Fatigue Behavior of Super Duplex Stainless Steel Exposed in Natural Seawater Under Cathodic Protection

Frontiers in Materials

Materials

Geoffrey Ringot¹  Nicolas Larché¹  Flavien Vucko¹  Dominique Thierry² 

[1] French Corrosion Institute—RISE, Brest, France;French Corrosion Institute—RISE, Brest, France;RISE Research Institute of Sweden, Kista, Sweden;

关键词: super duplex stainless steel;    hydrogen;    natural seawater;    fatigue;    cathodic protection (CP);   

DOI  :  10.3389/fmats.2022.826189

 received in 2021-11-30, accepted in 2022-01-11,  发布年份 2022

来源: Frontiers

【 摘 要 】

Under operating conditions, alternated loading and fatigue are encountered, controlling the durability and safety of components and structures made of super duplex stainless steel (SDSS). In particular, the use of a cathodic protection (CP) system to protect the structure against corrosion can induce hydrogen charging of the SDSS. Thus, the aim of this study was to investigate the sensitivity of some industrial products made of SDSS 2507 (UNS S32750), without artificial thermal aging, under test conditions as close as possible to real environments. In situ fatigue tests under alternated 4-point bending conditions were conducted in natural seawater with and without CP. The fatigue behavior was evaluated as a function of environmental parameters, such as temperature, and material parameters, particularly the austenite spacing and microstructure around orbital welds by Tungsten Inert Gas (TIG) welding and stress concentrations, through the presence of surface defects. The fatigue life obtained in air or in seawater at the open circuit potential (OCP) was rather similar. Fatigue life enhancement was systematically observed under CP particularly in the range of low applied load, despite evidence of brittle failure on the fracture surfaces of samples tested under CP. The data suggest immunity of the SDSS to hydrogen embrittlement under the present experimental conditions of fatigue testing.

【 授权许可】

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Copyright © 2022 Vucko, Ringot, Thierry and Larché.