| ZHAO Sheng-ju,QI Wen-jun,HUANG Yan-hua,LEI Jing-feng.Numerical Simulation Study on Thermal Cycle Characteristics of Temperature Field of TC4 Surface Laser Cladding Ni60 Based Coating[J],49(2):301-308 |
| Numerical Simulation Study on Thermal Cycle Characteristics of Temperature Field of TC4 Surface Laser Cladding Ni60 Based Coating |
| Received:April 22, 2019 Revised:February 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.02.038 |
| KeyWord:laser cladding TC4 titanium alloy Ni60 thermal cycle microstructure numerical simulation |
| Author | Institution |
| ZHAO Sheng-ju |
School of Mechanical Engineering, Xinjiang University, Urumqi , China |
| QI Wen-jun |
School of Mechanical Engineering, Xinjiang University, Urumqi , China |
| HUANG Yan-hua |
School of Mechanical Engineering, Xinjiang University, Urumqi , China |
| LEI Jing-feng |
School of Mechanical Engineering, Xinjiang University, Urumqi , China |
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| Abstract: |
| The work aims to determine the optimal process parameters of laser cladding of TC4 titanium alloy, study its thermal cycle characteristics and analyze the influence of laser cladding temperature on microstructure. Based on the Sysweld software platform, the numerical simulation of TC4 titanium alloy laser cladding Ni60A-50%Cr3C2 powder was carried out with 3D Gaussian heat source. The temperature field cloud map and its thermal cycle characteristics were studied to simulate and calculate the maximum temperature, heating rate and cooling speed of laser cladding as well as the maximum depth of the molten pool and the width of the heat-affected zone, to verify by laser cladding experiments, and the scanning electron microscopy (SEM) images of the cladding layer were combined to study the effect of cooling rate on the microstructure of the cladding layer. It can be seen from the simulation that the spot diameter and the powder feeding speed in the laser cladding process parameters mainly affected the height and width of the cladding layer. The main influence factors of the temperature field distribution were the laser power and scanning speed. When the laser power was 500 W, and the scanning speed was 4 mm/s, the cladding layer was completely melted and well bonded to the substrate; when the maximum temperature of laser cladding was 2700 ℃, the maximum heating rate was about 2200 ℃/s, the maximum cooling rate was about 1200 ℃/s, the maximum depth of the molten pool was between 0.33 mm and 0.66 mm, and the width of the heat-affected zone was about 1.2mm; the cross-section morphology of the cladding layer obtained by the simulation and experiment was basically the same; the microstructure of the cladding layer obtained by different cooling rates was different, and the microstructure was composed of short cell crystals as the cooling rate decreased. And the dendrites gradually transformed into columnar crystals, cell crystals and planar crystals, and finally formed quenched acicular martensite. The optimum process parameters are laser power of 500 W and scanning speed of 4 mm/s. The cooling rate is an important factor affecting the microstructure of the cladding layer. The correctness of the simulation model and the feasibility of the method are verified by experiments. |
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