scholarly journals Process Optimization of Dual-Laser Beam Welding of Advanced Al-Li Alloys Through Hot Cracking Susceptibility Modeling

2016 ◽  
Vol 47 (7) ◽  
pp. 3533-3544 ◽  
Author(s):  
Yingtao Tian ◽  
Joseph D. Robson ◽  
Stefan Riekehr ◽  
Nikolai Kashaev ◽  
Li Wang ◽  
...  
Keyword(s):  
Laser Beam ◽  
Process Optimization ◽  
Laser Beam Welding ◽  
Hot Cracking ◽  
Susceptibility Modeling ◽  
Dual Laser

scholarly journals Comparison of Hot Cracking Susceptibility of TIG and Laser Beam Welded Alloy 718 by Varestraint Testing

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 985 ◽  
Author(s):  
Pedro Alvarez ◽  
Lexuri Vázquez ◽  
Noelia Ruiz ◽  
Pedro Rodríguez ◽  
Ana Magaña ◽  
...  
Keyword(s):  
Grain Size ◽  
Laser Beam ◽  
Laser Beam Welding ◽  
Hot Cracking ◽  
Welding Parameters ◽  
Minor Effect ◽  
Alloy 718 ◽  
Material Source ◽  
Cross Sectional ◽  
Varestraint Test

Reduced hot cracking susceptibility is essential to ensure the flawless manufacturing of nickel superalloys typically employed in welded aircraft engine structures. The hot cracking of precipitation strengthened alloy 718 mainly depends on chemical composition and microstructure resulting from the thermal story. Alloy 718 is usually welded in a solution annealed state. However, even with this thermal treatment, cracks can be induced during standard industrial manufacturing conditions, leading to costly and time-consuming reworking. In this work, the cracking susceptibility of wrought and investment casting alloy 718 is studied by the Varestraint test. The test is performed while applying different welding conditions, i.e., continuous tungsten inert gas (TIG), low frequency pulsed TIG, continuous laser beam welding (LBW) and pulsed LBW. Welding parameters are selected for each welding technology in order to meet the welding quality criteria requested for targeted aeronautical applications, that is, full penetration, minimum cross-sectional welding width and reduced overhang and underfill. Results show that the hot cracking susceptibility of LBW samples determined by the Varestraint test is enhanced due to extended center line hot cracking, resulting in a fish-bone like cracking pattern. On the contrary, the minor effect of material source (wrought or casting), grain size and pulsation is observed. In fact, casting samples with a 30 times coarser grain size have shown better performance than wrought material.

Development of a novel optical measurement technique to investigate the hot cracking susceptibility during laser beam welding

2018 ◽  
Vol 63 (2) ◽  
pp. 435-441 ◽  
Author(s):  
N. Bakir ◽  
V. Pavlov ◽  
S. Zavjalov ◽  
S. Volvenko ◽  
A. Gumenyuk ◽  
...  
Keyword(s):  
Laser Beam ◽  
Measurement Technique ◽  
Optical Measurement ◽  
Laser Beam Welding ◽  
Hot Cracking

Laser Beam Welding With Simultaneous Gaussian Laser Preheating

1993 ◽  
Vol 115 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Y.-N. Liu ◽  
E. Kannatey-Asibu
Keyword(s):  
Heat Source ◽  
Laser Beam ◽  
Cooling Rate ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Input Power ◽  
Relative Power ◽  
Gaussian Source ◽  
Distribution Parameters ◽  
Dual Laser

An analytical solution of the dual, laser beam welding process is presented. It is based on a Gaussian distributed leading heat source for preheating, followed by a line source for the actual welding process. The effect of beam distribution parameters as well as interbeam spacing and relative power intensities on the resulting temperature distribution and cooling rate are presented. For a preheating Gaussian source of power 1550 W, the depth of region above 500°C is 2.25 mm, and that above 250°C is 3.5 mm. The cooling rate at the weld centerline without preheating for a temperature of 650° C, input power 1800 W, and welding velocity 20 mm/s is found to be 1004°C/s. Under the same conditions, the cooling rate with a 1550 W preheating Gaussian distributed heat source (beam distribution parameter 1 mm, and interbeam spacing 10 mm) is reduced to 570°C/s.

Developments and Trends in Laser Welding of Sheet Metal

2005 ◽  
Vol 6-8 ◽  
pp. 59-70 ◽  
Author(s):  
Frank Vollertsen
Keyword(s):  
Laser Beam ◽  
Sheet Metal ◽  
Spot Welding ◽  
Laser Beam Welding ◽  
Hot Cracking ◽  
Thick Sheet ◽  
Laser Systems ◽  
Thick Sheet Metal ◽  
Metal Welding ◽  
Remarkable Progress

There is some remarkable progress in laser beam welding of sheet metal which is driven by the advent of improved laser systems and process technologies. Here, potentials for reducing distortion and avoiding hot cracking are highlighted, and examples of current developments are given in the field of thin and thick sheet metal welding including spot welding of difficult-to-weld materials and material combinations.

Effect of Dual-Laser Beam Welding on Microstructure Properties of Thin-Walled γ-TiAl Based Alloy Ti-45Al-5Nb-0.2C-0.2B (TNB)

2012 ◽  
pp. 887-894 ◽  
Author(s):  
Jie Liu ◽  
Volker Ventzke ◽  
Peter Staron ◽  
Heinz-Guenter Brokmeier ◽  
Michael Oehring ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Beam Welding ◽  
Thin Walled ◽  
Dual Laser

scholarly journals The bulging effect and its relevance in high power laser beam welding

2021 ◽  
Vol 1135 (1) ◽  
pp. 012003
Author(s):  
Antoni Artinov ◽  
Xiangmeng Meng ◽  
Nasim Bakir ◽  
Ömer Üstündağ ◽  
Marcel Bachmann ◽  
...  
Keyword(s):  
Laser Beam ◽  
Penetration Depth ◽  
Weld Pool ◽  
High Power ◽  
High Speed ◽  
Laser Beam Welding ◽  
Hot Cracking ◽  
Alloying Elements ◽  
High Power Laser ◽  
Power Laser

Abstract The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and an infrared camera is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs more frequently during partial penetration above 6 mm and complete penetration above 8 mm penetration depth, respectively. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root.

LBW of Similar and Dissimilar Skin-Stringer Joints Part I: Process Optimization and Mechanical Characterization

2008 ◽  
Vol 38 ◽  
pp. 306-319 ◽  
Author(s):  
A. Prisco ◽  
F. Acerra ◽  
Antonio Squillace ◽  
G. Giorleo ◽  
C. Pirozzi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Structural Analysis ◽  
Aluminum Alloys ◽  
Laser Beam ◽  
Process Optimization ◽  
Mechanical Characterization ◽  
Laser Beam Welding ◽  
Filler Wire ◽  
Parent Materials

Laser beam welding of light alloys has always represented a big challenge for both designers and technologists due to the large number of process parameters to take into account and the variable responses of the different materials to be welded. In this paper the results of experimental research on laser beam welds of innovative heat treatable aluminum alloys is reported. The well known T geometry (a stringer welded to a skin) has been considered. Two different skins have been analyzed: AA 2139 and AA 6156, both in form of rolled sheets. Two different stringer have been analyzed: AA 2139 and PA 765, both in form of extruded parts. AA 4047 has been used as filler wire. In the first part of the paper, all the steps leading to the realization of sound welds will be described. The criteria used in order to assess the soundness of a weld was the absence of defects, such as cracks or large pores, verified by means of NDE. In the second part of study, both micro structural analysis and mechanical characterization of welds will be described and discussed. Conclusions will demonstrate the importance of the influence of chemical composition of the parts, above all stringer. The performance of the best welds, however, were very close to those of parent materials.

scholarly journals Laser Weldability of Different Al-Zn Alloys and its Improvement

2015 ◽  
Vol 828-829 ◽  
pp. 389-394 ◽  
Author(s):  
Josephin Enz ◽  
Stefan Riekehr ◽  
Volker Ventzke ◽  
Nikolai Kashaev
Keyword(s):  
Laser Beam ◽  
Laser Beam Welding ◽  
High Strength ◽  
Hot Cracking ◽  
Welding Parameters ◽  
The Novel ◽  
New Approach ◽  
Application Range ◽  
Novel Approach ◽  
Zn Alloys

Weld defects - such as porosity and hot cracking - occur especially during the laser beam welding of high-alloyed Al-Zn alloys. This significantly limits the application range of these promising high-strength alloys. In the present study the laser weldability of different Al-Zn alloys was investigated regarding the used welding parameters and the chemical composition of the alloys. In addition, the novel approach of the Helmholtz-Zentrum Geesthacht for overcoming the weldability problems was applied to the different Al-Zn alloys in order to assess its capability. It was shown that the laser weldability of Al-Zn alloys deteriorates with an increasing amount of Zn, Mg and Cu. The variation of laser beam welding parameters did not lead to any improvement of weldability. Only the use of the new approach resulted in promising welding results even for the high-alloyed Al-Zn alloys.

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