Analysis of Oxide Film on X65-Line Pile Steel Formed in Hydrogen Induced Cracking Environment by Dynamic Nano-indentation Method

동적 나노압칩법을 이용한 수소유기균열분위기에서 생성된 X65-석유수소용 강관의 산화막 분석

The oxide film was formed in hydrogen induced cracking (HIC) environment by potentio-dynamic method. Corrosion potentials and rates of the X-65 and X-80 line pipe steels were -0.3495 $V_{SHE}$, $2.833{\times}10^{-3}A/cm^2$ and 0.2716 $V_{SHE}$ and $2.533{\times}10^{-3}A/cm^2$, respectively. Surface composition analysis of the oxide film contained sulfur. Thermodynamic analysis of the HIC solution chemistry suggested that the oxide phase consisted of iron sulfate. Dynamic nano-indentation method applied to determine nano-hardnesses of the oxide film and base metal hardness.