Welding Energy Research Articles

Field shaper-based solutions to the bulging problem in magnetic pulse spot welding of dissimilar metal plates

Magnetic pulse spot welding based on a field shaper can effectively achieve spot welding of dissimilar metal plates by using the multi-turn flat coil and magnetic gathering through the field shaper. Through existing experimental research, it has been found that when using this method for welding, there will be a serious bulging problem in the center of the welding area, which will affect the flatness and aesthetics of the welding area, thereby affecting its application range. To solve this problem, this work proposes two different welding methods for welding dissimilar AA1060 aluminum and SS304 steel plates with a thickness of 1 mm: one based on the center opening of the flying plate and the other based on the pre-deformation of the flying plate. The causes of bulging and the effects of discharge voltage, welding gap, and inner hole radius of the field shaper on bulging size were studied. The cross-sectional morphology and mechanical properties of welded joints obtained by two welding methods were studied through numerical simulation, cross-sectional analysis, and tensile testing. The results indicated that both welding methods can successfully eliminate the bulging problem, and the point welding method based on the center opening of the aluminum plate can also reduce the minimum welding energy required for effective welding and improve welding efficiency. In addition, microscopic analysis results showed that a waveform composite interface was formed at the welding interface of the joint, and the connection performance of the welded joint was good. These two welding methods can also be extended to the welding of other dissimilar metal plates, which is of great significance for the industrial application of magnetic pulse spot welding technology based on field shaper.

Bonding strength of short carbon fiber reinforced PA6 composites ultrasonic welding joints

AbstractShort carbon fiber composites have high specific modulus, high specific strength and excellent formability, which are suitable for short‐term and environmentally friendly ultrasonic welding. In this study, ultrasonic welding experiments were conducted on short carbon fiber reinforced PA6 composites using a servo‐driven non‐metallic ultrasonic welder. The weld specimens were analyzed for spot weld morphologies, interfacial bonding strength, failure modes and compressive shear fracture to establish the correlation between weld energy and weld quality. The results indicate that when the welding energy is 450 J, the short carbon fibers are interlaced at the interface, which has a pinning effect, thereby enhancing the joint strength reaching 2990 N, and the welding efficiency reaches 46%. Besides, the compressive shear section is divided into regions. The proportion of heat and area in different compressive shear regions are quantitatively analyzed, and the calculation model of joint strength is proposed. Meanwhile, the correlation between welding energy and its correlation, as well as three different shear failure modes, is obtained. This work is helpful for the optimization of carbon fiber reinforced thermoplastic (CFRTP) ultrasonic welding process parameters and the evaluation of joint strength.Highlights A special fixture for ultrasonic welding was designed to optimize the welding energy process of ultrasonic welding CFRTP, and the properties of ultrasonic welded joints were analyzed. When the welding energy is 450 J, a high shear strength welded joint of 2990 N was successfully prepared. The shear fracture of the welded joint was successfully obtained by designing a special clamp for compression shearing. The welding area was qualitatively divided according to the temperature measurement results of the interface center. In addition, the heat and area ratio of different zones in the compression‐shearing area under different welding energy were quantitatively analyzed, and the calculation model of joint strength was proposed. At the same time, the welding energy and its correlation, as well as three different shear failure modes were obtained. The short fiber distribution characterization and pores effect on the joint's strength were analyzed. The appearance of porosity defects has a significant weakening effect on the welded joint.

Achieving superior aluminum-steel dissimilar joining via ultrasonic spot welding: Microstructure and fracture behavior

High-strength dissimilar welded joints of AA2024-T3 alloy with an AA1230 coating and galvanized high-strength low-alloy (HSLA) steel were attained through ultrasonic spot welding (USW) in this study. The tensile lap shear failure loads over a welding energy range between 2000 J and 3000 J were observed to meet or surpass the values specified in the AWS D17.2 standard. The highest average tensile lap shear strength was obtained to be ∼169 MPa due to the formation of a ∼30–70 μm thick Al-Zn diffusion layer without the presence of intermetallic compounds. The substrate failure from the softer AA1230 coating on the AA2024 side under tensile loading and cyclic loading at higher cyclic loads was observed, which reflected a robust sticking capability. The partial failure from AA1230 coating consisted of characteristic shear dimples, allowing high plasticity upon shear deformation. While the 1000 J welds failed mainly via substrate failure from AA1230 and transverse through-thickness (TTT) cracking in AA2024, the cohesive failure across the Al-Zn diffusion layer and adhesive failure from the Al-Fe-intermetallic/Al-Zn-diffusion layer interface were observed in the welds made at 3000 J, corresponding to the superior bonding strength and longer fatigue life.

On the Influence of Welding Parameters and Their Interdependence During Robotic Continuous Ultrasonic Welding of Carbon Fibre Reinforced Thermoplastics.

Ultrasonic welding of fibre-reinforced thermoplastics is a joining technology with high potential for short welding times and low energy consumption. While the majority of the current studies on continuous ultrasonic welding have so far focused on woven reinforcements, unidirectional materials are preferred for highly loaded aerospace components due to their better mechanical performance. Therefore, this paper investigates the influence and interdependence of the welding speed, amplitude, and energy director thickness on the weld quality of adherends made of unidirectional composites. The quality of the welded joints is assessed by a single-lap shear strength and fracture surface analysis complemented by the microscopic analysis of cross-sections and comparison to a co-consolidated reference. The results showed that the welding process is highly affected by changing welding speeds for a given amplitude. Furthermore, while lower amplitudes lead to significant scatter in the welding quality, higher amplitudes result in increased heating rates and a fully molten energy director even for high welding speeds. Nevertheless, insufficient consolidation at high welding speeds results in porosity in the weld line. Finally, it was observed that thicker, and therefore more compliant, energy directors lead to more uniform melting of the energy director and less deviation in the weld quality for a wider range of welding speeds.

Analysis of projection welding in relation to the non-parallelism of electrodes

The article contains the analysis of projection welding in relation to the non-parallel location (non-parallelism) of electrodes. For a thin-walled flat element, e.g., sheet metal with two embossed projections, calculations were conducted for different angles between the upper electrode and the lower electrode. The calculation involved the use of the SORPAS 3D software. The analysis included the distribution of temperature, power density, electrode displacement, the volume of molten metal in the weld nugget, nugget diameters, and energy supplied to the weld. The article presents the comparison of results obtained for various angles between the electrodes of the welding machine. The results of numerical calculations were verified experimentally through technological welding tests and destructive tests (peeling/metallographic). The convergence of the experimental and numerical results was satisfactory. The tests involved a typical element used in the automotive industry, i.e., a nut with two embossed projections in the flat part. The article represents quite an innovative new approach to multiple-projection welding from a numerical calculation point of view. Such an approach allows the researcher to identify the phenomena taking place in the process. The article also presents a new approach to the analysis of multi-projection welding as regards the non-parallelism of electrodes. The results enabled the determination of phenomena taking place in the multi-projection welding process as well as the boundary conditions in relation to which the process became improper (unstable).

Microstructure and mechanical properties of ultrasonically welded aluminum to Zn–Mg–Al coated and uncoated mild steels

The gaining popularity of aluminum alloys in the automotive industry demand the development of energy efficient joining methods of Al with other metals such as steel. Among such joining methods, ultrasonic welding is advantageous because it is cost effective and prevents metallurgical defects because of the low welding energy involved. This study evaluates the microstructural changes and mechanical properties of dissimilar ultrasonic welding of Al to Zn–Mg–Al-coated and uncoated mild steels. Various intermetallic compounds (IMCs), such as FeAl3, and Fe2Al5 with different thicknesses and morphologies were observed at the joint interfaces. The Al-to-Zn-Mg-Al-coated steel exhibited mechanical properties that are superior to those of Al-to-uncoated mild steel. The results are discussed in terms of microstructure evolution, joint characteristics, and interfacial reactions in the welds. This study contributes to the understanding of the mechanisms behind strong ultrasonic welding of dissimilar metals.

Microstructural Characterization of Friction Stir Welds of Aluminum 6082 Produced with Bobbin Tool.

This study utilized a bobbin tool to friction stir weld aluminum 6082 workpieces under two sets of process parameters: a tool rotation speed of 280 rev/min with a weld velocity of 280 mm/min (280/280) and a tool rotation speed of 450 rev/min with a weld velocity of 450 mm/min (450/450). The weld microstructures were characterized through optical microscopy utilizing polarized light and through transmission electron microscopy (TEM) and scanning electron microscopy (SEM) coupled with chemical analysis by energy dispersive spectroscopy and electron back scatter diffraction. The microstructural studies were supplemented by hardness measurements (Vickers) performed on the same sections as the metallographic examinations. The produced weldments were free from cracks and any discontinuities. Fine, equiaxed grains that were several microns in size characterized the stir zones (SZs), and the advancing (AS) and retreating (RS) sides revealed distinct microstructural features. On the AS, the transition from the thermo-mechanically affected zone to the SZ was well defined and sharp, but on the RS, the transition appeared as a continuous, gradual change in microstructure. The lower weld energy (280/280) produced lower hardness in the stir zone than the higher energy weld (450/450), ~95 HV1 versus ~115 HV1; however, the 280/280 welds showed higher tensile strengths than the 450/450 welds, ~238 MPa as opposed to ~172 MPa. These behaviors in mechanical performance correlated with the temperature histories produced by each set of weld parameters in relation to the precipitation behavior of the alloy. The fracture characteristics of the weldments were notably different with the 450/450 sample fracturing in a quasi-brittle manner with slight plastic deformation and the 280/280 sample fracturing ductilely. A numerical simulation supported the investigation by elucidating the temperature and material flow behavior during the joining process.

Optimization of gas metal arc welding parameters for dissimilar steel welds: A case study on duplex stainless steel 2205 and stainless steel 316L

The significance of welded connections in steel structures necessitates precise structural designs and processing adaptations to ensure robust mechanical strength and durability. Gas metal arc welding (GMAW) employing controlled curves presents advantages over conventional methods, offering enhanced weld bead properties, improved aesthetics, and reduced thermal inputs. This research investigates the impact of GMAW parameters using controlled curves on the microstructure and geometry of welds between dissimilar structural steels—duplex stainless steel 2205 and stainless steel 316L grade 50—commonly employed in construction. The aim is to optimize the GMAW welding process with controlled curves and surface tension transfer between these dissimilar steels. Through a 23-factorial experimental design encompassing feed speed (Va), arc focus (FC), and peak-to-base amplitude (APB), the study examines welding energy, geometry, deposition efficiency, microstructure, microhardness, tensile strength, and corrosion properties. Optimal welding energy fosters refined microstructures and uniform hardness, aiding in predicting weld throat area. Higher energy levels expand the heat-affected zone and coarse grains, while lower energies escalate variability. Predictive models facilitate fine-tuning welding energy and throat area for desirable properties and penetration while minimizing disruptions. This process optimization can be achieved by employing derived equations that limit welding energy and curve parameters, striking a desired balance between cost, structural integrity, and reliability.

A novel multi-loss dynamic fusion-enhanced image segmentation model for welding spatter measurement

Quantitative detection of welding spatter is not only critical for evaluating and optimizing welding energy consumption, but also significant for improving welding quality. Inspired by the welder's visual estimation of the amount of spatter, a novel welding spatter measurement method based on image segmentation is proposed. Considering the challenges of welding spatter such as small object, aggregation, and unclear boundary, four loss functions, namely, Focal loss, Dice loss, Boundary loss, and Count loss, are designed to achieve global optimization for complex welding spatter. Furthermore, for the different spatter characteristics with different optimization difficulties, a multi-loss dynamic fusion method with differential optimization capability is designed. Finally, a welding spatter segmentation dataset is established and a comprehensive ablation and comparison test of the proposed methodology is carried out. The results indicate that the proposed method has an average F1-score metric of 83.52 % and a mean intersection over union metric of 75.11 %. These findings suggest the potential for vision-based quantitative estimation of welding spatter.

Microstructure and mechanical properties of resistance spot welded dissimilar aluminum/steel joints fabricated using high entropy alloy as interlayer

To improve the welding quality of Al/steel joint during resistance spot welding (RSW) process, a CoCrFeNiMn high entropy alloy (HEA) sheet was employed to be an interlayer between aluminum alloy and high strength steel parent metal sheets. Through a series of comparative studies and analyses, the Al/steel spot welded joint obtained from the process with the HEA interlayer had a larger aluminum nugget diameter and thinner intermetallic compound (IMC) layer when compared to a conventional RSW process. When the thicknesses of two parent metal sheets were 1.0 mm or 1.5 mm, the aluminum nugget diameter of the Al/steel spot welded joint with the HEA interlayer were 4.904 mm and 5.962 mm, and respectively increases by 28.41% and 31.32% compared to a conventional RSW process. For the 1.5 mm of the thickness of the parent metal sheets, the HEA interlayer can make the layer thicknesses at the Al/steel faying interface decrease from 3.2 μm to 1.3 μm. Also, adding the HEA interlayer could induce more welding heat energy respectively by 30.74% and 30.34%, and significantly improve the lap-shear strength of the joint by 56.95% and 52.09% for two thicknesses of the parent metal sheets. Even increasing welding current of the process without HEA interlayer to make its calculated welding heat energy the same as that with HEA interlayer, the Al/steel joint obtained from the process with HEA interlayer still had a higher lap-shear strength. In addition, by seriously observing and analyzing the fracture surfaces obtained from processes with and without the HEA interlayer, it could be concluded that the HEA interlayer could improve the fracture mode of the Al/steel joint from interfacial fracture to button fracture, so the quality of the Al/steel joint could be improved. This work can supply an effective method to improve the dissimilar metals welding process.

Influence of submerged arc welding process parameters and metallurgical behaviour in a thick carbon steel section for boiler application

AbstractThe aim of the research is to investigate the weldability of thick sections of carbon steel using submerged arc welding with varying process parameters. The experimental design for joining thick carbon steel involves manipulating input weld process parameters such as current (A), voltage (V), weld speed (mm/h), and weld electrode diameter (mm). The quality of the weld material is assessed based on transformations in microstructure, weld hardness measured by Brinell hardness number, and tensile strength (MPa). It is crucial to note that the grain structure and metallurgical behavior of other hard materials may differ significantly. The presence of carbon in the ferrite phase has led to the formation of bainite, martensite, and composites of martensite and austenite within the weld zone, as confirmed by high‐resolution microscopy. The weldment‘s hardness has increased from 242.5 HV 30 in the base metal to 316.4 HV 30 in the weldment due to metallurgical alterations in the microstructure. Weld energy input emerges as the primary factor influencing weld quality. With increasing weld current and voltage, there is a corresponding increase in the joined metal, resulting in improved characteristics in the weld structure, particularly at maximal energy input and welding speed. In the context of boiler applications, understanding the weldability of thick carbon steel sections is paramount for ensuring structural integrity and longevity under high‐temperature and high‐pressure conditions. The optimized welding parameters identified in this study can contribute to enhancing the reliability and performance of boilers, thereby promoting safety and efficiency in industrial settings.

Effects of welding displacement and energy director thickness on the ultrasonic welding of epoxy-to-polyetherimide based hybrid composite joints

This study aimed to develop robust thermoplastic-to-thermoset composite joints upon an ultrasonic welding process. The carbon fiber/epoxy composite was topped with a layer of polyetherimide (PEI) film by a co-curing process, making it “weldable” with the carbon fiber/PEI composite. The effects of welding displacement and thickness of the energy director (ED) on the welding process of the epoxy-to-PEI hybrid composite joints were investigated. The experimental results demonstrated that an optimal welding displacement existed for the best welding quality, whose value depended on the ED thickness. Given a certain ED thickness, the lap-shear strength (LSS) of the hybrid joints increased to a maximum value and then decreased as the welding displacement increased. By optimizing the displacement and ED thickness, a maximum LSS of 39.4 MPa was obtained for the hybrid joints. In which case, the level of the defects within the welding line was minimized, and the joints failed cohesively within the composite substrates.

Strength and Fracture Toughness of TIG- and Laser-Welded Joints of Low Carbon Ferritic Steels.

This paper presents the results of experimental testing of joints welded using conventional TIG and laser methods. The welded components were sheets of the low-carbon steels 13CrMo4-5 and 16Mo3. Welded joints were made using different levels of linear welding energy. In the case of laser welding, a bifocal beam with longitudinal positioning of the focal lengths in relation to the welding direction was used. Experimental tests on welded joints included a bending test and determination of hardness distribution, mechanical properties, and fracture toughness, as well as microstructural research in the material of the various joint zones. Based on the determined strength characteristics, the true stress-strain relationships were defined, and a numerical model of the laser joints was developed in Abaqus 6.12-3. The modelled joint was subjected to loading to determine the most stressed areas of the joints. The numerical results were compared with those obtained using GOM's Aramis 3D 5M digital image correlation system. The system used made it possible to record displacements on the surface of the analysed joints in real time. Good agreement was obtained between the strain fields calculated numerically and those recorded using the Aramis 3D 5M video system. The numerical calculations provided information on the strains and stresses occurring inside the analysed joint during loading. It was found that the welded joints were characterised by increased hardness and high strength properties in relation to the base material. The bending test of the laser-welded joints gave a positive result-no cracks were observed on the face or root of the weld. The fracture toughness of the joint zones is slightly lower in relation to that of the base material, but no brittle fracture was observed.

Investigation of ultrasonic welding of CF/PA66 using nylon mesh energy directors

AbstractCarbon fiber reinforced polyamide 66 (CF/PA66) sheets are ultrasonically welded by applying nylon meshes as energy directors (EDs) in this paper. The influence of mesh dimensions is revealed by observing the joint formation process, joint mechanical performance, joint cross‐sectional morphology and joint failure mode. Results show that the joint formation process can be divided into wire flattening stage, ED spread stage, tight bonding stage, and mixing stage. The nylon mesh ED with moderate wire spacing, small wire diameter and small mesh area promotes better weld quality. Welding energy will be dispersed rather than concentrated if the mesh area is too large, resulting in reduced failure load. The joints exhibit two fracture modes: interfacial fracture (IF) and workpiece fracture (WF), and the fracture mode of the joints with nylon mesh EDs transits from IF to WF as the welding energy increases.Highlights Five types of nylon mesh are used as energy directors to join CF/PA66 sheets by ultrasonic welding. The influence of nylon mesh dimensions on the mechanical property and fracture mode of joints is investigated. The formation process of ultrasonically welded joints can be separated into wires flattening stage, ED spread stage, tight bonding stage, and mixing stage.

Mechanical characterization of ultrasonically welded CF/PEEK laminates by short beam shear test

Bond strength between composite plates has often been evaluated using single-lap shear tests, with the difficulty of having the characteristics of the entire bond area reflected in the results. To overcome this limitation, a short-beam shear test was performed in this study. The specimens were fabricated by ultrasonic welding using carbon fiber reinforced polyether ether ketone laminates as the adherend and a resin mesh. The effect on mechanical characterization was investigated by varying the thickness and stacking configuration of the adherend and the welding energy. The highest apparent interlaminar shear strength was observed when an approximately 3 mm thick adherend of the quasi-isotropic laminate was welded, and the strength was approximately 17% lower than that of non-welded laminates.

Ultrasonic welding of Cu cables bonding: Tensile, porosity and evolution of microstructure

Tensile strength, porosity and microstructure evolution of ultrasonic bonding for BVR2.5 Cu cables at different welding energies were investigated. By X-ray computed tomography and modification of the Johnson-Cook model, the predictive model of porosity was developed for the first time to assess joint strength. When the porosity was lower than 19%, the joint formed a good bond and reached the tensile strength of 585.7 ± 17.9 N. The maximum joint tensile strength was achieved at about 10% porosity. The Cu grains at the interface underwent plastic deformation, discontinuous dynamic recrystallisation and dynamic recovery to form a good bond. Interfacial grains are refined by ultrasonic vibrations, but the reduction of the porosity is the critical factor in improving joint strength.

Improving interfacial strength at room and elevated temperatures in ultrasonic welding of pure titanium: Interlayer-induced phase transformation and concentrated plastic deformation

Ultrasonic welding (USW) of Titanium (Ti) sheets presents several challenges, notably crack formation due to sliding friction. To overcome this problem, the present study applied USW to pure α-Ti sheets both with and without different interlayer metals (Al, Ni, and Fe). Al interlayer improved the strength at room temperature significantly to cause base metal fracture (1700 N) by inducing concentrated plastic deformation, facilitating bonding with Ti while minimizing damage. However, its strength decreased significantly at 150–300 °C, suggesting the limitation of using Al interlayer at elevated temperatures. Conversely, the Ni and Fe interlayers led to a two-phase strength development. This enhancement was due to β-phase transformation, which reduces the interfacial defects and generates a more pronounced β-stabilization effect. The Ni interlayer, which has a higher β-transus point (765 °C) and lower molybdenum equivalency, required a higher welding energy (1800 J) and longer diffusion time into Ti, resulting in a gradual increase in strength due to a slower β-Ti transformation. On the other hand, the Fe interlayer with a lower β-transus point relative to Ti (595 °C) achieved peak strength at a lower welding energy of 1200 J. Both Fe and Ni interlayers displayed only a slight decrease in strength (1500–1600 N) at 300 °C with base metal fracture, revealing better joint performance at higher temperatures. These insights suggest a strategical interlayer selection based on the operation temperature, where Al interlayers were advantageous for low-energy welding at room temperature application, Fe and Ni interlayers offer sufficient strength at elevated temperatures by facilitating the β-Ti formation.

Effect of Process Parameters on Welding Residual Stress of 316L Stainless Steel Pipe.

316L stainless steel pipes are widely used in the storage and transportation of low-temperature media due to their excellent low-temperature mechanical properties and corrosion resistance. However, due to their low thermal conductivity and large coefficient of linear expansion, they often lead to significant welding residual tensile stress and thermal cracks in the weld seam. This also poses many challenges for their secure and reliable applications. In order to effectively control the crack defects caused by stress concentration near the heat-affected zone of the weld, this paper establishes a thermal elastoplastic three-dimensional finite element (FE) model, constructs a welding heat source, and simulates and studies the influence of process parameters on the residual stress around the pipeline circumference and axial direction in the heat-affected zone. Comparison and verification were conducted using simulation and experimental methods, respectively, proving the rationality of the finite element model establishment. The axial and circumferential residual stress distribution obtained by the simulation method did not have an average deviation of more than 30 MPa from the numerical values obtained by the experimental method. This study also considers the effects of welding energy, welding speed, and welding start position on the pipe's circumferential and axial residual stress laws. The results indicate that changes in welding energy and welding speed have almost no effect on the longitudinal residual stress but have a more significant effect on the transverse residual stress. The maximum transverse residual stress is reached at a welding energy of 1007.4~859.3 J/mm and a welding speed of 6.6 mm/s. Various interlayer arc-striking deflection angles can impact the cyclic phase angle of the transverse residual stress distribution in the seam center, but they do not alter its cyclic pattern. They do influence the amplitude and distribution of the longitudinal residual stress along the circumference. The residual stress distribution on the surface of the pipe fitting is homogenized and improved at 120°.

Formation mechanisms and mechanical properties in aluminum cables and copper terminals ultrasonic welded joint

To fabricate highly reliable Al cables/Cu terminals components and elucidate the microstructure evolution of the joint during ultrasonic welding, ultrasonically welded structures of 50 mm2 Al cables and 2 mm-thick copper terminals were conducted at welding energies from 1200 J to 2800 J and an amplitude of 54.6 μm in this paper. As the welding energy increased, the degree of plastic deformation of the Al wires gradually increased, the microstructure of the Cu side remained basically unchanged, and the effective contact area of the Cu/Al interface was gradually enlarged, enhancing the coherence between the Al wires, and the Cu-Al interfacial structure changed from an unbonded area to continuous mechanical interlocking. Parallelly, the Al grains transformed from fine serrated to equiaxed and lamellar crystals driven by geometric dynamic recrystallization (GDRX), continuous dynamic recrystallization (CDRX), and dynamic recovery (DRV), forming distinct shear textures of B/B̅{111}<110>, Rt Goss{110}<110>, Rt Cube{001}<110> and the recrystallization texture F{111}<112>, and the content of shear textures increased from 2.9% to 17.4%. In addition, the tensile shear failure load of the joint reached 2962 N, which met the requirements of cable installations in the field of new energy vehicles (>1650 N). Fracture analysis showed the fracture location transitioned from the Cu-Al interface to the Al-Al interface with an increase in welding energy from 1600 to 2400 J. This work has theoretical guidance for the continuous promotion of vehicle light-weighting.

Simultaneous reduction in laser welding energy consumption and strength improvement of aluminum alloy joint by addition of trace carbon nanotubes

The widespread use of laser welded aluminum alloys in industrial production offers potential benefits to sustainable development and socio-economic progress. It simultaneously enhances the weld strength while reduces the energy consumption. Despite the promise of these alloys, research on reducing their energy consumption during laser welding is lacking. In this study, a dual effect of enhancing joint strength in 2A12 aluminum alloy and reducing energy consumption is achieved by the addition of trace carbon nanotubes (CNTs). The “welding efficiency" is defined and an energy consumption model for laser welding of aluminum alloys is developed. Next, the laser welding process with the addition of trace CNTs (LC) and the single laser welding process (LW) were compared and analyzed. The results indicate that adding trace CNTs can reduce energy consumption by more than 33 % and increase joint strength by 101 MPa. Furthermore, it is found that the LC process offers significant energy-saving advantages over other laser welding of aluminum alloy processes described in previous studies. These improvements is attributed to the increased laser absorption by the aluminum alloy induced by trace CNTs, as well as their residual presence in the joint, which acts as a strengthening medium. This work provides new insights and presents a novel approach for achieving low-carbon, high-quality welding of aluminum alloys.