Processing Of Metallic Materials Research Articles

Analysis of deformations of rolls in the six-high tandem mill on the basis of anti-symmetry rotation

Six-high tandem mills are widely used in the manufacturing and processing of metal materials. There are many traditional methods which can be used to calculate the deformations of rolls. Since the structures of the mills are anti-symmetry, the traditional methods are difficult to be applied. In this paper, based on the rotation of the half anti-symmetrical structures, the symmetrical structures are obtained. Through the beam theories, the deflections of the rolls are carefully analyzed. Then, the forces and moments on the rolls are also yielded and discussed in the paper. The deformations of the rolls are obtained based on a new model and they are in good agreement with the results based on finite element method. It also should be emphasized when other intermediate rolls are used, the model is also practicable with higher degree polynomials. Since the rotation method recorded in this paper is based on both geometrical and mechanical knowledge, it can be seen as a simplified way to solve the mechanical problem. From the point of model simplification, the method has a good meaning to the manufacturing.

Corrosion News

This book provides a state‐of‐the‐art overview on the processing, characterization, and modelling of metallic and ceramic materials used for energy and environmental applications. 17 scientists show a collection of current knowledge in 8 chapters. This book fulfills its intention to provide a reference book containing a collection of publications on thin films and coatings made of ceramic and metals used for energy and environmental applications. It covers a broad range of this topic and provides a comprehensive insight. Graduate and undergraduate students of materials science and mechanical engineering can find an overview on this topic to step in this interesting field of engineering.

Influencing Factors and Control Strategies of Heat Treatment Deformation of Metal Materials

In the thermal processing of metal materials, the performance of thematerial is more stable, and the heat-treated materials are processed into parts to make the performance more excellent and more in line with the performance requirements of mechanical parts. However, in thermal processing, metal materials are prone to problems, such as deformation, deformation of the appearance of metal materials, and fatal effects on the processing of mechanical parts. Therefore, this paper focuses on solving the causes of deformation in the thermal processing of metal materials, as well as solutions to improve the problems in the processing of metal materials.

Microwave Processing of Metallic Materials

The author has performed experimental studies on microwave heating of metallic materials for these twenty years. In this report, it is intended to review the researches and discuss the future prospects on this subject, from the following three points of view: 1. Separated E(Electric)/H(magnetic) field heating in a single mode cavity contributed to understanding of the microwave heating mechanisms of various materials. It was demonstrated that heating behavior of metal film depends on the substrate normal direction with respect to the microwave oscillating magnetic field. 2. In heating of metal/ceramic composite materials, its effective permittivity values have to be determined. In relation with occurrence of conductivity percolation, some measurement data are presented exhibiting negative permittivity (real part), and possible interpretation of the composites’ permittivity was discussed. 3. In microwave processing of materials, “non-thermal effect” has been proposed, so far. In this report, the non-thermal effect observed in annealing the Au thin film will be presented. And possible effect of magnetic resonance heating is proposed.

Finite Element Modeling of the Technology of Multiple Laser Shock Processing of Materials Using the Eigenstrain Method

The laser shock processing (LSP) of material is an efficient modern technology of processing of metal materials, during which significant compressive residual stresses contributing to an increase in their strength and tribological and operational characteristics are generated in the subsurface area. The finite element modeling of the technology of multiple laser shock processing is carried out using the eigenstrain method. The level of the compressive residual stresses arising under LSP is determined. It is shown that the residual stresses on the surface of the VT-6 alloy grow from 510 to 830MPa with an increase in the number of pulses from 1 to 4, and the depth of the zone of the compressive residual stresses increases respectively from 1.26 mm after the first pulse to 1.60 mm after the fourth pulse.

Features of Finite Element Modeling of Residual Stresses Arising in Material under Laser Shock-Wave Processing Using the Intrinsic Deformations Method

Laser shock-wave processing of materials is a modern technology for effective processing of metallic materials. In the near-surface region, the processing produces significant compressive residual stresses that contribute to increasing material strength and improving their tribological and operational characteristics. In this work, we performed finite element modeling of the laser shock-wave technology using the intrinsic deformation method. Specifically, using the intrinsic deformation method, we first solved the dynamic problem on the impact of a shock load and determined the distribution of stabilized plastic deformations (so-called “intrinsic deformations”) and then solved the static problem on the elastic response of the system to the intrinsic deformations induced into it. The level of the resulting compressive residual stresses arising upon laser shock-wave processing is determined. The obtained results correlated well with the known experimental data.

Life Cycle Assessment on the Effects of Parameter Setting in Direct Recycling Hot Press Forging of Aluminum

Metallic material processing plays a significant role in terms of global environmental impact which contributes to the climate change phenomena that is a serious international environmental concern and the subject of much research and debate. Thus, energy-and resource-efficient strategies in the metal shaping technology domain need to be identified urgently. A frequent theme in the debates that surround waste and resources management is the extent to which the recycling of metallic materials offers genuine benefits to the environment. Solid state recycling techniques allow the manufacture of high density aluminum alloy parts directly from production scrap. In this paper the environmental impacts associated with ‘meltless’ scrap processing routes through hot press forging process with varying parameter has been studied. A comparative analysis has been performed, with different operating temperature and holding time of direct recycling hot press forging process AA6061 aluminum chip. The importance of an environmental performance analysis that included both parameter setting was discussed and highlighted throughout the paper. Finally, the application of the proposed parameter setup has resulted in the setting up of an eco-process. Indeed, LCA study on recycling (solid-state) are recommended as well it gives a noteworthy benefit to the environment and to fill the knowledge gap.

On characterization of Microwave and Conventional Cast Bulk Brass

Corrosive resistant nature of brass makes it suitable for wide applications. Processing of bulk metallic materials using microwaves is still immature. Brass is taken in bulk form and melted using a 900 W domestic microwave applicator operating at 2.45 GHz frequency and modified with a controller attachment. As-cast and as-received brass is characterized for metallurgical and mechanical properties. X-Ray Diffraction pattern analysis shows dominant presence of copper–zinc phase in as-cast brass. Surface morphology of the prepared specimens is studied under electron microscope. Tensile strength of microwave melted as-cast brass is 350.88 MPa in an average, which shows 2.5% improvement than the conventionally melted as-cast brass. Hardness of microwave and conventionally melted as-cast brass are found to be 153.3 and 149.9 Hv respectively, while that of as-received brass is found to be 131.1 Hv. It is observed from the present work that bulk metals can be processed using microwaves, which has resulted in enhancement of the mechanical properties.

Simulation and analysis of microwave heating while joining bulk copper

Processing of bulk metallic materials using microwave energy is challenging. However, in this work microwave heating has been successfully employed for joining of bulk copper. The present work illustrates the joining process using COMSOL simulation tool. The work complements the experimental results of the microwave heating of bulk copper in a multimode microwave applicator. In electromagnetic processing, thermal dissipation in the bulk metal may be attributed to resistive heating, dielectric and magnetic losses. This dissipative mechanism is coupled to the fields by the conductivity, permittivity and permeability of the metal. The model has been created for heating of the bulk metal in a microwave oven by considering the radio frequency of the microwaves. The distributed power and heat source were computed in a stationary, frequency domain electromagnetic analysis and coupled to a transient heat transfer simulation showing the heat distribution in the bulk copper joint. The maximum power observed at the joint interface is 6.0618×108 W/m3 with an average power is 3×108 W/m3. However, the temperature will be around 1144˚C was attained in 300 s at the joint interface while the parent material is about 940 ˚C. The simulation results are in good agreement with the experimental one.Keywords: Microwave heating, FEM Model, Simulation, Copper Joint, Resistive Heating.

Understanding grain evolution in additive manufacturing through modeling

Variability in the mechanical properties of additively manufactured metal parts is a key concern for their application in service. One of the parameters affecting the above-mentioned property is solidification texture which is driven by scan patterns and other process variables. Understanding of how these textures arise in the AM process can provide a pathway to control these features which ultimately decide the final structural material properties. In this work, a Cellular Automata (CA) based two-dimensional microstructure model is formulated and implemented to understand grain evolution in AM. Grain evolution in multilayer depositions using various scan patterns in Directed Energy Deposition (DED), Metal Laser Sintering/Selective Laser Melting (MLS/SLM), and Electron Beam Melting (EBM) is presented and qualitatively compared with reported literature. Results show strong correlation of scan patterns with evolving grain orientations. Variability in grain size and orientation evolution during SLM and EBM processing of metallic materials showed direct influence by exposure to different cooling rates and thermal gradients. The similarities between the simulated and reported results lead us to conclude CA based modeling for predicting grain orientation and size in metal AM processes is useful for prediction of continuum level structural properties at global and local length scales.

Study and Assessment of the Efficiency of the Cocoa Bark Extracted from the Theobroma Cacao as an Inhibitor of the Corrosion of Carbon Steel in Substitution of Benzotriazole

Corrosion represents high losses to the economy, therefore, researches on the minimization of its damages in materials, mainly the metallic ones, are necessary. Among the various alternatives of protection against corrosion, there is the application of corrosion inhibitors that can minimize or even stop the corrosive process of metallic materials. However, at present, substances usually used as corrosion inhibitors present high toxicity, being considered harmful components to the environment and to human health. Therefore, there is an urgent need for studies on viable corrosion inhibitors, by considering not only economic but also environmental costs. The present work studied the use of cocoa bark extract (Theobrama cacao L), for possible replacement of benzotriazole (BTAH) in the corrosion inhibition of ASTM 1020 carbon steel (CS- ASTM 1020) in 18.23 g.L-1 hydrochloric acid media. Weight loss measurements, anodic and cathodic potentiodynamic polarization curves and electrochemical impedance experiments were carried out. The results showed that the addition of the extract to the electrolyte effectively hinder the corrosion process and indicated its adsorption on the electrode surface. In addition, the inhibiting efficiency of the cocoa bark extract was only slightly inferior to BTAH, showing that it can be an environmentally friendly option to toxic inhibitors.

Caracterización experimental de las emisiones de nanopartículas en el tratamiento de AA6061, AISI304 y Ti6Al4V por ondas de choque generadas por LASER

Este artículo es un estudio experimental sobre la caracterización de las emisiones de nanopartículas en el tratamiento superficial por ondas de choque generadas por LASER (LSP) de materiales metálicos: aceros inoxidables, aleaciones de aluminio y de titanio. Se confirmó que la emisión de partículas de tamaño nanométrico consiste en agregados compuestos de partículas esféricas en el rango de 10-20 nm, cubiertas por una pequeña “capa” concéntrica correspondiente a óxidos metálicos. El análisis de las nanopartículas mostró la presencia de los principales elementos presentes en las aleaciones ensayadas, y también un contenido elevado de oxígeno que corrobora la presencia de óxidos de Fe, Al y Ti. La cantidad de nanopartículas emitidas, mostró aumentos considerables sobre la línea de base medida para el ambiente de trabajo, y estos aumentos corresponden a los impulsos más intensos de LASER. Se observó que la densidad del material influí en la cantidad de nanopartículas emitidas. Durante el LSP de aleación de aluminio (el material más ligero) se midió una gran cantidad de nanopartículas, mientras que en LSP de acero inoxidable se observaron pocas nanopartículas, y este es el material más denso, entre los tres ensayados. La aleación de titanio da como resultado valores intermedios. El estudio de estas emisiones es innovador y relevante para entornos industriales donde el proceso de fabricación está en uso.

New polycrystalline modeling as applied to textured steel sheets

It has been long recognized that the preferred orientation of the grains, arising from processing of metallic materials, result in anisotropic plastic behavior. An accurate assessment of the resulting macroscopic plastic anisotropy is thus essential in predicting the mechanical performance of alloys. This paper presents a new approach for modeling polycrystalline behavior. A key aspect in the formulation is the use of the single-crystal yield criterion recently developed by Cazacu et al., 2017 for the description of the plastic properties of the constituent grains. The capabilities of the polycrystalline model in predicting the directionality of macroscopic tensile properties are illustrated by comparing the theoretical predictions with mechanical data on steel sheets of various textures. There is a good agreement between experimental and theoretical predictions.

Microstructure of Archaeological 17th Century Cast Copper Alloys

Abstract In Poland, researchers have a very strong interest in archaeometallurgy, which, as presented in classical works, focuses on dating artefacts from the prehistoric and early medieval periods in the form of cast iron and copper castings. This study, extending the current knowledge, presents the results of a microstructure investigation into the findings from the Modern era dating back to the late Middle Ages. The investigated material was an object in the form of a heavy solid copper block weighing several kilograms that was excavated by a team of Polish archaeologists working under the direction of Ms Iwona Młodkowska-Przepiórowska during works on the marketplace in the city of Czestochowa during the summer of 2009. Pre-dating of the material indicates the period of the seventeenth century AD. The solid copper block was delivered in the form of a part shaped like a bell, named later in this work as a “kettlebell”. To determine the microstructure, the structural components, chemical composition, and homogeneity, as well as additives and impurities, investigations were carried out using light microscopy, scanning electron microscopy including analysis of the chemical composition performed in micro-areas, and qualitative X-ray phase analysis in order to investigate the phase composition. Interpretation of the analytical results of the material’s microstructure will also help modify and/or develop new methodological assumptions to investigate further archaeometallurgical exhibits, throwing new light on and expanding the area of knowledge of the use and processing of seventeenth-century metallic materials.

Microstructural Investigation and Characterization of Bulk Brass Melted by Conventional and Microwave Processing Methods

Microwave processing of bulk metallic materials is an emerging area. In the present work, brass in bulk form is melted in a modified domestic microwave oven operating at 2.45 GHz frequency. As-received and the as-cast brass are subjected to metallurgical and mechanical characterization. Specimens’ surface morphology is studied under Scanning Electron Microscope (SEM). X-Ray Diffraction (XRD) pattern shows the presence of copper oxides phase in both cast brass. Average tensile strength of brass melted using microwave oven is found higher when compared with brass melted in muffle furnace. Hardness of the as-cast brass is found to be higher than the as-received brass. However, brass cast by microwave irradiation exhibits around 2 % higher hardness than the brass cast by conventional heating. Microwave melting of brass consumed nearly six times less time compared to conventional melting.

Strength and fracture of ultrafine-grained titanium Grade 4

Processing of metallic materials by methods of severe plastic deformation (SPD) provides a possibility to reduce grain sizes to nanocrystalline (NC) or ultrafine-grained (UFG) conditions. Such a structure can lead to high strength of the material, but can also reduce material ductility. The majority of papers on this topic consider deformation parameters of NC and UFG materials only for the case of quasi-static tensile tests. Parameters of fracture toughness, dynamic strength, as well as fracture processes of UFG materials remain poorly understood. However, a reduction in ductility may result in low values of important constructional strength characteristics. This reduces the attractiveness of NC and UFG materials for industrial applications. This work presents the study an influence of SPD on the constructional strength parameters and fracture character of commercially pure titanium Grade 4. The UFG structure of the material was obtained by means of equal-channel angular pressing according to the Conform scheme (ECAP-Conform) and subsequent drawing. The combination of the utilized modes of ECAP and heat treatment makes it possible to obtain the maximal known degree of ductility for the UFG titanium. Quasistatic tensile tests, impact toughness tests on samples with U-shaped notch, and fracture toughness test for the case of three-point bending were carried out. The test results of the UFG titanium showed an increase in the tensile strength by 40%, an increase in the impact toughness by 15% and a reduction in the fracture toughness by 30% as compared to its coarse-grained analog. Fracture surface corresponding to localized plastic deformation is observed for all of the performed tests.

High-speed X-ray PCI and XRD During Dynamic Fracture

When a crack or a shear band propagates in a ductile material under impact loading, there is a severe stress concentration and/or strain localization near the tip of the discontinuity. It has been understood that the locally severe and fast deformation can lead to phase transformation and heat generation. The adiabatic conditions cause the local temperature to rise. However, it has been a challenge to experimentally measure the microstructural evolution, such as crystal d-spacing, texture evolution and material phase transitions, associated with the dynamic deformation and fracture process of ductile metallic materials. It is also a challenge for optical high-speed imaging techniques to image the details of the advancing crack tip with sufficient spatial resolution. In the dynamic experiments presented in this article, we used Kolsky bars integrated with a simultaneous X-ray phase contrast imaging (PCI) and diffraction (XRD) technique to study the dynamic deformation and fracture processes during high-rate loading. In such a Kolsky bar experiment, high-speed imaging of the specimen deformation and fracture processes and high-speed X-ray diffraction are recorded simultaneously in real time. The experimental setups and results on the dynamic fracture of an aluminum alloy and a bovine tibia bone are presented and discussed.

A comparative study of mechanical and microstructural characteristics of aluminium and titanium undergoing ultrasonic assisted compression testing

The mechanism of ultrasonic softening effect has been widely investigated and used in the metal material processing area. Deficiency discussion, however, has been focused on the residual effect of ultrasonic vibration on the plasticity of metals only. In this study, ultrasonic vibration assisted compression (UAC) experiments were carried out using commercially pure aluminium and titanium samples. Despite the similar ultrasonic softening effect, different ultrasonic residual effects were observed in the aluminium and titanium samples. Aluminium exhibited a residual hardening phenomenon, whereas in titanium the initial residual hardening effect transferred to a residual softening effect with an increase in amplitude of the applied ultrasonic vibration. Electron backscatter diffraction (EBSD) characterizations revealed that substructure multiplication, texture evolution and dynamic recrystallization caused by the ultrasonic vibration are the main causes of the residual hardening effect of aluminium. The boundary strengthen mechanism based Hall–Petch relationship was used to explain the mechanism and to predict the influence of the ultrasonic residual effect for aluminium. For the titanium, it was found that the ultrasonic vibration reduced the density of deformation twinning in the specimen, and the evolution of residual effect was analysed from the aspects of grain refinement, deformation twinning induced strain hardening. By quantitative study, the main reason for the residual hardening effect of UAC aluminium sample is identified to be the ultrasonic vibration induced grain refinement, while for the titanium, the weakened strain hardening effect induced by deformation twinning should be the main factor accounting for the residual softening of titanium. Also the ultrasonic vibration could have a similar influence as that of the thermal treatment to the titanium sample, resulting in the yield point elongation (YPE) phenomenon.

Fabrication of Microalloy Nitrided Layer on Low Carbon Steel by Nitriding Combined with Surface Nano-Alloying Pretreatment

Surface mechanical attrition treatment (SMAT) is an effective method to accelerate the nitriding process of metallic materials. In this work, a novel technique named surface nano-alloying (SNA) was developed on the basis of surface mechanical attrition treatment, which was employed as a pretreatment for the nitriding of low carbon steel materials. The microstructure and surface properties of treated samples were investigated by SEM, XRD, TEM and the Vickers hardness test. Experimental results showed that a surface alloying layer (Cr element) of about 10–20 μm in thickness was formed on the low carbon steel sample after the surface nano-alloying treatment. After nitriding for the SNA sample, a complex compound layer composed of Fe2–3N, FeCr and Cr2N phases was fabricated. Moreover, the thickness of this compound layer was about 50 μm. Meanwhile, both the surface hardness and wear resistance of the SNA nitrided sample are better that those of the SMAT nitrided sample. This work offers a new approach for improving the nitriding process of steel materials.

Feasibility Study of Complex Sheet Hydroforming Process: Experimental and Modelling

The application of finite element method (FEM) in the area of metal forming and material processing has significantly increased in the recent years. The presented study provides details of the development of a finite element modelling approach to form a part via sheet hydroforming (SHF) process. Both FEM analysis and experimental trials were introduced in this study to produce a complex shape component from Inconel 718 material. The FEM provides a robust feasibility study for forming this part in terms of blank design, load path and process design optimisation. The simulated hydroformed part was validated by performing experimental trials. The analysis demonstrated close correlation between the predicted FE model and the physical trial.