Thread Content
The surface quality of hot-rolled steel sheets and their corrosion resistance have always been important factors in assessing the quality of these sheets. The thickness and density of the oxide scale on the surface of hot-rolled steel sheets are directly related to their corrosion resistance, making them an important criterion for evaluating the surface quality of such sheets. How to achieve excellent quality of the surface scale, as well as its corrosion resistance during storage and logistics, has become an issue of widespread concern among steel rolling experts, corrosion scientists, and logistics managers. A dense scale commonly exists on the surface of hot-rolled steel, serving to protect its surface. However, this oxide layer is not perfect; it usually contains microscopic defects such as pores, microcracks, and voids. During storage or transportation in the atmospheric environment, oxygen and water molecules in the air can penetrate through these microscopic defects into the surface of the matrix, resulting in localized corrosion of the steel matrix and affecting the appearance and performance of the steel. The thickness, density, and compositional makeup of the scale affect the transmission and diffusion of corrosive agents such as oxygen and water within the scale, thereby directly influencing the corrosion resistance of hot-rolled steel sheets during storage and transportation. Therefore, studying the relationship between the type, structure, and composition of hot-rolled scale and its atmospheric corrosion resistance not only improves the performance of hot-rolled steel but also provides a basis for establishing time limits for storing and transporting hot-rolled steel sheets. Preliminary studies have been conducted on the relationship between rolling processes, the microstructural characteristics of the scale, and corrosion resistance. Research by Zhou Xianliang and others has shown that the scale formed through slow cooling is continuous, dense, and uniform, resulting in better corrosion resistance ； Studies by Dong Chaofang and others have found that after hot-rolled strip steel is curled, differences in oxygen supply at various positions along the width of the strip lead to significant variations in the structure and organization of the oxide scale, which in turn affects the corrosion resistance of this oxide scale ； Studies by Chandra et al. have shown that reducing the carbon content and increasing the curling temperature from 540 °C to 650 °C can enhance the adhesion between the hot-rolled scale and the substrate, thereby improving the corrosion resistance of the hot-rolled scale ； Studies by Perez et al. have shown that the alloying elements Cr and Mo in steel can also improve the corrosion resistance of the hot-rolled scale.