Practice Of Metallurgy Research Articles

The Study of The Level of Environmental Consciousness and the Efficiency of Environmental Education Students

The Study of The Level of Environmental Consciousness and the Efficiency of Environmental Education Students

Review, Analysis, and Modeling of Continuous Casting Tundish Systems

Computational studies of steelmaking tundish systems date back to early eighties. Two independent overviews, published, respectively, in 1999 and 2010, summarize a large number of research work reported by various groups of investigators. These indicate that modeling of tundish metallurgy is primarily restricted to the steady operating period, and phenomena such as, fluid flow, turbulence, thermal and material mixing, inclusion floatation, and removal etc. are given wide attention. Toward this, homogeneous, turbulent flow modeling is relatively more frequent. Since 2008 or so, transient and multi‐phase modeling of tundish metallurgy are popular and reported by some groups of investigators. This paper presents a brief summary and a critical assessment of such efforts vis a vis industrial tundish metallurgy practices. Despite advancements in theory and powerful computational procedures, it is brought out that progress in mathematical modeling of tundish metallurgy, particularly during the last decade, is somewhat sluggish. In the final section of the manuscript, an account of continuing efforts of the author and his associates are presented, wherein, modeling of two phase flows in ladle shroud and latter's attendant influences on the metallurgical performance of steelmaking tundish is discussed.

Using X-Ray Fluorescence to Examine Ancient Extractive Metallurgy Practices: A Case Study from Iron Age Khirbat al-Jariya, Jordan

The first industrial revolution to appear in the southern Levant (Israel, Jordan, Palestine, Lebanon, southern Syria and the Sinai Peninsula) occurred during Iron Age (ca. 1200-500 BCE) when large scale copper smelting occurred. The hub of this technological development occurred in the Faynan region of Southern Jordan, which is home to the largest copper ore deposits in the southern Levant. Throughout history, these abundant ores were exploited by local populations with copper production reaching an industrial scale in the 10th and 9th centuries BCE. The evidence for this massive production remains visible on the surface throughout Faynan at ancient smelting sites populated with large heaps of industrial copper slag. Khirbat al-Jariya (KAJ), one such copper smelting center, was the focus of renewed excavations by the Edom Lowlands Regional Archaeology Project in the summer of 2014. In order to investigate the history of metal production at KAJ, a test probe was excavated into one of the site’s slag mounds. The 1×1 meter sounding was excavated to bedrock to provide a complete representation of copper smelting activities during the site’s history. To supplement excavations, our team collected geo-referenced slag samples from stratigraphically controlled contexts within the probe and from several other slag mounds around the site at KAJ. These samples were subsequently the focus of post-season X-Ray Fluorescence (XRF) analysis to provide insight beyond the visible record. By combining the XRF results with the chronological framework provided by archaeological excavation, it is possible to examine diachronic changes in the elemental compositions of the slag samples. In turn, the elemental contents of the slag can be used as a proxy for evaluating the extractive metallurgy practices of the ancient metalworkers. Thus, this paper presents the results of the XRF analyses and the possible conclusions to be drawn concerning ancient copper smelting at Khirbat al-Jariya.

Preface to the Special Topic on AdMet 2015

The International Conference on Advances in Metallurgical Processes and Materials (AdMet 2015) was held in Kyiv, Ukraine, on June 3–5, 2015, and researchers and engineers from 12 countries attended the event. The first AdMet conference was held on 2007 in Dnipropetrovsk, Ukraine, and the second conference was initially planned for 2014. However, because of the political situation in Ukraine, it was rescheduled for 2015. Despite the intentions expressed by the organizers to relocate the conference to another country, they decided to keep it in Ukraine to reflect the substantial contributions made by Ukraine to the theory and practice of metallurgy. The local organization of AdMet 2015 was supported by the Paton Electric Welding Institute, National Metallurgical Academy of Ukraine, and Elmet-Roll Company. Multidisciplinary cross-country collaboration is becoming increasingly important with respect to sustainable development targets. Therefore, the purpose of AdMet 2015 was to bring together researchers from the domains of process metallurgy and materials science in order to share the latest advances in research and development, assist international collaborations for solving current and future societal and technological challenges, and promote the transfer of innovative technologies and materials. The conference topics covered thermodynamics, innovative metallurgical processes, advances in ironand steel-making technologies, process control, automation, online analysis, the design and properties of materials, modeling and simulation processes and materials, special melting, and environmental issues in metallurgy. From the proceedings of AdMet 2015, we have chosen several articles that discuss the environmental issues in metallurgy, especially the recycling, recovery, and reuse of by-products and waste, to meet the scope of the Journal of Sustainable Metallurgy. In addition, one review paper discussing the present situation of the steel industry in Ukraine is included. We hope this special topic is useful to many researchers by providing updates on the recent advances in this field. The third AdMet will be held in Lviv, Ukraine, in 2018, and it is our pleasure to invite the readers of the Journal of Sustainable Metallurgy to this conference.

Influence of residual porosity on the dry and lubricated sliding wear of a powder metallurgy austenitic stainless steel

Powder metallurgy practices offer the opportunity to control the porosity of steels for tribology applications. The material of interest was an austenitic powder metallurgy stainless steel sintered in a nitrogen atmosphere. Four disc samples with increasing porosity (from 8% to 29%) were subjected to dry and lubricated sliding against an alumina pin using a rotary pin-on-disc tribometer. An estimation based on Hertzian contact analysis has been introduced to define the size of large pores. A normalized scar depth has been defined. The influence of pores on Archard׳s wear law has been analysed. Dry sliding, liquid lubrication, and self-lubrication (filled pores) were all evaluated. During the first few metres of dry sliding, the pores are closed by plastic deformation. After that, the wear rate can be considered the same. In lubricated conditions, pores are not closed and the higher the porosity, the lower the wear rate. In filled-pore, self-lubricated conditions, the sample with the highest porosity showed the lowest wear rate. Reasons for this behaviour are discussed.

Optimisation of stainless steel cold spray coatings using mixed particle size distributions

Porosity in type 316 L stainless steel cold spray coatings is studied from two different aspects. The first is to examine, for a given level of porosity, the effect of coating thickness on corrosion behaviour. Beyond a critical coating thickness the substrate is no longer attacked in polarisation tests, which has implications for coatings that contain some porosity (including some thermal spray coatings). The second aspect examined is to approximate the stainless steel particles as non-deforming, and apply the powder metallurgy practice of mixing particle size distributions to improve coating density. The results show that coatings sprayed using mixed particle size distributions can have similar properties to those sprayed using fine particles alone, but without the processing difficulties of fine particles such as inconsistent powder feeding or nozzle fouling.

A Unified Approach to the Fluid Dynamics of Gas–Liquid Plumes in Ladle Metallurgy

The paper focuses on the fundamental aspects of the fluid mechanics of unconstrained gas–liquid plumes relevant to Ladle Metallurgy Practice. A mathematical model previously proposed by the authors is justified by comparison with Eulerian–Lagrangian models. Further, a unified analytical framework is proposed to describe the fluid dynamic and similarity characteristics of two-phase plumes. Despite the apparent complexity of the system, the analysis demonstrates that the plume cross-sectional area, void fraction and gas and liquid velocities can be quantified in terms of two parameters: a dimensionless gas flow rate and the normalized axial height. The analysis clarifies the proper form of the Froude number similarity which is important for process design and scale-up.

Traditional Metallurgy, Nanotechnologies, and Structural Materials: A Sorby Award Lecture

Traditional metallurgical processes are among the many “old fashion” practices that use nanoparticles to control the behavior of materials. Many of these practices were developed long before microscopy could resolve nanoscale features, yet the practitioners learned to manipulate and control microstructural elements that they could neither see nor identify. Furthermore, these early practitioners used that control to modify microstructures and develop desired material properties. Centuries old colored glass, ancient high-strength steels and medieval organ pipes derived many of their desirable features through control of nanoparticles in their microstructures. Henry Sorby was among the first to recognize that the properties of rocks, minerals, metals, and organic materials were controlled by microstructure. However, Mr. Sorby was accused of the folly of trying to study mountains with a fsmicroscope. Although he could not resolve nanoscale microstructural features, Mr. Sorby’s observations revolutionized the study of materials. The importance of nanoscale microstructural elements should be emphasized, however, because the present foundation for structural materials was built by manipulating those features. That foundation currently supports several multibillion dollar industries but is not generally considered when the nanomaterials revolution is discussed. This lecture demonstrates that using nanotechnologies to control the behavior of metallic materials is almost as old as the practice of metallurgy and that many of the emergent nanomaterials technologists are walking along pathways previously paved by traditional metallurgists.

Rapid solidification of copper alloys with high strength and high conductivity

Rapid solidification has been employed to develop high-strength/high-conductivity copper alloys, because it offers advantages not achievable by conventional ingot metallurgy practice. The effect of rapid solidification on mechanical properties and electrical conductivity on copper alloys (with and without heat treatment) has been studied. Results indicated that alloys of the Cu-Cr-Zr type, rapidly solidified and aged, show a good combination of electrical conductivity [45.82 × 106(l/Ω · m)] and microhardness Vickers (24.46 × 106 Pa) values. These values are superior to those of optimally aged conventional copper alloys for resistance welding electrode applications.

Technological principles behind making the heating of steelmaking baths more efficient and reducing pollution

Improving the efficiency of the heating of the steelmaking bath through the use of oxygen while reducing pollution remains one of the most difficult but important problems in the science and practice of metallurgy. Of the different high-productivity steelmaking methods now used, the oxygen-converter method is the leading technology: the unit consumption of oxygen averages 65 m3/ton in oxygen-converter steelmaking, 30 m3/ton in electric steelmaking, 60 m3/ton in open-hearth practice, and 70 m3/ton in two-bath furnace steelmaking. Most of the oxygen is consumed in refining processes.

Effective moduli of high volume fraction particulate composites

Predictions using current micromechanics theories for the effective moduli of particulate-reinforced composites tend to break down at high volume fractions of the reinforcing phase. The predictions are usually well below experimentally measured values of the Young's modulus for volume fractions exceeding about 0.6. In this paper, the concept of contiguity, which is a measure of phase continuity, is applied to Mori—Tanaka micromechanics theory. It is shown that contiguity of the second phase increases with volume fraction, leading eventually to a reversal in the roles of the inclusion and matrix. In powder metallurgy practice, it is well known that at high volume fractions, sintering and consolidation of the reinforcement make it increasingly continuous and more like the matrix phase, while the former matrix tends to become more like the inclusion phase. The concept of contiguity applied to micromechanics theory results in very good agreement between the predicted Young's modulus and experimental data on tungsten carbide particulate-reinforced cobalt.

Measurements, models, and mathematics of alloy systems

The classical phase studies of Hume-Rothery and co-workers extended the work of Dolezalek and Hildebrand. The demonstration of the importance of the electron concentration in addition to the atomic concentrations gave rise to such developments as Miedema's treatment of intermetallic compounds and the Brewer-Engel theory. The experimental techniques, to which Dr. Kleppa has made distinguished contributions, have provided partial thermodynamic data for many binary systems but complete descriptions are usually absent because of the shortcomings of available techniques. Applications of newer methods for structural analysis have not yielded substantial guidance to the practical metallurgist. The most successful predictions have been based on simple approximations to the Gibbs- Duhem equation with experimental data for binary systems. More “physically correct” analyses through ab initio calculations seem a long way from the practice of metallurgy.

Physicochemical considerations in powder metallurgy

Powder metallurgy (P/M) is now recognized as a viable net-or near-net-shape manufacturing technology. Innovative methods of powder production and consolidation, currently under development, are expected to further enhance P/M processing technology compared to ingot metallurgy practice. Optimization of these particulate processing technologies mandates a basic knowledge of the physicochemical behavior of the powder during production and on subsequent processing into final part form. Consideration of the relationship between P/M and physical chemistry illustrates the benefits derived from controlled chemical reactions, as utilized in several commercial and near-commercial powder processing technologies.

Charles S. Barrett: X-Ray Metallurgist — An Informal Portrait

Charles Barrett's work in phase transformation at the atomic level helped redefine the underpinnings of the science and practice of metallurgy. His work in low temperature physical chemistry has extended its range. And, perhaps more than anyone else, as a teacher and author, he has helped introduce the technique of X-ray diffraction to the present generations of practicing metallurgists.The relevance of his contributions is demonstrated by the continuing utility of his widely translated metallurgical text, Structure of Metals, which, when it first appeared, made the understanding of metallurgy at the atomic level accessible to a wide audience. Today this book has become a compendium of first principles.

Modern Powder 15 Metallurgy Science and Technology

Powder metallurgy (P/M) has emerged as a source of new and viable manufacturing processes—with compelling economic and technical advantages over conventional ingot metallurgy practice. As well as delineating historical milestones and profiling today’s industry, this article reviews the modern approaches to powder production and consolidation from both the scientific and technological viewpoints. Some relationships between powder processing, microstructure and mechanical properties are discussed, with particular emphasis on the specialty alloys. Finally, an objective look at the interface between powder metallurgy and rapid solidification is presented.

NET SHAPE MANUFACTURING - THE UTILITY OF POWDER METALLURGY PROCESSING

Abstract Powder metallurgy is a source of new and viable near or net shape manufacturing processes, with compelling economic and technical advantages over conventional ingot metallurgy practice. Selected commercial methods are considered, namely pressing and sintering, injection molding, powder preform working and direct powder consolidation. Particular attention is directed to the prevailing state of stress, temperature and time in each mode, since these dictate densification mechanism(s), and hence microstructure and properties.

Physical Chemistry and Process Dynamics of Reactions in Ladle Metallurgy

Ladle metallurgy practices have been developed that produce clean steels low in oxygen, sulfur, phosphorous and hydrogen. In addition, the remaining inclusions can be modified into less harmful forms. In this paper, the physical chemistry and process dynamics of the refining reactions are discussed. Optimum slag compositions for desulfurization and dephosphorization based on thermodynamic considerations are given. Reaction models have been developed to predict the rates of slag-metal reaction in stirred ladles. For inclusion removal, there is an optimum gas flow rate which is explained qualitatively. The rate equations for hydrogen and nitrogen removal under vacuum are also presented.

Metastable structures in metallurgy

Metastable structures or, more accurately, configurationally frozen metastable structures are no novelty in metallurgy. Indeed, much of the traditional practice of metallurgy has centered on the formation, characterization, understanding and control of structures which are either compositionally, topologically and/or morphologically metastable. However, in the past two to three decades we have seen a great upsurge in the production and study of new metastable structures in metallurgy, as well as in other condensed phase sciences. This upsurge reflects developments in the techniques of melt quenching, condensation and irradiation of materials, as well as in the kinetic understanding of structure evolution; and it has brought us nearer to making the concept of “ultramolecular engineering” viable. Among the new materials produced are glassy metals, highly super-saturated crystalline alloys and new alloys with exceptionally high interfacial densities. An overview of these new developments will be offered, following a discussion of the principles of metastable structure synthesis.

Metastable structures in metallurgy

Metastable structures or, more accurately, configurationally frozen metastable structures are no novelty in metallurgy. Indeed, much of the traditional practice of metallurgy has centered on the formation, characterization, understanding and control of structures which are either compositionally, topologically and/or morphologically metastable. However, in the past two to three decades we have seen a great upsurge in the production and study of new metastable structures in metallurgy, as well as in other condensed phase sciences. This upsurge reflects developments in the techniques of melt quenching, condensation and irradiation of materials, as well as in the kinetic understanding of structure evolution; and it has brought us nearer to making the concept of “ultramolecular engineering” viable. Among the new materials produced are glassy metals, highly super-saturated crystalline alloys and new alloys with exceptionally high interfacial densities. An overview of these new developments will be offered, following a discussion of the principles of metastable structure synthesis.

Sintered magnesium and magnesium-beryllium alloys

The use of powder metallurgy methods for the production of magnesium alloys is highly promising. By employing technological procedures widely known in powder metallurgy practice, it is possible to make magnesium alloys whose production by the methods of melting and casting would be hardly feasible.