Water Vapor Contribution to the Erosion of Steel by High Temperature Flows

Experimental results on the role of water vapor in the mass loss mechanism of steel by hot, high pressure flows are described and interpreted in terms of a surface reaction model. Situations in which highly transient heat transfer and chemical interactions at the gas-metal interface produce erosion of the surface occur in a variety of systems, e.g., gun barrels, gas turbines, vents, nozzles, and furnaces. This research is directed at conditions in which the metal surface temperature remains below the melting point and mass loss is the result of chemical attack. The rate of reaction depends on the unsteady pressure and surface temperature. The study reveals that in high shearing flows, when the build-up of oxide protective layer is limited, surface chemical attack of the steel by water vapor can be the main erosion source in combustion gas atmospheres, and the process is controlled mainly by turbulent transport phenomena.