Abstract
As an alternative method to evaluation of slow strain rate technique (SSRT) under high-pressure hydrogen gas, Continuous Cathodic Hydrogen Charging SSRT tests were performed. Cr-Mo low alloy steel with a tensile strength of 1000 MPa grade was selected as a test material. Cathodic charging was performed in 3% NaCl aqueous solution at a current density of 400 A/m2 and 1N-NaOH aqueous solution at 1.354 V constant potential test. Relative reduction of area (RRA) values obtained by tests with continuous charge at a cathode were equivalent to those performed in hydrogen gas at pressure of 69 ~ 115 MPa. The amount of hydrogen was measured using TDA. Amount of diffusible hydrogen is 0.74 ~1.09 ppm, which is equivalent to using hydrogen gas with a pressure of 69 ~ 115 MPa. Fracture surface observations were performed using scanning electron microscopy (SEM). The quasi-cleavage fracture surface of hydrogen embrittlement (QCHE) was observed near the surface of specimen that were subjected to continuously hydrogen charged tests.
