Hydrogen Trapping Behavior in a Strained Ferritic-Martensitic Dual Phase Steel




Abstract: Hydrogen Embrittlement (HE) susceptibility is effected by hydrogen trapping at various defects introduced by press forming in ultra-high strength. Further, it is well known that the volume of hydrogen trapping sites can be changed by deformation. Therefore, it is important to comprehend the influence of deformation on hydrogen trapping sites. Purpose of this study is to identify the hydrogen trapping sites in ultra-high strength steel sheet.1180 MPa grade dual-phase steel was used. Various levels of strain were applied to the samples by rolling, which was followed by cathodic electrolytic hydrogen charging. Hydrogen desorption rate was measured from 223 K using a Thermal Desorption Analysis device (TDA), which enables evaluation of each hydrogen trapping site. Some types of hydrogen trapping sites were identified. It is considered that these hydrogen trapping sites were correspond to dislocation, various interfaces of martensite and vacancies, respectively.

Authors: Hiroshi Okano and Shusaku Takagi

Keywords: Hydrogen Embrittlement, Trapping Sites, Dp Steel, Thermal Desorption Analysis,Gaussian Function, Peak Separation

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5 pages


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