Field Of Metallurgy Research Articles

Harmonic Vibration Control Synchronization Simulation for Double Exciting Motors of Single-Mass Nonlinear System

For nonlinear harmonic vibration synchronization vibration machine have been widely used in metallurgy, mining, agriculture and other fields, but the harmonic vibration synchronization mechanism for the multi-excitation sources which used to driven the nonlinear vibration machine to realize the harmonic vibration synchronization movement is not clear. In order to study the problem, the nonlinear electromechanical coupling dynamic model has been established for the single-mass harmonic vibration synchronization nonlinear machine in the paper, and by analyzing the coupling dynamic characteristics of the double exciting motors, the harmonic vibration control synchronous simulation model and corresponding harmonic vibration control synchronization strategy have been established. Under the different initial conditions and different Working conditions, the harmonic vibration control synchronization process for the double exciting motors have been simulated. Based on the simulation results, the harmonic vibration control synchronization mechanism for the double exciting motors which used to drive the nonlinear vibration machine have been analyzed and discussed, and the validity of the harmonic vibration control synchronization strategy for the double exciting motors to realize the harmonic vibration synchronization movement has been verified. All these can provide the reference basis for the subsequent nonlinear vibration machine to carry out the harmonic vibration synchronization status application.Introduction

Orio Malipiero’s and Enrico Dandolo’s denarii: surface and bulk characterization

From the ninth century to the second half of the twelfth century, the Venetian coinage had lost around the 90 % of its silver content. This severe debasement is a very fascinating feature for the history of numismatic and for microchemical investigations in the field of metallurgy. The significant increase of numismatic studies based on sophisticated analytical methods has further highlighted the potential of coins as a historical document [1–3]. In the present study, 50 Venetian coins, the so-called denarii, 30 issued by the Doge Orio Malipiero and 20 by the Doge Enrico Dandolo, have been examined. A multidisciplinary approach, focused on the characterization by metallographic techniques, Energy-dispersive X-ray fluorescence (EDXRF), Scanning electron microscopy (SEM) with

Study on the Surface Roughness of Titanium Alloy Machined by WEDM

Due to the excellent characteristics of titanium alloy, was applied to aviation, marine, automotive, metallurgy, medical equipment and other fields. However, some of the characteristics make it machine difficultly, so the range of applications would be limited. In this paper, titanium alloy is cut by wire electrical discharge machining (WEDM) and study the surface finish. The model of surface roughness is established which is based on theoretical analysis. Experimental results were analyzed and optimized by the theory of signal-to-noise ratio and grey relational analysis (GRA) method. The minimal surface roughness is achieved by the optimal results .According to GRA, get the order that is the influence of electric parameters on the surface roughness.

Call for Standardization in Material Behavior Assessment Systems Output Formats

The paper will present the DaCoTraP project in development that contains the critical part that requires the standardization support. Then a few experiment types will be detailed and we try to offer a solution to the problem. To define a generic mechanism that extracts specific parts of differently structured data, in our case experiment data, requires the invention of a new markup language. Fortunately such a language exists since 1950, it is very powerful and well documented [1] and it is used to manipulate text and data. Unfortunately this language is extremely complex and we cannot expect the users of the system, who are mostly lab assistants with training only in the field of metallurgy and with no programming experience at all, to define these patterns by themselves. If the experiment results were defined in files with strict and standard formatting rules, a very rigid and simple toolset could be defined and put to the users‟ disposal. 2. DACOTRAP PLATFORM

Fabricación y caracterización de aleaciones porosas de Ti y Ti6Al4V producidas mediante sinterización con espaciador

Titanium is well-known to be a biocompatible material with good corrosion properties and good strength, taking into account their low specific weight. In powder metallurgy field, titanium has been used in order to obtain porosity materials for biomedical applications. Recently, porous materials have been investigated for their use like hips implants. The principal reason is based on a reduction of stiffness implants, minimizing effects of stress shielding. The purpose of the present work is produced porous materials by space holder technique using ammonium bicarbonate like spacer. Scaffolds of titanium have been fabricated by powders of titanium with different grades of particle size and compacting pressure. Before sintering, stability of green parts has been studied by mechanical test. After sintering, porosity has been evaluated besides mechanical properties and elastic modulus by three points bending test. The microstructural characterisation is performed by optical and electron microscopy.

Thermal diffusivity, viscosity and prandtl number for molten iron and low carbon steel

This paper investigates fundamental properties of liquid iron as well as molten low carbon steel. Scope of this work is to formulate simple, even if approximated, equations useful to simulate heating and solidification processes. Attention is paid first to thermal diffusivity which is determined using known empirical equations (density, free energy and electrical resistivity) and well-accepted relationships like the Wiedemann-Franz-Lorentz law. Then, viscosity is estimated from a multiple linear regression analysis of available data. In such a way an estimation of Prandtl number is calculated. The proposed equations are tested by comparing with existing data. Such modelling may be useful for simulations in the field of process metallurgy, in steelmaking industry and also in some more recent manufacturing technologies such as selective laser and electron beam melting, when experimental values of the physical parameters are missing.

Understanding the effect of inert support on the reactivity stabilization for synthetic calcium based sorbents

The decay of sorbent reactivity in multiple carbonation/calcination cycles is a critical problem for calcium looping. By introducing inert support materials into CaO particles, the cyclic reactivity of calcium based sorbent could be drastically improved. However, there is a lack of understanding of the interaction between the CaO grain and the support material; thus, much of studies of synthesizing calcium based sorbents are by trial-and-error. In order to understand the possible mechanism of synthetic calcium based sorbent, the widely accepted Zener pinning theory in the field of metallurgy was used here to describe the inhibition of CaO grain sintering due to the addition of inert support. A simple model of CaO grain growth for synthetic calcium-based sorbents was developed to analyze the effect of inert support on the stabilization of cyclic reactivity of CaO. The mechanism of sintering resistant in the synthetic calcium-based sorbents was the pinning force exerted by the dispersed support particles. The inhibition effect of inert support on CaO grain growth is related with the grain migration due to surface energy (γ), support size (r) and volume fraction (f), and the interaction (Finteract) between the support and CaO. The model was validated with the published data and can predict reasonably the experimental results, and the relative importance of some elementary steps was discussed. This study will provide a theoretical understanding for the further development and reactivity improvement of synthetic calcium-based sorbents.

Research on the Parametric Design of Involute Helical Gear Based on Pro/Program

Involute helical gear has advantages of larger overlap coefficient, steady transmission, lower impact and noise, higher load bearing capacity, longer life, so it is widely used in machinery, mining, metallurgy, aerospace and other fields. However, due to the involute helical gear tooth profile shape is more complex, and some low-level CAD software is difficult to directly generate a three-dimensional helical gear tooth profile. According to involute helical gear formation principle, this paper presents an effective method to establish the three-dimensional model for involute helical gear .In this paper, a parametric design method of realizing involute helical gear 3D model by using Pro/E modeling functions and Pro/Program programming is discussed. This method can enable designers to obtain helical gear 3D solid model quickly and accurately by inputting a little geometry characteristic parameters. It can also enables designers quickly update design based on the existing 3D gear model, so as to improve the design efficiency.

New Solution to Surface Temperature of Casting Slab Measurement Based on Preceded Reflector and Multi-Wavelength

The surface temperature of casting slab is an important parameter in the metallurgy field. Because the surface emissivity is uncertain and also unknown, it is difficult to measure the slab surface temperature accurately. A method based on preceded reflector and multi-wavelength was put forward to deal with the difficulty in surface temperature measurement of casting slab. On the premise of preceded reflector and non-preceded reflector, the method establishes the radiation energy equations and works out the emissivity and temperature in the equations. Also, the multilayer modeling of casting slab surface and multiple reflection-absorption process modeling were built by Monte Carlo method. The temperature measuring method had been applied in the continuous casting field. In order to verify the measured result, the thermal imaging method was adopted when the slab surface emissivity was set by repeated tests. Finally, the measured and verified temperature curves keep a same tendency and the error of the values is lower than 5°C. The comparison result shows that the method can measure temperature accurately.

Research on On-Line Surface Defect Detection for Steel Strip Based on Sparse Coding

In the field of metallurgy, surface defects detection for steel plate based on machine vision is a new key technology. In order to improve the accuracy and speed of machine vision in real-time surface defects detection, taking into account the neurons selectivity and sparseness to visual information, we present a flexible data selection mechanism in the layer of photoreceptors and a new sparse coding model for object feature representation and object recognition. Experiments show that the new method is more effective and more effective in the process of training and classification. The key finding of this study is that, the effective sparse coding mechanism not only could have occurred in the data input stage, but also could be in a new way.

Distributed Architectures for Controlling Visual Guided Flexible Forging Robotic Cells

Improvements on the fields of automation, robotics and artificial vision make possible the implementation of automatic vision guided robotic cells with increasing performances for lower prices while the demands of the economical international markets demand that automatic cells with these characteristics be implemented and used at the highest possible output. This paper presents the implementation of such a cell in the hot forging field of metallurgy.

Experimental Study on High-Speed Turning of Free-Cutting Steel AISI 12L14 Using Multi-Layer Coated Carbide Tools

AISI 12L14 as a typical free-cutting steel has been widely employed in machinery, energy and metallurgy fields due to its excellent machinability. This research was concerned with the experimental investigation on high-speed turning of AISI 12L14 in terms of cutting force and tool wear with multi-layer (Al2O3/TiCN) CVD coated carbide tool. Results showed that: Depth of cut ap had the dominant effect on the main cutting force, and feed rate f followed. Increase of cutting speed vc was observed to decrease the turning forces. Optimal factor level combination (vc=500m/min, f=0.05mm/r and ap=0.5mm) was obtained through the method of extremum difference analysis. The cutting tool was observed to form sulfide lubricant zone along its rake and flank faces. Ascribed to the presence of sulfide lubricant zone the tool can obtain excellent protection and minor flank wear in the entire turning process. Crater wear was observed occurring on tool rake face and no BUE was found along the cutting edge. In addition, tool flank face suffered abrasive wear and adhesive wear.

The Hydrometallurgical Extraction and Recovery of High-Purity Silver

With the continuous reduction in the availability of extractive metallurgical curricula in colleges and universities, the concern has in part been from where will the next generation of extractive metallurgists come? One objective of this article is to emphasize the fact that extractive metallurgy is, in fact, one of many areas of chemical engineering technology. Thus, although the extractive metallurgist may have disappeared in name, its activity is alive and well, subsumed in the field of chemical engineering. One goal of this lecture is to demonstrate the applicability of chemical engineering principles to what is typically considered “the field of extractive metallurgy.” Two processes will be described that have supplanted typical pyrometallurgical fire refining of precious metals, particularly silver. The origins of fire refining can be traced back to biblical times. There are numerous references to it in the old testament: Ezekiel 22:20, “As men gather silver and bronze and iron and lead and tin into a furnace to blow the fire upon it in order melt it”; Jeremiah 6:29, “The bellows blow fiercely; the lead is consumed by the fire; in vain the refining goes on”; and Malachi 3:2 (The Oxford Annotated Bible with the Apocrypha), “For he is like a refiners fire.” Many references to it will also be found in “De Re Metallurgica” and as well in Lazarus Ercker’s 1574 Manual “Treatise on Ores and Refining.” Today, fire refining has been improved greatly by innovative furnace design, new fluxing technologies, and the improved use of oxygen. However, fundamentally, the process chemistry has not changed much in the last millennium. Illustrations of hydrometallurgical processing of silver-bearing inputs will be provided by the treatment of sulfated silver-bearing materials and chlorinated slimes. The first of these technologies will be described briefly as practiced by the Phelps Dodge Refining Corporation for several years. The second, the treatment of silver chloride-bearing inputs, will be described in detail to demonstrate how typical chemical engineering unit process and unit operations have supplanted classic smelting and fire refining techniques. The Kennecott Copper Company, which has operated a hydrometallurgical circuit successfully for the recovery of high-purity silver from the slimes wet chlorination residue, has permitted me to provide some operation information and results using the technology. Both Phelps Dodge and Kennecott should be recognized for their forward-looking attitude in undertaking the conversion of conceptual chemistry into successful, full-scale plants. The process as employed at Phelps Dodge is discussed at length in reference (J.E. Hoffmann and B. Wesstrom: Hydrometallurgy, 1994, vol. 94, pp. 69–105).

溶接冶金分野におけるシミュレーション・モデリング技術

溶接冶金分野におけるシミュレーション・モデリング技術

Slag Thickness in Continuous Casting Tundish Measuring Method Based on Temperature Information

Acquiring the thickness of slag layer in continuous casting tundish accurately is beneficial to continous casting stably, and improves enterprise benefit. A new method to measure the thickness of slag layer in continuous casting tundish, based on temperature information is put forward in the papers. A measuring bar, made of Refractory Material, was inserted into the tundish to perceive the temperature. Then the thickness of slag layer may be obtained accurately by temperature interface between air layer and slag layer, and slag layer and molten steel layer. After applying to the slag layer thickness measurement in steel metallurgy field, it has a favorable application prospects because of the measuring error about less than 2.6mm.

Slag Thickness in Continuous Casting Tundish Measuring Method Based on Temperature Information

Acquiring the thickness of slag layer in continuous casting tundish accurately is beneficial to continous casting stably, and improves enterprise benefit. A new method to measure the thickness of slag layer in continuous casting tundish, based on temperature information is put forward in the papers. A measuring bar, made of Refractory Material, was inserted into the tundish to perceive the temperature. Then the thickness of slag layer may be obtained accurately by temperature interface between air layer and slag layer, and slag layer and molten steel layer. After applying to the slag layer thickness measurement in steel metallurgy field, it has a favorable application prospects because of the measuring error about less than 2.6mm.

Application of artificial neural networks for feature recognition in image registration

Image registration is a process of aligning two or more images taken at different times or using different sensors by transforming the same area into one coordinate system. Imaging conditions, image and area deteriorations from repeated sectioning, are serious impediments to successful image registration. The application of artificial neural networks for feature recognition is introduced to the field of metallurgy to assist in an automated approach to image registration of metallurgical microstructures. Low susceptibility to feature deterioration, often occurring during serial sectioning, is demonstrated and assessed. The process of image registration using an artificial neural network to aid in feature segmentation is performed using computer generated shapes and a metallurgical microstructure.

Automated SEM/EDX Particle Analysis to Determinate Non-Metallic Inclusions in Steel Samples: Round Robin Tests Aiming at Studying the Comparability of Results from Different Measurement Systems

Abstract The use of automated measurement methods which combine scanning electron microscopy and energy dispersive X-ray analysis in order to carry out quantitative particle analyses allows for an exact characterization of the level of purity in steel in the context of aiming at ensuring a high-quality final product as well as deepening the knowledge of different steps of production in the field of metallurgy. As there is still a lack of standardization when it comes to the examination method, deviations in measurement results are possible. These can lead to reproducibility problems and limited comparability. Within the subcommittee for metallography of the ASMET a working group has been established in order to carry out a round robin test to clearly identify problems of these measurement methods and to propose and/or implement possible solutions. Four different laboratories participated in the round robin test, all of them using different measurement systems to characterize inclusions. These examinations resulted in the definition of measures to possibly standardize measurements (setting of equivalent measurement parameters, using a calibration standard for the setting of gray values). This led to reaching a good agreement of results when comparing the registered morphological and chemical values of all participants and it emphasized the great potential of the method to reach reproducible and generally usable data.

MHD stagnation‐point flow towards a shrinking sheet

PurposeThe purpose of this paper is to theoretically investigate the steady two‐dimensional magnetohydrodynamic (MHD) boundary layer flow over a shrinking sheet. The effects of stretching and shrinking parameter as well as magnetic field parameter near the stagnation point are studied.Design/methodology/approachA similarity transformation is used to reduce the governing partial differential equations to a set of nonlinear ordinary differential equations which are then solved numerically using Keller‐box method.FindingsThe solution is unique for stretching case; however, multiple (dual) solutions exist for small values of magnetic field parameter for shrinking case. The streamlines are non‐aligned and a reverse flow is formed near the surface due to shrinking effect.Practical implicationsThe flow due to a stretching or shrinking sheet is relevant to several practical applications in the field of metallurgy, chemical engineering, etc. For example, in manufacturing industry, polymer sheets and filaments are manufactured by continuous extrusion of the polymer from a die to a windup roller, which is located at a finite distance away. In these cases, the properties of the final product depend to a great extent on the rate of cooling which is governed by the structure of the boundary layer near the stretching surface.Originality/valueThe present results are original and new for the MHD flow near the stagnation‐point on a shrinking sheet. For shrinking case, the velocity on the boundary is towards a fixed point which would cause a velocity away from the sheet. Therefore, this paper is important for scientists and engineers in order to become familiar with the flow behaviour and properties of such MHD flow and the way to predict the properties of this flow for the process equipments.

The 6th European metallurgical conference EMC 2011: Proceedings review

The GDMB Society for Mining, Metallurgy, Resource and Environmental Technology organized the 6th European Metallurgical Conference (2011) in Duesseldorf from June 26 to 29, 2011. The same venue hosted the most important international metallurgical trade fairs for metallurgy of iron and steel, new casting and thermochemical processes METEC, GIFA, THERMOPROCESS and NEWCAST. The previous European metallurgical conferences were organized by GDMB in Friedrichshafen (2001), Hanover (2003), Leipzig (2005), Duesseldorf (2007), Innsbruck (2009). The GDMB is a non-profit organization situated in Clausthal in Germany, which is related to combining science with the practical experience in metallurgy, mining, materials engineering, mineral processing, recycling and refining of metals, and manufacturing of semi- and finishing products. The European Metallurgical conference EMC is one of the most known conferences worldwide in the field of non-ferrous metallurgy and is attended regularly by the decision makers from the industry and universities. The scientific program contained 6 plenary lectures and more than 160 presentations from 40 countries in 5 parallel series. An extensive poster exhibition was held, during which the authors had an opportunity to introduce their posters to the entire plenum as a part of a brief presentation. The best poster from the Montan-University in Leoben, Austria, was awarded the € 500 'Poster Award EMC 2011'. Not only were the most important European countries represented here, more than one third of the lecturers were from the non-European countries (Canada, Japan, China, USA, South Africa, Australia). The origin of the participants reflects the aim of the organizers: to make this conference a worldwide platform for the scientific exchange of experience and information. More than 400 participants from all over the world participated at this conference. The scientific presentations of the conference are presented in five Proceedings: Vol. 1: Copper, General Pyrometallurgy, Vessel Integrity, Process Gas Treatment; Vol. 2: Lead and Zinc, Process Control, Process Modeling, Vol. 3: Light metals, General Hydrometallurgy, Precious Metals; Vol. 4: Process Metallurgy, Recycling, Waste Treatment and Prevention, Vol 5: Sustainable technologies, Sustainable of non-ferrous metals production, waste effluents Treatment and Biohydrometallurgical application. The plenary lectures will be published in the scientific journal 'World of Metallurgy - ERZMETALL', which is published by the GDMB.