scholarly journals Influence of Arc Power on Keyhole-Induced Porosity in Laser + GMAW Hybrid Welding of Aluminum Alloy: Numerical and Experimental Studies

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1328 ◽  
Author(s):  
Guoxiang Xu ◽  
Pengfei Li ◽  
Lin Li ◽  
Qingxian Hu ◽  
Jie Zhu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fluid Flow ◽  
Solidification Rate ◽  
Gas Metal Arc Welding ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Gas Bubble ◽  
Hybrid Welding ◽  
Destructive Testing ◽  
Arc Power

A three-dimensional numerical model is used to simulate heat transfer and fluid flow phenomena in fiber laser + gas metal arc welding (GMAW) hybrid welding of an aluminum alloy, which incorporates three-phase coupling and is able to depict the keyhole dynamic behavior and formation process of the keyhole-induced porosity. The temperature profiles and fluid flow fields for different arc powers are calculated and the percent porosities of weld beads were also examined under different conditions by X-ray non-destructive testing (NDT). The results showed that the computed results were in agreement with the experimental data. For hybrid welding, with raising arc power, the keyhole-induced porosity was reduced. Besides the solidification rate of the molten pool, the melt flow was also closely related to weld porosity. A relatively steady anti-clockwise vortex caused by arc forces tended to force the bubble to float upwards at the high temperature region close to the welding heat source, which benefits the escape of the gas bubble from the melt pool. When increasing the arc power, the anti-clockwise region was strengthened and the risk of the gas bubble for capture by the liquid/solid interface underneath the keyhole tip was diminished, which resulted in the lower weld percent porosity.

Numerical Analysis on the Temperature Field in Laser-Plasma Hybrid Welding of an Aluminum Alloy

2008 ◽  
Vol 580-582 ◽  
pp. 279-282
Author(s):  
Zhi Ning Li ◽  
Bao Hua Chang ◽  
Dong Du ◽  
Hua Zhang
Keyword(s):  
Heat Transfer ◽  
Aluminum Alloy ◽  
Laser Plasma ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transfer Model ◽  
Heat Sources ◽  
Hybrid Welding ◽  
Plasma Arc ◽  
Simulation Results

A three dimensional heat transfer model on laser-plasma hybrid welding has been proposed, that takes into account the interaction between laser beam and plasma arc. Through FEM computation, the temperature fields were computed and analyzed for an Al-Li alloy during laserplasma hybrid welding with different distances between the two heat sources. The simulation results are in agreement with the experimental results.

A Study on the Three-Dimensional Analysis of Heat and Fluid Flow in Gas Metal Arc Welding Using Boundary-Fitted Coordinates

1994 ◽  
Vol 116 (1) ◽  
pp. 78-85 ◽  
Author(s):  
J.-W. Kim ◽  
S.-J. Na
Keyword(s):  
Surface Tension ◽  
Fluid Flow ◽  
Weld Pool ◽  
Surface Deformation ◽  
Driving Forces ◽  
Gma Welding ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Weld Bead ◽  
Surface Boundary

Computer simulation of three-dimensional heat transfer and fluid flow in gas metal arc (GMA) welding has been studied by considering the three driving forces for weld pool convection, that is the electromagnetic force, the buoyancy force, and the surface tension force at the weld pool surface. Molten surface deformation, particularly in the case of GMA welding, plays a significant part in the actual weld size and should be considered in order to accurately evaluate the weld pool convection. The size and profile of the weld pool are strongly influenced by the volume of molten electrode wire, impinging force of the arc plasma, and surface tension of molten metal. In the numerical simulation, difficulties associated with the irregular shape of the weld bead have been successfully overcome by adopting a boundary-filled coordinate system that eliminates the analytical complexity at the weld pool and bead surface boundary. The method used in this paper has the capacity to determine the weld bead and penetration profile by solving the surface equation and convection equations simultaneously.

DEPENDENCE OF THE RAIL MFL TESTING DATA ON THE SPEED ACCORDING TO THE RESULTS OF COMPUTER SIMULATION AND EXPERIMENT

2020 ◽  
pp. 24-33
Author(s):  
A. G. Antipov ◽  
A. A. Markov
Keyword(s):  
Computer Simulation ◽  
Magnetic Flux ◽  
Eddy Currents ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Point Of View ◽  
Magnetic Sensors ◽  
Destructive Testing ◽  
Wide Range ◽  
Flux Leakage

Research of magnetic flux leakage signals of rail non-destructive testing in a wide range of scanning speeds is carried out. The results of three-dimensional computer simulation show significant changes in the distribution of the magnetic field in the depth of the rail at high motion speeds of the magnetizer. The appearance of low magnetization zones in the places most distant from the surface of the rail due to the influence of eddy currents is predicted. It is concluded that to detect defects that lie deep under the surface of the rail, magnetic sensors should be shifted towards the rear pole. The simulation results are in correct agreement with the results of experimental studies carried out on railway tracks at testing speeds up to 60 km/h. The effect of the formation at high scanning speeds of a tail magnetic flux behind the rear pole of the magnetizer is considered. Registration of this flux leakage data is promising from the point of view of detecting deep-seated defects, as well as separating signals from surface and internal flaws at high inspection speeds.

Acoustic and Photoacoustic Inspection of Through-Silicon Vias in the GHz-Frequency Band

2017 ◽  
Author(s):  
Sebastian Brand ◽  
Michael Kögel ◽  
Frank Altmann ◽  
Ingrid DeWolf ◽  
Ahmad Khaled ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Frequency Band ◽  
Process Development ◽  
Three Dimensional ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Vertical Interconnection ◽  
Testing Techniques ◽  
Silicon Vias ◽  
Non Destructive

Abstract Through Silicon Via (TSV) is the most promising technology for vertical interconnection in novel three-dimensional chip architectures. Reliability and quality assessment necessary for process development and manufacturing require appropriate non-destructive testing techniques to detect cracks and delamination defects with sufficient penetration and imaging capabilities. The current paper presents the application of two acoustically based methods operating in the GHz-frequency band for the assessment of the integrity of TSV structures.

scholarly journals Effect of Laser Power on Microstructure and Micro-Galvanic Corrosion Behavior of a 6061-T6 Aluminum Alloy Welding Joints

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Huiling Zhou ◽  
Fanglian Fu ◽  
Zhixin Dai ◽  
Yanxin Qiao ◽  
Jian Chen ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Laser Power ◽  
Galvanic Corrosion ◽  
Gas Metal Arc Welding ◽  
Immersion Test ◽  
Intermetallic Particles ◽  
Metal Arc Welding ◽  
Corrosion Behaviors ◽  
Welding Joints ◽  
Corrosion Pits

The 6061-T6 aluminum alloy welding joints were fabricated using gas metal arc welding (GMAW) of various laser powers, and the effect of laser power on the microstructure evolution of the welding joints was investigated. The corrosion behaviors of 6061-T6 aluminum alloy welding joints were investigated in 3.5 wt% NaCl solution using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the micro-galvanic corrosion initiation from Mg2Si or around the intermetallic particles (Al-Fe-Si) is observed after the immersion test due to the inhomogeneous nature of the microstructure. The preferential dissolution of the Mg2Si and Al-Fe-Si is believed to be the possible cause of pitting corrosion. When the laser power reached 5 kW, the microstructure of the welded joint mainly consisted of Al-Fe-Si rather than the Mg2Si at 2 kW. The relatively higher content of Al-Fe-Si with increasing in laser power would increase the volume of corrosion pits.

scholarly journals Characterization of Precipitation in 7055 Aluminum Alloy by Laser Ultrasonics

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 275
Author(s):  
Zhenge Zhu ◽  
Hao Peng ◽  
Yacheng Xu ◽  
Xueyong Song ◽  
Jinrong Zuo ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Laser Ultrasonics ◽  
Precipitate Size ◽  
Destructive Testing ◽  
Laser Ultrasonic ◽  
Precipitated Phase ◽  
Transmission Electron ◽  
7055 Aluminum Alloy ◽  
The Time Domain

After different rolling conditions, four 7055 aluminum alloy samples with different precipitation sizes were measured by scanning electron microscope, transmission electron microscope and laser ultrasonic. The attenuation coefficients of ultrasound measured by laser ultrasonic were calculated in the time domain, frequency domain and wavelet denoising, respectively. The relationship between the precipitate size and attenuation coefficient was established. The results show that the attenuation of the ultrasonic wave is related to the size of the precipitated phase; this provides a new method for rapid non-destructive testing of the precipitation of aluminum alloys.

scholarly journals Fast multipole solvers for three-dimensional radiation and fluid flow problems

1999 ◽  
Vol 7 ◽  
pp. 408-417 ◽  
Author(s):  
J. H. Strickland ◽  
L. A. Gritzo ◽  
R. S. Baty ◽  
G. F. Homicz ◽  
S. P. Burns
Keyword(s):  
Fluid Flow ◽  
Three Dimensional ◽  
Fast Multipole ◽  
Flow Problems
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