Investigation of the Thermochemical Erosion Properties of High-Strength Steel Surfaces in High-Temperature Propellant Gas

In this study, an experimental apparatus was designed to measure the thermochemical erosion properties of gun steel samples. Three tests were conducted in propellant gas to analyze the surface, cross-sectional morphology, and major element distribution. The results show that the specimen surface undergoes significant erosion by the hot gas, forming a porous white layer with a low melting point. The white layer's thickness and degree of damage increase with prolonged erosion time. During erosion, abundant amounts of carbon and oxygen migrate to the surface and bonded with iron. Carbonation reduces impact toughness, while oxidation increases metal volume, resulting in a more porous white layer. Consequently, many microcracks form within the white layer, which grow and intersect with deepening erosion. These findings suggest that surface erosion can lead to fracturing and breakage of the material, ultimately increasing exposure of the substrate to gas and accelerating the erosion rate.