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By Breno Totti Maia

In these hard days for Brazil steel market, all steel shops want to achieve the same goal, work with: productivity, low costs and high performance. In this scenario the Slagless® technology (which is applied into BOF converter) was important to reach these targets. After use has been reduced the number of times of tip exchange in more than 04 times. Was reduced too, the time to remove lance skulls. Lance keeps clean during all his life with record number of the life 1255 .Blow keep stable due strong measure control at the nozzles and more improvements are planning.

Oct 30, 2017

By Giulio Rodrigues Altoé

Environmentally correct composites, made from natural fibers, are among the most investigated and applied today. In this paper, we investigate the mechanical behavior of epoxy matrix composites reinforced with continuous fique fiber, through bending tensile tests. Specimens containing 0, 10, 20 and 30% in volume of fique fiber were aligned along the entire length of a mold to create plates of these composites, those plates were cut following the ASTM standard to obtained bending tests specimens. The test was conducted in a Instron Machine and the fractured specimens were analyzed by SEM, the results showed the increase in the materials tensile properties with the increase of fiber amount.

Aug 16, 2017

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 Vitor Guarnier Domiciano

Pre-shaped refractory burner blocks play an important role in reheating furnaces operation and melt shops production since they are responsible for heating the billets/plates so that they reach the temperature required for lamination. This paper presents the main characteristics and properties of a new refractory castable developed for pre-shaped burner blocks, which significantly improved the performance of reheating furnaces burner blocks. Tests carried out in 3 different melt shops have shown that the new refractory castable was able to extend the service life of the refractory burner blocks from 1 year (standard product) to more than 3 years (new castable), showing perfect conditions to continue operating for a longer period.

Oct 30, 2017

By André de Cabral Oliveira

With the onset of the global economic crisis in 2008, and more precisely from 2009, production routes in iron making as blast furnace, sinter and coke oven, indicated a significant increase in frequency as well as intensity of undesirable incidents. The cost impact of such deteriorations of the production chain cause significant losses ranging up to several hundred million dollars annually. On the other hand, opportunities for processes improvement are contributing to enhance process efficiency and results, and also reduce or even avoid losses from unexpected incidents. The use of specialized services for processes has gained projection along the plants and emerged as an attractive alternative to increase results by increasing the performance and reducing costs and expenses. Process Services are formatted to achieve cooperative and customized solution during planned or urgent interventions, conducting feasibility studies, process improvement, training, among others, providing knowledge, information and crucial actions to preserve and optimize processes and plant facilities.

Aug 2, 2018

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 Claudio Pereira Diogo

A lot of galvalume/aluzinc steel sheet was furnished to a metallic roof manufacturer intended for tile fabrication. But, according with the roof manufacturer, that coils develops a different superficial aspect during processing. The purpose of this work was to provide an explanation for the appearance of the observed surface on one side of the coils. In order to find out the origin of the problem, mechanical and microstructural characterization tests were done at INSPEBRAS with the support of a partner laboratory. The results are described in this paper with their analysis and conclusions.

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 Eduardo Dominguez Trindade

Lubricant oils are subjected to reciprocating movement in the piston ring/cylinder tribocouple of automotive engines. In this kind of movement, the relative speed oscillates between zero and a maximum, and therefore the lubrication regime goes from boundary to hydrodynamic. Tribotests are widely used in laboratories to hint at the friction developed in these systems. In the present work, a SRV tribometer was used to evaluate the friction behaviour of lubricant oils under reciprocating movement up to 60 Hz. A high acquisition rate allowed the analysis of data inside each reciprocating cycle. Both a pure base oil and a fully formulated lubricant were used. Changes in the contact pressure, viscosity and speed were seen to influence friction, which was correlated to the relative thickness predicted by Hamrock-Dowson equation. While some observed characteristics were typical consequences of the Stribeck curve, other effects were also observed, such as the occurrence of seizure at high reciprocating frequency. A lower boundary coefficient of friction due to additive package in the formulated oil was also observed. The results allow a better understanding of friction in reciprocating cycles and can be used to evaluate the performance of oils and surfaces in laboratory prior to engine testing.

Jul 31, 2018

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 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 Douglas Glenn Stalheim

The uniformity of the final cross sectional microstructure and subsequent final mechanical properties and shape of structural steels is dependent on the type or types of recrystallization behaviors that are created. There are three main recrystallization behaviors that are the foundation of the metallurgy created during production. Alloy design and subsequent processing design strategy drive how much of each recrystallization behavior is created through the cross section of the product. Carbon manganese steels create only one basic behavior while the addition of microalloys, in particular niobium, can add two additional behaviors. The behaviors are intertwined with each other and build upon each other. The three behaviors are Type I, static recrystallization, Type II, no-recrystallization, and Type III, metadynamic/dynamic recrystallization. How much of each behavior is generated through the cross section through the production influences the final transformed microstructure and corresponding mechanical properties and shape performance. This paper will discuss the three behaviors, how they are generated, how to identify which behavior is occurring through modeling or actual mill data. Actual examples from production will be discussed.

Aug 16, 2017

By Alexandre Rizek Schultz

Silat, Siderúrgica Latino-americana, selected Russula as the main engineering contractor for their 700,000 tpy Greenfield steel plant dedicated to long and flat steel production. The project is currently under construction in the district Guararu in Caucaia in the metropolitan region of Fortaleza. The project will be developed in two phases. First phase: 600,000 tons per year rebar mill and 60,000 tpy steel mesh line; Second phase: 700,000 tpy melt shop (90 ton/hr EAF and 4 strand continuous caster for billets up to 180 mm x 180 mm).

Aug 16, 2017

By Guilherme Guidugli

The hot blast stoves are a regenerative heat exchange system, accounting for 10 to 20% of the total energy requirement in an integrated steel plant, responsible for the supply of about one-third of the blast furnace heat input and responsible for a constant flow of hot air to the blast furnace, according to the required production. Because of their important role in the hot metal production, a stable operation and an appropriate combustion control is necessary. This paper aims to present the results of an investigation and modifications performed as an operating multi-furnace plant, as well as the parameters considered to ensure thermal equilibrium, improving in the stoves heating cycle.

Aug 16, 2017

By Eduardo Vitral

The present study focuses in the simulation of pattern formation by ion beam sputtering on a material surface. This process is responsible for the appearance of unexpectedly organized patterns, such as ripples, nanodots and hexagonal arrays of nanoholes. A numerical analysis of preexisting patterns is proposed to investigate surface dynamics, based on a model derived from a Kuramoto-Sivashinsky anisotropic equation, in a two dimensional surface with periodic boundary conditions. While deterministic, its highly nonlinear character gives a rich range of results, making it possible to describe accurately different patterns. A finite-difference semi-implicit splitting scheme is employed on the discretization of the governing equation. Simulations were conducted with realistic coefficients related to physical parameters (anisotropies, beam orientation, diffusion). The study dealt with a random and a monomode 1D structure initial condition in order to understand how the shape and wavelength of the initial pattern evolve with time. Ripples and hexagonal patterns were observed in the results, being physically consistent with the phenomenon. Moreover, the Method of Manufactured Solution has been used as verification of the developed numerical scheme.

Aug 16, 2017

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 Stefan Stein, Jorge Davo, Adrian Villanueva, Abhay Kulkarni, Shane Hoff

Pellet sizing plays a key role in the productivity of the entire pelletization and subsequent induration processes, whereas uneven pellet sizing can increase the circulating load of the balling circuit inducing operational instability leading to production loses. The present work focuses in comparing the agglomeration kinetics, expressed as the number of pellets produced in a determined target size range, of different organic binder-bentonite binder systems. The batch experimental results show that the binder system has a great influence in the resulting pellet sizing, which could lead to advantages in terms of balling circuit efficiency and eventually operational de-bottlenecking.

Oct 1, 2019

By Fabiano Almir Barbosa, Eduardo Alves Machado, Felipe Ferreira Cajano, Bruno Rodrigues Henriques

Spring steels are usually classified as medium to high carbon low alloy steels with very high yield strength, enabling the part to return to its original shape regardless of significant bending or twisting. Despite the fact that plain carbon steels are suitable for small springs, larger and high performance springs usually requires alloy steels such as Cr-V or Si-Mn in order to achieve an even microstructure throughout the cross section. Clutch diaphragm spring is a high performance part that requires very good cleanliness and microstructure homogeneity, thus requiring an alloy steel. In this paper was studied, in an industrial scale, the process parameters and critical characteristics for the development of a Cr and V alloyed high carbon sheet steel for the production of clutch diaphragm spring. The steel was characterized throughout the entire process (casting, hot rolling, cold rolling + batch annealing and heat treated) using tensile test, hardness test, optical microscopy (OM) and scanning electron microscopy (SEM) to assess the mechanical and metallurgical properties of the studied steel. The results have shown the material’s microstructure evolution after each main stage of the process, from a ferrite-bainite/perlite based microstructure as hot band to fully spheroidized as cold-rolled/annealed and then fully martensitic as ready-to-use part.

Oct 1, 2019

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 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