Slide Gate Research Articles

The application of the state-of-the-art turbulence models in the OpenFOAM CFD codes and the validation for different flow control cases in the continuous casting process

Computational fluid dynamics (CFD) is an established approach to study flow behaviour. Despite advances in mathematical numerical modelling in recent decades, accurately predicting the turbulent flow behaviour of steel using CFD remains a challenge. In the continuous casting process, two main flow control systems are employed to transfer liquid steel from the tundish to the mould, namely stopper control and slide gate control. In additional to these two main flow control systems, the casting nozzle geometries, casting rate, and casting mould dimensions vary considerably, and this complexity makes it difficult to precisely simulate turbulent flow in the casting channel. In this paper, examples are presented showing how different turbulence models influence the simulation results, using the latest version of the open source CFD simulation software OpenFOAM. Prior to the CFD modelling, RHI Magnesita's water modelling facilities in Leoben (Austria) were used to validate the state-of-the-art turbulence models selected for a particular casting nozzle geometry and flow control system.

Enhancing the thermal shock and corrosion resistance of low‐carbon Al2O3–C refractories: The role of h‐BN composite powder

AbstractDeveloping low‐carbon and high‐performance Al2O3–C refractories is vital for extending the service life of slide gate plate refractories and reducing carbon emissions. In this study, hexagonal boron nitride (h‐BN) composite powder was prepared using the magnesiothermic reduction combustion synthesis route and introduced into low‐carbon Al2O3–C refractories. The phases composition, microstructure, mechanical properties, thermal shock, and slag corrosion resistance of low‐carbon Al2O3–C refractories were investigated. The results show that the thermal shock and slag corrosion resistance of low‐carbon Al2O3–C refractories enhanced by adding h‐BN composite powder. Due to the introduced h‐BN, consequent in situ formed spinel and AlN whiskers, the crack propagation in the refractories was deflected, branched forming more fine cracks, then the thermal shock resistance was enhanced. In addition to the chemical inertness of h‐BN, in situ formed spinel and AlN whiskers, the consequent decrease in pore size plays an important role in enhancing the slag corrosion resistance of the refractories. The h‐BN composite powder synthesized via the combustion synthesis in this study demonstrated potential application in high‐performance Al2O3–C slide gate plates used in continuous casting technology.

Failure analysis of Al2O3–C–SiO2 slide gate plates during continuous casting based on numerical simulation

The thermo-mechanical and failure behavior of the burning-free Al2O3 –C–SiO2 slide gate plate materials during the steel casting process are investigated. Firstly, the instantaneous coefficient of thermal expansion and the Young's modulus of the slide gate plate materials with different component contents at high temperature are measured. Secondly, a material constitutive model and a concrete damage plasticity mode are established based on the experiments, and adopted to simulate the failure behavior of the burning-free Al2O3–C–SiO2 slide gate plate during casting based on Finite Element Method (FEM) analysis. Results show that temperature gradient in the slide gate plate near the casting hole increased significantly and had a significant influence on cracking. The area near the casting hole of the slide gate plate is under tensile stress conditions, and then changes towards compressive stress conditions. Under those severe thermal stress conditions, crack formation is evaluated and an optimized composite structure of the slide gate plate combining advantages of reducing the risk of cracking and extending the service life is proposed. Moreover, the thermal shock test further verified that the microcrack extension was significantly alleviated due to the SiC distributed in whisker form and formed an interlocking structure in material. This work provides a reliable theoretical and experimental basis for the design and optimization of high performance Al2O3–C–SiO2 slide gate plates.

APPLICATION OF HVOF TECHNOLOGY FOR WC-BASED WEAR-RESISTANT COATINGS – AN OVERVIEW

The article presents the main problems of wear and service life of slide gate valves for trunk pipeline transport of oil and gas industry. One of the possible ways to solve these problems is the application of a thin layer of wear-resistant and corrosion-resistant coatings. Due to the ever-increasing cost of materials, as well as the increased requirements for materials, coating methods have recently become increasingly important. Among the gas-thermal coating methods, the High Velocity Oxygen-Fuel Spray (HVOF) technology is a new and rapidly developing technology that produces high density coatings with porosity less than 1%, with improved hardness and adhesion as well as improved erosion, corrosion and wear resistance properties. This overview article provides a comparative review of the characteristics of carbide coatings produced using different spraying technologies.

Physical modeling of slag carryover in the last stage of ladle teeming during continuous casting with dynamic change of slide gate opening

To investigate slag carryover in the last stage of ladle teeming during continuous casting, a water model system was established. The nozzle flow rate of model ladle was controlled by slide gate, which was automatically governed by a control module. The prototype teeming process can be accurately modelled through the system. However, under the condition that the slide gate is fully opened, the teeming process in water model has a great deviation with the actual. The vortex critical height in the mode of dynamic changing of slide gate is obviously less than that under the condition of 100% opening. Furthermore, under the dynamic changing mode, effects of operating parameters on vortex formation and slag carryover have been investigated. The vortex critical height decreases as the residence time before teeming increases. The effect of initial water level on critical height of vortex is little. As the flow rate increases, the critical height of vortex increases significantly. The variation of vortex diameter experiences developing stage and matured stage. When oil is added into model ladle, an important change is that the critical height of vortex decreases. By contrast, the vortex diameter obviously increases. The vortex critical height decreases while oil is added into ladle, but it increases as the oil layer thickness increases.

Experimental investigation of turbulent flow in a rectangular bonneted slide gate and eliminating random fluctuating loads

Bonneted slide gates are widely used in dam bottom outlets for flow regulation. High kinetic energy flow generates turbulence, which induces vibrations in bonneted slide gates under partially open conditions. Significant vibrations can indicate problems and cause damage or expedited deterioration of the gate if left unchecked. This experimental study focuses on two aspects: turbulent flow formation due to rectangular bonneted slide gates and elimination of random fluctuating loads on the gate using a turbulence inhibitor. Five reservoir heads were combined with nine gate openings (10%–90%) to produce 45 different discharges of 12–182 l/s. The different types of the gate flow create different turbulence and random loads based on the water–air mixture and the kinetic energy of the flow. Flow analysis indicates considerable random static pressure fluctuations under the slide gate. The results show the formation of swirling secondary flows in the gate's side guide slots, and their movement and collision with the gate are the leading cause of the turbulent multiphase flow and random fluctuations in static pressure. Also, the use of turbulence inhibitors on the gate can prevent the formation of secondary flows, which results in a 98.92% reduction in the amplitude of random static pressure fluctuations and the elimination of the random fluctuating loads on the slide gate. After removing the swirling secondary flows, a stable air boundary layer was formed under the gate. Finally, the gate flow changed from a turbulent two-phase flow to a steady single-phase jet of water.

Development of an automated sand supply system for places of technical inspection of locomotives

To increase labor productivity is one of the most important tasks of the branch strategic document of JSC "Russian Railways". The article describes the existing system of sand supply to the locomotive at the places of technical inspection of locomotives (PTIL), its shortcomings are revealed. At present, this system has been outdated and it does not meet the requirements of the modern logistics and the organization of railway operation. To solve this problem, an automated system of sand supply to the locomotive based on a rotary level gauge and a slide gate with a pneumatic drive has been developed, which will eliminate the disadvantages of the typical system, which will increase labor productivity.

Influencing Factors and Improving Measures about Automatically Opening of Ladle Sliding Gate Using Drainage Sand

Influencing Factors and Improving Measures about Automatically Opening of Ladle Sliding Gate Using Drainage Sand

SUBSTANTIATION OF ENERGY-POWER PARAMETERS OF THE STEEL LADLE SLIDE GATE CATAPULT

The theoretical and experimental studies were performed in the design and energy-power parameters of the catapult, which is part of the steel ladle slide gate and ensures the destruction of the crust, which often forms in the surface layer of the loose starting mixture at the inlet of the outlet channel and prevents the beginning of the free outflow of liquid metal when the ladle tundish is first opened. A method was proposed for calculating the dimensions of flat elastic elements of a catapult, taking into account the dimensions of slide gates installed on the steel casting ladles with a capacity of 100–300 tons, as well as the strength of the resulting crust. The obtained calculated dependences are based on the law of conservation of energy of the studied catapult system. It is shown that its use would eliminate the need to use oxygen for burning the solid bulkhead and thereby eliminate the intense destruction of the working walls of the steel outlet channel, contamination of the cast metal with exogenous inclusions and violation of the required velocity mode of its flow from the ladle. Compared with known foreign analogues, the proposed catapult favourably differs in its simple design, low cost, low operating costs and reusable application. This is achieved by moving its power unit out of the steel outlet channel of the ladle gate

Расчетно-теоретическое исследование режимов течения рабочей среды в шиберной задвижке для технологических линий нефтегазодобывающей промышленности

Slide gate valves are widely used as shut-off and control valves in technological lines of the oil and gas industry. The most important tasks that arise when designing a gate valve include the calculation of the hydraulic characteristics of the working medium flow and the determination of throughput. The article presents an overview of the main methods for calculating the throughput of pipeline fittings, indicates their advantages and drawbacks. It proposes a method for determining the throughput and calculating the hydraulic characteristics of the working medium flow of a high-pressure slide gate valve based on a computational-theoretical study using a modern complex of engineering analysis. A mathematical model of the working medium flow was developed and a numerical calculation performed. The correctness of the operation of the mathematical model was confirmed by comparing the data of computational-theoretical and experimental research. Based on the results of calculations and assessment of their correspondence to the real flow process in the physical prototype of the slide gate valve, conclusions were drawn about the applicability of the mathematical model.

Design and Implementation of a Digital Sliding Gate Using RFID Technology

Security of human life and property is one of the paramount challenges facing any corporate organization or nation. Security systems are necessary everywhere especially in residential buildings, industrial area and public offices. The need for automatic sliding gates has been on the increase in recent times because it does not require manual operation. The digital sliding gating system described in this work uses the Radio Frequency Identification (RFID) technology for access control. The RFID module, which is the sensing unit of the system, is interfaced with the processing unit (Atmega8a microcontroller) for controlling the actuating unit (sg90 servo motor). The sliding gate opens partially when the valid card for human access is brought closer to the reader, it opens fully when the valid card for vehicle access is brought closer to the reader while an invalid card brought closer to the reader activates the buzzer. The time taken for the reader to read the tag is 3 seconds for both human and vehicle access while the waiting period between the opening and closing of the gate are 10 seconds and 21 seconds for human and vehicle access respectively. These operations are made possible by the programmable microcontroller used and the pivot joint mechanism for the fast opening and closing of the gate. The developed system was tested and it performed as designed.Keywords— Microcontroller, Pivot joint, Radio Frequency Identification, Sliding gate, Tag.

Effect of silica concentration on degree of sintering of chromite-silica ladle well filler sand based on South African raw materials

During steelmaking, one important factor for production efficiency is the free opening of the ladle nozzle during continuous casting. Free opening occurs when the well filler sand and the steel flow freely when the slide gate is opened. Well filler sands are used for the slide gate of a ladle to separate the slide gate refractory and the molten steel. The well filler sand is partially sintered by the heat of the molten metal, which can result in the ladle nozzle failing to open if the sand is not sintered to an appropriate extent. It is therefore of great importance that the sintering behaviour of well filler sand is understood. We studied the effect of the well filler sand chemistry on its sintering properties. Samples of well filler sand with various chemical compositions were sintered in a high-temperature chamber furnace. Quantitative X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES), and wavelength dispersive spectrometry (WDS) by electron microprobe analysis (EMPA) were used to analyse the various well filler sand mixes. Points of analysis were indicated on backscattered electron (BSE) micrographs. Quantitative element mapping was undertaken by energy dispersive spectrometry (EDS). Thermodynamic calculations in FactSage predicted the percentage liquid phase present for the various well filler sand compositions at equilibrium conditions. The results of this work show that the degree of sintering of chromite-silica well filler sand depends strongly on the silica content. The amount of liquid phase formed increases with increasing silica content.

Procedure of determination of the cold compressive strength of samples of refractory inserts for composite plates of shuttles

The slide gate is the most advanced type of casting device. The design of this gate is based on the action of two refractory plates, which are in close contact with each other, one of which slides on the other, fixed motionlessly. Sliding gates can be of two types: with a lower movable plate, which carries out a back-and-forth movement in the horizontal direction using a hydraulic cylinder, and with a lower movable plate, which rotates around an axis. The shutter of first type is called a slide gate; the second is a rotary shutter.
 Monitoring of properties in particular strength of refractory inserts facilitates increase in operation reliability of constituent plates of sliding shutters in steel casting ladles. However, it is not possible to apply the existing standards for the compressive strength determination of these refractory products, because these standards do not provide for test samples with dimensions less than 20 mm. That's why the procedure MB 322-39-2021 was developed and implemented by JSC “URIR named after A. S. Berezhnoy” with the purpose of monitoring of cold compressive strength of refractory inserts for constituent plates of sliding shutters. According to this procedure, a method for measuring the compressive strength is used: the cross-sectional area of the test sample is determined, the maximum compressive load that leads to the test sample failure is measured, and the compressive strength is calculated.

Sintered material based on titanium carbide to increase the service life of slide gates

A new cermet material based on titanium carbide with a complex bond consisting of nichrome and nickel, additionally hardened with chromium carbide and a solid solution of chromium in titanium carbide, has been obtained. The influence of the technological parameters of the SHS-extrusion method (the delay time before the application of pressure, the pressing pressure, the speed of the press plunger movement) on the length of the extruded rod is studied, the optimal parameters are found. The microstructure and phase composition of the obtained material was investigated, the physical and mechanical characteristics were measured, and a comparison with analogs was given. It is shown that the microstructure, phase composition, and crystal lattice parameters of the phases do not change depending on the diameter of the extruded rod.

45 years of steel casting using slide gate systems in Russia

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Vision-based detection system of slag flow from ladle to tundish with the help of the detection of undulation of slag layer of the tundish using an image analysis technique

ABSTRACT It is very important to have a slag detection system (SDS) in steelmaking to detect slag and prevent its flow for improving the quality of steel produced. Slag raking is used for removing slag from liquid iron. Detection and control of slag may be carried out with the help of refractory dart or infrared imaging in the steel making zone such as in a Basic Oxygen Furnace (BOF). Each method has its advantages and limitations. Detection and control of slag flow from ladle to tundish in a casting operation is an important step towards cleanliness of the steel production. Various techniques such as ultrasonic level sensor, conductivity measurement using magnetic field, use of microphone to monitor the sound of steel flow through shroud, monitoring the radiation intensity of the stream of steel flow through a lateral side duct of the ladle shroud and monitoring of the shroud vibration have been explored to minimize the slag flow from ladle to tundish. It is obvious from literatures that non-contact based SDS is much more preferred using advanced instrumentation techniques. The problem with the vibration-based system is reduced metal level in the tundish due to setting up of slide gate of the ladle at low flow level as well as non-detection of the slag flow where vortex did not form prior to slag flow. Research showed improved performance with the vision-based caster SDS. Monitoring the sudden brightening of the slag surface around the pouring tube with the help of a CCD camera and image processing technique is also an effective way to detect slag transfer from ladle to tundish. The major limitation of this method is that a significant amount of slag already enters the tundish due to increased flow rate at the end of the tapping before splashing takes place. This work attempts to overcome this problem. There is an increased trend in the amplitude of the undulation of the slag surface of the tundish before the sudden brightening of the slag surface. If such undulations are identified by image analysis technique, signal can be generated to move the ladle slide gate to limit a significant amount of slag flow into the tundish. This would help to improve the quality of the steel that is produced.

Sintered Material Based on Titanium Carbide to Increase the Service Life of Slide Gates

Sintered Material Based on Titanium Carbide to Increase the Service Life of Slide Gates

Evaluation of the Addition Refractory Waste as Aggregates in Concrete for Impeller KR

Refractories, materials used in steel works, are directly or indirectly, associated with a very wide range of environmental problems. When discussing the influence of refractories on the environment, one should consider: aspects related to the global environment, local environment, work environment and the generation of waste. Refractory wastes are historically disposed of as waste in industrial landfills. However, some of the refractory materials used have the potential to be recycled, contributing to environmental and economic sustainability. The addition of recycled aggregates in refractory concrete used to molded Impeller KR was evaluated for the development of refractory recycling technology after use. In general, the results of the dynamic slag test and industrial test indicated the potential of the use of recycled aggregates slide gate.

Numerical Simulation of In-mold Electromagnetic Stirring on Slide Gate Caused Bias Flow and Solidification in Slab Continuous Casting

Numerical Simulation of In-mold Electromagnetic Stirring on Slide Gate Caused Bias Flow and Solidification in Slab Continuous Casting

Application of Titanium Alloy and Titanium-Based Coatings in a Gate Valve during Oil Production

In the Caspian region, the Tengiz oil field has a high content of sulfur, salts and mechanical impurities, which contribute to the rapid deterioration of equipment. The use of titanium alloy allows reducing corrosion wear 2-3 times. Based on the analysis of the design of the slide gate valve, the most exposed parts were identified, which were replaced by Grade 5 titanium alloy. Bench tests of the slide gate valve were put into operation. Laboratory work was carried out to apply titanium-based coatings to steel samples. The result was a structure with a microhardness of 730-810 HV sufficient to protect it against corrosion wear.