A Microtexture-Microstructure Model to Simulate Intergranular Stress Corrosion Crack Propagation in Pipeline Steel

Electron backscattered diffraction (EBSD) investigations were carried out to obtain the microtexture, grain boundary character, and physical microstructural parameters, such as the grain size and grain shape distributions, of API X65 pipeline steel that experienced extensive intergranular stress corrosion cracking (IGSCC). The orientation distribution functions (ODF) and the grain boundary character distributions (GBCD) of the cracked and crack-arrest microstructures were obtained from the EBSD data of the corresponding regions. First, a Voronoi algorithm based microstructure reconstruction model has been utilized to generate model microstructure that resembles the experimentally observed ones. Subsequently, a Markov Chain–Monte Carlo model, coupled with the grain boundary character and orientation dependent vulnerability statistics, has been employed to simulate the crack propagation behavior. The simulation results are in good agreement with the experimental observations.