Variability in Section Loss and Maximum Pit Depth of Corroded Prestressing Wires

2021 ◽  
pp. 491-498
Author(s):  
Lorenzo Franceschini ◽  
Francesca Vecchi ◽  
Francesco Tondolo ◽  
Beatrice Belletti ◽  
Javier Sánchez Montero ◽  
...  
Keyword(s):  
Pit Depth

The Corrosion Evaluation Methodology of the Lock Gate

2014 ◽  
Vol 937 ◽  
pp. 105-108
Author(s):  
Chao Hua Jiang ◽  
Ke Fan ◽  
Xiang Yun Luo ◽  
Liang Qian
Keyword(s):  
Coating Thickness ◽  
Evaluation Methodology ◽  
Corrosion Depth ◽  
Corrosion Detection ◽  
Surrounding Environment ◽  
Corrosion Evaluation ◽  
Rating Method ◽  
Pit Depth ◽  
Environment Performance ◽  
Lock Gate

Influenced by surrounding environment, performance load and eroded by all kinds of media, the structure of lock gate prone to corrosion phenomena. Therefore, aimed at the situation of gate corrosion, to carry out the appraisal method for gate, a gate corrosion detection rating method is established. Based on the environment characteristics, taking corrosion appearance, coating thickness, the residue corrosion depth and corrosion pit depth as the index to evaluate,provides the judgment and evaluation basis for the lock gate is in need of repair.

scholarly journals Pitting Corrosion of Natural Aged Al–Mg–Si Extrusion Profile

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1081 ◽  
Author(s):  
Quanmei Guan ◽  
Jing Sun ◽  
William Wang ◽  
Junfeng Gao ◽  
Chengxiong Zou ◽  
...  
Keyword(s):  
Pitting Corrosion ◽  
High Speed ◽  
Three Dimensional ◽  
Optical Microscope ◽  
Damage Initiation ◽  
Coarse Grains ◽  
Corrosion Risk ◽  
Heterogeneous Microstructures ◽  
Set Up ◽  
Pit Depth

With the quick development of the high-speed railway and the service of the China Railway High-speed (CRH) series for almost a decade, one of the greatest challenges is the management/maintenance of these trains in environmental conditions. It is critical to estimate pitting damage initiation and accumulation and set up a corresponding database in order to support the foundations for interactive corrosion risk management. In this work, the pitting corrosion of a nature-aged commercial 6005A-T6 aluminum extrusion profile for 200 days was studied comprehensively. The heterogeneous microstructures were conventionally identified by the in situ eddy current, suggesting which investigated regions to fabricate samples for. After constant immersion for 240 h in 3.5 wt % NaCl, the shapes and depths of the pits were captured and measured by optical microscope (OM) and three-dimensional optical profilometry (OP), providing detailed quantification of uniform pitting corrosion. The typical features of the pits dominated by the distribution of precipitates include the peripheral dissolution of the Al matrix, channeling corrosion, intergranular attack, and large pits in the grains. Due to the high density of continuous anodic and cathodic particles constituted by alloying elements in coarse grains, the number of pits in the coarse grains was the highest while the number in the fine grains was the lowest, indicating that fine grains have the best corrosion resistance. The experimental dataset of the pit depth integrated with its corresponding microstructure would set the benchmark for further modeling of the pit depth and the remaining ductility, in order to manage the damage tolerance of the materials.

scholarly journals Electrochemical evaluation of the hydroxyapatite coating synthesized on the AZ91 by electrophoretic deposition route

2021 ◽  
Vol 1 (2) ◽  
pp. 85-91
Author(s):  
Arezoo Jangjoo Tazeh Kand ◽  
Fereshteh Afaghi ◽  
Arvin Taghizadeh Tabrizi ◽  
Hossein Aghajani ◽  
Hilal Demir Kivrak
Keyword(s):  
Corrosion Resistance ◽  
Electrophoretic Deposition ◽  
Electrochemical Impedance ◽  
Peak Height ◽  
Surface Parameters ◽  
Force Microscopy ◽  
Maximum Peak ◽  
Meaningful Relationship ◽  
Sbf Solution ◽  
Pit Depth

The hydroxyapatite layer was deposited on the commercial magnesium alloy of AZ91 by electrophoretic deposition route, and the corrosion behavior of applied layers was studied by polarization and electrochemical impedance spectroscopy at the Simulated Body Fluid (SBF) solution. The best corrosion resistance improvement was obtained for the sample synthesized at 40 V within 4 minutes. Also, the morphology of coated samples was studied by atomic force microscopy (AFM) and the surface parameters were measured. It could be concluded that the calculated values for surface parameters including surface roughness, maximum peak height, maximum pit depth, and maximum peak have a meaningful relationship with corrosion resistance.

scholarly journals Corrosion Characterization at Surface and Subsurface of Iron-Based Buried Water Pipelines

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5877
Author(s):  
Dessalegn Ahmed Yeshanew ◽  
Moera Gutu Jiru ◽  
Gulam Mohammed Sayeed Ahmed ◽  
Irfan Anjum Badruddin ◽  
Manzoore Elahi M. Soudagar ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Addis Ababa ◽  
Optical Microscope ◽  
Galvanized Steel ◽  
Uniform Corrosion ◽  
Corrosion Morphology ◽  
Pipe Surface ◽  
Pit Depth ◽  
Area And Volume

Water pipe surface deterioration is the result of continuous electrochemical reactions attacking the surface due to the interaction of the pipe surface with environments through the time function. The study presents corrosion characterization at the surface and sub-surface of damaged ductile iron pipe (DIP) and galvanized steel (GS) pipes which served for more than 40 and 20 years, respectively. The samples were obtained from Addis Ababa city water distribution system for the analysis of corrosion morphology patterns at different surface layers. Mountains 8.2 surface analysis software was utilized based on the ISO 25178-2 watershed segmentation method to investigate corrosion features of damaged pipe surface and to evaluate maximum pit depth, area, and volume in-situ condition. Based on the analysis maximum values of pit depth, area and volume were 380 μ m, 4000 μm2, and 200,000 μm3, respectively, after 25% loss of the original 8 mm thickness of DIP. Similarly, the pit depth of the GS pipe was 390 μm whereas the maximum pit area and volume are 4000 μm2 and 16,000 μm3, respectively. In addition, characterizations of new pipes were evaluated to study microstructures by using an optical microscope (OM), and a scanning electron microscope (SEM) was used to analyze corrosion morphologies. Based on the SEM analysis, cracks were observed at the sub-surface layer of the pipes. The results show that uniform corrosion attacked the external pipe surface whereas pitting corrosion damaged the subsurface of pipes. The output of this study will be utilized by water suppliers and industries to investigate corrosion phenomena at any damage stage.

Research on the bionic design of the middle trough of a scraper conveyor based on the finite element method

2018 ◽  
Vol 233 (9) ◽  
pp. 3286-3301 ◽  
Author(s):  
Bo Li ◽  
Xuewen Wang ◽  
Rui Xia ◽  
Zhaojian Yang ◽  
Yu Liu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Contact Analysis ◽  
Strengthening Effect ◽  
Fatigue Wear ◽  
Important Indicator ◽  
Optimal Value ◽  
Scraper Conveyor ◽  
Thermal Wear ◽  
Orthogonal Test Design ◽  
Pit Depth

Working life of the middle trough is an important indicator of the scraper conveyor. Improving the wear resistance of the middle trough can effectively prolong the service life. Based on the nonsmooth wear-resistant theory, the bionic optimization of the middle trough was carried out by designing the pits on the surface of the middle plate. The orthogonal test design of L9 (34) four factors and three levels was used. The structural static analysis and frictional contact analysis of the original middle trough sample and nine groups of the bionic middle trough samples were carried out respectively, and the simulation results were compared. Results showed that the pits had stress slow-release effect, torque effect, edge strengthening effect, and the function of collecting wear debris. So the pits could reduce fatigue wear, abrasive wear, impact wear, adhesive wear, thermal fatigue, and thermal wear on the middle trough. Then, the influence of pits' parameters on the wear resistance of the nonsmooth surface was studied by the contact analysis of the rectangular blocks. Results showed that the surface of the pit was easily deformed to produce more compressive and bending strain energy. The pits had the effect of releasing stress thus improving the wear resistance of the nonsmooth surface. At the same time, with the increase of the length and spacing of the pits, the wear resistance of the nonsmooth surface increased first and then decreased. There was an optimal value as the length of the pit was 2 mm and spacing was 9 mm. With the increase of the pit depth, the wear resistance of the nonsmooth surface increased gradually.

Plasticity in extended phenotypes: how the antlion Myrmeleon crudelis adjusts the pit traps depending on biotic and abiotic conditions

2019 ◽  
Vol 66 (1-2) ◽  
pp. 41-47 ◽  
Author(s):  
Alejandro G. Farji-Brener ◽  
Sabrina Amador-Vargas
Keyword(s):  
Abiotic Factors ◽  
Plant Cover ◽  
Coarse Grained ◽  
Abiotic Conditions ◽  
Fine Grained ◽  
Fine Soil ◽  
Fine Grained Soil ◽  
Trap Size ◽  
Pit Depth ◽  
Pit Design

Abstract The physical structures built by animals are considered extended phenotypes that reflect how organisms make decisions and deal with changes in their biotic and abiotic environment. We summarize the results of several studies on Myrmeleon crudelis, a neuropteran larva that digs pit-traps in the soil to capture small arthropods (mostly ants) in the tropical dry forests of Costa Rica. Specifically, we showed how this species responds to varying biotic and abiotic conditions with changes in the design and/or location of its pit traps. Several experiments and field comparisons indicate that: 1) antlions adjust the pit design according to the abundance and type of prey. When prey is scarce, antlions increased trap diameter, an architectural adjustment that enhances the probability of prey encounter. Antlions that experienced high prey abundance, but the prey easily escaped, then increased pit depth, an adjustment that increases the chance of prey retention; 2) soil compaction strongly reduced pit-trap size and abundance; 3) antlions preferred soils with high proportion of fine-particle size to build pits. In fine-grained soil, pit-traps are larger and more efficient to capture prey than traps in coarse-grained soils; and 4) pit-traps may also be affected through indirect effects of soil structure and vegetation cover. Areas with fine-soil presented less plant cover, and plant cover could be beneficial for antlions because it acts as a shelter against direct sunlight and rainfall, or it may represent a cost because it is a source of leaflitter falling in the pits. The works summarized here how trap-building predators can exhibit considerable flexibility in trap construction in response to various biotic and abiotic factors, emphasizing how the study of extended phenotypes can be a useful approach to better understand the flexibility of foraging behaviors.

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