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By Jan Knobloch

Inter Stand Cooling (ISC) can increase productivity of a HSM and improve final mechanical properties of the strip. Constant Target Exit Temperature can be ensured for the whole strip length eliminating skid marks and other temperature oscillations of the transfer bar. The paper deals with advanced control module of ISC. Essential mathematical models of the control system is introduced and basic functionality is explained. Temperature model is based on FEM. Mechanical and thermal properties of the strip are calculated from chemical composition using neural network. Further on an experimental possibilities for investigation and design of ISC cooling headers will be shown. In conclusion practical experience with ISC on various HSM will be discussed.

Jul 30, 2018

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 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 Erich Bartel

The Kocks Rotation Mill - KRM- is an innovative elongation method for seamless tube production up to 4.5’’ diameter at production levels up to150,000 TPY. Using the principle of cross roll elongation, the machine rotates four rolls around the workpiece. A retained mandrel sets the wall thickness to a precision that exceeds existing industry norms. The KRM process performance has been truly excellent. Attributes include high billet weights, elongation of up to 9.5 in one pass, and eccentricity at or below +/- 5.0%. The flexibility of the process allows a wide range of steel grades to be produced at any wall thickness with little or no mill down time. Surface quality and yield are also greatly improved. Based upon the small foot print of the KRM rotor as well as the simple mandrel manipulation system, the installation cost of the KRM is significantly lower compared to other elongation methods. The reasonable cost of the machine, combined with greatly reduced foundation requirements, reduced ceiling height as well as simple utility connections reduce the initial investment for a new or upgraded mill. Finally, lower roll and mandrel costs allow high quality production at greatly reduces cost/ton.

Aug 16, 2017

By Christian Geerkens

Increasing requirements on slab quality initiates SMS group in developing products with a high sophisticated level regarding production and process. These characteristics are represented by SMS group’s HD family. HD stands for High Definition or the improvement of product quality via higher precision of the casting processes. A deep look inside into casting process is realized by the use of fiber optical equipped HD mold. High definition casting process control is assured using the HD spray and HD size. For objective, environmentally friendly and highly informative analyze of the inner quality of the cast products the new HD scan is present.

Aug 16, 2017

By Jefferson Lisboa Lelis, Marcos Roberto Soares da Silva, Maiara Rodrigues Gouveia

Nowadays, due the development of new hot rolled strips at USIMINAS, established the necessity of realizing studies to define new parameters for the welding machine of new pickling line, in order to improve mechanical and metallurgical properties of these materials. The aim of this study was to evaluate the weldability of high strength low-alloy steel with low boron content with tensile strength above 600MPa.The influence of energy input and preheating temperature on the mechanical properties of hot rolled strips were analyzed at three distinct thickness (2, 4 and 6 mm). To perform these evaluations were used tensile test, micro-hardness, metallography (micro and macro examination) and scanning electron microscopy analysis. In resume, a good welding performance was achieved, increasing preheating temperature and the welding energy higher than 60%.

Oct 13, 2019

By Bruno Kneipel Neto, Mylena Inaiê Correia, Fabricio Cerqueira, José Francisco da Silva Filho

The automotive industry, when aiming to increase the resistance to corrosion, uses in the Body in White (BIW) concept the galvanized steels. The hot-dip galvanized steels that stand out most are known as GI steels. They are formed by the zinc element and by phases of intermetallic intermediate iron-aluminum-zinc compounds. The characteristic properties of the GI coating are directly related to the formation of the intermetallic layer, which is responsible for providing the connection between the metal substrate and the coating layer. In this context, two different types of steel (SAE1005 and TRIP780 steel) were used for laboratory characterization of their intermetallic layers through metallographic techniques. The results of the tests showed that the inclined section metallographic inlay technique allows obtaining a larger region of analysis of the intermetallic layer. For the surface analysis, it was observed that the chemical solution used in the preparation of the samples was effective, making possible an analysis more specific about the intermetallic layer formation, distribution and morphology.

Oct 12, 2019

By Andrelio Marcos Ribeiro, Lucio Ribeiro Camisao, Antonio Carlos Ataíde, Alan de Sousa Pereira, Renato Siqueira Campos

The annealing and pickling line n. 1, responsible for the production of stainless steel 3xx, 4xx and 430a in thicknesses from 4 to 0.4 mm, has two vertical strip accumulators. These are intended not to let the material exceed the determined time in the furnace and in the pickling, and consequently do not cause defects like burning and excessive pickling. Strip accumulator n. 1 avoids the line from stopping during welding execution of the coils in the welding machine. In sequence, the strip accumulator n. 2 avoids the line from stopping at the end cutting of the tips, and in the coils removal from the pickling. The strip accumulators have a roller table that during the strip accumulation moves vertically downwards while its counterweight moves vertically upwards, and do the inverse movement when the material is released. On December 12th 2018, the failure occurred in the strip accumulator n. 1, where it was verified that the shaft of one of the pulleys had been fractured by high-cycle mechanical fatigue, which was characterized by alternating bending. With the fracture of the shaft, occurred the unevenness of the counterweight that damaged the guides. Failure analysis of this occurrence was based on the PDCA methodology, when was verified a weld between the shaft and the pulley. The analysis of the microstructure transformation in the molten zone, in the heat affected zone and in the base metal was carried out in an optical microscope, and no abnormality was observed. It was also carried out the end test by penetrating liquid, finding an inadequate weld in its geometry, as well as longitudinal trunks along the center of the weld bead. However, after a huge investigation of the causes, it was found that the failure was triggered by an inadequate design of the pulley shaft. It was also verified that the shaft had an open measure, inadequate for the operational context. After the analysis, action plans were drawn up based on the FMEA methodology to inhibit the failure recurrence.

Oct 7, 2019

By Josef Maierl

For the production of advanced high strength steel grades (AHSS) like API X80/X100, dual-phase, martensitic and complex-phase grades a number of hot strip mills need to extend their limits in terms of power and flexibility. Especially for cooling and coiling of these new materials, Primetals Technologies developed the “Power Cooling” and “Power Coiling” technologies. Power Cooling combines the advantages of conventional laminar cooling or “low pressure cooling” with the newly developed “high pressure cooling” with highest cooling rates for flexible operation. The Power Coiler which is needed to coil those high strength grades especially at thicker gauges ensures reliable strip-coiling for a most economical production. To enhance the reliable production of high-strength steel grades for a wide range of strip dimensions, the automation system with its advanced models is an integral part to the mechanical design. In this context the paper presents examples for the installation of power cooling and power coiling in new and modernized HSM.

Aug 16, 2017

By Leandro Rigo Ramos, Marcelo Lucas Pereira Machado, Lumena Gloria de Souza Nunes, Mariana Valinhos Barcelos

The aim of this work was to study the influence of temperature on the grain refining process from severe plastic deformations through the simulation of Accumulative Roll Bonding (ARB) by torsion tests. The assays were performed to simulate the ARB at three different temperatures of 550 ° C, 625 ° C and 700 ° C with 5 torsion cycles with equivalent strain of 0.8 per cycle at a rate of 0.1−1 , totalizing an accumulated deformation of 4.0. Grain refining was obtained with an average size of 2μm, 5μm and 6μm for the temperatures of 550 ° C, 625 ° C and 700 ° C respectively. There was a rise in Vickers hardness by 68%, from 119HV in the annealed sample to 175HV in the deformed sample at 550 ° C. In the deformations at 625 ° C and 700 ° C the value of 130HV E and 150HV respectively was obtained. Based on the obtained results, it can be stated that the severe plastic deformations in microliged steel, carried out at temperatures lower than the end of the austenite-ferrite transformation, produce refined grains of the order of 2μm and, consequently, increase the mechanical strength of the material.

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 Mario Andres Albuja Ribadeneira

El presente trabajo pretende encontrar la ruta para incrementar la productividad y reducir el costo de transformación en una acería eléctrica, mediante el uso de la tecnología disponible en el mercado. El método para alcanzar los resultados se enfocan en una drástica reducción de los tiempos de transformador conectado (power-on), los tiempos de transformador apagado (power-off) asi como la reducción en los consumos de las materias primas e insumos para la fabricación de acero por la ruta del horno eléctrico. La experiencia de Adelca arroja resultados que sobrepasan el 100% de productividad y 30% de reducción en el costo de transformación de la palanquilla. Los resultados obtenidos sin duda alguna servirán de una guía probada para quienes buscan un mejor desempeño en el negocio del acero.

Aug 16, 2017

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 Karl Berger

Today we are talking about Industry 4.0, as the latest revolution of industrial processes and progress, considering that the steam engine (Industry 1.0), railways and cars, mass production in the 1920th (2.0), Industrial Automation (3.0), and finally integrated manufacturing, integrated communication, and internet (4.0) can be seen as the state-of-the-art situation in industry, nowadays. Similar to the Industry progress, we can approach the rolling process of material, which started about 150 years ago in a very basic way. Steam engine- and belt driven-mills were very operators’ intensive, brutal and risky to operate. Mechanical improvements brought throughput, safety and quantity, as also quality of the products. The rolling of steel, in particular of rails, beams, rebar, strip (focus in this paper) and plate has enabled the large scale transport and travel, the building of bridges and buildings, the manufacturing of ships and cars. From single stands to continuous rolling trains the production and quality of mills increased significantly. From ingots and blooms to slabs, we have to admit a big jump in which has changed the face of the world significantly. Thin Slab Rolling has revolutionized the output and the throughput of rolling mills (Generation 3.0 to 5.0). Finally, Endless Rolling, has boosted the quality and quantity of rolling mill processes and permitted nowadays to enter in market niches which were not thinkable a decade ago. Mastering the automation and applying reliable systems (mechanical and electronically) of drives, actuators and sensors, as also communication and information interchange to all levels of automation are the success factors of such complex mills, we call herein after “Rolling Mills of Generation 6.0”.

Aug 16, 2017

By Edo Engel

Hot Blast Stove Technology has been developed to such an extent that low cost hot metal production for over 30 years without major repairs has become achievable, making the decision for a campaign length between 5 to over 30 years a design choice for the plant owner/operator. Some of the earlier examples of designs capable of such long campaign lengths are currently close to the 50th year of their running campaign. These examples are found especially in Europe and North America. Along the duration of these campaigns, repairs to subsystems such as burners, hot blast outlets etc. may be required. Depending on a plant’s up and down stream production capacities, the repairs may have to take place in the shortest possible time frame to minimize production loss. This article discusses an approach for intermediate repairs, executed while keeping the majority of the system at operating temperature.

Oct 30, 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 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 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 Juliano Braz Possatti, Arnaldo Carneiro Salles, Cleudson dos Santos Rego, Leandro de Lucas Mendes

The increase in customer demand for steels with higher surface requirements, associated with the need to increase ArcelorMittal Tubarão's HSM productivity, it was necessary the development of controls and actions to reduce scale losses within the scenario of high productivity. This article describes the path followed by the hot strip mill team in order to reduce the occurrence and severity of scales.

Oct 10, 2019

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