Influence of cooling path after rolling on sulfide stress cracking behavior for casing steel

Numerical Evaluation on Analysis Methods of Trapping Site Density in Steels Based on Hydrogen Permeation Curve

“…Besides fitting the experimental permeation curves, by means of the theoretical solution based on Fick’s diffusion law to obtain hydrogen effective diffusivity, the McNabb–Foster model [ 27 ] and Oriani’s local equilibrium theory [ 28 ] have also been proposed to integrate the trapping site’s effect on hydrogen diffusion behaviors in matrix, and establish the simplified relationship between trapping site characteristics and hydrogen effective diffusivity. With these theoretical foundations, two simplified formulas (Equations (1) and (2)) have been produced and widely utilized in the analysis of hydrogen permeation curves [ 22 , 26 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. where D eff is the hydrogen effective diffusivity examined in the experimental tests, D L is hydrogen diffusivity in matrix with trapping site effect; N t is trapping site density; N L is the density of interstitial site available for hydrogen in matrix; E B is the binding energy of hydrogen to trapping site and C 0 is the hydrogen concentration at the charging side at hydrogen permeation test.…”