This paper presents a numerical model for the horizontal continuous casting of cast iron (HCCCI). A computational three-dimensional (3D) steady-state, coupled with fluid flow and heat transfer simulation model was developed and validated against experimental results to study the shell thickness and solidification of ductile cast iron. The study introduces the influence of an air gap at the melt-mould interface, which has long been known to have a detrimental effect on the efficiency of the process. The effect of the length and thickness of the melt-mould air gaps (also referred to as top air gaps) on solidification and remelting of the solid strand is studied. Parametric studies on top air gaps suggested a substantial effect on the solid and eutectic area at the top-outlet end of the die when the length of air gas was varied. This study serves to create a foundational and working model with the overall objective of process optimisation and analyzing the effect of operating process input parameters on the shell thickness of the strand.
The article presents tests on a new lead-free bronze CuSn4Zn2PS, intended for fittings for contact with drinking water, in which the addition of lead was replaced with sulphur. The subject of the experimental work was the production of semi-finished products from this alloy based on the charge coming entirely from waste generated after machining. A specialized pilot line was used for the tests, and after cleaning, the waste was melted and then were continuously cast in the form of rods and hollow rods. The cleaning efficiency was assessed, and the manufactured semi-finished products were subjected to tests, including the assessment of the chemical and mechanical homogeneity and the structure of the test batch of the semi-finished casting products in terms of the possibility of manufacturing products meeting the requirements of technical specifications. The obtained results, both in terms of a stable chemical composition, homogeneous and reproducible mechanical properties, fully compliant with the specifications for fittings bronzes (CC499K), as well as the lack of faults of the obtained semi-finished products, despite a very large share of waste material, indicate the possibility of using the tested recycling method for the production of semi-products of sulphur bronze, which is an alloy that is relatively difficult to manufacture.
The paper presents the results of research aimed at developing assumptions for the preparation of a charge in the form of fine scrap copper alloys (chips/shells) guaranteeing effective removal of impurities and obtaining a metal bath of the required metallurgical quality. The tests were conducted for tin-zinc-lead bronze of the CC499K grade. As part of the work, the characteristics of this type of waste available on the market were made in terms of quality and the possibility of their use for the production of both alloys and finished products, taking into account the elimination of harmful impurities that may ultimately affect the production process adversely. The subject of the work was the selection of appropriate waste cleaning methods in the form of an oily shell in the CC499K (CuZn5Sn5Pb2) grade and its drying in terms of increasing the use of impure waste from machining as scrap for direct melting. The waste was assessed in relation to individual parameters. The research was carried out on 3 groups of waste, with varying degrees of moisture.
A tundish is a device from which liquid steel is pour into a mold. Therefore tundish hydrodynamic conditions have a significant impact on solidification during continuous steel casting (CSC) process. Modification of ladle shroud workspace, allows for the modification of liquid steel movement in the tundish. In the following work, numerical simulations were performed which allowed the impact of the modification of the ladle shroud workspace on the liquid steel flow structure in a one-strand tundish to be determined. In order to assess the impact of the modification of the ladle shroud on the behavior of the liquid steel in the tundish, simulations were performed, on the basis of which the percentage share of stagnant, ideal mixing and plug flow zones were determined. In addition, the mixing parameters were determined, allowing the estimation of casting duration during sequential casting. The flow fields of liquid steel for each modification of the ladle shroud were performed. The average velocity of liquid steel flowing through the tundish, the Reynolds number and turbulent intensity were also described. The obtained results showed, among others, that the application of three cylinders with a diameter of 0.041 m into the ladle shroud with a diameter of 0.11 m increases the share of active flow in the tundish in relation to the tundish with Conventional Ladle Shroud. At the same time, applying a ladle shroud with a diameter of 0.11 m during casting is the most favorable in relation to the hydrodynamics of the tundish.
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The article presents an overview of currently used coatings for the surface protection of die casting moulds and continuous casting moulds against liquid Al. The analysis of literature data indicates that coatings based on CrN, TiN nitrides, carbonitrides and carbides (TiC), as well as multilayer coatings are most commonly used. Various PVD and CVD processes are used for their production. Coatings produced by thermal spraying processes are also of great importance. The results described in the literature are divergent, which hinders the selection of a protective coating for new applications and determines the performance of experimental studies.
PL
W artykule przedstawiono przegląd obecnie stosowanych powłok do ochrony powierzchni kokili do odlewania ciśnieniowego oraz krystalizatorów do ciągłego odlewania przed oddziaływaniem ciekłego aluminium. Analiza danych literaturowych wskazuje, że najczęściej stosowane są powłoki oparte na azotkach CrN, TiN, węglikoazotkach i węglikach (TiC) oraz wielowarstwowe. Do ich wytwarzania stosuje się różne procesy PVD i CVD. Duże znaczenie mają też powłoki wytwarzane w procesach natryskiwania cieplnego. Wyniki opisane w literaturze są rozbieżne co utrudnia dobór powłoki ochronnej dla nowych zastosowań i determinuje przeprowadzenie badań eksperymentalnych.
W artykule omówiono zastosowaną w praktyce metodologię dynamicznego wyznaczania przegrzania stali oraz jej wpływ na zwiększenie precyzji sterowania procesem ciągłego odlewania stali na maszynie COS. Przeprowadzono również analizę porównawczą metody alternatywnej kontrolnego pomiaru temperatury stali w kadzi pośredniej z wykorzystaniem przykładowych opomiarowanych sekwencji. Wskazano na potencjalne zagrożenia wynikające z bazowania podczas sekwencji ciągłego odlewania na pomiarze kontrolnym w porównaniu do pomiaru ciągłego oraz różnice występujące pomiędzy temperaturą likwidusu liczoną wg różnych modeli matematycznych i mierzoną czujnikiem zanurzeniowym.
EN
This article briefly reviews dynamic superheat of steel determination in practice and presents the outcomes for more accurate continuous casting process control. The competitive methods have been evaluated using casting sequences with both continuous and dip steel temperature measurement. The potential threats of operating a caster based on dip temperature only in comparison with continuous measurement have been indicated along with the differences in liquidus temperatures determined by various mathematical models and the physically measured value.
The mold temperature of the downward continuous unidirectional solidification (CUS) cannot be controlled higher than the liquidus of alloys to be cast. Therefore, the continuous casting speed becomes the main parameter for controlling the growth of columnar crystal structure of the alloy. In this paper, the tin bronze alloy was prepared by the downward CUS process. The microstructure evolution of the CUS tin bronze alloy at different continuous casting speeds was analysed. In order to further explain the columnar crystal evolution, a relation between the growth rate of columnar crystal and the continuous casting speed during the CUS process was built. The results show that the CUS tin bronze alloy mainly consists of columnar crystals and equiaxed crystals when the casting speed is low. As the continuous casting speed increases, the equiaxed crystals begin to disappear. The diameter of the columnar crystal increases with the continuous casting speed increasing and the number of columnar crystal decreases. The growth rate of columnar crystal increases with increasing of the continuous casting speed during CUS tin bronze alloy process.
Z uwagi na wysokie własności użytkowe, a przede wszystkim wysoką podatność na obróbkę skrawaniem, elementy wykonane ze stopu aluminium serii 2XXX znajdują szerokie zastosowanie w wielu gałęziach współczesnego przemysłu. Tradycyjna technologia ich wytwarzania bazuje na procesie odlewania wielkogabarytowych wlewków oraz następującego po nim procesie wyciskania. W artykule zaprezentowano wyniki badań nad alternatywną metodą ich wytwarzania, a więc procesem ciągłego odlewania profili okrągłych o średnicy 40 mm. W dalszej części przedstawiono analizę ich własności mechanicznych, elektrycznych oraz składu chemicznego przeprowadzonych dla odlewów w gat. EN AW-2007.
EN
Elements manufactured from aluminum alloys series 2XXX are widely used in many branches of modern industry due to their high functional properties and high susceptibility to machining. Traditionally the production of such elements is based on the casting process of large-sized ingots and their subsequent extrusion process. This article presents the research results of the alternative method of their manufacturing which is the process of continuous casting of round profiles with a diameter of 40mm. The article includes the analysis of mechanical, electrical and chemical properties of the EN AW-2007 alloy castings.
There has been a growing interest in the peritectic due to increasing productivity, quality, and alloy development. Differential scanning calorimetry (DSC) has traditionally been used to study steel solidification but suffers significant limitations when measuring the solidus and peritectic. This work covers a new thermal analysis system that can characterize the peritectic reaction. Heats of AISI/SAE 1030 and 4130 steel were poured to provide some benchmarking of this new technique. The peritectic was detected and the reaction temperature measured. Measurements agree reasonably well with reference information. A review of the literature and thermodynamic calculations did find some disagreement on the exact temperatures for the peritectic and solidus. Some of this difference appears to be related to the experimental techniques employed. It was determined that the system developed accurately indicates these reaction temperatures. The system provides a unique method for examining steel solidification that can be employed on the melt deck.
The paper consists the problem of developing a scientific toolkit allowing to predict the thermal state of the ingot during its formation in all elements of the casting and rolling complex, between the crystallizer of the continuous casting machine and exit from the furnace. As the toolkit for the decision making task the predictive mathematical model of the ingot temperature field is proposed. Displacement between the various elements of the CRC is accounted for by changing the boundary conditions. Mass-average enthalpy is proposed as a characteristic of ingot cross-section temperature state. The next methods of solving a number of important problems with the use of medium mass enthalpy are developed: determination of the necessary heat capacity of ingots after the continuous casting machine for direct rolling without heating; determination of the rational time of alignment of the temperature field of ingots having sufficient heat capacity for rolling after casting; determination of the total amount of heat (heat capacity) required to supply the metal for heating ingots that have insufficient amount of internal heat.
In this paper results of microstructural observations for series of CuZn39Pb2 alloys produced from qualified scraps are presented. The individual alloy melts were differentiated in terms of thermal parameters of continuous casting as well as refining methods and modifications. Structural observations performed by SEM and TEM revealed formation of different types of intermetallic phases including “hard particles”. EDS results show that “hard particles” are enrich in silicon, phosphorus, iron, chromium and nickel elements. Additionally, formation of Al-Fe-Si and Al-Cr in alloy melts was observed as well. It was found that quantity and morphology of intermetallic phases strongly depends upon the chemical composition of raw materials, process parameters, modifiers and refining procedure applied during casting. It was observed that refining process results in very effective refinement of intermetallic phases, whereas modifiers, particularly carbon-based, results in formation of large particles in the microstructure.
Odlewanie ciągłe jest dominującą technologią produkcji półwyrobów hutniczych. Zwiększenie wydajności przy zachowaniu odpowiedniej jakości i ekonomiczności procesu jest głównym celem optymalizacji procesów odlewania ciągłego we wszystkich jego odmianach. MAGMA CC, samodzielne oprogramowanie symulacyjne firmy MAGMA, umożliwia realizację tego celu poprzez wykorzystanie wirtualnych eksperymentów oraz automatycznej optymalizacji.
EN
Continuous casting is the preferred process for manufacturing semi-finished products. Increasing productivity without decreasing quality and efficiency is the main objective for all continuous casting processes. MAGMA CC, stand-alone simulation software from MAGMA, enables fulfilling this objective using Design of Experiments and autonomous optimization.
W pracy przedstawiono analizę procesu ciągłego odlewania półwyrobów z brązu cynowo-cynkowo-ołowiowego przeznaczonego na obrabiane mechanicznie elementy armatury. Przedstawiono wyniki badań zmierzające do określenia przyczyn powstawania wad podczas procesu ciągłego odlewania. W tym celu wykonano analizę procesu ciągłego odlewania, rodzaju, postaci stosowanych materiałów wsadowych i pomocniczych oraz powstających wad. Na podstawie otrzymanych wyników badań, w celu udoskonalenia procesu, przedstawiono zakres wprowadzonych zmian i ich wpływ na jakość wytwarzanych wyrobów.
EN
The paper presents an analysis of the continuous casting process of semi-finished product made of tin-zinc-lead bronze, designed to mechanically machined elements of fittings. The results of tests to determine the causes of defects during the continuous casting process are presented. For this purpose, an analysis of the continuous casting process, as well as the type, the form of batch and auxiliary materials, and the appeared defects were made. Based on the results of the research, in order to improve the process, the scope of introduced changes and their impact on the quality of manufactured products are presented.
The paper presents the research results of the influence of the precipitation hardening on hardness and microstructure of selected Al-Si and Al-Cu alloys obtained as ϕ30 mm ingots in a horizontal continuous casting process. The ingots were heat treated in process of precipitation hardening i.e. supersaturation with subsequent accelerated or natural ageing. Moreover in the range of the study it has been carried out investigations of chemical constitution, microscopic metallographic with use of scanning electron microscope with EDS analysis system, and hardness measurements using the Brinell method. On basis of obtained results it has been concluded that the chemical constitution of the investigated alloys enables to classify them into Al alloys for the plastic deformation as EN AW-AlSi2Mn (alternatively cast alloy EN AC-AlSi2MgTi) and as EN AW-AlCu4MgSi (alternatively cast alloy EN AC-AlCu4MgTi) grades. Moreover in result of applied precipitation hardening has resulted in the precipitation from a supersaturated solid solution of dispersive particles of secondary phases rich in alloying element i.e. Si and Cu respectively. In consequence it has been obtained increase in hardness in case of AlSi2Mn alloy by approximately 30% and in case of AlCu4MgSi alloy by approximately 20% in comparison to the as-cast state of continuous ingots.
The article presents results of research on the influence of variable parameters of horizontal continuous casting on the structure of AlCu4MgSi (EN AW-2017A) alloy ingots. The special character of the process allows for a continuous change of some of its parameters, namely, of the casting speed and of the rate of the cooling fluid flow thorough the crystallizer. These parameters have a significant impact on the crystallization process of the liquid metal. Depending on the cooling rate, intensity of the convection inside the solidifying alloy, and its chemical composition, there may arise some differences in the structure of the cast. In this study, ingots obtained at different casting speeds have been analyzed. The research methodology, based on light microscopy and electron microscopy (SEM), as well as energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), allowed for a thorough examination of the structure of the studied materials. The results were shown that an increase in the ingot casting speed leads to an increase in the average grain surface area.
This article discusses issues related to continuous casting of brass. The tested material was CuZn39Pb2 brass with the use of continuous casting and different parameters of the process. The position consists of a melting furnace with a graphite refining pot of about 4000 cm3 chuting capacity, a graphite crystallizer of 9,5 mm nominal diameter, a primary and secondary cooling system and an extracting system as well. The analysis was carried out in terms of technological parameters of the process and type of charge. Highlighted: feedrate ingot, number of stops, and technological temperatures. The surface quality of the obtained ingots and the structure were analyzed. The most favorable conditions were indicated and technological recommendations indicated. They have been distinguished for ingots for plasticity and other technologies. Favorable casting conditions are low feed and low temperature. Due to the presence of impurities coming from the charge it is disadvantageous to have Ni greater than 0.053% by mass, and Fe more than 0.075% by mass. It is recommended to maintain a high zinc content in the melt which is associated with non-overheating of the metal during casting and earlier melting.
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Artykuł prezentuje 4 wdrożone zautomatyzowane systemy technologiczne dotyczące termicznej obróbki i przetwarzania metali z zastosowaniem nagrzewania indukcyjnego, w których istotną rolę odgrywa precyzyjne sterowanie licznymi parametrami procesu.
EN
The paper presents four implemented automated systems for thermal machining and processing of metals using induction heating, where precise control of numerous process parameters plays an important role.
W artykule przedstawiono wyniki badań nad własnościami mechanicznymi i elektrycznymi prętów Cu OFC uzyskanych w innowacyjnej demonstracyjnej linii do ciągłego topienia i odlewania (TF-AGH). W procesie ich otrzymywania wykorzystano jako materiał wsadowy granulat miedzi pochodzący z odpadów pokablowych a nie, jak w tradycyjnych rozwiązaniach, katody. W ramach prowadzonych prac uzyskane pręty zostały poddane procesowi ciągnienia na druty, następnie przebadane pod kątem kształtowania się ich własności mechanicznych i elektrycznychw funkcji odkształcenia rzeczywistego, na podstawie czego opracowano m.in. krzywe umocnienia. Prace nad zintegrowaną, demonstracyjną technologią ciągłego topienia i odlewania z wykorzystaniem wsadu z granulatów pokablowych pozwoliły na otrzymywanie materiału o wysokiej czystości chemicznej i zadowalającym poziomie własności elektrycznych i mechanicznych, stanowiący pełnowartościowy półprodukt do wytwarzania wyrobów na cele elektryczne i elektroenergetyczne.
EN
In this paper, research results on the mechanical and electrical properties of Cu OFC rods obtained in the demonstration installation for continuous melting and casting (TF-AGH) are presented. The obtaining process included as input material copper granules comes from waste cable, and not, as in traditional solutions cathode. As part of works, obtained rods were subjected to drawing process on wires and tested for the formation of their mechanical, electrical and plastic properties as a function of true strain, on this basis developed i.a. work hardening curves. Work on the integrated demonstration technology of continuous melting and casting using a charge of waste cable granules allowed to receive a material with high purity and acceptable electrical and mechanical properties, which is a semi-finished product of standard value to manufacture of products for electric purposes.
The Structural Peclet Number has been estimated experimentally by analyzing the morphology of the continuously cast brass ingots. It allowed to adapt a proper development of the Ivantsov’s series in order to formulate the Growth Law for the columnar structure formation in the brass ingots solidified in stationary condition. Simultaneously, the Thermal Peclet Number together with the Biot, Stefan, and Fourier Numbers is used in the model describing the heat transfer connected with the so-called contact layer (air gap between an ingot and crystallizer). It lead to define the shape and position of the s/l interface in the brass ingot subjected to the vertical continuous displacement within the crystallizer (in gravity). Particularly, a comparison of the shape of the simulated s/l interface at the axis of the continuously cast brass ingot with the real shape revealed at the ingot axis is delivered. Structural zones in the continuously cast brass ingot are revealed: FC – fine columnar grains, C – columnar grains, E – equiaxed grains, SC – single crystal situated axially.
The paper presents the research results of horizontal continuous casting of ingots of aluminium alloy containing 2% wt. silicon (AlSi2). Together with the casting velocity (velocity of ingot movement) we considered the influence of electromagnetic stirring in the area of the continuous casting mould on refinement of the ingot’s primary structure and their selected mechanical properties, i.e. tensile strength, yield strength, hardness and elongation. The effect of primary structure refinement and mechanical properties obtained by electromagnetic stirring was compared with refinement obtained by using traditional inoculation, which consists in introducing additives, i.e. Ti, B and Sr, to the metal bath. On the basis of the obtained results we confirmed that inoculation done by electromagnetic stirring in the range of the continuous casting mould guarantees improved mechanical properties and also decreases the negative influence of casting velocity, thus increasing the structure of AlSi2 continuous ingots.
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