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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 Nestor Cezar Heck

Aim of the present work is to continue the theoretical evaluation of the slags of the fundamental system CaO-SiO2-CrOx-MgO (Ca-O-Cr-Si-Mg quinary system) at the temperature of 1,873 [K], with the help of a computational thermodynamic tool. Driving force for this and the previous research works is the understanding of chromium losses from the molten bath into the slag. Especially motivating is the presence of solid phases in the slag, since they may prevent refractory degradation and help in the production of foaming slags. Nevertheless, Cr-bearing solid phases can lead to Cr losses, being therefore detrimental. Determination of the states of thermodynamic equilibrium for this system using a slag with fixed composition as a start material were made using MgO amount as variable. Results show the impact of the MgO content on the equilibrium phases (molten metal, liquid slag, solids) and their composition for this system.

Jul 30, 2018

By Elen Mancini Santi Paulettor, Vinicius Calheiros, Eduardo de Oliveira Cabral

At this paper, Eirich will present its new tool for sinter analysis integrated to the sintering control system. For stabilization and optimal, continuous control of the sintering process, QualiMaster MT1, a device was developed which guarantees fully automatic representative sampling and material analysis and thus a high and stable sintering quality. Mining tailings often has a considerable proportion of valuable substances. In addition to this work, we will also present our mixing technology that allows the economic recovery of these mining tailings.

Oct 1, 2019

By Luiz Bruno de Oliveira Araujo, Luciano Morais Teixeira, Luiz Gustavo Pedrosa de Melo, Altair Lúcio de Souza

The off-line simulation of the metallurgical process in an industrial line brings several benefits such as: evaluation of the influence of the main parameters that affect the results of the process, comparison between different set ups, greater assertiveness in operational adjustments, process optimization and reduction tests for development of new products. With this objective, a software for offline simulation of the hot strip mill process of Gerdau Ouro Branco was developed based on the logic of calculations implemented in the online model. The software results in important process variables such as mill pass scale, load, torque, and power at each pass, temperature and the hot mean flow stress of the simulated material. During rolling mill process the strip presents different temperatures and time between passes for different points along the length, which directly influences the hot strength of the product and consequently in the calculated variables, thus the calculations executed by the software were divided to three points of the strip, head, body and tail bringing the individual results to each of these positions.

Oct 1, 2019

By Túlio Magno Fuzessy de Melo, Luciano Santos Marques, Vicente Tadeu Lopes Buono

The influence of the coiling temperature after hot strip rolling on the microstructure and on the tensile and hole expansion properties of a 800 MPa multiphase steel was investigated. For the temperatures between 150°C and 600°C the microstructure consisted of a ferritic matrix with a dispersion of fine martensite-austenite (MA) and regions of degenerated upper bainite. In all cases the ferrite presented a heterogeneous mixture of polygonal, quasi-polygonal and acicular grains. The yield and tensile strengths showed a tendency of decreasing with the increasing coiling temperature, probably because of the larger fraction of MA particles at lower temperatures and higher fraction of quasi-polygonal ferrite at higher temperatures. The elongation was not significantly affected by the variation of coiling temperature. The average hole expansion ratio showed a maximum of 80% for the material coiled at 400°C and fell below 50% only for the coiling temperature of 150°C, probably due to the larger hardness difference between the ferrite matrix and the MA particles.

Oct 1, 2019

By Leandro Augusto Viana Teixeira, Márcio Francisco Dill Junges, Adauto Caldara

Innovation in the mining industry is critical when facing ever growing challenges, like the need to increase safety, reduce social and environmental impact, deal with commodities price fluctuations among others. However, successful innovation is not only the product of technological innovation, but it is also dependent on Innovation Management, which consists of changing the way a company fosters innovation, creating a new structure able to leverage technology knowledge and the ability to convert this knowledge in value. This paper presents a restructure option for innovation that focus on R&D development linked to business needs and company strategy. This new system was approached based on four fundamental blocks for innovation management (Approach, Organization, Resources and Metrics), showing how the technology master plan and a management tool are able to bring together all aspects necessary for the proper operation of the system. The new system confirmed the importance of having the initiatives organized as innovation roadmaps, connecting techno-scientific development with the company needs through the use of KPIs that are relevant to the business.

Oct 3, 2019

By Roman Vaynshteyn

In places where Blast Furnaces are usually located, climatic factors may be unfavorable. Raw materials may be exposed to e.g. rain during transport/storage, bringing moisture into the process with consequences for stability and hot metal cost. This paper describes a technology for drying and pre-heating pellets and coke in the stockhouse. It does not require additional handling or logistical equipment and does not introduce extra transfer steps and degradation. Not only can moisture content be reduced, it can be controlled to a stable level by the operator.

Aug 16, 2017

By Marco A. Ramírez-Argáez

A 2D mathematical model was developed for the plasma arc welding process. Computational simulations based on mass and momentum conservation equations as well as Maxwell equations were performed by using the commercial software PHOENICS. The model predicts the electric characteristics of the arc column, flow patterns, temperature contours and electrical potential, by varying the composition of the cover gas, in this case, argon and nitrogen. It was found that an arc of nitrogen with respect to one of argon generates more intense jets, greater voltages, and lower temperatures in the arc column for welding arcs current of 150 A and 10 mm arc length.

Oct 30, 2017

By Gabriel Oliveira Glória

Due to growing concern about the ambient impacts, lignocellulosic fibers are been investigated to replace the synthetic ones in polymer composites The giant bamboo fiber, a relatively unknown lignocellulosic fiber with potential for composite reinforcement, still needs to characterize for possible engineer applications. However the giant bamboo fiber has low adhesion with the polymeric matrix. In order to understand the interaction that occurs between the bamboo fiber and the polymer matrix is necessary to evaluate its physical and chemical characteristics. Therefore, the present work analyzed the giant bamboo fiber by means of Fourier Transform Infrared (FTIR) spectroscopy. The spectrum revealed main absorption bands typical of giant bamboo fiber specific molecular interactions.

Aug 16, 2017

By Henrique Lacerda Eleutério, Aldo Henrique de Almeida Barbosa, Vicente Tadeu Lopes Buono

The automotive industry’s interest in galvannealed (GA) boron steel for hot forming processes application has been steadily increasing due to its excellent surface quality, galvanic protection provided to the parts, good paint adhesion and better weldability in relation to other coatings for this application. In this study, samples of 22MnB5 galvannealed steel were heat treated and hot stamped on a water cooled die in laboratory scale. The influence of heat treatment on stability of coating and steel was assessed by using initial heating rates 11.0ºC/s and 15.0ºC/s. Microstructural evolution of galvannealed coating and structural integrity of steel during hot forming were investigated by scanning electron microscopy with energy dispersive spectroscopy analysis (SEM/EDS/Line scan), X-ray diffraction (XRD) and optical microscopy (OM). It was possible to quantify the Fe-Zn phase evolution during hot forming, to understand the effect of these heating rates on the product properties and to establish an optimized heat treatment for hot forming of these steel. The heat treatment with the heating rate of 15.0ºC/s presented greater operational flexibility and final products free from surface defects or cracks in the substrate.

Oct 1, 2019

By Levi de Oliveira Bueno

Constant stress testing was used for characterization of creep behavior of a 1Cr0.5Mo steel plate in the ex-service condition. The tests were performed on creep machines equipped with Andrade-Chalmers type profiles, high sensitivity SLVC transducer extensometry, high stability temperature controllers, and facilities for monitoring the creep curves with an automatic data logging system. Ten creep machines of this type were used in this research, in an experimental work that lasted for one year. Three temperature levels were selected: 538, 565 and 593°C, with stress in the range from 52 to 224 MPa producing rupture times varying from 5 to about 3950h. The creep curves were all followed with great scrutiny using data logger scanning rates which enabled storing thousands of readings in each case. The experimental analysis involved measurements of minimum creep rate, rupture time and final elongation at rupture. The data were analyzed according to the classical phenomenological / physical relations (Norton, Arrhenius, Zenner-Hollomon, Monkman-Grant) and also considering five traditional parameterization methodologies (Larson-Miller, Orr-Sherby-Dorn, Goldhoff-Sherby, Manson- Haferd and Manson-Succop). Comparisons are presented among the possibilities of data extrapolation from five different methodologies. Comparison is also made with creep results obtained on a similar plate of the same material in the virgin condition.

Aug 16, 2017

By Andrew Slifka, Pello Uranga, Douglas Glenn Stalheim

Structural steel final mechanical properties of strength and ductility are predominately generated by the final ferrite grain size/packet size and homogeneity of that ferrite grain size/packet size through the cross-sectional area. Forty to seventy percent of the strength components come from how fine the final cross-sectional ferrite grain size/packet size that can be produced.[1] All the ductility properties of structural steels for a given microstructure are predominately driven by how fine AND homogenous the final cross-sectional ferrite grain size/packet size can be refined.[2,3,4] One key ductility property of structural steels used in construction and energy transmission applications is fatigue. Both low and high cycle fatigue can be realized in these end applications, however, low cycle fatigue is typically the predominate mechanism. In construction applications the environment for fatigue is typically air, such as in wind towers or high-rise building construction. In energy applications, there is an interest in high pressure (5.5 – 21 MPa, 800-3000 psi) gaseous hydrogen as an alternative fuel source to fossil fuels. A project to study the effect of the cross-sectional grain size/homogeneity of a relatively pure polygonal ferrite microstructure on the fatigue performance in air and high-pressure gaseous hydrogen has been developed. This paper will discuss the project strategy, microstructure developed for the project and initial test results.

Oct 1, 2019

By Vera Lúcia Othéro de Brito

Literature has shown that spinel Co-Mn ferrite have potential application in magneto-mechanical sensors, due to its relatively high magnetoelastic sensitivity. In this work, Co-Mn ferrite was processed by means of the ceramic method, using Fe2O3, MnO and Co3O4 as raw materials. Samples were liquid-phase sintered, using Bi2O3 additive as liquid-phase former. X-ray fluorescence analysis was carried out in the raw materials in order to evaluate their impurity content. Atomic absorption spectrometry analysis was used for quantifying the Co/Mn/Fe proportion in the ferrite. The microstructure of the sintered sample was analyzed by means of Scanning Electron Microscopy. The magnetization and magnetostrictive behavior of the ferrite were evaluated, obtaining curves for magnetic hysteresis, magnetostriction and magnetoelastic sensitivity. The impurity inclusions and the Bi-rich particles formed from the liquid phase were characterized. The sintered ferrite had a total magnetostriction of -126ppm, which is lower than the values reported in literature for a Co-Mn ferrite of similar composition. It was verified that sintering was carried out within a critical temperature range, in which the decomposition of Mn ferrites may occur when sintering in air. This decomposition affects the magnetic properties of the material, and it may be avoided by using controlled sintering atmospheres.

Aug 8, 2018

By Marcelo Rebellato, Beatriz Pereda, Beatriz Lopez, Pello Uranga

The classical application of Nb microalloying in the development of thermomechanical processes for flat products has been related to its suitability to enhance strain-induced precipitation and get a pancaked austenite prior to transformation. As new steel grades or new lay-outs are being developed, more complex metallurgical conditions need to be evaluated. In this context, Nb microalloying, alone or combined with other microadditions, needs to intervene in a more controlled way in additional steps of the thermomechanical process, besides its conventional strain-induced precipitation role. For example, the hardenability enhancement associated with Nb to properly achieve lower temperature transformation products, demands a proper balance of the Nb amount precipitated during rolling and the one remaining in solid solution. Similar effects are also sought when the final available Nb is used to increase strength through precipitation hardening. This manuscript evaluates how changes in the rolling strategies affect the interaction between Nb(C,N) precipitation and austenite recrystallization at different steps of the rolling process. As the possible interactions between parameters intervening simultaneously are quite complex, the application of microstructural models helps to properly define the best austenite conditioning combined with the convenient amount of Nb in solution, as a function of the final property requirements. Along the manuscript, several strategies will be discussed for the case of hot rolling of flat products comparing both normal and coarse initial austenite grain sizes.

Oct 1, 2019

By Walter Luiz Castro dos Santos, Leandro Resinentti Zanon

In the production of iron ore pellets, one of the factors that strongly influence the cost of ore-pellet processing is the specific consumption of natural gas that occurs during the thermal processing stage of the pellets. The filtration process is the step where the adequacy of the moisture percentage of the retained pulp occurs, so that subsequently there is the processing in the subsequent stages of the pellet formation and hardening of pellets. The water contained in the raw pellet is withdrawn at the stage of thermal processing. For this purpose, the literature indicates the demand of 600 Kcal/kg of water for the heating and vaporization of the moisture of raw pellets. The statistical analysis of the performance data of a pelletizing plant showed that for each decrement of 0.1% of water in the retained pulp is equivalent to the reduction of 0.091 Nm3 in the consumption of natural gas per tonne of pellets produced. Thus, the proper performance of the filtration stage is essential to reduce the percentage of pulp moisture retained and consequently to increase the energy efficiency of the pelletizing furnaces. The aim of this article is to present the main steps in conducting a work to increase the filtration performance to reduce the percentage of retained pulp moisture and the positive impacts on the specific natural gas consumption of a plant Pelletizing.

Oct 1, 2019

By Werner Klein

The Production Management solution (Level 3) covers TYASA’s existing steel making plant, billet caster and new Castrip based coil production line in Ixtaczoquitlan, Mexico. It steers the order based production utilizing product routing information and corresponding process instructions for the individual processing units. A seamless material tracking along the entire production route from heat creation in the electric arc furnace down to the final coil product provides TYASA with the genealogy information customers require for flat products. At each important process step the Level 3 compares actual quality related production results with order requirements. In case of deviations from ordered quality the plant staff is guided by rule based dispositions. The highly configurable solution supports customer to operate its production plant as a smart factory in the sense of industry 4.0.

Oct 30, 2017

By Klaydison Silva, Maurício Curi Segato, Elves Matiolo, Neymayer Pereira Lima

Flotation is the main concentration process, has been applied with sucess for the removal of quartz on the iron ore industry aiming high quality concentrates. limiting the top size close to 0,300mm and the removal of slimes are fundamental for the efficiency of reverse flotation of quartz. The high consumption of reagents, leading to insufficient particle coverage, and increased foam stability, leading to the difficulty of removal of quartz particles, are the main deleterious effects of the presence of slimes. Recent characterization studies, together with the development of new collector of linear chain, allowed the obtaining of concentrate with SiO2 contents close to 3% with 94% of metallurgical recovery, based on pilot tests carried out on a sample flotation column of the Quadrilátero Ferrífero.

Oct 3, 2019

By Humberto Almeida de La Serna, Kayleigh Meneghini, Gabriel Rubio Pirillo, Maurício Guimarães Bergerman

The Mining Annual Report (RAL) is an obligation for every current owner of a brazilian mining process which is already undergoing extraction. This document is basically composed by the company’s annual book balance, where is possible to educe informations that allow to evaluate the mineral market behavior. This research gathered filtered data linked with RAL production and technical responsability between 2010 and 2017, gotten by the Information Access Law, without the real CNPJ of each company, in order to preserve their identity. The results allow to quantify the Brazilian mining production during the period, illustrating that approximately 46% of the companies can be classified as micro, 30% as small, 20% as medium and 4% as large mining companies. It was observed that the micros concentrate the most part of technical responsibles who sign for more than three mines.

Oct 3, 2019

By Denisio Miranda Custódio, Rodrigo Boyer, Josiane Lira Batista Haagensen, Raquel Teixeira Pereira, Felipe Viana Pimenta, Rossano Augusto Pilon Nunes

In the Tubarão Pelletizing Plants, anthracite is used as solid fuel, which has fixed carbon content of 72%. This paper will present the pilot scale results and industrial scale tests of an alternative fuel to anthracite, named Blast Furnace Dust. All the work was developed using samples from Arcelor Mittal Tubarão, due to it has a large source of production and is near to Vale/SA, which reduces significantly the cost for the material’s transportation. There was an impact on the variability in fixed carbon results of the slurry, mainly at the beginning of the test, reaching very high levels and put on risk the pellets physical’s quality. This variation can be explained by some operational disturbances and, mainly, by the low predictability of Blast Furnace Dust quality and lack of an adequate system for material preparation and dosage.

Oct 1, 2019

By Walter Mazon, Marcello Rodrigues Cruz, Leandro Carvalhar Maciel

Filtration is the operation of liquid solid separation commonly applied in the mining industry. The use of filtering chemical agents is a technical solution viable for filtering optimization. The present work proposed to evaluate two filtering chemical agents (surfactants) to reduce the final moisture content of iron ore concentrate from Ferrous Resources. The leaf test top feed was done with the FLOTICOR FA 7241 and FLOTICOR FA 16557 products. The foaming profile of the filtrate was also evaluated, once excessive foaming is undesired when using this kind of products. The results showed a reduction in the final moisture of the filter cake. The product FLOTICOR FA 16557 achieved the best results, reducing final cake moisture from 10.4% to 9.8% at the dosagem of 25 g/t, besides presenting a fast kinetics in the foam drainage, presenting itself as a technical alternative for filtration optimization.

Oct 3, 2019