Cold Metal Transfer Welding of AA6061 to AA7075: Mechanical Properties and Corrosion

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Nilay Çömez ◽  
Hülya Durmuş

Cold metal transfer (CMT) welding provides many advantages for welding of dissimilar materials and thin sheets with its superior heat input control mechanism. In this study, AA6061 and AA7075 aluminum alloys were joined with CMT welding. The effect of welding parameters on hardness, tensile strength, and corrosion rate was investigated. The Tafel extrapolation method was carried out to determine the corrosion rates of AA6061 and AA7075 base metals and AA6061–AA7075 joints. Increasing heat input was found to be detrimental for both mechanical properties and corrosion resistance. The outcomes showed that CMT welding produces adequate joints of AA6061–AA7075 in terms of mechanical properties and corrosion resistance, favorably with welding parameters that provide low heat input.

2019 ◽  
Vol 272 ◽  
pp. 40-46 ◽  
Author(s):  
Jin Yang ◽  
Anming Hu ◽  
Yulong Li ◽  
Peilei Zhang ◽  
Dulal Chandra Saha ◽  
...  

2019 ◽  
Vol 969 ◽  
pp. 685-690 ◽  
Author(s):  
S. Venukumar ◽  
Muralimohan Cheepu ◽  
T. Vijaya Babu ◽  
D. Venkateswarlu

In recent years, the continuous growth in manufacturing industries such as light weight structures, demands in increasing of its performance and functionality enhance the use of different materials for producing hybrid structures and thus the requirements for joining of dissimilar joints. The physical and metallurgical properties of the materials are utilised to get combined properties to achieve the product performance. On the other hand the joining methods are continuously challenging for joining of dissimilar materials. The present study reviews and describes the effective welding method of cold metal transfer for joining of dissimilar materials and its state of the art research in various materials joining. Cold metal transfer joining mechanism, capabilities of joining of dissimilar metals and their performance are reviewed. The current and emerging techniques of cold metal transfer welding method are reviewed. Methods and other technological parameters selection are described and future challenges for improving research methods on joining of dissimilar metals using cold metal transfer. Keywords: Cold Metal Transfer, MIG welding, Dissimilar materials, Mechanical properties.


Author(s):  
HaiYang Lei ◽  
YongBing Li ◽  
Blair E. Carlson ◽  
ZhongQin Lin

In order to meet the upcoming regulations on greenhouse gas emissions, aluminum use in the automotive industry is increasing. However, this increase is now seen as part of a multimaterial strategy. Consequently, dissimilar material joints are a reality, which poses significant challenges to conventional fusion joining processes. To address this issue, cold metal transfer (CMT) spot welding process was developed in the current study to join aluminum alloy AA6061-T6 as the top sheet to hot dip galvanized (HDG) advanced high strength steel (AHSS) DP590 as the bottom sheet. Three different welding modes, i.e., direct welding (DW) mode, plug welding (PW) mode, and edge plug welding (EPW) mode were proposed and investigated. The DW mode, having no predrilled hole in the aluminum top sheet, required concentrated heat input to melt through the Al top sheet and resulted in a severe tearing fracture, shrinkage voids, and uneven intermetallic compounds (IMC) layer along the faying surface, leading to poor joint properties. Welding with the predrilled hole, PW mode, required significantly less heat input and led to greatly reduced, albeit uneven, IMC layer thickness. However, it was found that the EPW mode could homogenize the welding heat input into the hole and thus produce the most stable welding process and best joint quality. This led to joints having an excellent joint morphology characterized by the thinnest IMC layer and consequently, best mechanical performance among the three modes.


2018 ◽  
Vol 8 (9) ◽  
pp. 1659 ◽  
Author(s):  
Youqiong Qin ◽  
Xi He ◽  
Wenxiang Jiang

Bead-on-plate cold metal transfer (CMT) brazing and overlap CMT welding–brazing of 7075 aluminium alloy and galvanized steel at different preheating temperatures were studied. The results indicated that AlSi5 filler wire had good wettability to galvanized steel. The preheating treatment can promote the spreadability of liquid AlSi5. For the overlap CMT welding–brazed joint, the microstructure of the joint was divided into four zones, namely, the interfacial layer, weld metal zone, zinc-rich zone, and heat affected zone (HAZ). The load force of the joints without preheating and 100 °C preheating temperature was 8580 N and 9730 N, respectively. Both of the joints were fractured in the fusion line with a ductile fracture. Further increasing the preheating temperature to 200 °C would decrease the load force of the joint, which fractured in the interfacial layer with a brittle fracture.


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