L51623 Environment Sensitive Cracking (Low pH Stress-Corrosion Cracking) of High Pressure Pipelines

This is a review of the current situation relating to transgranular environment sensitive cracking of the type experienced on an in-service pipeline, by comparison with the commoner intergranular cracking experienced on many systems. It is probable that the cracking is not unique. Quite apart from the crack paths, there are other significant differences between the conditions in which the two types of cracking occur, particularly in relation to the environments involved, and sufficiently so to indicate that the mechanisms of cracking are different. The circumstances in which the two types of environment form are discussed. If the creation of a
reliable model for practical application to transgranular cracking is to be achieved, there is need for data relating to the effects of stressing conditions upon the crack nucleation and  growth rates of such cracks and of the circumstances in which these cracks coalesce.