The Influence of the Powder Stream on High-Deposition-Rate Laser Metal Deposition with Inconel 718

Chen, Zhong; Pirch, Norbert; Gasser, Andrés; Poprawe, Reinhart; Schleifenbaum, Johannes Henrich

doi:10.3390/met7100443

Cited by 53 publications

(30 citation statements)

References 32 publications

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“…The authors propose that, from this threshold onwards, the increase in carrier gas flow accounts for additional turbulence of the particle stream for which the melt pool and dilution depth are decreased again. Similar findings were presented by Zhong et al [29] who proposed that particle velocity was the dominant factor for melt pool penetration depth when using a three-jet nozzle. Moreover, Shah et al [30] reported an increase of melt pool depth for increasing carrier gas flows.…”

Section: Variation Of Carrier and Shielding Gas Flowsupporting

confidence: 89%

“…Apparently, the use of larger shielding gas flow rates facilitates a shallower melt pool. In correlation with the previously seized suggestions of Zhong et al [29], it can be concluded that an increase in shielding gas flow leads to increased interaction and, thus, turbulence with the carrier gas flow, for which the powder particles cannot penetrate the melt pool as deeply as before.…”

Section: Variation Of Carrier and Shielding Gas Flowsupporting

confidence: 76%

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High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

2021

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Laser-based Directed Energy Deposition (DED-LB) represents a production method of growing importance for cladding and additive manufacturing through the use of metal powders. Yet, most studies utilize substrate materials with thicknesses of multiple millimeters, for which laser cladding of thin-sheet substrates with thicknesses less than 1 mm have only been scarcely studied in the literature. Most studies cover the use of pulsed laser sources, since sheet distortion due to excess energy input is a key problem in laser cladding of thin-sheet substrates. Hence, the authors of the present investigation seek to expand the boundaries of cladding thin-sheet substrates through the use of a high-speed laser cladding approach which utilizes a continuous-wave, ytterbium fiber laser and traverse speeds of 90 mms−1 to clad stainless steel sheets with a thickness of 0.8mm. Furthermore, fundamental process–property relationships for the target values of clad width, clad height, and dilution depth are studied and thoroughly discussed. Additionally, process maps for the target values are established based on manifold experiments, and the significance of process parameters on target values is studied using analysis of variance. The results demonstrate that clad widths as high as 1413 μm and dilution depths as low as 144 μm can be obtained by high-speed laser cladding of thin-sheet substrates. Thus, pathways toward thin-sheet substrates with enhanced performance are opened.

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Section: Variation Of Carrier and Shielding Gas Flowsupporting

confidence: 89%

Section: Variation Of Carrier and Shielding Gas Flowsupporting

confidence: 76%

High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

2021

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“…The typical patterns of powder density and particle temperature distributions were found to be dependent on the coaxial nozzle type by Kovalev et al [20]. Considering all these works, it can clearly be established that the nozzle design and gas parameters have a strong impact on the powder flow density, speed and trajectory, and hence directly influence the powder stream characteristics and the clad efficiency [21].…”

Section: Experimental Conditionsmentioning

confidence: 96%

Experimental and Numerical Analysis of Gas/Powder Flow for Different LMD Nozzles

Ferreira

Dal

Colin

et al. 2020

Metals

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The Laser Metal Deposition (LMD) process is an additive manufacturing method, which generates 3D structures through the interaction of a laser beam and a gas/powder stream. The stream diameter, surface density and focal plan position affect the size, efficiency and regularity of the deposit tracks. Therefore, a precise knowledge of the gas/powder streams characteristics is essential to control the process and improve its reliability and reproducibly for industrial applications. This paper proposes multiple experimental techniques, such as gas pressure measurement, optical and weighting methods, to analyze the gas and particle velocity, the powder stream diameter, its focal plan position and density. This was carried out for three nozzle designs and multiple gas and powder flow rates conditions. The results reveal that (1) the particle stream follows a Gaussian distribution while the gas velocity field is closer to a top hat one; (2) axial, carrier and shaping gas flow significantly impact the powder stream’s focal plan position; (3) only shaping gas, powder flow rates and nozzle design impact the powder stream diameter. 2D axisymmetric models of the gas and powder streams with RANS turbulent model are then performed on each of the three nozzles and highlight good agreements with experimental results but an over-estimation of the gas velocity by pressure measurements.

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“…With the relative movement of the laser scanning head and work table, the melt-pool solidifies, resulting in a layer deposition. Layer-by-layer depositions result in a 3D structure [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Three-Jet Powder Flow and Laser–Powder Interaction in Laser Melting Deposition: Modelling Versus Experimental Correlations

Mahmood

Popescu

Oane

et al. 2020

Metals

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Powder flow and temperature distribution are recognized as essential factors in the laser melting deposition (LMD) process, which affect not only the layer formation but also its characteristics. In this study, two mathematical models were developed. Initially, the three-jet powder flow in the Gaussian shape was simulated for the LMD process. Next, the Gaussian powder flow was coaxially added along with the moving laser beam to investigate the effect of powder flow on temperature distribution at the substrate. The powder particles’ inflight and within melt-pool heating times were controlled to avoid vapors or plasma formation due to excessive heat. Computations were carried out via MATLAB software. A high-speed imaging camera was used to monitor the powder stream distribution, experimentally, while temperature distribution results were compared with finite element simulations and experimental analyses. A close correlation was observed among analytical computation, numerical simulations, and experimental results. An investigation was conducted to investigate the effect of the focal point position on powder stream distribution. It was found that the focal point position plays a key role in determining the shape of the powder stream, such that an increment in the distance from the focus point will gradually transform the powder stream from the Gaussian to Transition, and from the Transition to Annular streams. By raising the powder flow rate, the attenuation ratio prevails in the LMD process, hence, decreasing the laser energy density arriving at the substrate. The computations indicate that, if the particle’s heating temperature surpasses the boiling point, a strong possibility exists for vapors and plasma formation. Consequently, an excessive amount of laser energy is absorbed by the produced vapors and plasma, thus impeding the deposition process.

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The Influence of the Powder Stream on High-Deposition-Rate Laser Metal Deposition with Inconel 718

Cited by 53 publications

References 32 publications

High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

Experimental and Numerical Analysis of Gas/Powder Flow for Different LMD Nozzles

Three-Jet Powder Flow and Laser–Powder Interaction in Laser Melting Deposition: Modelling Versus Experimental Correlations

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