Metallurgical Engineering

Penelitian ini membahas berbagai aspek teknis dalam industri manufaktur modern, khususnya terkait efisiensi sistem perpindahan panas, proses pemutihan serat, penggunaan pati dalam industri kertas, pencucian lumpur kapur, dan analisis penyebab sheet break dalam produksi kertas. Studi mengenai penukar panas menyoroti efektivitas desain heat exchanger tipe shell and tube, dengan fokus pada peningkatan kinerja dan mitigasi kontaminasi termal. Pada proses pemutihan serat, penelitian ini mengevaluasi dosis optimal NaOH dan durasi retensi yang menghasilkan peningkatan kecerahan serat sebesar 5%. Dalam industri kertas, perbandingan antara Native Starch dan wheat starch menunjukkan bahwa Native Starch memiliki kinerja lebih baik dalam meningkatkan kualitas kertas. Selain itu, analisis pencucian lumpur kapur mengungkap bahwa perbandingan air 1:5 dapat mengurangi kandungan alkali hingga 0,6% dan meningkatkan dryness hingga 64,53%, yang berpotensi menghemat biaya operasional industri. Sementara itu, penelitian terkait sheet break di PT. A menggunakan metode Statistical Process Control (SPC) dan Failure Mode and Effects Analysis (FMEA), mengidentifikasi paper tear dan holes paper sebagai penyebab utama. Hasil analisis menunjukkan perlunya perbaikan berkelanjutan untuk meningkatkan efisiensi produksi. Secara keseluruhan, penelitian ini memberikan wawasan komprehensif terhadap optimalisasi proses manufaktur untuk meningkatkan efisiensi dan kualitas produk.

The coking process is based on the transformation of coal into coke at high temperature. In non-recovery coke oven, heating is usually asymmetric, this may be due to the fact that heating is provided by controlled combustion of volatile matter of charged cake at oven crown and sole flue.In the present investigation, a simp lified temperature profiles were simu lated to typical temperature pro files of the non-recovery coke oven. The selection criterions of ovens were based on the oven temperature and coking time. Based on measurement of heating pattern, a numerical methodology was proposed for predicting temperature of the intermed iate point by using Lagrange interpolation method. Further, a MATLA B-based algorith m was used to predict the same heating pattern based on actual temperature profile in a non-recovery oven. The model was tested and validated with actual temperature profile of six industrial ovens. The model also reproduces the main feature of the measured temperature profile and shown good agreement with experimental data of industrial oven. The pred icted temperature pro file can discriminate d ifferent operating conditions and works well even at low level of temperature deviation. These variations will affect the heating rate and coking cycle, superimposed on the oven crown and sole temperature pattern. However, the operating temperatures were the most important factor fo r normal operation and found that the heating rate of normal operation was varied in the range of 1.06 -0.62℃/ min at a height of 200mm fro m top & bottom and centre of the charged cake.

Various degradation mechanisms are characterized in gas turbine rotor blades due to service conditions such as: high temperature and stress. Failure of turbine blade can have the tremendous effects on the safety and performance of the gas turbine engine. This paper investigates a first stage turbine blade failure in a 6.5 MW gas turbine. The blade is made of nickel-based superalloy, and the failure occurred in the airfoils after 6500 h of operation. Several examinations were carried out in order to identify potential failure reasons such as: visual examination, fractography and microstructural characterization used by optical and scanning electron microscopes (SEM) and energy dispersive X-ray (EDX). The precipitated phases morphology (carbides and γ′ (Ni3Al)) changed in the airfoil for example γ′ resolved and re-deposited in addition to decomposition of carbides. Furthermore, the fracture surface exhibits the local melting occurred and re-solidified in the leading edge. From analysis and experimental results of this study, overheating is shown to be the main reason of blade failure.

Ushbu maqolada temirni rudadan biogidrometallurgik usulda
ajratib olish texnologiyasi ko‘rib chiqilgan. Jarayon anaerob bakteriyalar yordamida
temirning noeruvchan Fe³⁺ shaklini eruvchan Fe²⁺ shaklga aylantirishga asoslangan.
Bakteriyalar organik moddalar metabolizmi natijasida karbonat angidrid hosil qilib,
eritmadagi temirning eruvchanligini oshiradi. Maqolada karbonat angidridni
eritmada ushlab turish orqali temirni yuqori samaradorlik bilan eritmaga o‘tkazish va
eritmani tozalash bosqichlari haqida ma’lumot berilgan. Elektroliz yordamida metall
temirni eritmadan ajratib olish usuli ham o‘rganilgan. Ushbu texnologiya an’anaviy
yuqori haroratli usullarga nisbatan ekologik xavfsizroq va energiyani tejaydi, ammo
jarayonning sekinligi va qo‘shimcha xarajatlar iqtisodiy samaradorlikka ta’sir
ko‘rsatadi. Bu maqola biogidrometallurgik usulni sanoat miqyosida qo‘llash
imkoniyatlarini ko‘rsatib, past sifatli rudalar va chiqindilarni qayta ishlashda yangi
imkoniyatlar yaratadi.

Historicamente, os cerâmicos são uns dos materiais mais antigos do mundo, em virtude do seu emprego desde a pré-história. São compostos inorgânicos formados por elementos metálicos e não metálicos, ligados através de ligações iônicas e/ou covalentes. As propriedades destes materiais são determinadas pelo tipo de ligação atômica, seu caráter amorfo ou cristalino, bem como pelos métodos de seu processamento. São caracterizados por apresentar propriedades tais como: resistência a altas temperaturas e a corrosão, dureza, são isolantes térmicos e elétricos.
Cerâmicas a base de argilas, como peças decorativas, louças de mesa e relacionadas com a construção civil (louças sanitárias, cimento, tijolos, revestimento de piso ou parede), são classificadas como cerâmicas tradicionais. São elaboradas a partir de materiais naturais (ou pouco beneficiadas), de pureza variável, e com pouca exigência de controle em seu processamento.
As cerâmicas avançadas ou cerâmicas de Engenharia são produzidas a partir de matérias primas sintéticas (óxidos, nitretos, carbetos e outros) ou beneficiadas industrialmente, com alto grau de pureza, e processamento controlado rigosamente. Estas cerâmicas são utilizadas em aplicações tecnológicas, estando presentes nas indústrias de componentes eletrônicos, de comunicação, automotiva, naval, aeroespacial, biomédica, e em muitas outras áreas industriais.
Tendo em vista a importância dos materiais cerâmicos ao promover um resultado significativo na sociedade, visto que estão presentes em diferentes aplicações indústrias, este livro apresenta diferentes pesquisas relacionadas a estudos originais e de revisões bibliográficas na abordagem dessa área da ciência e engenharia de materiais.

Hydrated alu mina fro m three different sources like sodium alu minate liquor, waste alu miniu m dross and synthetic salt like alu miniu m sulfate were studied to obtain various form of alu miniu m hydro xide. Boeh mite (A l 2 O 3 .H 2 O), a form of hydrated alu mina, has better performance in obtaining alu mina, as the enthalpy of dehydration of boehmite is less as compared to gibbsite due to the less number of water mo lecules in the crystal lattice as compared to gibbsite. Precipitation of hydrated alumina was also studied by using synthetic alu miniu m sulfate solution with aqueous ammonia and alternating the sequence of reagent addition. Subsequently, the variation in the p H of precip itation and fo llo wed by variat ion of the ageing temperature produced a range of hydrated alu mina with different phases and crystallin ities. In another option hydrated alu mina was precipitated fro m the sulfuric acid leach liquor of waste aluminiu m dross by varying the pH of the precipitation followed by temperature o f ageing.

İnsanlık, belki de var olduğu ilk günden bu yana, hep bir şeyleri merak etmiş, incelemiş ve bulduklarıyla yetinmeyip araştırmaya devam etmiştir. Hiç bitmeyen bu merak ve araştırmalar sonucu bulduklarına yenilerini eklemiş ve teknoloji kavramının ortaya çıkmasını sağlamıştır. Ekonomideki gelişimlerin başlıca temel dayanağını teknolojik yeniliklerin sunmuş olduğu fırsatlar oluşturmaktadır. Malzeme teknolojisi açısından teknolojik gelişmelerin ilk basamağını malzeme özelliklerinin incelenmesi teşkil etmekte ve bu özellikler diğer bir tabir ile davranışlar malzemelerin içyapılarından etkilenmektedir. Malzeme içyapıları imalat esnasında uygulanan ısı ve deformasyondan etkilenerek değişim gösterebildiklerinden, imalat süreci sonunda malzeme özellikleri başlangıç malzemesinden ya da tasarımda dikkate alınandan farklı olabilmektedir. Bu çalışmada, çeliklerin sıcak yığma işlemi esnasında ve sonrasında mikro yapı değişimlerine ait literatürde bulunan ve kabul edilen malzeme modelleme kriterleri incelenmiştir. Ardından 1040 çeliği üzerinde yapılan çeşitli sıcaklıklardaki sıcak yığma deneyleri sonrasında numunelerin sertlikleri, mikro yapı görünümleri incelenmiş, sonuçlar modellemeler ile karşılaştırılmış ve irdelenmiştir. Öncelikle tüm yaşamım boyunca kararlarımın doğruluğuna inanıp bana olan desteklerini hiç esirgemeyen aileme; bilgi, deneyim ve sabrı ile bana rehberlik eden danışman hocam Sayın Doç. Dr. Şafak YILMAZ' a ve varlıkları ile hayatıma anlam katan arkadaşlarım Görkem KIZILTAN, Emrah DENİZ ve Nur PEHLİVANOĞLU' na teşekkürlerimi sunarım.

The Vanadis ® 8 is a tool steel used in the manufacture of dies, punches and tools. It has a high carbon content combined with chromium, molybdenum and vanadium, and presents good performance in its mechanical properties. Usually, its chips obtained by machining are sold to companies that use remelting. However, this technique is considered expensive and harmful to the environment. Therefore, this work aimed to analyze the efficiency of the addition of vanadium carbide (VC) and molybdenum carbide (Mo 2 C) in the high energy ball milling of the Vanadis ® 8 steel. Microstructural analysis were performed in the pure steel and with 3% of VC and Mo 2 C additions. The milling parameters used were: speed of 350 rpm, ball-to-powder weight ratio of 15:1 and times of 4, 8 and 12 hours. The results indicated that the Vanadis ® 8 steel milled with VC presented the best microstructural results in all of the conducted tests.

In this paper we investigate flow phenomena related to tapping of silicon melt from a submerged arc furnace. The multiphase flow model predicts how the gas pressure variations inside the furnace crater zone may effect phenomena like the gas flow pattern inside different zones of the charge materials inside the furnace, the metal tapping flow rate, and the gas blow out from the furnace tap hole. The full 3D multiphase flow model of the furnace is based on the real geometry and the most probable physical properties of different zones in the furnace, such as density, charge material particles size, porosity and permeability of the packed beds on the furnace bottom. In addition different spatial arrangements of charge material zones have been investigated. The results of the model show that existence of the mentioned high pressure crater zone in the furnace has a considerable effect on the metal tapping and the gas flow rate from the tap hole. The predicted tapping rate compares well to...

The Norwegian ferroalloy industry has high ambitions regarding environmental standards. Basic research work has been performed to improve the fundamental understanding of ferroalloy processes and the environ- mental aspects. This paper will present work dealing with the understanding of formation and control of NOx, PAH and dioxins. During this work various techniques and methods have been applied, such as comprehen- sive industrial measurements, laboratory experiments, model development and application of Computational Fluid Dynamics (CFD). The main goal has been to reduce the environmental impact of ferroalloy plants, by means of improving the combustion processes done by introducing new charging routines and optimized fur- nace operations, instead of installing expensive gas treatment systems. The Norwegian obligations in accordance with the Gothenburg protocol are to reduce the NOx emissions by 30%, compared with the 1990 level within 2010. Measures developed in this work have r...

Based on requirements of circular economy and environmental protection for metallurgical slag reutilization, the research of hot metal dephosphorization with steel slag from converter is carried out in this paper. The effect of converter slag with different addition of CaO, Fe2O3 for the dephosphorizing rate is studied though analyzing the main phases of converter slag with SEM. The result indicates the main phases of converter slag are Ca2SiO4, RO phase, calcium ferrite and their combinations. The dephosphorizing rate is 29.41% while the converter slag mixes no CaO or Fe2O3, and the dephosphorizing rate rises as the increase of CaO and Fe2O3, then the dephosphorizing rate reaches 98.21% when the content of converter slag is 28%.

Исследование рассматривает процесс растворения осадков карбонатов и фосфатов редкоземельных металлов при изменении концентрационных параметров системы. Задачей исследования является определение характера процесса растворения при различных составах изучаемых сред. В результате анализа теоретической базы представлены качественное и количественное содержание редкоземельных металлов в красном шламе и фосфогипсе, обуславливающие интерес к рассматриваемой проблеме. Также были рассмотрены доступные технологии извлечения редкоземельных металлов из красного шлама и фосфогипса, приведены их преимущества и недостатки. Рассматривался перспективный карбонатно-щелочной способ извлечения редкоземельных металлов. Для выявления возможности проведения процесса были рассчитаны термодинамические параметры системы. В ходе эксперимента рассмотрены факторы, влияющие на процесс растворения: концентрация карбонат-иона, природа катиона растворителя и катиона редкоземельного металла. В качестве анализируемых компонентов рассматривались карбонаты и фосфаты европия, гольмия и неодима. Карбонаты и фосфаты неодима, европия и гольмия растворялись в модельных растворах карбоната K 2 CO 3 с концентрацией от 0,2-4,5 моль/л до состояния равновесия. Полученные результаты показывают зависимость растворимости осадков редкоземельных металлов от природы растворителя и его концентрации. Данные представлены в виде изотерм растворимости. На основании экспериментальных данных рассчитаны значения степени извлечения редкоземельного металла в раствор. Для карбонатов неодима, европия и гольмия максимальная степень извлечения α max составила соответственно 72,8 %, 81,2 %, 83,0 % масс. В ходе эксперимента с растворением фосфатов лантаноидов получены следующие результаты: максимальная степень извлечения неодима -60,59 %, европия -51,66 %, гольмия -93,01 %. Ключевые слова: карбонат калия, изотерма, растворение, редкоземельные металлы, техногенное сырье, лантаноиды, шлам.

There are many medium sized above-ground steel storage tanks in all industrial plants and under construction projects in Iran. Generally, most of these site-fabricated steel storage tanks are erected via conventional methods, which requires heavy capacity mobile cranes to lift, fit-up, and weld shell courses. In addition, another erection method, i.e. jack lifting erection method is globally well implemented in the past two decades, which may bear in many advantages over the conventional erection method. In this paper, the most significant advantages of this method for implementation in Sungun Copper Concentrator Plant (Phase III) is discussed briefly.

Nb O , visando a produção posterior de compósitos híbridos constituídos por polipropileno, pentóxido de nióbio e fosfato de cálcio em concentrações ideais, além de um nanomaterial com características antimicrobianas, como uma melhor alternativa econômica para enxertos ósseos aplicados à área odontológica. A escolha para os materiais base dos compósitos em estudo ocorreu, principalmente, devido a características específicas de cada um desses componentes, como a inerência biológica, a biocompatibilidade, a abundância no país e a bioatividade. Para a realização deste trabalho, foram confeccionados corpos de prova (CPs) com diferentes concentrações de Nb O (3.75%, 7.5%, 11.25% e 15%) em uma matriz de PP. Com o intuito de avaliar as características mecânicas, físicas e morfológicas, todos os CPs foram analisados através de ensaios mecânicos convencionais (tração, flexão e impacto) e da microscopia eletrônica de varredura (MEV).

Aim: This study investigates the dissolution of tantalite mineral from granitic pegmatite in Okpella,
Northern Edo State, Nigeria.
Study Design: Elemental and mineral composition analysis of tantalite ore sample from Okpella
was carried out using X-ray fluorescence and X-ray diffraction. Response Surface Methodology(RSM) and the shrinking core model were used in designing the study while the effects of
temperature, stirring speed, particle diameter, and mixed acids concentrations were investigated in
the dissolution rates of the mineral.
Duration of Study: 50 experimental runs were designed using RSM Central Composite Design
(CCD) to optimize variables including HF concentration (1-8 M), H2SO4 concentration (0.5-3 M),
temperature (32-82°C), stirring speed (0-500 rpm), and particle size (0.1-0.3 mm), with a constant
contact time of 240 minutes.
Methodology: Pulverized tantalite samples (0.1-0.3 mm) were reacted with varying concentrations
of hydrofluoric and sulphuric acids (1-8 M and 0.5-3.0 M, respectively) for 240 minutes, with stirring
speeds between 0-500 rpm and temperatures from 32 to 82°C. The mixture was stirred in a water
bath with 50 ml of mixed acids solution and 2 g of ore. After the reaction, the solution was
decanted, and the residual ore was washed, dried at 60 °C, and weighed. The difference between
the initial and final weights indicated the amount of undissolved tantalite ore.
Results: Ore characterization results revealed high concentration of tantalum (34.17%), iron
(12.55%), niobium (8.38%), and titanium (6.01%), with other elements present in smaller amounts.
Optimal conditions were found to be 8 M HF, 0.5 M H2SO4, 82°C, 500 rpm stirring speed, and 0.1
mm particle size, resulting in 97.28% dissolution of tantalite ore. Regression analysis demonstrated
model robustness with an F-value of 16.70 and a P-value of 0.0001, indicating HF concentration
and stirring speed as the most impactful factors. The model’s R² value of 0.9201 and adjusted R² of
0.8650 confirm its predictive accuracy. Analysis using the shrinking sphere model showed that film
diffusion control is the primary limiting step with t/τ=0.999, while reaction control resulted in slightly
lower conversion with t/τ=0.973, highlighting film diffusion as the main constraint but with high
conversion efficiency.
Conclusion: The findings from this investigation not only reveal the dissolution of tantalite ore
through a detailed experimental approach, identifying optimal conditions -8 M HF, 0.5 M H2SO4, 82
oC, 500 rpm stirring speed and 0.1 mm particle size- that achieve a 97.28% dissolution, but they
also enhance our understanding of mineral processing. These understanding are crucial for mineral
dissolution up scaling technologies in industrial applications, which will potentially leads to a more
efficient extraction method that could significantly reduce costs and environmental impacts in the
mining sector. This research could drive advancements in sustainable resource recovery and
contribute to sourcing of critical minerals.

This study presents a comparative investigation of the tribological behaviour and microstructural characteristics of two different alloys, namely 77.3 % Al-1.8 % Fe-16.7 % Si and 54.1 % Al-12.8 % Fe-27.8 % Cr. High temperature alloys are fabricated by stir casting technique. Tribology analysis is conducted to assess wear, crack formation, and cavity zones for both alloys using Scanning Electron Microscopy (SEM). Additionally, optical micrography is employed to examine their microstructures. The results reveal significant differences between the two alloys, with the 77.3 % Al-1.8 % Fe-16.7 % Si alloy exhibiting higher Vickers hardness and superior wear resistance compared to the 54.1 % Al-12.8 % Fe-27.8 % Cr alloy. Optical micrographs confirm a well-defined grain distribution for the former alloy and a similar homogeneous microstructure for the latter. Ključne reči • nauka o materijalima • vrtložno livenje • proizvodnja legura • tribološka analiza • površinsko oštećenje Rezime U ovom radu je predstavljeno uporedno istraživanje tribološkog ponašanja i mikrostrukturnih karakteristika dve razli

This paper investigates the metallurgical factors that contributed to the failure of several cast U-clamps made of HK40 steel U-clamps during the installation of a pre-startup heater in a petrochemical plant. The presence of extensive macro/micro-shrinkage porosity is identified as the root cause of the failure. The severe shrinkage-related porosity in the material, confirmed by metallographic examination and non-destructive X-ray radiography testing and evidenced by a severe loss in tensile ductility, resulted in a unique fully dendritic fracture surface characteristic. It was found that the loss of structural integrity associated with macro-shrinkage voids and loss of toughness associated with microporosity led to premature failure of Uclamps when subjected to bending forces during installation. The casting process should be designed to guarantee a higher Niyama criterion value, defined as the local thermal gradient divided by the square root of the local cooling rate, in the casting to produce a sound U-clamp.

It have been experimentally studied the temperature dependences of the effective Hall coefficient of amorphous alloys Fe73Cr12B15 and Fe75Cr10B15 based on 3d elements, obtained from the liquid state by ultra-fast cooling, using the Van der Pauw method in the temperature range of 300-773K are experimentally studied. The temperature dependence of the electrical resistivity of the samples was studied using the four-probe method in the temperature range 300-773K. The temperature dependence of the specific magnetization of the samples has been studied experimentally using a vibration magnetometer at temperatures of 300-1100K at sample heating rates of 10, 20 and 40 K/min. It is found that the ferromagnetism-paramagnetism phase transition temperatures of the samples have a complete correlation with the results of the Hall coefficient, resistivity and specific magnetization, and the amorphous-crystalline phase transition temperatures vary depending on the heating rate. The results of the mutual and temperature dependence of the electrical, magnetic and galvanomagnetic properties of the samples are analyzed.

Over the last decade, the first principle study, has achieved a great importance in the field of quantum chemistry, solid state physics and material science. This study is about to investigate the different prosperities of many-body electronic systems and it is a quantum mechanical simulation approach. Eventually, this approach has a tool to predict some new materials and their properties computationally. This method can save the use of chemical methods, which can be harmful to the environment. In this review article, the research field of first principle techniques has been explored for some important semiconductor materials.

By the decision of the Presidium of the Higher Attestation Commission under the Ministry of Higher Education, Science and Innovation of the Republic of Uzbekistan dated October 30, 2023, the journal was included in the list of scientific publications of the UAC.

Mаqolаdа tikuv mаshinаlаrining moki vа nауchаsining hаrorаt kuchlаnishini vа deformаsiуаsini bаholаshning mаtemаtik modeli ishlаb chiqilgаn, buning uchun moki ichi g'ovаk silindr sifаtidа qаrаlаdi, qаtlаmlаrdаgi hаrorаtning kesishishi vа elаstik moduli, hаrorаtdаn kengауish koeffisiуentlаri nаzаriу jihаtdаn o'rgаnilаdi, moki silindrining уon уuzаlаridа o'q уo'nаlishidаgi vа tаngensiаl kuchlаnishlаrni hisoblаsh uchun kerаkli formulа berilgаn. Olingаn mаtemаtik ifodа nаtijаlаri mokining butun tаnаsi bo'уlаb уemirilishi vа tаrqаlishini vа moki vа g'аltаkning уon chekkаlаri bo'уlаb mo'rt kristаllаrаro уemirilishni аniqlаsh imkonini berаdi. Bundаn tаshqаri, normаl kuchlаnishgа perpendikulуаr bir nechtа tekisliklаr bo'уlаb tаrqаlаdigаn to'lqinli strukturаning уаltiroq kristаlli dаrzlаrigа xos bo'lgаn mo'rt sinish vа tаngensiаl kuchlаnishlаr tufауli plаstik deformаsiуаlаr pауtidа уuzаgа kelаdigаn siljish shаklidаgi egiluvchаn sinish tаhlil qilindi.

Single-pass and mu lti-pass deformation schedules have been applied to low-C microalloyed steel containing Nb, Ti and V. Heavy deformat ion (∼80%) in a single pass, just above or below the austenite-to-ferrite transformat ion temperature (A r3 ), followed by slow-cooling (@1°C/s) of the samp les to room temperature, resulted in the formation of ult ra-fine ferrite grain structures with average grain size of ~2 to 3 µm. Ferrite grain size variat ion observed in the ultra-fine grained steel can be explained in view of several metallurg ical phenomena such as, static and dynamic strain-induced austenite (γ) → ferrite (α) transformation, dynamic recovery, dynamic recrystallisation, and grain-growth of ferrite. Multi-pass deformat ion schedule can also refine the ferrite-grain size close to the ultra-fine range (∼3 µm) provided more than 50% reduction is applied in the fin ishing stage, between A e3 and A r3 temperatures.

The Book of Mormon contains many words left untranslated by Joseph Smith, such as cureloms, cumoms, senine, and ziff. While some might wonder why these words are left untranslated, a closer examination of the kinds of words that are simply transliterated as well as the frequency at which these phenomena occur provide evidence that Joseph Smith actually had an ancient record that he was translating into English. In this paper, I examine why some words have been transliterated in historical translations of the Bible or other ancient texts and compare these explanations to the Book of Mormon. In the end, I show that the Book of Mormon consistently transliterates the same types of words typically left untranslated in other works in ways that would have been unknown to Joseph Smith.

J. Hampl, B. Smetana, VŠB-TU Ostrava, Faculty of Metallurgy and Materials Engineering, Czech Republic J. Odehnal, PILSEN STEEL, s.r.o., Pilsen, Czech Republic The paper analyzes the technological parameters, micro-purity and mechanical properties of castings of steel alloyed with calcium. The effect of calcium on the steel was analyzed on samples taken in the process of casting heavy castings and ingots of the weight of ranging from 40 000 to 60 000 kg. Samples for the determination of the liquidus temperature and the solidus temperature of cast steels were analysed using differential thermal analysis (DTA). The production of low alloyed steel grades was performed on the EAF ASEA-SKF facilities and the production of highalloyed steels on the EAF ASEA-SKF SS-VOD facilities. The purity calcium was added into the steel by the injection of a stuffed profile.

In many manufacturing process which are based on melting and solidification, like casting, measurement of viscosity and prediction of fluidity of molten metal in variant temperatures and alloy composition could improve quality of process and decreasing losses. In this paper different methods for measurement of viscosity like capillary method, oscillating vessel viscometer, falling body or counterbalanced sphere viscometer, oscillating plate method, rotating cylinder and … have been investigated. Arrhenius equation, Andrade treatment, Hildebrand's free volume theory, Chhabra model and … are the models which were used for estimation of viscosity of metals and alloys and their relation with temperature. Finally comparison of different procedure for viscosity measurement of molten metals is presented.

The effect of cooling methods after heat treatment on the microstructure and mechanical properties of reinforced low alloy steel were studied. The microstructure characteristics were observed under OM(optical microscope), SEM(Scanning Electron Microscope). Charpy V Notch impact tests at different temperatures (-30°C, -10°C, +30°C) along with Tensile tests were performed and the mechanical properties were evaluated. The evaluated results indicated that cooling with water led to a mix of ferritic matrix and tempered martensite, whereas when air cooled the microstructure was a mix of matrix of ferrite and tempered bainite. This is basically due to the intensity of cooling rate in both the cooling techniques. In air cooling the combination of strength and toughness was better than in comparison with water cooling.

Международный центр научного сотрудничества «Наука и просвещение» СОВРЕМЕННЫЕ СТУДЕНЧЕСКИЕ ИССЛЕДОВАНИЯ сборник статей Международной научно-практической конференции, Состоявшейся 15 августа 2024 г. в г. Пенза Пенза МЦНС «НАУКА и просвещение» 2024 2 СОВРЕМЕННЫЕ СТУДЕНЧЕСКИЕ ИССЛЕДОВАНИЯ VII международная научно-практическая конференция | МЦНС «НАУКА И ПРОСВЕЩЕНИЕ» УДК 001.1 ББК 60 C56 Ответственный редактор: Гуляев Герман Юрьевич, кандидат экономических наук C56 СОВРЕМЕННЫЕ СТУДЕНЧЕСКИЕ ИССЛЕДОВАНИЯ: сборник статей Международной научно-практической конференции.-Пенза: МЦНС «Наука и Просвещение».-2024.-160 с.

Настоящий сборник составлен по материалам IX Международной научно-практической конференции «НАУЧНЫЙ ФОРУМ», состоявшейся 15 августа 2024 г. в г. Пенза. В сборнике научных трудов рассматриваются современные проблемы науки и практики применения результатов научных исследований. Сборник предназначен для научных работников, преподавателей, аспирантов, магистрантов, студентов с целью использования в научной работе и учебной деятельности. Ответственность за аутентичность и точность цитат, имен, названий и иных сведений, а также за соблюдение законодательства об интеллектуальной собственности несут авторы публикуемых материалов. Полные тексты статей в открытом доступе размещены в Научной электронной библиотеке Elibrary.ru в соответствии с Договором №1096-04/2016K от 26.04.2016 г.

Presentation overview of PLASTER MOLD CASTING with process,application, advantage, and disadvantage.
This presentation was performed by Anik Talukder (199023), and myself Shariful Islam (199024) in January 2023. Department of Materials and Metallurgical Engineering at Dhaka University of Engineering and Technology, Gazipur.

Bu çalışmada, paslanmaz çelik ve bakır levhaların farklı oranlarda patlayıcı miktarları kullanılarak patlamalı kaynak yöntemi ile kaynaklanabilirliği ve patlayıcı oranının ara yüzey özelliklerine etkisi araştırılmıştır. Deneysel çalışmalar sonunda, patlama kaynağıyla paslanmaz çelik ve bakır malzemelerin birleştirilebildiği ve üst parça ağırlığına göre patlayıcı oranı arttığında ara yüzeyin, doğrusal bir birleşme ara yüzeyinden dalgalı bir hale dönüştüğü görülmüştür. Patlayıcı oranının artışıyla beraber oluşan dalgaların, boylarında ve genliklerinde bir artış olduğu, ayrıca çarpışmadan kaynaklanan soğuk deformasyondan dolayı, ara yüzeye yakın bölgelerin ve levhaların dış yüzeylerinin sertliklerinde bir artışın meydana geldiği tespit edilmiştir.

Dunyo bo'ylab 2021 – yilda 1.5 mlrd donaga yaqin smartfonlar sotilishi aytilmoqda. Elektromobil ishlab chiqarish 2025 yilga kelib esa 12 mln donani tashkil qilishi kutilmoqda. Roskill (muhim ahamiyatga ega bo'lgan materiallarni tahlil qiluvchi kompaniya) – 2020 yilda dunyo bo'yicha rafinirlangan kobalt metalini ishlab chiqarish 130 ming tonnani tashkil etgan bo'lsa unga bo'lgan talab 136 ming tonnani tashkil qildi. O'rtadagi kamomad 6 ming tonnani tashkil etdi. Bu kamomadni bartaraf etish uchun esa kobalt saqlagan yangidan yangi xomashyo resurslarini izlab toppish va uni qayta ishlashni talab etmoqda.

Owing to the inevitable mu ltiaxial state of deformation kinematics and stresses in bulk metal forming processes, evaluation of workability calls for materials testing using combined axial and torsion tests. A high temperature comb ined axial and torsion testing system (ATTS) was developed in IGCAR for assessing workability of various materials under mu lti-axial state of stress and deformation conditions up to 1300 °C. In this paper, results from fin ite element modeling of axial torsion tests and seamless tube ext rusion are presented. Co mbined torsion-co mpression tests would represent the state of stress and extent of deformation in tube extrusion more closely than axial torsion with tension or pure torsion tests.

Mandibula kırıklarında miniplak kullanımı yaygın görülen müdahale yöntemlerinden biridir. Mandibula kemiği kırıklarında plak-fiksatör uygulaması öncesi tetkiklerde kullanılacak biyomalzemenin taşıyabileceği sınır değerlerinin ortaya konması gerekir. Plak ve fiksatörün, çenenin maksimum kuvvete ulaştığı durumlar dahil her türlü etkiye karşılık verir nitelikte olması istenmektedir. Cerrahi müdahale öncesinde kullanılacak malzeme ve plak geometrisinin belirlenmesi tüm bu etkenler nedeniyle istenilen cerrahi uygulamaya ulaşmak için gereklidir. Bu çalışmada, yaygın olarak kullanılan Titanyum Alaşım ile tasarlanmış ve "I" geometriye sahip plakların tespit konumları kıyaslanmıştır. Her bir model ve modele ait malzeme için ANSYS® sonlu elemanlar yazılımı ile gerilme ve deformasyon kapasiteleri karşılaştırılmıştır. In vitro çalışmaları kadar kullanılabilir değerler elde edilebilen sonlu elemanlar analizi sonuçları I tipi mandibula plakları ve malzemeleri için değerlendirilmiştir. İki farklı tip mandibula kırıklarında kullanılan I tipi plakların hangi şartlar altında tespit tercihinin uygun olduğu ifade edilmiştir.

It is well known for a long time that the classical solders based on lead and tin represent a serious health risk and environmental problem. Hence there is a strong drive to find lead-free alternatives. Lead-free solders presently used have often reliability problems, usually caused by worse mechanical properties, higher tendency to oxidation, higher occurrence of undesirable intermetallic phases and higher melting temperature. The effect of lowering melting point of silver powder was studied in this work, as a potential model solution for low-toxic solders. The experimental results demonstrate that for powdered Ag the annealing temperature of 400, 300 and even 200 °C is sufficient to produce a continuous Ag layer and form a firm junction between copper plates. A transition oxide layer is observed in some cases at the Cu-Ag interface, the thickness of which increases with annealing time, hence the resulting structure can be described as CuCu-OAg. Microstructure, composition profiles and local mechanical properties were studied on cross-sectional samples by analytical electron microscopy and depth-sensing indentation technique.

Dyslexia is a specific reading disorder associated with difficulties in word recognition, text decoding, and memory retention of what has been read. One of the key causes of dyslexia is a visual deficit, which includes problems with visual perception and information processing. Neurocorrection methods represent a promising approach to solving this problem. The article discusses modern neurocorrection methods aimed at overcoming the visual deficit in children with dyslexia and provides examples of the successful application of these methods.

Introduction: Mine tailings are toxic wastes that generate environmental risks when exposed to water and oxygen. This study evaluates the use of gold tailings to recover gold and produce bricks, applying a circular economy approach. Methodology: The sample was characterized to determine the mineral species and properties. Flotation tests were then performed on the tailings. Results: Characterization of the Marañon tailings revealed high concentrations of gold in arsenopyrite, with 90% of the gold and silver in particles smaller than 74 μm. Arsenopyrite at this fine size can damage the environment due to its toxicity. Discussion: The method offers an advantage in reducing the volume of tailings by making bricks, in addition to ornamental products made with cement and sodium silicate at room temperature. Conclusions: Circular economy applied to tailings management in mining has shown environmental and economic benefits. Waste generation is reduced and valuable materials such as gold and silver are recovered. In addition, treated tailings can be reused in the manufacture of bricks without causing environmental impacts. Keywords: Mining tailings; flotation; arsenopyrite; gold; pyrite; circular economy; characterization; bricks.

This paper reports on the investigation of metallurgical and microhardness properties of laser metal deposition of Titanium alloy- Ti-6Al-4V. Ti-6Al-4V substrate and Ti-6Al-4V powder (150-200 µm) both at 99.6% purity were used in this study. The input laser power varied between 0.8 and 4.0 kW while other processing parameters were kept constant. They include the scanning speed of 0.005 m/sec, powder flow of 1.44 g/min and the gas flow rate of 4 l /min. The microstructure and the microhardness were examined under the optical and scanning electron microscope. The microhardness was measured using the Vickers hardness tester. The study revealed that the layer band occurred in all the samples except those samples at very high laser powers. The microstructure of the heat affected zone is characterized with fine globular primary alpha and beta grains at low laser power and become coarse as the laser power was increased. The microhardness was found to initially increase and then decrease as...

Существующая в настоящее время методическая система изучения физики не соответствует современному состоянию физической науки и, таким образом, не способствует формированию современного стиля мышления, которым должен обладать гармонично развитый, активно действующий спе ци алист-профессионал. В статье приводится анализ феномена современного стиля мышления и обсуждаются принципы, которые должны лечь в основу создания методической системы изучения постнеклассической (современной) физики.

Pabrik Silika yang berkapasitas 15.180 tontahun didirikan di Indramayu Jawa Barat untuk memenuhi kebutuhan di dalam dan luar negeri. Pabrik ini menggunakan bahan baku abu sekam padi kandungan silika 934 dengan proses presipitasi Aldcroft dan tekhnologi Kalapathy. Manfaat dari silika antara lain digunakan untuk bahan industri kaca keramik kosmetik serta bahan campuran pasta gigi. Proses produksi silika secara umum dibagi dalam tiga tahap. Tahap pertama adalah Ekstraksi abu sekam padi dengan solvent NaOH 2N di dalam leaching tank. Tahap kedua yaitu tahap reaksi antara natrium silikat encer 16 asam sulfat encer 38 dan NaCl 363 di dalam reaktor yang menghasilkan slurry. Selanjutnya slurry difiltrasi untuk memisahan partikel silika dari liquid yang dilakukan di dalam rotary drum vacum filter. Tahap ketiga adalah tahap pengeringan di dalam spray dryer. Selanjutnya tahap pengecilan dan homogenisasi menggunakan ball mill dan diteruskan menuju vibrating screen untuk mendapatkan ukuran silika...

Plastik enjeksiyon kalipciligi, plastik urunlerin hassas ve seri bir bicimde basilmasini saglayan en onemli uretim yontemlerinden biridir. Mekanik ozellikler, plastik urunlerin kalitesine onemli olcude etki eder. Otomotiv sektorunde guvenlik ve konfor alaninda odun vermeden yuksek dayanimli alasimlarin kullanimi ve dusuk yakit tuketimi onemli bir hedef haline gelmektedir. Aluminyum alasimlari arac hafifletme ve carpisma guvenligi gibi konularda daha iyi sekillendirilebilirlik ve yuksek mukavemet hedefleri icin surekli gelistirilmektedir. Otomotiv sektorunde sac, ektruzyon ve dokum formundaki aluminyum kullanimi arac hafifletme calismalarinda onemli derecede avantaj saglarken, arac pasif guvenlik sistemlerinin tasariminda da etkili sonuclar vermektedir. Bu calismada, farkli geometrilere sahip aluminyum ekstruzyon ezilme kutularinin carpisma performansina isil islem parametrelerinin etkileri incelenmistir. Isil islemler 160 °C’de ve farkli bekleme surelerinde gerceklestirilmistir. Far...

Splat cooled uranium has been used in a range of studies for around 50 years, coming into focus more recently as a source of ‘glassy’ or ‘amorphous’ uranium for super-conductor and electromagnetic experiments. But apart from a very cursory optical metallographic study in the early 60’s[1,2], no physical characterisation work has ever been done. The range of new techniques which have been developed since the initial study have significantly broadened the possible approaches, and have led to a truly novel study. Perhaps the most significant finding of the study has been the demonstration that using a splat cooling method with cooling rates of the order of 106 K/s it has been possible to preserve the high temperature (existing for T > 775o C) γ-phase at room temperature (RT) in pure uranium, something which was hither-to considered impossible. The γ-phase observed using EBSD were both intra-granular micro-grains (typically siting along sub-boundaries) and inter-granular micro-grains...

Международная научно-практическая конференция "ФИЗИКА ПОЛУПРОВОДНИКОВ, ФУНДАМЕНТАЛЬНЫЕ И ПРАКТИЧЕСКИЕ ПРОБЛЕМЫ СОВРЕМЕННОЙ ЭЛЕКТРОНИКИ И ЭНЕРГЕТИКИ" Посвящается 75-летию доктора физико-математических наук, профессора Г. Гуломова Xalqaro ilmiy-amaliy konferensiya "YARIMO'TKAZGICHLAR FIZIKASI, ZAMONAVIY ELEKTRONIKA VA ENERGETIKANI FUNDAMENTAL VA AMALIY MUAMMOLARI" fizika-matematika fanlari doktori, professor G'.G'ulomovning 75 yilligiga bag'ishlangan I 18-19 sentabr, 2024-yil Namangan

Gravity concentration adalah metode pemisahan mineral berdasarkan perbedaan densitas antara mineral berharga dan pengotor. Praktikum ini bertujuan mempelajari proses gravity concentration menggunakan shaking table, yang memanfaatkan aliran horizontal untuk memisahkan mineral berat dari material pengotor. Pasir besi yang mengandung magnetit (Fe₃O₄) digunakan sebagai sampel. Hasil pengamatan menunjukkan bahwa shaking table berhasil memisahkan konsentrat mineral berat dengan baik, di mana parameter percobaan seperti selisih minim dari material balance, metallurgical balance, persentase recovery yang mencapai 99%, dan ratio of concentration yang tidak jauh dari nilai 1. Shaking table efektif dalam meningkatkan konsentrasi mineral berat, dengan efisiensi pemisahan yang bergantung pada pengaturan kemiringan dek dan persen solid dalam slurry. Metode ini cocok untuk digunakan dalam industri metalurgi untuk pengolahan berbagai jenis mineral, terkhususnya magnetit.

Crushing dan grinding dalam pengolahan mineral, merupakan dua tahapan utama dalam kominusi bijih untuk meningkatkan derajat liberasi mineral. Metode yang digunakan meliputi penggunaan jaw crusher untuk proses crushing dan rod mill untuk grinding, dengan variasi waktu penggerusan yang 5-12 menit. Hasil dari praktikum menunjukkan bahwa ukuran produk setelah proses primary crushing tetap sama pada 5.3 cm, sedangkan secondary crushing berhasil mengurangi ukuran hingga 2,1 cm. Proses grinding dengan variasi waktu menunjukkan peningkatan fraksi lolos pada ayakan 65 Mesh, dimana waktu grinding yang lebih lama menghasilkan ukuran partikel yang lebih halus. Penting untuk melakukan pengendalian ukuran partikel dan pemilihan metode peremukan serta penggerusan yang tepat untuk mencapai hasil optimal dalam liberasi mineral berharga dari ikatnnya, yang mana akan bedampak langsung terhadap proses konsentrasi.

Sampling sebagai tahapan pertama dalam pengolahan mineral bertujuan untuk mengambil sebagian kecil dari material yang lebih besar agar dapat mewakili keseluruhan karakteristik deposit. Tahapan ini tentu dilakukan dengan hati-hati agar sampel yang diambil homogen dan representatif, sehingga hasil analisis dapat diandalkan untuk menentukan langkah-langkah pengolahan selanjutnya. Praktikum ini bertujuan untuk memahami metode sampling yang tepat dalam pengolahan mineral, khususnya pada pasir besi, pengolahan datanya dan pemahaman derajat liberasnya. Metode sampling secara manual yakni cone and quartering, yang mengurangi ukuran sampel dengan membaginya menjadi 4 bagian sama rata, untuk kemudian dipilih 2 bagian agar memastikan representativitas sampel. Sampel pasir besi berukuran 65 dan 100 mesh dianalisis menggunakan mikroskop untuk mengidentifikasi mineral yang terkandung, seperti Fe₃O₄ dan SiO₂. Hasil pengamatan menunjukkan derajat liberasi Fe₃O₄ sebesar 50% dan 77,27%. Metode cone and quartering efektif untuk pengambilan sampel kecil, namun untuk skala yang lebih besar, diperlukan alat yang lebih presisi untuk meningkatkan akurasi hasil.