Cast Structure Research Articles

Detection Method for Shrinkage Cavities Inside Spheroidal Graphite Cast Iron Using Vibration Measurement by Electromagnetic Force Excitation

The inspection of shrinkage cavities formed inside spheroidal graphite cast iron during the manufacturing process of spheroidal graphite cast products, including large cast structures and machine parts, is considered to be important for quality assurance of cast products. X-ray and ultrasonic methods are generally used for this inspection. However, the former inspection method takes a long time and considerable equipment costs, the latter method requires the use of water as a contact couplant and to polish the surface of the inspection site of the cast iron. In an actual manufacturing factory, there is a demand for a simple and quick method for inspecting shrinkage cavities inside cast iron. In this research, as a simple and high-speed inspection method to evaluate shrinkage cavities inside cast iron by measuring of the vibration of the electromagnetic force is proposed. Three-dimensional electromagnetic field analysis using the finite element method and displacement analysis was performed to analyze the phenomenon, and the usefulness of this method was confirmed by verification experiments.

Processability and structural evolution of round ingots of Al – 2 % Cu – 2 % Mn alloy during forming

This paper looks at the processability of round ingots of Al – 2% Cu – 2% Mn alloy during pressing, radial-displacement rolling and drawing. As a result of pressing combined with cross rolling, 9 mm round bars were obtained, which were then rolled and drawn into 0.5 mm wire. The wire was examined in its initial state and after different regimes of annealing. The paper shows that the cast structure contains a small amount (<2 vol. %) of eutectic particles Al2Cu and Al15(Fe,Mn)3Si2, which ensures a good deformation plasticity at the relatively low temperature of 300 oC and enables to produce 15 mm pressed round bars with a 94% reduction. In spite of considerable strain hardening, the bars displayed high processability when subjected to cold radial-displacement rolling and drawing. Thus, a 0.5 mm wire could be obtained with a total reduction of 99%. Mn-bearing dispersoids partially formed during pressing, which prevent softening during annealing. It is shown that the best combination of strength and plasticity is achieved after annealing at 350 oC, which indicates a rather high heat resistance. This experimental alloy can potentially be used as a basis for developing wrought alloys designed to produce round ingots on a commercial scale. Such ingots require no homogenization and can be used to produce a variety of deformed semi-finished products offering an optimum combination of mechanical performance and heat resistance.This research was funded under Grant No. 20-19-00249 by the Russian Science Foundation.

Influence of Caste, Education and Family on Women’s Participation in Village Panchayats of Uttarakhand with special reference to Ukhimath and Raipur Block

Women’s leadership and their effective participation is increasingly on the development agenda of governments. The gender mainstreaming and active involvement of women, who constitute almost 50 percent of population, is very crucial for the development of the rural areas. Women are still disadvantaged due to their limited access to land, credit, technology and resources. Rural women are economically backward. Poverty, illiteracy and caste are the factors affecting the social, economic and political development of woman.
 Affirmative action to ensure women’s participation in politics is an important step in democratising and engendering local governance. However, it has not been adequate to ensure women’s leadership and their effective participation in local governance, as elected women representatives. At the institutional level, the capacity of local governance structures to implement reforms, institutionalize accountability systems, decentralise functions and facilitate women’s active engagement plays a role in determining whether women are able to emerge as political actors. Social barriers include lack of education, lack of respect for women in PRIs, physical violence against women in public and domestic spheres and oppressive patriarchal and caste structures. In this paper effort has been made to analyse and understand influence of some of social factors, like caste, education and family on women’s participation in village panchayat of Uttarakhand.
 Int. J. Soc. Sc. Manage. Vol. 10, Issue-1: 5-9.

Assessment of the effect of small additions of some rare earth elements on the structure and mechanical properties of castings from hypereutectic chromium white irons

<abstract> <p>Article considers the influence of additions of rare earth elements such as Sm, La, Ce, Nd, and Y on the structure and properties of hypereutectic high-chromium white cast iron of grade G-X300CrMo27-2. To obtain an increased content of carbides in the studied cast iron samples, the carbon content was 3.75–3.9 and 4.1–4.2 wt%. The amount of rare earth elements additives added to the melt is 0.2% by weight. Data were obtained on the effect of overheating and cooling rate in the crystallization interval on the effect of rare earth additives, the structure and properties of white cast iron castings are given. According to the results of the microprobe analysis, it was shown that, under the chosen crystallization conditions, Sm, La, and Ce can form solid solutions with primary and eutectic carbides (FeCr)<sub>7</sub>C<sub>3</sub>. La and Ce form solid solutions with austenite. Nd and Y do not dissolve in iron chromium phases. All listed rare earth elements form phosphides and oxyphosphides. Experimental data are presented on the effect of rare earth elements on the size of primary (FeCr)<sub>7</sub>C<sub>3</sub> carbides and a hypothesis is proposed on the effect of rare earth elements on the crystallization process of hypereutectic chromium white cast irons. Experimental data are presented on the effect of REE additives on the microhardness of phases, hardness, strength, and resistance to abrasive wear of cast iron castings. It was found that the introduction of these additives into hypereutectic chromium white cast iron does not contribute to the modification of the structure and leads to an increase in the size of primary crystals, as well as a decrease in their mechanical properties. However, the addition of Y increases the abrasive wear resistance, but reduces the strength of castings made from such white cast iron.</p> </abstract>

The influence of cooling rate on the structure and properties of castings of hypereutectic high-chromium cast iron when they are modified with B, Bi, Sb, Sn, Ca

<abstract> <p>The article presents the results of a study of the influence of B, Bi, Ca, Sn, and Sb additives on the structure, composition, and properties of individual phases and mechanical properties of castings made of hypereutectic high-chromium cast iron (HCCI), similar in composition to G-X300CrMo27-1 cast iron. Additives of these elements were introduced into the melt before cooling at an amount of 0.2 wt.%. The ingots were obtained at a melt cooling rate in the crystallization range of 0.083–0.116 ℃/s and at 4.67–5 ℃/s. When studying the structure, the parameters and proportion of primary carbides, and the proportion of eutectic carbides were determined and a description was given of the change in the austenitic matrix. Using microprobe analysis and microhardness measurements, changes in the composition and hardness of primary, eutectic carbides and the matrix were determined. Hardness HV, bending strength, and abrasive wear resistance were determined. It has been shown that depending on the cooling rate, the effect of these additives on the structure and properties of castings changes. The mechanism of influence of these elements on the process of crystallization of primary carbides in HCCI is considered. Based on the data obtained, it is proposed to use Ca as a modifying additive when producing castings from HCCI of a hypereutectic composition under slow cooling conditions, and B under fast cooling conditions. This makes it possible to increase the wear resistance of castings.</p> </abstract>

Shungite — new generation modifi er for aluminum-silicon alloys

The issues of increasing in the homogeneity of the structure and properties of castings made of hypereutectic silumins are considered. It is shown that the use of natural shungite as a modifier makes it possible to solve this problem and provides an increase in the level of mechanical properties hypereutectic silumins by 10...15 %, which expands the possibilities of their application for engine building and makes it possible to abandon expensive nanocarbon modifiers.

The level of dysbiosis of the oral cavity depends on the type of dental prosthesis of the patient

The study involved 48 patients with the presence in the oral cavity of fixed dentures from 4 to 6 units with a service life of no more than 3 years. The samples of plaque from the vestibular surface of dentures were collected to determine the microorganisms in the gingival plaque. Bacteriological research was carried out by the multiplex polymerase chain reaction in real time using the Phemoflor 8 reagent kit. The degree of dysbiosis of the oral cavity was determined according to the classification of V. Khazanova. The results of the study of patients' samples did not reveal significant changes in the microbial landscape of the cervical areas. The total bacterial mass in the group of healthy individuals was lower than the total bacterial mass of patients in the investigated group significantly. IV degree of oral dysbiosis with a decrease in the number of lactobacilli, streptococci was characteristic of patients of denture wearers. The II degree of dysbiosis in patients with metal-ceramic structures was established. Patients who used solid cast and metal-plastic structures were diagnosed with II-III degree of dysbiosis of the oral cavity. The worst indicators were characteristic of prosthesis wearers of stamped-brazed structures. Quantitative indicators of the composition of the microbiota of the cervical areas of denture wearers have significant differences and different levels of dysbiosis of the oral cavity, depending on the type of dentures in the patients' mouth (Tab. 2, Fig. 1, Ref. 21). Text in PDF www.elis.sk Keywords.

High-Inclination Coring of Chang-63 of the Yanchang Formation in Huaqing Oilfield, Ordos Basin: Implications for Ancient Flow Direction and Fracture Orientation

A promising method is to use coring of high-inclination well to find ancient flow direction and orient tiny natural fractures in massive sandstone of sandy debris flow. Determination of ancient flow direction can reduce the number of exploration wells, and orientation of natural fractures is of guiding significance to the deployment of water injection development well pattern. In Block X of Huaqing Oilfield, Ordos Basin, the cores of Chang 63 section were obtained from Well Y through 16 coring operations, with a total length of 105 m. Cores is oriented through drilling parameters, the number of cores, the angle between the core edge and horizontal bedding, the coincidence degree of core profile and directional flame structure. Therefore, the micro-fractures on the core are directional. The ancient flow directions of sandy debris flow were restored by load casting, groove casting, groove casting and imbricate structure. Our results show that the ancient flow directions of sandy debris flows were southwest, southeast, northwest, and west from bottom to top. The front of the Wuqi Delta is the main source of blocky sandstone with the best oil-bearing property. Affected by the topography of the lake bottom, the sandy debris flow turned locally in the northeast direction, and the sandy debris flow from this direction was formed. The NEE-SWW-trending fractures formed in the Yanshanian period are most developed in the Huaqing area, which should be considered in deploying the flooding well network. The north-south micro-fractures formed in the Himalayan period can improve the physical properties of tight sandstone, which is of great significance for tight sandstone reservoirs.

THE INFLUENCE OF PARTICLE SIZES AND THE TITANIUM CARBIDE QUANTITY ON THE PROPERTIES AND STRUCTURE OF THE AL-CU SYSTEM ALLOYS

An analysis of the casting process and structure - formation mechanism of aluminum alloys of the Al-Cu-TiC system with high specific strength is performed. The advantages and features of using titanium carbide as an alloying component in order to create nanoscale composite materials (CM) are considered. The results of experiments for the production of CM with a homogeneous structure of Al+5%Cu+ TiC are shown. TiC nanoparticles in the parent melt are described. optimal size ratios and additive ratios of titanium carbide particles in the parent alloy are substantiated.

Unveiling the influence of dendrite characteristics on the slip/twinning activity and the strain hardening capacity of Mg-Sn-Li-Zn cast alloys

This work explores the correlation between the characteristics of the cast structure (dendrite growth pattern, dendrite morphology and macro-texture) and strain hardening capacity during high temperature deformation of Mg-5Sn-0.3Li-0 and 3Zn multi-component alloys. The three dimensional (3D) morphology of the dendrite structure demonstrates the transition of the growth directions from<11 2 ¯ 3>,<11 2 ¯ 0> and <11 2 ¯ 2> to< 11 2 ¯ 3> and <11 2 ¯ 0> due to the addition of Zn. The simultaneous effects of growing tendency and the decrement of dendrite coarsening rate at the solidification interval lead to dendrite morphology transition from the globular-like to the hyper-branch structure. This morphology transition results in the variation of the solidification macro-texture, which has effectively influenced the dominant deformation mechanisms (slip/twin activity). The higher activity of the slip systems increases the tendency of the dendrite arms for bending along the deformation direction and fragmentation. Apart from this, the dendrite holding hyper-branch structure with an average thickness below 20 µm are more favorable for fragmentation. The dendrite fragmentation leads to considerable softening fractions, and as an effective strain compensation mechanism increases the workability of dendritic structure.

Влияние термической обработки на микроструктуру и механические свойства сплава Al–Mg–Si–Sc–Zr с избытком Si

The paper studies the Al–Mg–Si alloy that does not contain scandium and zirconium, as well as the silicon-rich Al–Mg–Si–Sc–Zr alloy. Multistage thermal treatment was carried out for the Al0.3Mg1Si0.3Sc0.15Zr alloy, which included annealing at a temperature of 440 °C for 8 h, high-temperature annealing at 500 °C for 0.5 h, and artificial aging at a temperature of 180 °C with soaking for 5 h. The Al0.3Mg1Si alloy was annealed at 550 °C for 8 h, and then artificial aging was carried out similarly to the alloy with Sc and Zr additives. To study the fine structure, transmission electron microscopy was used. In the as-cast condition and after each stage of thermal treatment, the mechanical properties of the alloys were determined. It has been found that in an alloy doped with Sc and Zr, the formation of Al3Sc particles occurs already at the stage of formation of the cast structure. During subsequent artificial aging, the supersaturated solid solution decomposes with the formation of β" (Mg5Si6) particles improving mechanical properties. It has been found that in the scandium-containing alloy, fewer β" (Mg5Si6) particles are formed, as a result of which its strength properties are slightly worse than those of the base alloy are. Moreover, these particles are larger than in an alloy that does not contain scandium. This is explained by the fact that complete quenching is impossible for an alloy with scandium additives.

РОЛЬ ДХАРМИЧЕСКИХ ВОЗЗРЕНИЙ В СТАНОВЛЕНИИ ЮЖНОАЗИАТСКОЙ МОДЕЛИ ПРИРОДОПОЛЬЗОВАНИЯ

South Asia is the place where Dharmic religious and philosophical views (Hinduism, Buddhism and Jainism) originated and flourished. In ethnic ecology they are classified as ecophilic (friendly to the natural environment). The understanding of nature as a ‘living being’, in contrast to the Abrahamic religions, even at the early historical stages determined the originality of nature management systems in India and their relative social and environmental sustainability. Since the Painted Grey Ware culture, when the role of cattle breeding decreased, agriculture got a predominantly crop orientation. Under agrarian overpopulation, in order to avoid crises, it was necessary to somehow limit the consumption of natural resources, especially land. The social and cultural institutions that originated in the depths of dharmic views were the best way to reduce the load on natural life supporting systems. The class hierarchy of varnas, the laws of Manu with the rule ‘the hand of the artisan is always pure’, the development of a hierarchical caste structure, a rural community with a system of mutual exchange, and other institutions can be interpreted as a response to the socio-ecological crisis in a densely populated society under a relative shortage of natural resources in the main agricultural areas of South Asia. The article focuses on the formation and influence of traditional Hindu-Buddhist views on the economic and cultural patterns of South Asia, considers the ecological functions of culture, including the sacralization of natural objects. Many of the considered cultural phenomena are confirmed from the positions of present-day ecology.

Estimation of pressure effect on the crystallization process control based on a generalized theoretical model of a crystallizing metal

It is installed, that on aspects such as automation and control, liquid and/or crystallizing metal is a complex dynamic object, whose properties correspond to rheological body properties. Conclusions were made that the casting structure formation during crystallization proceeds under the influence of two main factors — heat removal to the mold wall and metallostatic pressure. Theoretical studies shown that the deformation of cast metal is carried out in order to correct defects but does not give this metal greater strength. It is established, by using the results of computational and theoretical studies that for efficient control of the crystallization process, it is necessary to calculate the solidification rate, and crystallization control can be reduced to control the metastable state interval. Keywords aluminum alloys, control, pressure, crystallization theory, mathematical model, heat flow, cooling rate

THE EFFECT OF HEAT TREATMENT ON CARBON LIQUATION IN CASTINGS OBTAINED BY CASTING GASIFIED MODELS

Carburization of the surfaces of steel castings obtained by casting according to gasified models is one of the main and most significant problems of using this casting method. In the work, experiments were carried out to reduce carbon liquation in castings made of 20GL steel with a wall thickness of 15 mm by carrying out heat treatment (normalization) in two modes, and the influence of the FIL-1 modifier (Russia) on the structure of castings was evaluated. The structures were examined before and after heat treatment. It was found that before the heat treatment, samples made of 20GL steel without a modifier have the largest carbonized layer (up to 2 mm), whereas in samples with a modifier this indicator does not exceed 0.8 mm. The optimal heat treatment mode for modified samples was established (normalization at a temperature of 950 °C and holding for 1 hour), leading to the distribution of carbon from the carbonized surface of the samples over their entire cross section, refining of the structure and its transition to an equilibrium state.&nbsp

At the Crossroads of Marriage: Experiences of Young Urban Middle-Class Women Negotiating Family and Sexuality Within Heterosexual Intimate Relationships in North India

This paper critically examines the experiences of women in heterosexual intimate relationships. It aims to understand how women negotiate social structures of family, marriage choice, and community through intimate relationships. Young women are challenging gendered power relations, traditional family structures, and marriage norms in their everyday lives. By this, women challenge the old structures of patriarchy, caste system, and control of their sexuality. A qualitative research design using in-depth interviews with 12 working women in the age group of 25–30 years who were in intimate relationships was conducted. The study was based in Delhi and done over two months in 2019. Women were selected through snowball sampling. Narrative analysis has been used to evaluate women’s experiences in intimate relationships. The narratives show the struggles and negotiations that women do for love and how these struggles are becoming a way of challenging various structures like patriarchy, caste, class, and religion. Women choose their life partners or arrange for their love marriage. Still, the choice of the partner and the idea of marriage are influenced by the broader patriarchal, caste, and class structures. The women in this study have been able to move beyond the traditional norm of arranged marriage but have still not taken the leap of choice free of the broader institutions of caste, class, and family. The paper concludes by emphasising that although women choose their heterosexual partners for marriage, their choices are still influenced by their caste, class, and patriarchal structures.

Influence of modification of the cast metal structure by solid phase particles on the nucleation of crystallization centers and their stability

The inoculation method has wide possibilities for improving the mechanical and operational properties of cast metal, which makes it possible to create artificial centers of crystallization due to the direct introduction of dispersed refractory particles into the melt. The efficiency of such particles serving as crystallization centers is due to the presence of an activated transition layer on their surface. In this regard, it is promising to use complex modification, in which activating additives are introduced into the melt together with dispersed refractory particles, which form a transition layer with the desired properties on the particles. At the same time, the features of the interaction of particles with activating additives have not been sufficiently studied. A theoretical assessment of the influence of dispersed particles on the nucleation of crystallization centers and their stability was carried out on the basis of a study of the phenomena of wetting, adsorption, and dissolution using the relationship between the critical size of additional nuclei, their wetting angle, and supercooling of the melt. It is shown that if between the particle and the cladding layer the difference in chemical potentials of the contacting phases will exist throughout the entire process, and on the surface of the complex it will have a low value of surface tension, then such a particle will be stable, which takes place during adsorption of a surface-active component from a melt. Therefore, the efficiency of melt heterogenization and modification of the cast metal structure is determined by the thermodynamic activity of the substance of the transition layer to the material of the solid phase particle. The obtained conclusions make it possible to select the composition of complex modifiers that allow controlling the structure of castings in the process of their crystallization.

Effect of heat treatment on the precipitation of Mg17Al12 in Mg-7Al alloy

Mg–7Al alloy is synthesized using a protective atmosphere electrical resistance furnace in which both the melting and casting compartments have provision for operation under a protective atmosphere. The maximum solid solubility of Al in Mg is around 12 wt% at 437 °C and is decreased to 0.1 wt% at room temperature as dictated by the phase diagram. Microstructural observation of the cast structure confirmed that most of the aluminium present in the alloy forms a eutectic β phase segregated around the grain boundaries of α-magnesium and hampered the mechanical properties significantly. To understand the precipitation behaviour, the Mg alloy is heat treated employing three sets of heat treatment cycles. The cast Mg alloy is solutionized at 420 °C for 24 hrs and then quenched in ice water at 7 °C to achieve a supersaturated solid solution (SSSS). The quenched samples are aged at 350 °C, 227 °C, and 150 °C for 8, 10, and 12 hrs respectively. The microstructure confirms that the alloy aged at 350 °C, forms continuous precipitation of β-phase whereas the alloy aged at low temperature i.e., at 150 °C forms discontinuous precipitation, while the sample aged at intermediate temperature i.e., 227 °C both the continuous and discontinuous precipitation are observed. Vickers hardness values of the solutionized sample are 48 ± 3 HV and aged at 350 °C, it is 55 ± 5 HV. At low-temperature ageing i.e., at 150 °C the hardness value is decreased to 44 ± 5 HV, whereas ageing at 227 °C, the hardness value is found 53 ± 5 HV.

Advantages of an All-Welded Freight Car Bogie Side Frame

Purpose. Railway safety during the operation of freight cars largely depends on the reliability, fatigue resistance and durability of the cast bearing elements of the three-element bogie, especially the side frames. Premature failure of cast frames occurs mainly due to undetected latent defects in the foundry. To eliminate these problems, it is advisable to develop an alternative native all-welded side frame for a bogie with an axle load of 23.5 tnf, which can be interchangeable with the cast structure. Methodology. Mathematical modelling approaches were used to determine the stress-strain state of an all-welded structure under the influence of regulated loads and to assess its strength in accordance with current national and modern world standards. Findings. Prototypes of the all-welded side frame structure were subjected to accelerated fatigue tests. The tests have experimentally proved that the cyclic durability of the developed side frame is significantly (2...4 times) higher than the cyclic durability of cast side frames. Originality. A comparative analysis of the permissible stress amplitudes in different zones of the all-welded side frame during long-term operation based on 107 load cycles in accordance with the current standard for the strength of railway cars and modern approaches to determining the fatigue resistance of welded joints showed the insufficient conservatism of the national standard for assessing the fatigue strength of welded joints, which was taken into account when developing a new design of the all-welded side frame. Practical value. In addition to increasing reliability, possible increase in overhaul mileage and warranty period of side frames by ensuring a high level of fatigue resistance and durability, the welded structure can ensure the accuracy of the base frame size, reduce the weight of unsprung masses, which should reduce wheel wear and improve the running characteristics of railway carriage bogies. Reducing the cost of introducing all-welded side frames into mass production compared to the use of foundry technology for the manufacture of these structures and the fact that the cost of manufacturing an all-welded side frame is generally competitive with a cast structure is also one of the important advantages of our developme

Historiographical Context of the Nayak Period

The linguistic, literary, political, social, and cultural contexts of that state greatly contribute to the need to know or write the history of a state from its rise to its fall. Historiography approached in these contexts is not only focused on the rulers but also on understanding the history of the people. This article examines how the linguistic, literary, political, social, and cultural contexts of the time contributed to the historiography of the Nayak period centred on this hypothesis. In this way, the language environment where Tamil and other languages are mixed, the literary environment about changes in literary forms as a result of contact with other languages, the political environment of the Nayaks who supported the Vijayanagar regime and then fell apart due to rivalries and struggles, the social environment about conflicts in society with inequalities and caste structures, and the cultural environment about customs as a result of neighbouring settlements are all intertwined.

Outsider at home: Reading Babasaheb Ambedkar as a radical, decolonial psychologist.

Known primarily as the architect of the constitution of India, Babasaheb Ambedkar was also a human rights lawyer, an economist, a social justice advocate, and a polymath. Yet his story is often overlooked in favor of national leaders such as Gandhi. This study highlights Ambedkar as a visionary who called for a radical and new psychology of self that was anchored in ideas of social justice, equity and full participation. Furthermore this study fills the gap in the field of psychobiography which rarely reflects the cultural lives and experiences of the Global South. This study follows the psychobiographical method and uses memoirs, essays, speeches, and biographies as data. Three "turning points" in Ambedkar's life are examined: (1) Early childhood experiences of being an "untouchable"; (2) Returning to India for employment after completing his doctorate in the U.S.; (3) Converting to Buddhism in later life. Using a decolonial theoretical lens, we analyze the multiple ways that he experienced being colonized and dehumanized. As he defied the caste structures within his own culture and resisted colonialism, Ambedkar developed a syncretic politics of resistance that emphasized the creation of a decolonized Dalit self and community.