scholarly journals Microstructure Refinement on Crevice Corrosion of High-Speed Rail Steel U75V Visualized by an In Situ Monitoring System

2022 ◽  
Vol 8 ◽  
Author(s):  
Jian Wang ◽  
Binbin Zhang ◽  
Weichen Xu ◽  
Jie Zhang ◽  
Lihui Yang ◽  
...  
Keyword(s):  
Crevice Corrosion ◽  
High Speed ◽  
Rail Steel ◽  
In Situ Monitoring ◽  
Metal Loss ◽  
General Corrosion ◽  
High Speed Rail ◽  
Cooling Rates ◽  
Microstructure Refinement

Rail foot covered by a fastener will suffer from crevice corrosion, leading to thinning and localized attack of crevice interior posing a risk of failure. This work investigated crevice corrosion behavior of a typical pearlitic high-speed rail steel U75V, focusing for the first time on the effect of pearlitic microstructure refinement achieved by heat treatment with different cooling rates 2, 5, and 10°C/s. Under anodic polarization, localized dissolved spots presented on the as-received sample, where crevice corrosion mostly initiated from. For cooling rates 2 and 5°C/s, localized dissolved spots were also observed but crevice corrosion was mostly presented as general corrosion instead of from local spots, ascribed to enhanced tendency of uniform dissolution due to microstructure refinement and homogenization. For cooling rate 10°C/s, crevice corrosion expanded flocculently, ascribed to preferential dissolution of pearlitic nodules with entangled cementite due to over refinement. Crevice corrosion was obviously accelerated by microstructure refinement. Cooling rates 5 and 10°C/s led to the fastest and slowest expansion of the corroded area, respectively, while the corrosion depth was just the opposite based on the same amount of metal loss. This work provides important information regarding the effect of pearlitic microstructure refinement on crevice corrosion and introduces a facile method for in situ monitoring of crevice corrosion.

In situ monitoring of electrosprayed water microdroplets using laser and LED light attenuation technique: Comparison with ultra-high-speed camera imaging

2021 ◽  
Vol 129 (18) ◽  
pp. 183305
Author(s):  
Mário Janda ◽  
Mostafa E. Hassan ◽  
Viktor Martišovitš ◽  
Karol Hensel ◽  
Michal Kwiatkowski ◽  
...  
Keyword(s):  
High Speed ◽  
Light Attenuation ◽  
In Situ Monitoring ◽  
High Speed Camera ◽  
Led Light ◽  
Camera Imaging ◽  
Ultra High Speed ◽  
Technique Comparison

Uniaxial High-Speed Micro-Scale Three-Dimensional Surface Topographical Measurements Using Fringe Projection

2020 ◽  
Author(s):  
Yi Zheng ◽  
Beiwen Li
Keyword(s):  
High Speed ◽  
Sample Surface ◽  
3D Scanning ◽  
In Situ Monitoring ◽  
Fringe Projection ◽  
Depth Information ◽  
Projection Technique ◽  
Projection System ◽  
Loop Control

Abstract In-situ inspection has drawn many attentions in manufacturing due to the importance of quality assurance. Having an accurate and robust in-situ monitoring can assist corrective actions for a closed-loop control of a manufacturing process. The fringe projection technique, as a variation of the structured light technique, has demonstrated significant potential for real-time in-situ monitoring and inspection given its merits of conducting simultaneous high-speed and high accuracy measurements. However, high-speed 3D scanning methods like fringe projection technique are typically based on triangulation principle, meaning that the depth information is retrieved by analyzing the triangulation relationship between the light emitter (i.e., projector), the image receiver (i.e., camera) and the tested sample surface. Such measurement scheme cannot reconstruct 3D surfaces where large geometrical variations are present, such as a deep-hole or a stair geometry. This is because large geometrical variations will block the auxiliary light used in the triangulation based methods, which will resultantly cause a shadowed area to occur. In this paper, we propose a uniaxial fringe projection technique to address such limitation. We measured a stair model using both conventional triangulation-based fringe projection technique and the proposed method for comparison. Our experiment demonstrates that the proposed uniaxial fringe projection technique can perform high-speed 3D scanning without shadows appearing in the scene. Quantitative testing shows that an accuracy of 1.15% can be obtained using the proposed uniaxial fringe projection system.

scholarly journals In-situ characterization of laser-powder interaction and cooling rates through high-speed imaging of powder bed fusion additive manufacturing

2017 ◽  
Vol 135 ◽  
pp. 385-396 ◽  
Author(s):  
Umberto Scipioni Bertoli ◽  
Gabe Guss ◽  
Sheldon Wu ◽  
Manyalibo J. Matthews ◽  
Julie M. Schoenung
Keyword(s):  
Additive Manufacturing ◽  
High Speed ◽  
Powder Bed Fusion ◽  
In Situ Characterization ◽  
High Speed Imaging ◽  
Cooling Rates ◽  
Powder Bed

Investigation on wear and damage characteristics of high-speed rail steel with plasma selective quenching

Wear ◽  
2021 ◽  
Vol 486-487 ◽  
pp. 204100
Author(s):  
Jingmang Xu ◽  
Kai Wang ◽  
Xinyuan Liang ◽  
Qiang Guo ◽  
Ping Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Rail Steel ◽  
High Speed Rail ◽  
Damage Characteristics

Corrosion performance of a corrosion-resistant rail steel in the simulated subsea tunnel environment

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Qi Zhang ◽  
Min Zhu ◽  
Feng Cai ◽  
Man Liu ◽  
Xue Su ◽  
...  
Keyword(s):  
High Speed ◽  
Rail Steel ◽  
Salt Spray ◽  
Neutral Salt ◽  
Corrosion Performance ◽  
X Ray Diffraction ◽  
High Speed Rail ◽  
Corrosion Resistant ◽  
Electrochemical Tests ◽  
Subsea Tunnel

Abstract The corrosion performance of a newly developed corrosion-resistant rail steel (U68CuCr) was investigated and compared with that of a normally used high-speed rail steel (U71MnG) by neutral salt spray tests, electrochemical tests, X-ray diffraction analyses, and the scanning vibrating electrode technique. It was found that the weight loss and corrosion rate of U68CuCr were lower than those of U71MnG under the same corrosion conditions. In addition, due to the influence of alloying elements (copper and chromium) in U68CuCr, the rust layer was thicker and denser, resulting in a stronger protective effect. Moreover, U68CuCr had a higher corrosion potential in electrochemical tests. Finally, the dynamic corrosion process of U68CuCr in 2.2% NaCl solution mainly followed a lateral extension of corrosion. Therefore, the corrosion resistance of U68CuCr was better than that of U71MnG in the subsea tunnel environment.

scholarly journals Towards real-time in-situ monitoring of hot-spot defects in L-PBF: a new classification-based method for fast video-imaging data analysis

2021 ◽  
Author(s):  
Matteo Bugatti ◽  
Bianca Maria Colosimo
Keyword(s):  
Additive Manufacturing ◽  
Real Time ◽  
Process Monitoring ◽  
Defect Detection ◽  
High Speed ◽  
Data Extraction ◽  
In Situ Monitoring ◽  
Imaging Data ◽  
Computational Speed

AbstractThe increasing interest towards additive manufacturing (AM) is pushing the industry to provide new solutions to improve process stability. Monitoring is a key tool for this purpose but the typical AM fast process dynamics and the high data flow required to accurately describe the process are pushing the limits of standard statistical process monitoring (SPM) techniques. The adoption of novel smart data extraction and analysis methods are fundamental to monitor the process with the required accuracy while keeping the computational effort to a reasonable level for real-time application. In this work, a new framework for the detection of defects in metal additive manufacturing processes via in-situ high-speed cameras is presented: a new data extraction method is developed to efficiently extract only the relevant information from the regions of interest identified in the high-speed imaging data stream and to reduce the dimensionality of the anomaly detection task performed by three competitor machine learning classification methods. The defect detection performance and computational speed of this approach is carefully evaluated through computer simulations and experimental studies, and directly compared with the performance and computational speed of other existing methods applied on the same reference dataset. The results show that the proposed method is capable of quickly detecting the occurrence of defects while keeping the high computational speed that would be required to implement this new process monitoring approach for real-time defect detection.

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