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By Baoliang Xiao, Hui Pan, Yajun Hui, Kun Liu

The microstructure, properties, strengthening mechanism and work hardening mechanism of 600MPa grade high ductility hot-rolled sheet steel for automotive square tube were investigated by utilizing optical microscopy, scanning electron microscopy and transmission electron microscopy. The results show that the microstructures of low C-low Mn-Nb and Ti microalloyed steel (Steel A) and high C-high Mn-Nb microalloyed steel (Steel B) are composed of ferrite and a small amount of pearlite. Compared with steel B, the size of ferrite and pearlite of steel A is finer, while the size of the second phase precipitates is larger. The mechanical properties of the two tested steels are similar before tube forming, except that the yield ratio of steel A is higher. Steel A has/exhibits significant work hardening after tube forming; the yield strength and tensile strength increase by 45 MPa and 26 MPa, respectively, while the elongation decrease by 6.0 percent. The yield strength and tensile strength of steel B increase by 22 MPa and 10 MPa, respectively, and the elongation decrease by 4.0 percent. The grain refinement strengthening is the dominant strengthening mechanism, accounting for 52.9 to 61.8 percent of the total yield strength; the solid solution strengthening is the second strengthening mechanism, accounting for 17.2 to 25.3 percent, while the precipitation strengthening and dislocation strengthening contribute little to the yield strength. The dislocation strengthening increase by 82 MPa of steel A after tube forming, which is higher than that of steel B. Therefore, steel B has a low work hardening rate that is more suitable for manufacturing automotive square tube for secondary tube forming.

Oct 1, 2019

By Francisco Morganti

The market requirements which strip processing lines have to deal with have altered significantly within the last decades. Particularly, the production has to be economical and ecological efficient and processing lines have to cover a broad product portfolio. Already existing plants either directly or indirectly are competing with new plants, which are equipped with the latest technologies. The “Special Strip Processing Equipment” is designed to be integrated easily and within small downtime phases in existing lines. All single machines can be delivered in short time “ready-to-perform” with a tested and proved automation system. Thus, the competitiveness of existing lines can be increased immediately with less effort. To find out which machines can be reasonably implemented SMS group offers an “Efficiency Check”. A special proceeding is used by experts to find out quickly which machines will have the largest effect on the efficiency of the line while demanding at the same time the smallest expense.

Aug 17, 2017

By Kermit Reins

The most recent modernization phase of the wire rod mill at Sterling Steel involved installation of a pre-finishing mill, using a Morgan Vee Mini-Block, a new water box and shear with utility systems and automation. The new mill configuration adds more stands to the mill for better drafting and is designed to improve finished product quality by providing a more uniform entry temperature, better control of the feed section into the No-Twist® mill as well as enhanced surface quality. The new shear improves cut length accuracy as well as decreases the amount of trimming to reduce yield loss. This paper explains the changes made in the mill and the features of the new equipment and automation.

Aug 17, 2017

By Luís Carlos da Silva

Atualmente, uma das principais preocupações da humanidade está relacionada à questões ambientais, que motivam pesquisas para o desenvolvimento de materiais com recursos renováveis e amigáveis com o meio ambiente. No entanto, este estudo pretende comparar, à resistência dos compósitos reforçados com fibras naturais, portanto, favoráveis ao meio ambiente e compósitos reforçados com fibras de vidro, que por sua vez têm impactos ambientais desde a fabricação até à disposição. Treze compósitos foram confeccionados para essa pesquisa, contendo 0% de fibra, 30% de fibras de curauá e 30% de fibras de vidro em matriz epóxi e testados em uma máquina de tração. Os resultados mostraram valores mais altos para as amostras reforçadas com fibras de vidro, no entanto, para relacionar a tensão do compósito com à sua densidade de fibra, verificou-se que os compósitos reforçados com fibras naturais apresentaram resultados melhores do que os produzidos com fibras de vidro. Concluindo, pelo ponto de vista da propriedade mecânica, as fibras de vidro podem ser substituídas pelas fibras de curauá.

Oct 30, 2017

By Gabriela Pereira de Miranda

Este estudo teve por objetivo avaliar a soldabilidade a pontos entre os aços 22MnB5 e Dual Phase da classe de 800 MPa de limite de resistência (DP800), ambos com 1,8 mm de espessura. A intenção foi determinar os parâmetros adequados de soldagem para esse tipo de junta soldada, que vem sendo progressivamente utilizada na estrutura de veículos automotores, em virtude do uso crescente de peças fabricadas a partir do aço 22MnB5, submetido ao processo de estampagem a quente (hot stamping). Foram avaliadas as propriedades mecânicas através de ensaios estáticos de cisalhamento e de tração cruzada, em juntas soldadas produzidas a partir da variação do tempo de soldagem e da força aplicada pelos eletrodos. Percebeu-se que as juntas confeccionadas com o tempo de soldagem com múltiplos pulsos (9/2/9/2/9 ciclos) e a força de 5,0 kN obtiveram os melhores resultados em cisalhamento. Em contrapartida, os corpos de prova produzidos com a força de 6,5 kN atingiram os maiores valores em tração cruzada. Independentemente dos parâmetros aplicados, todas as condições avaliadas permitiram alcançar o valor mínimo de carga de ruptura necessária para garantir a qualidade de uma junta soldada a ponto entre os aços avaliados.

Aug 16, 2017

By André Oliveira

The present paper describes state-of-the-art Pulverized Coal Injection technology with focus to Dynamic Distribution guaranteeing highest accuracy on equal distribution and being thus one of the key factors enabling constantly highest injection rates. As an alternative to the construction of a new plant, existing plants may be modernized and upgraded to latest technology. Two recent examples are presented. As a conclusion, two case studies of return on investment are showing that the PCI technology, both for new facilities as well as for upgrades, is very profitable and mandatory for high blast furnace operation effectiveness.

Aug 17, 2017

By Patrícia Freitas Rodrigues

Um comparativo entre dois métodos para determinação das temperaturas de transformação de fase, tendo como base análises de Calorimetria Diferencial de Varredura (DSC) em amostras de uma liga de NiTi equiatômica submetida a tratamentos térmicos para envelhecimento, foram utilizados neste trabalho. Sendo aplicado o método clássico comumente utilizado para análise desses resultados e o método utilizando da integral do pico de transformação de fase. Com base nas avaliações feitas, o método de integral por apresentar uma relação direta da fração de transformação demonstra-se mais eficaz para determinar o início e o fim da transformação por levar em consideração a forma do pico em função da trajetória de transformação.

Aug 8, 2018

By Jeremy Fletcher

In today’s world, the requirement of Steel Producers to revamp and modernize their blast furnaces on-time, safely and with the latest technology is paramount. In addition they must meet the detailed design, construction and safety legislation and regulations, which can be different for the various countries around the world. Siemens MT is renowned for its ability to perform Blast Furnace rebuilds, relines and modernisations within extremely tight time frames and in a safe manner. Modular Blast Furnace construction concepts have been perfected to minimise project duration and plant downtime for furnace rebuilds. Safety and certainty are the keys for success. Siemens MT are constantly introducing new technologies into the market place including cyclone gas cleaning and triple external cone gas scrubber, along with step changes in technology such as dry gas cleaning and dry slag granulation. The economic environment and the continuing requirement for improved environmental performance, drive many of these innovations. This paper describes some of the latest rebuild reference projects of Siemens MT, along with the latest technical innovations installed on these furnaces, and some of the construction methodology used for a safe and secure rebuild.

Aug 1, 2018

By Juan Garcia de Blas

O presente trabalho aborda o desenvolvimento de liga titânio-nióbio obtida por metalurgia do pó no qual foi introduzida uma operação de extrusão angular em canal (Equal Channel Angular Pressing - ECAP) com o propósito de promover uma consolidação que favorecesse a homogeneização na etapa posterior de sinterização. Após o processamento o material foi caracterizado por microscopia ótica e microscopia eletrônica de varredura (MEV/EDS). Os resultados preliminares indicaram a importância da redução do tamanho das partículas de nióbio.

Aug 17, 2017

By Gabriel Burlandy Mota de Melo

Manchas de óleo em um meio aquoso foram removidas utilizando compósitos de parafina com nanopartículas de ferritas de cobalto (CoFe2O4), níquel (NiFe2O4) e níquel-zinco (Ni0,7Zn0,3Fe2O4), nas proporções de 13,0% e 28,5% em peso. Para avaliar a eficiência da remoção, foi determinada a velocidade dos compósitos ao serem acoplados a uma mancha de óleo na superfície da água e submetidos ao campo magnético de um imã permanente. O melhor desempenho foi obtido com o compósito de parafina contendo 13,0% em peso de ferrita de níquel-zinco.

Aug 16, 2017

By Mateus Luiz Gamba

O titânio e suas ligas são aplicados em grande escala em implantes ósseos por apresentarem excelentes resultados de biocompatibilidade. No entanto, ainda não existe um consenso na literatura com relação à influência das características morfológicas destes implantes na osseointegração, principalmente na definição da melhor rugosidade e energia superficial. Vários trabalhos têm sido realizados com o intuito de comparar diferentes tratamentos superficiais empregados para otimizar a adesão, o crescimento e a proliferação celular. O presente trabalho tem como objetivo apresentar uma base de dados sobre características superfícies versus osseointegração para experimentos de biocompatibilidade realizados in vitro. Foram feitas coletas e análise de dados qualitativos usando métodos analíticos em artigos científicos publicados em periódicos internacionais, sendo considerados na pesquisa artigos que utilizaram superfícies de Ti/TiO2 e células osteoblásticas. Os principais atributos definidos para a base de dados foram rugosidade, tamanho da célula, energia da superfície e/ou ângulo de contato, tipo de tratamento superficial, viabilidade e a resposta observada na cultura celular. Espera-se que esse artigo contribua para que futuros trabalhos possam utilizar métodos e estudos que permitam auxiliar na descoberta de conhecimento através de padrões que acelerem o processo de osseointegração impactando diretamente na recuperação do paciente implantado e na sua qualidade de vida.

Aug 8, 2018

By Ádria Rocha Corrêa

Durante a solidificação de ligas metálicas, o produto fundido se contrai, o qual provoca o surgimento de espaçamentos vazios na interface metal/molde chamados de “gaps”. Estes gaps causam o aumento da resistência térmica influenciando em toda a cinética da solidificação. A transferência de calor durante a solidificação depende do conhecido parâmetro chamado de coeficiente global de transferência de calor ( hg). Este parâmetro é representado pela equação do tipo: hg =C.t-n, a qual indica que a eficiência térmica na interface metal/molde decai com o tempo. Muitos parâmetros podem influenciar o coeficiente global de transferência de calor (hg), neste estudo, os percentuais de Sn em ligas do sistema Al-Sn são analisados (10,20,30 e 40%Sn). Portanto, o principal objetivo deste estudo é propor uma relação matemática que descreva, para o sistema Al-Sn, a evolução hg em função do teor de Sn. A relação matemática foi obtida através do método dos mínimos quadrados

Aug 17, 2017

By Stefano Scubla

DANIELI Q-MELT is the latest evolution of EAF concept to automatically control each stage of the melting process, from the electric power planning to the combustion optimization as well as the slag and steel metallurgy management for every operation required in the EAF cycle. The core of the automation system is the Melt-Model that automatically identifies deviations of the process control variables and corrects them to avoid losses or wasting of available energy sources. The real-time online off-gas analysis, via the in-situ laser system, promotes the process tracking and permits further optimization by a viable closed-loop control acting on fuel and oxygen postcombustion. A suite of supplementary stand-alone Technological Packages integrates the Q-MELT to further maximize the productive time and the utilization factor, supporting the operators to limit downtimes, avoiding misoperations and/or mistakes.

Aug 16, 2017

By José Adilson de Castro

In this paper a new technology for a compact iron ore sintering machine is analyzed. The compact sintering process is based on the massive injection of gaseous fuels and the solid fuel is only agglomerated fine charcoal obtained by biomass. The solid fuel used in this study is obtained by agglomeration of fine charcoal produced from elephant glass which has very short period for production and CO2 capture(less than 6 months in tropical climate). To overcome the lower heat supply into the combustion front of the sintering process the simultaneous injection of oxygen and gaseous fuel is proposed. The proposed methodology is to combine the solid fuel (agglomerated fines charcoal) and steelworks gases in a compact machine to enhance heat and mass transfer with high productivity (about 5 times the conventional large machine). A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction rates and phase transformations is used to analyze the inner process parameters. A base case representing a possible actual industrial operation of the sintering machine is used in order to compare different scenarios of practicable operations which represents advanced operations techniques. The model was used to predict six cases of combined operation with biomass and fuel gas utilization with oxygen support.

Aug 2, 2018

By Liao Jianfeng

The Baosteel Zhanjiang 5,050m3 blast furnaces have been built with highly independent integration and innovation technologies and represented the state of the art of the world’s huge BFs. The proper of BF1 and BF2 is designed with long-campaign technology; both BFs share the same set of stockhouse, water and PCI systems; the BCQS serial-hopper no-bell top, TRT and blower are all local equipment as applied; four top-combustion stoves systems are matched; the BFG is cleaned by fully dry process; and the automation control system for the main process is self integrated. The BFs have been started up and performing with sound indicators. Their smooth proceedings symbolize China’s huge blast furnace ironmaking technology ascending a new high.

Oct 30, 2017

By Patrick E. Connell

During the ABM Conference of 2015 the latest design and process features of the new 3-roll RSB® generation were presented together with a unique Size Control System SCS® for a real time closed loop control to produce an extraordinary quality SBQ – day in, day out. In the past two years, Kocks has focused on improving the repeatability of the rolling process and developed technology to enhance the performance of its equipment. These developments include Fast Remote Control (FRC), Stands Adjustable Under Load (AUL) implementation of closed loop Size Control System (SCS), and finally a state of the art laser Gauge (4D Eagle) that pulls all of these developments into a complete package of quality. Gauges used in the past generally operated with the “shadow” measuring system. The latest gauge developments are based on the “light section” method. This method is more suitable to provide real time measurement parameters of the rolled bar. Placed close to the last rolling stand, the “light section” gauge is capable of measuring around the complete diameter with a clear definition of the bar stage in relation to the axes of the rolls. It is also capable of making these measurements using a very high measurement frequency. Following requirements of the market, requiring the highest gauge measuring frequencies which display the bar in the most accurate way even at the highest rolling speeds, the “4D Eagle” gauge was developed. This paper describes all the process features and parameters of this impressive and unique newly developed gauge as well as the other described technical improvements.

Oct 30, 2017

By Jorge Madias

Se analizan las distintas alternativas para la producción de barras de refuerzo de hormigón: endurecimiento por solución sólida (“dureza natural”); endurecimiento por temple y autorevenido en línea (Tempcore, Thermex, etc.) y endurecimiento por precipitación (microaleación con niobio, vanadio o titanio) y su influencia sobre la performance de las barras, en lo que hace a la resistencia a la corrosión, al fuego y a los sismos.

Aug 17, 2017

By Sunil Katharia

In February 2016, the upgraded Blast Furnace 1 of JSW Steel Limited (JSW) at its Vijayanagar Steel Plant was blown in after a 6 months shutdown in which the whole furnace was rebuilt on the existing foundation and within the existing tower structure. Despite several plant constraints it was possible to increase the furnace inner volume by 85% - reaching 2307 m3 from existing 1250m3. The upgradation project covered the stockhouse and its dedusting system, top charging system, furnace profile, furnace cooling system, casthouse and its dedusting system, slag granulation plant, pulverized coal injection plant, hot blast system and gas cleaning plant – with major interventions in order to cope up with the changed operating conditions. The total scope of the project was split by JSW into several packages, all based on design data provided by Paul Wurth. JSW was responsible for coordinating the local subcontractors along with Paul Wurth which has been appointed as main technology supplier in charge of complete basic and selected detail engineering in the key areas and of the supply of core equipment such as the Bell-less Top®, copper staves, GCP key items and TMT casthouse machines. The main design concept and the key points of the project such as optimization of project ROI, advanced erection concepts as well as a summary of the operating results are presented confirming JSW “BF1” upgradation as one latest examples of the current state of the art in the revamping projects.

Aug 17, 2017

By Herrmann Flor

In steelmaking process, where up to 70% of variable cost of finished product is already incurred, energy and refractory costs account for 45-50% of the cost of production of crude steel and contribute significantly to the carbon footprint of the end product. Any attempt to control and reduce these costs will automatically lead to more competiveness and reduced carbon emissions. Leading the technology for ECOPLANT (characterized by the fact that the economic and ecological benefits are integral part of our products), SMS has developed innovative solutions which can be applied to both new and existing plants alike. This paper reviews one of the electrical and automation concepts. Tackling the secondary gas cleaning system and hence being applicable to almost all steel plants, the X-Pact® Gas Cleaning Assistant optimizes the control of individual dampers based on modelling of fluid resistances of ductwork in gas cleaning system. It guarantees the best dust removal from work place at minimum energy consumption.

Oct 30, 2017

By Andrea Zanon

Recently steel manufacturers have significantly focused their attention on safety and working conditions thanks to new labour laws, comprehensive operators’ knowledge and increased company social responsibility. Even with a reduced budget, investments on safety are now widely approved. Mill constructors aim at developing upgraded solutions to comply with these new requirements. In some cases mill constructors can even anticipate customers’ requests and consequently put into the market innovative solutions. In this text we will analyze some advanced solutions developed by Danieli & C. Officine Meccaniche Spa - the leading company in long-product rolling mills - aimed at improving working conditions on wire-rod block settings. In particular, we will focus on rolling guides installed on fast-finishing blocks and on servo-assisted device for rolling rings changing. In fact, this equipment has shown effective benefits on our test plants and has mainly cut out the tendency of the personnel to be absent due to backache. This paper will first present standard working conditions, will then introduce the newest equipment developed by Danieli & C. Officine Meccaniche Spa, will analyze its operation and finally will describe in detail the benefits that can be reached with its use.

Jul 30, 2018