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By Davidson Marcos de Oliveira, Antonio Adel dos Santos, Vicente Tadeu Buono

The benefits of using the controlled rolling process followed by accelerated cooling (TMCP), currently used in the main rolling mills in the world are already well known and metallurgically based. The need to obtain mechanical properties with a high degree of homogeneity means that in some situations the ends of the rolled material are discarded, negatively affecting the metallic yield of the process. Therefore, this work focused on the determination of the mechanical properties variation at the ends of thick plates processed by TMCP of steels for application in oil and gas pipelines, in order to map the extent of these differences and to correlate them with the microstructure obtained, the profiles of temperature and cooling rates in these regions. To perform the work, two slabs of the studied material were rolled, and the temperature profile was recorded along the plate in the controlled rolling and accelerated cooling processes. The ends of the material were sampled in sections at every 100 mm and subjected to tensile test, hardness and the Charpy V-notch impact test, as well as dilatometry and microstructure evaluations. For the used process conditions, the results indicated the formation of a banded microstructure, basically consisting of polygonal ferrite and bainite, occasionally containing small fractions of perlite. The mechanical properties in the top and the base were higher than the values found in the plate middle, justified by the microstructure found. The work allowed understanding the relationship between the mechanical properties, microstructures and process conditions at the ends, helping the team to improve the process in order to result in a high degree of homogeneity of the product and, thus, lead to optimization of the metallic yield.

Oct 1, 2019

By Masakazu Iida

In this article, technologies of unburned Al2O3-MgO (UAM) refractories are demonstrated in terms of microstructure evolution. During operation, Mg2+ diffuses from MgO to Al2O3 through the liquid phase to form spinel (MgAl2O4) network. Molten slag tends to penetrate along the voids in the spinel network structure and spinel dissolves in the penetrated slag. Therefore, maintaining a high degree of spinel saturation in the penetrated molten slag is important. In order to achieve the condition described above, suppression of overall mass transfer through penetrated slag is effective. This is achievable by evolution of complicated spinel network structure with small pore diameter, which increases the flow resistance of molten slag. Thus, optimization of refractory composition and fabricating conditions, with the aim of creating on improved spinel network, is essential. The effectiveness of spinel network improvement was validated by commercial applications. According to the investigation of UAM brick after use, further densification due to heating under restrained conditions was recognized. Hence, it was concluded that the evolution of the spinel network structure in UAM refractories is essential technology needed to improve durability.

Oct 30, 2017

By Leonardo Camilo dos Reis, Edmilson Fernandes Dadomi, Claudio Silva de Paulo

In the hot strip mill production, one of the factors that may affect the productivity is the occurrence of failure due to the geometry of the strip at the exit of the rolling mill, because the tip of the strip can turn-down or turn-up. This study had the objective of evaluating the behavior of the strip when leaving the working rolls, through numerical simulation, aiming to know the influences of the main variables that govern the formation of the turn-down. The methodology consisted in performing the computational simulation of the strip mill and to vary the operational and geometric parameters that could influence the process. The results showed that the rolling of hot strips of HSLA material with final thickness varying between of 3 to 6 mm and a reduction of 6.6% to 11.0% in the last stand of a hot strip mill, tends to bend towards the roll with larger diameter, higher friction coefficient , higher temperature and lower limit of material flow. It was observed that the variation in diameter is the main factor that contributes to the formation of the curvature of the front-end of strip. Based on these results, several measures were implemented in the industrial line, with a significant reduction in the occurrence of turn-down.

Oct 2, 2019

By Tiago Ribeiro Costa

A Praxair é uma das três maiores empresas de gases industriais do mundo, com atuação em mais de 40 países e fortemente atuante na indústria siderúrgica. A Praxair possui experiência para fornecer produtos e serviços para todos os tipos de siderúrgica. Diversas tecnologias desenvolvidas pela Empresa, como o CoJet® (sistema para injeção de jato coerente de oxigênio em fornos elétricos e conversores), Slag Splashing (espalhamento de escória nas paredes de conversores, aumentando a vida útil dos refratários), AOD (processo para produção de aços especiais) e outros, encontram-se em operação comercial atualmente em diferentes partes do mundo. No Brasil, a PRAXAIR é a controladora da White Martins, maior empresa de gases industriais da América do Sul, presente em nove países do continente. Seu portfólio inclui gases atmosféricos, produção de gás carbônico, acetileno, hidrogênio, gases especiais e medicinais, misturas para soldagem, cilindros de aço sem costura, equipamentos para aplicação, transporte e armazenamento de gases. A empresa também opera uma unidade para liquefação de gás natural. Além de tecnologias e processos, a White Martins também pode fornecer soluções e equipamentos para medição, controle e injeção de gases, atendendo às rígidas normas de segurança e padrões de qualidade. O Objetivo deste trabalho é apresentar e discutir sobre a solução para o fornecimento de mistura para atmosfera de fornos de tratamento térmico através de um painel misturador de gases hidrogênio e nitrogênio. Será discutida a operação do equipamento e abordadas às características construtivas.

Jul 31, 2018

By Lucas Gonçalves Generoso, Larissa Rodrigues de Carvalho Rocha, Gerson Evaristo de Paula Júnior, Beatriz Fausta Gandra

A eficiência na redução dos minérios de ferro no alto-forno é governada pela estrutura e permeabilidade das camadas de carga. A zona granular do alto-forno é a região onde a carga mantém a sua estrutura estratificada, decorrente do carregamento, sob a forma de grãos sólidos. Nessa região, as condições de permeabilidade determinam o perfil de distribuição do gás e, consequentemente, a eficiência térmica e química do reator. Na Usiminas, foi desenvolvido um ensaio de permeabilidade que permite avaliar a perda de carga em leitos formados pelas matérias-primas utilizadas nos altos-fornos, buscando as condições mais favoráveis ao fluxo gasoso. A partir deste ensaio, foi possível avaliar cargas compostas exclusivamente por sínter, pelota ou minério granulado, ou ainda combinações binárias entre estes. O sínter apresentou a maior perda de carga, seguido da pelota e do minério granulado. Apesar disso, o sínter foi o material que permitiu maior acréscimo de vazão do gás. Os ensaios realizados indicaram que 5% de material com granulometria menor que 5 mm é o limite para a concentração de finos do sínter, situação em que foi observado acréscimo de aproximadamente 50% na resistência à passagem dos gases para as velocidades correspondentes àquelas dos altos-fornos. O leito de melhor permeabilidade foi formado por 95% de sínter e 5% de pelota, seguido pelo de 100% de sínter, sem diferença significativa entre essas condições. Em geral, a combinação de sínter e pelota é mais benéfica para a permeabilidade do leito.

Oct 1, 2019

By Edgard de Macedo Silva

Aços inoxidáveis duplex apresentam boas propriedades mecânicas e de resistência à corrosão, mas quando são colocados para trabalhar em altas temperaturas como no processo de soldagem e de tratamento térmico ocorre o surgimento de fases que comprometem as suas propriedades. Dentre elas, a fase sigma (s) é a que apresenta um maior efeito de fragilização por ser rica em cromo e empobrecer a matriz desse elemento, bem como por apresentar dureza em torno de 1000HV. No presente trabalho, uma metodologia não destrutiva, baseada na interação entre densidade de linhas de campo e um aço inoxidável duplex, é apresentada para o acompanhamento da formação da fase s na temperatura de 800°C em um aço envelhecido por até 2 horas. Diferentes intensidades de campo foram geradas por um eletroímã e o fluxo de linhas de campo foi aplicado no material de estudo. A densidade de linhas de campo resultante foi medida por um sensor de efeito Hall. Os resultados foram correlacionados com resultados de microscopia eletrônica de varredura (MEV), dureza e difração de raios-X (DRX) e mostraram que os valores de tensão hall reduziram à medida que a fração volumétrica da fase s aumentou. A formação dessa fase não magnética influenciou no sinal obtido pelo sensor Hall. Existiu uma correlação entre a densidade de linhas de campo resultante e a presença da fase fragilizante, apontando para uma metodologia capaz de acompanhar a formação dessa fase.

Aug 8, 2018

By Luiz Flávio Pereira Costa

O espessamento de lamas no processo de beneficiamento de minério de ferro é de fundamental importância para a recuperação de água de processo, pois 75% da água é recuperada nesta etapa. Além disso, a qualidade da mesma interfere diretamente no bom desempenho das demais etapas do processo, principalmente na etapa de flotação. Vários são os parâmetros que interferem para obtenção da clarificação ideal do overflow, como: pH, dosagem de coagulantes e floculantes, percentagem de sólidos na alimentação, etc. O pH pode ser considerado o mais importante, pois a partir dele é que se determina as dosagens de coagulante e floculante referentes ao ponto ótimo de coagulação reduzindo assim os efeitos negativos na etapa de flotação. O teste de sedimentação em proveta é uma forma simples e rápida de realizar uma análise da velocidade de sedimentação e clarificação da água frente a diferentes combinações dos parâmetros citados. A Samarco resgatou e implementou na rotina dos operadores da área de espessamento a realização de testes de sedimentação em proveta com o objetivo de reduzir o tempo decorrente de coleta de material, envio ao laboratório e espera pelos resultados. Após a implementação dos testes na rotina operacional, observou-se motivação da equipe em redução de custos, embasamento teórico e assertividade na tomada de ações, diminuição de incidência de eventos de má clarificação da água overflow e diminuição do consumo de floculante em cerca de 30%.

Aug 16, 2017

By Kazuya Nakabo

In this article, influences of restraint and MgO content on densification of alumina-magnesia castable during heating were experimentally studied. High thermal expansion-alumina-magnesia castable specimens were surrounded by low thermal expansion-alumina-silica castables, and heated in an electric furnace. Doing so allows restrained heating of alumina-magnesia castable. According to the results of simple calculations, the restraint stresses were estimated to be between 2 to 20 MPa, so the experimental conditions were considered reasonable. As a result of the experiments, it was verified that restraint densifies alumina-magnesia castable, resulting in an increase in modulus of rupture and modulus of elasticity. The densification effect of restraint became larger as the MgO content increased. The effects are attributable to an in-situ spinel forming reaction, which improves corrosion resistance.Taking the temperature distribution in the castable lining into account, large restraint stress is expected for the hot face while only a little effect is expected for back end. Thus, excessive difference in material property in the thickness direction, which is undesirable in terms of structural spalling, is a concern.Hence, the MgO content of alumina-magnesia castable should be determined carefully, taking not only corrosion resistance but also spalling resistance into consideration.

Oct 30, 2017

By Fábio Dian Murari, Antônio Adel dos Santos

The effect of reheating temperature of slabs on the precipitates dissolution and mechanical properties of Ti-Nb microalloyed steel was investigated in pilot scale. It was verified, by means of transmission electron microscopy, a significant decrease in precipitates formed during the solidification of the steel as the reheating temperature increased from 1100°C to 1200°C. No significant changes in size and shape of the precipitates were observed with further temperature increase up to 1280°C. In line with the precipitates dissolution behavior, an increase in strength was observed with the elevation of the reheating temperature up to 1200°C, due in part to the reprecipitation of fine Nb-rich precipitates during the hot rolling. At 1200°C the presence of deformed ferrite on the microstructure contributed to the additional increase in strength. After reheating above 1200°C up to 1280°C, a decrease in strength of the rolled plates was noticed. This effect has been credited to the absence of deformed ferrite grains and also to a small increase in the low angle grain boundaries size. The results were in agreement with Thermo-Calc and Dictra simulations.

Oct 1, 2019

By Ernesto Gustavo Maffia

En la actualidad, el moldeo por inyección es una tecnología muy utilizada en el procesamiento del plástico pues permite fabricar formas geométricas complejas. Para fabricar los moldes se utiliza ampliamente la aleación C17200 (Cu-2%Be), pero están en desarrollo algunas alternativas con aleaciones base cobre libres de berilio, que tienen valores de dureza por encima de los 30 Rockwell C y buena conductividad. Las aleaciones base de cobre, tipo CuNiSiCr son las más adecuadas como reemplazo. El siguiente trabajo trata del estudio y desarrollo del proceso de fabricación, por fusión, colado y conformado, de una aleación tipo CuNiSiCr de alta dureza y buena conductividad para ser utilizada en la fabricación de moldes de inyección para la industria del plástico. Los resultados preliminares de esta investigación demuestran que a través del aumento sistemático en el contenido de níquel y silicio se consigue un aumento de la dureza (>32 Rockwell C) y una aceptable conductividad eléctrica (˜25%IACS). El fenómeno segregación interfiere fuertemente en los tratamientos termomecánicos, pues se forma una segunda fase interdendrítica, de características frágiles, que genera fracturas en el conformado. Los resultados demuestran que la aplicación del recocido total y control de la temperatura durante la forja minimizan este problema.

Aug 7, 2018

By Christiano Gianesi Bastos Andrade

Clays with high content of smectite are denominated bentonites, and are widely used in industry as, for example, agents for bleaching of vegetable oils, animals and minerals. For this use, the smectite clays are treated with inorganic acid of high concentration at temperatures under boiling point, which provide the bentonite´s bleaching power. In the present study, a sample of smectite from Cubati, Paraiba, Brazil, was submitted to treatment under moderate conditions (90°C, reaction times of 1, 6, 12, 18 and 24hours in close reactor, concentration of the aqueous solution of hydrochloric acid 1.5 M, acid solution/clay ratio of 1g/10mL), aiming to reduce impurities, responsible for the color of the clay, without causing significant changes in their structure. Thus, clay can be used in the cosmetics industry and other products with high added value. The treated clay was characterized by scanning electron microscopy (SEM), stereomicroscopy, energy dispersive X-ray detector (EDS) and X-ray diffraction (XRD). It was observed a bleaching in samples with time of 12h to 18h. With the DRX was possible to monitor the peak intensity of the clay structure and the sample with 12 hours of treatment was not significantly altered its crystalline structure, maintaining the peak clay at d001. The most pronounced changes in the bleaching occurred within the first 12 hours of acid treatment.

Aug 8, 2018

By Beatriz Pereda, Ana Clara Fonseca da Silva, Tiago Seixas Bittencourt

Reinforcing steel bars are usually specified based on mechanical properties with flexibility in chemical composition and processing. Most developments, in these steels, are normally focused on alloy and process design to reach minimum cost and conformity to specification. Processing routes using quenching and self-tempering (QST) and accelerated cooling are the most common. Microalloying with V and Nb have been used in rebar. When acicular constituents must be avoided, a combination of Nb microalloying with judicious control of cooling is one of the preferred options. Niobium can contribute to improvement in tensile properties through austenitic grain size control during hot working, precipitation hardening due to carbonitrides or clusters, and hardenability increase. In the present work the alloy design and development processes of a Nb microalloyed steel for rebars are presented. The designed steel has fulfilled the required specification and is under regular production. Austenitic grain size refining – when comparing with the “basic composition” normally used was observed, even without any change in the thermomechanical processing cycle. There are indications that precipitation hardening may also occur. Results indicate that Nb is a good alternative as a microalloying element in rebars.

Oct 1, 2019

By Martin Chabicovsky, Milan Hnizdil

Emulsions are frequently used for the cooling and lubrication of working rolls during the cold rolling. The fact that the lubrication and cooling are not separable makes the optimization of both functionalities difficult. The higher emulsion temperature decreases the cooling efficiency compared to cold water. Heat transfer and fluid flow laboratory (Czech Republic), CRM (Belgium), Tata steel (Netherlands) and Henkel (Germany) cooperated on the increasing of a cooling efficiency during cold rolling. Part of this research was focused on an influence of the emulsion composition on a cooling intensity. The cooling efficiency was laboratory investigated. The stainless steel sample with thermocouple was heated and then it was cooled by a nozzle. Tests were performed with various emulsions and pure water. The heat transfer coefficient was computed from measured temperatures. The cooling intensity (heat transfer coefficient) of all tested emulsions was similar but an increase of the cooling intensity was found with water. Further various emulsions concentrations were tested. Results showed decreasing cooling intensity with increasing oil concentration. Adding additives therefore is thought to cause a noticeable decrease of the cooling intensity.

Oct 1, 2019

By Daniel Antonio Kapper Fabricio

A avaliação das propriedades de mecânica da fratura dos materiais é uma necessidade crescente, sobretudo no setor de óleo e gás. Esse cenário exige a garantia da qualidade na execução de ensaios de tenacidade à fratura. Esse trabalho tem como objetivo realizar uma comparação intralaboratorial para o ensaio de tenacidade à fratura KIC variando o executante do ensaio, visando atender ao requisito de garantia da qualidade da norma NBR ISO/IEC 17025. Os resultados foram comparados através de análise de variância. As diferenças entre os operadores não foram significativas frente ao erro residual a um nível de confiança de 95%, sendo tal resultado considerado satisfatório.

Aug 16, 2017

By Marcus Weldon

We are at the beginning of an era of profound transformation and human progress — a new industrial revolution. This “Automation of Everything” era will be brought about by digital interfaces, data analysis and control of the physical world through networks employing the Nokia Bell Labs Future X1 architecture — networks to support the digitization and connection of everything and everyone with the goal of automating much of life. The interconnection of robots, machines, drones, sensors, processing platforms and people through Future X networks will provide transformative tools for the automation and optimization of factories and warehouses, ports, electric grids, transportation networks, food, healthcare, construction, logistics and supply chain, emergency response, mining, and other physical industries. To date, the level of automation has been modest at best. Automating these physical industries — industries that account for 70 percent of the US Gross Domestic Product, for example — has the potential to drive significant increases in the world’s economic productivity.2 Realizing the potential of this next industrial revolution will require billions of wirelessly connected endpoints for high fidelity physical-to-digital conversion, millisecond response times to tightly control and coordinate machines and robots, and intelligent analysis to optimize real-time decisions — tasks beyond the reach of current networks. Increased levels of automation are already being achieved through the use of 4G advanced wireless access technologies. The untethering of sensors and actuators in industrial environments through the low-latency, high-bandwidth, high-reliability, and massive scale provided by 5G wireless access will complete this evolution, providing an unprecedented ability to digitize, analyze, comprehend and manipulate the physical world at a scale never previously thought possible. These new capabilities will enable us to create digital models of the physical world with ever higher levels of fidelity, further enhancing our ability to improve operational efficiencies and increase productivity and worker safety. Doing this will require a dramatic evolution in network architecture toward massively distributed cloud control and baseband capacity to achieve the required ultra-low latency and ultra-high bandwidth for industrial and infrastructure automation services — the Future X architecture. In early 2019, Nokia Bell Labs will publish a sequel to “The Future X Network: A Bell Labs Perspective”. “Future X for Industries: A Nokia Bell Labs Perspective” will explore how the Future X architecture will automate many of the world’s physical industries, including chapters devoted to electric power, cities, rail, mining, public safety, manufacturing, ports, logistics and supply chain, and an overarching chapter devoted to securing this highly automated world. To give you a small taste of the feast that’s to come, we’re sharing with you an initial installment — “Future X for Industries: Mining” — the Nokia Bell Labs view of how mining will be transformed through a Future X architecture..

Oct 1, 2019

By Martin Dirks

Nowadays the sinter cooler often becomes the bottleneck of the sinter production, with outdated equipment leading to low productivity and high operation and maintenance costs. Furthermore valuable energy is simply destroyed in the cooler, which is not compatible anymore with a cost efficient and environmentally friendly sinter production. Paul Wurth has developed and improved two types of coolers, the annular cooler and the shaft cooler which offer flexible solutions to the specific situation of each client. The classic design of the annular cooler was completely revised and is now composed of a rigid ringframe construction as opposed to the traditional design with individual sintering cars, avoiding the typical problems of centering. Additional features of the PW annular cooler are the low air leakage rate and the increased effective cooling surface due to the removal of dead areas. This leads, in addition to the lower weight, to lower operating costs and a smaller space requirement. The shaft cooler stands out with an even smaller space requirement and a lower sinter outlet temperature because of a very long residence time of the sinter inside the shaft. Its development into a pure counter flow cooler aims at maximizing its energy efficiency, as it is designed as a system with a very low demand for cooling air, high air discharge temperatures and highly reduced dust emissions. For both cooler types flexible heat recovery solutions can be offered. These solutions include the supply of hot combustion air to the ignition hood burners and the sinter strand, the production of steam for the clients steam grid or the production of electric energy.

Aug 16, 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 Daniela Mota Paschoal Veloso da Silva, Gabriel Filinkoski, Suelen Silva Rocha, Jorge Luiz Valença Mariz

A previsão da fragmentação da rocha é essencial para otimizar a operação de desmonte de rochas. A fragmentação depende de muitos parâmetros, como propriedades estruturais e geomecânicas do maciço rochoso, geometria do plano de fogo das detonações e propriedades dos explosivos. Neste contexto, este trabalho objetivou realizar a previsão da fragmentação por simulação do desmonte de rochas da Mineração Megaípe considerando as características estruturais e geomecânicas inerentes à formação do maciço rochoso através da metodologia de Kuz-Ram. A metodologia consistiu no levantamento das propriedades geométricas das descontinuidades visíveis na face da bancada existente, realização da classificação geomecânica através dos sistemas Rock Mass Rating (RMR) e Q e aplicação dos resultados para predição da distribuição granulométrica da fragmentação. Obteve-se como resultado da simulação que cerca de 90% do material fragmentado deve passar na abertura do britador primário disponível na pedreira, além de resultados favoráveis quanto às análises de condições de estabilidade do talude operacional.

Oct 3, 2019

By Horacio Destaillat

Desde hace aproximadamente 15 años se encontró por experiencia empírica que se puede “neutralizar” el efecto del plomo sobre la maleabilidad en caliente de cobre proveniente de la refinación térmica de chatarras mediante control de la composición química. Este hallazgo ha resultado de aplicación industrial. Si bien el contenido porcentual de plomo se reduce por refinación convencional y con cierta facilidad hasta 0,02 – 0,03 %, este valor es elevado [1] para laminar en caliente. Bajar el nivel de plomo hasta los valores exigibles por normas, requiere procedimientos especiales y costosos. La técnica cuyo mecanismo aquí se investiga, consiste en ajustar el contenido de plomo y estaño dentro de ciertas proporciones, ya que el balance de estos elementos, permite proceder sin problemas de fisuraciones a la colada y laminación en línea del cobre. Con el control de la composición química del sistema se logra que el plomo y el estaño se adhieran [2] sobre las partículas de eutéctico Cu-Cu2O. Esta disposición micro estructural en borde de grano explica la acción favorable del estaño en la maleabilidad. El procedimiento que aquí se describe no es aplicable a cualquier caso pues no funciona en materiales con contenido elevado de oxígeno (“Tough pitch”) ni en cobres desoxidados. Solamente lo hace en formas de baja sección que hayan sufrido enfriamiento rápido.

Aug 7, 2018

By Sidiney Nascimento Silva

O trabalho descreve os principais resultados dos testes industriais realizados na Usina Presidente Vargas, CSN, Brasil, envolvendo a adição de um catalisador à mistura de carvões, em termos da qualidade do coque e do processo da coqueria. O catalisador em questão é o produto Thermact, que possui partículas nanométricas em sua composição, fornecido pela empresa Abhitech Energycon Limited, Índia. O catalisador foi dosado e adicionado à mistura de carvões via correia transportadora, na proporção, em peso, de 1kg de catalisador para 4.000kg da mistura de carvões. Os resultados dos testes realizados nas Baterias # 1, 4A, 4B e 5 com a adição de um catalisador à mistura de carvões, sinalizaram a viabilidade técnica e financeira da sua aplicação no processo da coqueria. Os principais benefícios decorrentes da adição do catalisador foram: i) aumento potencial da capacidade de produção de coque ao redor de 10% ou, alternativamente, melhoria da qualidade do coque - aumento de 1,4% do valor médio do índice de resistência mecânica a frio do coque, DI150/15, mantendo-se o tempo total padronizado do processo de coqueificação, visando à preservação das Baterias, ou ainda, a utilização de uma mistura de carvões de menor custo, sem prejuízos ao atendimento à especificação do coque para os Altos-Fornos; b) aumento da geração e redução do consumo de gás de coqueria, GCO; iii) aumento na produção de BTX (Benzeno, Tolueno, Xileno) e redução da produção de alcatrão na Planta de Carboquímicos; iv) limpeza do sistema “PROven”, “goosenecks”, tubos de ascensão e paredes dos fornos, sinalizando a sua viabilidade técnica e econômica.

Aug 1, 2018