PSI - Issue 41

Ericha Dwi Wahyu Syah Putri et al. / Procedia Structural Integrity 41 (2022) 266–273

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Putri et al. / Structural Integrity Procedia 00 (2022) 000 – 000

Fig. 6. Illustration of tensile specimen

Tension specimens that include machined notches are appropriate for analyzing SCC and hydrogen embrittlement (Bacchi et al., 2020). The presence of a notch induces a triaxial stress state at the root of the notch, in which the actual stress will be greater by a concentration factor that is dependent on the notch geometry. The advantages of such specimens include the localization of cracking to the notch region and acceleration of failure. 3.4. Slow Strain Rate Testing Slow strain rate testing (SSRT) is a method for investigating the quantitative relationship between notch tensile strength and hydrogen content of materials (Zou et al., 2017). SSRT is more advantageous than other SCC testing methods because it has less cost, more straightforward test procedures, and a comparatively shorter test-completion period. However, this method is required more aggressive test conditions and elaborate facilities. SSRT testing method uses the ASTM G-129 standard (Duan et al., 2020). SSRT was conducted in a corrosive environment and in the air to produce the SCC susceptibility indices (Iscc) was calculated by the ratio of mechanical properties. If the Iscc value is lower, the higher the SCC susceptibility (Huang et al., 2018). SCC susceptibility is represented in terms of susceptibility index (Iscc) as in Equation 4: I SCC = (El Gly −El SCC ) El Gly × 100 (4) where El Gly and El Gly are the elongations measured at the corrosive environment. Iscc is the SCC susceptibility index. The SCC susceptibility indices (Iscc) were calculated by taking the ratio of a particular mechanical property obtained from SSRT tests in the corrosive environment to its corresponding value in air. It means that the lower the Iscc value, the higher is the SCC susceptibility.

Fig. 7. Schematic diagram of experimental for SSRT testing