Dissimilar robotic cold metal transfer (CMT) welding of an aluminum alloy to galvanized steel

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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A heat source model for cold metal transfer (CMT) welding

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-015-4809-4 ◽

2015 ◽

Vol 122 (2) ◽

pp. 741-746 ◽

Cited By ~ 16

Author(s):

Amin S. Azar

Keyword(s):

Heat Source ◽

Source Model ◽

Metal Transfer ◽

Heat Source Model ◽

Cold Metal Transfer ◽

Cmt Welding ◽

Cold Metal

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Microstructure and mechanical properties of cold metal transfer welded galvanized steel/magnesium alloy dissimilar joints

International Journal of Modern Physics B ◽

10.1142/s0217979220400603 ◽

2019 ◽

Vol 34 (01n03) ◽

pp. 2040060

Author(s):

Chao Zhang ◽

Mingfang Wu ◽

Yuxin Wang ◽

Juan Pu

Keyword(s):

Magnesium Alloy ◽

Heat Input ◽

Interface Layer ◽

Metal Transfer ◽

Galvanized Steel ◽

Cold Metal Transfer ◽

Welding Joint ◽

Welding Heat Input ◽

Weld Appearance ◽

Cold Metal

The joining of magnesium alloy to galvanized steel was realized by cold metal transfer method with AZ31 magnesium alloy welding wire. Weld appearance, microstructure and tensile properties of Mg–steel joints under various welding parameters were investigated with different welding heat inputs. The results showed that magnesium alloy-steel brazed joints had good weld appearance. When the welding heat input was 141 J/mm, Zn elements were enriched in the Zn-rich zone (ZRZ), and the interface layer was composed of a large portion of Mg–Zn phases and minor Mg–Al phases. With the increase of welding heat input, Zn elements in the ZRZ gradually decreased, Fe/Al phase appeared in the interface layer, and the strength of welding joint increased. When the welding heat input was 159 J/mm, the tensile strength of welding joint reached the maximum value of 198 MPa. However, when the welding input was increased to 181 J/mm, Zn element in the ZRZ was burnt and volatilized seriously, resulting in poor wetting and spreading properties of liquid phase at the interface zone of the steel.

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Comparative Study of Laser-Arc Hybrid Welding for AA6082-T6 Aluminum Alloy with Two Different Arc Modes

Metals ◽

10.3390/met10030407 ◽

2020 ◽

Vol 10 (3) ◽

pp. 407 ◽

Cited By ~ 1

Author(s):

Xiaohui Han ◽

Zhibin Yang ◽

Yin Ma ◽

Chunyuan Shi ◽

Zhibin Xin

Keyword(s):

Aluminum Alloy ◽

Heat Affected Zone ◽

Metal Transfer ◽

Inert Gas ◽

Hybrid Welding ◽

Cold Metal Transfer ◽

Melted Zone ◽

Cold Metal ◽

Fracture Features ◽

Softening Region

The effects of arc modes on laser-arc hybrid welding for AA6082-T6 aluminum alloy were comparatively studied. Two arc modes were employed: pulsed metal inert gas arc and cold metal transfer arc. The results indicated that joints without porosity, undercutting, or other defects were obtained with both laser-pulsed metal inert gas hybrid welding (LPMHW) and laser-cold metal transfer hybrid welding (LCHW). Spatter was reduced, and even disappeared, during the LCHW process. The sizes of equiaxed dendrites and the width of the partially melted zone in the LPMHW joint were larger than those in the LCHW joint. The microhardness in each zone of the LPMHW joint was lower than that of the LCHW joint. The softening region in the heat-affected zone of the LPMHW joint was wider than that of the LCHW joint. The tensile strength of the LCHW joint was higher than that of the LPMHW joint. For the two joints, the fractures all occurred in the softening region in the heat-affected zone, and the fracture morphologies showed ductile fracture features. The dimples in the fractograph of the LCHW joint were deeper than those of the LPMHW joint.

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

Journal of Engineering Materials and Technology ◽

10.1115/1.4042863 ◽

2019 ◽

Vol 141 (3) ◽

Author(s):

Nilay Çömez ◽

Hülya Durmuş

Keyword(s):

Mechanical Properties ◽

Corrosion Resistance ◽

Heat Input ◽

Dissimilar Materials ◽

Metal Transfer ◽

Welding Parameters ◽

Cold Metal Transfer ◽

Cmt Welding ◽

Mechanical Properties And Corrosion ◽

Cold Metal

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.

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Effect of Zn Vaporization on Wetting of Al-galvanized Steel in Cold Metal Transfer Process

Journal of Iron and Steel Research International ◽

10.1016/s1006-706x(16)30089-9 ◽

2016 ◽

Vol 23 (6) ◽

pp. 566-572 ◽

Cited By ~ 5

Author(s):

Qiao-li Lin ◽

Gao-jun Mao ◽

Qian Huang ◽

Rui Cao ◽

Jian-hong Chen

Keyword(s):

Transfer Process ◽

Metal Transfer ◽

Galvanized Steel ◽

Cold Metal Transfer ◽

Cold Metal

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Weldability and Distortion of Mg AZ31-to-Galvanized Steel SPOT Plug Welding Joint by Cold Metal Transfer Method

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4034009 ◽

2016 ◽

Vol 139 (2) ◽

Cited By ~ 4

Author(s):

R. Cao ◽

Q. W. Xu ◽

H. X. Zhu ◽

G. J. Mao ◽

Q. Lin ◽

...

Keyword(s):

Mild Steel ◽

Weld Metal ◽

Base Metal ◽

Metal Transfer ◽

Galvanized Steel ◽

Feed Speed ◽

Process Variables ◽

Cold Metal Transfer ◽

Wire Feed Speed ◽

Cold Metal

In this study, cold metal transfer (CMT) plug welding of 1 mm thick Mg AZ31 to 1 mm thick hot-dipped galvanized mild steel (i.e., Q235) was studied. Welding tests were performed and the process variables optimized with Mg AZ61 wire and 100% argon shielding gas for a plug weld located in the center of the 25 mm overlap region. It was found that it is feasible to join 1 mm thick Mg AZ31 workpiece to 1 mm thick galvanized mild steel using CMT plug welding. The optimized process variables for CMT plug welding Mg AZ31-to-galvanized mild steel were a wire feed speed of 10.5 m/min, a predrilled hole with a diameter of 8 mm in Mg AZ31 workpiece and a welding time of 0.8 s. CMT plug welded Mg AZ31-to-galvanized mild steel joints were composed of the fusion zone between Mg AZ31 base metal and Mg weld metal, Mg weld metal (i.e., combined base metal, filler wire and Zn coating), and the brazing interface between magnesium weld metal and galvanized mild steel. The brazing interface mainly consisted of Al, Zn, Mg, Si intermetallic compounds and oxides (i.e., Fe3Al, Mg2Si, MgZn, and MgZn2), and magnesium solid solution. The static strength of CMT welded-brazed Mg AZ31-galvanized steel was determined primarily by the strength and area of the brazed interface and thickness of the intermetallic reaction layer.

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Complex Behavior of Droplet Transfer and Spreading in Cold Metal Transfer

Shock and Vibration ◽

10.1155/2020/6650155 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Shuai Yang ◽

Yanfeng Xing ◽

Fuyong Yang ◽

Juyong Cao

Keyword(s):

Control Method ◽

Short Circuit ◽

Continuous Process ◽

Welding Process ◽

Intelligent Manufacturing ◽

Metal Transfer ◽

Droplet Spreading ◽

Cold Metal Transfer ◽

Cmt Welding ◽

Cold Metal

In intelligent manufacturing, an intelligent control method of welding process is an important process of intelligent welding manufacturing technology (IWMT). Metal transfer is a key factor to control the welding process. Metal transfer and droplet spreading are of vital importance for welding formation. A new theoretical model of cold metal transfer (CMT) in short-circuit transfer mode is proposed in this paper. In this model, the CMT welding process is regarded as a continuous process of arc heating, mass transfer, short-circuit, and spreading, and the relations between these processes are analyzed. The calculation equations used by the model can analyze the welding formation clearly and simplify the complex welding process into continuous physical behavior. The predicted welding width shows good agreement with the measurement results. The mechanism of increased welding width is also comprehensively analyzed. Results have a certain guiding effect on aluminum alloy welding process control.

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