J. Mater. Sci. Technol. ›› 2015, Vol. 31 ›› Issue (11): 1144-1150.DOI: 10.1016/j.jmst.2015.09.002

• Orginal Article • Previous Articles     Next Articles

Crack Initiation Mechanism of Z3CN20.09M Duplex Stainless Steel during Corrosion Fatigue in Water and Air at 290?°C

H.C. Wu1, B. Yang1, 2, Y.Z. Shi1, Q. Gao1, Y.Q. Wang3   

  1. 1 State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China; 2 Collaborative Innovation Center of Universal Iron & Steel Technology, Beijing 100083, China; 3 School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002, China
  • Received:2015-01-05
  • Contact: * Corresponding author. Ph.D.; Tel.: +86 1062333351; Fax: +86 10 62333351.E-mail address: byang@ustb.edu.cn (B. Yang).
  • Supported by:
    The authors would like to appreciate the financial support from the “863” Program of China under Nos. 2008AA031702 and 2012AA03A507.

Abstract: The crack initiation mechanism of a Z3CN20.09M duplex stainless steel (DSS) during corrosion fatigue (CF) in water and air at 290?°C was investigated by using a CF cracking machine and a scanning electron microscopy (SEM). The cracks were initiated successively at the persistent slip bands (PSBs), phase boundaries (PBs) and pitting corrosion points (PCPs) of the specimens when they were tested in water at 290?°C, while in air at 290?°C the cracks were only initiated at the PSBs and PBs. And the cracks were found mainly to initiate at the PSBs and PBs when the specimens were tested in water and air at 290?°C, respectively. The results also reveal that the cracks were likely to be initiated at the first 20% of fatigue life of the specimens tested in water at 290?°C. However, the cracks were not found until 50% of fatigue life when tested in air at 290?°C. Moreover, the crack numbers of the specimens tested in water at 290?°C were much more than those tested in air at 290?°C.

Key words: Duplex stainless steel, Corrosion fatigue, Crack initiation, High temperature water