Stress-controlled hydrogen embrittlement failure in U-bend high-strength steel

柴山 由樹; 北條 智彦*; 小山 元道*; 秋山 英二*

International Journal of Hydrogen Energy, 88, p.1010 - 1016, 2024/10

https://doi.org/10.1016/j.ijhydene.2024.09.123

The effect of plastic deformation on the hydrogen embrittlement behavior of high-strength martensitic steels was investigated using a U-bend test. The hydrogen embrittlement susceptibility appeared to be enhanced with increasing plastic strain. Based on fractographic and stress-strain analyses, the maximum principal stress dominated the hydrogen embrittlement fracture. Although the apparent enhancement with increasing plastic deformation was observed, the origin of the enhancement was increased residual stress arising from the evolution of graded plastic strain during U-bending. We conclude that residual stress rather than plastic strain induced by plastic deformation strongly affects hydrogen embrittlement susceptibility in deformed high-strength steel components.

DBTT measurement by use of small punch(SP) test

鈴木 雅秀; 深谷 清; 西山 裕孝; 衛藤 基邦

JAERI-M 92-086, 44 Pages, 1992/06

JAERI-M-92-086.pdf:2.79MB

微小試験片による延性脆性遷移温度(DBTT)の評価法について、スモールパンチ(SP)試験を中心に検討を行った。熱時効、冷間加工、中性子照射を行った21/4Cr-1Mo鋼及び鉄基モデル合金を用い、SP試験によるDBTT評価の課題を検討した結果、SPによるDBTTとシャルピー試験によるDBTTは全般的には良い相関が得られた。しかしながら、粒界脆化型のDBTTの上昇に関しては、SP試験片の破壊破面観察等を組み合わせることにより、脆化のより的確な判断を行っていく必要があることが判った。