Computer-based simulation of the service-life of metallic tubes used at high temperatures

Abstract

The aim in this paper is to introduce a computer simulation tool, which is designed for prediction of service-life of components operating under corrosive conditions such as oxidation and nitridation at high-temperature. Many laboratory experiments were carried out for the verification of the simulation results. Different classes of materials were exposed to different corrosive atmospheres at temperatures between 550oC and 1000oC. The tool for the prediction of internal/inwards corrosion processes at high-temperatures makes use of the numerical finite-difference technique to treat diffusional kinetics at one hand and the concept of local equilibrium thermodynamics on the other. For this purpose, a link has been established between the numerical environment of MATLAB and the thermodynamic library ChemApp. Using this new tool, the kinetics of nitridation and oxidation processes were predicted numerically taking the material’s microstructure into consideration by distinguishing between precipitation along the grain boundaries (sensitisation) and within the grain interior. Excellent agreement between experimental observations and simulation results revealed the high potential of the computer modeling application to complex corrosion processes.