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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 Carlos Martins de Oliveira

The trucking industry is constantly seeking improvement and cost reduction of their vehicles, studying new lighter and robust materials to meet the needs of its customers. The objective of this work is to study the application of DCPD Telene, PU. R. RIM and PP-TD 20 materials in aesthetic components of trucks: bumper, calender, upper and lower bracket and side air deflector. A multifunctional work team was created to work in such parts of IVECO trucks. The work began with an analysis of possible improvements to the current parts and followed the subsequent phases: definition of new materials, virtual modeling, new tools, and durability test in vehicles. It could then be verified that the proposed DCPD Telene, PUR. RIM and PP-TD 20 materials showed greater strength, better painting surface, and reduced weight and cost in parts.

Aug 8, 2018

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 Davide Onesti

Electrode regulation is the technology at the heart of the AC and DC Electric Arc Furnace. As such, in the last decade it underwent continuous improvement to maximize the EAF performances, in terms of process efficiency, machine utilization and operator safety. Given this background, Danieli Automation’s efforts in the field of electrode regulation have been focused on fast response to scrap cave-in, compensation of supply variations, automatic resonance detection, transformer protection, dynamic regulation of the electrical and chemical set-points, coordination and control of slagging and foaming agents, arc irradiance supervision. An extensive analysis of operator utilization and feedback was also carried out to develop an innovative system HMI. In this field, the choice of the variables shown to the user is the key aspect to allow a prompt process evaluation by the operator, who can refer to a condensed set of useful data. This paper will describe the innovative features and embedded models of the electrode regulation module (Q-REG+) and the supervision HMI, together with the effects of their application on EAF process efficiency and system usability.

Oct 30, 2017

By Dalila Chaves Sicupira

A pitting corrosion study of welded joints of lean duplex stainless steel (LDSS) UNS S32304 has been performed. LDSS S32304 thick plates were welded by different processes commonly employed in equipment and piping construction: SMAW (Shielded metal arc welding), GMAW (Gas metal arc welding) and FCAW (Flux cored arc welding). The electrochemical behavior of different weldment zones (fusion zone (FZ), base metal (BM) and heat affected zone (HAZ)) was characterized both independently using an electrochemical microcell and together through whole sample analysis. The electrochemical method applied was performed in acidified glycerin, a process fluid of the biodiesel industry. The results were correlated to the microstructural features of the materials. Based on the results, is possible to conclude that the breakdown potential (Eb) of the fusion zone (FZ) was higher than the Eb obtained for the heat affected zone (HAZ). In general, top samples show higher breakdown potential than root samples and also the samples welded using filler metal 2209 has a better anodic behavior than the filler metal 2307. According to the results, GMAW welding process with 2209 as filler metal was revealed as the optimum chosen for application of 2304 duplex stainless steels in this case.

Jan 16, 2018

By Marcel Antonio Arcari Bassani

In the mining industry, it is common to have data collected in various formats. In an open pit mining operation, at the early stages of exploration samples are obtained from diamond drillholes. During the production stage, samples are collected from blastholes. The last is more numerous but less precise. From a geostatistical view, this dissimilarity has to be considered to integrate the two sources of information. To combine this different data, three methodologies were investigated: simple kriging with local varying mean, cokriging and ordinary kriging. The exhaustive Walker Lake data set was used and it is considered the source to obtain the true grades. Initially, samples were obtained from the exhaustive data set at a regular spacing grid of 20 x 20 meters. Next, samples were obtained again from the exhaustive dataset at a regular spacing of 5 x 5 meters and a relative error of 25% was added. Then, both data were used to estimate blocks using the three methods mentioned. The grade tonnage curves were compared with the true block grade distribution. Moreover, the block misclassification was evaluated. The results showed that ordinary kriging produced estimates closer to the true block grade distribution and reduced the block misclassification.

Aug 8, 2018

By Dyego Monteiro de Souza

This study compares the wear resistance of specimens lubricated with biofluids or mineral oil. Tribological studies were performed by ball-cratering test. In these tests were used as lubricants epoxidized soybean oil, castor oil and mineral oil. The specimens used were untreated and nitrided AISI 4140, while a steel ball AISI 52100 was used as a counterbody. In order to analyze the results obtained, the worn volume was calculated and the characterization of the crater, after the test, was made using optical microscopy and SEM. Wettability was also measured for the different surface condition and lubricants. As expected both specimens showed a smaller volume worn when lubricated with mineral oil due to inherent properties of this type of lubricant. Among the vegetable oils studied, the castor oil showed a better performance in the lubrication of the specimens untreated while on the nitrided specimen have shown less wear when lubricated with epoxidized soybean oil, indicating a difference in the efficiency of oils, as lubricants, depending on the surface conditions of the mechanical components.

Jul 31, 2018

By Lucia Vieira

Kelvin probe force microscopy (KPFM) can be used to monitor electrostatic charges on the surfaces of materials. In this paper, we describe the use of KPFM to evaluate the electrostatic effect induced by silver nanoparticles incorporated as clusters in diamond-like carbon (DLC) films, before and after scratching. The results are compared to those obtained for DLC films without silver nanoparticles. Raman spectroscopy was used to identify the DLC signature, and energy dispersive X-ray spectroscopy (EDX) was used to confirm the presence of silver in the film. The morphology of the DLC film containing silver was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The findings suggest that the incorporation of silver nanoparticles in amorphous materials could offer new options for electrostatic energy storage on the surfaces of these materials.

Jul 31, 2018

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 Edmar de Souza Silva, Antonio Augusto Gorni, Emanuelle Garcia Reis, Daniel Bojikian Matsubara

Controlled rolling followed by accelerated cooling, known worldwide as TMCP, aims to increase mechanical properties without toughness deterioration. The process principle is to promote the plate cooling with water jets along the range of the austenite transformation temperatures. The accelerated cooling process is only fully effective when controlled in an integrated manner, as it alone cannot ensure significant improvements in the final properties of steels. Plate surface quality depends on some parameters that must be controlled before the start of the plate accelerated cooling. Good flatness is essential to avoid irregular water accumulations during cooling. After the reheating process, the slab should have uniform temperature, uniform austenitic grain size and easily removable scale. The slab thermal and microstructural heterogeneities are inherited by the rolled plate and tend to increase further during the accelerated cooling. This results in flatness problems, high level of internal stresses and mechanical property variations. The descaling strategy is an extremely important factor and must be determined with great caution. It is important that scale thickness and distribution is uniform to ensure homogeneous cooling over the entire plate surface. Otherwise, there will be an uneven temperature distribution, which can cause serious problems of flatness, surface quality and mechanical properties.

Oct 1, 2019

By Thierno FALL

This paper describes the study of the work-roll during the hot rolling process thanks to a 3D model built with the Finite Element Method (FEM). In terms of computational cost, that method needs high resources compared to 1D model which are mostly used. However, the 3D model is built to have a better understanding of the work-roll thermal and mechanical behavior during the hot rolling process. The thermal model shows that the highest temperature reached during rolling are within the range of 500°C and 600°C. The thermal field input used to simulate the mechanical behavior of the work-roll shows a biaxial thermal stress state, in the circumferential and axial planes. However, a peak of radial stress is observed in the backup zone. It did not generate plastic strain but could influence the fatigue behavior of the work-roll.

Oct 1, 2019

By Bruno Alves Resende, Antonio Adel dos Santos

Temperature, microstructure and dimensions are the main material parameters to be controlled during hot rolling of steel. Although thermal mathematical models have long been developed and applied for hot strip rolling, each Hot Strip Mill (HSM) must have its own model adapted to its facilities. Thus, a mathematical model for temperature evolution during rough rolling has been developed for the Usiminas HSM at Ipatinga Plant. The model achieved a high level of accuracy, which was assessed by comparing measured values of temperature at the hot strip mill entry with the calculated ones, the difference ranging from 9°C to 17°C. Application examples have shown that the slab can be occasionally stopped before start of rolling for as long as a couple of minutes without compromising its further processing. On the other hand, if the transfer bar stops after rough rolling even for short time, further processing in the HSM can be hindered, due to excessive temperature drop. In case of such abnormal line stop, the model can be used as a tool for decision-making to either continuing the planned rolling schedule or to changing the route, thus improving the overall rolling process.

Oct 1, 2019

By Uazir Bezerra de Oliveira, Günther Staudinger, Michael Skorianz, Edo Engel

Oct 1, 2019

By Andrea Zanon

Slitting processes have been used for many years to increase the productivity of smaller diameter deformed bars, without making major investments in the rolling mill. This technology is used mainly for the production of reinforcing bars (7-20 mm diameter), but successful applications exist also for round bar production. The multi-slitting process enables to produce up to 5 bars starting from one billet, thus increasing the productivity of the smaller products. Danieli Morgårdshammar, world leader in the supply of rolling mills for long products, has been a front-runner in slitting technology since its first applications and has recently developed, first in the world, the technology to produce 5X8mm rebar. This process has been recently applied in BRSM steel, a company based in Bangladesh which is a worldwide benchmark for slitting technology performances. This paper presents the necessary modifications which need to be considered when developing a 5-strand slitting project (and multi-strand slitting projects in general), as well as the results obtained at BSRM Steel when the process was implemented in 2016, the first rolling mill in the world rolling 5X8 mm slit rebars.

Oct 30, 2017

By Christian Overhagen

In bar and wire rod mills, rolling procedures featuring three- and four-roll technologies are state-of-the-art to produce high-quality long products. While a rolling model for the three-roll process including an equivalent pass method was already presented by the author, pass design methods are dealt with in the current work. The geometry of the rolled product and roll grooves are described mathematically using functional contours, allowing geometric-numerical methods to be used for manipulation and deformation simulation of the rolled product. For a given pass, the output section is constructed using these methods. Roll force, torque and rolling power are calculated using the mathematical rolling model presented before. Interstand tensions are discussed as influencing parameters on the force, torque and power demands, as well as on the section shape. A mathematical model for the influence of interstand tensions on lateral spread is incorporated in the model. To complete the pass design model, elastic mill stand feedback is considered in terms of a fixed elastic modulus for each rolling stand, the elastic feedback and therefore cross-sectional variation due to elastic mill spring being calculated iteratively from the roll force by application of the Gagemeter equation. The interaction of section height and width faults due to elastic mill spring and spread variations is analyzed in detail and the consequences for the roll pass design are shown.

Oct 1, 2019

By Gustavo Borges Tiboni

The erosive wear caused by the impact of solid particles against a surface is a tribological phenomenon present in many segments of the industry, such as transportation, aerospace, mining, power generation, among others. The most usual method to set the wear rate is by measuring the mass loss of the material. In order to apply one technique with potential to determine the rate of erosion wear, this study developed a dedicated equipment and conducted preliminary erosion tests monitored by non-destructive testing known as acoustic emission technique (AE). This can be defined as a technique able to detect mechanical waves generated by the release of elastic energy accumulated in the material. Erosion tests were performed in order to evaluate the ability of equipment to collect data from AE and to correlate these data with the wear of the samples. Samples of low carbon steel eroded by the impact of angular aluminum oxide particles suspended in air at three different velocities: 45, 57 and 67 m/s. The impact angle between the particles and the sample was set at 30 degrees and the test temperature at approximately 20°C. The wear rate has changed with the velocity in accordance with the kinetic energy of the particles and the AE parameter RMS showed sensitivity to the variation of particle impact velocity and to the wear of the sample eroded. The rate of AE signals collected over time correlated with the flow of particles striking the sample, and with the parameters of energy, rise time and duration of the signal.

Jul 31, 2018

By Alessandro Pigani

Over the last 25 years the thin slab casting and rolling process has been gaining a major market share in the production of hot rolled strip, progressively eroding the areas previously of exclusive domain of conventional mills. This is mainly thanks to the competitiveness of the process over conventional ones, and to the growing ability of this technology to cover the majority of market niches, well beyond the boundaries of the commodity market. After having significantly contributed to the continuous expansion of this production mode and after an extensive campaign of theoretical research and physical testing in reference plants, Danieli has progressively developed over the years a new generation of thin slab casting and rolling layout, marking a new phase in the evolution of this process. The new step-ahead is epitomized by the name QSP-DUE. This configuration belongs to the Quality Strip Production (QSP) family, which is Danieli’s strip-quality-oriented thin slab based plants. The innovative features of the process are embodied in the acronym DUE, which stands for Danieli Universal Endless (Danieli patented technology – US patent n. 8087449, January 3rd, 2012). What makes this new concept different is the ability of “universal” rolling modes thanks to the fact that, now, within one single plant it is possible to perform coil-to-coil, semi-endless and endless rolling modes, making this plant a major technology innovation compared to the previous generation.

Aug 16, 2017

By Kurt Herzog

State-of-the-art automation information technology and connectivity enables the digitalization of steel production that goes far beyond conventional automation of industrial production. Initiatives have been started around the globe to foster digitalization like IIoT (Industrial Internet of Things) in the US, Industrie 4.0 in Germany or China 2025. Primetals Technologies is actively driving the digitalization shaping the future of steel production. Intelligent combination of sensor technology combined with digital models as well as quality and production planning and control systems leads to new dimensions in product quality and production cost reduction. New diagnostic ways allow intuitive fault tracing or processing to support faster maintenance. Digital assistants support both operation and maintenance using context-oriented or self-learned information.

Oct 30, 2017

By Stefano Scubla

DANIELI Q-MELT is the latest evolution of EAF concept to automatically control each stage of the melting process, from the electric power planning to the combustion optimization as well as the slag and steel metallurgy management for every operation required in the EAF cycle. The core of the automation system is the Melt-Model that automatically identifies deviations of the process control variables and corrects them to avoid losses or wasting of available energy sources. The real-time online off-gas analysis, via the in-situ laser system, promotes the process tracking and permits further optimization by a viable closed-loop control acting on fuel and oxygen postcombustion. A suite of supplementary stand-alone Technological Packages integrates the Q-MELT to further maximize the productive time and the utilization factor, supporting the operators to limit downtimes, avoiding misoperations and/or mistakes.

Aug 16, 2017

By José Adilson de Castro

In the integrated steel industries the sintering process plays an important role furnishing raw material to the blast furnace. In this work, a computational simulation of the sinter process is developed that is able to predict the most important phenomena within the sintering bed. The model is based on the multi phase concept with multiple components described by conservation equations of each component coupled with the momentum, chemical reactions and heat transfer. The model validation was carried out comparing the model predictions with averaged industrial data and local temperature measurements within the sinter strand. The model predictions presented good agreement with the averaged values measured on the industrial sinter process.

Aug 2, 2018