Keywords

Rationale

Ambiguous wording in G47 can result in differences in interpretation and application of metallographic examination requirements. Clarification of when and why metallographic examination is required for different types of specimens (i.e. for C-rings specimens and for tension specimens is needed. Because of the differences in severity of testing for tension specimens vs. c-rings (see section 6.1) and the possible interferences described in Section 5, the metallographic examination requirements are different. Failures of C-ring specimens for susceptible SCC material may not be readily obvious with visual examination alone so metallographic examination is needed to determine whether or not SCC is present. For tension specimens the interferences described in Section 5 may result in an overload fracture and metallographic examination can be used to determine the failure occurred due to SCC or due to these interferences. Changes to Section 9 and 10 are proposed to clarify the when metallographic examination is required and to illustrate the appearance of lined up pitting in section 9.2.3.1 and the measurement of intergranular fissures per section 10.3.1.