Casting Operations Research Articles

Chlorination of HALEU regulus casting dross

A scoping study was performed for chlorinating dross formed during uranium casting operations. The purpose is to minimize the losses of uranium to dross wastes. The dross is primarily a mixture of uranium metal and uranium oxide with a minor fraction of crucible and crucible coating materials. The reaction chemistries were performed in a carrier salt of LiCl-KCl eutectic at 500 °C. The addition of FeCl2 chlorinated the uranium metal to UCl3, by reducing the FeCl2 to iron metal. After the uranium metal was chlorinated, zirconium metal was added to the salt. The residual FeCl2 chlorinated the zirconium metal to ZrCl4, by reducing the FeCl2 to iron metal. In turn, the ZrCl4 chlorinated the uranium oxide to UCl3, by converting the ZrCl4 to zirconium oxide. The effectiveness of the chlorination reactions was qualitatively verified by cyclic voltammograms that indicated the presence or absence of FeCl2 and UCl3 in the salt.

Influence of Different Submerged Entry Nozzles for Continuous Casting of Ultrathick Slab

Controlling the flow activity at the meniscus in the mold during the continuous casting of ultrathick slab is challenging due to the complex flow behavior, which is not extensively documented. Herein, a multiphase transient model of the ultrathick slab mold has been developed to describe the flow of molten steel, velocity distribution, and stream pattern at different submerged entry nozzle (SEN) outlets. The position of impact points and the fluctuation of liquid level are discussed as well. After ejecting from the port, the stream of the S‐shaped SEN splits into upper and lower streams. The upper stream moves to the liquid level, which improves the liquid level activity near the SEN. However, the reduced mainstream momentum alleviates the occurrence of slag layer exposure. Industrial application of the S‐shaped SEN results in uniform slag distribution and smooth casting operations.

The 2015–2019 excavation of the bronze foundry site at the Huanbei Shang City in Anyang, Henan

Abstract The Anyang Team of Institute of Archaeology, Chinese Academy of Social Sciences conducted five excavations of a bronze foundry site at the Huanbei Shang City from 2015 to 2019. A variety of archaeological features were discovered, ranging from the foundation built from calcareous nodules and rammed earth, bronze melting and casting area, refuse area, sacrificial pit, ash pit, well, and cache pit. Many artifacts related to metallurgy were also unearthed, including clay molds, models, cores, bellow nozzles, slag, furnace fragments, charcoal, bone gravers, and whetstones. The discovery of this bronze foundry site is of great value for the study of the Huanbei Shang City layout, the operation, and management of bronze casting, technological transmission, and other questions. Bronze casting technology at Huanbei Shang City was still in its early stages of development, but it laid a solid foundation for the later flourishing of the bronze civilization at Yinxu.

Physical modeling and numerical investigation of fluid flow and solidification behavior in a slab caster mold using hexa‐furcated nozzle

AbstractSlag entrapment from metal–slag interface during continuous casting operations has been a major area of concern for steelmakers globally. The presence of inactive regions in the upper region of the mold poses another challenge. Proper flow behavior of the molten metal coming out of the nozzle in the mold is required to overcome these challenges. Nozzle design greatly affects the flow pattern of the molten steel inside the mold. The present investigation is an attempt to study the flow and solidification behavior in a slab caster mold with the use of a novel‐designed hexa‐furcated nozzle using numerical investigation results. The casting speed and submerged entry nozzle (SEN) depth are varied to study the effect of these parameters on minimizing the inactive zones in the mold and the steel/slag interface fluctuations. The results show that the interface fluctuation increases at higher casting speed and lower SEN depth. The residence time distribution (RTD) analysis was also performed for different cases to investigate the flow behavior. The validation of the fluid flow and RTD curve inside the computational domain is carried out with the use of physical modeling.

Effect of TiC nano-treating on the fluidity and solidification behavior of aluminum alloy 6063

Wrought aluminum alloy AA 6063 is known for its favorable mechanical properties, corrosion resistance, and weldability in high-performance applications. Nonetheless, its limited fluidity hinders the cost-effective production of intricate structures through economical casting processes. To address this, a small fraction of TiC nanoparticles were dispersed into the AA 6063 melt to enhance its fluidity, eliminate hot cracking, and improve casting surface quality. Further investigation indicates that nanoparticles contribute to gradual latent heat release, grain growth restriction, and improved molten alloy wettability. The results demonstrate the potential of the emerging nano-treating technology in making traditionally difficult-to-cast alloys viable for low-cost casting operations to deliver products with enhanced high performance for numerous applications.

Application of Time Series for Casting Using Machine Learn Method

Time series forecasting plays a vital role in optimizing processes through many industries, and the casting for the domain is no exception. Casting processes suddenly require exact predictions to shine product quality, low waste, and optimize resource allocations. This paper discovers the application of machine learning methods for time series forecasting. It starts with an exact review of existing research, enjoying the critical role of correct forecasting in this field. The research leverages device learning techniques, adding autoregressive integrated walking average (ARIMA), Long Short-Term Memory (LSTM) networks and XGBoost, to model & guess time series data related to casting processes. A different and unique dataset is collected, again processed and used for experimentation. The results shows the ability and control of these machine learning methods in forecasting many possibilities of casting processes. Through a serious talk of the results and their real implications, these paper implies to the increasing body of memory in the space of time series forecasting for casting. The discovery offer insights into a feasibility of using machine learning to shows casting operations, improve product quality and optimize resource use. This research no only shows the potential of machine learning in the casting field but also shows as a foundation for further Discovery and application of advanced forecasting techniques in this domain.

Optimizing steel coil production schedules under continuous casting and hot rolling

In continuous steel casting operations, heats of molten steel are alloyed and refined in ladles, continuously cast and cut into slabs, and hot-rolled into coils. We present a mixed-integer program that produces a daily casting schedule and that is solved using state-of-the-art software for a 100% direct-charge steel mill; two casters concurrently produce slabs, which are rolled into coils at a single hot rolling mill. This model minimizes penalties incurred by violating plant best practices while strictly adhering to safety and logical constraints to manage risk associated with manufacturing incidents. An efficient formulation, combined with variable reduction and cutting planes, expedites solutions for small instances containing hundreds of variables and thousands of constraints by factors of at least two or three (and sometimes even 100); instances an order of magnitude larger along both problem dimensions suggest solutions that reduce costs incurred using plant best practices by as much as 40%.

In Situ and Real-Time Mold Flux Analysis Using a High-Temperature Fiber-Optic Raman Sensor for Steel Manufacturing Applications

Continuous casting in steel production uses specially developed oxyfluoride glasses (mold fluxes) to lubricate a mold and control the solidification of the steel in the mold. The composition of the flux impacts properties, including basicity, viscosity, and crystallization rate, all of which affect the stability of the casting process and the quality of the solidified steel. However, mold fluxes interact with steel during the casting process, resulting in flux chemistry changes that must be considered in the flux design. Currently, the chemical composition of mold flux must be determined by extracting flux samples from the mold during casting and then processing these samples offline to estimate the working chemical composition and, therefore, the expected properties of the flux. Raman spectroscopy offers an alternative method for performing flux analysis with the potential to perform measurements online during the casting process. Raman spectroscopy uniquely identifies specific chemical bonds and symmetries in the glassy flux by revealing peaks that are a fingerprint of the vibration modes of molecules in the flux. The intensities of specific peaks in Raman spectra can be correlated with the chemical composition of the melt and associated properties such as basicity and viscosity. This paper reports on the first use of a portable fiber-optic Raman sensor for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> Raman spectroscopic measurements of molten flux at 1400°C. The work demonstrates the advantages of fiber-optic Raman spectroscopy to document the structure and chemical composition of flux samples at temperatures typically encountered in the mold during continuous caster operation. Experimental results demonstrate that the composition-dependent Raman signal shifts can be detected at caster operating temperatures, and the use of high-temperature Raman analysis for in-line flux monitoring shows significant promise for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> detection of changes in flux composition and physical properties during casting.

Do names echo semantics? A large-scale study of identifiers used in C++’s named casts

Developers relax restrictions on a type to reuse methods with other types. While type casts are prevalent, in weakly typed languages such as C++, they are also extremely permissive. Assignments where a source expression is cast into a new type and assigned to a target variable of the new type, can lead to software bugs if performed without care. In this paper, we propose an information-theoretic approach to identify poor implementations of explicit cast operations. Our approach measures accord between the source expression and the target variable using conditional entropy. We collect casts from 34 components of the Chromium project, which collectively account for 27MLOC and random-uniformly sample this dataset to create a manually labelled dataset of 271 casts. Information-theoretic vetting of these 271 casts achieves a peak precision of 81% and a recall of 90%. We additionally present the findings of an in-depth investigation of notable explicit casts, two of which were fixed in recent releases of the Chromium project.

The Influence of Small Additions of Alloying Elements on the Hot Ductility of AHSS Steels: A Critical Review Part 2

In this paper, the influence of small additions of Cr, Mo, Cu, Ni, B, Ca, Zr, and Ce on the hot ductility of advanced high-strength steels (AHSS) has been reviewed. Most of these small additions have a positive effect in improving hot ductility on straightening during continuous casting operations and should be considered when problems with cracking in continuous casting are encountered. In many of these cases, the reason for these generally small but important improvements in hot ductility is not known with certainty, but the segregation of these elements to the austenite grain boundaries, strengthening the bonding, is often suggested.

Assessing operational performance in industrial billet casting using an instrumented mould

ABSTRACT In the present study, the operational characteristics of an industrial billet caster were investigated. Two billet moulds were instrumented with Fibre Bragg Grating (FBG)-based temperature sensors and run for their full lives of 320 h each under normal plant conditions doing open casting with oil lubrication. The heat fluxes and temperatures of the mould wall were used to study the peritectic nature of the grades cast. The data from the moulds were also used to understand the main resistances to heat transfer by comparing the variation in mould wall temperatures to the variation in liquid steel temperature through a cast. The impact of mould life on the heat transfer through the mould was also studied by comparing data of similar casting conditions over the whole life of the mould. The instrumented moulds were also used to study sticker breakouts. The classical breakout signatures were obtained in the temperature profiles in the breakout events. It was found that the hot spot associated with the temperature peak was moving down at a speed of around 0.7–0.75 times the casting speed. The usefulness of FBG-based temperature sensors for practical billet caster operations has been shown.

Liquid Core Detection and Strand Condition Monitoring in a Continuous Caster Using Optical Fiber

Real-time monitoring of the liquid core position during the continuous casting of steel has been demonstrated using low-cost distributed optical-fiber-based strain sensors. These sensors were installed on the containment roll support structures in the segments of a production continuous caster to detect the position of the solid-liquid interface and monitor the strand condition during the continuous casting. Distributed Fiber Bragg Grating sensors (FBGs) were used in this work to monitor strain at six roll positions in the caster. The sensor performance was first validated by comparing optical strain measurements with conventional strain gauge measurements in the lab. Next, optical strain measurements were performed on an isolated caster segment in a segment maintenance facility using hydraulic jacks to simulate the presence of a liquid core under the roll. Finally, the sensors were evaluated during caster operation. The sensors successfully detected the load increase associated with the presence of a liquid core under each instrumented roll location. Incidents of bulging and roll eccentricity were also detected using frequency analysis of the optical strain signal. The liquid core position measurements were compared using predictions from computer models (digital twins) in use at the production site. The measurements were in good agreement with the model predictions, with a few exceptions. Under certain transient caster operating conditions, such as spraying practice changes and SEN exchanges, the model predictions deviated slightly from the liquid core position determined from strain measurements.

Numerical simulation and mathematical modeling of the casting process for pearlitic spheroidal graphite cast iron

Abstract Fluidity, an essential parameter in casting operations, is influenced by the thermal properties of the alloy and the mold, pouring temperature, modification, and inoculation of the alloy. In this work, pearlitic spheroidal graphite cast iron (PSGI) was studied in terms of fluidity characteristics. The sand mold used had different section thicknesses. The alloy was cast at pouring temperatures changing between 1,360–1,480°C. Liquid metal quality ranged between 10 and 90% where the section thickness was changed from 1 to 5 mm. FlowCast simulation tool was used for the modeling of the tests. The analysis of variance results of the response surface model constructed between certain casting parameters and fluidity length have shown that the reduced regression equation is very accurate in terms of statistical indicators (predicted R 2: 0.99). The sensitivity analysis has shown that the section thickness is the most dominant parameter on the fluidity, while metallurgical quality is the least. The proposed model was also compared with the studies in the literature and it was seen that the results are well-matched. Therefore, it was suggested to use the proposed equation in order to estimate the fluidity results of PSGI without the need for real casting operations.

Study on asymmetry and temperature difference between different strands in 7-outlets tundish

ABSTRACT This paper addresses the problem of temperature difference between the different strands in a 7-outlets tundish of a steel plant by using physical modelling and numerical simulation methods. The problem of large temperature difference between different strands was solved and stability was achieved in the field production process. The parameters such as stagnation time and peak time by each stream were calculated by physical modelling and the optimized parameters based on temperature difference were implemented in the actual production process, which could predict an accurate temperature difference between strands in multi-flow tundish. The average temperature difference between side flow and intermediate flow of tundish was reduced from 15°C to 5°C by reasonable adjustment of flow control device between different strands, which provides basic support for improved billet quality, prevents breakout accident during continuous casting operation, reduces the pouring temperature and ensures the low-temperature rapid casting.

Influence of Alkaline Earth Metals on Structure Formation and Magnesium Alloy Properties.

The main aim of this work is to improve the structure and properties of the magnesium alloy ML5 by modifying it with alkaline earth metals (ALM). The separate and joint influence of calcium and barium on the macrostructure and microstructure of the alloy of Mg-Al-Zn system was investigated. The qualitative and quantitative estimation of the structural components was carried out. Alkali earth metals were included in complex intermetallic phases and serve as additional crystallization centers. Modification of magnesium alloys with alkaline earth metals is established in an amount of 0.05 to 0.1 wt. % increased the bulk percentage of intermetallic phases by ~1.5 times, shifting them towards smaller size groups while simultaneously forming spherical intermetallic phases located in the grain centre and serving as additional crystallization centers. In this case, grain size reduction and significant refinement of the alloy structural components were provided. The dependency of the separate and joint influence of alkali earth metals on the castings complex of properties of the magnesium alloy has been established. Thus, a separate modification of the ML5 alloy provided the maximum level of its strength and ductility with the addition of 0.1% Ca or Ba. The modification of the complex (0.1% Ca + 0.1% Ba) of the magnesium alloy decreased the dimensions of its structural components 1.5 times and increased the strength of the alloy by 20%, the ductility by 2 times and the long-term heat resistance 1.5 times due to the formation of the intermetallic phases of the complex composition. Linear dependences were obtained that describe the influence of the characteristics of the structural components of the modified magnesium alloy on its mechanical properties. The developed technology for modifying cast magnesium alloys with alkaline earth elements provides an improvement in casting quality and allows the reliability and durability of responsible casting operation.

A Review of the Brazeability of Low-Temperature and Nano-Reinforced Al-Based Brazing Filler Metals

Aluminum and its alloys are some of the most widely used materials for the brazing of parts in aerospace and automotive industries due to their excellent physical characteristics, e.g., good ductility, high strength-to-weight ratio, light weight, good corrosion and oxidation resistance, satisfactory malleability and formability, and excellent thermal and electrical conductivity. Especially during casting operations, high strength and machinability of Al-based alloys are of utmost concern. The quality and strength of casting products are affected by porosity generated due to the dissolution of gases and the effects of modifiers. Thus, unstable properties of Al alloys arising due to such influences should to be controlled by reinforcing suitable elements. Compared to other materials, brazing on Al requires higher control precision as the difference between the melting points of the base metal and the filler remain low even after the addition of melting point suppressants, such as Si. This necessitates the development of novel low-temperature Al-based filler metals. Moreover, the mechanical properties of Al-based alloys can be enhanced by introducing nanoparticles within them to reduce the thickness of Si-needles and IMCs (intermetallic compound) within the Al matrix, thereby refining the nanostructure.

Paillier Cryptosystem Based ChainNode for Secure Electronic Voting

Blockchain is a distributed and decentralized ledger of transactions that are linked together cryptographically leading to immutability and tamper-resistance, thereby ensuring the integrity of data. Due to the ability of blockchain to guarantee the integrity of data, it has found wide-range adoption in electronic voting (e-voting) systems in recent years, this is in a bid to prevent manipulation of votes. However, due to the distributed nature of the blockchain, opportunities arise for privacy intrusion of the data being secured. The translation of this privacy flaw in blockchain to e-voting systems is the possibility of violation of the privacy of the electorates. Consequently, in a bid to achieve integrity and privacy of votes in e-voting, this study presents the use of an open-source blockchain system, coupled with a privacy-oriented cryptosystem known as the Paillier cryptosystem, towards addressing the privacy concerns of the blockchain. The performance of the system was evaluated and a transaction throughput of 1424 tps was obtained for ten thousand simulated ballot transactions. Further evaluation was carried out on the system, by increasing the number of system transactions. This showed that the mining time of the blockchain increased by an average factor of 0.18 s for every thousand increases in the number of transactions. Also, the response time of the system to a range of user actions was evaluated over an increasing number of voters. Results obtained showed that the response time of the system for vote casting operations increased by an average of 0.33 min per thousand voters while for vote tallying there was an increase in response time by an average of 0.848 min per thousand voters. The scientific value of this study is the development of an integrity and privacy-preserving e-voting system consisting of an open-source nodechain coupled with a privacy-oriented cryptosystem known as the Paillier cryptosystem following the security requirements of e-voting systems. The proposed system addresses the issue of integrity in e-voting while still maintaining the privacy of the electorates.

Properties of Microconcrete Produced with Fly Ash and Ultrafine Silica

Abstract Microconcrete is an important subclass of regular concrete that lacks the coarse aggregate commonly found in standard concrete. This makes it a good candidate for certain casting operations, such as densely reinforced elements. Microconcrete also tends to have better workability and smoother flow in formwork elements than regular concrete. However, one of humanity’s current problems is air pollution caused by chemical, physical, or biological agents with harmful effects on the environment. Carbon dioxide (CO2) resulting from cement production is a major atmospheric pollutant. To align with sustainable development standards, the construction industry must seek alternative materials that are more environmentally friendly. This article presents a comparison of the properties of regular microconcrete and microconcrete with additives such as fly ash and ultrafine silica. This topic is important because environmental issues are becoming more pressing. The results show that using waste products as additives in microconcrete can provide a sustainable solution for reducing carbon dioxide emissions and environmental impact. Although lower strengths were obtained compared to traditional concrete, microconcrete with waste products can be used in various applications, such as the production of prefabricated construction elements or the rehabilitation of existing structures. Additionally, it can be used in the construction of paving stones, sidewalks, or industrial floors, contributing to reducing pollution and environmental impact.

Caster roll failure prevention – Prognosis & diagnosis through monitoring system of machine cooling water circuit

Rourkela Steel Plant has two slab casters having soft water circuit for machine cooling. Each caster segments comprises of solid forged steel rolls with water-cooling hole in guide roll. Failure of these rolls due to thermal fatigue restricts the efficiency of continuous casting operation. The main reason for roll breakage due to thermal fatigue is the reduced volume of water through the internal cooling hole and allowing rolls operating temperature to increase. The magnitude of thermal stress is influenced by the external and internal roll cooling efficiency since it controls the magnitude of ΔT. Impairment of internal cooling efficiency can lead to development of fire cracks of the bore surface and finally leading to roll failure. To prevent the caster roll failure due to thermal fatigue as a sequel to impairment of internal water cooling efficiency, the need was to install a system for real time measurement of water flow, pressure and temperature of inlet and outlet water through these segments. A system for real-time measurement of these parameters was installed in the caster segment of Steel Melting Shop- Rourkela Steel Plant for prognosis and diagnosis of the impairment of the internal cooling water circuit. Through the various dashboards, it was possible to monitoring the inlet – outlet water flow rate, pressure difference and differential temperature. Diagnosis of the causes of the rise in differential temperature was made possible through the water flow rate and pressure indications in the dash board. Through the monitoring system for machine cooling water circuit it was possible to reduce the caster roll failure due to thermal fatigue through proper diagnosis and prognosis. The monitoring systems for machine cooling water circuit has been effectively used for preventing the failure of caster rolls due to reduced thermal stresses and improve the machine availability.

Perda de temperatura em revestimentos odontológicos, após sua remoção do forno

The time elepsed between the removal from the furnace of a castin cylinder and the casting proper, depends on the knowledge and ability of the operator. The heat loss, after removal of a furnace temperature of 700ºC at different time intervals, was mensured in four dental casting investiments, using different volumes of investment, with or without the protection of a casting ring and with or without asbestos liner. The results, presented in the form of tables and graphs, tell us about the importance of this additional technical detail, in the dental casting operation. Temperature losses in the order of from 100º to 200ºC were verified, already two minutes after removal from the furnace.