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In the present work, the water flux densities of nozzles with flat jet and full cone jet were experimentally measured using an apparatus in industrial scale that reproduces the secondary cooling of the continuous casting of round billets of Vallourec Tubos do Brasil. A mathematical model for heat transfer and solidification for the continuous casting of round billets was developed applying the experimental water flux density profile, establishing a non-uniform water distribution approach. The mathematical model was validated by experimental measurements of the billet superficial temperature, performed at the industrial plant. The results of the mathematical model using both uniform and non-uniform water flux density approaches were compared. The non-uniform water distribution approach enabled to identify important variations of the heat transfer coefficients and the billet temperatures, especially in the first cooling zone, and to assess more accurately the local effects of the water distribution on the thermal behavior of the strand. The non-uniform water flux density approach applied to the mathematical model was a useful and more accurate tool to improve the comprehension of the thermal behavior of the steel along the secondary cooling. [ABSTRACT FROM AUTHOR]

Samarco produces iron ore pellets thermally processed in Travelling Grate furnaces. This process is essential in order to obtain adequate mechanical strength to the pellets transportation and operation in the reduction reactors. All the mechanical properties of the agglomerates are obtained during the stage of firing, being a decisive step to pellet quality. Therefore, the velocity distribution of gas fl ow within this zone must be homogeneous. For this reason, it was developed a mathematical CFD model to characterize the gas fl ow in the burning zone, applying the equations of conservation of momentum, mass and energy. The validation of the model was obtained by measuring the temperatures inside the furnace. It was developed a wireless communication system in order to monitor continuously the evolution of the temperatures in the furnace. [ABSTRACT FROM AUTHOR]

This work investigates the variation of the apparent decarburization constant (kc) as function of the argon flow rate injected in a RH degasser. It allows optimization of the flow rate at each decarburization stage. For this, 97 ultra low carbon steel heats were analyzed using three different argon flow rates (80 Nm3/h, 110 Nm3/h e 140 Nm3/h). Steel samples were taken at 0, 6 and 12 minutes of each heat. In the first decarburization stage, the kc values were similar for the three tested flow rates. In this case, this flow rate was reduced from 110 Nm3/h to 80 Nm3/h and the argon consumption decreased in 18.900 Nm3/year. With this change, the temperature drop during the treatment and the gas volume to be sucked by the vacuum system were reduced. In the second decarburization stage, the flow rate of 140 Nm3/h remained due to the highest kc value. [ABSTRACT FROM AUTHOR]

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Copyright of Tecnologia em Metalurgia, Materiais e Mineração is the property of Associacao Brasileira de Metalurgia e Materiais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnologia em Metalurgia e Materiais is the property of Associacao Brasileira de Metalurgia e Materiais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)