Session: MF-20-02 Material Quality and Failure Analysis-2

Paper Number: 123551

123551 - Microstructural Effect on Hydrogen Embrittlement of Line Pipe Steel and Its Weldment Under High-Pressure Hydrogen Gas 

With the implement of carbon neutrality for solving environmental problems such as global warming and abnormal climate, the use of hydrogen energy is becoming necessary and it is expected that pipeline will be utilized for long-distance inland transportation of hydrogen. However, in the case of steel materials exposed to a high-pressure hydrogen gas, the mechanical degradation, which reduces strength and toughness due to hydrogen diffused into the steels, can occur. Moreover weldment is known as the inferior inhomogenious microstructures on mechanical properties and has more sensitivity to hydrogen, and confirmed that weld heat affected zone was the most suceptible to hydrogen embrittlement. In this study, the effect of microstructures on hydrogen embrittlement in line pipe steel and its weldment accompanying the pipe-manufacturing process (SAW, ERW) was investigated. Hydrogen-related mechanical degradation evaluation were performed using a cathodic electrochemical hydrogen charging method, which corresponded to 10MPa high-pressure hydrogen service environment, and the amount of accumulated hydrogen in specimens was detected through the thermal desorption gas chromatography analysis. The material properites such as RRA, RNTS and fracture toughness(K) under hydrogen environment were evaluated to determine the optimal microstructures for improving hydrogen resistance and discussed in terms of hydrogen diffusion and trapping behavor characteristics.

Presenting Author: Kang-MooK Ryu POSCO

Presenting Author Biography: Majored in HE

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