scholarly journals The Role of Chemical Composition of High-Manganese Cast Steels on Wear of Excavating Chain in Railway Shoulder Bed Ballast Cleaning Machine

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7794
Author(s):  
Janusz Krawczyk ◽  
Michał Bembenek ◽  
Jan Pawlik
Keyword(s):  
Chemical Composition ◽  
Cross Sections ◽  
Structural Integrity ◽  
Cast Steel ◽  
Maximum Speed ◽  
Chemical Compositions ◽  
Main Task ◽  
High Manganese ◽  
Cast Steels

The main task for a ballast bed is to transmit the sleeper pressure in a form of stress cone to the subsoil, provide proper drainage and resist the sleeper displacement. Poorly maintained ballast could severely limit the maximum speed capacity and create further problems with the structural integrity, possibly leading to a complete failure of a given rail line. To prevent the unwanted corollaries, the ballast bed has to be periodically cleaned with an appropriate machinery. In this paper the authors investigated the effect of the chemical composition on the physical properties of the ballast excavating chains made of high-manganese steels. The authors focused on the wear mechanism, work hardening ability and hardness in the cross-sections areas. A microstructure analysis was performed as well, and observations revealed divergent morphology of precipitations at the grain boundaries, which influenced the size of austenite grains. The deformation twins formed as a result of operation were noticed in the samples. Research has shown that less carbon and chromium reduces the hardness of cast steel, and it specifically affects the ability to strain hardening. The authors explained the role of adjustments in chemical composition in the operational properties of high-manganese cast steels. It has been shown in the paper that different chemical compositions affect the properties of the alloys, and this causes different types of wear. The high content of chromium increases the hardness of materials before and after plastic deformation hardening, which in the conditions of selector chains results in greater dimensional stability during wear of holes in pin joints and will be more susceptible to abrasive wear in the presence of dusts from the ballast than creep.

Influence of the Chemical Composition on the Ausferritic Transformation in Carbide-Free Bainitic Cast Steel

2014 ◽  
Vol 793 ◽  
pp. 85-91
Author(s):  
Alejandro D. Basso ◽  
Nicolás E. Tenaglia ◽  
Roberto Enrique Boeri ◽  
Juan M. Massone
Keyword(s):  
Chemical Composition ◽  
Cast Steel ◽  
Isothermal Transformation ◽  
The Other ◽  
Chemical Compositions ◽  
Transformation Kinetics ◽  
Continuous Cooling ◽  
Cast Steels ◽  
High Silicon ◽  
Kinetics Of

This work focuses on the study of the solid state transformations that take place during the austempering of high silicon carbide-free bainitic cast steels with different chemical composition. In order to get this objective three cast steel melts with different chemical compositions were produced, evaluating the influence of Cr, Mn, Ni, Al and Co. For each of these steels, samples were subjected to an austempering heat treatment at 340 oC varying the austempering time from 5 sec to 120 sec. The results show that small regions of free ferrite were obtained during continuous cooling from the austenitising to the austempering temperatures in unalloyed high silicon cast steels. At short austempering time (5 sec), the presence of a small fraction of ausferrite was observed. Austempering for 60 sec showed a larger amount of ausferrite. However, the ausferritic reaction is incomplete, and some martensite also was present, mainly located in last to freeze (LTF) zones. After an austempering of 120 sec, a fully ausferritic matrix was obtained. The addition of Cr and Mo avoided the initial precipitation of free ferrite, and lowered the isothermal transformation kinetics. On the other hand the use of Al and Co increase the presence of ferrite formed during continuous cooling and accelerates the kinetics of the ausferritic reaction.

Selection of Protective Coatings of Moulds for Castings of High-Manganese Cast Steel in Dependence of the Applied Moulding Sand Kind

2013 ◽  
Vol 58 (3) ◽  
pp. 853-857
Author(s):  
M. Holtzer ◽  
A. Bobrowski ◽  
D. Drożyński ◽  
J. Mocek
Keyword(s):  
Protective Coatings ◽  
Cast Steel ◽  
Silica Sand ◽  
High Manganese ◽  
Casting Surface ◽  
Hard Materials ◽  
Cast Steels ◽  
High Silica ◽  
Selection Of

Abstract High-manganese cast steels are characterised by a high abrasion resistance under friction conditions with a simultaneous influence of pressure and impacts. This cast steel is especially suitable for castings of excavator’s scoops, track links, streetcars crossovers, parts of crushers and mills for braking up of hard materials [1-4]. In order to obtain high quality castings of high-manganese cast steels in moulds on the high-silica sand matrices it is necessary to apply protective coatings, which prevent a direct contact between metal and matrix (SiO2). Manganese after being poured into a mould can undergo a partial oxidation forming MnO, which reacts with silica. As a result low-melting manganese silicates are formed, which in a form of a tight layer adhere to the casting surface, significantly increasing a labour input related to cleaning. Three kinds of protective coatings were tested: zirconium, corundum and magnesite. As a base moulding sands on high-silica sand matrices with three kinds of resol resins were applied. The quality of the obtained casting surface was assessed in dependence of the protective coating and resin kind and also in dependence of the metallostatic pressure value.

Evaluation of the Role of Alloying Elements in Austemperability of Heavy Section Ductile Iron

2009 ◽  
Vol 83-86 ◽  
pp. 481-487
Author(s):  
M. Heydarzadeh Sohi ◽  
Mahmoud Nili-Ahmadabadi ◽  
A. Bahrami Vahdat ◽  
A. Amirsadeghi
Keyword(s):  
Chemical Composition ◽  
Ductile Iron ◽  
Alloying Elements ◽  
Chemical Compositions ◽  
Ttt Diagram ◽  
Heavy Section ◽  
Hardness Tests ◽  
Pearlitic Transformation ◽  
Bainitic Structure

In this investigation the role of alloying elements on austemperability of heavy section ductile irons was studied. Four different chemical compositions were chosen in a way to specify an optimal chemical composition with suitable austemperability. Austempering was carried out at 315 and 350oC for 1 hour on specimens prepared from cast Y-blocks with 75 mm thickness. Metallographic examinations and hardness tests indicated that thickness of bainitic layer was positively dependant on the amount of the alloying elements which deferred pearlitic transformation in TTT diagram to the longer time. In addition, by increasing the amount of alloying elements, the morphologies of ferrite in bainitic structure changed from featherlike to acicular. According to the results of this study, in order to achieve a full bainitic structure (in the specimens whit 75mm thickness), the optimal amounts of alloying elements were: 0.35 % Mn, 0.22 % Mo, 1.1-1.4% Ni and 0.6% Cu. In addition, regarding to the thick sections of Y-blocks, graphite degeneration defect was also studied, and it was noticed that this defect could be completely eliminated by adding 50ppm of antimony.

scholarly journals The Role of Carbon in the Mechanism of Ferritic-Austenitic Cast Steel Solidification

2014 ◽  
Vol 14 (3) ◽  
pp. 83-86
Author(s):  
G. Stradomski
Keyword(s):  
Carbon Content ◽  
Cast Steel ◽  
Hot Cracking ◽  
Cast Steels ◽  
Microstructure Morphology

Abstract The paper presents the results of research on the microstructure of GX2CrNiMoCuN25-6-3-3 and GX2CrNiMoCuN25-6-3 cast steels with a varying carbon content. The cause for undertaking the research were technological problems with hot cracking in bulk castings of duplex cast steel with a carbon content of approx. 0.06% and with 23% Cr, 8.5% Ni, 3% Mo and 2.4% Cu. The research has shown a significant effect of increased carbon content on the ferrite and austenite microstructure morphology, while exceeding the carbon content of 0.06% results in a change of the shape of primary grains from equiaxial to columnar.

scholarly journals The role of gold atom concentration in the processes of formation of Cu-Au nanoparticles from the gas phase

2020 ◽  
Author(s):  
Yuri Ya Gafner ◽  
Svetlana L Gafner ◽  
Darya A Ryzkova ◽  
Andrey V Nomoev
Keyword(s):  
Chemical Composition ◽  
Au Nanoparticles ◽  
Gaseous Medium ◽  
Bimetallic Nanoparticles ◽  
Gold Atom ◽  
Dynamics Simulation ◽  
Synthesis Methods ◽  
Chemical Compositions ◽  
Atom Concentration

Currently, bimetallic nanoparticles have been widely used in various fields of nanotechnology, but the main area of their application continues to be the catalysis of chemical reactions. However, it soon became clear that the catalytic activity of nanoalloys very much depends on their size, chemical composition, and shape. Therefore, the question of controlling the synthesis of bimetallic nanoparticles to obtain particles of the desired size, spatial structure, and chemical composition is very acute. In the synthesis of the Cu-Au studied by us, nanoparticles can occur either through chemical or physical methods, each of which has its own drawbacks. Though it is very difficult to achieve the required target chemical composition of nanoparticles during chemical synthesis, their size can be stabilized quite well. In turn, physical synthesis methods mainly allow you to withstand the required chemical composition, but the size of the resulting particles varies significantly. To solve this contradiction, we studied the formation of Cu-Au nanoparticles of different chemical compositions from a gaseous medium using computer Molecular Dynamics simulation to determine the effect of the concentration of gold atoms on the size and actual chemical composition of the formed bimetallic nanoparticles.

Oxygen K near edge structures studied with multiple scattering calculations

1988 ◽  
Vol 46 ◽  
pp. 504-505
Author(s):  
Xudong Weng ◽  
Peter Rez
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Partial Cross Section ◽  
Energy Window ◽  
Edge Structure ◽  
Fine Structures ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

УКРАЇНОЗНАВЧИЙ ОСВІТНІЙ ЧИННИК В УМОВАХ СУЧАСНОЇ УКРАЇНСЬКОЇ МАСОВОЇ КУЛЬТУРИ

2019 ◽  
pp. 22-29
Author(s):  
Н. В. Фрадкіна
Keyword(s):  
Mass Culture ◽  
Personal Development ◽  
Negative Impact ◽  
Educational Process ◽  
Point Of View ◽  
Character Trait ◽  
Main Task ◽  
Leading Role ◽  
The Individual

The purpose and tasks of the work are to analyze the contemporary Ukrainian mass culture in terms of its value and humanistic components, as well as the importance of cultural studies and Ukrainian studies in educational disciplines for the formation of a holistic worldview of modern youth.Analysis of research and publications. Scientists repeatedly turned to the problems of the role of spirituality in the formation of society and its culture. This problem is highlighted in the publications by O. Losev, V. Lytvyn, D. Likhachev, S. Avierintsev, M. Zakovych, I. Stepanenko and E. Kostyshyn.Experts see the main negative impact of mass culture on the quality approach, which determines mass culture through the market, because mass culture, from our point of view, is everything that is sold and used in mass demand.One of the most interesting studies on this issue was the work by the representatives of Frankfurt School M. Horkheimer and T. Adorno «Dialectics of Enlightenment» (1947), devoted to a detailed analysis of mass culture. Propaganda at all socio-cultural levels in the form is similar in both totalitarian and democratic countries. It is connected, according to the authors, with the direction of European enlightenment. The tendency to unify people is a manifestation of the influence of mass culture, from cinema to pop. Mass culture is a phenomenon whose existence is associated with commerce (accumulation in any form – this is the main feature of education), in general, the fact that it exists in this form is related to the direction of the history of civilization.Modern mass culture, with its externally attractive and easily assimilated ideas and symbols, appealing to the trends of modern fashion, becomes a standard of prestigious consumption, does not require intense reflection, allows you to relax, distract, not teach, but entertains, preaches hedonism as the main spiritual value. And as a consequence, there are socio-cultural risks: an active rejection of other people, which leads to the formation of indifference; cruelty as a character trait; increase of violent and mercenary crime; increase in the number of alcohol and drug addicts; anti-patriotism; indifference to the values of the family and as a result of social orphanhood and prostitution.Conclusions, perspectives of research. Thus, we can conclude that modern Ukrainian education is predominantly formed by the values of mass culture. Namely, according to the «Dialectic» by Horkheimer and Adorno, «semi-enlightenment becomes an objective spirit» of our modern society.It is concluded that only high-quality education can create the opposite of the onset of mass culture and the destruction of spirituality in our society. It is proved that only by realizing the importance of cultivating disciplines in the educational process and the spiritual upbringing of the nation, through educational reforms, humanitarian knowledge will gradually return to student audiences.Formation of youth occurs under the influence of social environment, culture, education and self-education. The optimal combination of these factors determines both the process of socialization itself and how successful it will be. In this context, one can see the leading role of education and upbringing. It turns out that the main task of modern education is to spread its influence on the development of spiritual culture of the individual, which eventually becomes a solid foundation for the formation of the individual. Such a subject requires both philosophical and humanitarian approaches in further integrated interdisciplinary research, since the availability of such research will provide the theoretical foundation for truly modern educational and personal development.

An Study of Influence of Imperfections on the Delamination of Diamond-Like Carbon Films

2002 ◽  
Vol 719 ◽  
Author(s):  
Myoung-Woon Moon ◽  
Kyang-Ryel Lee ◽  
Jin-Won Chung ◽  
Kyu Hwan Oh
Keyword(s):  
Cross Sections ◽  
Focused Ion Beam ◽  
Imaging System ◽  
Ion Beam ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Glass Substrates ◽  
Atomic Force ◽  
Initiation And Propagation

AbstractThe role of imperfections on the initiation and propagation of interface delaminations in compressed thin films has been analyzed using experiments with diamond-like carbon (DLC) films deposited onto glass substrates. The surface topologies and interface separations have been characterized by using the Atomic Force Microscope (AFM) and the Focused Ion Beam (FIB) imaging system. The lengths and amplitudes of numerous imperfections have been measured by AFM and the interface separations characterized on cross sections made with the FIB. Chemical analysis of several sites, performed using Auger Electron Spectroscopy (AES), has revealed the origin of the imperfections. The incidence of buckles has been correlated with the imperfection length.

NURTURING OF CHILDREN THROUGH DRAMA AND THEATRE: THE CASE OF INTWASA KOBULAWAYO PERFORMANCES

2016 ◽  
Vol 13 (2) ◽  
pp. 86-99
Author(s):  
Vimbai Moreblessing Matiza
Keyword(s):  
Political Development ◽  
Children And Youth ◽  
Main Task ◽  
Growing Up ◽  
Theatrical Performances ◽  
History Of ◽  
The One

Dramatic and theatrical performances have a long history of being used as tools to enhance development in children and youth. In pre-colonial times there were some forms of drama and theatre used by different communities in the socialisation of children. It is in the same vein that this article, through the Intwasa koBulawayo performances, seeks to evaluate how drama and theatre are used to nurture children and youth into different developmental facets of their lives. The only difference which this article will take into cognisance is that the performances are done in a different environment, which is not the one used in the pre-colonial times. Although these performances were like this, the most important factor is the idea that children and youth are socialised through these performances. It is also against this backdrop that children and youth are growing up in a globalised environment, hence the performances should accommodate people from all walks of life and teach them relevant issues pertaining to life as they live it now. Thus the main task of the article is to spell out the role of drama and theatre in the nurturing of children and youth through socio economic and political development in Intwasa koBulawayo festivals.

SISTEM PENDUKUNG KEPUTUSAN PEMILIHAN GURU BERPRESTASI KOTA MEDAN MENERAPKAN METODE PREFERENCES SELECTION INDEX (STUDI KASUS : DINAS PENDIDIKAN KOTA MEDAN)

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Fajar Syahputra ◽  
Mesran Mesran ◽  
Ikhwan Lubis ◽  
Agus Perdana Windarto
Keyword(s):  
Decision Making ◽  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Formal Education ◽  
Basic Education ◽  
Selection Index ◽  
Main Task ◽  
Selection Of

The teacher is a major milestone in the world of education, the ability and achievement of students cannot be separated from the role of a teacher in teaching and guiding students. Based on the Law of the Republic of Indonesia No. 14 of 2005 concerning Teachers and Lecturers, in Article 1 explained that teachers are professional educators with the main task of educating, teaching, guiding, directing, training, evaluating, and evaluating students in early childhood education through formal education, basic education and education medium. Whereas in Article 4 of the Act, it is explained that the position of teachers as professionals serves to enhance the dignity and role of teachers as learning agents to function to improve the quality of national education.Decision making is an election process, among various alternatives that aim to meet one or several targets. The decision-making system has 4 phases, namely intelligence, design, choice and implementation. These phases are the basis for decision making, which ends with a recommendation.The Preferences Selection Index (PSI) method is a rarely used decision support system method. This method is a method developed by stevanie and Bhatt (2010) to solve the Multi Criteria Decision Making (MCDM). With the right consideration, this method can be one of the tools to determine policies in decision-making systems, especially the selection of outstanding teachers. Determination of policies taken as a basis for decision making, must use criteria that can be defined clearly and objectively.Keywords: Decision Support System, PSI, Selection of Achieving Teachers

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