Recent developments in sour service line pipe steels

This paper reviews the evolution of Hydrogen Induced Cracking (HIC) test requirements over the last 30 years for line pipe intended for sour service. As a result of the steadily increasing demands it has become progressively more difficult to fulfil the requirements of the standard testing conditions. As a result of the imposed very severe NACE TM0284 (Solution A) HIC test conditions the overall profile of requirements (strength, toughness) can, in some cases, not be achieved consistently. Some typical examples for of sour service pipe production at EUROPIPE (formerly Mannesmann) over the past 20 years, and the details of recent production of sour service pipes, in grade X70 in wall thicknesses up to 35 mm, are presented. As a result periodic test failures a Fitness-for-Purpose approach has been applied. By way of example the results of a pipe order, for a special project where the fitness-for-purpose approach has been used to qualify the pipe, will be described. (AU)