bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
A feasibility study for the removal of copper from solid ferrous scrap
Authors: Iwase Masanori , Tokinori Kenji
Published: December 2016

A new approach for the removal of copper from solid ferrous scrap is described. With this proposal, solid ferrous scrap intermingled with copper is brought into contact with molten aluminium, which preferentially dissolves copper. After a duration of 5 to 10 minutes at a temperature of 1018 ± 5 K, steel scrap is removed from the bath, resulting in being free of copper contamination. The present method offers the advantage of far lower costs than any other processes ever suggested for copper removal.
Mathematical description of static recovery of type C–Mn–Mo–Nb–V microalloyed steel
Authors: Schindler Ivo , Kliber Jiři , Bořuta Josef
Published: December 2016

A new method of determining the softening ratio X was evaluated by comparing stress‐strain curves over the yield point. A widely executed experimental program on the computer‐controlled torsion plastometer allowed us to provide the mathematical description of the X‐value as a function of the deformation temperature T and time t between deformations, temperature of austenitization Ta, strain e and strain rate ∊̇ of the previous pass, respectively. The picture in words refers to a microalloyed steel base of C–Mn–Mo–Nb–V which is recovered in the temperature range from 700 to 900°C.
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.
Thin‐strip casting of steel with a twin‐roll caster – discussion of product defects of ≍ 1 mm‐Fe6%Si‐strips
Authors: Büchner Achim R. , Schmitz Johann Wilhelm
Published: December 2016

After a former detailed study of the thin strip casting process now defects of the strip and their avoidance are discussed. Hence it is deduced that the casting process should be carried out with small rolling forces. Thus the process of strip cooling has to be separated from the process of strip forming, and a cooling device has to be established close to the casting rolls.
Zur Modellierung der Verfestigung metallischer Werkstoffe unter zyklischer Belastung in der Umformtechnik
Authors: Ismar Heinz , Schmitt Joachim
Published: December 2016

In dieser Arbeit wird die Notwendigkeit eines weiterentwickelten Zweiflächenverfestigungsmodells auf der Grundlage des Übergangsfließpotentials für zyklische Plastizität am Beispiel der metallischen Werkstoffe AIMgSi1 und X 2 CrNi 18.9 dargelegt. Die Auswertung der experimentellen Ergebnisse zeigt eine ausgeprägte Entwicklung der Fließflächengeometrie, ferner der isotropen und der kinematischen Verfestigung.
Bainite morphologies in a 0.2 C–1.5 Mn steel
Authors: Joarder Asok , Sarma Darbha Subrahmanya
Published: December 2016

The isothermal transformation products of austenite over a wide range of temperatures and times in the bainitic range in a 0.2 wt.% C–1.5 wt.% Mn steel have been studied by transmission electron microscopy in order to characterise the bainitic microstructures in low‐carbon low‐alloy steels. Widmanstätten ferrite has formed with alternate layers of austenite (martensite) as a transition product at 600 and 500°C that has finally transformed on further isothermal transformation to either pearlite (at 600°C) or upper bainite (at 500°C). This type of transformation product was referred to as BI bainite by earlier investigators, but on the basis of the present investigation it is concluded that such ferrite‐austenite (martensite) structures are not bainitic as this is not the final transformation product either at 600 or 500°C. Both upper bainite and lath‐type lower bainite are formed at 450°C while the transformation product has been only lath‐type lower bainite at 400°C.
Some fundamental questions about R‐curves
Authors: Kolednik Otmar
Published: December 2016

With the help of two simple thought experiments it is demonstrated that there exist two physically different types of fracture toughness. The crack‐growth toughness, which is identical to the Griffith crack growth resistance, R, is a measure of the non‐reversible energy which is needed to produce an increment of new crack area. The size of R is reflected by the slopes of the R‐curves commonly used. So an increasing J‐Δa‐curve does not mean that the crack‐growth resistance increases. The fracture initiation toughness, Ji, is a normalized total energy (related to the ligament area) which must be put into the specimen up to fracture initiation. Only for ideally brittle materials R and Ji have equal sizes. For small‐scale yielding a relationship exists between R and Ji, so a one‐parameter description of fracture processes is applicable. For large‐scale yielding R and Ji are not strictly related and both parameters are necessary to describe the fracture process.
Transformation characteristic of a Cr‐Mn steel with austenite
Authors: Zylla Isabella M. , Hougardy Hans Paul
Published: December 2016

The microstructures of three steels with about 0.35% C, 10% Mn and 13% Cr were investigated. After homogenization treatment, all steels have an austenitic microstructure with some carbide precipitates. During cooling to −196°C as well as by plastic deformation ε‐martensite and α‐martensite are formed. The influence of the degree of deformation at different temperatures on microstructure and stability of austenite is described in detail. This information will be used to find a microstructure optimized to have a high cavitation resistance.
High‐speed temperature measurements during rapid solidification of iron‐silicon ribbons, produced by planar flow casting
Authors: Frommeyer Georg , Ludwig Andreas
Published: December 2016

In order to investigate the melt undercooling and the non‐equilibrium solidification of crystalline Fe 5 wt.% Si melt spun ribbons, produced by planar flow casting (PFC), high speed temperature measurements and appropriate process simulations have been performed. Using a rotating fibre optical system with a fast response double pyrometer, the temperature radiation of the solidifying ribbon during the casting process has been recorded with a measuring frequency of 50 kHz. The obtained cooling curves have been interpreted by computer simulations. It is shown that with increasing wheel temperature the overall cooling becomes more efficient. This is caused by an improved wetting behaviour of the melt‐wheel system and an increase in the heat transfer coefficient at the interface of the solidifying ribbon and the wheel from 6 · 104 to about 2 · 105 W/(m2K). The solidification of 100 to 200 μm thick ribbons takes place in a time interval of 2 to 5 ms. The average growth rate varies between 10 and 60 mm/s. The high cooling rate results in a fine dendritic solidification morphology with diminishing microsegregations.
Thermal behaviour of a moving steel strip cooled by an array of planar water jets
Authors: Filipovic J. , Viskanta Raymond , Incropera F. P. , Vesiocki T. A.
Published: December 2016

A mathematical model has been developed to predict the temperature distribution in a moving strip of steel cooled by an array of planar water jets. Experimentally determined nucleate boiling and analytically obtained single‐phase convection and film boiling heat transfer coefficients are used as convective boundary conditions, and thermophysical property variations of the steel with temperature are considered in the analysis. The model equation for the strip temperature distribution is solved numerically, and the model is validated by comparing predicted coiling temperatures with measurements obtained on the runout table of a steel mill.
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.
The influence of strain amplitude on the transient current behaviour in corrosion fatigue of Fe‐26Cr‐1Mo
Authors: Wang Jianqiu , Wang Zhongguang , Ma Minya , Zang Qisan , Zhu Zhiyong
Published: December 2016

Corrosion fatigue damage and its electrochemical characteristics of high purity ferritic stainless steel (Fe‐26Cr‐1Mo) under symmetrical tension and compression strain control have been investigated in 1M H2SO4 and 3.5 % NaCl solution by using three‐electrode technique at imposed passive potential. The tests were carried out at the total strain amplitudes of 4 × 10−3, 8 × 10−3, 1.0 × 10−2 and 1.2 × 10−2. The effects of the strain amplitude on the electrochemical dissolution and plastic deformation on the surface were studied particularly. At low strain amplitude (Δεt = 4 × 10−3), the passivity‐maintaining current was small and stable because of the small slip activity. The maximum current at the tensile half cycle, ltp, was always bigger than lcp, or sometimes equal to lcp, the maximum current at the compressive half cycle in 3.5 % NaCl. At high strain amplitude (Δεt = 1.2 × 10−2), the enhanced deformation on the surface induced the increasing dissolution. The increasing anodic current reflects the breakdown of the surface film, and only one current peak occurs within one cycle. At intermediate strain amplitude (Δεt = 8 × 10−3), the current behaviour was very stable after cyclic hardening in 3.5%, NaCl, but periodical jumpings of current during cycling were observed in the saturation region in 1 M H2SO4.
Investigations of the influence of titanium addition to the base material on toughness properties of the HAZ
Authors: Görss Herwart , Krebs Herbert , Dahl Winfried
Published: December 2016

Without taking precautions on the material side the application of fully mechanized welding techniques with high heat inputs into the base metal can lead to undesirable grain growth and unfavourable toughness values in the HAZ. The aim of the investigations of four fine grained steels (FeE 355) with varied contents of titanium and nitrogen and one steel without titanium addition was to study different states of precipitation in the steels, the change after a welding simulation treatment and the comparison with real weldments. The results have shown that in titanium microalloyed steels the increase of the austenitic grain size is clearly lower than in steels without titanium addition. They keep their favourable toughness properties even after welding processes with high heat inputs. The toughness values of the SA weldings are higher than the values of the simulated specimens.
Application of equilibrium investigations to operational practice of adjusting lowest phosphorus contents
Authors: Görl Ernst , Sardemann Klaus‐D. , Scheel Rüdiger
Published: December 2016

Operational investigations of dephosphorization in BOF were carried out. By means of a controlled slag steering during the entire blowing time in order to adjust a good fluid slag with low P2O5 content, saturated both with lime and lime silikates, a good approach to equilibrium state can be achieved. The thus incurred high expenditure, however, must be opposed to an appropriate expense profit ratio.
Sulfur distribution of low sulfur contents in steel melts
Authors: Fenzke Hans‐Werner
Published: December 2016

The report deals with investigations of the sulfur behaviour in the Fe–CaO‐Al2O3 – H2S‐H2 system at 1600°C and at very low values for the partial pressure of oxygen and sulfur. Results of the equilibrium in the iron‐gas system, of the sulfide and sulfur capacities, of the solubility and activity of CaS in CaO‐Al2O3 slags are represented.
Collision‐controlled growth of composites in casting nozzles
Authors: Fix Wolfdietrich , Jacobi Hatto , Wünnenberg Klaus
Published: December 2016

Like the open‐stream nozzles and submerged entry nozzles on c.c. tundishes, ladle nozzles can also become blocked. Accumulations of Al2O3, CaO · 2Al2O3, CaO · Al2O3, MgO · Al2O3 and Ti3O5 particles were observed on five sleeves removed from rotary ladle nozzles. The type of particles suspended in the steel depends on metallurgy. Growth takes place in bushy ramification in a coral‐shaped structure and is controlled by flow separation, interfacial turbulence and gradient collision. Heat transfer on the nozzle wall is impaired. Steel which has infiltrated freezes if a heat sink is present. A stable composite of steel and oxide is formed. CaS depositions in c.c. tundish submerged entry nozzles are also examined. These CaS deposits become coated with viscous aluminates of the (C12A7 + CA) type, prior, here too, to impregnation with steel. The overall result is a reduction in interfacial energy.
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.
The effect of calcium additions to aluminium containing flux on the mechanical properties of structural steel
Authors: El Gammal Tarek , Dahl Winfried , Zu Zhomgbo
Published: December 2016

The effect of treatment of plain carbon liquid steel with mixtures of CaO‐CaF2‐Al and CaO‐CaF2‐Al with calcium added either pure or as CaAl or CaC2 on steel quality has been investigated. Both mixtures reduce total oxygen and sulphur contents to low levels, improve inclusion morphology and increase toughness properties, but the improvement obtained with added calcium as CaAl or CaC2 is striking. Total oxygen and sulphur contents were reduced to below 5 ppm and 10 ppm, respectively, alumina and MnS inclusions completely transformed, anisotropy eliminated and the transition temperature lowered to below −60°C. The influence of oxygen and sulphur content, and of inclusion morphology, on the toughness properties of the steel has been demonstrated.
A study on the kinetics of iron oxide reduction by solid carbon
Authors: Bandyopadhyay Debajyoti , Chakraborti Nirupam , Ghosh Ahindra
Published: December 2016

Rate of reduction of ferric oxide in the presence of solid carbon was measured in the laboratory using a thermogravimetry setup. Iron oxide in the form of powder and micropellets were used. Coconut char of high reactivity was employed as carbonaceous material. Product gas analysis was carried out to calculate the rate of carbon loss during reduction. Ferric oxide reduction was found to take place in a stage‐wise manner. For the powder system, the overall reaction was found to be exclusively controlled by the gasification process. Gasification rates of coconut char in carbon dioxide were utilized to predict the rates of carbon loss during reduction. The predicted and experimental rates of carbon loss during reduction of ferric oxide by carbon were compared and possible explanations were given for the observed trends.
The applicability of an isokinetic steel feeding system for near‐net‐shape strip casting
Authors: Scholz Reinhard , Jeschar Rudolf , Matschullat Thomas , Urlau Ulrich , Reichelt Wolfgang
Published: December 2016

For the near‐net‐shape casting of thin steel strips a liquid steel feeding system is developed. This article at first describes the development of a water model for the complete casting machine (cold tests). In this model the control concept for the low‐pressure tundish is designed and tested. As a subsequent stage to the water model trials, the functional ability of the casting machine concepts, and particularly to the tundish concepts, is verified in separately conducted tundish tests and also in strip casting trials (hot tests).
Investigation of tungsten concentrate used for alloying in ladle refining process
Authors: Chen Weiqing , Zhou Rongzhang , Huh Wan‐Wook , Rhee Chang‐Hee
Published: December 2016

Direct alloying of steel with tungsten concentrate in an Ar‐stirred ladle was investigated in a laboratory scale. Kinetics of WO3 reduction in slag was analyzed according to the experimental results. Reduction of (WO3) by [Si] is the main reaction during direct alloying. The intensity of Ar stirring and [Si] content have great influence on the reduction rate of (WO3). Reduction of (WO3) is a second order reaction.
Influence of titanium content and grain size on hydrogen cracking behaviour of hot‐rolled steels
Authors: Valentini Renzo , Solina Adriano , Cramer Christian
Published: December 2016

Hydrogen induced cracking was investigated for hot‐rolled titanium steels. Aim of the present work was to observe the influence of titanium content and grain size on the cracking behaviour. Three titanium steels (0.12‐0.30 % Ti; O.0057‐0.0480 % C) and one non‐titanium steel (0.0056 % C) were used for the investigation. Various grain sizes were generated by heat treatment at 950, 1050 and 1150 °C; furnace cooling was applied. The specimens were electrolytically charged with hydrogen at various current densities. It was found that cracks are generated at low charging current densities for the investigated steels. The titanium steels showed better performance than the non‐titanium steel. It was shown that the charging current density does not correspond to the hydrogen concentration in a steel; the hydrogen concentration in steel B was 3.8 ppm at 1 mA/cm2, in steel D it was found to be 15.5 ppm at 0.5 mA/cm2. The total hydrogen concentration was found to be influenced by content of precipitates and grain size. It was shown that the percentage of cracked grain boundary area increases with increasing grain size. This increase is linear for the non‐titanium steel whilst for the titanium steels a plateau was observed at a grain size diameter of 50 μm.
New model describing creep of metallic materials under variable temperatures
Authors: Batsoulas Nikolaos D.
Published: December 2016

A creep function using only three fitting parameters is presented hereafter. The function is derived from a more general physical ‐ phe‐nomenoiogical model representing metallic materials creep behaviour and describes all three stages of creep. The dependence of the fitting parameters upon the temperature are investigated and simple analytical relations are provided for that purpose. Those relations already incorporate the effect of stress. At the outcome, ten material constants are derived which are neither dependent on the stress nor on the temperature. On the basis of the derived constitutive relations a prediction is carried out for creep strain of three metallic materials and particularly steels, at different temperatures and under constant stress. The derived curves agree with the experiments, not only the ones carried out in the laboratory but also the ones taken from literature.
Hot corrosion of Fe‐10Cr‐18Ni‐5Mn‐5Al‐Si‐N steels in molten sulfate deposits
Authors: Ghanem Wafaa Abd‐el‐Rahem
Published: December 2016

The effect of Na2SO4 coating on the corrosion behaviour of 5 steel alloys as well as two commercial alloys ‐ type 304 stainless steel and Inconel 690 ‐ were tested in air at 900 °C under atmospheric pressure. Corroded samples were analysed by XRD, SEM and EDX. A newly developed alloy (No. 5) having the composition Fe‐10.4Cr‐15.43Ni‐5.52Mn‐5.52AI‐1.5Si showed almost comparable corrosion resistance with Inconel 690. Stainless steel 304 failed catastrophically. Other newly developed alloys (no. 1‐4) showed intermediate resistance. The results have been interpreted in the light of the nature of scales formed and on the premise that Na2SO4 decomposes to give S2‐ ions which delay the formation of an internal protective film.
The influence of MgO, K2O, Na2O and gas pressure on slag foaming behaviour under reducing conditions
Authors: Ren Jinguo , Westholt Michael , Koch Klaus
Published: December 2016

Using a photoelectric measuring technique to determine the foaming behaviour of iron oxide‐containing slag, investigations were carried out into the influences of magnesium oxide and the alkali oxides K2O and Na2O on melt foaming behaviour under reducing conditions. An MgO content of just a few percent intensifies the foaming action of acidic and self‐fluxing melts. This behaviour is also induced by a relatively low addition of alkali oxide. If the magnesium oxide and alkali oxide addition is further increased, slag volume growth during foaming declines. With basic compositions, both the magnesium oxide and the alkali oxides may reduce the volume increase of the foaming slag. Overall, melts undergo maximum foaming under conditions of medium basicity and in the medium temperature range. Alkali oxides promote the phenomenon of melt resolidification often observed in the tests. Tests with different furnace gas pressures up to max. 3 bar reveal that foaming volume of the melt increases with rising gas pressures.
Simulation of the forming of mash seam welded sheets
Authors: Draugelates Ulrich , Bouaifi Belkacem , Sommer Dieter , Seibert Dominic
Published: December 2016

The paper presents results on the optimization of the process of mash seam welding for improving the formability of the joined sheet metal semi‐products. An integrated concept including the welding, smoothing and heat treatment of mash welded sheets has been developed. As an example, fatigue tests and the simulation of the forming behaviour of a mash seam welded tensile specimen simulated by the finite element method (FEM) is discussed. The determination of the material properties of the seam which, so far, have been determined experimentally is thus considerably simplified.
Assessment of intrinsic creep resistance evolution based on the results of constant load creep tests
Authors: Pantelakis Spiros G. , Vassilas Nikolaos I. , El‐Magd Essam A. , Rix Karl F.
Published: December 2016

In the present study a method to assess the intrinsic creep resistance evolution by using data of constant load creep tests is proposed. The investigation has been performed on the austenitic steels X6 CrNi 18 11 and X8 CrNiMoNb 16 16. To develop the constitutive equation describing the intrinsic creep resistance evolution a simple structural mechanical model has been used. The applied model is based on a modification of the Levy‐Mises equation for plasticity to consider creep time effects. The proposed model has been verified experimentally. The experimental creep resistance evolution curves have been derived with the aid of strain transient dip test performed in transient, steady state and accelerated creep stage.
Numerical simulation of temperature distribution and solidification behaviour during spray forming
Authors: Fritsching Udo , Zhang Hong , Bauckhage Klaus
Published: December 2016

A mathematical, two‐dimensional model for the analysis of the temperature and solidification behaviour in the substrate and deposit for the spray forming process of metals has been developed. Due to the irregular shape of the growing deposit, which changes with spraying time, a grid transformation method was successfully developed for the calculation of the temperature distribution and solidification front in the growing deposit. The influence of process parameters, i.e. thermal conditions of the metal spray at impact, heat transfer coefficient at the surface of the deposit and geometrical parameters, are qualitatively and quantitatively discussed.
Development of new methods for determining the formability and flow stress of materials based on intermetallic compounds
Authors: Pawelski Oskar , Hagedorn Karl Edgar , Hop René
Published: December 2016

The following test methods were developed: the small‐cup tension test, the mantle compression test, and the ball compression test. They are applicable up to very high temperatures. The experiments with model materials and NiAl‐ and TiAl‐compounds were combined with plastomechanical calculations by the method of upper bound of deformation power and by the method of finite elements.
On the bainite structure in Cr‐Mo‐V rotor steel
Authors: Joarder Asok
Published: December 2016

The morphology of continuously cooled and isothermally transformed bainite structures formed in a Cr‐Mo‐V rotor steel has been studied using transmission electron microscopy. The samples were austenitised at 955°C for an hour followed by air cooling to room temperature. The isothermal transformation reaction was carried out at 450°C for up to 100 000 s. The microconstituents observed are predominantly lower bainite with very small amount of upper bainite and martensite (formed from untransformed austenite due to water quenching). Analysis of the selected area diffraction patterns confirm that the carbide in bainite is orthorhombic cementite and the orientation relationship between ferrite and cementite is consistent with that of Bagaryatskii. The carbide particles in isothermally transformed bainite are coarser than those of continuously cooled bainite. Tempering one hour at 670°C of continuously cooled steel samples exhibited formation of fine spheroidal MC type carbides. In addition tempering leads to the enrichment of prior austenite grain boundaries by cementite particles. Tempering ten hours at 670°C exhibited microstructures almost identical to those observed in one hour tempering.
Thermodynamic activities of FeO in CaO‐FeO‐SiO2 slags
Authors: Bygdén Johan , Sichert Du , Seetharaman Seshadri
Published: December 2016

In the present work, a thermodynamic model to describe the activities of components in complex slag systems based on a Temkin approach has been put forward. The model was applied to the ternary system CaO‐“FeO”‐SiO2 in order to calculate the activities of FeO as a function of temperature and composition from literature data. For this purpose, the experimental data on the activity of FeO available in literature were complemented in the present work by ZrO2‐CaO solid electrolyte galvanic cell measurements for some selected compositions. An assessment of the data for the binary systems FeO‐SiO2 and CaO‐FeO was carried out. The computed ternary activities are presented in the form of iso‐activity lines at 1673 and 1873K. On the basis of the model predictions, the reliability of the solid electrolyte method for such measurements is discussed.
Evaluation of abrasive‐wear and erosion‐corrosion resistance of high‐Cr cast‐steel
Authors: Metwally W. A. , Samy M. K.
Published: December 2016

In order to evaluate the performance of high‐Cr cast‐steel (15.4% Cr), as a pump casing material, abrasive wear, hardness, corrosion, erosion‐corrosion resistance were examined and compared with grey cast iron eventually used. The results obtained were analyzed on a microstructural basis with respect to Cr content of the matrix, amount and types of carbides and the extent of surface passivation. Martensitic high‐Cr steel has shown a better performance than grey cast iron.
Adaptive neural net (ANN) models for desulphurization of hot metal and steel
Authors: Datta Amlan , Hareesh Mavoori , Kalra Prem Kumar , Deo Brahma , Boom Rob
Published: December 2016

Neural nets can be adapted to complex patterns of interrelated input and output variables in a process even if the data sets contain a lot of noise. In this work two specific examples for the application of adaptive neural nets (ANN) in steel Industry are described. First, the sulphur content of hot‐metal, obtained at the end of calcium carbide powder injection into 4001 torpedo ladles is predicted as a function of hot‐metal weight, treatment time, initial sulphur content, gas flow rate and powder injection rate. The values predicted by the trained ANN model for a completely new set of input test data compare well with the actual values obtained on the shop floor. In the second example, the sulphur content of steel, obtained at the end of blow is predicted as a function of liquid‐metal weight, total amount of oxygen injected, amount of iron ore added, and the temperature, contents of carbon, manganese, phosphorus and sulphur determined by in‐blow sampling in a 300 t converter. The ANN predicted values of sulphur content of steel at tap (without reblow) also agree well with the values obtained on the shop floor.
Optimization of a BOF's lining resistance by application of artificial neural network
Authors: Cai Yudong
Published: December 2016

The artificial neural network approach for optimization of lining resistance of basic oxygen furnace is presented in this paper. A group of samples has been collected to study. 33 samples are divided into two classes, i.e. good samples (class 1) providing a furnace life of more than 1000 heats, and bad samples (class 2) meaning a furnace life of less than 1000 heats. Analysis of 18 factors influencing furnace life shows that the major factors are supplementary filling amount, blowing time, melting time, and production rate. In this research, 25 samples are used as learning material, while eight samples are used as testing material for the natural network. The factors of major influence are taken as input variables. As a result, the testing rate reaches 100 %, which indicates that the model trained is reliable. In order to increase the furnace life according to the model, the partial derivative value of the output to each feature variable at the average point of class‐2 samples was calculated. The results show, that, whereas blowing and melting time had to be decreased, both the supplementary filling amount and production rate had to be increased. This result is quite consistent with the practical experience obtained in the plant. In addition, the neural network approach also has a fault‐tolerant ability, prediction and optimization speed. To sum up, the neural network approach might be referred to as an effective assistant technique for optimization of iron and steel industry.
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-0001

The heat of reaction:

urn:x-wiley:01774832:srin01094:equation:srin01094-math-0002

was estimated to be −1107 kJ/mole.
Influence of post weld heat treatment on impact toughness properties of 1Cr0.5Mo and 2.25Cr1Mo steels
Authors: Storesund Jan , Sandström Rolf
Published: December 2016

The influence of post weld heat treatment on hardness and impact toughness properties of weldments of 1Cr0.5Mo and 2.25Cr1Mo steels has been investigated. Post weld heat treatment significantly reduced the hardness and the impact transition temperature and increased the upper shelf energy. The decrease in hardness was essentially larger for 2.25Cr1Mo than for the other steel, probably due to the presence of martensite in the as‐welded condition in the former material. The decrease in the impact transition temperature was largest for 1Cr0.5Mo.
Stereological alterations of non‐metallic inclusions, fracture morphology and alloy impact strength after blowing active powders into liquid steel
Authors: Cybo Jerzy
Published: December 2016

Reported here is an analysis of effectiveness of the process of steel refining by the method of injecting active powders. Apart from a brief assessment of the technological aspect, attention is focused principally on changes in morphology and stereological characteristics of the nonmetallic inclusions (NMI). As a result, there are the only appreciable changes due to this refining process. Since, as a consequence, the impact strength of the material is considerably enhanced, the curve of alloy transition to the brittle state is defined by means of parameters describing the set of inclusions. The model obtained in this way describes change in plastic properties against numerical characteristics of the nonmetallic phase for any arbitrary temperature. This enables a quantitative assessment to be made of such refining effects as reduction in number and size of inclusions and differentiation in size of these particles. The consequences of these changes are, respectively: linear improvement in impact strength with temperature increase; exponential rise in impact strength, particularly during work at low temperatures; slowed rate of impact strength decrease at positive temperatures, and increase at low temperatures. The analytical description presented can be an effective tool both for quantitative evaluation of steel refining results and for analysis of the role of NMI in the decohesion process.
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 contribution to the theoretical description of metal‐slag reaction kinetics
Authors: Oeters Franz , Xie Hui
Published: December 2016

In this paper the main aspects of a theoretical model of mass transfer through liquid‐liquid interfaces under non‐turbulent flow conditions are described. The model is based on the general boundary layer theory of momentum and mass transfer. Expressions for calculation of the mass transfer coefficients on the metal and slag side of the phase boudary are presented. It is shown that the model comprises as limiting cases the mass transfer through free surfaces and at solid walls.
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-0001

where ΔG0 is the standard Gibbs energy change for the reaction,

urn:x-wiley:01774832:srin01155:equation:srin01155-math-0002

ξ, 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.
Kinetics of mass transfer of manganese and silicon between liquid iron and slags
Authors: Xie Hui , Oeters Franz
Published: December 2016

The kinetics of mass transfer of Mn and Si between liquid iron and slags were investigated in laboratory experiments at 1600°C in MgO crucibles with 1500 g iron and 250 g slag. Three different slags consisting of CaO‐MgO‐MnO‐SiO2, MgO‐MnO‐SiO2 and MgO‐MnO‐Al2O3‐SiO2 were used. The concentration‐vs.‐time curves, experimentally measured under defined flow conditions generated by gas stirring, were evaluated by application of a multi‐component transport model in order to obtain the mass transfer coefficients. The numerical values of the thus determined measured mass transfer coefficients were compared with values calculated by a theory of mass transfer at liquid‐liquid interfaces. The measured and theoretical values were in good agreement with each other in the case of reduction of MnO from the slag by Si in the metal, provided that the measurements had been carried out below a critical stirring intensity, above which metal droplets were emulsified in the slag. Experiments, where sulphur was dissolved in the metal melt and where the sulphur contents were systematically varied, showed no changes of the mass transfer coefficient in comparison to sulphur‐free melts. The experimental mass transfer coefficients for the reduction of silica from the slag by manganese in the metal were smaller than those calculated by the mentioned mass transfer theory. This could be explained by inhibition of surface renewal under the influence of solid reaction products precipitated at the interface.
Spectral interference of polyatomic ions of Cr, Fe, Mn, Mo, Ni, and W in steel using inductively coupled plasma mass spectrometry
Authors: Kuss Heinz‐Martin , Müller Martin
Published: December 2016

Because of the low resolution of quadrupole mass filter, polyatomic ions interfere with analyte ions in inductively coupled plasma mass spectrometry. In order to achieve accurate results it is urgently recommended to know the kind and the amount of ions of the major concentrated elements of the sample. The matrix elements of high purity iron, low, and high alloy steels are Fe, Cr, Ni, Mn, Mo, and W. 175 different polyatomic ions of the matrix elements and those of nitric, hydrochloric, and hydrofluoric acid are experimentally determined in steel sample solutions. Signal intensities higher than a threshold of 30 counts/s have been considered as significant. 100 isotopes of 25 elements show interference at 69 m/z‐values.
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.
Interpretation of probe temperatures in the blast furnace using polynomial approximations
Authors: Saxén Henrik
Published: December 2016

This paper describes a method for interpretation of temperature distributions measured by an above‐burden probe in a blast furnace. The distributions are approximated by polynomials, based on which indices are computed and depicted graphically in order to track the evolution of the gas distribution in the shaft. Using the indices, both gradual and abrupt (spontaneous) changes in the gas flow patterns have been detected. The indices can also be used to verify whether burden distribution control actions have led to desired results, and to detect imbalance in the gas flow.
Solubilities of carbon in CaO‐Al2O3‐SiO2 slags saturated with liquid iron
Authors: Lee Kwang Ro , Suito Hideaki
Published: December 2016

By equilibrating the CaO‐Al2O3‐SiO2 slags with Fe ‐ 0.0003∼0.07% Al ‐ 0.002∼3.5% Si ‐ 0.9∼2.0% C alloys (mass contents in %) at 1873 K, the solubilities of carbon were measured as a function of Si contents in metal, using an alumina or lime crucible. The distribution ratios of carbon as a C2‐ ‐ion were found to be linearly related to Si contents with a slope of 1/2 at a given slag composition. The carbide capacity, , defined by (% C) , increased with increasing SiO2 contents at a given CaO/AlO1.5 molar ratio in the CaO‐AlO1.5SiO2 system.
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.
Creep equations for high temperature alloys on the basis of a parametric assessment of multi‐heat data
Authors: Kloos Karl Heinz , Granacher Joachim , Pfenning Andreas
Published: December 2016

For the design of high temperature components creep equations are necessary. These describe the deformation behaviour of the material type used over its whole application range. The method of developing such an equation is demonstrated for the example of alloy G‐NiCo 15 Cr 10 Al 6 TiMo (Alloy 100). As a basic requirement, a multi‐heat assessment of time to specific strain is performed with the aid of a time temperature parameter procedure. In this way optimum correlated master curves are generated for the whole range of permanent strain and rupture. From these curves mean creep curves for the material type can be determined by minimal further smoothing. On the basis of these creep curves a modified Garofalo equation with initial plastic strain as well as primary, secondary and tertiary strain can be established to describe the creep behaviour of Alloy 100. Additionally, an equation for the time temperature dependent contraction of this alloy can be developed. These equations form a useful tool for the calculation of high temperature components with the finite element method.