Standard Techniques of Stress Corrosion Cracking Testing: A Review

This paper aims to provide a compendium of basic information that is easy to read and grasp and readily available for consultation by: students, engineers, and researchers who are not yet much experienced in stress corrosion cracking (SCC) testing but need such information for furthering their knowledge on the subject. SCC has been reaffirmed as an unpredictable dangerous form of corrosion that is often inevitable in engineering service of equipment, vessels, vehicles, buildings, etc.; even with their high technological designs. Proper SCC testing is noted to be crucial for providing threshold tensile stress information for reliable environmental SCC prevention of critical engineering structural components in service. Various standard techniques of SCC testing from the literatures have been reviewed, elucidated with few recent previous researches by some practitioners, and presented. The review has shown that basically, SCC testing involves procurement of test materials in wrought form, and production of specimens to consistent dimensions and uniform smooth surface finish. Other noted essential issues involved in SCC testing are removal of residual stresses in specimens before testing them, and chemical composition and morphological characterization of specimens before and after exposing them in the test environment for determined durations. The paper shows that about 90% of SCC tests are done under constant elastic tensile strain or load with smooth bent beam, U-bend, C-rings, and precracked tensile specimens against strain rate techniques. In order to obtain better applicable test results, it is advisable to always conduct tests with a given material type under different elastic stresses in each given environment using two or more different standard specimen preparation, characterization, and straining techniques to get optimal tensile stresses or strains by overall analysis of results.