Interfacial Microstructure of A6111/Steel Lap Joint Fabricated by Defocused Laser Beam Welding

2006 ◽  
Vol 519-521 ◽  
pp. 1119-1124 ◽  
Author(s):  
Kwang Jin Lee ◽  
Shinji Kumai ◽  
Nobuhiro Ishikawa ◽  
Kazuo Furuya
Keyword(s):  
Laser Beam ◽  
Heat Input ◽  
Laser Beam Welding ◽  
High Heat ◽  
Weld Interface ◽  
Interfacial Microstructure ◽  
Lap Joint ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Heat Input

Lap joining of A6111 alloy and steel (SPCC: Steel Plate Cold-rolled C) plates was performed using a defocused YAG laser beam. A detailed investigation was performed on the intermetallic compound (IMC) layer formed at the weld interface. Two representative joints fabricated under different welding conditions were selected and the effect of the welding conditions on the kind and morphology of the IMC was investigated using a transmission electron microscope (TEM). An electron diffraction pattern method was used to identify IMC. It was found that the morphology and kind of IMC formed at the weld interface were strongly affected by the welding conditions, in particular, by the amount of heat input during welding. The thickness of the IMC layer formed at the weld interface was about 1 μm and the average grain size of the IMC in the layer was less than 300 nm when the joining was carried out with a small amount of heat input. The IMC layer was composed of Fe3Al, FeAl, Al2Fe, Al5Fe2 and Al13Fe4 in this case. However, the thickness of the IMC layer was around 6 μm when the joining was carried out under high heat input conditions. In this case, the IMC layer was composed of coarse Al5Fe2 (5 μm) and Al13Fe4 (1 μm). Therefore, it is considered that the reduced bonding strength of the joint with a thick IMC layer is due not only to the overall morphology of the IMC layer but also to the formation of coarse Al-rich IMCs in the layer.

Laser Beam Welding of Aluminium: Process Optimisation to Achieve Hermetic Sealing for Electrochemical Energy System Containers

2012 ◽  
Vol 710 ◽  
pp. 632-637
Author(s):  
T.D. Mercy ◽  
Rahul Sharma ◽  
V.F. Kaladharan ◽  
K.P. Kamalakaran
Keyword(s):  
Laser Beam ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Laser Beam Welding ◽  
Lithium Ion ◽  
High Heat ◽  
Welding Parameters ◽  
Lithium Ion Cells ◽  
Hermetic Sealing ◽  
High Heat Input

Hermetic sealing is essential for long cycle life and calendar life of Lithium ion cells. Ingress of moisture and leaking of electrolyte in Lithium ion cells deteriorates the electrochemical performance. Nickel coated mild steel, Stainless steel, Aluminium and its alloys are generally used as case material. Pure Aluminium and Aluminium alloys are used to improve energy density of Lithium ion cells. High heat input is required for aluminium to obtain a sound weld because of the high thermal conductivity of the Aluminium. High heat input results in increased heat affected zone (HAZ) and transfer of heat into internal components during welding. Laser Beam Welding (LBW) results in very narrow heat affected zone (HAZ) and it is possible to have dissimilar metal welding. In the present work, experimental studies conducted to optimise the laser beam welding parameters for welding of Li-ion AA3003 cell case to lid without defects viz porosity and required weld strength. Hermeticity and strength of the weld bead were analysed in detail to ensure the adequacy of the process. It has been demonstrated that laser beam welding is a viable process for joining of cell case to its cover.

Low Heat Input Welding for Thin Steel Fabrication

2006 ◽  
Vol 22 (02) ◽  
pp. 105-109
Author(s):  
S.M. Kelly ◽  
R.P. Martukanitz ◽  
P. Michaleris ◽  
M. Bugarewicz ◽  
T. D. Huang ◽  
...  
Keyword(s):  
Laser Beam ◽  
Heat Input ◽  
Arc Welding ◽  
Process Development ◽  
High Heat ◽  
Hybrid Laser Arc Welding ◽  
Thin Steel ◽  
High Heat Input ◽  
Time Distortion ◽  
Buckling Distortion

As thinner members are used in marine construction, the use of conventional joining techniques results in significant angular and buckling distortion due to the inherent high heat input with these processes. Several low heat input alternatives, including laser beam, gas metal arc, and hybrid laser arc welding, are explored. The paper focuses on process development, real time distortion measurements, and implementation of these processes.

Low Heat Input Welding for Thin Steel Fabrication

2005 ◽  
Author(s):  
S. M. Kelly ◽  
R. P. Martukanitz ◽  
P. Michaleris ◽  
M. Bugarewicz ◽  
T. D. Huang ◽  
...  
Keyword(s):  
Laser Beam ◽  
Heat Input ◽  
Arc Welding ◽  
Process Development ◽  
High Heat ◽  
Hybrid Laser Arc Welding ◽  
Thin Steel ◽  
High Heat Input ◽  
Time Distortion ◽  
Buckling Distortion

As thinner members are used in marine construction, the use of conventional joining techniques result in significant angular and buckling distortion due to the inherent high heat input with these processes. Several low heat input alternatives, including laser beam, gas metal arc, and hybrid laser-arc welding are explored. The paper focuses on process development, real time distortion measurements and implementation of these processes.

Mechanical properties and fatigue behavior of CO2 laser beam welded armor steel joints

2020 ◽  
Vol 62 (7) ◽  
pp. 689-697
Author(s):  
Z. Balalan ◽  
F. Sarsilmaz ◽  
O. Ekinci
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Heat Input ◽  
High Strength ◽  
High Heat ◽  
Strength Properties ◽  
Welding Parameters ◽  
Test Results ◽  
Input Parameters ◽  
High Heat Input

Abstract Armor 500T steel used in armored military vehicles and marine vehicles were joined by CO2 laser beam welding method by applying three welding powers and two welding speeds under shielding argon atmosphere. From microstructure and microhardness results, under low laser welding power and high welding traveling speeds, microstructural transformation in the joining region of the performed welds occurred at a narrower distance as compared to other parameters, and it was determined that four regions formed independent of each other for each parameter group. Furthermore, it was determined that there is a gradual decrease in the microharness values of samples in which welding parameters cause heat input to decrease. The fatigue test results of all samples showed high strength properties in the parameters with high heat input. Additionally, tensile test results for all samples with high heat input parameters also exhibited high strength properties. Fracture at the intersection at high heat input parameters of a relatively ductile separation type occurred in HAZ whereas, at other parameters fracture occurred at the weld center and wide gap semi-brittle fracture behavior was observed. As a consequence, it was found that the most effective parameter as compared with laser welding power is laser welding traveling speed.

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.

Effects of oxygen content on microstructure and impact toughness of high heat input flux-cored wire weld metals

2018 ◽  
Vol 115 (4) ◽  
pp. 410
Author(s):  
Fengyu Song ◽  
Yanmei Li ◽  
Ping Wang ◽  
Fuxian Zhu
Keyword(s):  
Grain Size ◽  
Impact Toughness ◽  
Weld Metal ◽  
Oxygen Content ◽  
Heat Input ◽  
High Heat ◽  
Cored Wire ◽  
Weld Metals ◽  
High Heat Input ◽  
The Impact

Three weld metals with different oxygen contents were developed. The influence of oxygen contents on the microstructure and impact toughness of weld metal was investigated through high heat input welding tests. The results showed that a large number of fine inclusions were formed and distributed randomly in the weld metal with oxygen content of 500 ppm under the heat input condition of 341 kJ/cm. Substantial cross interlocked acicular ferritic grains were induced to generate in the vicinity of the inclusions, primarily leading to the high impact toughness at low temperature for the weld metal. With the increase of oxygen content, the number of fine inclusions distributed in the weld metal increased and the grain size of intragranular acicular ferrites decreased, which enhanced the impact toughness of the weld metal. Nevertheless, a further increase of oxygen content would contribute to a great diminution of the austenitic grain size. Following that the fraction of grain boundary and the start temperature of transformation increased, which facilitated the abundant formation of pro-eutectoid ferrites and resulted in a deteriorative impact toughness of the weld metal.

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