| A study about understanding and modeling of Stress Corrosion Cracking (SCC) in high pressure pipeline steel was carried out by investigating the SCC propagation mechanism and kinetics first, and then simulating individual SC crack growth in a near neutral pH environment using the concept of TIP.; A thermodynamic approach accounted for the coupling between plastic deformation and electro-chemical corrosion in the SCC. SCC colony evolution related to the lifetime of the pipelines included colony initiation, individual SC crack growth, and multi-crack interaction based on the field examinations.; An accelerated test for simulating individual SC crack growth in a near neutral pH environment was performed. The concepts of Crack Layer theory were used to interpret individual SC crack growth. The process zone of crack layer in this case is composed of three sub-zones, a plastic deformation zone, a hydrogen diffusion zone, and an electro-chemical zone. The crack growth rate a˙ is expressed by a linear relation between a˙ and the associated thermodynamic forces. Experimental examinations of the proposed model led to the determination of the kinetic coefficients employed in the crack growth equation. Finally, the application of the individual crack growth law to random configurations of multiple cracks resulted in a simulation of SCC colony evolution. |
