Effect of Gas Velocity and Particle Velocity on Coating Adhesion in Wire Arc Spraying

1996 ◽  
Author(s):  
X. Wang ◽  
J. Heberlein ◽  
E. Pfender ◽  
W. Gerberich
Keyword(s):  
Bond Strength ◽  
Particle Velocity ◽  
High Speed ◽  
Vision System ◽  
Arc Spraying ◽  
Gas Velocity ◽  
Coating Quality ◽  
Wire Arc Spraying ◽  
Particle Velocities ◽  
The Moment

Abstract In wire arc spraying, atomizing gas velocity and particle velocity are important factors influencing coating quality. A nozzle with secondary gas injection has been developed to increase the gas velocity and to improve coating quality. In this study, wire arc spraying of stainless steel on aluminum substrates has been investigated with the objective of establishing correlations between atomizing gas velocities, particle velocities, particle sizes and coating bond strength. Cold gas velocity is measured with a Pitot tube. Particle velocities are determined from high speed images of particle streaks taken with a Kodak high speed vision system and evaluated using image analysis. Bond strength is measured with pull-off tensile test. Secondary gas atomization clearly leads to improved adhesion due to additional metallurgical bonding between the coating and the substrate achieved through higher particle temperatures at the moment of impact.

Influence of Process Parameters and Geometry of the Spraying Nozzle on the Properties of Titanium Deposits Obtained in Wire Arc Spraying

2015 ◽  
Vol 1111 ◽  
pp. 211-216
Author(s):  
Bogdan Florin Toma ◽  
Iulian Ionita ◽  
Diana Antonia Gheorghiu ◽  
Lucian Eva ◽  
Costică Bejinariu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Process Parameters ◽  
High Speed ◽  
Electrical Current ◽  
Electric Arc ◽  
Arc Spraying ◽  
Oxide Content ◽  
Spray Parameters ◽  
Influence Of Process Parameters ◽  
Wire Arc Spraying

Influence of the process parameters and geometry of the spraying nozzle on the properties of titanium deposits obtained in wire arc spraying. Wire arc spraying is a process in which through minor modifications of the spray parameters, they can have a major impact on the coatings properties. In this paper there is presented a study on the influence of process parameters and fluid dynamics of the atomization gas on the properties of titanium deposits (14T - 99.9% Ti). For this there were used three different frontal spraying nozzles, having different geometries, and were varied the spraying gas pressure and the electrical current on three levels. There were evaluated the particles velocity, coating density, chemical composition and characteristic interface between deposition and substrate. Obviously, the high speed of the atomization gas determinate the improving of all properties, but in the same time increased the oxide content in the layer. However, the oxidation can be drastically reduced if the melting and atomization of the wire droplets is produced at the point of formation of the electric arc, and the spraying jet is designed to constrain the electric arc. The assessment of deposits adherence allowed the observation of process parameters that contribute to its improvement.

A Study on the Arc Spraying of 7Cr13 Cored Wire and Tribological Properties of the Composite Coating

1998 ◽  
Author(s):  
B. Xu ◽  
S. Ma ◽  
J. Wang ◽  
J. Tan
Keyword(s):  
Bond Strength ◽  
Composite Coating ◽  
Tribological Properties ◽  
High Hardness ◽  
Wear Resistant Coating ◽  
Arc Spraying ◽  
Metallurgical Process ◽  
Cored Wire ◽  
Wear Resistant ◽  
Wire Arc Spraying

Abstract For the purpose of getting high hardness and high wear-resistant coating by arc spraying technology, the arc spraying of 7Cr13 cored wire is adopted in this paper. The metallurgical process of the cored wire arc spraying is discussed. The bond strength, hardness and tribological properties of the composite coating are investigated.

Motion Generation for a Sword-Fighting Robot Based on Quick Detection of Opposite Player’s Initial Motions

2015 ◽  
Vol 27 (5) ◽  
pp. 543-551 ◽  
Author(s):  
Akio Namiki ◽  
◽  
Fumiyasu Takahashi
Keyword(s):  
Least Squares ◽  
High Speed ◽  
Least Squares Method ◽  
Vision System ◽  
Experimental Results ◽  
Change Points ◽  
Motion Generation ◽  
Robot System ◽  
The Moment ◽  
Human Player

<div class=""abs_img""> <img src=""[disp_template_path]/JRM/abst-image/00270005/11.jpg"" width=""300"" /> Defensive motion against attack</div> In this paper, we discuss how to generate defensive motions for a sword-fighting robot based on quick detection of the opposite player’s initial motions. Our sword-fighting robot system, which has a stereo high-speed vision system, recognizes both the position of a human player and that of the sword grasped by the robot’s hand. Further, it detects the moment when the human player initiates a move using ChangeFinder, which is a method of detecting change points. Next, using least squares method, it predicts the possible trajectories of the sword of the human player from the moment when the attack starts. Finally, it judges the type of the attack and generates an appropriate defensive motion. The effectiveness of the proposed algorithm is verified by experimental results. </span>

scholarly journals Analysis and Modeling of Particle Velocities in Premixed Abrasive Water Jets

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Weiqin Zuo ◽  
Cheng Huang ◽  
Yanwei Liu ◽  
Hongkai Han ◽  
Fuchang Hao ◽  
...  
Keyword(s):  
Particle Velocity ◽  
High Speed ◽  
Oil And Gas ◽  
Interpolation Method ◽  
Velocity Model ◽  
Experimental Results ◽  
Average Error ◽  
Distribution Law ◽  
Pressure Pipe ◽  
Particle Velocities

The premixed abrasive jet possesses a strong strike ability and is widely used in oil and gas exploitation, machining, rust removal, and other fields. The superstrong, forceful impact of the premixed abrasive jet is mainly provided by high-speed abrasive groups. Hence, the abrasive velocity is the basis of this research, by applying the distribution law of abrasive impact force. In this paper, the particle velocity of the premixed abrasive jet is analyzed theoretically, and the corresponding particle velocity model is established. The real-time contrast interpolation method is employed to solve the problem of the variable drag coefficient. Factors such as the nozzle structure, average abrasive diameter, abrasive density, and jet flow are utilized to determine the abrasive velocity of the nozzle outlet. The numerical solution for the abrasive velocity is obtained by dividing the high-pressure pipe and nozzle into several sections, along the axis. Finally, the calculated particle velocity is compared with the particle image velocity measurement (PIV), to verify the correctness of the established model. These results demonstrate that the model calculation is in effective agreement with the experimental results. The deviation between the theoretical value and the experimental mean is 0.18 m/s. The standard deviation of the experimental results is 3.81-4.22 m/s, while the average error is less than 4%.

Gas-Liquid-Solid Three-Phase Flows Through Pipes: Particle Velocity Measurement and Prediction

2008 ◽  
Author(s):  
O. O. Bello ◽  
K. M. Reinicke ◽  
C. Teodoriu ◽  
M.-Y. Liu
Keyword(s):  
Particle Velocity ◽  
Pipe Flow ◽  
Particle Transport ◽  
High Speed ◽  
Particle Deposition ◽  
Transport Processes ◽  
Erosion Risk ◽  
Three Phase ◽  
Flow Systems ◽  
Particle Velocities

Particle transport issues in three-phase gas-liquid-solid flow systems continue to challenge petroleum as well as mining, petrochemical, biochemical, pharmaceutical, food, nuclear, pulp and paper industries. The poor knowledge of particle transport processes associated with three-phase gas-liquid-solid pipe flow has greatly hampered the design and cost-effectiveness of these systems. This paper presents experimental and computational studies on three-phase gas-liquid-solid pipe flow systems in order to increase the understanding of particle transport and dispersion behaviour as well as the conditions for solid particle deposition and erosion risk initiation. The non-invasive high-speed charge coupled device (CCD) measuring technique is used in this work to study the particle velocities in three-phase gas-liquid-solid pipe flow systems. A calculation method to predict particle velocity in the three-phase gas-liquid-solid pipe flow systems is proposed. The model is based on the fundamentals of the particle mechanics in the three-phase gas-liquid-solid pipe flow systems. A good agreement between experiment and prediction is obtained.

Method for Monitoring the Destruction Process of Materials Using a High-Speed Camera and a Catodioptric Stereo-Vision System

2014 ◽  
Vol 224 ◽  
pp. 145-150
Author(s):  
Piotr Garbacz ◽  
Piotr Czajka ◽  
Bartłomiej Burski
Keyword(s):  
Stereo Vision ◽  
High Speed ◽  
Mechanical Load ◽  
Vision System ◽  
Testing Machine ◽  
High Speed Camera ◽  
Destruction Process ◽  
Stereo Vision System ◽  
The Moment ◽  
Observation Path

The article presents a method for monitoring the destruction process of materials under mechanical load on a universal testing machine. Observations of the subjects are made using a high-speed camera and a catadioptric stereo-vision system. The camera allows for data acquisition with the capture speed more than a million frames per second (FPS) with reduced resolution. Catadioptric vision systems use mirrors and lenses in order to modify the observation path. In the proposed system four mirrors are required to divide the observation path into two separate paths. This enables monitoring the test specimens from different perspectives, which provides a number of advantages including information redundancy or stereovision. In order to verify the proposed method several metal specimens were put under mechanical load and monitored with the vision system. Test results are enclosed in the article. Selected registered images presenting the moment of the destruction are described in greater detail with data about the capture speed provided. The tests were conducted under front and back lighting in order to assess the best method of illumination.

scholarly journals High Velocity Pulsed Wire-Arc Spray

2000 ◽  
Author(s):  
R.W. Kincaid ◽  
F.D. Witherspoon
Keyword(s):  
High Velocity ◽  
Vision System ◽  
Arc Spraying ◽  
Pulsed Plasma ◽  
Wire Arc Spray ◽  
New Device ◽  
Arc Spray ◽  
High Particle ◽  
Molten Droplets ◽  
Wire Arc Spraying

Abstract Wire arc spraying has traditionally filled metallic coating needs for low end users, while higher quality coatings required the use of higher cost systems. A new high velocity wire arc spray device has been developed through a NASA SBIR project whose high particle velocity capabilities could provide high quality coatings while keeping costs well below those associated with HVOF and plasma spray approaches. In addition, this technique achieves these high velocities in an extremely short acceleration path. This new device employs a pulsed plasma as the accelerative medium for the molten droplets. This pulsed plasma is capable of accelerating the droplets from the tips of the wires up to high velocities and atomizing them to very fine size. This results in a fine microstructure in the deposit. Recent experiments using a Control-Vision system measured velocities for aluminum droplets in the range of 950-1500 m/s and stainless steel droplets in the range of 850 m/s and 925 m/s. These velocities are achieved with an acceleration distance of only 3.2 cm, thus making this process an ideal candidate for coating the interior of automotive cylinder bores and other areas where only a short acceleration region is available.

Particle Velocity in a Dense Gas-Solid Fluidized Bed

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Qicheng Wang ◽  
Kai Zhang ◽  
Kuanli Yang ◽  
Jianchun Jiang
Keyword(s):  
Fluidized Bed ◽  
Particle Velocity ◽  
Particle Diameter ◽  
Solid Material ◽  
Dense Gas ◽  
Gas Velocity ◽  
Strong Function ◽  
Optical Fiber Probe ◽  
Inner Diameter ◽  
Particle Velocities

The upflowing and downflowing particle velocities are investigated by using a two-optical fiber probe system in the dense gas-solid fluidized bed with an inner diameter of 0.185 m and a height of 3.000 m. Two kinds of glass ballotinis, belonging to Geldart type B classification, are selected as solid material. Experiments are conducted under different operating gas velocities, static bed heights, and particle diameters. The results indicate that the upflowing particle velocity is a strong function of operating gas velocity and particle diameter, while the downflowing particle velocity depends mainly on the operating gas velocity. When the ratio of the operating gas velocity to the minimum fluidization velocity of the particles keeps the same constant, the effect of the particle diameter on the upflowing and downflowing particle velocities can be ignored. Both direction and size of the solid particle velocity are related to the bubble behaviors in the fluidized bed, and the upflowing particle velocity is lower than the bubble rise velocity. Furthermore, the across-sectional, non-uniform flow structure in the bed increases slightly with increasing static bed height at the high operating gas velocity.

Penetration Dynamics of Solid Particles into Liquids High-Speed Experimental Results and Modelling

2005 ◽  
Vol 473-474 ◽  
pp. 429-434 ◽  
Author(s):  
Olga Verezub ◽  
György Kaptay ◽  
Tomiharu Matsushita ◽  
Kusuhiro Mukai
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Particle Velocity ◽  
Weber Number ◽  
High Speed ◽  
Solid Particles ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Critical Weber Number

Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

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