Correlations for weight loss rate of pressureless sintered SiC with steam flow velocity, and temperature in pure steam at atmospheric pressure in laminar flow with a velocity range of 0.8–10m/s and a temperature range of 1140–1500°C have been developed. While preserving physical significance of non-dimensional numbers dictating boundary layer mass transfer phenomena, the correlations capture boundary layer diffusion effects on the SiO2 volatilization rate, which is affected by flow characteristics at the oxidizing surface. A correlation representing the additive resistances of the mass diffusion in the boundary layer and the volatilization reaction is found to best fit the experimental data. The developed correlations should help understand the SiO2 volatilization mechanism in steam, as well as predicting the lifetime of pressureless sintered SiC in oxidizing environments.