Continuous Casting Equipment Research Articles

Comprehensive Evaluation Method for Cooling Effect on Process Thermal Dissipation Rate during Continuous Casting Mold

Cooling in the continuous casting mold is the essential process of the molten steel solidifying into a slab shell. The synergistic relationship of casting state, process operation, continuous casting equipment, and other factors is complex and has a significant influence on thermal transfer in the mold. Therefore, a concept of “process thermal dissipation rate” defined by mold system thermal input and output was proposed in this work. The thermal input of molten steel was calculated through the casting temperature, and the slab residual thermal at the outlet of the mold was calculated by the solidification heat transfer model. Consequently, the thermal dissipation rate was calculated to quantify the multi-factor cooperative relationship of mold. The industrial case reflected that the thermal dissipation rates of three stable castings were 12.5%, 14.3%, and 18.8%, respectively, and all of them were obviously abnormal in unsteady casting such as start casting, changing tundish, and end casting. The results above indicated that the thermal dissipation rate could characterize the mold cooling target under the cooperation of complex factors and provide a new method for the dynamic evaluation of the mold system cooling effect with different casting states. Accordingly, the correlation analysis between superheat, casting speed, cooling water flow, and thermal dissipation rate revealed the synergistic influence law of multi-operation on mold cooling effect, which provided a new idea for the precise control of multi-process collaboration in continuous casting.

Concept development, design and validation of a novel continuous casting equipment

PurposeThe purpose of this paper is to develop a concept and design to cast Al alloys/metal matrix composites (MMCs) by continuous casting process. The various steps involved in the evolution of the design have been reported and discussed in this study.Design/methodology/approachOn the basis of developed design concept, initial prototype design has been prepared in this study. The casting process's melt flow pattern was studied via computer simulation, and the resulting changes were implemented in the original design. The single-phase fluid flow pattern through bottom feeding technique is studied. The equipment was fabricated based on computer simulation and water modelling studies. Finally, validation was performed for the preparation of Al alloys/ MMCs after parameter optimisation. The results were observed in the optical metallography to confirm the alloying and Al MMC preparation.FindingsThe developed continuous casting process with bottom feeding technique for the addition of constituent particles shows more efficiency in comparison to the existing batch processes. The final manufactured setup demonstrates effective Al alloy/MMC production as the basis for final fabrication has been accomplished by both computer simulation and water model test. In addition, the microstructure exhibits homogeneous distribution, validating the reliability of the setup.Originality/valueIntegrating continuous casting with continuous reinforcement or master alloy addition is novel in this area. The constraints that batch production had that have been rectified will also lower the contemporary cost of production.

Abnormal structure and properties of copper–silver bar billet by cold casting

Abstract Copper alloy rod billet with 20% silver was prepared using homemade three-chamber vacuum cold-type vertical continuous casting equipment. The variation rules of the microhardness, eutectic ratio, and size and distribution of silver particles precipitated in the primary α-Cu phase at the end of the continuous casting alloy rod blanks were studied using a microhardness tester and scanning electron microscope. The obtained results show that when the cold-type vertical continuous casting speed is 120 mm·min−1, there is obvious reverse segregation of solute element near the end of the prepared ∅7.8 mm copper–silver alloy rod blank. From the end of the continuous casting alloy rod blank to 5 mm from the end, the Cu–Ag eutectic structure in the copper–silver alloy increases from 13.4 to 15.9%, and the size of Ag particles precipitated in the primary α-Cu phase increases from 100 to 350 nm. The microhardness increases from 56 HV0.05 to 85 HV0.05. When the distance from the end exceeds 5 mm, the microstructure and properties of the continuous casting alloy rod blank are basically stable.

The Application of Computational Thermodynamics in the Understanding and Control of Clogging and Scum in Continuous Casting of Steel

Non-metallic inclusions are present in small volume fractions in steel products. A significant portion of them is associated to the deoxidation process. The type and form of inclusions is, in general, directly connected to the deoxidation practice and to eventual reoxidation during processing. Besides influencing the steel properties, non-metallic inclusions can have an important effect on their processability. In this work, we review the processability questions associated with inclusions in the continuous casting of steel, with emphasis on long products. When solid inclusions are present during the casting of steel they may agglomerate and clog the valves used in the continuous casting equipment, limiting the number of sequential heats that can be casted and reducing casting speeds. Additionally, in some conditions, solid non-metallic inclusions may agglomerate and form surface defects in the continuous casting products, sometimes referred to as scum. As productivity and quality are essential to the profitability of steelmaking, avoiding these conditions is of paramount importance. Thus, we review the main thermodynamic conditions that may lead to the clogging of continuous casting valves, and discuss, from the thermodynamic point of view, the measures that can be taken to avoid the occurrence of these various conditions. Furthermore, we discuss the conditions that might cause to the formation of scum and the thermodynamics of its formation and elimination. It is concluded that the analysis of steelmaking conditions via computational thermodynamics can have an important role in avoiding problems in continuous casting and helping ensure productivity and quality in the process.

Heuristic modeling of casting processes under the conditions uncertainty

In the first part of this paper will be described an analysis of control problems and technical lifetime modeling of continuous casting device crystallizers. A full exploitation of continuous casting equipment (CCE) advantages can only be achieved through a control system that minimizes all undesirable effects on the technological process. Some of the undesirable effects influencing the CCE process effectiveness are the failures and service interruptions. This problem was solved by connection of dependability theory and artificial neural networks.The second part of the article refers to a model in linguistic form used to identify the type of defects present in the tested casting. This model, having the form of an attribute table, has been based on the concepts taken from the theory of rough sets and fuzzy logic. A methodology for construction of a heuristic model of linguistic knowledge was presented along with an example of its implementation based on the use of distributed sources of knowledge.

A Cloud-Based Framework for Lean Maintenance, Repair, and Overhaul of Complex Equipment

Large, complex, expensive, and long-lived equipment often operate in harsh environments, which leads to the requirements of lifecycle maintenance, repair, and overhaul (MRO). To support the continuous improvement of productivity and to reduce the cost of MRO, this paper developed a cloud-based framework for lean MRO of the equipment with the aforementioned characteristics. A concept and a model of lean MRO are proposed. Taking advantage of cloud-based design and manufacturing (CBDM) into account, an architectural framework of cloud-based MRO is proposed. A case of a lean MRO for continuous casting equipment demonstrates that the proposed cloud-based framework can achieve the goal of lean MRO of complex equipment.

The Performance of Tungsten Carbide and High Speed Steel When Drilling Nickel–Copper

Machining of components made of materials with dissimilar properties demands the judicious selection of tooling and cutting conditions. The aim of this work is to investigate the behavior of tools with different compositions and geometries when drilling hybrid metallic (Ni–Cu) components used in continuous casting equipment. Thrust force and hole accuracy were investigated under various machining conditions and the results indicated that drill type and feed rate are the principal factors affecting thrust force. Moreover, hole diameter deviation was affected by drill type only and the influence of cutting speed was found to be negligible within the cutting range tested.

New continuous-casting equipment

New equipment for plasma heating of steel in the intermediate ladle is discussed. Experiments have been conducted on continuous-casting machine 4 at OAO Magnitogorskii Metallurgicheskii Kombinat, in collaboration with Bardin Central Research Institute of Ferrous Metallurgy, OOO AGNI-K, and other organizations.

Mechanical and Memory Properties of CuAlNi by Directional Solidification

Abstract Cu-Al-Ni shape memory alloy was fabricated under directional solidification in heated mold continuous casting equipment. The results show that it has distinct textures. Due to these strengthened textures, it has excellent mechanism, fatigue and memory performances. The Ø 1.5 mm wire has a tensile strength of 910 MPa, elongation of 18.76%. Under 4% strain, the repeat tensile fatigue was up to 38560 circles and the recovery rate is 100%.

The use of artificial intelligence technique for the optimisation of process parameters used in the continuous casting of steel

The productivity and quality of a continuous caster depend mainly on process parameters, i.e. casting speed, casting temperature, steel composition and cleanliness of the melt, water flow rates in the different cooling zones, etc. This work presents the development of an algorithm, which incorporates heuristic search techniques for direct application in metallurgical industries, particularly those using continuous casting process for the production of steel billets and slabs. This is done to determine the casting objectives of maximum casting rate as a function of casting constraints. These constraints are evaluated with the aid of a heat transfer and solidification model based on the finite difference technique, which has been developed and integrated with a genetic algorithm. The essential parts of continuous casting equipment, which must be subjected to monitoring, as well as a methodology of mathematical model and physical settlements in each cooling region, are presented. The efficiency of the intelligent system is assured by the optimisation of the continuous casting operation by maximum casting rate and defect-free products. This approach is applied to the real dimension of a steel continuous caster, in real conditions of operation, demonstrating that good results can be attained by using heuristic search, such as: smaller temperature gradients between sprays zones, reduction in water consumption and an increase in casting speed.

New high-temperature copper alloys

New high-strength, high-temperature Cu-Ni-Si alloys have been developed using additions of Cr, Zr, and/or Ti. These new alloys remain as precipitation hardenable as the base alloy, but the main strengthening phase may be different than Ni2Si (e.g., Cr2Ti). Substantial increases in mechanical strength were observed at both room and high temperature (773 K) when additions of Cr+Zr+Ti and Cr+Zr were made. Industrial testing of these alloys indicated a sevenfold increase in the lifetime of lateral blocks in continuous casting equipment of copper alloys.

Three-dimensional simulation of the edge rolling process by the explicit finite-element method

Due to a recent emphasis on resource and energy saving technologies in the steel industry, steel slabs are now produced from continuously cast stock. Efficient operation of the continuous casting equipment limits the number of mould sizes, and width control is carried out by vertical rolling (edge rolling). The value of a finite element analysis based on an explicit dynamic formulation with geometric and material non-linearity for simulating edge rolling and subsequent flat rolling to investigate optimum rolling procedure to minimize crop losses is demonstrated. Edging with flat rolls, calibre (grooved) rolls and flat rolls with roll-gap control were compared and the result of subsequent flat rolling was investigated. It was concluded that the explicit dynamic finite element method with appropriate damping can be a useful tool for the design of optimum rolling schedules. Although necking of the ends of slabs increased slightly when calibre rolls were used for edging, a more favourable dog- bone shape was produced so that the result was achievement of better control of slab shape after flat re-rolling.