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By Elizaveta Cheremisina

In steelmaking process lime serves as flux. Rapid lime assimilation and slag formation of the desired composition have a significant effect on the refining reactions. It is important to know the rate limiting step of lime dissolution to control and improve the converter process. Kinetics of pure CaO and industrial lime dissolution in model slag has been studied in the range of temperatures 1300 –1600°C. Lime samples were prepared in cylinder form and immersed in the melt for predetermined time. Considering the total mass balance of CaO in the slag and linear dimensions of lime samples, mass transfer coefficients were derived. Diffusion coefficients were calculated under conditions of non-stationary diffusion. The derived activation energy of less than 200 kJ/mol indicates that diffusion is the limiting step in the process of lime-dissolution in slag.

Oct 30, 2017

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 Paul Pugsley

The need for dimensional measurement of products has always been there, now with the industry 4 push to further understand measure and to record process parameters is more important than ever. This applies to both flat and long products, camera systems have always provided the method to measure, stereo Linescan cameras for flat products and innovative applications using 2D and Linescan cameras for long products. Instrumentation will become more important to producers enabling processes to be better controlled and understood, that aim being to make the production process understandable more repeatable and less reliant on operator influence. Primetals Technologies Ltd offer solutions for all types of products.

Oct 30, 2017

By Wolfgang Kern

The implementation of the Gas Treatment Plant (GTP) for CSPECEM, Ceara-Brazil is a result of the closed partnership between Paul Wurth Italia S.p.A. and DMT, the German leading company in Coke Oven Gas Treatment Plants. In addition to technical issues reducing emissions, avoiding of waste and saving environment and energy were technical challenges during the engineering phase. Below mentioned three descriptions of technical solutions represents examples of a number other innovations based on DMT’s know-how and experience in the field of by-product plants. Generally the design of the complete GTP is based on the consideration of modern features and design upgrading, with the aim of a safe operation with stable conditions and a long-living cycle of the whole of the plant.

Aug 16, 2017

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 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 da 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 afetarem a redução de ferrita de zinco contida no EAFD. A máxima percentagem de redução da ZF foi 85%, para 100% CO, 1373K e 105 min, e 52%, para 50% CO, 1373K e 105 min. Por outro lado, atingiu o 100% para 100% CO, 1273K, em 80.75 min, 60%, para 50% CO a 1373K durante 105 min. no caso da redução do EAFD

Aug 17, 2017

By Eric Schaub

Hot Blast Stove Systems are an important equipment of a Blast Furnace plant. During the last years, performance requirements and operation practice for the Hot Blast Systems have changed and have a big influence on the Blast Furnace operation. Therefore it is necessary to keep the Hot Blast System in proper condition in order to maintain the production capacity of the Blast Furnace. It is important for operators to know the condition and relevant constrains of a Hot Blast Stove Plant. Assessing its condition on a regular basis, especially in advance of a Blast Furnace relining is therefore advisable. Considering the individual condition of the Hot Blast Stove Plant, improvements in operation, but also specific and dedicated repairs might be implemented. Design improvements can be implemented as well during such repairs. This paper will describe some of these design improvements, will illustrate their implementation in new hot blast stoves but will also describe repair methods for existing stoves. In addition new developments became popular during the last decade, like the so called Dome Combustion Stoves, which was invented already 30 years ago in Western Europe. Paul Wurth’s development in this regard will be discussed in this paper as well.

Oct 30, 2017

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 Paul Riches

Today’s steel producers face the dual challenge of ensuring on-time delivery and ever demanding product requirements, while also running a lean operation. Every day the management of a long rolling plant requires continuous optimization of both operating and business practices. Imagine a long rolling facility, where individual pieces of equipment communicate with each other, where sensor information can be used not only for control purposes but to also monitor the condition of the equipment, where models are used to verify the process is within working limits and the equipment raises alerts to operators when it requires maintenance! Utilizing the ongoing evolution in technology though data collection, communication, internet of things, control techniques and smart sensors, there is now more information available than ever before. The collection and analysis of this information will both advance control and monitoring of plant performance; revolutionizing long rolling mill plants worldwide and optimizing the entire value chain, along with improved and more flexible production.

Oct 30, 2017

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 Maycon Athayde

Samarco produces high quality iron ore pellets processed in straight grate furnaces. This process is essential in order to obtain adequate mechanical strength to the pellet transportation and operation in the reduction reactors. All mechanical properties of the agglomerates are obtained during the stage of firing where the slag and sintering bond happens, thus it is a decisive step to improve the pellet quality. Therefore, the velocity distribution of gas flow within this zone must have homogeneous and even velocity distribution. Hence, it was developed a mathematical CFD model to characterize the gas flow in the burning zone, applying the equations of conservation of momentum, mass and energy and an uneven flow distribution was identified and the gas velocity analyzed and validated through experimental data. On the other hand, on the present paper, an improved firing zone burner were developed and industrially implemented in a way to mitigate the uneven flow pattern detected aided by CFD. Different burner designs, based on CFD analysis, were experimented in order to succeed on the aggressive condition. The combustion was investigated and burner efficiency evaluated and compared with the simulation purposed.

Aug 2, 2018

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 Michael McDonald

The cold-rolled steel output of cold-rolling mill (CRM) complexes are sometimes constrained by their batch annealing facilities (BAF). This paper examines a cost-effective solution to increasing capacity and quality of the BAF thereby making additional capacity available for CRM output. The solution involves applying a structured system of scheduling and operation to the BAF, using a proven level-2 software model. The system presented has been applied to a wide variety of BAF with all the leading furnace brands. Whether using traditional HN atmosphere or 100% hydrogen, peak performance can be achieved when using a properly configured, on-line, physical thermodynamic model. Given that it is not practical to place a thermocouple in each coil that is being annealed, various methods have historically been used to estimate the time required to properly anneal all the coils in the charge. This paper examines how the latest technology, in wide use throughout the USA, uses a physical thermodynamic model to shorten average cycle times, thereby increasing productivity and reducing energy consumption. The paper also examines the benefit of building thermodynamically balanced charges to further optimize the BAF operation and improve quality consistency by decreasing mechanical property variations.

Jul 30, 2018

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 Jari Larkiola, Aarne Pohjonen, Juha Jokisaari, Oskari Seppälä, Joonas Ilmola

Finite element method (FEM) is widely used to model the hot strip rolling process. Flatness defects e.g. front-end bending in multipass hot strip rolling is studied by authors using a finite element (FE) model with interactively operating automated controlling logic (ACL) [1]. However, industrial corresponding grade of accuracy in strip thickness subsequent to the rolling pass is not easily accessible in FE-model without separate calculation of significant rolling parameters and integrated roll gap control. In order to study flatness defects and optimize pass schedules the controlling and physics of the FE-model must correspond to the industrial process. For this need the automated controlling logic is upgraded by setup calculations to predicting roll force and work roll flattening. These predictions are utilized in setup positioning of a work rolls. Reliable setup calculation enables smooth multi stand rolling process without significant additional adjustment of roll gap clearance. State of art rolling technology requires above-mentioned setup controlling for the FE simulations to simulate different pass schedules without time consuming preparations. Operational setup calculations together with automated controlling logic of hot strip rolling enable simulation of new pass schedules and efficient problem solving.

Oct 1, 2019

By Renata Cristina Teixeira

The lubricant oil is a complex mixture of different basestocks and additives. Engine oils evolved from the use of pure mineral basestocks back in the early years of automotive industry to the advent of synthetic, fully formulated, low ash lubricants. This evolution was driven by a number of factors, such as new engine designs, extended durability needs, increased fuel economy needs, environmental concerns, feedstock prices and availability and legal issues. This paper uses technology prospecting on literature and patents databases to allow an investigation on the historical evolution of engine oils. Main basestocks (mineral, hydrotreated, polyalphaolefins, esters) and additives (antioxidants, antiwear, friction modifiers, detergents and dispersants) are characterized according to their research effort. Technology prospecting data is crosschecked against the evolution of engine oil classes, allowing an analysis of how the main drivers push the development of lubricant oil quality. A research effort was identified in late 1990’s until mid-2000’s and related to the adoption of chemical limits for lubricants. Different patterns for the articles and patents publication account for the high value technological knowledge has in this industry. Technology prospecting is seen as a useful methodology for the understanding and forecast of lubricant technology movements.

Jul 31, 2018

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 Jan Bak

Rourkela Steel Plant (RSP), which is operated by the Steel Authority of India Limited (SAIL), was inaugurated in 1959 and was the first Integrated Steel Plant in the public sector in India. In 2013, RSP commissioned their No. 5, 4060 m³ Blast Furnace, India's largest. It was built as a turn-key project by a consortium consisting of Danieli Corus and Tata Projects Ltd. and is entirely based on the technology and know-how of Danieli Corus. The new Blast Furnace is the key element of an expansion program that doubles the plant's production capacity and with much of the existing ironmaking capacity reaching the end of its technical and economic life span, it enables RSP to meet existing as well as growing demand for its products. This article discusses how this greenfield Blast Furnace was built in an existing and operating Integrated Steel Plant. It covers the accommodation of land, planning of the new installation to fit the available plot as well as the updated logistical lay-out of the plant. Technical details of the installation are presented, including their consequences for RSP's environmental performance and new perspectives for campaign planning.

Aug 2, 2018

By Fernando Ruiz Díaz

En aplicaciones a elevadas temperaturas como por ejemplo en cámaras de combustión y toberas de vehículos aeroespaciales se requiere el uso de aleaciones que permitan una elevada extracción de calor y buenas propiedades mecánicas. En este trabajo se realiza un análisis comparativo de las aleaciones Cu-Cr-Zr y Cu-Ag-Zr. Las mismas fueron sometidas a ensayos de resistividad eléctrica entre 25ºC y 700ºC y de tracción a 150ºC, 450ºC y 700ºC. Los resultados de los ensayos de resistividad eléctrica fueron convertidos a conductividad térmica mediante la relación de Wiedemann- Franz. A través de este análisis se observa que la aleación con mejor conductividad térmica es la de Cu-Ag-Zr presentando además un cambio de fase que no es observado en la aleación Cu-Cr-Zr. Respecto al ensayo de tracción la aleación Cu-Cr-Zr presenta mayores valores de resistencia a la tracción y tensión de fluencia a las temperaturas estudiadas.

Aug 16, 2017

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