Search Documents

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 Renan Gurgel Pinho

O objetivo deste trabalho é investigar a esferoidização do aço SAE 1080 e os respectivos efeitos da variação do tempo na microestrutura final e na dureza do material. O aço SAE 1080 foi submetido a recozimento isotérmico, por tempo prolongado, utilizando-se 90, 100 e 120 horas de aquecimento à temperatura de 715ºC. Os resultados mostraram que é possível esferoidizar o aço SAE 1080 nos respectivos tempos escolhidos e perceber aumento da quantidade de esferoiditas, assim como decréscimo na dureza.

Aug 16, 2017

By Sandro Griza

Neste estudo, foi analisado um segmento de perfil em “U” que rompeu em serviço. O perfil compunha uma estrutura metálica em treliça que sustentava uma bandeja de construção civil. Foram realizadas análises de fratura, análises de caracterização do material e estudo de rigidez do perfil. O perfil rompeu por sobrecarga estática porque foi instalado do lado inverso. Isto desfavoreceu a rigidez da estrutura.

Aug 16, 2017

By Ana Carla de Melo Moreira Campelo

Para elaboração de planos de lavra é necessário que se faça o correto dimensionando da capacidade produtiva dos equipamentos envolvidos nas atividades de perfuração, carregamento e transporte. Esse estudo aborda o dimensionamento da produtividade de transporte para planejamento de curto prazo através da utilização de informações oriundas do banco de dados sistema de despacho e distância média de transporte oriunda da confecção dos planos de curto prazo, tomando como base os avanços de lavra e destinação dos materiais. A fim de chegar em um indicador da produtividade de transporte mais fiel aos resultados que de fato são praticados, foram levados em considerações os dados históricos mais recentes, obtidos por meio de um sistema de despacho e controle dos equipamentos (Dispatch®)... O trabalho proposto foi aplicado na mesma operação onde os dados foram obtidos e obteve resultados satisfatórios, possibilitando o acompanhamento mais detalhado da execução do plano de curto prazo e demonstrou-se passível de ser aplicado, também, para o planejamento de longo prazo. Os dados utilizados são provenientes de uma mina em operação (Cu-Au) situado no norte do Brasil.

Oct 30, 2017

By Flanelson Maciel Monteiro, Marcondes Mendes de Souza, Mauro Froes Meyer

This research is based on a bibliographical review of a field work that was done in the municipality of Parelhas / RN. The area explored, in turn, is known for its richness of mineral resources that are present in pegmatitic rocks. The general objective of this research is to characterize the main properties of the pegmatites and quartzite, in order to verify the heterogeneity of the elements, to raise a possible viability of extraction for economic purposes. The quartzite also presents a siliceous chemical composition. This rock is a source of bricks and silica refractories used in the steel industry and for the preparation of the blast furnace bed, ornamental rock used in different ways (rustic, carved, polished, among others). However, this research resulted in preliminary data, but it would be interesting to be more detailed in order to evaluate the economic viability of these rocks.

Oct 3, 2019

By Jefferson Monteiro Oliveira

A eficiência das turbinas a vapor de condensação é diretamente alterada pelo desempenho dos condensadores de superfície e estes últimos são negativamente afetados não somente pela entrada de ar no sistema, mas também por entupimentos e diminuições nos fluxos de água de refrigeração. Entretanto, qualquer uma das fontes de diminuição da eficiência do condensador geram efeitos similares dificultando a distinção entre elas ou a contribuição de cada uma para a queda no desempenho. Então a decisão pela manutenção tem aspectos claramente econômicos. Este artigo apresenta métodos para avaliação das fontes de perda de desempenho em condensadores e suas consequências na geração de energia.

Sep 25, 2017

By Luiz Peixoto, Andrea Falcon

There are a few ways to impact the capacity of a reciprocating compressor, by altering suction and discharge pressure and recirculation. By reducing the pressure drop in the section before the compressor it is possible to provide a higher suction pressure and subsequently achieve a higher compressor flow rate. The increase in the suction pressure while maintaining the discharge pressure reduced the demanded compressor Head. When considering oxygen compressors it is necessary to cautiously evaluate the safety norms and parameters due to the risk of explosions and fires due to high oxygen velocity.

Oct 3, 2019

By Márcio Lobato Genelhu

Este trabalho tem o objetivo de apresentar o modelo de recuperação refratária a quente dos regeneradores dos altos-fornos, através da técnica de solda cerâmica, visando o aumento da vida útil e evitando a parada prematura para a manutenção destes equipamentos. A aplicação da solda cerâmica prolongou a vida útil dos regeneradores.

Aug 8, 2018

By Armando Vazquez

Steel Dynamics Inc. (SDI) and Tenova Goodfellow Inc. (TGI) have successfully commissioned the first hybrid extractive/laser system for continuous and full spectrum analysis (CO, CO2, O2, H2 and H2O vapor) on two twin shell furnaces at Butler, Indiana. NextGen® technology using off-gas analysis as a main tool for EAF practice optimization is a proven effective method for improving plant productivity. Significant benefits attributed to the NextGen® system are operational cost reductions through the use of real-time dynamic control of chemical energy and improved environmental conditions through reduced GHG emissions. Additionally, the implementation of Tenova’s Water Leak Detection Technology® has shown results as an effective tool for operators to identify in real-time the presence of water during both reducing and oxidizing conditions. This paper will include project details, trials and results and will also outline the latest hardware developments and multipoint capabilities

Oct 30, 2017

By Ruy José Feijó Alves

O policarbonato é um polímero quimicamente neutro, 100% reciclável, resistente a altas temperaturas, impermeável, durável que oferece uma combinação fantástica das suas propriedades físicas, químicas, mecânicas, térmicas e eléctricas (isolante eléctrico). O policarbonato é um dos plásticos de maior venda e que mostra a maior taxa de crescimento anual no mundo, devido às suas excepcionais propriedades e versatilidade de aplicação e uso. Devido à grande utilização de polímeros nas mais diversas aplicações ao ar livre, surgiu a necessidade de estudar sua resistência às intempéries, não somente por aspectos estéticos, como descoloração ou perda de brilho, mas também por mudanças nas suas propriedades. Os polímeros quando expostos a luz solar na presença de oxigênio são degradados, no entanto as taxas de degradação foto-oxidativa dependem fortemente da natureza química do polímero. Durante o processo de degradação ocorrem mudanças físicas e químicas no polímero que levam à descoloração, fissuramento, perda de brilho e queda de resistência mecânica. Tais fenômenos estão quase sempre associados a processos de cisão de cadeia e, em alguns casos, ocorrem também reticulações. Para se avaliar a estabilidade, ou mesmo avaliar a eficiência de um polímero, é necessário submetê-los a ensaios que simulem as condições às quais ele estaria exposto durante a sua vida útil. Nesse contexto será apresentada uma avaliação sobre a degradação do polipropileno exposto a radiação ultravioleta.

Aug 8, 2018

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 Jaine Ana Ferreira

A GAL tem uma constante preocupação em desempenhar as atividades de embarque e faturamento de forma eficiente e ao mesmo tempo receber a produção cada vez melhor. Pensando nisso, a equipe buscou parâmetros que pudessem medir a eficiência do Entreposto13 e propor melhorias, visando eliminar as constantes paradas de equipamentos por falta de área de armazenagem no Entreposto. O desejo era reduzir a quantidade de bobinas removidas no momento do carregamento, pois quando se reduz esse o manuseio interno, reduz-se o tempo do embarque e consequentemente agiliza o recebimento de bobinas no entreposto. Várias outras melhorias de infraestruturas e gestão de pessoas e equipamentos foram necessárias para que o objetivo final fosse alcançado. Objetivo esse que se resume em reduzir paradas dos equipamentos de Preparação de Bobinas à Quente para aumentar a velocidade de embarque.

Aug 8, 2018

By Yong Tian, Tian Zhang, Zhao-Dong Wang

To meet the requirements of high-performance steel plates, while reducing manufacturing costs and saving energy, the advanced cooling system for plate mill (ADCOS-PM) with functions of accelerated cooling (ACC), ultra-fast cooling (UFC), and direct quenching (DQ) was researched and developed by the State Key Laboratory of Rolling and Automation (RAL). Since 2003, several sets of ADCOS-PM device were developed and implemented in industrial practice. To fully utilize the ADCOS-PM technology, the combination of various strengthening mechanisms was promoted by NG-TMCP technology and low-cost, high performance plates were produced such as pipeline steels, and high-strength construction machinery steel.

Oct 1, 2019

By Diego Berti Salvaro

The morphology, dimensions and chemical composition of tribolayers strongly depend on the pressures and temperatures acting on the contact. They are formed by reactions between the surfaces in contact with each other as well as with the atmosphere, lubricants and possible contaminants. In this paper the influence of test time (180, 500, 1000 and 2500 h) into the formation and characteristics of tribolayers in pairs DLC-stainless steel tested under refrigerant gas R134a atmosphere without presence of lubricating oil was analyzed. The characterization was performed using scanning electron microscopy, energy dispersive spectroscopy (SEM-EDS) (morphology and chemical composition) and white light interferometry (dimensions). The tribolayers thicknesses ranged from 100 to 500 nm and they were composed by elements originated from mutual transfers between the tribological pairs as well as oxides, being more pronounced on the stainless steel surface. The results show that the tribolayers are chemically stable (maintained the same composition over time) and the thickness remained stable after a thousand hours of testing.

Jul 31, 2018

By Jônatas Venancio Barbosa, Dagoberto Brandão Santos, Túlio Magno Füzessy de Melo

In this work, the mechanical and metallurgical behavior of titanium added ultra-low carbon (ULC-Ti) steel under hot and warm working conditions was studied by means of dilatometer compression tests. Double compression schedules were performed at temperatures between 700°C and 1000°C, inter-pass times of 0.5-100 s, and deformations of 0.5 and 0.3 in the first and second stages, respectively, with strain rate of 1 s-1. The analysis of the flow curves obtained allowed the evaluation of the softening characteristics of the steel. The softening and microstructure features indicate different restoration mechanisms depending on the temperature range. Static recrystallization with rapid microstructure restoration is observed at temperatures within the austenitic and intercritical field. Strain induced boundary motion and recovery mechanisms apparently control the restoration process in the ferrite region. In general, flow stress curves showed dynamic recovery behavior. Only the deformation in the intercritical region produced a peak in the flow stress curves. Isothermal holding tests associated with single hit compression indicated the presence of dynamic strain induced transformation, accelerating the softening kinetics at the intercritical region.

Oct 1, 2019

By Leandro Rigo Ramos, Marcelo Lucas Pereira Machado, Lumena Gloria de Souza Nunes, Mariana Valinhos Barcelos

The aim of this work was to study the influence of temperature on the grain refining process from severe plastic deformations through the simulation of Accumulative Roll Bonding (ARB) by torsion tests. The assays were performed to simulate the ARB at three different temperatures of 550 ° C, 625 ° C and 700 ° C with 5 torsion cycles with equivalent strain of 0.8 per cycle at a rate of 0.1−1 , totalizing an accumulated deformation of 4.0. Grain refining was obtained with an average size of 2μm, 5μm and 6μm for the temperatures of 550 ° C, 625 ° C and 700 ° C respectively. There was a rise in Vickers hardness by 68%, from 119HV in the annealed sample to 175HV in the deformed sample at 550 ° C. In the deformations at 625 ° C and 700 ° C the value of 130HV E and 150HV respectively was obtained. Based on the obtained results, it can be stated that the severe plastic deformations in microliged steel, carried out at temperatures lower than the end of the austenite-ferrite transformation, produce refined grains of the order of 2μm and, consequently, increase the mechanical strength of the material.

Oct 1, 2019

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 Luis Acainas Caballero, Karl Hoen, Stephan Krämer, Christoph Klein

The situation of the steel industry is still challenging. Worldwide overcapacities have an impact on profitability. More than ever, the point at SMS group is to provide the steel industry with flexible and profitable technologies and systems over the whole process chain. One example for that is the thin slab casting and rolling technology and, in particular the CSP® technology (Compact Strip Production), being well established for hot coil production. From its introduction in 1989, CSP® technology has been continuously further developed. Today, on a CSP® plant, the full range of high-quality steel grades can be produced with tightest geometrical and metallurgical tolerances under optimal economic conditions. With the introduction of semi-endless rolling and, as a further step, the endless rolling process, the product range for thin and ultra-thin products has been further enlarged, allowing for the production of hot rolled coils with a thickness of 0.8 mm for low carbon steel grades. Also high-strength steel grades may be produced with gauges below the minimum product thickness that can be achieved in a conventional-type hot rolling mill. Another step in the further development of CSP® technology is digitalization. In December 2016, the CSP® plant of Big River Steel (BRS), located in Arkansas, USA was put into operation. It is the first learning steel mill in the world. The CSP® plant of BRS comes with innovative technologies, providing impressive operational results right from the beginning.

Oct 1, 2019

By Emanuelle Garcia Reis, Gustavo de Sousa, Rodney Pardo Alves

Gerdau Ouro Branco´s plate mill started the operation in 2016 with high level technology. In general, national and international plate markets are every day more rigorous about final product quality. Suppliers must be aware about dimensional accuracy, surface quality and flatness of the plates, independent of the quality standards. To guarantee the best service to this increasingly demanding and competitive market, it is extremely important to guarantee the original project conditions executing the right maintenance of the rolling mill main components. In order to maintain the product quality and avoid the production and maintenance cost increase, it is important to find ways to control the mill and the main process variables, through daily measurements of the equipment performance. This paper aims to present the influence of the main equipment variables that affect the mill operational stability and how to control and evaluate the mill performance.

Oct 1, 2019

By Manfred Hackl, Sergey Bragin, Alois Seilinger

The demand for hot rolled strip is growing in multiple ways. To remain competitive, new and existing mills must meet arisen challenges in the best possible way. The production of hot strip is a key element of steel production. Since close to half of all steel produced is hot-rolled to strip, mills require maximum throughput and availability combined with geometrical precision and the ability to create optimum material properties. Today there is a clear trend in developing new steel grades with high-strength and improved formability, like 3rd generation AHSS (Advanced High Strength Steels), as well as a trend to produce thinner and wider gauges. This trend challenges hot strip mills because it requires new technologies which provide more flexibility in metallurgical treatment during the rolling process. In order to meet and promote these trends Primetals Technologies is currently working on different concepts and solutions. One example is the development of a new mill stand technology Flex-HI HOT which allows to adapt the last finishing mill stands by efficiently switching from 4-high to a 6-high mode with small work roll diameter based on production needs. Another solution is to apply a permanent 6-high rolling stand at the end of the finishing train. A smaller work roll diameter allows to achieve higher specific thickness reductions and deformation rates resulting in significant thinner hot-strip gauges with valuable metallurgical benefits. The developed solution concepts with technological and metallurgical benefits will be presented in this paper.

Oct 1, 2019