Directional drilling is a well-known and established technology having a long tradition within the oil and gas industry. Because of their versatility, austenitic CrMn-stainless steels are the most commonly used materials in non-magnetic drill collars including sophisticated directional, measurement-while, and logging-while drilling tools. In addition to their ideal non-magnetic character, these materials exhibit an excellent combination of strength, ductility and toughness properties necessary for the application. With the continued increase in operations with demanding service conditions, mainly characterized by high temperatures, and extreme corrosive environments containing large chloride concentrations, CrMnstainless steels have been pushed to their limits in terms of corrosion resistance. While intergranular corrosion requirements for CrMn-stainless steels used in drilling equipment are defined in API specification 7-1, resistance to typical application-driven failure mechanisms such as pitting and environmentally-assisted cracking are not properly defined in this specification. In addition, some of the standardized methods currently employed have recently shown limitations for reliably identifying sensitized microstructures. To address these gaps and redefine corrosion requirements for CrMnstainless steels, API task group 7047 has worked together with NACE TEG 514X to review current requirements and testing methods to identify deficits and opportunities for improvement. As a result, a round robin experiment involving steel mills and end-users was executed to evaluate the suitability of
alternative corrosion testing methods. This paper presents a review of this exercise and includes a comprehensive compilation of the results produced within the round robin experiment as well as the
conclusions drawn from those to modify current corrosion resistance requirements for CrMn-stainless
steels in API specification 7-1.