Synergistic Erosion–Corrosion Behavior of X-65 Carbon Steel at Various Impingement Angles

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
A. Pasha ◽  
H. M. Ghasemi ◽  
J. Neshati

A slurry impingement rig containing 6 wt.% SiO2 particles was used to investigate synergistic erosion–corrosion behavior of X-65 carbon steel at various impingement angles. Maximum erosion–corrosion and erosion rates occurred at impingement angles of about 25 deg and 40–55 deg, respectively. The synergy value highly depended on the impingement angle. The formation of patches of porous corrosion product followed by the formation of corrosion pits led to a positive synergy under impingement angle of 25 deg. At higher impingement angles, the absence of pits probably due to the formation of a more durable tribocorrosion layer resulted in a negative synergy.

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3898 ◽  
Author(s):  
Rehan Khan ◽  
Hamdan H. Ya ◽  
William Pao ◽  
Armaghan Khan

Erosion–corrosion in flow changing devices as a result of sand transportation is a serious concern in the hydrocarbon and mineral processing industry. In this work, the flow accelerated erosion–corrosion mechanism of 90°, 60°, and 30° long radius horizontal–horizontal (H–H) carbon steel elbows with an inner diameter of 50.8 mm were investigated in an experimental closed-flow loop. For these geometrical configurations, erosion–corrosion was elucidated for erosive slug flow regimes and the extent of material degradation is reported in detail. Qualitative techniques such as multilayer paint modeling and microscopic surface imaging were used to scrutinize the flow accelerated erosion–corrosion mechanism. The 3D roughness characterization of the surface indicates that maximum roughness appears in downstream adjacent to the outlet of the 90° elbow. Microscopic surface imaging of eroded elbow surfaces disseminates the presence of corrosion pits on the exit regions of the 90° and 60° elbows, but erosion scars were formed on the entry regions of the 30° elbow. Surface characterization and mass loss results indicated that changing the elbow geometrical configuration from a small angle to wide angle significantly changed the mechanical wear mechanism of the tested elbows. Moreover, the maximum erosive location was identified at the top of the horizontally-oriented elbow for slug flow.


2008 ◽  
Vol 373-374 ◽  
pp. 456-459
Author(s):  
Li Whu Jiang ◽  
G. Cao ◽  
Xu Hui Mao ◽  
Fu Xing Gan

In China’s freshwater environment, the eutrophication phenomenon has become more and more serious in recent years. The changes of water quality may induce the variation of metal’s corrosion behavior. In this paper, carbon steel as common material of hydraulic structure was the investigated object, and its early corrosion behavior affected by microbes (algae and microbe) in eutrophic lakes was studied using immersion test, electrochemical measurements and infra-red spectrometry techniques. The experimental waters were natural eutrophic water and microbescleaned water. The former was fetched from eutrophic East Lake in Wuhan City, Hubei Province of China, and the preparation of later was making natural eutrophic water sterilized and algae removed by UV radiation. In order to present the changes of carbon steel’s corrosion behavior in natural eutrophic freshwater with and without microbes, comparative experiments were conducted in lab. Both weight loss method and electrochemical techniques showed that, the corrosion rates of carbon steel decreased in early stage for the influence of microbe existence. The analysis of infrared spectra indicated that, corrosion product on the surface of coupons taken from natural eutrophic water, mainly were δ hydroxyl ferric oxide, magnetic iron ore, γ hydroxyl ferric oxide, α hydroxyl ferric oxide and β hydroxyl ferric oxide, with relative concentration ratio of 1:0.314:1.003:0.634: 0.654. While corrosion product on the surface of carbon steel taken from the microbes-cleaned water, mainly were α hydroxyl ferric oxide and γ hydroxyl ferric oxide, with relative concentration ratio of 1:1.215.


2013 ◽  
Vol 815 ◽  
pp. 55-60
Author(s):  
Yun Ma ◽  
Qian Wang ◽  
Xin Min Wu

The corrosion behavior of commonly-used steels in the oil-containing and alcoholic sewage from gas field was studied combined with polarization curves, electric impedance spectrum (EIS), dynamic corrosion weight loss test, scanning electron microscope (SEM) and energy spectrum (ES) of corrosion products. It was shown that corrosion rate increased with the sequence of 316L, 16Mn, 20#, L360 and 20R steels, and 316L steel was corroded more slightly than 16Mn, 20#, L360 and 20R steels. There were some spot corrosion pits on the surface of L360 and 20R steels. A higher Chromium content of 316L steel led to a stronger corrosion resistance. Ferrous carbonate was the mainly corrosion product on the surface of the four steels. While the corrosion product on the surface of L360 and 20R steels was poor adhered and easy to fall off, and formed some corrosion pits on the steels surface.


Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1283
Author(s):  
Jingjiu Yuan ◽  
Chaoyi Chen ◽  
Junqi Li ◽  
Bianli Quan ◽  
Yuanpei Lan ◽  
...  

When alumina is produced by the Bayer process with high-sulfur bauxite, the sulfur would strongly corrode the 12Cr1MoV steel made heat exchanger. This study investigated the initial corrosion behavior of the 12Cr1MoV steel exposed to a thiosulfate-containing sodium aluminate (TCSA) solution under the evaporation conditions of alumina production. The obtained corrosion rate equation is V = 6.306·t·exp(−0.71). As corrosion progressed, with the corrosion product film growing, the corrosion current density declines slowly, and the corrosion resistance of the steel is increased. At 1–3 days, the corrosion product film consisted of FeO, Fe2O3, and FeOOH. S2O32− lead to corrosion in local areas of the steel and pits appeared. AlO2− is transformed into Al(OH)3 and filled in the corrosion pits. At 4 and 5 days, Fe3O4 is generated in the outermost layer, and Al(OH)3 is shed from the corrosion pits. The corrosion mechanism of 12Cr1MoV steel in a TCSA solution is proposed based on the experimental results.


1994 ◽  
Vol 353 ◽  
Author(s):  
Yoichi Kojima ◽  
Toshinobu Hioki ◽  
Shigeo Tsujikawa

AbstractThe use of bentonite as buffer and carbon steel as overpack material for the geological disposal of nuclear waste is under investigation. To better assess the long term integrity of the carbon steel overpack, a quantitative analysis of the corrosion behavior on the steel surface for time frames beyond that of feasible empirical determination is required. The state n years after disposal, consisting of Carbon Steel / Corrosion Products + Bentonite / Water, was simulated and the corrosion behavior of the carbon steel in this state investigated. The following facts became apparent. Both the corrosion rate and the non-uniformity of it increased with increase in the corrosion product content in the compacted bentonite. When the corrosion product layer was formed between the carbon steel and the bentonite, it ennobled the corrosion potential and increased the corrosion rate.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1152
Author(s):  
Charles Rasse ◽  
Nicolas Mary ◽  
Hiroshi Abe ◽  
Yutaka Watanabe ◽  
Bernard Normand

Erosion-corrosion behavior of piping systems is a critical issue for their durability. This work concerns the erosion-corrosion behavior of carbon steel as a function of abradant characteristics as particle size and concentration. Degradation tests were performed in a jet erosion-corrosion cell with a maximum flow rate of 4.8 m/s, and jet angles comprised 30° and 90°. Abradant particles consisted of angular alumina powder with a mean diameter of 181, 219, and 359 µm. A critical threshold flow velocity of about 2.5 m/s was determined when experiments were performed with particles with diameters of 181 µm and jet angles of 45°. Even if erosion did not occur, the degradation rate increased compared with the stagnant condition because of dissolved dioxygen supply. A maximum of erosion-corrosion of 4 mg × cm−2 × h−1 was determined for the jet angle of 45°, irrespective of the particle sizes. The increase of abradant concentration led to a higher degradation rate regardless of the jet angle. However, the degradation rates tended to limit values of 7 mg × cm−2 × h−1 at 45° and 5 mg × cm−2 × h−1 at 90°. Above a critical concentration, a slowdown of the degradation was measured, suggesting that particle behavior in dense fluid acts on material degradation. This critical concentration can be understood from the interactions of the particles in concentrated media that modify trajectories in the flow and at the metal surface, reducing their kinetic energy consequently.


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