scholarly journals Effect of heat input on interfacial characterization of the butter joint of hot-rolling CP-Ti/Q235 bimetallic sheets by Laser + CMT

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Z. Y. Zhu ◽  
Y. L. Liu ◽  
G. Q. Gou ◽  
W Gao ◽  
J. Chen
Keyword(s):  
Carbon Steel ◽  
Heat Input ◽  
Composite Structures ◽  
Chemical Elements ◽  
Long Distance ◽  
Cold Metal Transfer ◽  
Cmt Welding ◽  
Q235 Carbon Steel ◽  
Cold Metal ◽  
Cp Ti

AbstractComposite structures made of 2 mm-thick titanium and 10 mm-thick carbon steel are widely used in infrastructures such as long-distance gas transportation. However, cracking, which is caused by intermetallic compounds (ICs), is a dominate failure mode in welds of this structure. Thus, a common way to improve the in-service life of is reduce the number of ICs. In this paper, we employ a novel hybrid welding method to fabricate composite structures of TA2 titanium and Q235 carbon steel. Specifically, Ti and carbon steel is welded by laser and double Cold Metal Transfer (CMT) welding, respectively. The microstructure near the interface of Ti and steel is then examined using SEM, EBSD, EDS, with emphasis on the ICs in terms of chemical elements and morphologies. Results show that FeTi and Fe2Ti are the main ICs near the interface, and responsible for the failure of the welds. The effect of welding heat input on the formation of ICs is investigated as well. Results show that ICs are smaller when the heat input is low. Under low heat input circumstance, the tensile strength of the weld can reach up to 420 MPa.

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

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.

Cold Metal Transfer Spot Joining of AA6061-T6 to Galvanized DP590 Under Different Modes

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
HaiYang Lei ◽  
YongBing Li ◽  
Blair E. Carlson ◽  
ZhongQin Lin
Keyword(s):  
Heat Input ◽  
Mechanical Performance ◽  
Welding Process ◽  
High Strength ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Spot Joining ◽  
Predrilled Hole ◽  
Joint Quality ◽  
Cold Metal

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.

scholarly journals Influence of Preheating Temperature on Cold Metal Transfer (CMT) Welding–Brazing of Aluminium Alloy/Galvanized Steel

2018 ◽  
Vol 8 (9) ◽  
pp. 1659 ◽  
Author(s):  
Youqiong Qin ◽  
Xi He ◽  
Wenxiang Jiang
Keyword(s):  
Aluminium Alloy ◽  
Interfacial Layer ◽  
Metal Transfer ◽  
Galvanized Steel ◽  
Load Force ◽  
Cold Metal Transfer ◽  
Preheating Temperature ◽  
Cmt Welding ◽  
Brazed Joint ◽  
Cold Metal

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.

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

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.

scholarly journals Complex Behavior of Droplet Transfer and Spreading in Cold Metal Transfer

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.

Heat input, intermetallic compounds and mechanical properties of Al/steel cold metal transfer joints

2019 ◽  
Vol 272 ◽  
pp. 40-46 ◽  
Author(s):  
Jin Yang ◽  
Anming Hu ◽  
Yulong Li ◽  
Peilei Zhang ◽  
Dulal Chandra Saha ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
Heat Input ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Cold Metal
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