Microstructure and flow accelerated corrosion resistance of Cr coatings electrodeposited in a trivalent chromium bath

Author(s):  
Ying Wang ◽  
Yanhong Liu ◽  
Guangbin Li ◽  
Mingmin Zheng ◽  
Yusha Li ◽  
...  
2021 ◽  
Vol 122 ◽  
pp. 105127
Author(s):  
P. Madasamy ◽  
M. Mukunthan ◽  
P. Chandramohan ◽  
T.V. Krishna Mohan ◽  
Andrews Sylvanus ◽  
...  

Author(s):  
Dong-Jin Kim ◽  
Sung-Woo Kim ◽  
Jong Yeon Lee ◽  
Kyung Mo Kim ◽  
Se Beom Oh ◽  
...  

Author(s):  
Ali Keshavarz ◽  
Andrew K. Ali ◽  
Randy K. Lall

Flow-accelerated corrosion (FAC) is a phenomenon that results in metal loss from piping, vessels and equipment made of carbon steel. This metal loss can lead to stress to occur at the steam inlet nozzle side, where it is located at the side of the deaerator. This paper presents a method to find the thickness critical of the steam inlet nozzle. A Finite Element (FE) model of the pressure vessel head was created to perform a stress analysis using NX Nastran 5.0. By applying materials properties, loads and constraints to the model, the results obtained are required to satisfy the following criterion: vonMises≥SySy=YieldStrength The results obtained from the stress analysis were analyzed to obtain a corrosion allowance and it was compared to the recommended value from a normal deaerator design, which is roughly 0.25 inches. From the FE model, and by continuously reducing the thickness of the nozzle, it was determined that the corrosion allowance is 0.229 inches, and that the percentage error was 8.4%.


2018 ◽  
Vol 25 (7) ◽  
pp. 779-787 ◽  
Author(s):  
Yong Li ◽  
Min-dong Chen ◽  
Jian-kuan Li ◽  
Long-fei Song ◽  
Xin Zhang ◽  
...  

Author(s):  
Yogendra S. Garud

Wall thinning in pressure retaining components, especially due to the flow-accelerated corrosion, has been a significant factor affecting the safety and unplanned system downtimes. On the other hand, overestimating the impact of possible wall thinning often leads to unnecessary or expensive inspections and replacements. The simplified or quick (short-cut) methods of analysis and prediction often lack the requisite degree of accuracy and confidence. This paper presents a few techniques for better analysis of the wall thinning data to address these issues. These techniques make use of the statistical methods, pattern recognition, and optimization to perform a robust data filtering and thinning rate estimation that accounts for measurement uncertainty. The techniques are discussed with application to a large database and an inspection program. The impact of these analytical improvements is presented in comparison with results of the simplified method of analysis. The results include both the margin on remaining life and the projected wall thinning rates, with implications for inspections.


Author(s):  
Khaled Sobhan ◽  
Francisco Martinez ◽  
D.V. Reddy

The corrosion resistance of fly ash-based geopolymer structural concrete (GPC), with or without fibers, was investigated in a simulated marine environment, and compared with that of ordinary Portland cement structural concrete. The corrosion behavior is studied through an electrochemical method for inducing accelerated corrosion. The fiber-reinforced specimens contained polyolefin fibers in the amounts of 0.1%, 0.3%, and 0.5% by volume. Several artificial corrosion conduits were introduced into the specimens reaching up to the rebars. This process enhanced the rate of laboratory corrosion in GPC. The corrosion-damaged beams were then analyzed through a method of crack scoring, and determination of steel mass loss and residual flexural load capacity. The fiber-reinforced corroded GPC beams showed a 24% reduction in crack scores, and a 109% increase in residual flexural load capacity, compared to unreinforced corroded GPC beams. This shows promise of fiber-reinforced GPC as a sustainable structural material in the marine environment.


2017 ◽  
Vol 13 (10) ◽  
pp. 5905-5913
Author(s):  
S. Saravanan ◽  
P.Senthil Kumar ◽  
T. Palanisamy ◽  
M. Ravichandran ◽  
V. Anandakrishnan ◽  
...  

AA6063-TiC composites have several weight percentages up to 9 wt. % were fabricated by using stir casting route method. The effects of the weight percentage of TiC particles on the microstructures and corrosion behavior of AA6063-TiC composites were studied. The results revealed that the AA6063-TiC composites exhibited higher density than the AA6063 matrix. The accelerated corrosion tests of AA6063-TiC composites in 3.5 wt. % NaCl aqueous solution at room temperature, the AA6063-TiC composites have better corrosion resistance than the AA6063 matrix. Increasing the weight percentage of the TiC particles to reduces the corrosion rate of the AA6063-TiC composites. In this process corrosion rate of 0.4402 mm/year for AA6063 matrix, 0.3891 mm/year for 3 wt. % , 0.3568 mm/year for 6 wt. % and 0.3062 mm/year for 9 wt. % of TiC particles respectively. The poor corrosion resistance of the composites can be attributed to the galvanic effects between the AA6063 matrix and TiC reinforcement.


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