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Frontmatter

Casting and Solidification Processes

Frontmatter

Influence of Scale Formation on Copper Enrichment Behaviour in Continuously Cast Slab

Abstract
Copper enrichment behavior in continuously cast slab induced by scale formation after continuous cooling in H2O vapor atmosphere and consecutively in air has been experimentally investigated by combining with SEM-EDS analysis, for the purpose to examine the effects of initial slab surface temperature and contents of copper and nickel. For Slab 1 with copper content of 0.1 percent, no visible copper enrichment is found at scale-substrate interface irrespective of the various scale microstructures formed at different initial slab surface temperatures. For Slab 2 with higher contents of copper and nickel, copper-rich phase accumulates and stays at scale-substrate interface under the condition of lower initial slab surface temperature; while Cu-rich phase in the porous scale formed at higher initial slab surface temperature is noted with simultaneous Ni-emichment appearing in front of the steel-scale interface. Both a porous scale and high nickel content work together to provide pores for copper-rich phase migration away from interface and occlude within the scale layer.
Nan Wang, Shan Yu, Xiaoao Li, Jianhua Xin, Guanghao Chen, Min Chen, Cuihuan Huang

Physical Simulation of Critical Blowing Rate of Slag Entrapment of 80 Tons Ladle

Abstract
The slag entrapment under different conditions of 80t blowing argon ladle furnace was investigated by physical simulation. The water was used to simulate liquid steel and liquid paraffin was for slag. The processing of slag entrapment under different blowing structures was analyzed and the critical velocity and critical droplets diameter of describing it was obtained. Based on the experiments, the relationship between the interface flow velocity and the critical blowing rate (CBR) was deduced. In the real process, it is suggested that the bottom blowing rate is from 40 L/min to 180L/min when the interface tension is 0.12~1.2 N/m during the soft argon blowing.
Rui Wang, Yanping Bao, Yihong Li, Aichun Zhao, Yafeng Ji, Xiao Hu, Qingxue Huang, Jiansheng Liu

Liquid Metal Modelling of Flow Phenomena in the Continuous Casting Process of Steel

Abstract
The quality of the produced steel in the continuous casting process is significantly governed by the melt flow in the mold. However, direct flow measurements in liquid metals are still rather scarce. In order to investigate these flow phenomena, three experimental facilities operating with low melting liquid metals were installed at Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The melt flow in the models is measured by the Ultrasonic Doppler Velocimetry (UDV) or the Contactless Inductive How Tomography (CIFT), multi-phase flows can be visualized by X-ray imaging. The obtained measurement results are primarily used for validation of numerical models.
In this paper we will investigate the fluid flow in the mold and the behavior of the surface of the liquid metal using flow measurements by UDV and surface profile measurement by a laser scanner, respectively. Strong fluctuations and deviations of the free surface were observed in case of a static magnetic field.
K. Timmel, B. Willers, T. Wondrak, M. Röder, N. Shevchenko, G. Gerbeth, S. Eckert

Non-Ferrous Extractive Metallurgy

Frontmatter

The Cu-Ni-S System and Its Significance in Metallurgical Processes

Abstract
Due to increasing complexities of raw materials for base metals production the conventional pyrometallurgical processes are challenged. To make the appropriate modifications, thorough evaluations of the thermal stabilities of phases and phase assemblages which are commonly encountered in these processes are essential. In this work, phase relations and thermal stabilities of equilibrium phases in the Cu-Ni-S system have been reviewed. The calculated phase diagram of Cu-N system has been validated. At T > 630 K, in the N-rich corner, large scatter in data has been observed and discussed in detail. The other binary systems, Cu-S and Ni-S, have been also critically reviewed together with the ternary Cu-N-S system. The reviews were focused on compiling and discussing phase relations and thermal stabilities of the selected systems in the pyrometallurgical processes of Cu and N productions.
Fiseha Tesfaye, Daniel Lindberg, Pekka Taskinen

Iron and Steelmaking — Thermodynamic, Reduction and Physical Metallurgy

Frontmatter

Reduction Kinetics of Magnetite Concentrate Particles with Hydrogen at 1150–1600 °C Relevant to a Novel Flash Ironmaking Process

Abstract
A novel ironmaking process is under development at the University of Utah aimed at producing iron directly from iron oxide concentrate in a flash reactor. This process will reduce hazardous emissions and save energy. The kinetics of magnetite reduction with hydrogen was previously investigated in our laboratory in the temperature range 1150 to 1400 °C at large temperature increments (~100 °C increments). Due to the significant melting that occurs above 1350 °C, the reduction kinetics was measured and analyzed in two distinct temperature ranges of 1150 to 1350 °C and 1350 to 1600 °C (~50 °C increments). Experiments were performed using magnetite concentrate particles of different sizes under various hydrogen partial pressures and residence times. Reduction degrees of more than 90 % were achieved in a few seconds at temperatures as low as 1250 °G Different rate expressions were needed to obtain reliable agreement with experimental data.
Mohamed Elzohiery, Yousef Mohassab, Amr Abdelghany, Shengqin Zhang, Feng Chen, Hong Yong Sohn

Hydrogen Reduction Kinetics of Mechanically Activated Magnetite Concentrate

Abstract
The effect of mechanical activation on the reduction kinetics of magnetite concentrate by hydrogen was studied. The magnetite concentrate was milled for 8 h using a planetary mill. After the milling process, the average particle size was reduced from 14 to 4.4 µrn resulting in a lattice microstrain of 0.30. Thermogravimetric experiments were conducted to focus on the chemical reaction as the rate controlling factor by eliminating external mass transfer effects and using a thin layer of particles to remove interstitial diffusion resistance. The onset temperature of reduction was decreased due to the mechanical activation, and the degree of conversion was decreased by sintering of particles which was confirmed by SEM analyses. In view of the results, a reaction rate expression is discussed from which the activation energy is calculated.
Ricardo Morales-Estrella, Juan Ruiz-Ornelas, Yousef Mohassab, Noemi Ortiz-Lara, Hong Yong Sohn

Influences of Thermomechanical Processing on the Microstructure and Mechanical Properties of a HSLA Steel

Abstract
High strength low alloy (HSLA) steels with high strength, high toughness, good corrosion resistance and weldability, can be widely used in shipbuilding, automobile, construction, bridging industry, etc. The microstructure evolution and mechanical properties can be influenced by thermomechanical processing. In this study, themomechanical processing is optimized to control the matrix microstructure and nano-scale precipitates in the matrix simultaneously. It is found that the low-temperature toughness and ductility of the steels are significantly the matrix microstructure during enhancing the strength by introducing the nano-scale precipitates. The effects of alloying elements on the microstructure evolution and nano-scale precipitation are also discussed.
Yu Zhao, Songsong Xu, Yun Zou, Jinhui Li, Z. W. Zhang

Behaviors and Evolutions of MgO·Al2O 3 in Non-Oriented Silicon Steel During Calcium Treatment

Abstract
Behaviors and evolutions of MgO·Al2Q3 in non-oriented silicon steel during calcium treatment were investigated by thermodynamic calculations and high-temperature experiments. MgO·Al2O3 inclusions were the main type of inclusions before calcium treatment, which is also confirmed by the stability diagram of MgO/MgO Al2O3/Al2Q3 from thermodynamic calculations. After calcium treatment, the majority of original MgO·Al2Q3 inclusions were mainly modified to CaO-MgO-Al2Q3 system inclusions, this would be beneficial to improve castability and product quality of silicon steel. But there was no modification happening to some MgO·Al2Q3 spinels which were directly surrounded by CaS inclusions. The content of Al2O3 occasionally existed a sudden increase besides a common decrease in the product layer of CaO·MgO Al2O3. Then the evolution mechanisms of MgO·Al2O3 inclusions were proposed in present work. Thus, Al/Mg atom ratio had a significant influence on the modification of MgO·Al2O3 spinel.
Yong Zhao, Yan-hui Sun

Forming, Joining, Sensing: Devices and Applications

Frontmatter

Evaluation of Joint Performance on High Nitrogen Stainless Steel Which is Expected to Have Higher Allergy Resistance

Abstract
Austenitic stainless steel, which includes nickel for stabilizing austenitic structure, is used for various purposes, for example, for structural material, corrosion-resistant material, biomaterial etc. Nickel is set as one of the rare metals and economizing on nickel as the natural resources is required. On the other hand, nickel is one of the metals that cause metallic allergy frequently. Therefore, high nitrogen stainless steel, where nitrogen stabilizes austenitic structure instead of nickel, has been developed in Japan and some of the foreign countries for the above reason. When high nitrogen stainless steel is fused and bonded, dissolved nitrogen is released to the atmospheric area, and some of the material properties will change. In this study, we bonded high nitrogen stainless steel by stud welding process, which is able to bond at short time, and we evaluate joint performance. We have got some interesting results from the other tests and examinations.
Kouichi Nakano

Poster Session

Frontmatter

Obtaining Multiple Metals Through Electron Beam Melting of Refractory Metal Wastes

Abstract
Investigations and results on the refining of tungsten scrap applying electron beam melting (EBM) in vacuum are presented and discussed. In this work EB melting experiments were performed in single or double-melt operations with different power inputs and refining times for tungsten purification and recovery of multiple metals (including refractory and other metals such as Mo, Nb, Cu, Zn, etc.), which are alloyed elements or impurities with high concentrations in the initial materials. Evaluations for extraction of some valuable metals, generated in the condensate at their removal from the liquid metal during the refining process are provided. Efficient technological regimes for e-beam melting and refining that enable the simultaneous production of pure metal ingots and condensates that can be used directly or can be used for subsequent extraction of expensive and valuable metals are presented.
Katia Vutova, Vania Vassileva

Solidification and Evaluation of Thermal Parameters of Sn-Zn Eutectic Alloys Horizontally Solidified

Abstract
In the present research the horizontal solidification of Sn-Zn eutectic alloys (Sn-8.9wt.%Zn) is performed, with two opposite senses of heat extraction. From the process of solidification, the thermal parameters (local solidification time, cooling rates and interphases velocities) and grain sizes from macrostructures obtained were determined. The presence of defects in the solidified samples was analyzed, observing that they occur largely in the collision zones of solidification fronts advancing in opposite directions in the samples.
Alex Iván Kociubczyk, Roberto Rozicki, Verónica Liliana Scheiber, Alicia Esther Ares

Laser Ablation of Aluminum and Titanium Alloys Under Glass Confinement

Abstract
Single-pulse laser ablation of aluminum and titanium alloys under glass confinement is investigated. Processing parameters such as laser intensity and gap width between targets and glass are varied. Surface morphologies and crater profiles of the alloys after laser ablation are studied by SEM and white-light interferometric microscope, respectively. The effects of gap width and laser intensity on surface morphologies and crater profiles of targets are systematically analyzed. In addition, the generation of porous surface structures in Ti target is regarded as the result of phase explosion in the molten surface layer of targets and the thermodynamic condition in our experiment for phase explosion is evaluated.
Peixuan Ouyang, Liangju He, Peijie Li

The Cooling Ability Study on CO2 and O2 Mixed Injection in Vanadium Extraction Process

Abstract
Carbon dioxide could be utilized as a weak oxidant and a kind of coolant to oxidize elements, meanwhile, helping control the temperature during the converter vanadium extraction process. However, the optimum content of CO2 and the cooling effect of CO2 at low content have not been reported. In this study, experimental research based on the influence of different CO2 contents from 0% to 25% injected to the vanadium-containing hot metal was carried out, as well as contrast experiments of O2-N2 mixed blowing. The results indicated that the optimum content of CO2 was 15%. Under the optimum condition, the oxidation of [C] was the lowest and the oxidation rate of [V] was 96.9%, while the temperature was also lower than the O2-N2 mixed blowing. This paper provide a potential property for utilizing CO2 during the converter vanadium extraction process.
Pengcheng Li, Yu Wang, Wei-Tong Du, Gang Wen

Effect of MnO on Sintering and Microstructure of Al2O3-MgO-CaO Refractories

Abstract
In the current study, Al2O3-MgO-CaO refractories were prepared at 1400–1600°Cby the addition of MnO micro-powders, and the effect of MnO addition on densification behavior of the refractory was discussed. The results showed that the doped MnO dissolved to MgAl2O4 phase, and promoted the growth of MgAl2O4 grains by the formation of MgAl2O4 solid solution. As a result, the dense microstructure was obtained, with the apparent porosity decreased from 19.2% to 5.4% and the bulk density increased from 2.78g/cm3 to 3.15g/cm3 after firing at 1600°C for 2h by the addition of 4% MnO. In addition, a texture microstructure was observed, which is considered to be favorable to improve mechanical properties and the service life of Al2O3-MgO-CaO system refractories.
Xue-liang Yin, Lei Liu, Xiang Shen, Mei-le He, Lei Xu, Nan Wang, Min Chen

Determination of Total Iron Content in Iron Ore and DRI: Titrimetric Method Versus ICP-OES Analysis

Abstract
The determination of reduction degree in a DR process is sensitive to the total iron in the ore and DRI. An accurate and high throughput analysis method for total iron has been developed. Titration of the solution after tin(II) chloride reduction of ferric ion is a widely used method foriron analysis. However, it is a multistep method that requires many chemical reagents and much time. In this work, an ICP-OES analysis method with higher or equivalent accuracy compared with the titrimetric method was developed. This method has much higher throughput and demands fewer chemical reagents compared with the titrimetric method. In this paper, a comparison of the two methods is presented.
Yousef Mohassab, Mohamed Elzohiery, Feng Chen, Hong Yong Sohn

Effective Inoculation of Grey Cast Iron

Abstract
The study proves that by introducing the iron powder and disintegrated steel scrap to low-sulphur cast iron still before the inoculation carried out with a conventional graphitising inoculant, the mechanical properties similar to those obtained during the inoculation treatment carried out on cast iron with the recommended high sulphur content are achieved. The said operation increases the number of crystallisation nuclei for dendrites of the primary austenite. In this case, the iron particles act as substrates for the nucleation of primary austenite, due to a similar crystallographic behaviour of the regular face centred cubic lattice The more numerous are the dendrites of primary austenite, the less free space is available in the interdendritic spaces for the formation of graphite eutectic grains, which makes the structure more refined (more eutectic grains) and the mechanical properties higher.
Dariusz Kopyciński, Józef Dorula

Study on the Infrared Spectral Range for Radiation Temperature Measurement of Continuous Casting Slab

Abstract
The surface temperature of continuous casting slab in the secondary cooling zone is a key parameter of production control. However, the accuracy of radiation temperature measurement of high temperature casting slab is greatly affected by the environmental factors, such as water vapor, spray, water film and other participational medias during continuous casting process. In this paper, the radiation characteristics of water vapor and its influences to radiation temperature measurement of continuous casting slab were investigated. Based on the database HITRAN 2004 and the measuring principle of monochrome thermometer & colorimetric thermometer, the measuring errors under different operating infrared spectral wavelength were compared. Results showed that spectral region with wavelength nearby 1.0 m or 1.6 m would be the optimum for high temperature infrared thermometer used under the conditions with moist steam, water spray and water film at the secondary cooling zone in steel continuous casting.
Yunwei Huang, Dengfu Chen, Lin Bai, Mujun Long, Kui Lv, Pei Xu

Behavior of Quartz and Carbon Black Pellets at Elevated Temperatures

Abstract
This paper studies the quartz and carbon black pellets at elevated temperature with varying temperature and gas atmosphere. High-purity quartz and commercial ultra-pure carbon black was mixed (carbon content vet. 15%), and then pelletized into particles of l-3mm in diameter. The stoichiometric analysis of the pellet during heating is studied in thermogravimetric analysis (TGA) furnace at different temperature in CO and Ar atmosphere. The microstructure, phase changes and element content of sample before/after heating is characterized by X-ray diffraction, scanning electron microscope, X-ray fluorescence and LECO analyzer. The reaction process can be divided into two stages. Higher temperature and argon atmosphere are the positive parameters for SiC formation.
Fei Li, Merete Tangstad

Advanced Characterization Techniques for Quantifying and Modeling Deformation

Frontmatter

Interrupted Quasi-static and Dynamic Tensile Experiments of Fully Annealed 301 Stainless Steel

Abstract
This research examined the evolving microstructure of quasi-static and dynamically loaded fully annealed metastable 301 austenitic stainless steel (SS). Experiments were performed to an interrupted strain value of 20% and to failure using a tension Kolsky bar (1000/s) and an electromechanical load frame (0.001/s). Electron Backscatter Diffraction (EBSD) identified the microstructural evolution from the as-received condition to the 20% strain level for the high and low rate interrupted samples. This material achieved over 60% elongation to failure with increasing strength as strain rate increased, as expected. Fractography analysis using SEM showed particles in the microstructure and a ductile failure mode. The 301 SS exhibited a greater amount of phase transformation from parent austenite to α’-martensite at the dynamic strain rate when compared to the quasi-static strain rate during the interrupted experiments. This result is indicative of the increased propensity for austenite to α’-martensite phase transformations at the high strain rate.
O. G. Rivera, Z. McClelland, P. Rivera-Soto, W. R. Whittington, D. Francis, R. D. Moser, P. G. Allison

Evolution of Void Shape Anisotropy in Deformed BCC Steels

Abstract
Microstructural analysis to support the development of material models provides valuable information to design complex forming operations. Damage models such as e.g. by Gurson consider spherical voids only. However, investigations of bee steels by scanning electron microscopy reveal that voids exhibit an ellipsoidal shape with progressing deformation. The material’s weakening in the Gurson model is taken into account by the void volume fraction. Therefore, a three-dimensional characterization of the void shape offers important data for modelling. Thus, information on the anisotropy of the process of void evolution and accordingly, about the anisotropy of the deformation process is provided. Application of the information regarding the void shape anisotropy within the Gurson model is discussed.
Gregory Gerstein, Florian Nürnberger, Hans Jürgen Maier

Backmatter

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