SCM435鋼陰極水素チャージ試験片のSSRTによる耐水素性評価

抄録

As an alternative method to evaluation of slow strain rate technique (SSRT) under high-pressure hydrogen gas, SSRT tests were performed with a cathodically charged specimen. Cathodic charging was performed in 3% NaCl aqueous solution with pH=6 and at a current density of 50 to 600 A⁄m². Cr-Mo low alloy steel with a tensile strength of 1000 MPa grade was selected as a test material. Relative reduction of area (RRA) values obtained by tests with continuous charge at a cathode current density of400 A⁄m² were equivalent to those performed in hydrogen gas at pressure of 100 MPa. Fracture surface observations were also performed using scanning electron microscopy (SEM) . The quasi-cleavage fracture surface of hydrogen embrittlement (QC_HE) was observed near the surface of specimen that were subjected to continuously hydrogen charged tests. It was necessary to charging hydrogen during a certain level of plastic deformation to form the QC_HE. The results show that to simulate the high-pressure hydrogen gas test, it was necessary to perform the hydrogen-charged until rupture.