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By Dustin Vickress

The premature failure of copper staves in the lower stack and bosh is frequently the cause for an interim blast furnace repair at great cost to the blast furnace owner. Protective accretions may form on the stave hot face, but when these accretions are lost the staves can begin to deteriorate both due to abrasive wear from exposure to the descending burden materials and due to thermal cracking from exposure to hightemperature process excursions. These mechanisms can lead to failure of cooling passages, which forces blast furnace operators to shut off these channels, accelerating the rate of copper stave wear. Finger cooler technology was developed to extend blast furnace life by restoring cooling to damaged staves. Evidence for their effectiveness is presented herein in the form of experimental test work and conjugate heat transfer (CHT) analysis carried out using computational fluid dynamics (CFD) simulations. These tests demonstrate that under typical blast furnace excursion conditions, a stave fitted with finger coolers will undergo half the temperature rise of a stave fitted with conventional cigar coolers.

Aug 17, 2017

By José Fagundes Jr., Juliano Braz Possatti, Bruno Câmara Vieira, Gabriel Godinho Alves, Bruno Bastos da Silva Murad, Cristina Maria de Oliveira Roque

Driven by market trends, increasing environmental accountability, government regulations and fostered by the Company’s strategic plan, ArcelorMittal Tubarão has developed new steel products to deliver better solutions to fit each customer’s needs. This often translates in higher strength, more complex and dimensionally challenging (thinner and wider) steels to attend a broad array of goals, such as reduction of vehicles fuel consumption and carbon emissions, increase in fatigue performance of heat treated parts, higher load capacity per net weight in vessels or wagons and lower supplying lead time as ArcelorMittal Tubarão establishes itself as a domestic option for so far imported grades. Based on the annual Product Development Plan, a structured workflow involves technical discussions from an operational point of view about safety issues, metallurgical project, steel grade family definitions, offline simulations prior to field trials, deformation resistance and process parameters adjustments and scheduling strategy. As a result of the increasing synergy between the areas, the share of new materials developed in recent years has been sustainably increased up to 15% in 2018, adding value to the final product without impact on hot rolled coil output and with a low cobble index.

Oct 1, 2019

By Tiago Fernando de Abreu e Silva Tomanik

Massa plástica refratária e placas isolantes têm sido utilizadas por um longo período em Fornos de Reaquecimento de Placas e Tarugos na Indústria Siderúrgica. Novas tecnologias para o revestimento refratário tem ganhado crescente interesse nos últimos anos em função da redução no consumo de combustíveis, redução em tempo e custos de manutenção e, consequentemente aumento de produtividade. Esse trabalho apresenta o desenvolvimento de um novo concreto isolante, de aplicação por projeção, para condições de alta temperatura, que permitiu a substituição do concreto denso na face de trabalho. Essa nova tecnologia permitiu uma redução no tempo de reparo e alta confiabilidade, pois suporta muito bem as agressivas condições da atmosfera do forno. Também será discutido o futuro desenvolvimento de projetos com significantes economias em energia.

Oct 30, 2017

By Marcus Vinicius Dias Garcia

O presente trabalho tem por objetivo contribuir para a preservação refratária de baterias de coque, apresentando uma metodologia de planejamento e controle. A condição dos refratários de baterias de coque é crucial para sua produtividade e para o cumprimento de diretrizes ambientais. São desafios (i) a identificação precoce de danos e previsão de seu efeito no desgaste global da bateria, para hierarquia de reparos; (ii) a seleção da técnica apropriada a cada reparo. No presente trabalho, os autores compilam o estudo da progressão de danos sob diferentes tipos de reparo ao longo de mais de 30 anos em baterias heat-recovery e convencionais, de diversos modelos construtivos, e o combinam a tecnologias de inspeção para consolidar uma metodologia de gestão da preservação refratária. A metodologia foi aplicada em baterias localizadas no Brasil, avaliando a condição de mais de 400 fornos em 90 dias. Para a bateria mais crítica, foi identificado um potencial de prorrogação de vida útil em torno de 10 anos.

Aug 17, 2017

By Wolfgang Kern

More and more coke oven plants worldwide face the task to improve their emission reduction at their coke oven batteries. In the 90’s PROven® was invented and developed by DMT to regulate the inner pressure of a single coke oven chamber. Generally, most of the coke oven chambers can only close and open their connection to the collecting main but without the possibility to regulate the pressure during the carbonization time. Through the installation of PROven® the load on the coke oven door sealing system and the charging lids will be decreased and so does the emissions of crude COG as well. The current PROven® system, installed in the collecting main, does not only regulate the chamber pressure, it replaces the valve between the goose neck and the collecting main, too. This variable pressure control allows decreasing the leakages at the emissions sources to a minimum and allows operating the collecting main under optimum pressure. Subsequently, this will lead to enhanced emission reduction. PROven® proved its value with more than 2,100 units installed by licensee worldwide. Nevertheless, DMT is always focused on its client’s needs and therefore enhance PROven® to provide the Best Available Technique (BAT). Among the main features of the now available system is the plain arrangement with a higher reliability and the possibility to install the system outside of the collecting main without modifying it. Hence, upgrading coke oven plants during operation is possible without any noticeable impact on the plant operation.

Aug 1, 2018

By Luiz Henrique Accorsi Gans

First, this works carries an experimental evaluation for austempered ductile iron (ADI) as a gear material. And second, in order to provide a better understanding of the microstructural effect on the stress state of subsurface regions, a finite element method approach was considered using the submodeling tool in ANSYS 11.0. For this, ADI gears were produced from continuous cast iron bars, heat and thermochemical treated and tested in FZG test rig. The results were compared to those of carburized steel AISI 8620 and induction hardened steel AISI 4140 gears. The wear experiments were performed at the temperature of 90ºC with two torque stages: 135 N.m (running-in) and 302 N.m (steady-state). The time for pitting and spalling on the gears surfaces were measured using image analysis. The results showed a very good potential of using ADI for manufacturing gears, replacing induction hardened steels. Also, the ADI gear with smaller nodules showed higher life for pitting. In contact fatigue tests with severe load, the carburized AISI 8620 steel proved more adequate than the austempered ductile iron, showing that the mechanical properties are critical in the resistance to damage in gear contact. The austempered ductile iron with smaller nodule size showed to be very competitive with wear resistance similar to AISI 4140 steel induction hardened. With ANSYS, it was verified that the nodule size affects the gears life independently of the mechanical properties of the matrix. The results showed that the nodules indicate the presence of a concentration stress, but their size doesn’t affect the contact fatigue life as much as the total amount of nodules, regardless of the ductile iron microstructure. The size and number of nodules affects both the nucleation and the propagation stage of cracks. ADIs with higher amount of nodules have a greater wear resistance. Also, compared to the Hertz contact theory (isotropic material), the presence of graphite nodules indicates a non-isotropic material and made the maximum shear stress point moves toward the surface.

Jul 31, 2018

By Delio Amorim

Industry 4.0 concepts is the new biggest challenge on the industry nowadays and every company in every industry in every part of the globe is looking to implement this somehow on their factories and machines. To do that on the newest long rolling mills, that brings already onboard state-of-the-art technologies, is for sure a challenge of machinery builder industry, but how to become the long rolling mills built on 70’s, 80’s or 90’s part of this innovation process and connected to the new trends? This is the main mission here, to show some examples of applications that goes in this direction.

Oct 1, 2019

By Manfred Hackl, Sergey Bragin, Alois Seilinger

The demand for hot rolled strip is growing in multiple ways. To remain competitive, new and existing mills must meet arisen challenges in the best possible way. The production of hot strip is a key element of steel production. Since close to half of all steel produced is hot-rolled to strip, mills require maximum throughput and availability combined with geometrical precision and the ability to create optimum material properties. Today there is a clear trend in developing new steel grades with high-strength and improved formability, like 3rd generation AHSS (Advanced High Strength Steels), as well as a trend to produce thinner and wider gauges. This trend challenges hot strip mills because it requires new technologies which provide more flexibility in metallurgical treatment during the rolling process. In order to meet and promote these trends Primetals Technologies is currently working on different concepts and solutions. One example is the development of a new mill stand technology Flex-HI HOT which allows to adapt the last finishing mill stands by efficiently switching from 4-high to a 6-high mode with small work roll diameter based on production needs. Another solution is to apply a permanent 6-high rolling stand at the end of the finishing train. A smaller work roll diameter allows to achieve higher specific thickness reductions and deformation rates resulting in significant thinner hot-strip gauges with valuable metallurgical benefits. The developed solution concepts with technological and metallurgical benefits will be presented in this paper.

Oct 1, 2019

By Luigi Giacomini, Bruce Kiefer

A new plant for special steel long products was commissioned in recent years at Dangjin, South Korea, for Hyundai Steel. Two multi-line rolling mills can produce yearly 1 million tons of billets, straight and coiled bars, with dimensions from 5.5 to 350 millimeters. The products are used for manufacturing engine and transmission components used by Hyundai Kia Automotive Group. The processed grades include carbon, special alloy, spring, bearing and free-cutting steel. The first mill rolls blooms into finished large round and square products, as well as into intermediate billets. A 2-high reversing breakdown stand is followed by a finishing and sizing train with CGA stands equipped with an under-load roll parting system for automatic gap control. The second mill combines lines of small bars, rods and bars-in-coil. Billets are rolled in a continuous rolling mill with original RedRing Series 5 stands. The rod outlet features Morgan No-Twist and Rod Reducing/Sizing mills, Morgan High-Speed Laying Head and Stelmor conveyor. Advanced sensors and electronics integrate with mechatronic packages, thus equipping the mill for Industry 4.0 applications. Hyundai can meet the demanding requirements posed by the automotive industry and benefit from optimized conversion costs, the flexibility to meet market changes, achieve high product quality, and reduce floor personnel.

Oct 1, 2019

By Gabriel Andrade Medeiros, Christian Brugger, Paul Pennerstorfer, Daniel Fuchshuber, Reinhold Leitnerl

State-of-the-art automation technology enables digitalization of the continuous casting process that goes far beyond conventional automation of industrial production. Primetals Technologies provides a digital twin that combines an intelligent digital representation of a casting machine as well as the casting process and the slabs, blooms or billets that are produced. It allows metallurgists and process engineers to predict the behavior of the involved complex production process and optimize parameters before using them in real production. New steel grades or production processes can be evaluated off-line without any risks to process stability and product quality. Primetals Technologies installs the digital twin with every new installation of a continuous caster optimization system. This paper describes how the setup and simulation possibilities of the digital twin provide numerous benefits by modelling and simulating the casting process. It allows for example the calculation of material properties according to the actual composition, strand surface temperature profiles and dynamic soft reduction before the final point of solidification. An outstanding feature of the digital twin is the replay functionality provided for various models to analyze and further optimize real production situations. The paper also gives an example how usage of the digital twin optimized production at a customer.

Oct 1, 2019

By Ruediger Holz, Tommaso Settimo, Luciano Vignolo

Optimized CAPEX, OPEX, new products, yield and product quality in new process equipment as well as by upgrading of existing facilities are the key factors for success and profitable operation. For this, innovation in processes and design is crucial. Danieli can support their clients by offering innovative and well-thought-out process equipment and upgrade solutions. In 2018, Danieli has put into operation a complete cold processing complex in Turkey, which includes a new continuous pickling tandem mill featuring latest generation of market oriented technologies. In this line, dedicated to run a broad range of size and grades (IF to AHSS as DP1000), the highly efficient Turboflow® pickling process was selected. This technology already proved its efficiency and ability in former applications handling ultra-thin gauges at speeds even exceeding 400 m/min in the pickling tanks. The 5-stand 6-high OSRT tandem mill features important developments, like actuators to improve significantly strip flatness and a special air knife arrangement on the tandem mill exit side to generate perfect strip surface cleanliness. In galvanizing lines, the zinc pot is the most effective area to reduce costs in operation and consumables and increase the product quality. Danieli has spent significant efforts in developing most advanced technology for the wiping process. A fully integrated system solution has been designed to perform a wiping process with high quality, economy, accuracy and productivity. Center part is the newly developed X-Jet / Compact X-Jet air knife, added by new generation electromagnetic stabilizer as well as robotic systems to reduce human intervention and health risks in this area. This technological package is ideal also for upgrade of existing lines, typically generating a return of investment less than 1 year. On top, Danieli has developed advanced automation systems including L2 and L1 controls to achieve outstanding product performances.

Oct 1, 2019

By Martin Dirks

Nowadays the sinter cooler often becomes the bottleneck of the sinter production, with outdated equipment leading to low productivity and high operation and maintenance costs. Furthermore valuable energy is simply destroyed in the cooler, which is not compatible anymore with a cost efficient and environmentally friendly sinter production. Paul Wurth has developed and improved two types of coolers, the annular cooler and the shaft cooler which offer flexible solutions to the specific situation of each client. The classic design of the annular cooler was completely revised and is now composed of a rigid ringframe construction as opposed to the traditional design with individual sintering cars, avoiding the typical problems of centering. Additional features of the PW annular cooler are the low air leakage rate and the increased effective cooling surface due to the removal of dead areas. This leads, in addition to the lower weight, to lower operating costs and a smaller space requirement. The shaft cooler stands out with an even smaller space requirement and a lower sinter outlet temperature because of a very long residence time of the sinter inside the shaft. Its development into a pure counter flow cooler aims at maximizing its energy efficiency, as it is designed as a system with a very low demand for cooling air, high air discharge temperatures and highly reduced dust emissions. For both cooler types flexible heat recovery solutions can be offered. These solutions include the supply of hot combustion air to the ignition hood burners and the sinter strand, the production of steam for the clients steam grid or the production of electric energy.

Aug 16, 2017

By Anderson Pereira

SORM 3plus (SORM = Superfast Optical Roughness Measurement) is a system enabling online measurement of roughness parameters during continuous strip processing. Increased requirements for new materials and more complex components call for ever increasing process safety. The roughness parameters are important quality features of uncoated and surface refined strips. The traditional method of measurement involves using a mechanical stylus based instrument. For this purpose the operator must stop the production line or samples are taken from the end of the coil and measurements are made offline in the lab. SORM 3plus, however, is a non-contact, online surface roughness measurement system that can be used for metallic and many non-metallic surfaces at strip speeds of up to 2400 m/min. The surface roughness data are stored in the system computer, displayed to the operator and if needed are fed into a higher-level network. The operator is alerted, if the limited values preset by him are exceeded or if any changes within the line will put at risk the production process. SORM 3plus calculates the roughness parameters as defined in the standards, such as the arithmetic average roughness (Ra) and the peak count (RPc).

Oct 8, 2019

By Božidar Šarler, Umut Hanoglu

A rolling simulation system has been developed to calculate the macroscopic rate of deformation, stress, strain, and temperature fields by using a novel meshless method. The model is based on two-dimensional traveling slice assumption. The slices are aligned towards the rolling direction. The initial size of the billet, bloom or slab and the geometry of the grooves at each rolling stand, the distances between the rolling stands, and continuous or reverse rolling can be arbitrarily considered. The purpose of this paper is to complement these development by predicting and visualizing also the grain size of steel over the strand cross-section for each position in the rolling mill. The grain size models have been in one-way coupled to the macroscopic calculations. First the critical strain for dynamic recrystallization is being checked. If the calculated strain is higher than that, considering also the time for meta-dynamic recrystallization, dynamic or meta-dynamic grain size calculations are carried out. If the strain is too low then only the static recrystallization is considered together with its required time. Finally, austenite grain size and ferrite grain size are calculated respectively as the steel cools down. The listed physical models are based on collection of empirical relations found in literature. The user of the system is free to choose or create the model he wants with his own parameters. The simulation system has been coded as a user friendly computer application for an industrial use based on C# and .NET framework and runs on regular PCs. The computational time for a rolling simulation is usually less than one hour and can thus be straightforwardly used for optimization of the rolling mill design in a reasonable time.

Oct 1, 2019

By Laurent Dorel, Sebastien Maillard, Afchine Nasserian, Jean-Paul Faure

Surface quality monitoring is primarily implemented in the last steps of steel manufacturing before shipment to the end user. However, an increasing trend for also addressing this topic in the upstream stages, such as hot rolling plant, is tackled by Primetals Technologies to give steel producers the key to a global optimized yield management, and efficient “lessons learned” processes. After the last developments of SIAS Next Gen platform, including High Resolution and Near Infra-Red, some site results will be exposed on the very specific high constraints lines such as ESP Endless Strip Production and Plate Mills, and highlights the related most interesting aspects for our customers.

Oct 1, 2019

By Yuechang Wang

A new method of manufacturing the wavy-tilt-dam(WTD) mechanical seal has been mentioned. In this method, the special equipment is designed to provide a predetermined force to external and inner circular surface of the ring. After milling the end face of the seal by grinding miller and releasing the preload, the wavy-tilt-dam can be done on the seal surface. In this paper, a prediction model is built up to investigate the relationship between the predetermined force and the deformation on the surface of the ring by using ANSYS software. A WTD ring is manufactured by this method which approves that the prediction model is in accord with the real process and this manufacturing method of the WTD mechanical seal is a proper choice.

Jul 31, 2018

By Laurent Dorel

Surface quality monitoring is primarily implemented in the last steps of steel manufacturing before shipment to the end user. However, an increasing trend for also addressing this topic in the upstream stages, such as hot rolling plant, is tackled by Primetals Technologies to give steel producers the key to a global optimized yield management, and efficient “lessons learned” processes. After the last developments of SIAS Next Gen platform, including High Resolution and Near Infra-Red, some site results will be exposed on the very specific high constraints lines such as ESP Endless Strip Production and Plate Mills, and highlights the related most interesting aspects for our customers.

Aug 17, 2017

By Woo, Hur, Kim, Ki Nam, Seung Min, Kyoung Sik

Tandem cold mill (TCM) is a process to obtain flatness as well as thickness desired by the customer by rolling hot-rolled coils continuously. The final stand of the TCM plays the most important role of flatness control, which usually uses the real-time measurement at the exit. However, as the material property increases, it is not easy to handle flatness with only the final stand. In order to overcome such a limitation, we propose a feedback control method to strengthen flatness control for non-final stands. The proposed method was tested in an actual production line, and the effect is proved for 45K or less steel grade.

Oct 1, 2019

By Günther Staudinger

Danieli Linz Technology has been honored at 4.1.2013 with the first contract for the exchange of a 350 t BOF converter for ArcelorMittal Poland Dabrowa Gornicza on a turnkey basis. This paper describes the new design features of this converter based on the development of a new Danieli converter suspension system. The issue was to install a new converter (incl. trunnion ring, suspension system and bearings) with maximum volume but keeping most of the existing equipment unchanged. So, the big tilting drives on both sides had to be reused and the existing foundation, pedestals as well as the bearing distance had to be maintained. Further on the welded coreequipment (vessel shell, trunnion ring, pedestals, slag shields, etc.) was manufactured in-house within the pressure vessel division of Danieli Thailand. Due to the huge dimensions of these parts the delivery had to take place in parts which had to be welded together on site under full production conditions of the steel plant. But also the erection had to be applied under this condition. Additionally the main support bearings, parts of the screening (doghouse) as well as an upgrade of the existing relining machine had to be delivered.

Jul 29, 2018

By Klaus Pronold

Once installed rolling mills can look forward to a long life. Around 40% of the 140 conventional hot strip mills presently in operation were built between 1960 and 1970. 17 of the 29 CSP®-plants were commissioned before the year 2000 and have automation platforms that are obsolete and/or have outdated rolling technology. Keeping pace with the market requirements is an ongoing challenge for producers of flat steel. It is a real balancing act keeping production facilities performing at necessary levels, safeguarding the investment and keeping outage periods to a minimum. To overcome these demanding factors and strike the right balance allowing for the production of higher grade steel that meets the current market price the installation of mechanical equipment as well as automation platforms and process technology must meet the latest technology standards. Being discussed in this paper are the different motives for modernizations along with their impact on project handling and commissioning philosophies. Experience gained during recent modernization projects in the field of flat steel rolling relating to Steckel / plate mills or current CSP® modernizations will be shared and demonstrate that each modernization has its own individual solution. Specific strategies are explained to help optimize production, increase plant agility and maximize the return on investment.

Aug 17, 2017