This standard addresses the testing of metals for resistance to cracking failure under the combined action of tensile stress and corrosion in aqueous environments containing hydrogen sulfide (H2S). This phenomenon is generally termed sulfide stress cracking (SSC), when operating at room temperature and stress corrosion cracking (SCc)'1> when operating at higher temperatures. In recognition of the variation with temperature and with different materials this phenomenon is here called environmental cracking (EC)_(lJ For the purposes of this standard, EC includes only SSC, SCC, and hydrogen stress cracking. The primary purpose of this standard is to facilitate conformity in testing so that data from different sources can be compared on a common basis. Consequently, this standard aids the evaluation and selection of all types of metals and alloys, regardless of their form or application, for service in H2S environments. This standard contains methods for testing metals using tensile, bent-beam, C-ring, and double-cantilever-beam (DCB) test specimens. Certain ASTM( 2) standard test methods have been referenced for supplementary tests, creating a comprehensive test method standard.
1.1 This standard covers the testing of metals subjected to tensile stresses for resistance to cracking failure in low-pH aqueous environments containing H2S. Carbon and low-alloy steels are commonly tested for EC resistance at room temperature where SSC susceptibility is typically high. For other types of alloys the correlation of EC susceptibility with temperature is more complicated.
1.2 This standard describes the reagents, test specimens, and equipment to use, discusses base material and test specimen properties, and specifies the test procedures to follow. This standard describes four test methods:
Method A- Standard Tensile Test
Method B - Standard Bent-Beam Test
Method C- Standard C-Ring Test
Method D - Standard Double-Cantilever-Beam (DCB) Test
Historical Document 1996