The pitting corrosion of thermally aged Z3CN20.09M cast duplex stainless steel (CDSS) was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy. Both pitting potential and charge transfer resistance values of thermally aged specimens became less positive with aging time, while passive current density increased, indicating that thermal aging causes degradation in pitting corrosion resistance. The pitting potential of thermally aged specimens after annealed is higher than that of thermally aged specimens revealing that the pitting corrosion resistance of annealed specimens has been improved. The α’ phase precipitation during thermal aging in ferrite brings the Cr-enriched and Cr-depleted zone microstructures which mainly induced the degradation of pitting corrosion resistance. The microsegregation of Cr element or Cr enriched and Cr-depleted zones will be alleviated or even removed due to the Cr-rich α’ phases dissolution during the process of annealing. So, the pitting corrosion resistance of annealed specimens is improved.
ParkJSYoonYK.Evaluation of thermal aging embrittlement of duplex stainless steels by electrochemical method. Scripta Metall Mater. 1995; 32: 1163–1168. doi: 10.1016/0956-716X(95)00119-G
2.
XueFWangZXShuGG. Thermal aging effect on Z3CN20.09M cast duplex stainless steel. Nucl Eng Des. 2009; 239: 2217–2223. doi: 10.1016/j.nucengdes.2009.06.009
3.
YiYSShojiT.Detection and evaluation of material degradation of thermally aged duplex stainless steels: electrochemical polarization test and AFM surface analysis. J Nucl Mater. 1996; 231: 20–28. doi: 10.1016/0022-3115(96)00361-3
4.
ChopraOKChungHM.Aging of cast duplex stainless steels in LWR systems. Nucl Eng Des. 1985; 89: 305–318. doi: 10.1016/0029-5493(85)90069-X
5.
MathewMDLietzanLMMurtyKL. Low temperature aging embrittlement of CF-8 stainless steel. Mater Sci Eng A. 1999; 269: 186–196. doi: 10.1016/S0921-5093(99)00140-9
6.
LiSWangYWangX. G-phase precipitation in duplex stainless steels after long-term thermal aging: a high-resolution transmission electron microscopy study. J Nucl Mater. 2014; 452: 382–388. doi: 10.1016/j.jnucmat.2014.05.069
7.
LoKHShekCHLaiJKL.Recent developments in stainless steels. Mater Sci Eng R. 2009; 65: 39–104. doi: 10.1016/j.mser.2009.03.001
8.
PareigeCNovySSailletS. Study of phase transformation and mechanical properties evolution of duplex stainless steels after long term thermal ageing (20 years). J Nucl Mater. 2011; 411: 90–96. doi: 10.1016/j.jnucmat.2011.01.036
9.
ChandraKSinghalRKainV. Low temperature embrittlement of duplex stainless steel: correlation between mechanical and electrochemical behavior. Mater Sci Eng A. 2010; 527: 3904–3912. doi: 10.1016/j.msea.2010.02.069
10.
IacovielloFCasariFGialanellaS.Effect of “475°C embrittlement” on duplex stainless steels localized corrosion resistance. Corros Sci. 2005; 47: 909–922. doi: 10.1016/j.corsci.2004.06.012
11.
TavaresSSMTerraVF.Corrosion resistance evaluation of the UNS S31803 duplex stainless steels aged at low temperature (350 to 550°C) using DLEPR tests. J Mater Sci. 2005; 40: 4025–4028. doi: 10.1007/s10853-005-1993-9
12.
YaoYHWeiJFWangZP.Effect of long-term thermal aging on the mechanical properties of casting duplex stainless steels. Mater Sci Eng A. 2012; 551: 116–121. doi: 10.1016/j.msea.2012.04.105
13.
BergHP.Corrosion mechanisms and their consequences for nuclear power plants with light water reactors. Reliab Risk Anal Theory Appl. 2009; 2: 57–68.
14.
ParkCJKwonHS.Effects of aging at 475 °C on corrosion properties of tungsten-containing duplex stainless steels. Corros Sci. 2002; 44: 2817–2830. doi: 10.1016/S0010-938X(02)00079-3
15.
LoKHKwokCTChanWK. Corrosion resistance of duplex stainless steel subjected to long-term annealing in the spinodal decomposition temperature range. Corros Sci. 2012; 55: 267–271. doi: 10.1016/j.corsci.2011.10.027
16.
LiSLZhangHLWangYL. Annealing induced recovery of long-term thermal aging embrittlement in a duplex stainless steel. Mater Sci Eng A. 2013; 564: 85–91. doi: 10.1016/j.msea.2012.11.046
17.
YamadaTOkanoSKuwanoH.Mechanical property and microstructural change by thermal aging of SCS14A cast duplex stainless steel. J Nucl Mater. 2006; 350: 47–55. doi: 10.1016/j.jnucmat.2005.11.008
18.
LiSLWangYLZhangHL. Microstructure evolution and impact fracture behaviors of Z3CN20-09M stainless steels after long-term thermal aging. J Nucl Mater. 2013; 433: 41–49. doi: 10.1016/j.jnucmat.2012.09.004
19.
FrankelGS.Pitting corrosion of metals: a review of the critical factors. J Electrochem Soc. 1998; 145: 2186–2198. doi: 10.1149/1.1838615
20.
WangYQLiNYangB.Effect of ferrite on pitting corrosion of Fe20Cr9Ni cast austenite stainless steel for nuclear power plant pipe. Br Corros Eng Sci Technol. 2015; 50: 330–337. doi: 10.1179/1743278214Y.0000000229
21.
ZhangLHZhangWJiangYM. Influence of annealing treatment on the corrosion resistance of lean duplex stainless steel 2101. Electrochim Acta. 2009; 54: 5387–5392. doi: 10.1016/j.electacta.2009.04.023
22.
VrinatMCozarRMeyzaudY.Precipitated phases in the ferrite of aged cast duplex stainless steels. Scripta Metall. 1986; 8: 1101–1106. doi: 10.1016/0036-9748(86)90183-3
23.
AhnYSKimJMJeongBH.Effect of aging treatments and microstructural evolution on corrosion resistance of tungsten substituted 2205 duplex stainless steel. Mater Sci Technol. 2002; 18: 383–388. doi: 10.1179/026708302225001642
24.
WangYQYangBHanJ. Effect of precipitated phases on the pitting corrosion of Z3CN20.09M cast duplex stainless steel. Mater Trans. 2013; 54: 839–843. doi: 10.2320/matertrans.M2012410
25.
LiWSCuiNLuoJL.Pitting initiation and propagation of hypoeutectoid iron-based alloy with inclusions of martensite in chloride-containing nitrite solutions. Electrochim Acta. 2004; 49 (9-10): 1663–1672. doi: 10.1016/S0013-4686(03)01014-4
26.
OlssonCOALandoltD.Passive films on stainless steels – chemistry, structure and growth. Electrochim Acta. 2003; 48: 1093–1104. doi: 10.1016/S0013-4686(02)00841-1
27.
OlefjordIElfstromB.The composition of the surface during passivation of stainless steels. Corrosion. 1982; 38: 46–52. doi: 10.5006/1.3577318
28.
HorvathaJUhligHH.Critical potentials for pitting corrosion of Ni, Cr-Ni, Cr-Fe, and related stainless steels. J Electrochem Soc. 1968; 115 (8): 791–795. doi: 10.1149/1.2411433
29.
LiSLWangYLLiSX. Effect of long term aging on the microstructure and mechanical properties of cast austenitic stainless steels. Acta Metall Sin. 2010; 46: 1186–1191. doi: 10.3724/SP.J.1037.2010.01186
30.
ChungHMChopraOK.Kinetics and mechanism of thermal aging embrittlement of duplex stainless steels. Proceedings of the International symposium on Environmental Degradation of Materials in Nuclear Power Systems: Water Reactors; 1987, Traverse City, MI. p. 1-32.
31.
ChungHM.Aging and life prediction of cast duplex stainless steel components. Int J Press Ves Pip. 1992; 50: 179–213. doi: 10.1016/0308-0161(92)90037-G
