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By Mery-Cecilia Gómez-Marroquín

O presente trabalho trata da formação da ferrita de zinco a partir da mistura e posterior reação solido-solido entre o óxido de zinco e óxido de ferro - Fe2O3 puros em proporções equimolares. A faixa de temperatura onde teve lugar a formação foi entre 1073 e 1373 K. Testes de redução da ferrita de zinco sintética-ZF e pós de aciaria elétrica–EAFD foram realizadas usando misturas de CO e CO2 que variaram entre 50 e 100% CO. Ambos os testes (formação e redução de ZF e EAFD) foram suportados usando técnicas de caracterização física, química, estrutural e microscópica. No caso da redução, foi observado que tanto a temperatura como a percentagem de CO, foram os fatores que, mais afetaram a redução de ferrita de zinco contida no EAFD. A máxima percentagem de redução foi 85%, para 100% CO, 1373 K e 105 min, e 52%, para 50% CO, 1373 K e 105 min. Por outro lado, atingiu o 100% para 100% CO, 1273K, em 80.75 min, 60%, para 50% CO a 1373 K durante 105 min.

Aug 16, 2017

By Michel Rodrigo Luiz, Glaucio Augusto Polini, Leonardo de Souza Melo, Giovani Rodrigues, Giardini F. Lazzarin

ArcelorMittal's pickling and cold rolling line has been demanded to increase production since the installation of equipment in 2015. In addition to improving productivity related to these new equipment, several additional jobs were planned and executed on equipment already installed has been carried out in order to improve the efficiency of the line. The present work exposes what was done in the scale breaker (tension leveler) to improve the availability results of the section and consequently of the line.

Oct 1, 2019

By Gabriel Oliveira Glória

In the context of changing culture, the society is increasingly looking for environmentally friendly materials, the natural fibers appear as an option to substitute the synthetic. Among these natural fibers, the PALF fiber may be considered an option, but there is limited information about the flexural strength of epoxy composites incorporated with PALF fibers. Therefore, the objective of this work was to investigate the mechanical properties in bending tests of epoxy composites incorporated with up to 30% in volume of PALF fibers. The results showed that the PALF fiber increase the flexural strength of polymer composites.

Aug 16, 2017

By Anna Carolina Cerqueira Neves

Synthetic fibers have been gradually replaced by lignocellulosic fibers. Compared to the synthetic fiber, natural fiber showed economic and environmental advantages presenting interfacial characteristics with polymer matrices that favor the impact energy absorption by the composite structure. However, so far little has been reported about the hemp fiber embedded in polymer matrices, such as tensile properties. This study aims to evaluate the resistance in tensile tests of epoxies composites reinforced with different percentages of hemp fiber. Tensile tests were submitted with percentage of 0%, 10%, 20% and 30% incorporated hemp fiber in epoxy matrix. The tensile strength and deformation substantially increased the relative amount of hemp fibers incorporated into the polymeric matrix.

Aug 16, 2017

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 John Anthony Vasquez

During the last years Riva Acciaio Verona has taken the decision to invest in the route of a fully automated meltshop. The aim is to reduce at the minimum the operator's intervention from the bucket preparation till the ladle transfer to the continuous casting bay. The foundation for achieving the goal is the introduction of innovative technological solutions (fully automated cranes for bucket charge in the EAF, robots for sampling, etc. The paper underlines how the different solutions are based on the best practices to improve operator's safety and describes the different steps of the project, the different solutions adopted and the results in terms of production, energy savings, cost reduction and improved safety. Details are presented for: scrap yard management and bucket preparation, EAFs centralized controls and related robots for auxiliary operations (sampling, EBT cleaning, scraper for slag door automation, complete mass & energy balance based on process control), LFs centralized controls and process integration.

Aug 16, 2017

By Ivan César Lopes Diniz, César Romero Afonso Goulart Júnior

Mandrels are tools applied to manufacturing seamless tubes. In VSB plants (Vallourec Soluções Tubulares do Brasil), it is used in two mills. Mandrel and PQF Mills. This is an expensive tool due its alloy (hot work tool steel – AISI H13) and lengh (between 12 meters and 22,5 meters). An opportunity to apply mandrels from PQF in Mandrel Mill has been identified. However, mechanical properties of PQF mandrels must be improved. This work presents the heat treatment process of Quenching and Tempering developed internally at VSB to improve PQF mandrel properties aiming to achieve Mandrel Mill requirements. Hardness and metallography tests were performed before and after some steps of the heat treatment to characterize and validate the process.

Oct 5, 2019

By Mirko Jurkovic, Thomas Hueper, Jens Kempken

The high competition scenario pushes the steel producers business. Zero defect requirements from customers force the operators for additional efforts in process control and quality management. PQA® has been developed as an advanced process and quality management assurance solution. It is focusing on the analysis of process data, equipment information, inline quality measurement devices and trend analysis. The paper describes the structure of the advanced process and quality management assurance solution PQA®; it gives insights on the expert know-how, process and quality evaluation and points out the benefits like cost reduction, improvement yield and customer satisfaction increase.

Oct 1, 2019

By José Aparecido Pereira

The customer asked for a 5” angle roll pass design. For this angle, in a normal pass design, a 160mm billet is required. For the production of this billet would be necessary a new 160mm mold for the Continuous Casting Machine, which produces 150mm billets, increasing the complexity of the melt shop. The rolling mill is designed to produce angles up to 4", technical information recommended the replacement of a gearbox because this process would generate torque up to 15% above nominal. An innovative roll pass design was done using 150mm billet using the Aparecido-W Method that cause a higher spread in the first three passes, thus reaching the desired leg length. As this method is not used in any other known rolling mill, a FES (Finite Element Simulation) and FEM (Finite Element Modeling) was done by a Research & Development center which demonstrated that the design was viable. From July, 2018, three tests were done being produced around 700 t of good quality products without difficulty of set up. The rolling mill team carried out this project at a very low cost and in record time of five months. The average torque of the motors was 36%, without overload for the equipment.

Oct 1, 2019

By Leonardo Araújo Peruch, José Fagundes, Henrique Carneiro Pinto, Marco Túlio Costa, Nayara Coutinho, José Fabiano Martins Assunção

The objective of this project was to increase the hot charge by reducing reheating energy consumption and raising the productivity of ArceloMittal Tubarão's hot strip mill by changing the HSM’s schedule process with optimization of the relocation process of slabs after HSM’s chance with focus on slab temperature in reheating time. The project began with the revision of metallurgical rules for the relocation of materials, definition of criteria temperature setting (hot / cold), definition of restrictions of the process and review of modus operandi scheduling process. With the implementation of the process / system it is expected to achieve a 10% increase in the hot charge index in slabs reheating furnaces and increase productivity of the ArcelorMittal Tubarão hot strip mill

Oct 3, 2019

By Chad B. Donovan

There is a strong need in North America and other major steel producing markets where major capital investment in new equipment has been minimal over the past several years to make improvements to existing casting machines. In many cases, very cost effective improvements can be made to existing equipment in order to maximize the efficiency and production of an older designed continuous caster, a classic caster. SMS Group and its predecessor companies have been maintaining continuous casting molds for over forty years. This experience has allowed SMS Group to intimately understand the advantages and disadvantages of each design. The most vital component of the continuous caster is the mold copper design, as it has the most influence over the ability to cast a quality product. Updating to a modern copper design is less complicated than most steel producers think and the benefits are significant. Premium mold coatings such as UniGuard® and NanoGuard® allow casters to guard against exposed copper and wear while producing quality products for record campaign lengths.

Oct 30, 2017

By John Hinton

Electromagnetic based (EM) sensor technology has been shown to detect changes in the magnetic permeability of steel strip travelling down the run out table after rolling. Measuring below the Curie temperature, these changes can be interpreted in terms of the phase transformation from austenite (paramagnetic) to ferrite (ferromagnetic). These real time measurements provide a detailed insight into the changes in the structure at high temperature providing the steel producer with feedback on quality control, product consistency and product development. However unlike mill microstructure models, the sensor measurement provides a point reading at a distance through the cooling course. To map the transformation in more detail, a sensor array is required along the length of the Run Out Table i.e. to measure points on the austenite to ferrite transformation curve. This paper describes the process and metallurgical factors that should be considered in the optimum design of a sensor array, i.e. the number and location of the sensor heads. Examples of cooling strategies for different steel grades e.g. low carbon, structural and dual phase steels are used to demonstrate the importance of sensor location. In addition, the effect of variability within typical industrial parameters e.g. cooling speed, on the sensitivity of sensor output and location will be considered.

Oct 1, 2019

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 Silvio Cecchini

State-of-the Art Mould Level Control Solutions for continuous casting applications face different challenges. On the one hand, technological phenomena such as clogging and unclogging, unsteady bulging or waving can create unpredicted meniscus disturbances by completely changing the casting channel geometry and the flow behaviour of liquid steel to the mould. On the other hand, from the viewpoint of caster operations, long lifetime, quick interchange-ability and integration capability into existing systems must be achieved. In the present contribution, the overall development of INTECO TBR’s mould level master – a comprehensive mould level control solution for all continuous casting applications – will be introduced. The basis for the presented system is a development over several years which includes investigations of all critical components such as shroud, stopper, stopper mechanism, servo actuator and mould level control program. These investigations finally resulted in a new-ly developed control algorithm for a highly dynamic servo actuator. The control algorithm with its basic functionality such as the prevention, identification and removal of clogging impacts with the associated automation functions to reduce their influence onto the overall mould level control performance will be presented. The scientific basis, the resulting control functions and their related automation implementation will also be illustrated. Finally, a patented control algorithm and control functionality for unsteady bulging and waving effects with the associated automation functions to reduce their influence onto the overall mould level control performance.

Aug 16, 2017

By Sébastien Gérardin

Developed for more than 30 years, continuously improved, cored wire is nowadays a reliable solution for the improvement of sustainability, safety, health and doing quality and cost saving. Cored wire allows the addition of ferroalloys and treatment of liquid steel, especially concerning the calcium treatment. Amongst all the processes in secondary metallurgy, calcium treatment is certainly the most critical one before casting. Besides the traditional CaSi and CaFe wires, new types of wire have been designed for becoming the new reference in calcium treatment. PapCal (calcium insulated wire) and HDx (high density calcium wire) are a very versatile range of products. Indeed, according to the steelmaking process parameters (steel grade, treatment temperature, ladle size, calcium content targeted in tundish and even injection conditions), their technical specifications may be adapted in order to optimize the calcium treatment as high as possible.

Aug 16, 2017

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 Karl Berger, Roman Schneeweis, Dietrich Mathweis

With increasing demands from customers to provide flat strip with tighter tolerances on material properties, particularly flatness of e.g. martensitic steel grades (M1500), it has become necessary to develop strategies to improve flatness without influencing the tensile properties for such hard steel grades. Usual skin pass mills are not capable to apply sufficient tension and roll force for these kinds of material to improve the flatness. Therefore, alternatives had to be searched for. This paper describes skin pass - / temper – rolling methods from the classical one to new alternatives in order to satisfy the demanding market of higher material properties and idle running mills in rolling plants.

Oct 1, 2019

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 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 Jean-Philippe Houde

The Blast Furnace Campaign lifetime is highly depending on the wear progress of the hearth lining. This progress is monitored in general through single and double thermocouples at the cold side of the lining. This type of monitoring becomes ineffective as soon as heat resistance will be formed in the refractory lining. Paul Wurth’s monitoring system, consisting of MTP-Sensor and Heat Flux Probes, is able to identify such heat resistances to give a true hearth lining wear. Since last year Paul Wurth is also able to install safely those MTP-Sensor and Heat Flux Probes on running blast furnace without salamander tapping, thanks to a newly developed cooled core drilling device. Blast Furnaces that are equipped with Paul Wurth’s monitoring system have optimized their campaign lifetime as they received right information upon the true wear lining such as detection of heat flux transfer failure, detection and monitoring of brittle layer or detection of hot spot.

Aug 16, 2017