Heat Treatment of Metals ›› 2022, Vol. 47 ›› Issue (4): 108-115.DOI: 10.13251/j.issn.0254-6051.2022.04.017

• MATERIALS RESEARCH • Previous Articles     Next Articles

Precipitation behavior of σ phase in 2507 super duplex stainless steel

Bai Qingqing1,2, Zhang Zhihong1,2, Zheng Huaibei1,2, Wang Yinghu1,2   

  1. 1. Chengdu Advanced Metal Materials Industry Technology Research Institute Co., Ltd., Chengdu Sichuan 610303, China;
    2. State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan Liaoning 114009, China
  • Received:2021-10-19 Revised:2021-12-28 Online:2022-04-25 Published:2022-05-19

Abstract: Precipitation of σ phase in 2507 (S32750) super duplex stainless steel aged at 700-1000 ℃ for different time and its influence to impact property and corrosion resistance were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electrochemical workstation. The results show that the precipitation rate of σ phase is very fast in 2507 super duplex stainless steel, and the precipitation amount increases first and then decreases gradually with the extension of aging time. Precipitation of σ phase is the fastest after aging at 850-900 ℃, which leads to the serious reduction of impact toughness and corrosion resistance of the steel. It is recommended that the aging temperature should not be lower than 950 ℃.

Key words: 2507 super duplex stainless steel, σ phase, impact property, corrosion resistance

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