Box-Behnken Design Approach Toward Predicting the Corrosion Response of 13Cr Stainless Steel

CORROSION ◽  
10.5006/3429 ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 356-365
Author(s):  
Mostafa Kazemipour ◽  
Salar Salahi ◽  
Ali Nasiri

13Cr stainless steel, the most commonly used oil country tubular good material with good mechanical and corrosion behavior, has the drawback of sensitivity to localized corrosion, particularly in offshore downhole environments, limiting the life span of the parts. A careful assessment of the corrosion behavior of the material can be done by the perception of the most influential environmental factors combined with the material’s intrinsic microstructure. This study aims to focus on the former, the effect of environmental factors, including pH, temperature, and chloride concentration, varying in the ranges of 4 to 7, 22°C to 80°C, and 1,000 mg/L to 22,000 mg/L, respectively, on the pitting corrosion behavior of 13Cr stainless steel. Adopting a response surface methodology, using a Box-Behnken design, a carefully designed set of corrosion tests at various combinations of the environmental factors were performed. Considering the pitting potential measured from the cyclic potentiodynamic polarization testing, as the response of each experiment, a quadratic model was developed correlating the studied environmental factors and the pitting potential values. Further analysis of the developed model was conducted through analysis of variance, followed by optimizing the model according to the highest, medium, and lowest pitting potentials. The optimized results confirmed that the best corrosion behavior occurs at approximately the lowest chloride concentration and temperature, and the highest pH value. However, contrary to the expectations, the worst corrosion response was detected at the medium temperature of 52°C, instead of the highest temperature of 80°C. It was concluded that at higher temperatures, the corrosion tends to be more uniform, resulting in the formation of a layer of corrosion products that covers the sample’s surface. The corrosion product layer acts as a barrier against the diffusion of the aggressive ions, causing deceleration of the corrosion reactions.

10.30544/384 ◽  
2011 ◽  
Vol 17 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Hamid Reza Asgari Bidhendi ◽  
Majid Pouranvari

Titanium alloys and stainless steel 316L are still the most widely used biomaterials for implants despite emerging new materials for this application. There is still someambiguity in corrosion behavior of metals in simulated body fluid (SBF). This paper aims at investigating the corrosion behavior of commercially pure titanium (CP-Ti), Ti–6Al–4V and 316LVM stainless steel (316LVM) in SBF (Hank’s solution) at37 ºC using the cyclic polarization test. Corrosion behavior was described in terms of breakdown potential, the potential and rate ofcorrosion, localized corrosion resistance, andbreakdown repassivation. The effects of anodizing on CP-Ti samples and the passivation on the 316LVM were studied in detail. It was shown that CP-Ti exhibited superior corrosion properties compared to Ti–6Al–4V and 316LVM.


CORROSION ◽  
10.5006/3779 ◽  
2021 ◽  
Author(s):  
Yoon Hwa ◽  
Christopher Kumai ◽  
Nancy Yang ◽  
Joshua Yee ◽  
Thomas Devine

The localized corrosion of laser surface melted (LSM) 316L stainless steel is investigated by a combination of potentiodynamic anodic polarization in 0.1M HCl and microscopic investigation of the initiation and propagation of localized corrosion. The pitting potential of LSM 316L is significantly lower than the pitting potential of wrought 316L. The LSM microstructure is highly banded as a consequence of the high laser power density and high linear energy density. The bands are composed of zones of changing modes of solidification, cycling between very narrow regions of primary austenite solidification and very wide regions of primary ferrite solidification. Pits initiate in the outer edge of each band where the mode of solidification is primary austenite plane front solidification and primary austenite cellular solidification. The primary austenite regions have low chromium concentration (and possibly low molybdenum concentration), which explains their susceptibility to pitting corrosion. The ferrite is enriched in chromium, which explains the absence of pitting in the primary ferrite regions. The presence of the low chromium regions of primary austenite solidification explains the lower pitting resistance of LSM 316L relative to wrought 316L. The influence of banding on localized corrosion is applicable to other rapidly solidified processes such as additive manufacturing.


2017 ◽  
Vol 15 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Davide Prando ◽  
Andrea Brenna ◽  
Fabio M. Bolzoni ◽  
Maria V. Diamanti ◽  
Mariapia Pedeferri ◽  
...  

Background Titanium has outstanding corrosion resistance due to the thin protective oxide layer that is formed on its surface. Nevertheless, in harsh and severe environments, pure titanium may suffer localized corrosion. In those conditions, costly titanium alloys containing palladium, nickel and molybdenum are used. This purpose investigated how it is possible to control corrosion, at lower cost, by electrochemical surface treatment on pure titanium, increasing the thickness of the natural oxide layer. Methods Anodic oxidation was performed on titanium by immersion in H2SO4 solution and applying voltages ranging from 10 to 80 V. Different anodic current densities were considered. Potentiodynamic tests in chloride- and fluoride-containing solutions were carried out on anodized titanium to determine the pitting potential. Results All tested anodizing treatments increased corrosion resistance of pure titanium, but never reached the performance of titanium alloys. The best corrosion behavior was obtained on titanium anodized at voltages lower than 40 V at 20 mA/cm2. Conclusions Titanium samples anodized at low cell voltage were seen to give high corrosion resistance in chloride- and fluoride-containing solutions. Electrolyte bath and anodic current density have little effect on the corrosion behavior.


CORROSION ◽  
10.5006/3516 ◽  
2020 ◽  
Vol 76 (12) ◽  
Author(s):  
Salar Salahi ◽  
Mostafa Kazemipour ◽  
Ali Nasiri

This study aims to understand the correlation between the manufacturing process-induced plastic deformation, microstructure, and corrosion behavior of a 13Cr martensitic stainless steel tubing material (UNS S42000). Comparisons were made between the microstructure, crystallographic orientation, and corrosion performance of a texture-free, heat-treated sample and uniaxially tensioned samples to the elongations of 5% and 22%. Cyclic potentiodynamic polarization tests and electrochemical impedance spectroscopy were performed on all samples in aerated 3.5 wt% NaCl electrolyte at room temperature. Overall, the corrosion resistance of the samples was found to decrease with increasing deformation level. A more stable and higher corrosion potential and pitting potential values with a better stability of the passive film were derived for the nondeformed sample, whereas the 5% and 22% elongated samples exhibited lower corrosion and pitting potential values and were characterized by having a less stable passive layer. All samples consistently revealed micropit formation on the lath boundaries where a high concentration of chromium carbide precipitates was detected. Increasing the level of plastic strain in 13Cr stainless steel was found to enlarge the size of sensitized regions along the matrix/coarse chromium carbide precipitates interface, leading to more regions susceptible to initiation and propagation of pitting.


Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 529 ◽  
Author(s):  
Federica Zanotto ◽  
Vincenzo Grassi ◽  
Andrea Balbo ◽  
Fabrizio Zucchi ◽  
Cecilia Monticelli

This paper reports the effects of thermal aging between 650 and 850 °C on the localized corrosion behavior of lean duplex stainless steel (LDSS 2404). Critical pitting temperature (CPT) and double loop electrochemical potentiokinetic reactivation (DL-EPR) tests were performed. The localization of pitting attack and intergranular corrosion (IGC) attack after DL-EPR was investigated by optical (OM) and scanning electron microscopy (SEM) and by focused ion beam (FIB) coupled to SEM. Thermal aging caused the precipitation of mainly chromium nitrides at grain boundaries. Aging at 650 °C or short aging times (5 min) at 750 °C caused nitride precipitation mainly at α/α grain boundaries as a result of fast diffusion of chromium in this phase. Aging at 850 °C or aging times from 10 to 60 min at 750 °C also allowed the precipitation at the α/γ interface. Nitrides at γ/γ grain boundaries were observed rarely and only after long aging times (60 min) at 850 °C. Electrochemical tests showed that in as-received samples, pitting attack only affected the α phase. Conversely, in aged samples, pitting and IGC attack were detected close to nitrides in correspondence of α/α and α/γ grain boundaries depending on aging temperatures and times.


2011 ◽  
Vol 347-353 ◽  
pp. 3135-3138
Author(s):  
Hong Hua Ge ◽  
Jie Ting Tao ◽  
Xiao Ming Gong ◽  
Cheng Jun Wei ◽  
Xue Min Xu

Abstract: The effect of electromagnetic treatment on corrosion behavior of carbon steel and stainless steel in simulated cooling water was investigated by electrochemical impedance spectroscopy, potentiodynamic polarization techniques and water analysis. It was found that the charge transfer resistance decreased and the corrosion current density increased after electromagnetic treatment for carbon steel electrode, which shows that such treatment promotes corrosion of carbon steel in simulated cooling water. In contrast, the pitting potential of 316L stainless steel electrode rose which revealed that electromagnetic treatment of the experimental water exhibited corrosion inhibition to 316L stainless steel. Reasons for different corrosion behavior of the two metals were discussed.


2020 ◽  
Vol 856 ◽  
pp. 135-142
Author(s):  
Rachapong Tangkwampian ◽  
Pornsak Srisungsitthisunti ◽  
Siriporn Daopiset ◽  
Pruet Kowitwarangkul

This paper investigates the effect of fiber laser surface modification of AISI 316L austenitic stainless steel on corrosion behavior. In the experiments, the fiber laser with center wavelength of 1062 nm was employed with various laser parameters of beam velocity and laser frequency. The laser-treated has performed on the specimen surface in order to form the melted layer with an argon gas shielding. The electrochemical tested results showed that the laser-treated increases 40% pitting potential. Moreover, the results also exhibited corrosion potential shift to more positive potential. On the basis of the findings on the corrosion improvement, it can be concluded that the pitting potential of the material can be improved by a corrosion protective layer from the new laser-treated surface.


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