Influence of liquid accelerant on scaling behavior of stainless steel in fire: An experimental study

Among the commercial materials, stainless steel is widely used in our daily life and can be hardly destroyed by flame or the heat emanating from a fire. In this fundamental work, the formation and development of oxide scale on stainless steel 1Cr11Ni2W2MoV were investigated at 600 degrees C to 800 degrees C in the atmospheres with and without liquid accelerant. The aim of this work is to figure out the influence of accelerant on the oxidation pattern of stainless steel at high temperature that occurs in a fire. The morphology, microstructure, and the growth rate of the oxide scales were characterized by thermogravimetric analysis, visual analysis, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The results revealed that the oxide scale formed on the stainless steel 1Cr11Ni2W2MoV was mostly protective in both atmospheres from 600 degrees C to 800 degrees C, except that breakaway oxidation occurred locally that resulted in the formation of intrusion oxide. Both increasing temperature and the presence of kerosene in combustion atmosphere increased the mass gain of stainless steel, which was mainly attributed to the occurrence of local breakaway oxidation. Consequently, the addition of accelerant just increased the formation trend of local intrusion oxide, rather than remarkably affect the scaling behavior. Therefore, careful analysis is needed to identify the presence possibility of accelerant in oxidation atmosphere according to the scaling behavior of stainless steel. Characterization of surface scale and metallurgical analysis of metallic material are expected to be supplementary technique for fire characterization in the future.