Oxidation behavior of carbon steel in simulated kerosene combustion atmosphere: A valuable tool for fire investigations

Abstract

SummaryFire investigations aim to establish the origin and cause of fires by collecting and analyzing the comprehensive fire‐related evidences. Metallic materials exposed to the fire scene environments are usually subjected to melting and/or high‐temperature oxidation, and they have been considered vital parameters for temperature determination, as recommended in NFPA 921. The oxide characteristics obtained from the conventional fire investigations primarily rely on simple visual observations such as the variations in oxide color, the so‐called “oxidation patterns.” However, such information is not sufficiently convincing due to the complex nature of oxides formed in the fire scene. The oxide color is strongly affected by the type of oxide, the oxide thickness, the concentration of contaminant, and the interactions among different oxides. In this study, Q235 structural steel samples have been exposed to high‐temperature air and simulated kerosene combustion conditions at certain temperatures and for indicated periods. The oxidation rate was examined by thermogravimetric analysis. The morphologies and microstructures of the oxide scales were investigated by scanning electron microscopy, energy dispersive spectroscopy, and X‐ray diffractions. The results show that the oxide properties are strongly dependent on the oxidation temperature and oxidation atmospheres. These oxidation behaviors are expected to provide useful information on identifying fire characteristics.