| XU Yao-fei,LIU Si-si,YANG Zheng-hang,JIANG Sheng-qiang,LIU Jin-gang.Numerical Simulation of Particle Deposition Behavior of Ni-based Coatings by High-velocity Oxy-fuel Spraying[J],52(10):321-334, 359 |
| Numerical Simulation of Particle Deposition Behavior of Ni-based Coatings by High-velocity Oxy-fuel Spraying |
| Received:October 26, 2022 Revised:March 02, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.10.028 |
| KeyWord:high-velocity oxy-fuel spraying mechanical occlusion multi particles overlapping impact ABAQUS simulation. |
| Author | Institution |
| XU Yao-fei |
School of Mechanical Engineering and Mechanics, Xiangtan University, Hunan Xiangtan , China |
| LIU Si-si |
School of Mechanical Engineering and Mechanics, Xiangtan University, Hunan Xiangtan , China |
| YANG Zheng-hang |
School of Mechanical Engineering and Mechanics, Xiangtan University, Hunan Xiangtan , China |
| JIANG Sheng-qiang |
School of Mechanical Engineering and Mechanics, Xiangtan University, Hunan Xiangtan , China |
| LIU Jin-gang |
School of Mechanical Engineering and Mechanics, Xiangtan University, Hunan Xiangtan , China |
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| Abstract: |
| In order to explore the deposition characteristics of thermal spraying coating particles, it is necessary to consider the effect of subsequent random impact of particles with different particle sizes. In the research related to deposition characteristics of coating particles, many researchers mainly focus on the particles with the same particle size to impact together in neat rows. However in the actual spraying, the powder particles are interval powders, with particles with different particle sizes, and the impact on the substrate is also random. Therefore, few people consider this problem. In this work, a particle and substrate impact model was established in ABAQUS to study grid convergence based on dent depth and stress distribution of particle impact. At the same time, the reliability of the model was verified by experiments. Then, the deposition characteristics of the substrate impacted by particles at different incident angles, and the deposition characteristics when four particles continuously overlapped and impacted the substrate and multiple particles randomly impacted the substrate surface were analyzed with the validation model.The optimal grid number of the sediment model was 1 752 912, which not only reduced the calculation cost, but also obtained accurate results. The particle with a particle size of 20 µm had a large impact speed, but a large resilience, and poor adhesion to the substrate. The particle with a particle size of 40 µm had a moderate speed, but a large impact energy, so it had a good interface with the substrate. The incident angle of particles increased from 15° to 60°, and the particles were better attached to the substrate surface, when the particle velocity increased from 350 m/s to 500 m/s, sputtering may occur, which may cause adiabatic shear instability and form effective bonding. When four particles impacted the substrate, the deformation of the second particle and its effect on the substrate were the most obvious. When multiple particles with different particle sizes impacted the substrate at random, the shape of the filling particles was irregular due to the impact and deposition of subsequent particles, and the first layer of particles may form a mechanical bite with the substrate. Thermal spraying should be inclined at a certain angle and increased at a certain speed, which can expand the contact area between particles and substrate. At the same time, the deposition depth increases continuously to enhance the adhesion, so it is more conducive to the preparation of the coating. When the particles overlap and impact, the subsequent particles make the first particle increase the compression effect and embed more deeply into the stainless steel substrate, which is conducive to the subsequent bonding between particles and makes the coating more compact. When a number of particles with different particle sizes impact the substrate at random, due to the different initial velocities and temperatures obtained by the subsequent particles in the thermal spraying gun tube, the particles impact and deposit in the later stage, and there is no good flatness or deformation. At the same time, high plastic strain is observed between the first layer of deposited particles and the substrate, as well as between adjacent particles in the coating. This situation indicates that the coating is bonded, so it is necessary to increase the full combustion of oxygen and kerosene to fully soften particles with different particle sizes during the actual thermal spraying. At the same time, the best efforts should be made to obtain higher speed under the gun barrel air pressure. When impacting the substrate, it can be completely deformed, so as to obtain an ideal high-quality coating. |
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