Melt flow control in a multistrand tundish using a turbulence inhibitor
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I. INTRODUCTION
MELT flow control in tundishes with one or two strands using dams, weirs, and baffles has been widely studied using water models.[1–8] Melt flow in multiple-strand tundishes for billet and bloom casters has been studied using water modeling and mathematical simulation techniques.[9–14] More recently, these techniques also have been employed to develop turbulence inhibitors. These devices are essential to decrease fluid turbulence in the pouring region in oneand two-strand tundishes.[15–20] Turbulence inhibitors have been shown to be very useful to avoid slag entrapment, pick up of oxygen and nitrogen from the surrounding air during ladle changes, and decrease downgraded steel during grade changes. It is a usual trend that, similar to other melt flow control devices (MFCD), a turbulence inhibitor (TI) should be designed and manufactured on a tailor-made basis. Every TI should be designed according to the tundish size, melt depth, flow rate, and tundish design. In the present work, melt flow control using a turbulence inhibitor in a four-strand tundish of a bloom caster is thoroughly studied. In this sense, this is the first report dealing with the employment of a TI in a multiple-strand tundish. A multiple-strand tundish presents various challenges such as being able to maintain the same casting temperature, homogeneous chemistry, and similar steel cleanliness in every strand. The objective in this work was to study the effects of a R.D. MORALES, Professor, and J. PALAFOX-RAMOS, Postdoctoral Student, are with the Department of Metallurgy and Materials Engineering, Institute Polytechnic National, ESIQIE, C.P. 07300, Mexico. J. de J. BARRETO, Professor, is with the Materials Graduate Center, Institute Tecnologico de Morelia, C.P. 58120-Morelia, Mexico. S. LOPEZ-RAMIREZ, formerly Postdoctoral Student, Department of Metallurgy and Materials Engineering, Institute Polytechnic National, ESIQIE, is Researcher, FOSECO INC., 20200 Sheldon Road, Cleveland, OH 44142. D. ZACHARIAS, Research Engineer, is with FOSECO INC. Manuscript submitted October 18, 1999. METALLURGICAL AND MATERIALS TRANSACTIONS B
TI on the fluid flow pattern, tracer diffusion, and tracer distribution in the different strands of a four-strand tundish of a bloom caster. Other important aspects considered were the melt flow performance comparisons, among the bare tundish, MFCD consisting of dams and a waved impact pad, and the TI itself. In order to obtain these objectives, water and mathematical modeling techniques were applied simultaneously, reaching useful conclusions in a complementary fashion. II. WATER MODELING A 1/3-scale model, using the Froude criterion, was constructed using transparent Perspex (Bodega de Pla´sticos, Mexico) plastic sheets with a thickness of 0.0127 m. Figure 1 shows the geometric dimensions of this model. As can be seen, the positions of the outlets are nonsymmetrical with respect to the central axis of both sides of the tundish. Three types of tundishes were studied: the bare tundish (BT), a tundish with MFCD consi
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