bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Single‐Belt Strip Casting Simulator
Authors: Nogami Hiroshi , Netto Pedro G. Q. , Guthrie Roderick I. L.
Published: December 2016

Near‐net‐shape casting is one of the key technologies to improve process efficiency of steel production. Single‐belt strip casting is recognized as a promising technology for thin strip production because of the advantages like well‐controlled heat transfer rate, flexibility in production rate, compactness of equipment, and so on. In this study a newly designed simulator of the single‐belt strip casting process was developed. The simulator solidifies molten metal on the running solid metal bar with a groove for molten metal deposition pushed by a pneumatic cylinder. Capability of this simulator design was discussed by one‐dimensional numerical heat transfer analysis. It showed that a steel casting bar thicker than 40 mm was capable of casting test of 10 mm thick steel strip even if interfacial thermal resistance existed. Finally, the simulator was applied to the casting test of aluminum strip, and successfully estimated the variation of the interfacial heat flux from the solidifying strip to the casting bar.
The Activities of FexO in {CaO‐SiO2‐Al2O3‐MgO‐FexO} Slags at 1723 K
Authors: Kishimoto T. , Hasegawa M. , Ohnuki K. , Sawai T. , Iwase M.
Published: December 2016

In Japanese steelworks, hot metal is now produced by scrap melting process. With this process removal of sulphur is very much handicapped because of very high sulphur levels (0.04 to 0.09 pct by weight) and relatively low tapping temperatures (1623 to 1723 K). In order to overcome such disadvantages, the authors explored on the phase diagrams of {CaO‐SiO2‐Al2O3‐MgO} slags, and this research revealed that those slags at 35 wt%‐Al2O3 would be good candidates as reagents for the removal of sulphur from high sulphur hot metal at relatively low temperatures. For better understanding of the thermodynamic properties of the candidate slags, in this study, activities of FexO were determined by using solid‐state electrochemical cells incorporating MgO‐stabilized zirconia and Mo + MoO2 reference electrode.
The Dissolution of Alumina in CaO‐SiO2‐Al2O3 Slags
Authors: Monaghan Brian J. , Chen Liang
Published: December 2016

The dissolution of alumina inclusions in CaO‐SiO2‐Al2O3 based slags have been measured using laser scanning confocal microscopy (LSCM). Experiments were carried out over a temperature range of 1477 to 1577°C. It was found that diffusion coefficients calculated from the experimental results showed a dependence on the slag viscosity. This is considered strong evidence that the dissolution process is at least in part controlled by mass transfer in the slag phase. The diffusion coefficients for the alumina particles are estimated to be in the range 10−11 to 10−10 m2/s.
Preliminary Investigation of Fluid Mixing Characteristics during Side and Top Combined Blowing AOD Refining Process of Stainless Steel
Authors: Wei Ji‐He , Zhu Hong‐Li , Yan Sen‐Long , Wang Xin‐Chao , Ma Jin‐Chang , Shi Guo‐Min , Jiang Qing‐Yan , Chi He‐Bing , Che Li‐Bing , Zhang Kai
Published: December 2016

The fluid mixing characteristics in the bath during the side and top combined blowing AOD (argon‐oxygen decarburization) refining process of stainless steel were preliminarily investigated on a water model unit of a 120 t AOD converter. The geometric similarity ratio between the model and its prototype (including the side tuyeres and the top lances) was 1:4. On the basis of the theoretical calculations for the parameters of the gas streams in the side tuyeres and the top lances, the gas blowing rates used for the model were more reasonably determined. The influence of the tuyere number and position arrangement, and the gas flow rates for side and top blowing on the characteristics was examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during gas blowing, without obvious dead zone in the bath, resulting in a high mixing effectiveness. The gas flow rate of the main tuyere had a governing role on the characteristics, a suitable increase in the gas flow rate of the subtuyere could improve mixing efficiency, and the gas jet from the top lance made the mixing time prolong. Corresponding to the oxygen top blowing rate specified by the technology, a roughly equivalent and good mixing effectiveness could be reached by using six side tuyeres with an angle of 27 degrees between each tuyere, and five side tuyeres with an angular separation of 22.5 or 27 degrees between each tuyere. The relationships of the mixing time with the gas blowing rates of main‐tuyeres and sub‐tuyeres and top lance, the angle between each tuyere, and the tuyere number were evaluated.
Effect of Quench and Interpass Time on Dynamic and Static Softening during Hot Rolling
Authors: Jonas John J.
Published: December 2016

The categories of interpass time encountered in hot rolling are characterized. These are shown to fall into three broad categories: short (in rod rolling); intermediate (in strip processing); and long (in plate schedules). The effects of interpass time on recrystallization and carbonitride precipitation are described, and particularly on the interaction between these two mechanisms. The interactions, in turn, determine the final microstructure produced as well as the mechanical properties.
Metallurgical Development in Steel‐plant‐internal Multi‐injection Hot Metal Desulphurisation
Authors: Ender Alfred , van den Boom Heinz , Kwast Hartmut , Lindenberg Hans‐Ulrich
Published: December 2016

The use of thermodynamic, statistical, and light and electron‐optical microscopic methods has made it possible to analyse the course of reactions during steel‐plant‐internal hot metal desulphurisation. The theoretical dependence between oxygen and sulphur activity has been used to develop an EMF‐measurement‐based technique for determining the sulphur content as the hot metal is desulphurised. The absence of magnesium sulphide from the collection of phases in the final slag because of the greater stability and secondary formation of calcium sulphide has been explained with the aid of thermo‐chemical calculations.
Off‐gas Treatment in De‐chlorination Process of PVC
Authors: Long Shigang , Ma Chunxia , Wang Zhiquan , Meng Qingmin , Feng Xinhua , Mao Ming , Cao Feng
Published: December 2016

Waste polyvinyl chloride (PVC), which is used as oil substitute in blast furnaces, contains a large amount of chlorine. In the case of pyrolyzing PVC, it produces hydrochloric gas (HCl) which can damage plant equipment and pollute the environment. Hence it must be de‐chlorinated before it is injected into the blast furnace. This paper studied the treatment of off gas in the de‐chlorination process of PVC, and its influence on the environment. The results showed that a multi‐stage absorption system for HCl could recover up to 10% of the hydrochloric acid, which could then be used directly in galvanizing processes. It also reduced the emission of HCl to 0.0066 ~ 0.0068 mg/m3, which is far less than the 0.030 mg/m3 allowed by the national environmental standard [1].
The Combustion Efficiencies of the Waste Plastics as Supplemental Fuel for Blast Furnace
Authors: Cao Feng , Long Shigang , Luo Zhiguo
Published: December 2016

The possibility of using waste plastics as a source of secondary fuel in the blast furnace has been of interest recently. In order to study the feasibility of injecting waste plastics into blast furnaces, the paper compares the combustibility of several kinds of waste plastics with that of pulverized coal. To improve the combustion efficiency of waste plastics in the blast furnace, the effects of plastic particle size, blast furnace temperature and different atmosphere were investigated in the laboratory. The result shows that compared with pulverized coal, waste plastics have lower thermal ignition temperature, shorter burning time, higher burning rate, lower ash ratio and higher calorific values, which are beneficial for blast furnace injection. With the increase of both the blast temperature and the level of oxygen enrichment, as well as the decrease in the particle size of waste plastics, the combustibility of waste plastics can be improved immensely. The optimization of blast furnace injection utilizing recycled plastics as a source of secondary fuel is possible by considering all these variables.
Physical Simulation of Powder Injection Process in a Torpedo‐car
Authors: Luo Zhiguo , Zou Zongshu , Hou Qinfu , Ou Jianping
Published: December 2016

Through systematical physical simulation of powder injection process in a torpedo‐car, the influences of operation parameters on process variables such as uniform mixing time, powder penetration ratio and residence time are determined. The relationships between the operation parameters and the process variable are obtained using linear regression method. Finally, the optimum operation parameters for powder injection are found using multi‐objective nonlinear programming method.
Numerical Simulation of Nonmetallic Inclusions Behaviour in Gas‐Stirred Ladles
Authors: Zhu Miaoyong , Zheng Shuguo , Huang Zongze , Gu Wenping
Published: December 2016

The secondary refining of molten steel in gas‐stirred ladle has played a more and more important role in the production of high quality steel. In the present work, a mathematical model of the fluid flow and inclusions behaviour in a 150t gas‐stirred ladle was presented, and the variations in concentration, size and density for non‐metallic inclusions in the ladle during the refining process were predicted. The results show that during the refining process, the variations in the number density of the inclusions differed depending on size. The inclusions with a diameter less than 25 μm decrease during the whole period, while inclusions with diameter larger than 25 μm increase in the first stage of the treatment and gradually decrease during the later stage. After 15 minutes, all inclusions show a tendency to decrease, but the removal rate for inclusions of smaller size becomes slower. After treatment in the ladle, inclusions with a diameter larger than 50 μm were removed, the number of inclusions with a size between 30‐40 μm was not high, while inclusions that were smaller than 25 μm still remained in the molten steel. Two‐jet bubbling demonstrated an advantage over one‐jet for inclusion removal. The practice of bubbling argon with a higher gas flowrate initially, followed by a lower flowrate in the ladle was found to be beneficial for inclusions removal.
The Thermodynamic Properties of Fe‐Mn‐C Melt at Reduced Pressure
Authors: Wang Haichuan , Wang Shijun , Zhou Yun , Gao Li , Dong Yuanchi , Sun Haiping
Published: December 2016

The solubility of carbon in the Fe‐Mn‐C system was measured under reduced pressure of 1 Pa at 1573 K and 1673 K, respectively. The carbon solubility in terms of mole fraction in the iron based solution was found varying with manganese mole fraction in the solution and with temperature, as xC= 0.1819 + 0.2531 xMn at 1573 K and xC = 0.1981 + 0.2515xMn at 1673K. Manganese has a stronger influence on the carbon solubility at lower pressure than it has at higher pressure. The pressure was found to have an insignificant effect on the carbon solubility when manganese in the melt was absent.

The activity interaction parameters between manganese and carbon in the alloy were determined from carbon solubilities at 1573 and 1673 K. Analysis of the experimental results showed that under vacuum conditions, the activity interaction parameter of manganese with carbon is higher than that at atmospheric pressure.
The Investigation on the Microstructure of Metallurgical Molten Slags and the Foundation of the Primary Cluster Theory
Authors: Jiang Guo Chang , Wu Yong Quan , You Jing Lin , Chen Hui , Xu Kuang Di
Published: December 2016

This paper presents the characteristics of the properties of metallurgical molten slags based on the bond structure or the existence of certain ion clusters. Some experimental and theoretical approaches were adopted in the investigation. Two sets of high temperature Raman spectroscopy (HTRS) were established at Shanghai University; both can be successfully operated at 2000K or higher. One of them combines the accumulated time resolution together with the spatial resolution, and it is designed for both ultraviolet (UV) and visible (VIS) light. The SiOT model uses 5 kinds of Si‐O tetrahedra (Qn) as microsturctural units. In this model, each sample contains 250000 or more tetrahedra. The calculation using a GF matrix and electro‐optical parameter (EOP) methods were performed for every tetrahedron one by one to determine the partial Raman spectra of Qn. Then the spectra were integrated to obtain an envelope of the sample. In addition to the SiOT model, a CEMS model was also developed to link the ion cluster structure and the thermodynamic properties at equilibrium (as mixing free energy).
Fluid Flow, Heat Transfer and Inclusion Motion in a Four‐Strand Billet Continuous Casting Tundish
Authors: Zhang Lifeng
Published: December 2016

Inclusions in the steel in a four‐strand continuous casting tundish, billet and wire products are firstly investigated with industrial trials, and the fraction of inclusions removed in terms of total oxygen in the tundish is measured. Then the 3‐dimenional fluid flow, heat transfer and inclusion motion in the tundish are numerically simulated. The κ‐∊ two‐equation model is used to model turbulence. Inclusion motion and trajectories are calculated by considering drag force and buoyancy force, coupling the effect of turbulent fluctuation (Random Walk Model). The effect of strands‐blocking on the fluid flow, heat transfer and inclusion removal is studied. A new design of tundish is proposed focusing on removing more inclusions from the molten steel.
Effect of Through‐Thickness Macro and Micro‐Texture Gradients on Ridging of 17%Cr Ferritic Stainless Steel Sheet
Authors: Huh Moo‐Young , Lee Jae‐Hyup , Park Soo Ho , Engler Olaf , Raabe Dierk
Published: December 2016

In order to study the formation of ridging in ferritic stainless steel (FSS) sheets, the evolution of the crystallographic texture was investigated by macro and micro‐texture measurements throughout the thickness of the sheets. The as‐received hot band material displayed a pronounced through‐thickness texture gradient with a strong rotated cube orientation in the sheet center layer. The initial texture of the hot band had a high impact on the formation of the cold rolling texture and on the final recrystallization texture. Modification of the cold rolling texture by means of cross‐rolling led to an improvement of the macro and micro‐textures after final recrystallization annealing, which gave rise to an enhanced sheet formability in FSS. Tensile tests of specimens with half thickness revealed that ridging formed in the sheet center was much stronger than that in the surface. This observation was attributed to the more frequent formation of orientation colonies in the sheet center when compared to the sheet surface.
Inverse Analysis of Tensile Tests
Authors: Szeliga Danuta , Gawad Jerzy , Pietrzyk Maciej , Kuziak Roman
Published: December 2016

Application of the inverse analysis to the interpretation of hot tensile tests is the main objective of the work. Tensile tests were performed for carbon‐manganese steel samples at 1000°C and at three ram velocities. The measured temperature distribution was used as boundary condition in the finite element model of the direct problem. Recorded loads and elongation of the sample were used as input for the inverse analysis. The flow stress, recalculated for isothermal conditions and constant strain rate deformation, was determined as a function of strain up to the maximum deformations achieved in the neck. Validation of the flow stress model based on comparison of the measured loads with the finite element predictions for the developed Theological model, confirmed reasonably good accuracy of the procedure. Additionally, sensitivity of the measured parameters (loads and radius of the neck at certain elongation) with respect to the rheological parameters has been performed.
Effect of Cold Deformation and Multiphase Treatment Conditions on Low‐Carbon, Low‐Silicon Multiphase Steel
Authors: El‐Din Hoda Nasr
Published: December 2016

This paper presents multiphase (MP) treatments of a low‐C, low‐Si cold rolled steel. Despite the much lower content of Si compared to a typical TRIP steel, up to about 8 pct of retained austenite (γr) with 1.2 % carbon content can be obtained. Increasing prior cold deformation (i.e. decrease of parent austenite grain size) accelerates the transformation to bainite resulting in a decrease of the volume fraction of residual austenite (γr + martensite). Tensile strength of MP steel intercritically annealed at high temperature increases with higher cold reduction degree due to the smaller grain size of the present phases. On the contrary, the ductility and strength‐ductility balance deteriorate because the banded structure becomes more pronounced and the γr volume fraction diminishes. Decreasing intercritical annealing temperature results in an increasing γr fraction and a uniform distribution of second phases. Hence, the ductility and strength‐ductility balance are improved. Crystallographic preferred orientation is evident in the ferrite and martensite and its extent increases with higher cold deformation.
Selective Oxidation and Surface Segregation in High Strength Steels during Short Term Annealing in H2‐N2 ‐ Influence of B on Surface Chemistry
Authors: Parezanović Ivana , Spiegel Michael
Published: December 2016

In order to achieve appropriate mechanical properties, new high strength steels aimed for the car industry have to be alloyed with solution strengthening elements. The annealing treatment undergone on cold rolled sheets induces the selective oxidation of alloying elements such as Al, Mn, Si and Cr. The formed oxides exhibit a poor wetting by the Zn bath during hot dip galvanising, thus deteriorating the properties of the zinc coating. While surface‐segregating elements get oxidised, they interact with each other through the formation of spinels and/or mixed oxides during annealing and oxides which have a deleterious effect on wetting can be formed. The formation of (Mn, B) oxide was observed on alloys containing even very small amounts of B and this oxide is almost not wetted at all by Zn. Boron is added to interstitial‐free steels to improve the cold work embrittlement, by replacing phosphorus at the grain boundaries. In this paper, the selective oxidation of steels with and without B, in 5 vol. % H2‐N2 atmosphere at 820°C and different dew points was investigated. We found a very strong effect of segregation and oxidation of B on Si and S segregation and oxidation behaviour.
Effect of Selenium on Supersaturation in Aluminium Deoxidized Molten Iron
Authors: Tanabe Jun
Published: December 2016

The effect of selenium addition on supersaturation observed in aluminium deoxidized molten iron was studied at 1873K, by using Fe‐Al alloys and CaO‐Al2O3 slags in an alumina crucible. Selenium mass content was varied from 0.0005 to 1.81%. In experiments where the samples were rapidly quenched, the contents of supersaturated oxygen for given aluminium levels were not influenced by the addition of selenium. However, the effect of selenium addition on supersaturation was observed for mass contents of more than 0.009% selenium. The selenium distribution ratio between liquid iron and CaO‐Al2O3 slags was determined as a function of the aluminium content of the melt.
Effects of Anisotropy in Drawing and Extrusion Processes of Bulk Metal Forming
Authors: Pöhlandt Klaus , Lange Kurt , Zucko Mishel
Published: December 2016

The effects of anisotropy of axisymmetric materials (round bars, tubes) on metal forming processes are discussed. These effects are strongest for thin‐walled hollow materials in metal forming processes when the wall thickness is not predetermined by the die (tube drawing without mandrel, free extrusion of hollow components). Similarly to the normal anisotropy of sheet metal, a high radial anisotropy increases the resistance against a variation of wall thickness in tube drawing. There are also effects in forming solid materials such as forward extrusion of bars whereby the buckling of cross sections is influenced through the variation of radial anisotropy with the distance from the axis. The favourable anisotropy properties depend on the actual priorities. If, for example, for a metal forming process the material anisotropy results in high compressive stresses this may be favourable for increasing the ductility of the material whereas the increase of the load acting on the tool reduces tool life.
Hot Mechanical Properties of 24Cr‐14Ni High Alloy Billets
Authors: Lin D.‐Y. , Su S.‐A. , Chang T.‐C. , Chen Y.‐F.
Published: December 2016

24Cr‐14Ni alloys have gained importance in high temperature applications. Because of δ‐ferrite and α phase formation, 24Cr‐14Ni austenitic stainless steel billets are difficult to hot work. The mechanical properties at high temperature of such stainless steels are investigated on a hot tensile test machine according to hot‐rolling conditions, under different time and temperature regimes. These 24Cr‐14Ni stainless steels were also hot rolled under various reduction ratios. The influences of the reduction ratio on the hot mechanical properties and phase transformation from δ‐ferrite into σ phase in 24Cr‐14Ni stainless steels are discussed in detail. The results obtained can be a contribution to improve the hot rolling of this high alloy stainless steel.
Carbon Solubility and Phase Composition of Silicomanganese
Authors: Anacleto Nathaniel , Ostrovski Oleg , Ganguly Samir
Published: December 2016

This paper examines silicomanganese produced in the electric ferroalloy furnaces at Tasmanian Electrometallurgical Company (TEMCO). Its carbon solubility and the phase composition were determined. Silicon content is the major factor affecting carbon concentration. Temperature also plays an important role in the carbon concentration. Silicomanganese consists of three phases: the silicides (Mn,Fe)5Si3 with approximately 0.7 wt% dissolved carbon and (Mn,Fe)3Si with a carbon content of 0 ‐ 0.6 wt%, and carbide (Mn,Fe)17Si4C3 with 3.3 wt% C. The fraction of carbide phase increased directly with increasing total carbon in the alloy. Silicon carbide was not detected. Reasonable estimates of carbon content are possible using the carbon‐silicon equilibrium relationship to the SiMn production process of TEMCO.
Extraction of Zinc‐Cobalt from Sulphate Solution of Cobalt Cake by D2EHPA in the Processing of Indian Ocean Nodules
Authors: Kumar Vinay , Bagchi Dulal , Pandey Banshi D.
Published: December 2016

During the processing of Indian ocean nodules, cobalt cake containing zinc in equal proportion is produced. In order to get pure cobalt and zinc from the sulphate leach solution of cake, a solvent extraction process has been considered using an organic extractant, di‐(2‐ethylhexyl) phosphoric acid (D2EHPA). Separation of cobalt and zinc has been carried out by mixing aqueous and organic phases in a rectangular vessel and separating the phases after equilibration in a glass funnel. The analysis of the metal from the aqueous phase was made by atomic absorption spectrometer to compute the metal transfer. The extraction and separation studies carried out under the different operating conditions indicated favourable zinc extraction at the lower pH (~ 2) with partially saponified D2EHPA. The small amount of cobalt co‐extracted with zinc was scrubbed with dilute sulphuric acid. With completely saponified D2EHPA, a high degree of cobalt extraction (99.8%) was achieved at aqueous feed pH of 5.0. The flow sheet developed could be used for the selective extraction and separation of zinc and cobalt from the leach liquor of cobalt cake.
Reduction Behaviour of BOF type Slags by Solid Carbon
Authors: Jung Sung‐Mo , Do Young‐Ju , Choi Ju‐Han
Published: December 2016

Experiments were carried out on a system with artificially prepared slags in a graphite crucible, in order to examine the possibility of recycling BOF slags produced in the steelmaking process. More than 80% of FeO and P2O5 was reduced within 20 minutes and the FeO reduction rate was greater than that of P2O5. P2O5 reduction began after more than 60% of FeO was reduced. Increasing slag basicity enhanced the reduction of FeO and P2O5. Temperature also improved slag reduction. The overall reduction rate was controlled by the chemical reaction at the slag/carbon interface. The reduction rates of FeO and P2O5 were second and first order with respect to their respective contents. Most of the reduced phosphorus is believed to vaporize in the form of P2 gas.
Modelling Study of Inclusions Removal by Bubble Flotation in the Tundish
Authors: Ramos‐Banderas A. , Morales R.D. , de J. Barreto J. , Solorio‐Diaz G.
Published: December 2016

Non‐metallic inclusion removal from liquid steel in a tundish is studied using two‐phase flow modelling by Particle Image Velocimetry (PIV) techniques and mathematical simulation. The removal efficiency is studied as a function of Flow Control Devices (FCD) arrangements inside the tundish, gas bubbling and mass flow rate. The mathematical two‐phase model includes an Eulerian‐Eulerian approach for the gas‐liquid system and a Lagrange approach for the solid particles trajectories. The validation of this model was acceptably proved through PIV measurements and colour tracer experiments in a two‐phase water model. The removal efficiency of the tundish in the cases of gas bubbling becomes independent of particle size and FCD arrangements. An increase of mass flow rate decreases the particle mean residence time in the tundish and therefore the removal efficiency. Under the same conditions coupling‐uncoupling phenomena of solid particles from the liquid flow depends strongly on their response time. Where this phenomena occurs, it is determined that the particle response time in the model goes from 10−5 to 10−3 seconds for particle size ranging from 20 to 160 μm, respectively; this transition is dependent on particles size and mass flow rate.
Control of Microstructure during the Eutectoid Transformation in the As‐cast Spheroidal Graphite Cast Iron with »in‐situ« Dilatation Analysis and Quenching Experiments
Authors: Mrvar Primož , Medved Jožef , Križman Alojz
Published: December 2016

Transformation of austenite can proceed into ferrite and graphite (γFe→αFe+ G) and/or in pearlite (γFe→αFe+Fe3C). Investigation of the eutectoid transformation has been undertaken by evaluation of the “in‐situ” dilatation curves in connection with metallographic examinations, DTA and dilatation analyses of the solid state. On a basis of numerous quantitative relations, such as the relation between ferrite and pearlite fractions in as‐cast spheroidal graphite cast iron (SGI), the ratio between ferrite and pearlite in the microstructure is determined in a very short time. Thus the melt composition was corrected using the “in situ” dilatation analyses by addition of Cu and/or Mn or Si respectively. From the kinetics of austenite transformation and temperature dependence of the ferrite or pearlite growth, the following characteristic temperatures of the eutectoid transformation have been established: the ferrite nucleation T0α, the beginning of the ferrite growth Tα, and pearlite growth Tp, respectively. Both temperatures T0α and Tp are determined from the differential inflection point of the dilatometric curves. For mainly ferrite and pearlite SGI, the kinetic curves, which show the fraction of the single microstructure constituents in the microstructure in dependence of the transformation time, are well represented by the physical sigmoidal Boltzmann model. In case of the kinetics temperature dependence, however, pearlite growth does not follow the sigmoidal transformation course, which results from the recalescence of the pearlite reaction. The time of transformation is a more suitable criterion for the description of the transformation.
Reaction between CaO‐SiO2‐Al2O3 Slags and H2 + HCl + H2O Gas Mixtures
Authors: Toyota H. , Hasegawa M. , Oh‐yama S. , Wakimoto K. , Ariyama T. , Asanuma M. , Iwase M.
Published: December 2016

To better understand the thermodynamic behaviour of chlorine in blast furnaces, CaO‐SiO2‐Al2O3 slags were brought into equilibrium with Ar + H2 + HCl + H2O gas mixtures at temperatures between 1673 K and 1798 K. The dissolution of chlorine into molten slags could be well interpreted through a reaction: (1/2) {CaO}slag + (HCl) = {Ca1/2Cl}slag + (1/2) (H2O). Conforming to this formula, a linear relation was observed between log (%CI) and log with an anticipated slope of 1/2.
Hydrogen Potential Sources in Refractory Materials during Steel Casting
Authors: Bragança Saulo Roca , Hohemberger João Marcos , Vicenzi Juliane , Marques Caio Marcelo , Basegio Tânia , Correia Lima Álvaro Niedersberg , Bergmann Carlos Pérez
Published: December 2016

It is well known that the presence of dissolved hydrogen in cast steel can cause defects that appear in hot rolling and forging of steel parts with heavy sections, and also contributes to the formation of internal cracks and blowholes during the solidification of the liquid steel. These problems are especially important in the continuous casting process. So, hydrogen levels must be kept at a minimum in this process. The aim of this work is to investigate possible sources of hydrogen, focusing on the materials that are in contact with the liquid steel during casting. The tundish refractory lining, shrouding tube, tundish covering agents, and casting powders were analysed. The results showed that not only the control of humidity content in those materials is critical, but the phase transformations that the materials suffer during the casting process are important as well.
Strong and Ductile Martensitic Steels for Automotive Applications
Authors: Barani Araz Ardehali , Ponge Dirk , Raabe Dierk
Published: December 2016

The limits of strength and ductility of a medium‐carbon silicon chromium spring steel are investigated for the case of conventional heat treatment including austenitization, quenching and tempering. The effect of phosphorus and austenite deformation prior to quenching was studied by measuring mechanical properties after quenching and tempering and by microstructural investigation. Strong influence of phosphorus on the ductility is observed for the quenched and tempered martensite without prior austenite deformation. The minimum in ductility found after tempering at 350°C is explained by the formation of cementite and grain boundary segregation of phosphorus. Two thermomechanical treatments were tested involving different austenite conditions produced by variation of the deformation temperature. The deformed conditions, recrystallized or work‐hardened, exhibit higher ductility at all tempering temperatures tested. A combined thermomechanical treatment is proposed that provides the highest ductility after tempering at 300°C independent of the phosphorus content. All thermomechanical treatments described in this study refine or eliminate carbide films at prior austenite grain boundaries. It was found possible to increase the tensile strength and the fatigue limit by deformation of austenite prior to quenching while maintaining or increasing the ductility level.
Finite‐Element Implementation of a Self‐consistent Texture Model with a Hardening Law Based on Dislocation Densities
Authors: Walde Tom , Gumbsch Peter , Riedel Hermann
Published: December 2016

A self‐consistent texture model is implemented in the finite‐element code ABAQUS/Explicit®. Hardening of the slip systems is described by evolution laws for dislocation densities, and the Bauschinger effect is included. With these ingredients the cold rolling of an IF‐steel is simulated and the evolution of texture and anisotropy is examined. The use of the dislocation based hardening law is found to have a significant effect on the evolution of the anisotropic yield surface, but only very little influence on the texture.

Furthermore, the hardening model is used to investigate the evolution of dislocation densities in differently oriented grains during plane strain compression. It is found that the dislocation density varies greatly depending on orientation, an observation which can help to explain the orientation dependence of recrystallization.
Material Characterisation for Reliable and Efficient Springback Prediction in Sheet Metal Forming
Authors: Krasovskyy Andriy , Schmitt Winfried , Riedel Hermann
Published: December 2016

In this paper, a novel experimental‐numerical methodology for an accurate prediction of springback after sheet forming is presented. An advanced phenomenological material model is implemented in the FE‐code ABAQUS. It includes the Bauschinger effect, the apparent reduction of the elasticity modulus at load reversal after plastic deformation, the strain rate dependence and the elastic‐plastic anisotropy and its evolution during the forming process. The required material parameters are determined from stress‐strain curves measured in tension‐compression tests. These tests are carried out with a special test rig designed to avoid buckling of the specimens during compression. The benefits of this procedure for springback prediction are demonstrated. Additionally, parameters for the phenomenological models are determined from texture simulations.
Importance of Mineralogical Data for Influencing Properties of Coke: a Reference on Si02 Polymorphs
Authors: Gornostayev Stanislav S. , Kerkkonen Olavi , Härkki Jouko J.
Published: December 2016

SiO2 occurs in coking coals as pure quartz and also in complex aluminosilicates. At coking temperatures, pure SiO2 has several polymorphs (α‐ and β‐quartz and β‐tridymite) and transformations from one to another are accompanied by volume changes in the mineral matter that can lead to the formation of cavities and cracks in a coke matrix. These can weaken the coke physical strength and lead to a higher circulation of gases within the pieces. The grain size of the primary quartz crystals in a coal blend is also important for the estimation of coke strength: the larger the crystals that occur in a coal, the larger the cavities and cracks that will ensue (weaker coke). The occurrence of any given SiO2 polymorph indicates the temperature of its formation and can be used to correlate other changes in coke‐forming compounds with certain temperatures. A high amount of free quartz in a coal blend can be considered a negative factor for coking. For a better understanding of the influence of bulk SiO2 on coke quality, mineralogical (phase) analysis and quartz grain size measurements on coking coals can be helpful. Under the blast furnace conditions, SiO2 polymorphs have no substantial influence on the coke physical strength.
Mass Spectrometric Measurements of the Gas Phase Composition over Mould Powder Samples in Vacuum Conditions at 50‐1550°C
Authors: Shilov Andrei , Holappa Lauri
Published: December 2016

Heating and melting of mould powders in a steel caster may lead to harmful gaseous emissions into the atmosphere. In the present work the volatility of commercial mould powders used in continuous casting processes was studied by the mass spectrometric Knudsen effusion method. Partial pressures of the vapour phase components were measured under vacuum conditions in the temperature range 50‐1550°C at a heating rate of 100°C/hour. In the temperature interval 50‐600°C gas phase is formed by H2O and CO2. At higher temperatures the principle vapour species are Na, NaF, Na2F2, KF, SiF4, SiF2, SiO, CaF2, and CO. Gaseous AIF3, MgF2 and AIOF were identified less reliably. A preliminary decarburised sample exhibited a noticeably different vaporisation pattern. HF was not detected. Under plant conditions SiF4 was pointed out as the most probable air polluting vapour component.
Phase Composition of Oxide Scales during Reheating in Hot Rolling of Low Carbon Steel
Authors: Basabe Vladimir V. , Szpunar Jerzy A.
Published: December 2016

Low carbon steel was oxidized over the temperature range 1000‐1250°C in O2‐CO2‐H2O‐N2, O2‐H2O‐N2, and O2‐CO2‐N2 gas mixtures. Oxidation times were 12‐120 min. and the scales were 50‐2000 μm thick. The variations of these parameters were chosen to elucidate the phase composition of oxide scales under conditions similar to those of reheating furnaces in hot strip mills, using either thin slab casting or conventional casting and rolling technology. Two types of scales have been observed which are influenced by the furnace atmosphere, oxidation time, and temperature. The first type is a crystalline scale with an irregular outer surface, composed mostly of wustite (FeO), and a negligible amount of magnetite (Fe3O4). The second type is the classical three‐layer scale, composed of wustite (FeO), magnetite (Fe3O4), and hematite (Fe2O3). In general, the experiments showed that an increase in oxidation time decreased the percentage of wustite while the percentages of magnetite and hematite increased. A rise in oxygen concentration in the gas mixture increased the percentages of magnetite and hematite, confirming earlier experimental findings. In water vapour‐free atmospheres O2‐CO2‐N2, the oxide scales had a low percentage of wustite, and high percentage of magnetite and hematite. Carbon dioxide showed a small influence at 1100°C, and a negligible one at 1250°C.
Weld Quality Assessment and Actions
Authors: Jonsson Bertil , Samuelsson Jack
Published: December 2016

Since 1989, Nordic industries, organizations and universities have co‐operated in numerous projects related to the design and fabrication of welded structures. In a current ongoing project, QFAB, over 20 participants are working together to improve the design, fabrication and cost effectiveness of complex welded structures.

This paper describes the background to this project and will also discuss the process of quality assessment of welded construction machinery. The main part of the supporting framework on vehicles consists of welded steel structures. These welds contain defects and imperfections from the weld process itself and when severe load conditions are present, a finite life is at hand. The competition among manufacturers towards higher productivity and lower fuel consumption drives the engineers to design lighter structures preferably in high strength material. Such a design requires a higher weld quality and calls special attention to design and manufacturing of welds. A major issue is thus to form a scientific and consistent base which can be used when analysis and design is integrated with production and quality inspection of components. The goal is to build world class vehicles for operation without failures in service during the economic life.
LEFM Analysis and Service Simulation Testing of a Welded Frame Structure
Authors: Byggnevi Magnus
Published: December 2016

In this paper the results from fatigue analysis and testing of a welded frame are discussed. The structure contains some typical welds, which can be found on a frame to a wheel loader. The test was carried out with a service load spectrum with an overall stress ratio, R, of about ‐1. The fatigue cracks started from the root side of the welds in all cases. The test results were correlated with linear elastic fracture mechanics (LEFM) including different assumptions of residual stress distributions.
A Study of Thickness Effect on Fatigue in Thin Welded High Strength Steel Joints
Authors: Gustafsson Mats
Published: December 2016

It is well known that the fatigue strength of welded joints decreases when plate thickness increases. This decrease in fatigue strength is known as the thickness effect. In many standards for fatigue design the thickness effect is taken into account for joints with plate thickness typically greater than 25 mm. Previous work has mainly been focused on joints with plate thickness between 12‐200 mm. Less attention has been paid to thinner joints. Published investigations on joints with sheet thickness 2‐12 mm show an increase of fatigue strength with decreasing sheet thickness. In the present study results from constant amplitude fatigue testing of non‐load carrying welded joints in high strength steel of thickness 3‐12 mm are presented. The results show an increase in fatigue strength with decreasing sheet thickness down to 3 mm. Fracture mechanics calculations confirm the test results.
Fatigue Assessment of Cruciform Joints Welded with Different Methods
Authors: Barsoum Zuheir , Samuelsson Jack
Published: December 2016

The advantages of the relatively new laser welding method are low welding distortions and high productivity, and it opens new opportunities for welding of steel structures in the automotive and heavy machinery industries. There is a need for understanding the fatigue strength and to develop fatigue design curves for laser welded joints. In this paper fatigue testing and weld quality of Hybrid Nd: YAG laser/MAG and MAG welded non‐load carrying cruciform joints is examined. Four batches were produced, tested and the results were compared. The local weld geometry of the cruciform welded joints was measured and analysed. The measured parameters were used to calculate the stress concentration factors by implementing FE‐models, in order to anticipate the influence of size of weld geometrical parameters on the stress concentrations. Residual stress measurement was carried out close to the toe region using the X‐ray diffraction method and weld defects (cold laps) in the cracked specimens was measured.
Deformation Characteristics of Steel Billets with Liquid Core
Authors: Wang Wenjun , Bülte Raimund , Bleck Wolfgang
Published: December 2016

To investigate the deformation characteristics of billets with liquid core during soft reduction and to clarify the correlation between internal cracks and deformation of the billet in the mushy zone, a fully coupled thermo‐mechanical Finite Element Model was developed in ABAQUS, furthermore, casting and soft reduction tests were carried out in a laboratory strand casting machine. During soft reduction the temperature distribution, the stress and strain states in the billet were calculated, the deformation characteristics of the billet during soft reduction were determined and the relation between internal cracks and equivalent plastic strain as well as maximal principal stress was analysed. The results show that tensile stresses can develop in the mushy zone during soft reduction and the equivalent strain nearby the Zero Ductility Temperature (ZDT) increases with a decreasing solid fraction. Internal cracks can be initiated when the accumulated strain exceeds the critical strain and /or the applied tensile stress exceeds the critical fracture stress during solidification. In addition, the factors (reduction efficiency and internal cracks) that should be considered to determine the optimal parameter for the soft reduction were established.
Thermodynamics of Aluminium in Molten Zinc with the use of Electrochemical Sensors
Authors: Pouri Masoumeh Hossein , Soltanieh Mansour
Published: December 2016

In the present study the thermodynamics of aluminium in molten Zn‐Al was determined at the temperatures 470, 490 and 520°C with the use of electrochemical sensors. Cell and sensor techniques were used. The following concentration cell was used: Al (pure reference) |Al3+ (in fused salt) | [Al]in zinc. It was found that the activity of aluminium shows positive deviation from Raoult's law. The partial heat of solution of aluminium at temperatures between 470 and 520°C for XAl = 0.004 was determined as = 21882 J. The dilute solution of aluminium in zinc in the range of 0≤XAl≤0.044 obeys Henry's law. The Wagner's first order interaction coefficient eAlAl was determined.
Adhesive Behaviour of BOF Slag to BOF Lining Refractory in Slag Splashing Process
Authors: Zhong Liangcai , Zhu Yingxiong
Published: December 2016

A slag layer is formed when slag is splashed onto refractory lining in BOF slag splashing process. The melting temperature of the slag layer and the adhesion of the slag layer to the lining refractory have an important effect on slag splashing and BOF lining life. This study investigates the adhesive behaviour of slag with different composition to lining refractories. It is shown that the slag can adhere to MgO particles in MgO‐C bricks well and no reaction is found between the MgO particles and the slag layer, but a gas gap exists at the interface between the slag layer and the MgO‐C matrix and there are iron granules within the slag layer, when the FeO content in the slag is high. The adhesion of the slag layer to the lining refractory can be improved with decreasing FeO content in the slag and lower carbon content in the MgO‐C bricks. BOF refractory lining life can be greatly increased due to better adhesion, high melting temperature, and stronger wear‐resistance of the slag layer.
Service Reliability Assessment of Weld Repaired CrMoV Steel Rotors
Authors: Wang Guodun , Indacochea J. Ernesto , Oh Youngkun
Published: December 2016

This research deals with the service evaluation of a retired CrMoV steel rotor that has been repaired using deep groove multi‐pass submerged arc welding (SAW) and gas tungsten arc welding (GTAW). Accelerated creep tests were conducted at several elevated temperatures and extrapolated to the service temperatures. The coalescence of carbides and cavity growth during creep were evaluated. For the CrMoV‐GTAW samples, it was found that the creep life depended on the location of the crossweld in the welded specimen. The service lives of the weldments were extrapolated.
Corrosion Resistance of Reactive Element Aluminide Diffusion Coatings on a Nickel‐based Superalloy and an Austenitic Stainless Steel
Authors: Raouf Elsawy Abdel , Soda Hiroshi , McLean Alexander
Published: December 2016

Continuously cast aluminium alloy wires containing active elements such as yttrium, cerium, lanthanum or silicon were used as evaporation sources for ion vapour deposition on nickel‐based Inconel IN738 and stainless steel 310S substrate materials. The samples were subsequently diffusion heat‐treated to form protective corrosion resistant nickel aluminide and iron aluminide coatings. The coated alloy materials were exposed for prolonged periods to high temperature cyclic oxidation, molten sulphate, and molten carbonate environments to evaluate their resistance to hot oxidation. For IN738, the lanthanum‐modified aluminide coating provided good thermal cyclic oxidation performance while the cerium‐modified coating exhibited effective hot corrosion resistance in a molten sulphate environment. For 310S stainless steel, all of the modified aluminide coatings provided equally good corrosion protection when exposed to molten carbonate attack under an oxidizing atmosphere.
Plasma Reduction of Iron Oxide by Methane Gas and its Process Up‐scaling
Authors: Badr Karim , Bäck Eduard , Krieger Wilfried
Published: December 2016

This paper investigates the characteristics of the methane plasma reduction of iron ore in comparison to that of the hydrogen plasma reduction process. Although hydrogen plasma smelting reduction (HPSR) has potential advantages as a steelmaking alternative in terms of simplicity (less operation units) and less harmful detrimental environmental implications, its high cost has a negative influence on its usage. In this regard, natural gas (> 96 % methane) could be adopted in the field of plasma smelting reduction. A brief comparison between hydrogen and methane options has been carried out experimentally. Heat and mass balance models were conducted to explore the features of up‐scaled processes with respect to consumption figures and CO2 emissions. It was found that the methane plasma is a good alternative iron oxide smelting process.