Journal of the Korean Society of Mechanical Technology (한국기계기술학회지)

Korean Society of Mechanical Technology (한국기계기술학회)
권호 표지

The Finite Element Analysis on the Characteristics of the Hydrogen Diffusion for the Cr-Mo Steels

Cr-Mo강의 수소확산 특성에 관한 유한요소해석

  • 이휘원 (경기과학기술대학 정밀기계과) ;
  • 하민수 (경기과학기술대학 정밀기계과)
  • Received : 2011.05.12
  • Accepted : 2011.06.21
  • Published : 2011.06.30
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Abstract

The size of hydrogen molecule is not so small as to invade into the lattice of material, and therefore, hydrogen invades into the material as atom. Hydrogen movement is done by diffusion or dislocation movement in the near crack tip or plastic deformation. Hydrogen appeared to have many effects on the mechanical properties of the Cr-Mo steel alloys. The materials for this study are 1.25Cr-0.5Mo and 2.25Cr-1Mo steels used at high temperature and pressure. The hydrogen amount obtained by theoretical calculation was almost same with the result solved by finite element analysis. The distribution of hydrogen concentration and average concentration was calculated for a flat specimen. Also, finite element analysis was employed to simulate the redistribution of hydrogen due to stress gradient. The calculation of hydrogen concentration diffused into the material by finite element method will provide the basis for the prediction of delayed fracture of notched specimen. The distribution of hydrogen concentration invaded into the smooth and notched specimen was obtained by finite element analysis. The hydrogen amount is much in smooth specimen and tends to concentrate in the vicinity of surface. Hydrogen embrittlement susceptibility of notched specimen after hydrogen charging is more remarkable than that of smooth specimen.

Keywords

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