Four-point bend testing is used extensively in the oil and gas industry to evaluate resistance of metals Four-point bend testing is used extensively in the oil and gas industry to evaluate resistance of metals to sulfide stress cracking and stress corrosion cracking. The face of the specimen to be tested is stressed in tension and the reverse face in compression. The test is carried out for a specified exposure period with the specimen held under constant displacement using compact loading jigs. The compact nature of the jigs enables testing of several specimens in the test vessel simultaneously. Despite the apparent simplicity of the test, there are many factors that can influence the test results. The purpose of this standard is to establish a reliable methodology for conducting the tests to enhance repeatability and reproducibility of test data. The results of the tests can then be used with greater confidence to rank the performance of metals, the relative aggressiveness of environments, and to provide a basis for qualifying metals for service application. As such, the standard will be of particular benefit to materials and corrosion engineers in the oil and gas sector and to test laboratories providing critical data.

Keywords: Stress corrosion cracking (SCC), sulfide stress cracking (SSC), four-point bend, strain measurement, strain gauging, hydrogen sulfide