Laser Welding Research Articles

Effect of CO2 Laser Beam Welding on Microstructure and Tensile Strength of C250 Maraging Steel

Effect of CO2 Laser Beam Welding on Microstructure and Tensile Strength of C250 Maraging Steel

Integrated vision-based seam tracking system for robotic laser welding of curved closed square butt joints

Integrated vision-based seam tracking system for robotic laser welding of curved closed square butt joints

Effect of Filler-Wire Composition on Microstructure and Properties of Al/Steel-Welded Joints by Laser Welding–Brazing

Effect of Filler-Wire Composition on Microstructure and Properties of Al/Steel-Welded Joints by Laser Welding–Brazing

The calculation of keyhole depth based on the primary absorption of front keyhole wall in laser deep-penetration welding

The establishment of an accurate prediction model of keyhole depth during laser welding is of great significance for predicting the weld depth or pre-selecting suitable welding process parameters. In this paper, based on the primary absorption of the incident laser by the front keyhole wall, the tilt angle of the keyhole wall was calculated point by point according to the equilibrium relationship between the laser energy absorbed by the material and the energy required for evaporation at any position of the front keyhole wall. A prediction model for the keyhole depth in laser deep penetration welding has been established by taking into account the laser optical parameters, the focusing system parameters, the welding process parameters, and the material properties. The transformation law of the front keyhole wall profile, the Fresnel absorption coefficient, and the keyhole depth with laser power, welding speed, focusing focal length, and other parameters was calculated in the model, which is basically in line with the consensus. At the same time, the keyhole depth results of calculations and measurements under some parameter conditions were compared. It can be found that the prediction model of keyhole depth during laser deep penetration welding can be used to approximate the calculation of weld depth, and the feasibility of the model was preliminarily verified. Moreover, combined with previous experimental results, the conclusion that the primary absorption of front keyhole wall is the key factor determining the keyhole depth can be re-verified by using mathematical calculations. It also shows that the complex energy coupling law in keyhole has a noticeable difference in the influence of different physical phenomena during laser deep penetration welding.

Effect of rotating laser welding on microstructure and mechanical properties of Ti6Al4V alloy butt-welded joint

Effect of rotating laser welding on microstructure and mechanical properties of Ti6Al4V alloy butt-welded joint

Characterization of particles inside the metal vapor plume during laser beam welding in atmosphere and vacuum

Characterization of particles inside the metal vapor plume during laser beam welding in atmosphere and vacuum

Toward prediction and insight of porosity formation in laser welding: A physics-informed deep learning framework

Toward prediction and insight of porosity formation in laser welding: A physics-informed deep learning framework

Enhancement of weld penetrations classification model performance through the implementation of denoising methods towards the acquired acoustic and optical signals during laser beam welding process

Enhancement of weld penetrations classification model performance through the implementation of denoising methods towards the acquired acoustic and optical signals during laser beam welding process

Achieving deep penetration welding of 100 mm level thick titanium alloy using vacuum laser beam welding

Achieving deep penetration welding of 100 mm level thick titanium alloy using vacuum laser beam welding

Study on dynamic behavior of laser welding plume by in-situ tracking particle. Part C: Depth monitoring

Study on dynamic behavior of laser welding plume by in-situ tracking particle. Part C: Depth monitoring

Machine learning-assisted design of filler for laser welding of Al-Zn-Mg-Cu alloy

Machine learning-assisted design of filler for laser welding of Al-Zn-Mg-Cu alloy

The effect of Gd content on the microstructure and mechanical properties of AM50 magnesium alloy in pulsed laser welding

The effect of Gd content on the microstructure and mechanical properties of AM50 magnesium alloy in pulsed laser welding

Study on the Influence of Laser Welding Residual Stress on the Fatigue Strength of a TC4 Thin Sheet Butt Joint

In order to further study the effect of welding residual stress on the fatigue strength of a TC4 titanium alloy sheet during laser welding, a laser welding butt joint model for TC4 titanium alloy sheets was established using ABAQUS (2022) software. The temperature and residual stress fields generated during the welding process were comprehensively simulated, and the melt pool shape and residual stress magnitudes were experimentally verified. The experimental parameters included a laser power range of 900–1200 W, welding speeds of 12.5 and 25 mm/s, and a double-sided welding approach with a cooling interval of 20 s between passes. The findings indicate that welding residual stress is primarily concentrated around the weld and the heat-affected zone, predominantly as tensile stress, with the maximum value observed at the weld’s initiation point, reaching 920 MPa—close to the material’s tensile strength limit. Under ideal conditions (without considering welding residual stress), the fatigue life at the weld area is estimated to reach 188,799 cycles, while the fatigue life of the base material without welding is calculated to be 167,109 cycles. However, when accounting for welding residual stress, the fatigue strength of the sheet decreases significantly, with the minimum fatigue life occurring at the weld toe, measured at 10,471 cycles. This study demonstrates that welding residual stress has a substantial impact on the fatigue life of TC4 titanium alloy sheets, particularly in the heat-affected zone, where the fatigue life is reduced by nearly 94% compared to the ideal condition. These results provide critical insights for improving the fatigue performance of laser-welded TC4 titanium alloy components in engineering applications.

An energy-saving optimization method for robot laser welding systems based on multi-objective metaheuristic algorithms

An energy-saving optimization method for robot laser welding systems based on multi-objective metaheuristic algorithms

Avoiding the formation of pores during laser welding of copper hairpins by dynamic beam shaping

Abstract Any pores formed during laser welding of copper hairpins affect the structural integrity and the mechanical/electrical functionality of the joint. We report on investigations using synchrotron X-ray imaging techniques to observe the formation of the pores in the processing zone while welding. It was found that all pores are formed at the joint gap and that the small pores are distributed throughout the complete joint volume as a result of the melt flow induced by the movement of the laser beam. This insight has led to the development of a welding strategy that minimizes pore formation by avoiding the movement of the laser beam across the joint gap. This was achieved by rapid beam shaping based on coherent beam combining (CBC) technology.

Investigation of Design Potentials for Welding PBF-LB/M Manufactured Pure Copper Busbars to Conventional Copper Conductors

The advantages of the laser beam powder bed fusion process for metals (PBF-LB/M), such as geometric complexity due to increased design freedom or function integration, offer a great potential for optimizing products in the automotive sector. However, it often does not go beyond prototyping and small series as productivity is too low for the required quantities and economies of scale can rarely be exploited lucratively. In the field of e‑mobility, hairpin technology has recently come to dominate the copper winding of traction drives. The research field of additive manufacturing (AM) of copper windings for e‑machines has made significant progress in recent years, but additive manufacturing has not yet prevailed over conventional technologies, despite the product advantages.In this study the approach of transferring the complexity of conventional hairpin windings into additively manufactured busbar assemblies and then joining them to conventional windings using laser welding is investigated. The advantage is that the less complex components of an electric machine can still be manufactured conventionally with high productivity.For this purpose, different design variants of the connection geometry are developed at the interconnection area of the busbars and manufactured from copper using PBF-LB/M. The manufactured design variants are then joined to the conventional copper conductors using a laser welding process. A comprehensive analysis and evaluation of the connections is then carried out in four main categories. The design, the electrical conductivity, the critical heating und real boundary conditions as well as and the weldability are examined. Three designs with promising results and requirement fulfilling properties were identified. The results show that functions like form fitting can directly be added to the AM parts and by the complexity transfer, both advantages of additive manufacturing and conventional manufacturing can be combined by means of laser welding.

Optimization of laser welding process parameters considering carbon emissions and weld quality based on DBO-BP and NSGA-II

Optimization of laser welding process parameters considering carbon emissions and weld quality based on DBO-BP and NSGA-II

EFFECTS OF OPTIMIZATION PARAMETERS ON FIBER LASER WELDING OF SMA490AW WEATHERING STEEL USING RESPONSE SURFACE METHODOLOGY

In fiber laser welding experiments with the SMA490AW weathering steel, 3-mm steel plates were laser welded in a butt joint using an ytterbium fiber laser. The experiment was conducted using a central composite design (CCD). The parameters for the laser fiber settings were: laser power: 1,800 W to 2,000 W, welding speed: 10 mm/s to 12 mm/s, focus position: -1.5 mm to 0.0 mm. The results were analyzed using analysis of variance (ANOVA) for penetration depth, ultimate tensile strength (UTS), and elongation (%EL). Key findings: penetration depth was affected by focus position, power, and speed. Maximum penetration depth was achieved with the following settings: focus position -1.5 mm, power 2,000 W, speed 10 mm/s. Ultimate Tensile Strength (UTS) was affected by power, speed, focus position, quadratic term of power (power²), and interaction terms of power* speed and power* focus position. Maximum UTS was achieved with the following settings: power 2,000 W, speed 12 mm/s, focus position -1.5 mm. Elongation (%EL) was affected by speed, focus position, and interaction term of speed*focus position. Maximum %EL was achieved with the following settings: speed 12 mm/s, focus position -1.5 mm. Optimum fiber laser welding conditions for SMA490AW included power: 2,000 W, speed: 12 mm/s, and focus position: -1.5 mm.

Magnetic modulation of keyhole instability during laser welding and additive manufacturing.

Keyhole instability during laser welding and laser powder bed fusion (LPBF) can cause keyhole collapse and pore formation. Using high-speed x-ray imaging, we demonstrate that the flow vortex-induced protrusion on the rear keyhole wall is crucial in initiating keyhole instability. Applying a transverse magnetic field suppresses the keyhole instability by driving a secondary thermoelectric magnetohydrodynamics (TEMHD) flow that alters the net flow vortex. This minimizes protrusions and large-amplitude keyhole oscillations. The suppression effectiveness depends on the laser scanning direction relative to the magnetic field orientation because this controls the Seebeck effect-induced Lorentz force's direction. We show that at LPBF length scales, electromagnetic damping is weak, and for alloys with a large Seebeck coefficient, TEMHD becomes the dominant mechanism controlling flow behind the keyhole.

A method of profile control applied in laser technology

The proposed model allows the generation of any two-dimensional profile, which can be applied, for example, in laser welding and cutting techniques. In the paper, a system model for generating two-dimensional profiles using two galvanometer mirrors placed on two perpendicular axes is studied and designed. The forward and inverse kinematic equations establishing the relationship between the mirror motion and the laser profile are proposed and thoroughly solved by the author, and the author also presents the control problem to generate the desired profile. Simulations on Matlab are performed for circular and figure-8 profiles. The simulation results obtained profiles similar to the desired profile, both in shape and scanning frequency.