Iranian Journal of Oil and Gas Science and Technology

Abstract In steel production plants, such as those manufacturing sheets, pipes, and round bars, raw materials are annealed in preheating furnaces at approximately 1200 °C before undergoing hot deformation. Substantial oxidation and loss of raw steel materials occur in preheating furnaces, resulting in significant economic losses. A potential solution to reduce losses in this scenario is the application of protective ceramic coatings. This research investigates the effect of a ceramic coating based on Al₂O₃–SiO₂ on the oxidation behavior of steel sheets. The industrial-scale impact of the coating on the oxidation of steel slabs is also examined. The coating was applied using a spray method with slurry ceramic materials dispersed through a compressed air flow. Thickness measurement tests, scanning electron microscopy, and energy dispersive X-ray spectroscopy (EDS) analysis were conducted to evaluate the kinetics, microstructure, and oxidation behavior of the coatings. The findings indicated that the oxidation kinetics for uncoated steel sheets followed a parabolic trend, while the kinetics for ceramic-coated samples exhibited a slower logarithmic behavior. The application of the coating resulted in a reduction of the oxide layer thickness by less than 30% compared to the uncoated samples, attributed to a lower diffusion coefficient in the coated samples. Applying the ceramic coating on ST52 slabs in industrial tests led to a significant reduction in the oxide layer thickness and a more straightforward peel of the oxide layers. This showed that using such ceramic coating for materials in preheating furnaces could effectively reduce oxidation losses and enhance the mechanical quality of final products.