Influência de elementos químicos residuais do aço na qualidade do fio máquina enfornado a alta temperatura e laminado a quente

Abstract

In integrated and semi-integrated steel mills, the billet produced in continuous casting can be directed directly to the billet reheating furnace of the rolling mill, reaching temperatures around 850°C, which would guarantee significant fuel savings compared to stored billets. in patios that would be baked at room temperature. However, occasionally, low carbon steel billets, baked directly from the continuous casting and directed to the production of wire rod by hot rolling, show superficial defects, making it impossible to guarantee the quality of the product. Such defects, influenced by the mechanical conformation, may be related to the concentrations and types of residual chemical elements contained in the materials used in the production of billets in the electric arc furnace melt shop that uses metallic scrap as raw material. In this work, the influence of residual elements on the surface quality of the rolled wire rod was evaluated, using hot rolled billets. Tests were carried out on bench and in process, in order to evaluate four variables: time of the material in oven, temperature of the material in oven, chemical composition of the steel and subsequent mechanical forming process. The results showed that high levels of residual elements can generate surface defects and that mechanical shaping has a significant impact on the formation of these defects.