Effect of Zinc Addition Scenarios on General Corrosion of Alloy 690 in Borated and Lithiated Water at 330 °C

2021 ◽  
pp. 109627
Author(s):  
Dong-Seok Lim ◽  
Soon-Hyeok Jeon ◽  
Byung Joon Bae ◽  
Jinsoo Choi ◽  
Kyu Min Song ◽  
...  
CORROSION ◽  
2005 ◽  
Vol 61 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Y. Y. Chen ◽  
L. B. Chou ◽  
L. H. Wang ◽  
J. C. Oung ◽  
H. C. Shih

Abstract An experimental, potential-pH diagram was constructed for the nickel-based Alloy 690 (UNS N06690) in 25°C concentrated (5 M) sodium chloride (NaCl) solution, using an electrochemical hysteresis method. The domains of immunity, general corrosion, passivation, and pitting in 5-M NaCl solutions were defined. At pH > 4, the passive region subdivided into areas of perfect passivation, imperfect passivation, and pitting. After anodic polarization, the surface of each specimen was carefully examined metallographically. Pitting corrosion was observed over the entire pH range investigated (0.3 to 8.52), but general corrosion predominated at lower pH values (<3). On the other hand, the mechanical properties, such as ultimate tensile strength (UTS), strain at fracture, and the reduction area (RA) measured by the slow strain rate test (SSRT), decreased significantly at pH < 3. The SSRT results are consistent with fractography and side-view observations of the tested specimens by scanning electron microscopy (SEM).


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4105
Author(s):  
Soon-Hyeok Jeon ◽  
Dong-Seok Lim ◽  
Jinsoo Choi ◽  
Kyu-Min Song ◽  
Jong-Hyeon Lee ◽  
...  

The purpose of this work is to quantify the effects of dissolved zinc cations on corrosion and release rates from a pre-filmed Alloy 690 steam generator tubing material that was subsequently exposed to water containing zinc. The corrosion tests were performed in circulating 2 ppm Li and 1000 ppm B water without and with 60 ppb zinc at 330 °C. Gravimetric analyses and oxide characterization revealed that the corrosion rates, release rates, and oxide thicknesses decreased by subsequent exposure of the pre-filmed Alloy 690 to zinc. These benefits are attributed to the formation of a chromium-rich inner oxide layer incorporating zinc.


TAPPI Journal ◽  
2016 ◽  
Vol 15 (7) ◽  
pp. 467-477
Author(s):  
PASI NIEMELAINEN ◽  
MARTTI PULLIAINEN ◽  
JARMO KAHALA ◽  
SAMPO LUUKKAINEN

Black liquor high solids (about 80%) concentrators have often been found to suffer from aggressive corrosion. In particular, the first and second effect bodies are susceptible to corrosion attacks resulting in tube leaks and wall thinning, which limit the availability and lifetime of evaporator lines. Corrosion dynamics and construction materials have been studied extensively within the pulp and paper industry to understand the corrosion process. However, it has been challenging to identify root causes for corrosion, which has limited proactive measures to minimize corrosion damage. Corrosion of the first phase concentrator was studied by defining the potential regions for passive area, stress corrosion cracking, pitting corrosion, and general corrosion. This was achieved by using a technique called polarization scan that reveals ranges for the passive area in which the equipment is naturally protected against corrosion. The open circuit potential, also known as corrosion potential, and linear polarization resistance of the metal were monitored online, which allowed for definition of corrosion risks for stainless steel 304L and duplex stainless steels 2205 and SAF 2906. An online temperature measurement added insight to the analysis. A process diagnostics tool was used to identify root causes of the corrosion attacks. Many of the root causes were related to process conditions triggering corrosion. Once the metal surface was activated, it was difficult to repassivate the metal naturally unless a sufficient potential range was reached.


2014 ◽  
Vol 52 (9) ◽  
pp. 695-704
Author(s):  
Yun Soo Lim ◽  
Dong Jim Kim ◽  
Seong Sik Hwang
Keyword(s):  

1996 ◽  
Vol 451 ◽  
Author(s):  
Guen Nakayama ◽  
Yuichi Fukaya ◽  
Masatsune Akashi

ABSTRACTIn the scheme for geological disposal of high level radioactive nuclear wastes, the burial pit is to be isolated from the sphere of human life by a multiple-barrier system, which consists of an artificial barrier, composed of a canister, an overpack and a bentonite cushioning layer, and a natural barrier, which is essentially the bedrock. As the greatest as well as essentially the sole detriment to its integrity would be corrosion by groundwater. The groundwater comes to it seeping through the bentonite zone, thereby attaining conceivably the pH of transition from general corrosion to passivity, pHd, the behaviors of mild steel in such a groundwater environment have been examined. It has been shown that the pHd is lowered (enlargement of the passivity domain) with rising temperature and carbonate-bicarbonate concentration, while it is raised (enlargement of the general corrosion region) with increasing concentrations of chloride and sulfate ions.


2019 ◽  
Vol 16 (2) ◽  
Author(s):  
M. N. Setia Nusa

Water pipe of 4.5” diameter and has been operated for 8 year having failure due to corrosion attack on its external and internal surface. It is conducted failure analysis to find out the cause of corrosion by having testing examination of visual fractography, metalography,, SEM EDAX, hardness and chemical composition. Testing and examination results show that the failure / corroded pipe has a for in of general corrosion on the external surface due to environment factor or ground factor arround the pipe and on the internal surface was influenced by excessive root weld creating protrude which then causing turbolens and deposite to accelerate corrosion attack.Pipa berdiameter 4.5” yang berfungsi mengalirkan air bersih dan telah beroperasi selama 8 tahun, terjadi kerusakan berbentuk korosi pada permukaan luar pipa dan permukaan dalam. Untuk itu dilakukan analisa kerusakan untuk mengetahui penyebab terjadinya korosi dengan pengujian dan pemeriksaan secara visual,Fractography, Metallography, SEM, EDAX, Uji Kekerasan dan Uji Komposisi Kimia. Hasil pemeriksaan dan pengujian pada pipa yang rusak / korosi berbentuk jenis general korosi pada permukaan luar pipa yang diakibatkan faktor lingkungan atau tanah disekitar pipa, sedangkan pada bagian dalam pipa dipengaruhi oleh adanya lelehan pengelasan yang kurang sempurna sehingga menimbulkan benjolan yang mengakibatkan aliran air didalam pipa tidak lancar sehingga terjadi turbolensi yang menimbulkan endapan dan mengakibatkan percepatan terjadinya korosi.Keywords: Pipe, environtment, turbolens, corrosion, failure


Alloy Digest ◽  
1992 ◽  
Vol 41 (9) ◽  

Abstract INCONEL FILLER METAL 52 is a high chromium filler metal for gas-metal-arc and gas-tungsten-arc welding of Inconel Alloy 690 (See Alloy Digest Ni-266, March 1981). Higher chromium is beneficial in resisting stress-corrosion cracking in high purity water for pressurized water reactors and for resistance to oxidizing acids. This datasheet provides information on composition and tensile properties. It also includes information on corrosion resistance as well as joining. Filing Code: Ni-412. Producer or source: Inco Alloys International Inc..


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