Composition Of Cast Iron Research Articles

Характеристики низьколегованого чавуну для формокомплектів у склотарній галузі

The growth of national production of glass packaging products requires the use of new materials and technologies to create conversion conditions for the production of moulds and their introduction into production to replace similar imported products. The main problem faced by glass packaging manufacturers when operating moulding systems is their low service life and failure due to cyclic exposure to high temperatures. The operating environment of a moulding set is caused by the aggressive action of glass material with high adhesive properties, which, in long-term contact, causes defects on the surface of the moulds in the form of oxidised areas and cracks The high moulding speed and temperature of the aggressive working environment prompts the correction of mould properties, specifically the selection of a chemical composition of a material with a low content of alloying elements, which will improve the performance characteristics of moulds and economic indicators of production. The paper presents the preparation of the chemical composition of low-alloy cast iron, determines its critical points of phase transformation, establishes its heat resistance characteristics, and recommends it for use as a moulding material. The results of the differential thermal analysis show that the onset of phase transformations in the experimental cast iron is 17.7 °C higher than the critical point of the sample from the disused mould. The change in the specific mass of the samples after 50 hours of scale resistance tests was determined, which is at a high level and amounts to 0.164 g/(cm2·h). It has been identified that the growth resistance of cast iron has linear dependencies with increasing influence of cycles, which indicates the absence of sharp phase transformations and, as a result, the absence of dynamic changes in the material during operation. It was identified that the destruction of the experimental cast iron samples occurs at the 60th cycle of high test conditions, which demonstrates positive crack resistance and the presence of a stable structure of the experimental cast iron.

Study of the Influence of Modification and Heat Treatment of Cast Iron Grinding Balls on Their Operational Properties

The study addresses the enhancement of wear resistance and impact strength of cast iron grinding balls used under intensive abrasive wear and impact conditions at ore processing plants. The primary aim is to improve the operating properties of cast iron by optimizing its chemical composition and introducing advanced thermal and chemical-thermal treatment methods, including controlled cooling. To achieve this goal, two alloyed cast iron compositions with added chromium, molybdenum, and nickel were used, and the base composition was further modified with titanium and titanium carbonitride to increase the microhardness of the matrix phases. Experimental samples underwent various heat treatment regimes, including quenching and normalization, to evaluate the effect of these processes on the microstructure, hardness, and impact resistance of the grinding balls. Microstructural analysis revealed that additional alloying elements and modifiers contributed positively to forming a more homogeneous and fine-grained structure with an increased proportion of carbide phases. The key findings indicated that the optimized structure of the cast iron grinding balls achieved 10 units higher hardness and 2-4 units greater impact resistance than the base composition after heat treatment. Furthermore, titanium and titanium carbonitride modifications enhanced the performance characteristics of the balls by several additional units. Thus, the developed treatment regimes and modified cast iron composition significantly increase the wear resistance of grinding balls, contributing to reduced grinding costs in industrial applications.

Structural-phase state and properties of heat and wear resistant cast irons of Cr–Mn–Ni–Ti system additionally alloyed with Al and Nb

The paper presents the data on phase composition and structure forming for the alloys, on distribution of elements among the alloy structural components, on variation of wear resistance, scale resistance, growing stability and mechanical properties of cast iron of Cr–Mn–Ni–Ti–Al–Nb system depending on different aluminium and niobium content and thermal ac-cumulating capacity of a casting mould. Complex carbides (Nb, Ti)C are forming in white cast iron during niobium alloying. Quantitative metallographic analysis of (Nb, Ti)C carbides and (Cr, Fe, Mn)7C3 complex carbides was carried out on the samples with examined composition. Aluminium provides favourable influence on forming of the thin protective spinel-type films with minimal amount of defects; diffusion through such oxide film is very difficult. Joint alloying by aluminium and niobium leads to simultaneous increase of heat resistance and wear resistance. Wear resistance increased as a result of enlargement of the part of primary carbides (Nb, Ti)C with high hardness in the structure of cast iron. Composition of oxide films includes aluminium, which strengthens their protective properties and rises of the alloy scale resistance. It is found for the first time that niobium doping leads to secondary solidification during cooling in the casting mold. Dispersion particles of М7С3 carbides are forming in solid state, thereby no structure degradation occurs during testing at increased temperatures, and growing stability rises. On the basis of the complex of the conducted researches the rational composition of heat and wear resistant cast iron is offered at the following ratio of components, wt. %: 2.1–2.2 C; 4.5–5.0 Mn; 18.0–19.0 Cr; 1.0–1.2 Ni; 0.4–0.6 Ti, 2.0 Nb; 2.0 Al. Wear resistance increased 1.2 times compared to cast irons before the introduction of aluminum and niobium, and scale resistance – 2.4–4.5 times depending on the type of casting mold, the index of growth resistance is equal to zero for cast irons cast in dry SLM

Design and Control of the Natural Frequency of Brake Discs in the Aspect of the Gray Cast Iron Production Process.

The results of research on the influence of the chemical composition of cast iron and its potential changes in the production cycle on the elastic properties and the correctness of numerical simulations of the natural frequency of ventilated brake discs are presented. The tests were carried out for three grades of gray cast iron with flake graphite with a eutectic saturation coefficient ranging from 0.88 to 1.01. A quantitative metallographic assessment of the pearlitic cast iron matrix and graphite precipitates was carried out, and the hardness and compressive/tensile strength of individual cast iron grades were determined, taking into account the limit contents of the alloying elements. Next, ultrasonic tests were performed, and the elastic properties of cast iron were determined. Based on the obtained data, a numerical modal analysis of brake discs was performed, the results of which were compared with the actual values of an FRF frequency analysis. The error of the computer simulations was estimated at approx. 1%, and it was found that the accuracy of the calculations of the first natural frequency did not depend on the dimensions (size) of the discs and the chemical composition of the cast iron from which they were cast. The functional relationships between the chemical composition of cast iron, its strength and elasticity and the first natural frequency of the disc vibrations were determined, and a database of the material parameters of the produced cast iron grades was developed. An implementation example showed the validation of the brake disc design with natural frequency prediction and demonstrated a high convergence of the experimental results with the simulated values. Using I-MR control cards, both the effectiveness of designing and predicting the natural vibrations of brake discs based on the implemented material database as well as the stability of the gray cast iron production and disc casting processes were confirmed.

ОЦІНКА НАПРУЖЕНОГО СТАНУ РОБОЧОГО ШАРУ ВАЛКІВ КОЕРЦИТИМЕТРИЧНИМ ЕКСПРЕС-МЕТОДОМ

The purpose of the work is the problem of researching the influence of chemical composition and structure on the indicators of operational stability of centrifugal two-layer rolling rolls made of high chromium cast iron by the coercimetric express method. In order to ensure the achievement of this goal, the following tasks were set and solved: conducting an analysis of the causes of the destruction of the surface layer of rolls; building a mathematical model for studying the influence of the chemical composition and structure of cast iron on the level of hardness and coercive force; using the coercimetric method to analyze the quality of rolled rolls. Conclusions. Forecasting the behavior of the rolls during operation is inextricably linked to the analysis of the main factors on which the level of properties and operational stability of the working layer depend. The properties of high-chromium alloys are closely related to the type of phases formed and their ratio. The amount of residual austenite and martensite in the structure of the alloy has the greatest influence on the properties of the alloy (in the studied interval of changes in the proportion of phases). The operational layer of two-layer high-chromium rolls is characterized by a high level of residual stresses. Exceeding the permissible level of stresses or their unfavorable distribution can cause premature destruction during the operation of the roll. With the help of the coercimetric express method, it is possible to solve a fairly wide range of tasks of quality control of rolls, related to the determination of the level and distribution of residual stresses in the working layer of the rolls. This is because the intensity of the process of formation of thermal cracks under conditions of thermo-cyclic loading largely depends on the level of residual compressive stresses. Too high a level of stresses or their unfavorable distribution can cause premature destruction of the working layer of the roll, because the typical type of destruction due to an unbalanced distribution of stresses is cracking. A local increase in the level of coercive force can be the basis of the prediction of crack formation.

The choice of rational adjustment of the chemical composition of iron melted in an electric arc furnace on the basis of technological audit of serial films

The object of research in the work is cast iron of the SCh20 grade according to GOST 1412-85 (DSTU EN 1561, EN-GJL-200), which is melted in an electric arc furnace. In this work, the parameters of serial smeltings of cast iron used for machine-building castings were determined, which were used to select the content of elements of the chemical composition. The existing problem is that the impossibility of taking into account many factors influencing the formation of the chemical composition of cast iron during smelting leads to deviations of the chemical composition from the requirements regulated by the technical conditions. The main reason for this is the uncontrollability of the chemical composition of the charge materials and the difficulty of accurately determining the soot of the elements during the smelting process. This can lead to the formation of a shortage of cast iron, or to excessive costs for smelting, associated with the need for additional technological operations and the use of additional materials to eliminate detected deviations of the composition from the requirements. The procedure of technological audit of serial smeltings is proposed, the feature of which is a comprehensive assessment of the actual indicators of smelting. They include: mathematical expectations of the content of the elements of the chemical composition, estimates of their dispersions, root mean square deviations, systematic errors, scattering fields and deviations of the lower and upper limits of the content of each element from the lower and upper limits required by the technical conditions. The results of such an audit are the possibility of calculating corrective combinations of charge materials and ferroalloys, which eliminate inaccuracies in the calculation of the charge and the determination of the heat of the elements during the smelting process. As a result of the audit of a sample of 31 serial smelters, it was established that the average content of the elements C, Mn, Si, Cr exceeds the average required by technical conditions. These deviations are: +0.04 % C, +0.06 % Mn, +0.038 % Si, +0.06 % Cr. To compensate for these deviations, the following combination of charge materials and ferroalloys, which are introduced into the melt before delivering the cast iron to the casting area, is proposed: 44 kg of steel scrap +88 kg of recycled iron. The presented study will be useful for machine-building enterprises that have foundries in their structure, where iron is melted for the production of castings.

Experimental Study of a Representative Sample to Determine the Chemical Composition of Cast Iron.

In metallurgical practice, the material is considered of adequate quality if it meets the customer's expectations. It is necessary to take representative samples and perform quality testing to avoid financial and intangible losses. Sample contamination and matrix and surface quality play a significant role in the accuracy of chemical analyses. The purpose of this paper is to point out the advantages of specific methods of taking samples, such as immersion and spoon sampling of molten metal, and, in the experimental part, to assess the impacts of factors affecting the quality of the sampling. The influence of time of final sampling on determining the true amount of magnesium during a single melt and the influence of duration of mixing of molten cast iron on the accuracy of chemical analysis of the control sample were investigated. It is important that the time between the modification and casting of the liquid cast iron from the casting ladle be as short as possible. This is because the magnesium burns out and thus the chemical analysis of the sample taken is not accurate. Another important factor is ensuring the melt before sampling is homogenized and has the minimum prescribed temperature (1420 °C). Increasing sample collection time will cause changes in its chemical composition.

Effects of NbC addition on mechanical and tribological properties of AlCrFeNi medium-entropy alloy

AlCrFeNi medium-entropy alloy (MEA) without expensive Co has demonstrated superior properties over the well-known AlCoCrFeNi high-entropy alloy. We added NbC particles to the MEA to make NbC-reinforced MEA alloys or MEA-matrix composites, and evaluated their wear resistances and mechanical properties. The materials showed considerably improved performance. To well judge the NbC-MEA for realistic applications, the wear resistance of the NbC-MEA samples was compared with those of a few industrial wear-resistant materials, e.g., high-Cr cast iron (HCCI) and WC-Co composites. It was demonstrated that the MEA samples with 40–60 vol% NbC exhibited markedly higher wear resistance than the reference materials, and the MEA demonstrated high superiority over the widely used Co as the metal-matrix for developing wear-resistant metal-matrix composites (MMCs).

Mechanism Analysis for the Enhancement of Low-Temperature Impact Toughness of Nodular Cast Iron by Heat Treatment.

The low-temperature impact toughness of nodular cast iron can be significantly enhanced by heat treatment, and thus meet the severe service requirements in the fields of high-speed rail and power generation, etc. In order to explore the enhancement mechanism, microstructure, hardness, composition and other characteristics of as-cast and heat-treated nodular cast iron is systematically tested and compared by optical microscopy, microhardness tester, EBSD, SEM, electron probe, and impact toughness testing machine in this study. The results show that heat treatment has little effect on the morphology and size of graphite in nodular cast iron, ignores the effect on the grain size, morphology, and distribution of ferritic matrix, and has little effect on the hardness and exchange of elements, while it is meaningful to find that heat treatment brings about significant decrease in high-angle grain boundaries (HAGB) between 59° and 60°, decreasing from 10% to 3%. Therefore, the significant enhancement of low-temperature impact toughness of nodular cast iron by heat treatment may result from the obvious decrease in HAGB between 59° and 60°, instead of other reasons. From this perspective, the study can provide novel ideas for optimizing the heat treatment process of nodular cast iron.

The effects of periwinkle shell reinforcement in a grey cast iron metal matrix composite (using powder metallurgy)

Grey cast iron is widely used in various engineering applications because of its cost effectiveness and beneficial properties. However, due to the presence of graphite in its microstructure its capacities are limited. Various engineering methods such as compositing are researched into that may minmize these limitations and give the metal a wider scope of application. In this project, periwinkle shell reinforced grey cast iron composites were manufactured using the powder metallurgy method. The weight percentage of periwinkle shell in the composite was varied in the following pattern: 5 %, 10 %, 15 %, 20 % and 25 %. The manufactured samples were subjected to various tests namely: wear test, hardness test, tensile test, impact test and compressive test. It was observed that the reinforcing grey cast iron with periwinkle shells improved the wear rate, tensile strength and impact toughness of the matrix but has adverse effects on its hardness and compressive strength.

Mechanical, tribological, and morphological properties of SiC and Gr reinforced Al-0.7Fe-0.6Si-0.375Cr-0.25Zn based stir-casted hybrid metal matrix composites for automotive applications: Fabrication and characterizations

The main goal of this research is to meet the demanding need for developing lightweight materials with improved properties that are appropriate for several engineering applications. The investigators proceeded to considerable efforts to assess the mechanical, micro-structural, and tribological characteristics of Al-0.7Fe-0.6Si-0.375Cr-0.25Zn/10 wt%SiCP/3 wt%GrP-MMC, Al-0.7Fe-0.6Si-0.375Cr-0.25Zn/15 wt%SiCP/5 wt%GrP-MMC, and Al-0.7Fe-0.6Si-0.375Cr-0.25Zn/20 wt%SiCP/8 wt%GrP-MMC based hybrid metal-matrix nano-composites (HMMC's). These hybrid aluminum matrix nano-composites were fabricated using the liquid processing stir casting method for automobile, aviation, defense, and chemical handling sectors owing to their superior strength, and higher thermal conductive properties. The machinability of Al-0.7Fe-0.6Si-0.375Cr-0.25Zn/(SiCp + Grp) - MMC has received limited attention to date. Owing to its exceptional characteristics, this hybrid composite could take the role of cast iron or aluminum composites in a wide-variety multitude of engineering applications. The Mechanical properties of fabricated Hybrid-MMCs have been examined along with tribological properties & other factors, affecting the tensile strength of cast composites in this study. Additionally, the characterization has been performed through X-ray Diffraction (XRD), Energy Dispersive Spectrum (EDS), Scanning Electron Microscope (SEM), and Optical Microscopy. The fabricated samples of hybrid metal matrix nano-composites of Al-0.7Fe-0.6Si-0.375Cr-0.25Zn matrix have been tested for microstructure analysis, micro hardness test, density, tensile strength, and grain size. Microstructure study clears the claim of uniform distribution of SiC & Graphite particles in Al matrix alloy. An average tensile strength has been recorded as 258 MPa and a percent-elongation of 4.6 during the tensile test. Tensile-fractography findings have portrayed the intrinsic fractured-rupture microstructure of tensile-tested samples that seemed to have particle deformation breakage and pull-outs. The density of Al/(SiCp + Grp)-MMCs have been found to be 2.76 g/cm3 whereas the average hardness has been recorded at 120HV. An increase in graphite content in Al/SiC-MMC's provides a significant improvement in friction coefficient as well as a reduction in wear rate. Findings have observed that the wear rate is increased with increasing the sliding speed, however, it is almost constant between 300 and 600 rpm, and beyond this wear rate increases drastically. Likewise, the coefficient of friction also shows a considerable increase with the increase in sliding speed. As the composition of graphite in the material increases, a considerable decrease in the wear has been noted down because of the presence of tribo-layer formed between mating surfaces. A high value of applied load and high rotating speed imposed high deformation of the surface and increase in frictional force, as a result, an increase in wear rate. Wear rate increases with the increment in load during the wear test, while friction coefficient decreases. Hence, the development of HMMCs with better mechanical, microstructural, and tribological properties that can be utilized as cast iron or aluminum composites in a diverse spectra multitude of engineering applications involving the study's scientific insights and technological developments. Manufacturers in the myriads of industries, including aerospace, ground-transportation, thermal management, industrial, recreational, and infrastructure, could profit inventors/producers from the findings of the current study.

Numerical Investigation of the Thermal Effect of Material Variations on the Brake Disc

Braking is one of the most critical systems for ensuring the safe driving performance of motor vehicles. Among the components that constitute the braking system, the disc is the one with the highest risk of wear. When the braking system is engaged, the physical contact between the brake pad and the disc leads to the generation of high pressure and high temperature. This released heat shortens the material's lifespan. The wearing or fracturing of the brake disc can result in a significant safety vulnerability. Therefore, it is desired for the discs to have better heat dissipation to increase their longevity. In this study, two different designs of brake discs were first examined thermally using the computational fluid dynamics (CFD) method. Subsequently, numerical analyses were conducted under the same boundary conditions by selecting the disc geometry with superior heat dissipation performance and using different materials. The results obtained from the analyses were compared and interpreted. The materials utilized in the study were grey cast iron, carbon steel, stainless steel, and carbon-carbon composite. As a result, it was observed that the carbon-carbon composite exhibited higher resistance to elevated temperatures.

Напрями розвитку методології регулювання хімічного складу і властивостей чавуну в ливарному виробництві на базі ймовірнісного підходу

From the standpoint of systemic and structural-functional approaches, the state and prospects of development of the methodology for regulating and predicting the chemical composition and mechanical properties of grey synthetic cast iron intended for casting production are analysed. Attention is focused on the key intersections of the technological process of manufacturing castings for critical applications. The features, disadvantages, and advantages of the known methods for calculating the charge and adjusting the percentage of chemical elements in the cast iron composition directly during its melting are considered. Ways to take into account the instability of the chemical composition of scrap metal, ferroalloys, and other materials when forming the charge to ensure the quality of pig iron in accordance with the requirements of finished product standards are shown. A promising way to solve this problem in foundry is to use a probabilistic approach and the Monte Carlo method. The article presents formulas for calculating the strength and hardness of cast iron castings with lamellar graphite depending on its carbon equivalent and degree of eutecticity. The peculiarity of the proposed formulas, which gives them enhanced reliability and validity, is that the carbon equivalent and the degree of eutecticity of cast iron in them are determined by the Monte Carlo method using a probabilistic approach with regard to the consideration of the ranges of variation of the content of chemical elements in the cast iron composition regulated in the standard for foundry products. It is noted that the widespread use of thermal derivative express analysis of liquid cast iron in industry is constrained by the lack of a database of reference cooling curves with certain property indicators (chemical composition, microstructure, mechanical and other properties) of cast irons at foundries. Keywords: foundry, cast iron, chemical composition, properties, control, regulation, methodology.

Optimizing the Chemical Composition of Brake Shoes According to the Hardness Recommended by the Product Standard.

Optimizing the chemical composition of phosphorus cast iron for the manufacture of brake shoes, which are used in the rolling stock, is based on specific tests, and the results must be within the specified limits of railway standards. This paper presents the processing of data taken from an economic agent producing brake shoes-with chemical composition and hardness values determined through the Brinell method-as well as optimizing these data by obtaining optimal variation intervals. These technological intervals are useful in the case of foundries in order to obtain superior products from a qualitative point of view.

Прогнозування механічних властивостей сірого чавуну (ймовірнісний підхід)

The article analyses the literature on the dependence of mechanical properties (tensile strength, hardness, etc.) of grey cast iron castings on the percentage of chemical elements in its composition and on the carbon equivalent, degree of eutecticity, and the ratio of carbon to silicon content. On the example of assessing the mechanical properties of cast iron with lamellar graphite, these dependencies are considered in the probabilistic aspect. It is emphasised that even within the same ranges of percentage of chemical elements in cast iron, as defined in standards or specifications, the values of its carbon equivalent, eutecticity, and the ratio of carbon to silicon content may be different. On the other hand, with different percentage ratios of chemical elements in the cast iron composition, the values of its carbon equivalent may be the same. It is shown that the conclusion about the presence or absence of correlation, in particular, between the hardness of castings and the carbon equivalent of the grey cast iron from which they are made, depends on the interval of variation of this argument. If the variation in the hardness of castings is significant and the interval for changing its carbon equivalent, calculated according to the chemical composition of cast iron specified in the standard for a particular casting product, is relatively short, the dependence of cast iron hardness on its carbon equivalent may not be evident. The disadvantage of the known empirical formulas intended for the approximate calculation of the tensile strength and hardness of cast iron based on its carbon element and eutecticity is the uncertainty of the choice of these indicators. It is proposed to use in such formulas the mathematical expectations (average values) of the carbon equivalent, eutecticity degree and the ratio of carbon to silicon content determined in the probabilistic approach using the Monte Carlo method. It is recommended that the distributions of chemical elements in grey cast iron within their intervals provided for in the standards be considered in accordance with the normal Gaussian law. Based on the information on the chemical composition and properties of grey cast iron with lamellar graphite smelted in accordance with the requirements of DSTU 8833-2019, the dependence of the carbon equivalent and the degree of eutecticity on the ratio of carbon to silicon content, as well as the strength and hardness of castings on these characteristics of the chemical composition of cast iron, have been identified. The formulas for determining the mechanical properties of grey cast iron with lamellar graphite have been calculated. Keywords: cast iron, casting, chemical composition, carbon equivalent, carbon to silicon ratio, degree of eutecticity, hardness, strength.

КОРРЕЛЯЦИОННАЯ ЗАВИСИМОСТЬ ВЛИЯНИЯ СТРУКТУРЫ И ФОРМЫ ВКЛЮЧЕНИЙ ГРАФИТА ЧУГУНА СТАЛЕРАЗЛИВОЧНЫХ ИЗЛОЖНИЦ НА ИХ СТОЙКОСТЬ

The resistance of cast irons to destruction is largely determined by the shape of graphite inclusions, the size of graphite inclusions, the number of graphite inclusions, and the nature of the distribution of graphite inclusions. Studies of the stress-strain state, performed on models of gray and modified cast iron for bending, allow us to evaluate the advantages and disadvantages of the obtained structure and shape of graphite inclusions. The application of the method of mathematical statistics with obtaining an empirical dependence of the influence of the structure and form of the graphite inclusion of cast iron on the durability of the molds will allow optimizing the chemical composition of cast iron and increasing the number of fillings. The use of the method of analytical statistics in research, such as correlation analysis performed on physical models of cast iron, established the correlation dependence of the influence of the structure and shape of graphite inclusions of cast iron in steel casting molds on their durability.

Оцінка підходів до прогнозування властивостей синтетичного чавуну у ливарному виробництві

An overview of approaches to assessing the dependence of the mechanical properties of products made of synthetic iron smelted in induction crucible furnaces on the content of carbon and the content of silicon in its chemical composition, as well as on the carbon equivalent, the degree of eutecticity, and the ratio of the carbon content to the silicon content is given. The statistical parameters of the percentage distributions of the specified elements in the chemical composition of cast irons with lamellar graphite produced in accordance with the requirements of DSTU 8833-2019 were analyzed. The values ​​of the carbon equivalent of the chemical state of these cast irons and the values ​​of their degree of eutecticity were calculated according to common formulas for determining these indicators using the Monte Carlo method and using a probabilistic approach taking into account the content of each element in the chemical composition of cast iron. It is emphasized that, from a probabilistic point of view, the values ​​of the carbon equivalent and the degree of eutecticity may not coincide in different batches of cast iron, even with the same values ​​of the percentage content of chemical elements in its composition. It is shown that with an increase in the carbon equivalent and the degree of eutecticity, the strength and hardness of cast iron produced in accordance with DSTU 8833-2019 decrease. As the carbon content and carbon equivalent increase, the ratio of carbon content to silicon content decreases. In industrial batches of cast iron brake pads and «Khanin wedge» manufactured in accordance with GOST 30249-97 and GOST 34503-2018, the hardness of these products does not depend on the carbon equivalent due to the small range of the carbon equivalent values. Keywords: foundry products, cast iron, chemical composition, carbon equivalent, ratio of carbon content to silicon content, degree of eutecticity, hardness, strength

Interface characteristics and wear resistance of Ni-B4C plated ZTA reinforced high chromium cast iron composite

A chemical composite plating of Ni-B4C was used to prepare the surface-modified zirconia toughened alumina (ZTA) ceramic particles. The ceramic preforms were prepared by the plated ZTA and sodium silicate solution binder, followed by casting infiltration to prepare the ZTA particles reinforced high chromium cast iron (HCCI) composites. The result reveals that a distinct interface layer forms at the ZTA/HCCI interface, which consists of phases of ZrB2, FeB, Fe2B, and NaSiO4. The interfacial wettability between ZTA and HCCI is improved by the diffusion and reaction of Ni and B4C. The wear test reveals that the Ni-B4C plated ZTA particles can effectively improve the wear resistance of the ZTA/HCCI composite, and the wear rate of the composite is decreased to 11.6% of HCCI.

Modern Compositions of Cast Iron Used for Pouring Anodes of Aluminum Electrolyzers

The purpose of this work is to review modern foreign experience to investigate cast iron used in the installation of anodes for aluminum electrolysis production at JSC «Kazakhstan Aluminium Smelter». In the course of the study, the chemical composition of cast iron was analyzed and the selection of experimental cast iron compositions was carried out. The research revealed that one of the causes of the problem of incomplete removal of cast iron from steel nipples of anode holders after the dismantling of cinders and high voltage drop in the contact nipple – anode is the chemical composition of cast iron. The requirements for cast iron for casting anodes have been determined. It is established that to achieve positive results it is recommended to use cast iron of stable composition with low crystallization shrinkage and low phosphorus content; increased fluidity

Density distribution of seals and movement of powders during pressing in a closed mold

The data on the distribution of the density of seals made of cast-iron composites and the movement of particles in closed press molds during cold pressing are presented. The influence of the kinematics of the shape-forming elements of the press mold on the distribution of density along the height of the "sleeve" type seal is estimated. The deviation from the average value of the pressing porosity along the height at two-sided pressing is less than the deviation at one-sided pressing. A mathematical analysis of the dependence between the billet pressing pressure and the compaction mechanism for different pressing options is presented. Keywords: density, powder movement, pressing scheme, pressing pressure, matrix, rod, press mold, punch. afetceferova8@gmail.com