FEASIBILITY STUDY ON JOINING DISSIMILAR ALUMINUM ALLOYS AA6061 AND AA7075 BY TUNGSTEN INERT GAS (TIG)

2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Mahadzir Ishak ◽  
Nur Fakhriah Mohd Noordin ◽  
Luqman Hakim Ahmad Shah

The aim of this paper is to study the feasibility of welding dissimilar aluminum alloys AA6061 and AA7075 using different types of filler metals which are ER4043 and ER5356. The tungsten inert gas (TIG) welding method was used to butt joint these alloys. The effect of ER4043 (Si-rich) and ER5356 (Mg-rich) on weldability of the joint were studied through visual appearance, microstructures and hardness. It was found that, welding using filler ER5356 produced deeper penetration compared to filler ER4043. The depth of penetration obtained using filler ER5356 was 1.74 mm, while only 0.9 mm of penetration was obtained using ER4043. Microstructures at different zones of dissimilar TIG joints such as the fusion zone (FZ), the partially melted zone (PMZ) and the heat affected zone (HAZ) were identified. The grain size at FZ from filler ER5356 samples was finer compared to filler ER4043 which was 11.4 µm and 19.5 µm, respectively. The average hardness welding value of filler ER5356 samples was higher compared to filler ER4043 samples, which were 100HV and 86HV, respectively at HAZ of AA 6061, 110HV and 88HV, respectively at FZ, while 113HV and 85HV, respectively at HAZ of AA 7075. It can be concluded that TIG welding using the ER5356 filler yields better joint compared to ER4043.

Author(s):  
Morteza Ghaffarpour ◽  
Mohammad Kazemi ◽  
Mohammad Javad Mohammadi Sefat ◽  
Ahmad Aziz ◽  
Kamran Dehghani

In the present study, friction stir welding (FSW) and tungsten inert gas (TIG) techniques were used to join the dissimilar aluminum alloys of 5083-H12 and 6061-T6. The laboratory tests were designed using design of experiment (DOE) method. Variables for the FSW process were the rotational speed, traverse speed, shoulder diameter, and pin diameter. They changed in ranges of 700–2500 r/min, 25–400 mm/min, 10–14 mm, and 2–4 mm, respectively. In the case of TIG process, the variables were current intensity, traverse speed, and tilt angle. These parameters varied from 80 to 90 A, 200 to 400 mm/min, and 3° to 12°, respectively. The optimum amounts of parameters were obtained using response surface methodology (RSM). The RSM-based model was developed to predict ultimate tensile strength (UTS) of the welds produced. In FSW, the difference between predicted and measured UTS was about 1.28% and in TIG it was 1.78%. The good agreement between experimental and predicted results indicates the high accuracy of the developed model. Mechanical properties and also the microstructure of the welds were compared after optimizing both welding processes using RSM. The results showed that the welds produced by FSW indicated a considerably higher quality and also improved mechanical properties compared to TIG. Properties of the joints obtained by FSW in single-sided joints were more desirable. In the double-sided welds obtained by FSW these differences were of an even higher significance.


Author(s):  
Akash Deep ◽  
Vivek Singh ◽  
Som Ashutosh ◽  
M. Chandrasekaran ◽  
Dixit Patel

Abstract Austenitic stainless steel (ASS) is widely fabricated by tungsten inert gas (TIG) welding for aesthetic look and superior mechanical properties while compared to other arc welding process. Hitherto, the limitation of this process is low depth of penetration and less productivity. To overcome this problem activated tungsten inert gas (A-TIG) welding process is employed as an alternative. In this investigation the welding performance of conventional TIG welding is compared with A-TIG process using TiO2 and SiO2 flux with respect to weld bead geometry. The experimental investigation on A-TIG welding of ASS-201 grade shows TiO2 flux helps in achieve higher penetration as compared to SiO2 flux. While welding with SiO2 the hardness in HAZ and weld region higher than that of TIG welding process.


MRS Advances ◽  
2019 ◽  
Vol 4 (55-56) ◽  
pp. 3017-3029
Author(s):  
Juan Manuel Salgado L. ◽  
Abraham Silva Hernandez ◽  
Francisco Ignacio López Monroy ◽  
José Luis Ojeda Elizarráras ◽  
Jesús Mauricio Tello Rico

ABSTRACTEven though AA 7075 is an aluminum alloy with high mechanical properties, it is not often applied in manufacturing. This is so, because it is considered as very difficult to produce defect free welded joints. This is so, because this alloy has a tendency to hot cracking. The metallurgical problems that appear during welding of AA 7075 have not been fully solved but they have been reduced by applying alloys such as: 4043 and 5356 as filler metals. However, in literature there is little information about the metallurgical effects of these types of filler metals applied in arc welded joints of AA7075. This is especially true for Tungsten Inert gas welding. Therefore, this work is focused in comparing the microstructure and Vickers microhardness in weldments of AA 7075 with ER4043, ER5356 and AA7075 as filler metals. Besides, a set of welded joints with the three different filler metals were quenched after welding in order to modify the final microstructure. The results were evaluated by microstructural analysis focused on the Heat Affected Zone and Vickers microhardness and they were compared among them.


2020 ◽  
Vol 19 (04) ◽  
pp. 869-891
Author(s):  
Masoud Azadi Moghaddam ◽  
Farhad Kolahan

Flux-assisted tungsten inert gas welding process, also known as activated tungsten inert gas (A-TIG) welding, is extensively used in order to improve the performance of the conventional TIG welding process. In this study, the orthogonal array Taguchi (OA-Taguchi) method, regression modeling, analysis of variance (ANOVA) and simulated annealing (SA) algorithm have been used to model and optimize the process responses in A-TIG welding process. Welding current (I), welding speed (S) and welding gap (G) have been considered as process input variables for fabricating AISI316L austenitic stainless steel specimens. Depth of penetration (DOP) and weld bead width (WBW) have been taken into account as the process responses. In this study, SiO2, nano-particle has been considered as an activating flux. To gather required data for modeling, statistical analysis and optimization purposes, OA-Taguchi based on the design of experiments (DOE) has been employed. Then the process responses have been measured and their corresponding signal-to-noise (S/N) ratio values have been calculated. Different regression equations have been applied to model the responses. Based on the ANOVA results, the most fitted models have been selected as an authentic representative of the process responses. Furthermore, the welding current has been determined as the most important variable affecting DOP and WBW with 68% and 88% contributions, respectively. Next, the SA algorithm has been used to optimize the developed models in such a way that WBW is minimized and DOP is maximized. Finally, experimental performance evaluation tests have been carried out, based on which it can be concluded that the proposed procedure is quite efficient (with less than 4% error) in modeling and optimization of the A-TIG welding process.


2020 ◽  
Vol 36 (01) ◽  
pp. 78-86
Author(s):  
Shaji Krishna Prasad ◽  
Andy Mathiazhagan ◽  
Pallichakkalayil Sasidharan Krishnadas

The study compared the effects of manual activated tungsten inert gas (A-TIG) welding and automated A-TIG welding on AISI (American Iron and Steel Institute)- 304 at three different values of current using commercially available powders of Al2O3, SiO2, Fe2O3, MgCl2, and TiO2 separately as activated flux and distilled water as carrier solvent. The effect of fluxes on the depth of penetration of the weldments, width of weldment, microstructure of the weldment, and microhardness of the weldment was investigated. Reverse Marangoni convection and arc constriction are found to be more effective in A-TIG manual welding, as aspect ratio obtained by A-TIG manual welding is greater as than that of automatic A-TIG welding. Microstructure of both the manual and automatic A-TIG-welded specimen is similar with no noticeable differences and almost same amount of intermetallic phases and carbon precipitates. Microhardness tests revealed that for Al2O3 and TiO2 fluxes, manual A-TIG-welded specimen have lower values of microhardness at weldment, heat-affected zone, and base metal than automated A-TIG-welded specimen. The aim of the study is to implement the manual A-TIG process in shipbuilding industry to improve the productivity of welding as automated A-TIG welding in the industry has limitations.


DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 150-155
Author(s):  
Elizabeth Hoyos Pulgarín ◽  
María Zuluaga-Posada ◽  
Yesid Montoya

Friction Stir Welding (FSW) has the advantage of generating sound welds on materials that generally present low weldability by traditional fusion welding processes, such as 2xxx and 7xxx aluminum alloys. Force measurement in FSW provides significant information about the process, the machine requirements, the effect of selected parameters, and weld soundness. In this paper, an axial force measuring device was designed, built, and tested to be used in a CNC adapted system. All tests were performed using AA 7075-T6 and a butt joint configuration. The forces obtained by the device match, in profile, key values, and trends, the ones found in literature which allows to conclude that this is a functional and sufficient device for the application.


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