Corrosion Interaction of 9%Cr Ferritic/Martensitic Steels at 450 and 550 °C With Flowing Pb–Bi Eutectic Containing 10−7 Mass % Dissolved Oxygen

Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys

Corrosion behavior of 9%Cr F/M P92, E911, and EUROFER steels was investigated in flowing (2 m/s) Pb–Bi with 10−7 mass % O at 450 and 550 °C for up to 8766 and 2011 h, respectively. The steels show mixed corrosion modes simultaneously revealing protective scale formation, accelerated oxidation, and solution-based attack. At 450 °C, the accelerated oxidation resulted in a metal recession averaging 6 μm (± 2 μm) after ∼ 8766 h, while local solution-based corrosion attack ranged from ∼40 to 350 μm. At 550 °C, the accelerated oxidation resulted in a metal recession of about 10 μm (± 2 μm) after ∼ 2011 h. Solution-based corrosion attack appears more regularly at 550 °C, with a maximum depth ranged from ∼90 to 1000 μm. The incubation time for the solution based attack at 450 °C is 500–2000 h and < 300 h at 550 °C.

Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys

Corrosion behavior of 9 %Cr ferritic/martensitic (F/M) P92, E911 and EUROFER steels was investigated in flowing (2 m/s) Pb-Bi with 10−7 mass%O at 450 and 550 °C for up to 8766 and 2011 h, respectively. The steels show mixed corrosion modes simultaneously revealing protective scaling, accelerated oxidation and solution-based attack. At 450 °C, the accelerated oxidation resulted in a metal recession averaging 6 μm (± 2 μm) after ∼8766 h while local solution-based corrosion attack ranged from ∼40 to 350 μm. At 550 °C, the accelerated oxidation resulted in a metal recession of about 10 μm (± 2 μm) after ∼2011 h. Solution-based corrosion attack appears more regularly at 550 °C, with a maximum depth ranged from ∼90 to 1000 μm. Incubation time for solution based attack is 500–2000 h for 450 °C and < 300 h for 550 °C. The EUROFER steel showed more severe metal recession via both oxidation and solution-based corrosion in comparison with P92 and E911 steels. The possible effect of alloying and structure on the corrosion response of 9 %Cr F/M steels is discussed.


2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys

The effect of structural state (solution annealed (SA) and after 40% cold work (CW)) and surface finishing (turning, grinding, and polishing) on the corrosion behavior of austenitic 1.4970 (15-15 Ti) steel in flowing (2 m/s) Pb-Bi eutectic containing 10−7 mass% dissolved oxygen at 400 °C and 10−6 mass% O at 500 °C is investigated. At 400 °C for ∼13,000 h, the corrosion losses are minor for steel in both structural states and for surfaces finished by turning and grinding—a thin Cr-based oxide film is formed. In contrast, the polished surface showed initiation of solution-based corrosion attack with the formation of iron crystallites and preferential propagation along the grain boundaries. The depth of corrosion attack does not exceed 10 μm after ∼13,000 h. At 500 °C for 2000 h, the samples in both structural states showed general slight oxidation. Cold-worked steel underwent a severe groove-type and pit-type solution-based attack of 170 μm in maximum depth, while the SA sample showed only sporadic pit-type corrosion attack to the depth of 45 μm in maximum.


2020 ◽  
Vol 532 ◽  
pp. 152079
Author(s):  
Ping Lai ◽  
Junqiang Lu ◽  
Hao Zhang ◽  
Qingdong Liu ◽  
Qifeng Zeng ◽  
...  

2020 ◽  
Vol 166 ◽  
pp. 108432 ◽  
Author(s):  
Ziqiang Dong ◽  
Ming Li ◽  
Yashar Behnamian ◽  
Jing-Li Luo ◽  
Weixing Chen ◽  
...  

2016 ◽  
Vol 835 ◽  
pp. 115-120
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena

All materials which are intended to have in contact with food and other commodities produced or processed for human consumption are called food contact materials (FCM’s). Stainless steel (SS) – a widely known metallic FCM is used mainly in processing equipment, containers and household utensils. It is known for having numerous industrial and domestic applications worldwide due to its special characteristics of having notable corrosion resistance. However, this corrosion resistance is not all-encompassing since SS may still undergo degradation when subjected to a specific corrosion-inducing environment. SS may be classified according to its microstructure. If the atoms which make up the SS can be viewed as having a face-centered cubic structure, then the alloy is said to be austenitic. This SS grades include the conventional 300-series and the newly-developed 200-series. The former has superior corrosion resistance while the latter is far cheaper. In this study, the corrosion behavior of AISI 202 SS in two different levels of dissolved oxygen (O2) and three acid concentrations was investigated using electrochemical techniques, namely, open-circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS). As the concentration of citric acid is increased, the measured OCP values of the alloy decreased and the polarization resistance (Rp) decreased, indicating decrease in alloy stability and decline in the corrosion resistance, respectively. With regards to effects of dissolved O2, results revealed that increasing the level of dissolved O2 has consequently increased the polarization resistance and shifted the OCP to more positive values. All the generated Nyquist plots exhibited a depressed capacitive loops indicating that corrosion in the designated solution occurred with charge transfer as the rate-determining step.


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