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This document helps to establish the technical basis for accurately using the double cantilever beam (DCB) test.
API sponsored research on the methodology of continuous DCB testing. This work established the testing conditions of specimen design, arm displacement, chemical makeup of the aqueous test solution (composition and pH), time, and temperature. This has brought the state of the art to the point where the proper arm displacements can be selected for both NACE standard conditions and for fit-for-purpose conditions, thereby minimizing the number of invalid tests.

The rapidly expanding use of C-110 casing in the search for new supplies of oil and gas in sour formations has made it crucial to accurately characterize the resistance of such tubulars to sulfide stress cracking (SSC). This is best done by the DCB test, the only test that gives a numeric value from each specimen (other tests rely on the statistical analysis of fail/no-fail results, a process that does not give such rapid and precise ratings as does the DCB test). For this reason, the DCB test has gained wide acceptance since it was standardized by NACE in 1990.