Ingot Casting Research Articles

Effect of grain size and orientation on magnetron sputtering yield of tantalum

The electron beam melting (EBM) technique was employed to prepare ultra-highly pure (99.999 wt%) Tantalum (Ta) cast ingot for application in chips. Subsequently, the Ta cast ingot were forged, rolled, and annealed with different durations to gain three different grain sizes (centimeter scale, 99.8 μm, and 36.7 μm). Sputtering experiments conducted under identical conditions revealed that the rolled target (36.7 μm) film deposition rate was increased by 60.6 % compared to the cast ingot target with a centimeter-scale grain size (columnar crystal). Ta targets with a fine grain size and homogeneous distribution demonstrate superior film deposition performance. The sputtering rate is directly related to the atomic packing density of grains. The (111)-oriented grains of BCC targets (Ta target) exhibit sputtering resistance, and the order of sputtering rate of Ta atoms was S(101) > S(001) > S(111).

Digital heating method (DHM) for Ga-In-Sn alloy directional solidification

This study aimed to improve the precision and flexibility of temperature field control in conventional directional solidification (D–S). We propose an innovative digital heating method (DHM), which arranges microheating elements on the crucible surface, allowing for rapid and precise control. Each element is independently controlled by “on” and “off” states, enabling flexible D–S control and energy efficiency. Through mathematical modelling, we established the theoretical feasibility of DHM. In the experiments, a low-temperature Ga-In-Sn alloy was used as the experimental material in a polymethyl methacrylate (PMMA) crucible, and heating elements with different densities and layouts were tested for D–S. The main findings are as follows: First, DHM successfully achieves D–S and can form phase transition interfaces of different morphologies. Second, different element densities and layouts have minimal impacts on normal ingot casting, providing higher design flexibility. Additionally, we discovered that a staggered row layout of heating elements accelerates the solidification rate, whereas a staggered column layout favours the solidification of flat phase transition interfaces. This study presents an innovative approach for D–S heating and provides a low-carbon solution for future research in this field.

Effects of grain size, dislocation density, and texture type on the etching behavior of Cu target in magnetron sputtering process

Abstract Copper thin film is commonly applied in the microelectronics and battery industries, and environmentally friendly magnetron sputtering process is one of the main coating processes. The effects of grain size, dislocation density, and texture type of Cu target on sputtering efficiency were researched in this work. High-purity copper cast ingots were rolled into plates. Pieces were then cut from different surfaces of the plates and assembled into the targets named as Target 1, Target 2, and Target 3 for magnetron sputtering. To investigate the etching behavior of the three targets, EBSD technology was utilized for analysis, and the micro-morphologies of the etching grooves were observed using SEM. After the sputtering process, the weight loss rate and etching depth of the various targets were measured to compare the respective sputtering efficiency. Target 1 exhibited the highest sputtering weight loss rate at any time period compared to Target 2 and Target 3, and reached its maximum depth after every 15 minutes of sputtering. In the first 45 minutes, the etching depth of Target 2 was slightly greater than that of Target 3. While the etching depth of Target 3 increased significantly in the last 15 minutes compared to that of Target 2. The most significant factor influencing the sputtering efficiency of the target material was grain size, with finer grains leading to higher sputtering efficiency. The dislocation density had a greater impact in the first 30 minutes, but the texture type became more important as the sputtering process continued.

The Influence of Er and Zr on the Microstructure and Durability of the Mechanical Properties of an Al-Mg Alloy Containing 7 wt.% of Mg.

Al-Mg alloys are characterized by permanent solid solution hardening and can additionally be work-hardened. The high mechanical properties of Al-Mg alloys with above-standard Mg content obtained after plastic deformation processes decrease over time. The addition of minor alloying elements like Er or Zr is an alternative method to improve the durability of mechanical properties and increase the strength of Al-Mg alloys due to densely and evenly distributed dispersoids being formed. In this paper, Al-Mg alloys with above-standard Mg content (7 wt.%) and Zr and Er micro-alloying elements and their influence on the microstructure and durability of the mechanical properties were examined. The cast ingots of AlMg7 alloys were characterized by a smooth surface without cracks. The plastic deformation process in a static compression test resulted in an about 60 HBW increase in the Brinell hardness of all the deformed alloys relative to casting. It was revealed that the addition of Er and Zr significantly improved the mechanical properties and durability of the mechanical properties of the Al-Mg after annealing. The addition of Er or Zr slightly restrained the decrease in the Brinell hardness after annealing but did not inhibit it.

The Making of Roman Lead Ingots. Their Casting by Experiment and the Archaeological Evidence

Casting experiments in Brilon-Hoppecke (North Rhine-Westfalia, Germany) in 2011 and 2012 as well as in 2015 aimed to reconstruct the production of Roman lead ingots with the help of archaeological experiments on the one hand; on the other hand, traces of the moulding process on the Roman lead ingots themselves and the epigraphic evidence were examined to provide further information on the production process. The results of this research, suggest that most of the lead ingots were very likely cast in clay sand moulds which almost completely disintegrated after the ingots had been removed. In a few cases, wood could be verified as the material for the moulds. Finally, all known artefacts associated with the casting of lead ingots have been critically examined and reinterpreted.

Excellent tribocorrosion resistance in artificial seawater of high entropy alloy FeCrNiCoAl coating prepared by HVOF

In marine environments, steel friction pairs undergo significant degradation due to the combined effects of wear and corrosion, known as tribocorrosion. This study investigates the tribocorrosion behavior and mechanisms under high loads of a High Entropy Alloy (HEA) FeCrNiCoAl coating applied by HVOF spraying, as well as cast ingot FeCrNiCoAl and 304SS samples, in artificial seawater. The investigations were conducted using electrochemical methods and in situ wear- electrochemical techniques. The tribocorrosion rate of the HVOF coating is approximately 1/5 that of the HEA cast ingot and 304SS samples. This is attributed to the coating's high hardness and the supporting and isolating effects of its oxide layers between splats. An intriguing finding is that the Open-Circuit Potential (OCP) trough value of the HVOF coating coincides with the peak Coefficient of Friction (COF) value during tribocorrosion in artificial seawater. This is due to the exposure of fresh surfaces following the local peeling off of flattened particles. Furthermore, the coating exhibits high re-passivation capabilities during wear because of high oxygen content in the coating. In comparison to corrosion, wear-induced material loss was identified as the primary contributor (≥ 99.8 %) to mass loss in both HEA cast ingot and coating samples. Optimizing the quantity and morphology of the HVOF coating has the potential to further enhance its tribocorrosion resistance. This study lays the foundation for developing advanced tribocorrosion-resistant coatings for use in seawater environments.

Formation of seaweed morphology and enhancing mechanical properties of an A356 alloy by directional solidification

In the present work, regular dendrite and seaweed pattern are produced by controlling the crystal orientation during directional solidification of an A356 aluminium alloy. These morphologies and growth orientation were investigated by electron backscatter diffraction (EBSD), and the results showed that the seaweed pattern mainly prevailed under the (100)[011] orientation. At the same time, the effects of seaweed pattern in the properties of A356 alloy were analysed by room temperature tensile test. It was found that the elongation and toughness of the samples reached 20% and 36J/m3, respectively, for the seaweed; 13% and 24J/m3, respectively, for the regular dendrites; and 8% and 14J/m3, respectively, for the cast ingot. Compared with the regular dendrite samples, the seaweed pattern obtained relatively excellent elongation and toughness. By using scanning electron microscopy (SEM), it is found that the distribution of eutectic silicon particles in seaweed morphology sample is more refined and uniform, which is the main reason for these enhancements.

High and very high cycle fatigue behavior of an additive manufactured hot-work tool steel

In the present study, the fatigue response of an additive manufactured H13 type hot-work tool steel is investigated across the High Cycle Fatigue (HCF) and Very High Cycle (VHCF) regimes. The primary focus encompasses the interpretation of fatigue strength models, the defect type analysis along with a detailed examination of crack initiation and growth mechanisms. Despite the tremendous development in AM technology, experimental data regarding advanced mechanical properties, and particularly fatigue behavior, are still limited. Here, microstructural analysis of a modified AMed H13 hot-work tool steel, a combination of HCF and VHCF testing methodologies implemented for the characterization of the fatigue behavior, as well as a thorough fractographic analysis of the fractured surfaces were performed. Results are compared with historical data of a conventionally ingot cast and forged grade to assess the influence of the AM process on the fatigue response of H13 hot-work tool steels. It proves to be comparable to the conventionally manufactured grade, showcasing the potential utilization of AM in the production of components used in high-demanding applications, and in hot work tooling applications. However, the type of critical defects identified in the AM grade was found to be process-induced, emphasizing the need to optimize process parameters to reduce both the number and size of defects and also to ensure component reliability and high performance in various industrial applications.

The effect of differing Y concentrations on the evolution of the structure and mechanical properties of FeCrAl alloy

The influence of different Y concentrations on the evolution of the structural and mechanical properties of FeCrAl alloys is investigated in this work. The ingot casting process was used to produce alloys with Y mass fractions of 0%, 0.03%, and 0.25%, respectively. They were then annealed for 15 min at 850°C, 950°C, and 1050°C before being quenched by water to room temperature. Microstructure and mechanical properties were analyzed using OM, EPMA, EBSD, and tensile tests. The addition of 0.03% Y to FeCrAl alloy and annealing at 850°C resulted in the greatest overall performance of the alloy. This had a tensile strength of 635.62 MPa, yield strength of 465.48 MPa, and elongation of 27.04%. With an increase in Y concentration or annealing temperature, the tensile, yield, and elongation properties decrease. This phenomenon can be attributed to the incorporation of Y, which creates a fine Y-rich second phase in the alloy. These phases act as heterogeneous nuclei, pinning the grains during solidification, effectively reducing grain growth and refining the grains. Grain refinement and an increase in the number of grain boundaries hinder dislocation movement, thereby enhancing the alloy's tensile and yield strength. Simultaneously, this prevents the disappearance of α-fiber textures and the creation of γ-fiber textures during recrystallization and reduces the strength of the γ-fiber textures in the alloy microstructure. However, as the annealing temperature increases, microstructure grain growth and the number of grain boundaries decrease. Moreover, higher Y concentrations result in the formation of large, striated Fe-Y phases, which impair the forming properties of the alloy and consequently reduce its tensile properties. Therefore, future research should focus on effectively avoiding the formation of coarse second phases in the microstructure of FeCrAl alloy to enhance its overall performance.

Enhancing Mechanical Properties of Cast Ingot Al6061 Alloy Using ECAP Process

AbstractGrain refinement and mechanical property enhancement of cast ingot aluminum 6061 alloy were achieved using equal-channel angular pressing (ECAP) at room temperature, employing route A and route R types. Analytical, finite element and experimental methods were utilized to investigate the alloy’s deformation behavior under the ECAP process. The tensile tests conducted at room temperature demonstrated a significant increase in strength with an increasing number of pressings, reaching 44.23, 53.19, and 56.7% for 1-pass, route A, and route R types 2-passes of the ECAP process, respectively. However, ductility, as indicated by elongation, gradually decreased after the first pressing. Electron backscatter diffraction was employed to reveal submicrometer grain sizes resulting from the ECAP process. The grain structure showed substantial improvement under route A and route R types at a 2-passes ECAP process. Wear tests conducted under loads of 10 and 25 N showed an increase in the coefficient of friction within the minimum wear loss intervals. Rockwell hardness also exhibited a significant increase of 119.3, 176.3, and 164.8% at 1-pass and 2-passes using routes R and A, respectively. As part of the evaluation, analytical models were computed using Python, and finite element simulations were performed using ABAQUS software. The results from analytical and finite element simulations demonstrated good agreement with the experimental data.

Development of a methodology for determining the content of non-metallic inclusions in steel

As part of the study, a method was proposed for assessing the metal purity for non-metallic inclusions using optical emission spectrometry. To assess the content of non-metallic inclusions in the slabs, two columns of metal were selected from two slabs of low-alloy metal deoxidized with aluminum. Each column was divided into seven samples in the direction from the small radius of the continuously cast ingot to the large one. We studied these samples to assess metal contamination with non-metallic inclusions using quantitative optical metallography according to ASTM E1245-03, fractional gas analysis (FGA) and optical emission spectral analysis PDA. Analysis of the samples according to ASTM E1245-03 standard showed that in all samples the percentage of oxides and sulfides is on average 10 and 90 %, respectively. According to the results of FGA, it was concluded that such non-metallic oxide inclusions as aluminates predominate in the metal samples of both ingots. A comparison was made between the results of the determination of oxygen in non-metallic inclusions obtained by FGA method and the number of sparks in inclusions at the analysis by PDA method; analysis of the dependencies showed that there are two clearly defined point distributions. To carry out PDA analysis, a program was deve­loped that allows determining the number of inclusions of various types and calculate their volume fraction.

Numerical simulation study on solidification proceoss of titanium slab ingot by electron beam cold hearth melting

Abstract Titanium and titanium alloys are key basic support materials in the field of engineering technology and high technology, and are widely used in the fields of natural gas transportation, chemical corrosion, and marine development. Titanium alloy ingots are often prepared with more solidification defects such as surface cracks and cold shuts, resulting in lower utilization of titanium metal and higher cost of titanium products. The root of this is the lack of in-depth knowledge of the ingot melting and casting process, and the failure to control the thermal conditions of the billet in the molding process within a reasonable range. In this study, based on the Lagrange Euler algorithm, combined with ProCAST finite element software to establish a numerical model, revealing the solid-liquid interface morphology, the length of the transition region, and the change rule of thermal stress under the influence of different process parameters in the solidification process of titanium slab ingot. The results show that with the increase in pulling speed, the depth of the solid-liquid phase line and the width of the mushy zone of slab ingot increase, and the length of the transition region grows. With the increase in casting temperature, the depth of the solid-liquid phase line of the slab ingot decreases, and the mushy zone gradually becomes narrower. The casting temperature and pulling speed are positively correlated with the value of the thermal stress equivalent stress in slab ingots, and the probability of cracks in the corners and ingot surface is higher. This study provides effective theoretical guidance for the realization of stable mass production of high-quality titanium slab ingot.

Mathematical modeling of the flat ingot casting process or solving automation problems

Aluminum alloys are widely used in the production of aircraft due to their strength, lightness, corrosion resistance, and necessary electrical conductivity. At the same time, aluminum ingots used in further processing of the space industry must be of high quality. Technological problems and defects arise when temperature, speed, and other technological parameters of casting are not observed, or when modes change. At the same time, foundry processes are partially automated; the human factor significantly affects product quality and work safety. Therefore, automation of these complex processes using mathematical models to predict casting parameters is an urgent task. The goal of the work is to create mathematical models available for use in automated process control systems (APCS), as well as for the development of a digital twin. The work presents simplified formulas for modeling the temperature distribution of an aluminum ingot during the casting process, cooling the metal when moving along a metal path, and test calculations of the temperature distribution inside the ingot when the ingot reaches a fixed length. The results of this work can be used to improve the efficiency and accuracy of controlling the process of casting aluminum ingots, to eliminate emergency situations.

Adaptive Real-Time Tracking of Molten Metal Using Multi-Scale Features and Weighted Histograms

In this study, we study the tracking of the molten metal region in the dross removal process during metal ingot casting, and propose a real-time tracking method based on adaptive feature selection and weighted histogram. This research is highly significant in metal smelting, as efficient molten metal tracking is crucial for effective dross removal and ensuring the quality of metal ingots. Due to the influence of illumination and temperature in the tracking environment, it is difficult to extract suitable features for tracking molten metal during the metal pouring process using industrial cameras. We transform the images captured by the camera into a multi-scale feature space and select the features with the maximum distinction between the molten metal region and its surrounding background for tracking. Furthermore, we introduce a weighted histogram based on the pixel values of the target region into the mean-shift tracking algorithm to improve tracking accuracy. During the tracking process, the target model updates based on changes in the molten metal region across frames. Experimental tests confirm that this tracking method meets practical requirements, effectively addressing key challenges in molten metal tracking and providing reliable support for the dross removal process.

Mechanical Properties and Wear Resistance of Biodegradable ZnMgY Alloy

Biodegradable metallic materials are gaining attention for medical applications in short-term implants (15–500 days) because of their good mechanical properties, biocompatibility, and generalized corrosion. Most medical applications involve implant wear processes, particularly for bone fractures. Parallelepipedic specimens (dimensions 50 mm × 10 mm × 3 mm) were obtained by cutting the hot-rolled material processed from cast ingots of ZnMgY. To test the tribological performance of these stationary specimens, they were placed at the upper point of the machine’s tribological contact. The rotating lower disk of the AMSLER machine (AMSLER & Co., Schaffhouse, Switzerland) is manufactured from AISI 52100 bearing steel with a 62–65 HRC hardness and a diameter of 59 mm both radially and axially. Frictional torque is the parameter that is measured. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used to analyze the worn areas. The material behavior in the normal and wear states upon immersion in simulated body fluid (SBF) was evaluated.

ПОЛУЧЕНИЕ ЛИТЫХ СТАЛЬНЫХ ЗАГОТОВОК ДЛЯ КУЗНЕЧНОГО ПЕРЕДЕЛА В УСЛОВИЯХ МАШИНОСТРОИТЕЛЬНОГО ПРЕДПРИЯТИЯ

The results of the development (for the conditions of a machine-building enterprise) of the main technological solutions for the production of round steel ingots weighing 500 kg for forging are presented. 3D models of technological equipment and ingots of circular cross-section have been developed for pouring into reusable metal and disposable sand molds. In the LVMFlow software package (using the example of steel 45), computer modeling of casting and solidification of model ingots was performed. Industrial approbation of the obtained results of computer modeling was carried out: round-section ingots were cast from 45 steel, from which forgings of the "flange" type were made and shipped to customers.

Role of Longitudinal Temperature Gradients in Eliminating Interleaving Inclusions in Casting of Monocrystalline Silicon Ingots

Infrared analysis reveals the presence of interwoven inclusions, primarily comprised of silicon nitride and silicon carbide, in the casting process of monocrystalline silicon ingots. This study investigates how the longitudinal temperature gradient affects the removal of inclusions during the casting of monocrystalline silicon ingots through simulations and comparative experiments. Two monocrystalline silicon ingots were cast, each using different longitudinal temperature gradients: one employing smaller gradients and the other conventional gradients. CGSim (Version Basic CGSim 23.1) simulation software was utilized to analyze the melt flow and temperature distribution during the growth process of quasi–monocrystalline silicon ingots. The findings indicate that smaller longitudinal temperature gradients lead to a more robust upward flow of molten silicon at the solid–liquid interface, effectively carrying impurities away from this interface and preventing their inclusion formation. Analysis of experimental photoluminescence and IR results reveals that although inclusions may not be observed, impurities persist but are gradually displaced to the top of the silicon melt through a stable growth process.

Insulating refractories based on rice husk ashes functionalized by flame-sprayed alumina coatings for steel ingot casting

This study investigates a new insulating refractory material based on rice husk ashes (RHA) for its application in the steel ingot casting process. The excellent insulating properties of this material may improve heat- and energy balance during ingot casting. A flame-sprayed alumina coating is applied to provide chemical inertness of the substrate material against the steel melt. The refractoriness, oxidation resistance, phase evolution and thermal expansion of four different grades of RHA materials and phase evolution and thermal expansion of flame-sprayed alumina coatings are studied. The refractoriness of the RHA materials increased with increasing silica content, showing sufficient refractoriness up to 1600°C for SiO2>94wt%. Immersion tests with composite materials made from RHA substrate and a flame-sprayed alumina coating were successfully performed in a steel casting simulator. No deformation of the substrate material nor spalling of the flame-sprayed alumina coating was observed despite an immersion without preheating.

ЕКСПЕРИМЕНТАЛЬНЕ ДОСЛІДЖЕННЯ ТОЧНОСТІ ПРОКАТКИ НА СТАНІ 800

The purpose of the work is an experimental study of the process of square sections rolling on the rolling mill 800 to determine the influence of rolling parameters on the dimensions and length of the roll. During the study, variations in ingot mass, rolling dimensions, and rolling length were determined, regression equations and correlation coefficients were obtained for the dependence of rolling dimensions and length on the ingot mass, changes in interroll gap and time delay before the finishing stand. It was established that the ingot mass variates within significant limits - 638 kg, which is caused by the melt mass variations. Variations in the mass of the ingot within one ingot mold stool are caused by the dimensions of the ingot molds and are within 154 kg. Variations in the dimensions of the roll are carried out within the following limits: thickness - 1.0 mm, width - 0.5 mm, length - 5.3 m. The change of the interroll gap can be used to correct the length of the finished roll in a small range of lengths, if the mass variations occur within accuracy of ingot casting on one ingot mold stool. It is necessary to take additional measures to stabilize the weight of the ingot. The influence of delays in the rolling train, which occur during rolling and lead to instability of the rolling temperature regime, for this type of profiles does not significantly affect the dimensions of the cross section and the length of the roll.

Significance of segregation on grain refinement and property improvement in extruded Mg-Al-Mn alloy with moderate Al content

Two Mg-5Al-Mn (mass%, AM50) alloys having different microstructures were extruded, and the tension/compression properties were investigated. One was a lab-scale material, which had dense segregation of Al element, while the other was a commercial casting ingot with sparce segregation of Al element. The dense segregation led to significant grain refinement. The average recrystallized grain size was 5.0 μm, which resulted in the high proof stresses of 252 MPa, 211 MPa, and 178 MPa for the tension along the extrusion direction (ED), compression along the ED, and compression along the radical direction, respectively. When the extrusion was performed after homogenization, grain coarsening was apparent, leading to the significant decrease in strengths for the tension and compression, and both the lab-scale and commercial cast ingot exhibited similar properties despite the difference in the initial grain size.