Modelamento físico e matemático da formação de placa de Mistura no lingotamento Contínuo Efeitos de modificadores de fluxo no molde

• Ano de defesa: 2010
• Autor(a) principal: Renata Cristina Alves Elias
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: transição de qualidade; placa de mistura; fluxo; modificador de; Lingotameno contínuo; Engenharia metalúrgica; Metalurgia extrativa
• Link de acesso: http://hdl.handle.net/1843/BUDB-8DJHA3

An intermixed slab is formed when different grades of steel are cast in sequence and represents a loss for the steelmaking companies. Use of flow modifiers and reduction of the steel level in the tundish during grade transition to decrease the intermixing length have a limited effect. Beyond a certain point, the length of the intermixed slab is mainly determined by the mixing that occurs inside the mold. To further reduce the intermixinglength, it is necessary to change the flow pattern inside the mold.Previous studies, using physical and mathematical models, have identified the main factors that affect the length of the intermixed slab. These studies present two significant limitations, - only the mixing that occurs in the tundish is considered; - the procedure adopted in the industry, during grade transition, was not considered. In the present paper, the use of flow modifiers in the mold was proposed andinvestigated using mathematical modeling of the fluid flow inside the mold. The model was developed using a commercial software, ANSYS-CFX11. Different configurations of flow modifiers were investigated. To validate the model predictions, grade transitionexperiments were conducted using fully integrated and automated physical models of a tundish and a mold (strand) of a two-strand continuous slab caster. It was determined that the flow modifiers tested in the present work could lead to significant reductions in the length of the intermixed slab. Flow modifier type B (consisting of two boards with special shape) lead to reductions of up to 40% in the intermixing length.