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By Jovanir Francisqueto, José Fagundes, Nayara Neves Coutinho, Marco Túlio Costa

The purpose of this project is to increase the visibility of which will be daily produced on the hot strip mill (HSM). The forecast was performed through the implementation of an automated tool for weekly HSM production planning. The project was started with the definition of the weekly planning process, through the determination of the main business objectives, like as: priorities of service (customers and delivery date), definition of HSM’s rules and restrictions of operating resources. Using a sophisticated mathematical model, through the computational simulation is possible the experimentation of various production scenarios, allowing the visualization of volumes by type of sequence, clients / priorities, mix to be produced, cylinder change quantity forecast, better forecasting of the productivity of the HSM, consumption of utilities, within others. Main benefits: sequencing which production orders should be produced, reducing unforeseen stops due lack of material, improving the quality of the stock which allows the reduction of the aging of slabs in the slabyard and the vision of customer services. Computational simulation as a weekly planning tool achieve, with other benefits, to present alternatives for better decision making.

Oct 6, 2019

By Jens Kempken

A competitive landscape pressurizes the steel producers business, zero defect requirements from customers forces the operators for additional efforts in process control and quality management. The so called quality related cost, which include also rework, cost for downgrading or even scabbing of material is already a remarkable lever in a plants profitability breakdown. The introduction of advanced state of the art grades in the product portfolio requires already a budgeting for the expenses for R&D and quality management. PQA has been developed as a process and quality management software solution next to existing level 2 or level 3 automation systems. It is focusing on the analysis of process data, equipment information, in line quality measurement devices and trend analysis to obtain an answer whether the process is according to definition and expectation and whether the intermediate or final product can be shipped for further processing as prime material. Advanced analytics which are linked to an expert know how based configuration identifies deficiencies in the production and processing process. An intelligent, state of the art quality rating system evaluates tolerable deviations. PQA comprises the software platform including the database, data configurator and collector from the different sources in the production process and units. The core element of the platform is the knowledge based expert know how package defining process and quality determining fundamentals. The paper describes the structure of the software package, it gives insights on the expert know how package, process and quality evaluation and points out the customer benefits, cost reduction, improvement yield, customer satisfaction increase. The link to recent operational references is given.

Oct 30, 2017

By François DUMORTIER

Due to the increasingly stringent requirements and the needs of the automotive industry, galvanizing lines for automotive products have to be modernized and improved. Beginning of 2017, SEGAL, a Tata Steel CGL located in BELGIUM and fully dedicated to automotive market, placed an order to increase the line capacity from 550kt/year to 600kt/year to process a wider range of steel grades and improve the product quality according to automotive requirements. To improve quality, a major revamping of the skin pass was necessary. The objectives were first to increase the work roll diameter from Φ560mm to Φ650mm to be able to transfer the required roughness with low elongation on soft material and second to increase the rolling force and tension to reach higher elongation on high strength steels. The result was the adaptation of the whole skin pass mechanics. Old mechanical elongation system has been replaced by a completely new single AC motor with helical gearbox at each bridle roll. John Cockerill achieved such complicated revamping in a very short time since the shutdown started only 6 month after the contract signature. The shutdown down schedule has been optimized with pre-erection works and the teams working 24/7 to implement all the changes. The complete project (skin pass, furnace, loopers) have been adapted during the three weeks shutdown. Today the customer can use both 560mm and 650mm work roll diameters. Thanks to the use of the new 650mm work roll diameter, the customer is able to make the same elongation using a bigger roll force (average 20% more), which has strongly improved the roughness transfer to the strip and the removal of the defects. SEGAL is really satisfied able to produce and supply higher quality automotive products to his customers.

Oct 1, 2019

By Patrick Edward Connell

The next generation of the well-established 3-roll Reducing & Sizing Block (RSB), the RSB SCS® is the latest milestone in reducing and sizing technology for SBQ products. It offers enhanced bar quality, improved productivity, mill availability and economy as well as a simplified, safe and environmentally friendly operation. A newly developed modular drive concept of the RSB SCS® grants a smaller footprint in the layout, a reduced oil-lubrication volume and a simplified maintenance schedule. Intelligent engineering leads furthermore to reduced hydraulic functions of the RSB SCS®, which ensures a safe and environmentally friendly rolling. Another integral part of the RSB SCS® is an innovative stand changing concept, which allows automatic stand changing within three minutes. The new RSB SCS® also includes a Fast Remote Control (FRC) which enables the immediate adjustment of the roll gap against the rolling force (under load) within milliseconds. Size changes along the free-size range can also be made within the traditional billet gaps in less than five seconds. At the core of the future-oriented RSB SCS® is a real-time closed-loop control system called Size Control System (SCS®) acting with 3-roll stands adjustable under load (AUL) and / or the heavy duty stands. These features remarkably further improve the rolled tolerances and their reproducibility, and at the same time simplify the operation by means of an automated optimization of the process parameters for the rolled bars.

Aug 16, 2017

By Gerhard Richter, Norbert Asamer, Gerwald Decker

At various stages during their manufacturing processes - from casting to finishing before delivery - semi-finished steel and special alloy products must be cut and surface-treated as well. The requirements for the individual conditioning steps, however, can be quite different. For example, the work piece can be hot, warm or cold. At any rate, the product must always be perfectly prepared for the next manufacturing step - reliably, in the shortest-possible time and at the lowest-possible cost. For cutting and grinding, BRAUN has developed innovative technologies and highly flexible, tailor-made solutions which meet these requirements in the most optimal way. In particular, BRAUN’s cutting and grinding technologies can also be used for large-scale products.

Oct 1, 2019

By Paulo Rodrigues dos Santos Junior, Luciano Passos de Jesus, Vagno Dordenoni Beltrame, Vinicius Antonio Ramos Pin

Faced with an increasingly demanding and selective market, a thorough analysis of each step of the processes is required in order to achieve high levels of performance. In addition to a major factor of importance in the rolling process, due to its high price, the rolls represent one of the main items in the cost of hot coils production. Using the 6 sigma methodology, there were opportunities for improvement in the grinding process, fatigue analysis, improvement in NDT in rolls, as well as means to guarantee operational stability, which allowed the reduction of roll’s consumption and consequently the cost of production.

Oct 11, 2019

By Ronaldo Esteves Ribeiro, Jefferson Felipe Faria Clemente, Carlos Victor Francisco dos Santos, José Herbert Dolabela da Silveira

n recent years, the market for thick plates has been highly competitive, in this scenario the plates quality is a critical success factor. In this process, the quality of the cut in thick plates is one of the important requirements for the customers, by the visual aspect as well as the technical aspect of the plate application. In the shear line, the cutting is done by shearing to trim tips, subdivide plates, trim side edges, remove samples, eliminate defects, etc. The cut is obtained by the penetration of the upper knife in the plate, causing plastic deformation in a certain region and hardening. If the clearance between the knives is adequate, the cracks will be close to the centre of the plate thickness and will result in a good cut quality. This work will present the theory of cutting of thick plates, the types of shearing, the quality of the edge in the cut, the types and the main characteristics of the knives.

Oct 1, 2019

By Michaela Böberl

State of the art sinter coolers are working based on the cross flow cooling principle. Thus, only a part of the thermal energy can be used for heat recovery application. The other part of the cooling air is brought unused to the environment. Furthermore, environmental regulation regarding dust emission and intelligent usage of exergy are getting stronger. Therefore, Primetals Technologies developed sinter coolers based on the counter flow principle. The cooling air passes the sinter bed in counter-flow direction enabling a direct heat transfer from the hot sinter to the air. The exhaust gas temperature can be maximized by using the total heat of the hot sinter. Due to the possible usage of the total exhaust gas amount, diffusive dust emission is reduced to zero. Two types of counter flow coolers are in the portfolio of Primetals Technologies. One type is based on a stationary shaft, in which the hot sinter is charged. The flow of the hot sinter is in vertical direction from top to bottom, in counter direction than the cooling air. The second type is a circular hopper cooler. The hot sinter is charged on top of a moving bed. At the bottom of the bed the sinter is discharged. The cooling air flows also from the bottom to the top, following the counter flow principle. Depending on the requirements, one of the two counter flow cooler types can be chosen for optimized and efficient cooling of hot sinter..

Oct 30, 2017

By "Andreas Steinwandter

The demand for increasing energy efficiency and CO2 reduction is one of the global megatrends of our time. Although the steel industry suffers from a volatile economic environment, the steel plants are interested to find opportunities for sustainable cost reduction and put efforts into healthy solutions for the environmental. Integrated steel plants are trying to cut electrical power and energy costs as these are among the biggest cost factors that can be influenced and taking all the advantages they can. For the integrated iron and steel making route the interaction of waste energy utilization along with process energy demand, natural and metallurgical gases, steam and heating systems as well as power generation has to be considered. Potential energy sources, such as sinter plant, basic oxygen furnace (BOF) cooling stack or reheating furnaces are considered in order to elaborate an integrated energy concept. Especially electric power generation is an attractive option for steel plant operators since it can easily be connected to the existing power grid of the steel plant. When direct local use of waste heat is limited, the best option is to convert it to mechanical/electrical power with a Rankine Cycle. A stand-alone system, compact design with minimum operational costs in order to fit into the existing steel plant layout, are the main requirements of such units. The objective of this paper is to demonstrate economic feasible opportunities for energy recovery for sinter cooler and basic oxygen furnace with focus on electric power generation via ORC modules taking at the same time advantages of CO2 reduction by utilizing waste heat from the process. Furthermore typical arrangements and layouts of such solutions as well as basic economic calculations will be presented in the paper.

Oct 30, 2017

By Boryong Lee, Heedong Sung, Minho Park, Sunyoung Choi

Recently, the demand for ultra-thin steel plate with high hardness and strength has been increasing in various industries. In order to satisfy this requirement, steel company designs the chemistry with low CEQ and obtains the required characteristics through quenching and tempering process. Especially, these steels are accompanied by low temperature tempering as a necessary process. Unlike ordinary high temperature tempering steels, it is impossible to improve the flatness after low temperature tempering. Therefore, shape control in the quenching process is very important for securing the excellent quality flatness. In order to obtain flatness in the quenching process, uniform cooling inside the plate should be accompanied. However, the quenching process has limitations in estimating the temperature behavior during cooling because the plate temperature is lowered to room temperature. In this study, a thermocouple was installed inside the actual quenching plate to measure the temperature behavior during cooling and to establish the manufacturing conditions of the quenching plate to ensure excellent flatness quality.

Oct 1, 2019

By Esteban Ruisanchez Rodriguez

In this paper we will discuss the process of the grain size customization of the EBT filler sand in relationship to the technical characteristics of the furnace and its tap hole. By customizing the grain size distribution, the glassy area formed on the top of the tap hole varies and supports differently the metallurgical pressure of the molten steel providing increased free opening speeds. Taylor made sand improves therefore the free opening rate, reduces the tap to tap time and increases the lifespan of the tap

Aug 16, 2017

By Georg Keintzel

The origin and elimination of 3rd octave mill chatter is a frequently investigated topic since tandem cold mills are in operation. So far only chatter monitoring systems have been successfully deployed, but this implies speed reductions and therefore a significant loss in mill output. Primetals Technologies has developed a new system using active injection of damping in order to eliminate 3rd octave mill chatter. The new hydraulics-based ChatterBlock® Control has now been proven successfully in mill operation. 3rd octave mill chatter, typically occurring in a frequency range between 90 and 150Hz, is a self-excited vibration phenomena typically occurring in the rear stands of tandem cold mills. It can produce significant gauge variations and even cause strip breaks. 3rd octave mill chatter is characterized by a quickly diverging vertical vibration of the rolls for specific rolling conditions (material, mill speed, forces, gauge etc.). Its occurrence requires immediate speed reduction of the mill in order to avoid strip breakage and/or strip quality degradation. This phenomenon thus severely limits mill productivity. The first step to proof the industrial feasibility of the new system was its installation on stand no. 4 of a 5-stand tandem mill. The development process and first results of the industrial implementation will be presented in this paper.

Aug 16, 2017

By Jerin Russell

This paper presents a new instrument for real-time detection of excessively coarse material in the overflow pipes of individual hydrocyclones using a non-invasive acoustic measurement technique. The hydrocyclone is an important device used in mineral processing beneficiation circuits for classification of mineral slurries by particle size. It separates a single input stream into two output streams; an underflow of coarse particles that undergo additional grinding for further size reduction, and an overflow stream of finer particles that typically goes directly into a flotation circuit for recovery of the desired mineral. However the hydrocyclone is a major piece of equipment in the beneficiation process that has no instrumentation for directly measuring its performance. The parameters currently measured – inlet pressure, feed flow rate, feed flow density – are common to the entire hydrocyclone cluster which typically has three to twelve hydrocyclones. Thus no information is available to detect individual hydrocyclones that are operating poorly. The system described in this paper detects the presence of unwanted excessively coarse material in the overflow stream of a hydrocyclone using sensors mounted to the exterior pipe surface. It provides real-time monitoring, trending and alarming of the coarse material level. This enables operators to identify poorly performing hydrocyclones, and enables corrective action to reduce or eliminate the coarse material discharge. Improving the classification efficiency of individual hydrocyclones will improve the overall classification efficiency of a hydrocyclone cluster. This leads to less variation in the particle size distribution and slurry density in the flotation feed, which will in turn improve overall mineral recovery. The reduction of unwanted coarse material in the flotation feed reduces the accumulation of that material in flotation cells. This can lead to equipment damage, and unplanned shutdowns due to events such as blocked dart valves.

Aug 16, 2017

By Bimal Nathwani

This paper presents an overview of bearings failures with focus on steel mill applications such as continuous casting, rolling mills, multi-roll cluster mills and wire and rod mills. This paper will also provide countermeasures for prevention of these modes of failures.

Jul 30, 2018

By Luca Tommasi

Danieli complemented its wide range of production plants for the iron and steel industry with a further step upstream into iron ore pelletizing and beneficiation. Danieli has engineered and constructed a state of the art and fully automated pilot plant facility – pot grate and sinter box – at Altos Hornos de Mexico S.A. (AHMSA) Pelletizing Plant, Monclova, Mexico. Installation and commissioning were completed in October 2009. Key features of the pot grate include the avoidance of the need for operator intervention during the test, automatic system preheat, absence of dead time, heat recuperation system with an air/air heat exchanger, oxygen control in preheating and firing with zirconia oxygen analyzer, possibility to test deep beds up to 625 mm. A series of projects have been accomplished by AHMSA availing of the pot grate facility with the aim to enhance pellet plant productivity and to reduce operating costs. The results obtained by use of Danieli pot grate combined with the experience and skill of plant operators has shown significant technical and economical benefits thus fully justifying the initial investment made by AHMSA and confirming the importance of having an in-house testing facility in order to optimize industrial plant operations.

Aug 16, 2017

By Michel Rodrigo Luiz, Glaudistoni da Silva Félix, Osmar Duarte Junior

This article deals with a project to reduce the preparation time and threading the coils in the input section of a pickling line coupled to the cold strip mill (PLTCM) at ArcelorMittal Vega. The project developed serves for the detection and elimination of bottlenecks in the input section. The project was conceived by the philosophy of the Theory of Constraints (TOC) and Lean Six Sigma (6 sigma), here seen as sequencing serial / parallel in the preparation and threading the coils. In this context, a proposal to modify the automatic sequencing and reduction of interruptions due to failure of the automation / equipment confirmed its effectiveness reducing the total time preparation time and threading the coils in the entry section by 15%. This project was developed without investment costs, bringing gains on the order of US$613,769.00.

Oct 1, 2019

By Valeria Romina Stricker

Acerbrag es una empresa Argentina siderúrgica de 50 años de trayectoria, desde el año 2007 pertenece al grupo Votorantim de origen Brasilero. Se dedica a la elaboración de aceros largos para la construcción. La planta industrial cuenta con un proceso de acería integrado, horno eléctrico, horno cuchara y máquina de colada continua. La materia prima es 100% chatarra, característica que la diferencia del resto de las acerías del país. Debido a esto el enfoque principal de este proyecto es reducir el costo de fabricación mediante un “empobrecimiento” de la carga metálica a partir de la flexibilización de los límites de especificación. Esto implica un mayor control del desempeño de los procesos a fin de detectar posibles desvíos, para ello fue necesario implementar la utilización de herramientas estadísticas y gráficas para su monitoreo. La modificación en el mix de fabricación no muestra una alteración significativa en la composición química y propiedades mecánicas de los productos terminados, situación favorable para la continuidad del proyecto. Se observa además, de la reducción de costo esperada, una ventaja en la operación del patio de chatarra y el proceso de acería y en la utilización de chatarras con altos niveles de residuales tales como Cr – Ni.

Aug 16, 2017

By Johan PEERS, François DUMORTIER

Today, solutions to optimize Capital Expenditure (CAPEX) & Operational Expenditure (OPEX) for small capacity Cold Rolling Mills (CRM) as well as for high capacity CRM are available, as extensively described by various Original Equipment Manufacturers (OEMs) & steel makers. A suitable solution for small capacity CRM is to start with a single stand reversing mill (up to 400 ktpy, depending on product mix), which can then be expanded into a twin stand mill (up to 900 ktpy, depending on product mix). The main drawbacks in conventional practice are the off-gauge length in single stand set-up and the long downtime of the mill during the erection of the second stand. For higher productions CRM, it is common practice to directly select a new Pickling Line Tandem Cold Mill (PLTCM), with a high CAPEX. Is there an in-between solution that would allow to start with limited output and CAPEX, without jeopardizing the ultimate expansion goal (1.2 to 2 mtpy), for which PLTCM is the best techno-economical choice? In the absence of a solution, JOHN COCKERILL developed an integrated solution that limits the CAPEX in the first phase of development, without crippling affecting future endeavors through an easy and economically sustainable expansion into a PLTCM, without long production downtime. The solution consists of first installing a twin stand mill, expandable into a tandem mill thanks to a smart design of the line. It is therefore possible to limit the production to 900 ktpy in the first phase of the project and then convert the mill into PLTCM in the second phase to increase the production from 1.2 to 2 mtpy, depending on the market trends and financial capabilities. In summary, JOHN COCKERILL has developed a smart new layout in reversing phase combined with a brand new rolling strategy to optimize productivity and limit off-gauge, compared to conventional solutions (patents pending). In addition the layout enables an easy conversion to tandem mill without high over investments, which is more sustainable financially than the initial purchase of a PLTCM. Long downtimes to allow for capacity extension, detrimental to this phase-by-phase approach, are also avoided. Technical and process description of the new layouts and rolling strategies, together with CAPEX & OPEX descriptions of the phases are detailed in this paper.

Oct 1, 2019

By Enrique Francisco Somolinos Garcia-Morales

In this paper we will discuss the benefits of a very innovative way of introducing MgO in the blast furnace operation through the sinter, using mini lumps of dunite. By changing the traditional way of using an MgO bearing material in fines form (particle smaller than 5 mm), most of the MgO inserted material behaves as inert during the sintering process, with the effect of having the following parameters (among others) improved: productivity at the sintering bed, permeability inside the blast furnace, energy consumption, stability of the operation.

Aug 1, 2018

By William Sergio Flores Roman

Los aceros para armaduras de hormigón tienen que exhibir una buena relación entre resistencia y tenacidad que se ve reflejado en la performance del producto en servicio al ser aplicado a esfuerzos exigidos. Acerbrag es una empresa que produce aceros para la industria de la construcción teniendo en su gama los aceros de medio carbono para la fabricación de barras conformadas de dureza natural para armaduras en estructuras de hormigón. El objetivo de este trabajo es encontrar criterios de ventanas de trabajos operacionales y de control para la manufactura de aceros con buenas propiedades mecánicas en términos de resistencia y tenacidad. Este paper muestra los resultados de los trabajos realizados en las diferentes áreas productivas para conseguir un producto final con mayor resistencia a altas exigencias en servicio, además, reporta diferentes aspectos del proceso de manufactura del producto que van desde el ajuste de la composición química del acero, incluyendo criterios de propiedades mecánicas objetivos, criterios de calidad interna mostrando la microestructura de la barra antes y después de los cambios y finalmente la calidad dimensional y superficial de la barra nervurada, este último potenciando la falla prematura del material. Todos estos cambios, se ven reflejados finalmente en la performance de la barra, sometida a los nuevos criterios de exigencia en los ensayos mecánicos.

Oct 30, 2017