scholarly journals Stability and Heat Input Controllability of Two Different Modulations for Double-Pulse MIG Welding

2019 ◽  
Vol 9 (1) ◽  
pp. 127 ◽  
Author(s):  
Jiaxiang Xue ◽  
Min Xu ◽  
Wenjin Huang ◽  
Zhanhui Zhang ◽  
Wei Wu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Heat Input ◽  
Double Pulse ◽  
Fish Scale ◽  
Input Energy ◽  
Mig Welding ◽  
Pulse Modulation ◽  
Welding Arc ◽  
Input Control ◽  
Welding Processes

Aluminum alloy welding frequently experiences difficulties such as heat input control, poor weld formation, and susceptibility to pore generation. We compared the use of two different modulations for double-pulse metal inert gas (MIG) welding to reduce the heat input required to generate oscillations in the weld pool. The stabilities of rectangular wave-modulated and trapezoidal wave-modulated double-pulse MIG welding (DP-MIG and TP-MIG) were analyzed by examining their welding processes and weld profiles. We found that the transitional pulse in TP-MIG welding results in smoother current transitions, softer welding arc sounds, and a highly uniform fish-scale pattern. Therefore, TP-MIG welding is more stable than DP-MIG welding. The effects of these double-pulse modulation schemes on welding input energy are presented. We propose methods for reducing welding input energy by varying the number of pulses or the pulse base time of low-energy pulse train while keeping the welding current and welding arc stable and unchanged. Compared to DP-MIG welding, TP-MIG welding reduces the input energy by 12% and produces finer grain sizes, which increases weld hardness. Therefore, TP-MIG welding offers a new approach for heat input control in DP-MIG welding of aluminum alloys. The results of this work are significant for aluminum alloy welding.

scholarly journals Double-Pulse Triple-Wire MIG Welding of 6082-T6 Aluminum Alloy: Process Characteristics and Joint Performances

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1388
Author(s):  
Ke Yang ◽  
Fei Wang ◽  
Hongbing Liu ◽  
Peng Wang ◽  
Chuanguang Luo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
High Efficiency ◽  
Welding Process ◽  
Pulse Frequency ◽  
Double Pulse ◽  
Fish Scale ◽  
Mig Welding ◽  
Process Characteristics ◽  
Pulse Welding

High-efficiency and high-quality welding has always been the focus of welding research. This article proposes a novel double-pulse, triple-wire MIG welding process for the welding of 6082-T6 aluminum alloy. The process characteristics of welding arc and droplet transfer were studied, and the performances of weld formation, morphology, hardness, and tensile strength were tested for the 1 Hz, 3 Hz, and 5 Hz double-pulse welding and normal-pulse welding. It was found that in the welding process, the pulsed arc steadily alternated among three welding wires without arc interruption, and the arc length changed periodically with the double-pulse frequency. The droplets transferred with a stable one-pulse-one-drop mode. Besides, a proper double-pulse frequency, e.g., 3 Hz in this case, was conducive to forming good welds with regular fish-scale patterns and no pores. The tensile strength of the joint could reach 64% of the base material’s tensile strength, and its fracture belonged to plastic fracture, which occurred in the HAZ. This new welding method will have great potential in aluminum alloy welding.

Comparison on welding mode characteristics of arc heat source for heat input control in hybrid welding of aluminum alloy

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540016
Author(s):  
Moo-Keun Song ◽  
Jong-Do Kim ◽  
Jae-Hwan Oh
Keyword(s):  
Experimental Study ◽  
Aluminum Alloy ◽  
Heat Source ◽  
Laser Welding ◽  
Heat Input ◽  
Heat Sources ◽  
Hybrid Welding ◽  
Input Control ◽  
Mode Characteristics ◽  
Pulsed Arc

Presently in shipbuilding, transportation and aerospace industries, the potential to apply welding using laser and laser-arc hybrid heat sources is widely under research. This study has the purpose of comparing the weldability depending on the arc mode by varying the welding modes of arc heat sources in applying laser-arc hybrid welding to aluminum alloy and of implementing efficient hybrid welding while controlling heat input. In the experimental study, we found that hybrid welding using CMT mode produced deeper penetration and sounder bead surface than those characteristics produced during only laser welding, with less heat input compared to that required in pulsed arc mode.

Double Pulse Low-Frequency Modulation for High-Power Double-Wire Pulsed GMAW

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Kaiyuan Wu ◽  
Zhuoyong Liang ◽  
Tong Yin ◽  
Zuwei He ◽  
Min Zeng
Keyword(s):  
High Power ◽  
Frequency Modulation ◽  
Heat Input ◽  
Energy Input ◽  
Modulation Frequency ◽  
Low Frequency ◽  
Double Pulse ◽  
Weld Quality ◽  
Weld Width ◽  
Input Control

A double pulse low-frequency modulation method was proposed to improve heat input control and enhance weld quality during high-power double-wire pulsed gas metal arc welding (GMAW). By constructing a mathematical model, relationships between parameters of double pulse low-frequency modulation and energy input were analyzed. A correction coefficient was added to overcome physical characteristics of charging and discharging in a welding circuit. Thus, qualitative relationships between parameters of double pulse low-frequency modulation and energy input were described more accurately. Bead-on-plate welding experiments were conducted in a synchronous phase mode. A stable welding process was achieved and perfect weld bead shapes were acquired. Modulation frequency imposed a significant effect on both weld width and penetration, while modulation duty cycle had a significant effect on penetration and little effect on weld width. Modulation frequency significantly influenced refinement of grain size. Weak and strong pulses of low-frequency modulation improved heat input control, strengthened stirring action of double pulse on weld pool, and enhanced fluidity of molten metals, thereby contributing to optimization of weld quality.

Weld Width Control System for Pulsed MIG Welding of Aluminum Alloy

2011 ◽  
Vol 299-300 ◽  
pp. 908-911
Author(s):  
Li Hui Lu ◽  
Ding Fan ◽  
Jian Kang Huang ◽  
Ming Zhu ◽  
Yu Shi
Keyword(s):  
Aluminum Alloy ◽  
Control System ◽  
Welding Process ◽  
Pulse Method ◽  
High Energy ◽  
Double Pulse ◽  
Mig Welding ◽  
Heat Accumulation ◽  
Weld Width ◽  
Vision Sensing

Due to strong heat accumulation and low surface tension of aluminum alloy, weld width will become wider, even subsidence in pulsed MIG welding process of aluminum alloy at constant parameters. A variable double-pulse method for weld width control is proposed. Weld width control is realized by changing double-pulse duty cycle that is the ratio of high-energy pulse time in a double-pulse cycle to adjust heat input based on the vision sensing for weld width. A rapid prototyping control system is built on the basis of vision sensing and xPC Target real-time environment. Then variable double-pulse MIG welding process test is done and proves the feasibility of the control scheme. On this basis, weld width control test in pulsed MIG welding of aluminum alloy is carried out and obtains a good weld with beautiful formation and uniform weld width. The results show that weld width control can be realized well with the variable double-pulse method in pulsed MIG welding of aluminum alloy.

Numerical Simulation and Experiment Analysis of MIG Welding for Aluminum Alloy Extrusion

2012 ◽  
Vol 430-432 ◽  
pp. 1311-1314
Author(s):  
Zheng Zhi Luo ◽  
Yi Su Pan
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Three Dimensional ◽  
Welding Process ◽  
Element Model ◽  
Mig Welding ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Welding Processes ◽  
Aluminum Alloy Extrusion

Welding characteristics of MIG welding for aluminum alloy extrusions are studied. In this article, the aluminum alloy is EN AW-6005A. The welding heat source and the welding processing of aluminum alloy extrusions are discussed. A three dimensional finite element model has been developed to dynamically simulate the welding process. The investigations focus on the comparison the welding heat resource of simulation and section of the experiments parts. And the residual stress of numerical simulation and tests are compared. It’s help to optimize the MIG welding processes and improve the welding quality for aluminum alloy extrusion.

ANALYSIS AND COMPARISON OF ALUMINUM ALLOY WELDED JOINTS BETWEEN METAL INERT GAS WELDING AND TUNGSTEN INERT GAS WELDING

2015 ◽  
Vol 22 (06) ◽  
pp. 1550079 ◽  
Author(s):  
LEI ZHAO ◽  
YINGCHUN GUAN ◽  
QIANG WANG ◽  
BAOQIANG CONG ◽  
BOJIN QI
Keyword(s):  
Aluminum Alloy ◽  
Inert Gas ◽  
Xps Analysis ◽  
Mig Welding ◽  
Tungsten Inert Gas Welding ◽  
Addition Method ◽  
Metal Inert Gas Welding ◽  
The Difference ◽  
Welding Processes ◽  
And Tungsten

Surface contamination usually occurs during welding processing and it affects the welds quality largely. However, the formation of such contaminants has seldom been studied. Effort was made to study the contaminants caused by metal inert gas (MIG) welding and tungsten inert gas (TIG) welding processes of aluminum alloy, respectively. SEM, FTIR and XPS analysis was carried out to investigate the microstructure as well as surface chemistry. These contaminants were found to be mainly consisting of Al 2 O 3, MgO , carbide and chromium complexes. The difference of contaminants between MIG and TIG welds was further examined. In addition, method to minimize these contaminants was proposed.

scholarly journals Effect of Double-Pulse Characteristics on Weld Bead Formation and Mechanical Properties in Metal Inert Gas Welding

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 995
Author(s):  
Xiao Liu ◽  
Xiaoyan Yu ◽  
Jiaxiang Xue
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Weld Bead ◽  
Double Pulse ◽  
Welding Parameters ◽  
Mig Welding ◽  
Bead Formation ◽  
Weld Bead Formation ◽  
Metal Inert Gas Welding ◽  
Pulse Characteristics

Aluminum alloy has been widely used due to its excellent workability, and double-pulse metal inert gas welding (MIG) has become a popular technique in aluminum alloy welding. In this study, a cross-complementary test was performed to study the effect of double-pulse characteristics on weld bead formation and mechanical properties in MIG welding. The test was carried out on an AA6061 aluminum alloy using flat overlaying welding. After welding, the micro-metallographic structure and macro-mechanical performance of the weld bead were explored. The test results showed that the two methods of increasing the base current amplitude or the low-frequency of the current effectively enhanced the oscillation of the molten pool, refined the grain size of the fusion zone, and improved the mechanical properties of the weld. Additionally, by comparing the macroscopic photograph of the specimen and the corresponding welding parameters in the test, the formation characteristics of the bead’s fish-scale pattern in double-pulse MIG welding were found when appropriate welding parameters were adopted and weld bead formation was good. This test result provides a strong scientific basis for the selection of welding parameters in the actual promotion and application of double-pulse MIG welding.

scholarly journals Development of laser welding of high strength aluminium alloy 2024-T4 with controlled thermal cycle

2020 ◽  
Vol 326 ◽  
pp. 08005
Author(s):  
Mete Demirorer ◽  
Wojciech Suder ◽  
Supriyo Ganguly ◽  
Simon Hogg ◽  
Hassam Naeem
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Heat Input ◽  
Thermal Cycle ◽  
Laser Beam Welding ◽  
Base Material ◽  
High Strength ◽  
Cooling Rates ◽  
Aa 2024 ◽  
Welding Processes

An innovative process design, to avoid thermal degradation during autogenous fusion welding of high strength AA 2024-T4 alloy, based on laser beam welding, is being developed. A series of instrumented laser welds in 2 mm thick AA 2024-T4 alloys were made with different processing conditions resulting in different thermal profiles and cooling rates. The welds were examined under SEM, TEM and LOM, and subjected to micro-hardness examination. This allowed us to understand the influence of cooling rate, peak temperature, and thermal cycle on the growth of precipitates, and related degradation in the weld and heat affected area, evident as softening. Although laser beam welding allows significant reduction of heat input, and higher cooling rates, as compared to other high heat input welding processes, this was found insufficient to completely supress coarsening of precipitate in HAZ. To understand the required range of thermal cycles, additional dilatometry tests were carried out using the same base material to understand the time-temperature relationship of precipitate formation. The results were used to design a novel laser welding process with enhanced cooling, such as with copper backing bar and cryogenic cooling.

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