängen längs, quer und senkrecht auf die mikroskopische Spaltbruchspannung σ*funtersucht. Die Versuche haben gezeigt, daß durch Einführung eines geeigneten Bruchkriteriums die Bestimmung einer temperaturunabhängigen Spaltbruchspannung σ*fmöglich ist. Ein Einfluß des Schwefelgehaltes und der Sulfidausbildung auf σ*fwurde nicht beobachtet.Weiterhin konnte gezeigt werden, daß mit mikroskopischen Werkstoffkennwerten die Vorhersage makroskopischer Bruchparameter möglich ist, wenn der Einfluß der Rißspitzenabstumpfung berücksichtigt wird.
Umformwirksamer Längszug beim Walzen von Langprodukten
Authors: Oehlstöter Gerhard 
Published: December 2016

Weltweit bemühen sich Hersteller und Betreiber von Walzanlagen um eine Intensivierung des Walzvorganges. Bei der Herstellung von Langprodukten ist die Querschnittsreduzierung das Hauptziel beim Walzen. Durch Nutzung des Längszuges zwischen den Walzgerüsten sollen eine Minimierung der Walzstiche und eine Reduzierung der Umformenergie erreicht werden.Ausgehend von der Darlegung der Breitungsverluste beim Streckwalzen von Langprodukten werden neuere Untersuchungsergebnisse dargelegt, die darauf hinzielen, den Längszug zur Erhöhung der Umformwirksamkeit in Kontiwalzstraßen zusätzlich einzusetzen. Drei Wirkungsbereiche zwischen jeweils zwei Walzgerüsten konnten nachgewiesen werden. Unvermeidlich ist die Ausbildung verdickter Enden, deren Form erörtert wird. Auf Möglichkeiten zu deren Einschränkung wird hingewiesen. Für die Senkung von Walzkräften und Walzmomenten werden Ergebnisse aus Labor‐ und Betriebsversuchen mitgeteilt.
Mass transfer between solid and liquid in vessels agitated by bubble plume
Authors: Mazumdar Dipak , Kajani Srikanth K. , Ghosh Ahindra 
Published: December 2016

Mass transfer from solid benzoic acid cylinders to a gas‐stirred aqueous bath has been investigated both theoretically and experimentally. Two typical gas injection configurations, the conventional central injection and the C.A.S. (Composition Adjustment by Sealed Argon Bubbling) were employed and the rates of dissolution of the acid compacts at various locations in the bath were measured at different gas‐flow rates. These demonstrated that the mass‐transfer rates are the highest in the two‐phase region, while elsewhere in the bath, these were found to be practically identical. Furthermore, mass‐transfer rates at the corresponding locations were found to be relatively greater for the conventional central injection than those for the C.A.S. configuration.Distribution of velocity and turbulence intensity in the vessel were computed theoretically using a previously reported calculation procedure. Based on these, values of various relevant dimensionless numbers were estimated so as to assess the adequacy and effectiveness of heat and mass‐transfer correlations reported in the literature. These, however, did not fit with the present experimental observations. For this reason, a new correlation has, therefore, been proposed and it is shown that the experimental data can be described reasonably well by the equation Sh = 0.73 (Reloc,r)0.57 (Ti)0.32 (Sc)0.3. This correlation also embodies more plausible definitions of Reynolds number (Reloc,r) and the turbulence intensity (Ti) in contrast to those reported in literature, since it has been derived using the local resultant mean velocity and the local fluctuating velocity in the fluid.
Experimental studies on hydrogen solubility in liquid ternary iron‐nickel‐chromium alloys
Authors: Mitra Mandaresh , Lange (†) Klaus W. 
Published: December 2016

The hydrogen solubilities in liquid ternary iron‐nickel‐chromium alloys have been experimentally determined by Sieverts’ method. The experimental data have been evaluated with the help of regression analysis (Gauß‐Jordan) and using own published empirical equations (polynomials). With the help of experimentally determined hydrogen solubilities and the coefficients of the polynomials, the concentration dependencies of hydrogen solubilities, interaction coefficients, enthalpies and entropies of hydrogen solution have been determined.The hydrogen solubility increases with increasing temperature and with an increase in the nickel and chromium concentration. The results have been represented as isothermal planes. The hydrogen solubilities in liquid ternary iron‐nickel‐chromium alloys (xCr ≤ 50%) have been predicted with the help of “Central Atoms” model, assuming the concentration dependencies of the “model parameter λ” and selecting the value of the coordination number (Z’ = 10) for each of the “reference elements” iron or nickel.The comparison between the experimentally determined and the predicted hydrogen solubilities in iron‐nickel‐chromium alloys confirms that the prediction of hydrogen solubilities in liquid system iron‐nickel‐chromium can be qualitatively made over a wide range of alloy concentrations (xCr = 50%) with the aid of “Central Atoms” model and with the assumption of concentration dependencies of the “model parameter λ”.
Elektrochemisch kontrollierte Dauerschwingversuche mit dem ferritischaustenitischen Stahl X 2 CrNiMoN 22 5 3 in 3%iger NaCl‐Lösung
Authors: Roeder Erwin , Selzer Ralf , Vollmar Jürgen 
Published: December 2016

Das Dauerschwingverhalten des Stahles X 2 CrNiMoN 22 5 3 (Werkstoff‐Nr. 1.4462) bei Raumtemperatur wurde sowohl an Luft als auch in 3%iger NaCl‐Lösung bei reiner Zug‐Schwell‐Beanspruchung mit einer Prüffrequenz von 25 Hz untersucht. Für glatte Proben wurde hierbei an Luft die reine Zug‐Schwellfestigkeit von 490 N/mm2 ermittelt. Bei korrosiver Belastung betrug die Zeitschwingfestigkeit für N = 107 nur noch 78 % des Wertes an Luft, wobei auch bei noch höheren Schwingspielzahlen mit Probenbrüchen gerechnet werden muß. Vergleichende Untersuchungen an gekerbten Proben ergaben, daß der gewählte Kerbfaktor von 2,0 sowohl für die Versuche an Luft als auch in 3%iger NaCl‐Lösung zu einem Absinken der dynamischen Festigkeit um 10% führte. Die zusätzlich für glatte Proben an Luft ermittelte reine Zug‐Druck‐Wechselfestigkeit betrug 350 N/mm2.Die Auswertung der bei allen Schwingungsrißkorrosionsuntersuchungen in 3%iger NaCl‐Lösung aufgezeichneten Ruhepotentialverläufe zeigte bei Proben, die aufgrund der geringeren mechanischen Belastung nicht zu Bruch gingen, im gesamten Versuchsverlauf einen kontinuierlichen Potentialanstieg. Bei mechanisch höher belasteten Proben dagegen kündigte sich der Probenbruch etwa 105 Schwingspiele vorher durch stark progressive Negativverschiebung des Potentials an.
Material flow in die forging
Authors: Lehmann Gunter 
Published: December 2016

Because of steadily increasing demands on die forging industry the calculation of material flow will be of prime importance in future.The paper presents results of investigations of die‐forged specimens with internal scans of the symetric plane. Using a visioplastic mathematic model, the distribution of velocity, strain, strain rate, temperature, and effective stress is calculated from the measured scanning deformation.Of special interest are the results of temperature distribution in the forged part which depends on the geometrical properties of the die. These results may serve the checking of FEM calculations performed on cylindrical specimens in case of compression.
Emulsification and mass transfer in ladle metallurgy
Authors: Mietz Jürgen , Schneider Stefan , Oeters Franz 
Published: December 2016

Measurements of slag emulsification in gas‐stirred ladles were carried out in cold‐model systems of different geometric sizes. Detaching of slag droplets – necessary for efficient emulsification – only takes place if the flow velocity at the slag/metal interface exceeds a certain level.The use of a centric nozzle leads at high gas flow rates to considerably larger degrees of emulsification than eccentric stirring. The reason of this phenomenon is that the recirculation flow during centric gas injection transports larger amounts of emulsified droplets into deeper regions of the melt while during eccentric stirring there is more time for reseparation of slag droplets into the top slag.Comparing emulsification results with mass‐transfer measurements, the dependence between rate constants as well as degrees of emulsification and Froude number shows similar behaviour.
Effect of the chemical composition of Fe‐Mn‐C‐P alloys on the brittle‐ductile transition temperature in the solidification range
Authors: Chojecki A. , Telejko I. 
Published: December 2016

The brittle‐ductile transition temperature in the solidification range depends on the composition of the phase which solidifies as the last one. The paper presents a thermochemical study of Fe‐Mn‐C‐P system, determining the conditions of crystallisation of carbides, phosphides and the pseudo‐ternary eutectic ML‐M3C‐M3P. Manganese raises the phosphorus concentration in eutectic. The eutectic temperature attains its maximum at about 6% of Mn. Then the brittle‐ductile transition temperature is about 30 K higher than in ternary Fe‐C‐P alloy. A further raise is possible when the alloy is modified by an element forming stable, solide carbide, for ex. titanium.The results of theoretical analysis were verified by experimental work. The influence of titanium on the inclusions appearing in the vicinity of hot cracks of Hadfield cast steel has been studied.
Kinetics of carbon combustion in packings of casting powder
Authors: Schwerdtfeger Klaus , Jablonka Angela 
Published: December 2016

The kinetics of carbon combustion in packings of casting flux have been investigated in isothermal laboratory experiments. At low temperature (300, 400°C) combustion is controlled by chemical reaction, and at high temperatures (600 to 800°C) by mass transfer within the powder packing and in the gaseous space above the packing. Inbetween, there is a range of mixed control.The paper intends to demonstrate how the relevant kinetic parameters can be deduced with rather simple experimental methods. These parameters can then be used in the modelling of the more complex combustion process occurring in real continuous casting.
Phosphorus equilibrium between BaO‐BaF2‐MnO fluxes and ferro‐manganese melts
Authors: Liu Xiaoya , Wijk Olle , Selin Roger , Edström John Olof 
Published: December 2016

The equilibrium distribution ratio of phosphorus between BaO‐BaF2‐MnO slags and Mn(62–73%)‐Fe‐Csat‐P melts has been determined for different slag compositions, oxygen partial pressures and at 1573–1673 K. The results showed that with a certain content of BaO in the slags, the phosphorus distribution ratio increased with increasing oxygen partial pressure up to about 10−17 atm. A high oxygen partial pressure resulted in a substantial oxidation of manganese from metal to slag. The phosphate capacity of BaO‐BaF2‐MnO slags increased with the BaO content and decreased with the MnO content in the investigated slag composition range. A high temperature resulted in a low phosphorus distribution ratio. For a BaO(50%)‐BaF2(47%)‐MnO(3%) slag, the effect of temperature on the phosphate capacity in the range of 1573–1673 K could be expressed as:

urn:x-wiley:01774832:srin01094:equation:srin01094-math-0001The heat of reaction:

urn:x-wiley:01774832:srin01094:equation:srin01094-math-0002was estimated to be −1107 kJ/mole.
Feasibility of fluidized bed CVD for the formation of protective coatings
Authors: Kinkel Stefan , Angelopoulos George N. , Papamantellos Demetrios C. , Dahl Winfried 
Published: December 2016

Attempts have been made to clarify the feasibility of a fluidized bed CVD (FBCVD) process as another method for the formation of cementing and diffusion coatings in order to improve wear, oxidation and corrosion resistance of metals.Treating agent powders consist of a donator, usually a powder of the metal, an alloy or a metal carbide or nitride of the coating forming metal, an activator, usually a halide or alkali metal halides, and a filler oxide, usually Al2O3, SiO2 etc. The precursors of the coating forming metal are formed “in situ” the fluidized bed reactor by the reaction of the donator with the activator. The bed can be fluidized by inert or reactive gas or gas mixtures like Ar, N2, Ar + H2 etc. As the parts can be charged and withdrawn while the furnace is at treating temperature, this process can be integrated into the heat treatment cycles.The FBCVD process was applied for the formation of Ti‐, V‐, Cr‐, Al‐, and Si‐bearing coatings. The produced coatings were dense and uniform over the whole specimen surface. According to the results, the use of the FBCVD process is promising since it can lead to a clean, flexible surface modification technology, combining adaptability with relatively low capital and operational costs.
A mathematical model for estimation of sulphide capacities of multi‐component slags
Authors: Sichen Du , Nilsson Roger , Seetharaman Seshadri 
Published: December 2016

The present work presents mathematical model for the estimation of sulphide capacities. The sulphide capacity, CS is expressed as

urn:x-wiley:01774832:srin01155:equation:srin01155-math-0001where ΔG0 is the standard Gibbs energy change for the reaction,

urn:x-wiley:01774832:srin01155:equation:srin01155-math-0002ξ, being a function of both temperature and composition, is characterized by the system under consideration. By optimizing ξ, the sulphide capacities could be estimated as functions of temperature and composition. The slag composition is described using a modified Temkin approach, where complex polymeric ions are considered as dissociated to simple species. The model has been applied to the binary systems CaO‐SiO2, MnO‐SiO2 as well as the CaO‐MnO‐SiO2 ternary system. The results show that reliable predictions of the sulphide capacities can be obtained using the present model.
Mathematical model for predicting the thermal and mechanical behaviour of rebar during quenching and self tempering
Authors: Kumar Ashok , Singhai L. K. , Sarna S. K. 
Published: December 2016

A mathematical model has been developed to predict the thermal and phase transformation behaviour of plain carbon steel rebars having mass contents of carbon in the range of 0.10 to 0.18 %, during quenching and self tempering process. The model takes into account the operating parameters such as rebar diameter, rolling speed, finishing temperature of rebar leaving the last stand of hot rolling mills. The design features of cooling tube and water flow rate have also been included in the model. The phase transformation kinetics from austenite to martensite at the surface, bainite beneath the surface and ferrite and pearlite in the core has been incorporated in the model. An attempt has been made to predict the yield strength of rebars as a function of chemical composition and volume fractions of different phases.In‐plant trials were conducted at Visakhapatnam Steel Plant for 10 and 18 mm diameter rebars. Tempering temperature was measured and volume fractions of different phases and mechanical properties were determined. A very good agreement was found between measured and predicted volume fractions of martensite, bainite and ferrite + pearlite. Comparison between predicted and measured yield strength values show a reasonably good agreement under industrial conditions.
Application of fatigue precracking methods and their influence on fracture toughness values
Authors: Bohác Igor , Dahl Winfried , Pesek Ladislav 
Published: December 2016

The purpose of this work is to compare three fatigue precracking techniques for SENB specimens containing residual stresses. These are local compression, the use of a high R‐ratio in the fatigue cycle and reverse bending. The possible effects of these techniques on the values of fracture toughness are assessed.The main conclusion is that local compression reduces the measured fracture toughness up to 50 % and various materials have different sensitivities to 1 % plastic strain. Local compression produces also greater scatter of values. Reverse bending does not affect the fracture toughness but requires further research and development. A disadvantage caused by the use of a high R‐ratio is the essential increase in the total precracking time. Uniform fatigue crack front profiles can be obtained by all three methods.
Production of ultra‐high strength wire rod steels by vanadium microalloying
Authors: Eissa Mamdouh , El‐Fawakhry Kamal , El‐Faramawy Hoda , Fathy Ayman 
Published: December 2016

Ultra‐high strength high‐carbon wire rod steels have been produced using vanadium‐microalloying technique instead of the conventional expensive and environment polluting lead patenting treatment. The strength increment attained in the hot rolled steels due to vanadium additions is maintained in the cold drawn wire. By using this technique, high tensile strength levels of 1550‐1600 N/mm2 were attained either by cold drawing of 0.17% V microalloyed high‐carbon steel to 45‐47% reduction or by cold drawing of 0.20% V microalloyed high‐carbon steel to 25‐30% reduction. An equation has been developed to predict the tensile strength from the chemical composition, cooling rate and reduction of area due to cold drawing.A combination of vanadium microalloying and accelerated cooling resulted in additional strength increment due to refining of microstructure and increasing the precipitation strengthening component. Inspite of the decrease in the amount of vanadium precipitates due to the increase in cooling rate, it is suggested that an increase in precipitation strengthening due to refining of these precipitates by accelerated cooling more than offsets the loss of precipitation strengthening due to decreasing the precipitates fraction.
Prediction of the continuous cooling transformation diagram of some selected steels using artificial neural networks
Authors: Vermeulen Willem , van der Zwaag Sybrand , Morris Peter , de Weijer Ton 
Published: December 2016

Continuous cooling transformation (CCT) diagrams play an important role in the description of the transformation behaviour of steels. The experimental determination of a CCT diagram is a very time consuming and expensive task. It would therefore be very attractive to be able to predict CCT diagrams from the chemical composition of the steel and its austenitising temperature. In this article the use of artificial neural networks for the prediction of the transformation start and finish lines in CCT diagrams is described. The data were selected from a single source: The vanadium steels, atlas of continuous cooling transformation diagrams [4].Three neural networks with different numbers of hidden nodes (5‐10‐15) were trained. The number of hidden nodes did not significantly influence the accuracy in the prediction. The network with the least number of hidden nodes (5) was therefore chosen for the evaluation of the performance of the neural networks. This neural network was able to predict the general trends in the CCT diagrams quite well. The relative standard deviation in the prediction of start and end temperatures of each transformation depended on the cooling rate. For the high and low cooling rates it was ∼ 40°C, for the intermediate it rose to 90°C for the ferrite start formation and to 75°C for the other diffusional transformations (pearlite and bainite).The accuracy of the predicted CCT diagram was primarily restricted by the modest quality of the input data used to train the neural network.