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Effect of shielding gas flow on welding process of laser-arc hybrid welding and MIG welding
摘要： The influence of shielding gas on welding process of laser-arc hybrid welding (LAHW) and metal inert-gas welding (MIG) was investigated by the computational fluid dynamics analysis (CFD) and high-speed photography. The results show that the process stability of MIG under high gas flow rate is poorer than that of LAHW. And the force of gas flow Fg can hinder the droplet transfer, whether MIG or LAHW. But the vaporization-induced recoil force Fv in LAHW helps to reduce this kind of hindrance and keep the process stability. Next, it can be found that the shielded gas flow mode in the main welding area cannot be changed significantly by increasing the shielding gas flow rate, while high gas flow rate can increase the area of high argon concentration and benefit the spread of molten metal.
关键词： Welding process,Computational fluid dynamics analysis,Laser-arc hybrid welding,MIG welding
更新于2025-11-28 14:24:20
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Laser cooling arc plasma effect in laser-arc hybrid welding of 316L stainless steel
摘要： Current laser-plasma interaction theory supports that the plasma energy e.g. electron temperature would increase by the effect of inverse bremsstrahlung (IB) absorption, when a laser beam passed through the plasma. However, in this paper, we found an interesting laser cooling arc plasma effect (LCAPE) during kilo-Watt fiber laser-TIG hybrid welding. Based on theoretical modelling and experiments, we observed that a temperature decrease of more than 5000 K at the tail of the argon plasma occurred under different process parameters during hybrid welding of 316L stainless steel. We proposed the LCAPE is caused by the laser-induced metal vapor. The mechanism mainly includes the convection cooling and enhanced radiation of the arc plasma by the metal vapor. Our findings could broaden the theory of laser-plasma interaction and provide a theoretical reference to the modulation and control of plasma in industries.
关键词： Cooling effect,Stainless steel,Laser-arc hybrid welding,Arc plasma,Fiber laser
更新于2025-11-28 14:24:20
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Filler metal distribution and processing stability in laser-arc hybrid welding of thick HSLA steel
摘要： Welds made by high power laser beam have deep and narrow geometry. Addition of filler wire by the arc source, forming the laser-arc hybrid welding (LAHW) process, is very important to obtain required mechanical properties. Distribution of molten wire throughout the entire weld depth is of concern since it tends to have low transportation ability to the root. Accurate identification of filler metal distribution is very challenging. Metal-cored wires can provide high density of non-metallic inclusions (NMIs) which are important for acicular ferrite nucleation. Accurate filler distribution can be recognized based on statistical characterization of NMIs in the weld. In the present study, it was found that the amount of filler metal decreased linearly towards the root. The filler metal tends to accumulate in the upper part of the weld and has a steep decrease at 45–55 % depth which also has wavy pattern based on longitudinal cuts. Substantial hardness variation in longitudinal direction was observed, where in the root values can reach > 300 HV. Excessive porosity was generated at 75 % depth due to unstable and turbulent melt flow based on morphology of prior austenite grains. The delicate balance of process parameters is important factor for both process stability and filler metal distribution.
关键词： Filler metal distribution,Microstructure,Thick steel,Non-metallic inclusions,High strength steel,Mechanical properties,Laser-arc hybrid welding
更新于2025-09-23 15:19:57
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A pathway to mitigate macrosegregation of laser-arc hybrid Al-Si welds through beam oscillation
摘要： Macrosegregation is rather serious during laser-arc hybrid welding (LAHW) due to poor arc penetration ability. Here we presented a simple and effective method to improve solute transfer and mitigate macrosegregation by using beam oscillation. When oscillating amplitude A ≥0.8 mm and frequency f ≥ 300 Hz, the macrosegregation of the overall weld cross-section was 300% lower than that of the non-oscillation weld, and the longitudinal section reduced by 220%. The reduction of macrosegregation was attributed to the stirring and vortex suction effect produced by high-frequency oscillating beam, which improved turbulent ?ow and the convection of molten pool to homogenize the alloying elements of hybrid weld.
关键词： Solute transfer,Element distribution,Laser-arc hybrid welding,Beam oscillation,Macrosegregation
更新于2025-09-23 15:19:57
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Influences of synergy effect between laser and arc on laser-arc hybrid welding of aluminum alloys
摘要： Researchers generally believe that synergy effect between laser and arc enables laser-arc hybrid welding to acquire obvious advantages of efficiency and quality in welding aluminum alloys. However, influences of physical essence of the synergy effect on welding process were not clear. In this study, basic principle of the synergy effect and its influences on welding process were obtained by spectral analysis of hybrid plasma plume and high-speed photographic analysis of welding process. First, the principle of the synergy effect is that laser interacts with arc to render electron energy level to transition. This process emits more photons, which enhance the heat input to the weld materials. The synergy effect is quantified by spectral intensity. It increases with the laser power, and decreases with the arc current and laser-arc distance. It is proportional to the cross section of weld, especially the upper, and beneficial to improve the welding energy utilization. Secondly, the amount of spatter in laser-arc hybrid welding is significantly less than that of arc welding. The bigger weld pool, the downward melt flow, and the reduced droplet transfer force generated by the synergy effect make the transferring droplets more easily absorbed by the weld pool, which stabilizes the transfer process and reduces the generation of spatter. The research results are beneficial for understanding hybrid welding mechanism and optimizing the welding process.
关键词： Synergy effect,Laser-arc hybrid welding,Welding penetration,Welding energy utilization,Spatter
更新于2025-09-12 10:27:22
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Weldability of TWIP and DP steel dissimilar joint by laser arc hybrid welding with austenitic filler
摘要： In this paper, an innovative 18% Mn austenitic TWIP steel, which exhibits a very good combination of strength and ductility, was joined by laser arc hybrid welding to a conventional DP steel, which consists of ferrite and martensite obtained by an inter-critical heat treatment and fast cooling. An austenitic filler wire was used to improve the weld strength by avoiding the formation of Mn segregations and improper microstructures in the fusion zone by Mn dilution. Metallographic examinations, microhardness and tensile tests were carried out to assess the effects of the laser and materials interaction on the weldability of TWIP-DP dissimilar welds. Hybrid welding and austenitic filler can have a positive effect on the weldability of the DP-TWIP dissimilar joint.
关键词： DP Steel,TWIP Steel,Dissimilar Weld,Laser Arc Hybrid Welding,Austenitic Filler
更新于2025-09-12 10:27:22
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Influence of welding angle on the weld morphology and porosity in laser-arc hybrid welding of AA2219 aluminum alloy
摘要： The influence of welding angle on weld morphologies and porosity characteristics was studied in laser-arc hybrid welding of AA2219 aluminum (Al) alloy. The upward sloping and vertical weld (USVW) was performed better than the downward sloping and vertical weld (DSVW). The high-speed camera was used to observe the welding process. It is found that the welding process becomes stable when the transitional position of the droplet was 2 mm away from the keyhole. By analyzing the force act on keyhole and characteristics of the pool, it is found that the weld morphologies and porosity characteristics were associated with gravity-laser angle (β), which affects the keyhole stability and characteristics of the pool. The results showed that the flow velocity was accelerated when the β increased, which was a benefit for decreasing porosity. This is because the gravity in the direction of the welding accelerates the pool flow. Due to the increasing of the β, the static pressure and the vapor pressure in the keyhole were increased, which improved the stability of the keyhole and decreased the porosity.
关键词： Keyhole,Weld morphology,Porosity,Aluminum alloy,Laser-arc hybrid welding
更新于2025-09-12 10:27:22
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High-nitrogen steel laser-arc hybrid welding in vibration condition
摘要： Welding porosity and nitrogen content are considered significant factors affecting the mechanical properties of fusion-welding joints of high-nitrogen steel. In this study, a method of applying mechanical vibration in the welding process to reduce weld porosity and increase weld nitrogen content was investigated. The effects of mechanical vibration on porosity, tensile, and impact properties were analysed. The results indicated that the bubble floating speed in the vibrating weld pool is faster than that in the general welding mode. With the increase of mechanical vibration frequency, the porosity of the weld decreased at first and then rose. The tensile strength and impact energy increased first and then decreased, and the fracture surface indicated a ductile fracture.
关键词： nitrogen content,vibration,porosity,austenitic stainless steel,high-nitrogen steel,Laser-arc hybrid welding,microstructure,mechanical properties
更新于2025-09-12 10:27:22
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Аpplication Development for the Evaluation of Penetration in Laser and Laser-Arc Hybrid Welding of Tee and Corner Joints
摘要： Laser technologies deservedly take their place in modern mechanical engineering production. Using laser source for welding has already become common. However, the creation of critical welded constructions is impossible without extensive technological surveys, which can be greatly simplified by using a computational experiment. To achieve this goal, special programs are usually used. That can be unjustified difficult and thereby awkward for technological practice. The article describes an application built on the basis of a simplified model for calculating the temperature field for the cases of laser and laser-arc welding of internal fillet welds as well as single-sided T-joints and simultaneous double-sided welds. The results of calculations by the model and comparing them with experimental data have shown that it is sufficiently adequate for use in technological purposes. The developed application contemporaneously has a simple and intuitive interface, does not require significant computational resources and can be used for quick preliminary estimation of the result of welding for the selected type of weld.
关键词： T-joint welding,laser-arc hybrid welding,Laser welding,software,Corner joint welding
更新于2025-09-11 14:15:04