Análise da remoção de inclusões do aço durante o esgotamento da panela após injeção de gas inerte através de modelamento físico

• Ano de defesa: 2018
• Autor(a) principal: Pedro Henrique da Rocha Silva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia metalúrgica; materiais e minas; Metalurgia extrativa; Aço Inclusões; Siderurgia
• Link de acesso: http://hdl.handle.net/1843/RAOA-BBQNEC

The steelmaking industry has a significant importance in many countries economic basis. The development of high quality and less costly steels has become essential to the survival of this industry. Therefore, steels with extremely low amounts of inclusions, the so-called clean steels, are aimed. The present work had the objective of investigating the production of low inclusion grade steels through gas injection using a porous plug located at the bottom of the steelmaking ladle. This investigation was developed by means of physical modeling. A physical model of a steelmaking ladle, in scale of 1:5 was built. Experiments evaluating the effects of different variables, such as gas flow rate, gas injection time, position of the porous plugs and superficial area of the porous plugs were carried out. The size distributions of the inclusions remaining in the liquid steel and the bubble diameters were also determined. Two main effects were proposed, inclusion removal and reversion. Both effects are present in all variables, in distinct moments, revealing the existence of an optimum point for each of them. Regarding plug surface area, the larger the plug, the better the treatment. Regarding the gas flow rate, the intermediary brings better results. The treatment time should be larger to small flow rates and smaller to the larger flow rates for good results. The position of the porous plug does not seem to affect the treatments. Larger inclusions are easily removed to the upper layer of the liquid and for most of the plugs, flow rates and treatment times. Smaller inclusions are harder to remove and the better results are obtained with low gas flow rates and longer times. The bubble size has a great influence on the treatment. Larger bubbles lead to better results for lower treatment times and smaller bubbles enable better results for longer treatment times. The optimum values for inclusion removal treatment were 0.19 to 0.58Nl/min/ton for the gas flow rate and 180s for the gas injection time