Anisotropy of cold-worked Type-304 austenitic stainless steel: Focus on the hydrogen diffusivity. (26th July 2019)

• Record Type: Journal Article
• Authors: Sezgin, Jean-Gabriel; Takatori, Daichi; Yamabe, Junichiro
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 36(2019)
• Page Start: 20516
• Page End: 20528
• Publication Date: 2019-07-26
• Subjects: Austenitic stainless steel -- Hydrogen diffusion -- Finite element method (FEM) -- Cold-working -- Strain-induced martensite transformation; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.05.175
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Anisotropic nature of effective hydrogen diffusivity was investigated on a cold-worked (CW) Type-304 stainless steel. The material was characterized by using disk-shaped specimens sampled from two directions of steel plates with various rolling ratio. The thickness direction of the disks was parallel to the rolling direction for SL specimens and perpendicular for LT ones. Electromagnetic induction (EMI) and electron backscatter diffraction (EBSD) clarified the content and distribution of strain-induced martensite (SIM). The effective diffusivities and solubilities were jointly determined by desorption method and thermal desorption analysis (TDA) in H-charged specimens with high-pressure gas. The increase of SIM with CW ratio and the differences of SIM distribution observed between LT and SL specimens could justify the anisotropic effective diffusivities. Finite element method (FEM) was used to simulate permeation tests based on multiple EBSD maps. Simulations supported the experimental findings: at the CW ratio of 60%, the CW process increased the diffusivity by twenty and the diffusivity was five time greater in the SL specimen than the LT one. The inhomogeneous SIM distribution justified the modifications of diffusion properties by CW in both specimens. Highlights: Martensite was formed during Cold-Working (CW) of a Type-304 stainless steel. The fraction and distribution of martensite was dependent of CW ratio. Experiments showed an anisotropic H diffusivity increasing with the CW ratio. FEM simulations have reproduced the experimental tendencies in both directions. Anisotropic nature of the H diffusivity is a result of the martensite distribution.