Effect of the Flow Velocity on the Corrosion Behavior of UNS S41426 Stainless Steel in the Extremely Aggressive Oilfield Environment for the Tarim Area

CORROSION ◽  
10.5006/2813 ◽  
2020 ◽  
Vol 76 (7) ◽  
pp. 654-665 ◽  
Author(s):  
Yang Zhao ◽  
Limin Chang ◽  
Tao Zhang ◽  
Junfeng Xie ◽  
Yan Chen ◽  
...  

Effect of flow velocity on the passive film and pitting corrosion behavior of UNS S41426 stainless steel (SS) under the extreme oilfield environment was investigated using different techniques such as microscopy, nanoindentation, and electrochemical techniques. The experimental results show that the corrosion rate of UNS S41426 SS increased with velocity. The increase in flow velocity decreased the thickness and content of amorphous Cr(OH)3 (s) in the film. This in turn increased the density of phase boundary, resulting in a higher defect density. Thus, the UNS S41426 SS film became susceptible to breaking. Furthermore, the pitting had a higher susceptibility to grow to a larger size both in the vertical and horizontal directions with the increase in flow velocity.

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
G. Salinas ◽  
J. G. Gonzalez-Rodriguez ◽  
J. Porcayo-Calderon ◽  
V. M. Salinas-Bravo ◽  
M. A. Espinoza-Medina

The hot corrosion behavior of Fe40Al intermetallic alloyed with Ag, Cu, Li, and Ni (1–5 at.%) in NaCl-KCl (1 : 1 M) at 670°C, typical of waste gasification environments, has been evaluated by using polarization curves and weight loss techniques and compared with a 304-type stainless steel. Both gravimetric and electrochemical techniques showed that all different Fe40Al-base alloys have a much higher corrosion resistance than that for stainless steel. Among the different Fe40Al-based alloys, the corrosion rate was very similar among each other, but it was evident that the addition of Li decreased their corrosion rate whereas all the other elements increased it. Results have been explained in terms of the formation and stability of an external, protective Al2O3layer.


2021 ◽  
Vol 63 (6) ◽  
pp. 505-511
Author(s):  
Songkran Vongsilathai ◽  
Anchaleeporn Waritswat Lothongkum ◽  
Gobboon Lothongkum

Abstract A new duplex 25Cr-3Ni-7Mn-0.66 N alloy was prepared in a vacuum arc re-melting furnace and characterized by metallographic and EPMA methods. Its corrosion behavior was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and a Mott-Schottky (M-S) analysis in artificial seawater at room temperature and compared with those of super and normal commercial duplex stainless steel (SDSS and DSS). No significant difference in the open circuit potentials and pitting potentials was observed. Its passive film current density lies between those of SDSS and DSS. This was confirmed by EIS analysis. A pit attack was observed on the δ-phase for all duplex samples, because the PREN16 of the δ-phase was lower than that of the γ-phase. From the Mott-Schottky analysis, the passive films were found to be composed of bi-layer structures, a p-type semiconductor inner layer, and a n-type semiconductor outer layer. The degree of defect as well as the effect of nitrogen in passive film layer are discussed with respect to the point defect model.


CORROSION ◽  
10.5006/2558 ◽  
2017 ◽  
Vol 74 (5) ◽  
pp. 543-550 ◽  
Author(s):  
Luiza Esteves ◽  
Mônica M.A.M. Schvartzman ◽  
Wagner Reis da Costa Campos ◽  
Vanessa F.C. Lins

Specimens of lean duplex and duplex stainless steel were exposed at 200°C in industrial white liquor from a Brazilian kraft mill using an autoclave to simulate the same conditions of digester processing. Tafel extrapolation method and weight loss were used to evaluate corrosion behavior of duplex steel in white liquor. The higher alloy steel, although presenting a lower corrosion rate than the lean duplex, presents a more severe selective attack on ferrite, at 200°C and 1.8 MPa, after Tafel extrapolation method in industrial white liquor.


2019 ◽  
Vol 22 (suppl 1) ◽  
Author(s):  
Stephania Cappellari de Rezende ◽  
Isabela Dainezi ◽  
Raíra Chefer Apolinario ◽  
Lucíola Lucena de Sousa ◽  
Neide Aparecida Mariano

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