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By Thais Pereira Dias Gusmão, Sebastião Ribeiro, Fábio de Araujo

Estudo de viabilidade técnico-comercial de remediação de lagoa eutrofizada por cianobactérias e algas, reuso em sistema de Utildiades e melhoria operacional atravpes de controles analiticos e fisico-quimicos.

Aug 1, 2019

By Georg Keintzel

The origin and elimination of 3rd octave mill chatter is a frequently investigated topic since tandem cold mills are in operation. So far only chatter monitoring systems have been successfully deployed, but this implies speed reductions and therefore a significant loss in mill output. Primetals Technologies has developed a new system using active injection of damping in order to eliminate 3rd octave mill chatter. The new hydraulics-based ChatterBlock® Control has now been proven successfully in mill operation. 3rd octave mill chatter, typically occurring in a frequency range between 90 and 150Hz, is a self-excited vibration phenomena typically occurring in the rear stands of tandem cold mills. It can produce significant gauge variations and even cause strip breaks. 3rd octave mill chatter is characterized by a quickly diverging vertical vibration of the rolls for specific rolling conditions (material, mill speed, forces, gauge etc.). Its occurrence requires immediate speed reduction of the mill in order to avoid strip breakage and/or strip quality degradation. This phenomenon thus severely limits mill productivity. The first step to proof the industrial feasibility of the new system was its installation on stand no. 4 of a 5-stand tandem mill. The development process and first results of the industrial implementation will be presented in this paper.

Aug 16, 2017

By Julio César de Oliveira Melo, Giuliano Felippe Soares, André Dias Leite

A resolução de problemas na operação industrial é algo complexo e precisa ser baseada em dados, muitas vezes diversos e não estruturados. Este trabalho traz uma abordagem em big data para dar visibilidade dos problemas em sistemas industriais, trazendo insights que permitam sair da intuição para assertividade, contruibuindo, assim, para redução do tempo de detecção e resolução de problemas.

Oct 1, 2019

By Paulo Masiero

Sintered titanium carbide has been extensively used since the early 1980s for demanding wear-resistant applications and, in particular, in environments characterized by high temperature and oxidation. Thanks to its physical characteristics, especially its low density, titanium carbide (TiC) has been successfully applied in the manufacture of cassette guide rollers for hot steel rolling. However, the peculiar characteristics of the sintered Ti carbides make it difficult their redressing and hence this has always represented the limit for a more extensive application. Very often iron based alloys are preferred even if, in general, they are less cost effective just because they are easier to be redressed by turning. The availability of a simple, compact, fully automatic and reasonably priced CNC machine; specialized in the grinding of guide rollers and able to operate accurately and efficiently -both in contour and in plunge- can definitively solve TiC’s redressing problems and render its use even more widespread and attractive.

Oct 30, 2017

By Jan Lückhoff

The introduction of the EAF Quantum furnace by Primetals Technologies represents an important milestone in the field of electric steelmaking during the last 15 years. In this process the latent and chemical heat of the off-gas generated during a melting process in an EAF is used to pre-heat scrap in an integrated shaft prior the melting of the scrap in the vessel. Combining proven own technologies, Primetals EAF Quantum enables nearly continuous process, cutting down idle times and enhancing availability for production. The essential benefits will be shown in this Paper.

Aug 16, 2017

By Samuel Vasconcellos

Em plantas de separação do tipo PSA ocorrem oscilações na vazão de ar intrínsecas a este processo, devido à repressurização dos vasos pré-purificadores ser feita em intervalos muito curtos. Por meio da instalação de um buffer tank foi possível tornar a coluna de destilação mais estável, aumentando a produção de líquidos, reduzindo a demanda de energia e otimizando a pré-purificação.

Jul 31, 2018

By Alexandre Patricio Vieira da Silveira

A thyssenkrupp CSA (TKCSA), Rio de Janeiro, possui dois Altos-Fornos. Ambos iniciaram operação em 2010, Alto-Forno 01 em 13/07/2010 e Alto-Forno 02 em 06/12/2010. Em Dezembro de 2014, foram verificados problemas de deslocamento dos staves de ferro fundido e deformação dos staves de cobre. Analisando estes eventos foi identificado quebra dos parafusos de fixação dos staves de ferro fundido na carcaça. O trabalho apresenta histórico destes acontecimentos, as intervenções realizadas como meio de preservar a integridade e prolongar a vida útil dos Altos-Fornos e os resultados obtidos após retirada de água do interior do mesmo.

Oct 30, 2017

By Bianca Proença

Fotocatalisadores de nióbio foram obtidos por anodização a 15 V, utilizando uma solução de K2HPO4 10% p/p em glicerol anidro como eletrólito por 15 minutos. As amostras foram caracterizadas por difração de raios-X para avaliação da estrutura cristalina obtida. A fotodegradação do glicerol (utilizado como agente de sacrifício) foi avaliada pela técnica de cromatografia líquida de alta eficiência.

Aug 16, 2017

By Ruediger Holz, Tommaso Settimo, Luciano Vignolo

Optimized CAPEX, OPEX, new products, yield and product quality in new process equipment as well as by upgrading of existing facilities are the key factors for success and profitable operation. For this, innovation in processes and design is crucial. Danieli can support their clients by offering innovative and well-thought-out process equipment and upgrade solutions. In 2018, Danieli has put into operation a complete cold processing complex in Turkey, which includes a new continuous pickling tandem mill featuring latest generation of market oriented technologies. In this line, dedicated to run a broad range of size and grades (IF to AHSS as DP1000), the highly efficient Turboflow® pickling process was selected. This technology already proved its efficiency and ability in former applications handling ultra-thin gauges at speeds even exceeding 400 m/min in the pickling tanks. The 5-stand 6-high OSRT tandem mill features important developments, like actuators to improve significantly strip flatness and a special air knife arrangement on the tandem mill exit side to generate perfect strip surface cleanliness. In galvanizing lines, the zinc pot is the most effective area to reduce costs in operation and consumables and increase the product quality. Danieli has spent significant efforts in developing most advanced technology for the wiping process. A fully integrated system solution has been designed to perform a wiping process with high quality, economy, accuracy and productivity. Center part is the newly developed X-Jet / Compact X-Jet air knife, added by new generation electromagnetic stabilizer as well as robotic systems to reduce human intervention and health risks in this area. This technological package is ideal also for upgrade of existing lines, typically generating a return of investment less than 1 year. On top, Danieli has developed advanced automation systems including L2 and L1 controls to achieve outstanding product performances.

Oct 1, 2019

By Gilmar Zacca Batista

The present work is a part of a comprehensive program that aims to evaluate the girth welding procedures for heavy wall API 5L X65 pipes produced for sour service applications. This article describes the results of toughness, strength and sour resistance of girth welds produced with different welding consumables. The methodology applied included girth welds production with GTAW process for root pass using ER70S-6 consumable and FCAW process for filling passes using E71T- 1CJ and E91T1-GM-H4 consumables. Mechanical tests of Charpy, CTOD, tensile, hardness and stress corrosion cracking were also performed. The E71T-1CJ resulted in a girth weld with tensile and yield strength around 7% lower than the pipe. However, according to the papers analyzed at this study, a value up to 10% of undermatching could be acceptable. The CTOD and Charpy tests showed good toughness and weld metal embrittlement was not observed. The hardness and the stress corrosion cracking tests demonstrated that the consumable ER70S-6 is suitable for sour service. All properties evaluated met the requirements specified by the onshore pipeline standards, showing that the consumables ER70S-6, E71T-1CJ and E91T1-GM-H4 are suitable for the welding of heavy wall X65 pipe with sour service and toughness requirements. If an overmatching is required, the E91T1-GMH4 shall be used to assure a strength overmatching and prevent plastic strain concentration at the weld metal. The results provided by this paper can be used for consumable selection and for welding procedure qualification of pipelines construction when heavy wall API 5L X65 are used for sour gas transportation.

Aug 16, 2017

By Rodrigo Martins, Mauro Trindade

I Reduction of energy consumption in air compressors by the implementation of individualized load control. Reduction of 3,5% from Jun / 18.

Oct 3, 2019

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 Antônio Augusto Martins

Os processos produtivos consomem elevados volumes de matérias-primas e insumos, apresentando excelentes oportunidades de redução de custo. O presente trabalho tem como objetivo desenvolver um sistema automatizado de dessulfuração em Carro Torpedo, tendo em vista que o sistema atual utilizava planilhas eletrônicas. Construído a partir das práticas operacionais, o modelo matemático para Estação de Dessulfuração em Carro Torpedo da Companhia Siderúrgica Nacional torna-se uma representação simplificada da realidade, possibilitando um controle de processo mais efetivo. O sistema de nível 2 possui um módulo de engenharia, onde todos os parâmetros operacionais e constantes de processo são definidos e um módulo operacional, que se divide entre o cálculo das adições de dessulfurantes e a avaliação de desempenho operacional. Nos primeiros meses de operação foi possível implementar um modo de operação padrão para todos os turnos operacionais que resultou numa menor dispersão das variáveis de controle.

Jul 30, 2018

By Felipe Darabas Rzatki

Polyether ether ketone (PEEK) is a high performance thermoplastic often selected for high temperature tribological applications under chemically aggressive environments. The present work evaluate the tribological behavior of a high performance PEEK composite under ambient and high temperature (30 and 80°C, respectively). The atmosphere was also varied (air or tetrafluorethane). An AMTI tribometer equipped with a hermetic chamber and a heating system was used to carry out sliding tests of PEEK cylinders on 304 stainless steel polished discs (Sq < 10 nm) with reciprocating movement and 175 N normal force. Surfaces roughness analyses were performed with a white light interferometer. As expected, there was a strong influence of temperature on the tribological behavior of the samples tested in ambient atmosphere (25% decrease in friction coefficient associated with a 100% increase in wear rate). On the other hand, samples tested in tetrafluorethane atmosphere showed no significant friction temperature dependence.

Jul 31, 2018

By Anna Carolina Cerqueira Neves

Synthetic fiber has been gradually replaced by natural fiber, such as lignocellulosic fiber. In comparison with synthetic fiber, natural fiber has shown economic and environmental advantages. The natural fiber presents interfacial characteristics with polymeric matrices that favor a high impact energy absorption by the composite structure. However, until now little has been evaluated about the hemp fiber incorporated in polymeric matrices. This study has the purpose of evaluate the impact resistance of this kind of epoxy matrix composite reinforced with different percentages of hemp fibers. The impact resistance has substantially increased the relative amount of hemp fiber incorporated as reinforcement in the composite. This performance was associated with the difficulty of rupture imposed by the fibers resulting from the interaction of hemp fiber / epoxy matrix that helps absorb the impact energy.

Aug 16, 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 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 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 Wenting Zhu, Liqing Chen, Junjun Cui, Zhenye Chen

In this presentation, a low carbon high strength steel microalloyed with Nb and Ti was processed by thermo-mechanical controlled process (TMCP) containing two stages of controlled rolling. The austenite with various grain sizes was obtained by austenitizing this hot-rolled steel at different temperatures. And the effect of austenite grain size on bainitic transformation was investigated in a dilatometer to reveal microstructural change. The results showed that the microstructure of the hot-rolled steel was mainly composed of granular bainite, lath-like bainite, and martenite/austenite constituents (M-A constituents). With increasing the austenitizing temperature, or increasing the austenite grain size, the microstructure was changed from granular bainite to lath bainite. When the steel was reheated to a lower temperature of 860 ºC, a relatively higher start temperature (Bs) was measured for bainitic transformation. This was mainly caused by the formation of solute-depleted region in the austenite and the promotion of the granular bainitic nucleation. The highest reaction rate occurred at austenitizing temperature of 1000 ºC with fine grain size, while the coarse austenite grain can lead to a sharp increase in the amount of bainite. An analysis was made on the kinetics of bainite transformation which was controlled by the volume diffusion of C atom.

Oct 1, 2019

By Dagoberto Brandão Santos, Marcus Vinícius Pereira Arruda, Fernando de Souza Costa, Túlio Magno Fuzessy de Melo

The development of advanced high strength steels (AHSS) is motivated by the automotive industry demands for higher strength steels with better formability and stretch-flangeability to avoid fractures during parts forming. In response to this, the new steel grades must have special microstructures in terms of constitution, morphology, distribution and hardness, which are strongly dependent on the chemical composition of the steel sheet and its processing, especially in the continuous annealing stage, in the case of cold rolled sheets. In this study the influence of the annealing heating rate and intercritical temperature (IT) on the microstructural evolution and the final hole expansion ratio of a cold rolled 980 MPa AHSS grade was evaluated. The annealing process was simulated using a Dilatometer and a Gleeble machine, and the microstructures were characterized using scanning electron microscopy, electron backscattered diffraction (EBSD) and nanohardness measurements. The increase of heating rate resulted in an overlap between ferrite recrystallization and austenite formation, changing the austenite morphology from a random to a fibrous distribution, while a higher IT resulted in more homogeneous microstructures and higher hole expansion ratios. This microestructural homogeneity, confirmed by nanohardness measurements, suggested that the difference in hardness between ferrite and the second phase affects the micro-void formation and crack propagation during the hole expansion test.

Oct 1, 2019