Metal transfer modes for Wire Arc Additive Manufacturing Al-Mg alloys: Influence of heat input in microstructure and porosity

2021 ◽  
pp. 117271
Author(s):  
E. Aldalur ◽  
A. Suárez ◽  
F. Veiga
Keyword(s):  
Additive Manufacturing ◽  
Heat Input ◽  
Metal Transfer ◽  
Mg Alloys ◽  
Wire Arc Additive Manufacturing ◽  
Al Mg Alloys

Control of humping phenomenon and analyzing mechanical properties of Al–Si wire-arc additive manufacturing fabricated samples using cold metal transfer process

2021 ◽  
pp. 095440622199840
Author(s):  
Yashwant Koli ◽  
N Yuvaraj ◽  
Aravindan Sivanandam ◽  
Vipin
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Heat Input ◽  
Large Scale ◽  
High Deposition Rate ◽  
Bead Geometry ◽  
Layer By Layer ◽  
Cold Metal Transfer ◽  
Geometrical Shapes ◽  
Wire Arc Additive Manufacturing

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.

Influence of Metal Transfer Behavior Under Ar And CO2 Shielding Gases On Geometry And Surface Roughness of Single And Multilayer Structures In GMAW-Based Wire Arc Additive Manufacturing of Mild Steel

2021 ◽  
Author(s):  
Mitsugu Yamaguchi ◽  
Rikiya Komata ◽  
Tatsuaki Furumoto ◽  
Satoshi Abe ◽  
Akira Hosokawa
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Molten Pool ◽  
Multilayer Structure ◽  
Short Circuit ◽  
Metal Transfer ◽  
Geometric Accuracy ◽  
Transfer Behavior ◽  
Ar Gas ◽  
Wire Arc Additive Manufacturing

Abstract Wire arc additive manufacturing (WAAM) is advantageous for fabricating large-scale metallic components, however, a high geometric accuracy as that of other AM techniques cannot be achieved because of the deposition process with a large layer. This study focuses on the WAAM process based on gas metal arc welding (GMAW). To clarify the influence of shielding gas used to protect a molten metal during fabrication on the geometric accuracy of the built part obtained via the GMAW-based WAAM process, the influence of the metal transfer behavior on the geometry and surface roughness of the fabricated structures was investigated via visualization using a high-speed camera when single and multilayer depositions were performed under different heat inputs and gases. However, when using Ar gas, the heat flux from an arc to the workpiece is relatively low, limiting the depth of the molten pool during welding. The effect of its characteristics on the stair steps that are inevitably produced on the side face of the multilayer structure in the WAAM process was verified, and for a heat input of 1.17 kJ/cm under Ar gas, a higher geometric accuracy of the multilayer structure was obtained without interlayer cooling. The short circuit between the metal droplet and the fabricated surface, where the molten pool is insufficiently formed, resulted in a hump formation. Further, the metal transfer under Ar gas reduced the surface irregularities on the fabricated structure.

scholarly journals Thermo-mechanical simulation of overlaid layers made with wire + arc additive manufacturing and GMAW-cold metal transfer

2020 ◽  
Vol 64 (8) ◽  
pp. 1427-1435 ◽  
Author(s):  
C. Cambon ◽  
S. Rouquette ◽  
I. Bendaoud ◽  
C. Bordreuil ◽  
R. Wimpory ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Mechanical Simulation ◽  
Cold Metal ◽  
Wire Arc Additive Manufacturing

scholarly journals Effects of Material Properties on Angular Distortion in Wire Arc Additive Manufacturing: Experimental and Computational Analyses

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1399
Author(s):  
Sang-Cheol Park ◽  
Hee-Seon Bang ◽  
Woo-Jae Seong
Keyword(s):  
Additive Manufacturing ◽  
Material Properties ◽  
Heat Input ◽  
Coefficient Of Thermal Expansion ◽  
Angular Distortion ◽  
Substrate Thickness ◽  
Deformation Characteristics ◽  
Temperature Dependent ◽  
Temperature Dependent Properties ◽  
Wire Arc Additive Manufacturing

In wire arc additive manufacturing (AM), as in arc welding, arc heat thermally deforms substrates and articles. For industrial applications, deformation characteristics of various materials must be understood and appropriate materials and methods of reducing deformation must be devised. Therefore, angular distortions of different materials were investigated through bead-on-plate welding and finite element analysis. A model that simplifies temperature-dependent properties was developed to establish relationships between thermomechanical properties and angular distortion. A simplified model of temperature-dependent properties was used, and angular distortion characteristics were extensively investigated for different material properties and heat inputs. Coefficient of thermal expansion, density, and specific heat all notably affected angular distortion depending on heat input conditions. Results showed that during wire arc AM, flatness of both substrates and articles could vary depending on material properties, heat input, substrate thickness, and bead accumulation. Study findings can provide insight into deformation characteristics of new materials and how to mitigate thermal distortions.

scholarly journals Gas Metal Arc Welding Modes in Wire Arc Additive Manufacturing of Ti-6Al-4V

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2457
Author(s):  
Oleg Panchenko ◽  
Dmitry Kurushkin ◽  
Fedor Isupov ◽  
Anton Naumov ◽  
Ivan Kladov ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Process Data ◽  
Cold Metal Transfer ◽  
Wall Width ◽  
Metal Arc Welding ◽  
Wire Arc Additive Manufacturing

In wire arc additive manufacturing of Ti-alloy parts (Ti-WAAM) gas metal arc welding (GMAW) can be applied for complex parts printing. However, due to the specific properties of Ti, GMAW of Ti-alloys is complicated. In this work, three different types of metal transfer modes during Ti-WAAM were investigated: Cold Metal Transfer, controlled short circuiting metal transfer, and self-regulated metal transfer at a direct current with a negative electrode. Metal transfer modes were studied using captured waveform and high-speed video analysis. Using these modes, three walls were manufactured; the geometry preservation stability was estimated and compared using effective wall width calculation, the microstructure was analyzed using optical microscopy. Transfer process data showed that arc wandering depends not only on cathode spot instabilities, but also on anode processing properties. Microstructure analysis showed that each produced wall consists of phases and structures inherent for Ti-WAAM. α-basketweave in the center of and α-colony on the grain boundary of epitaxially grown β-grains were found with heat affected zone bands along the height of the walls, so that the microstructure did not depend on metal transfer dramatically. However, the geometry preservation stability was higher in the wall, produced with controlled short circuiting metal transfer.

scholarly journals Regional Control and Optimization of Heat Input during CMT by Wire Arc Additive Manufacturing: Modeling and Microstructure Effects

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1061
Author(s):  
Furong Chen ◽  
Yihang Yang ◽  
Hualong Feng
Keyword(s):  
Additive Manufacturing ◽  
Deposition Rate ◽  
Thermal History ◽  
Heat Input ◽  
Great Influence ◽  
Input Process ◽  
Cooling Process ◽  
Average Grain Size ◽  
Wire Arc Additive Manufacturing

Wire arc additive manufacturing (WAAM) of aluminum-magnesium (Al–Mg) ER5356 alloy deposits is accomplished by cold metal transfer (CMT). During the process, the temperature change of the alloy deposits has a great influence on molding quality, and the microstructure and properties of alloy deposits are also affected by the complex thermal history of the additive manufacturing process. Here, we used an inter-layer cooling process and controlled the heat input process to attempt to reduce the influence of thermal history on alloy deposits during the additive process. The results showed that inter-layer cooling can optimize the molding quality of alloy deposits, but with the disadvantages of a long test time and slow deposition rate. A simple and uniform reduction of heat input makes the molding quality worse, but controlling the heat input by regions can optimize the molding quality of the alloy deposits. The thermophysical properties of Al-Mg alloy deposits were measured, and we found that the specific heat capacity and thermal diffusivity of alloy deposits were not obviously affected by the temperature. The microstructure and morphology of the deposited specimens were observed and analyzed by microscope and electron back-scatter diffraction (EBSD). The process of controlled heat input results in a higher deposition rate, less side-wall roughness, minimum average grain size, and less coarse recrystallization. In addition, different thermal histories lead to different texture types in the inter-layer cooling process. Finally, a controlled heat input process yields the highest average microhardness of the deposited specimen, and the fluctuation range is small. We expect that the process of controlling heat input by model height region will be widely used in the WAAM field.

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