| Title |
Effect of Nitrogen Addition on Martensitic Transformation and Hydrogen Embrittlement Behavior in Cold-Drawn Austenitic Stainless Steels |
| Authors |
천하은(Ha-Eun Cheon) ; 홍성규(Sung-Kyu Hong) ; 김성환(Sung-Hwan Kim) ; 홍성박(Seong-Pak Hong) ; 이욱진(Wook-jin Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2026.64.7.644 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Cold drawing; Hydrogen; Hydrogen embrittlement; Nitrogen; Stainless steel |
| Abstract |
Hydrogen embrittlement (HE) resistance of cold-drawn austenitic stainless steels was investigated by comparing STS316L and high-nitrogen stainless steel under identical cold drawing and high-pressure gaseous hydrogen charging conditions (10 MPa, 150°C, 600 h). Microstructural characterization, slow strain rate tensile (SSRT) tests, thermal desorption spectroscopy (TDS), and fractographic analysis were conducted to examine the effects of compositional differences on strain-induced martensite formation, hydrogen trapping behavior, and deformation characteristics. X-ray diffraction analysis revealed that both steels showed no detectable martensite after cold drawing. After SSRT, the a'-martensite fraction was 39 vol% in STS316L and 28 vol% in high-nitrogen stainless steel, indicating that the compositional differences of high-nitrogen stainless steel, including higher austenite stability, suppressed strain-induced martensitic transformation. The relative reduction of area (RRA) was 91% for STS316L and 100% for high-nitrogen stainless steel, demonstrating superior HE resistance of the high-nitrogen steel. TDS analysis showed that high-nitrogen stainless steel exhibited a higher total diffusible hydrogen content (6.65 wtppm) compared to STS316L (4.72 wtppm), yet maintained greater HE resistance. Peak deconvolution revealed that STS316L exhibited greater concentration of desorption in the high-temperature region, suggesting differences in the binding energy distribution of hydrogen trap sites between the two steels, consistent with the higher a'-martensite fraction observed after SSRT. These findings suggest that the superior HE resistance of high-nitrogen stainless steel is associated with suppression of martensitic transformation and reduction of high-energy trap site density through its overall compositional design, supporting its potential as a structural material for hydrogen infrastructure applications. |