Laser Beam and Laser-Arc Hybrid Welding of Aluminium Alloys

Bunaziv, Ivan; Akselsen, Odd M.; Ren, Xiaobo; Nyhus, Bård; Eriksson, Magnus

doi:10.3390/met11081150

Cited by 34 publications

(30 citation statements)

References 312 publications

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“…Materials' Properties: Since the proposed model considers the solid-liquid phase change, the properties at ambient temperature for the solid phase and at melting temperature for the liquid phase were used. Specific heat, thermal conductivity coefficient [18,22], and density [11,19] were then defined (Table 4). The absorption value was chosen for aluminum 0.16 [20,21].…”

Section: Numerical Modeling: Finite Element Methodsmentioning

confidence: 99%

Emissivity Prediction for an IR Camera During Laser Welding of Aluminum

Metallo

2022

International Journal of Thermodynamics

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Laser processing is becoming increasingly important in industrial applications. The success of the process relies on two fundamental parameters: the surface temperature of the medium and the thickness of the hardened layer. One of the most important factors during a laser process is certainly the temperature, which presents high temperature gradients. The speed at which a material undergoes a phase transition, the chemical reactions that take place during processing and the properties of the material are all dependent on temperature changes. Consequently, the measure of temperature is a demanding undertaking. This study proposes to measure temperature for the duration of laser welding with the infrared camera (IR) Optris PI. To restore the real temperature based on the brightness temperature values measured by the IR camera is needed to evaluate the emissivity to be attributed to the IR camera. For this purpose, firstly, the isotherms consistent with the melting point of aluminum (785 K) were assessed and then compared with the temperature distribution gauged in the zone of irradiation of the laser. Such data were then compared with the thickness of the melted zone. The use of the melting point isotherm allowed the calculation of the value of emissivity and the restoration of the temperature. Thermography software data acquisition wrongly presupposes the emissivity value does not change. This generates incorrect thermographic data. The surface emissivity normally hinges on temperature. Therefore, the values on which the literature relies may not work for materials of interest in the conditions of the process. This is particularly the case, where welding is carried out in keyhole mode (Tmax = Tvap). However, the physical phenomena involved, including evaporation and plasma plume formation, high spatial and temporal temperature gradients, and non-equilibrium phase transformations, influence the optical conditions of the brightness of the emission of light from the molten pool, making, De Facto, the emissivity value not constant. Thus, what we propose here is a methodological procedure that allows the measurement of the effective emissivity of the surface, at the same time taking into consideration the consequence of physical phenomena and the conditions of the surface. Two procedures (Standard and Simplified) capable of providing the correct emissivity value in relation to the working parameters have been proposed. The results showed that the procedures are correct, fast, and easy to use.

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Section: Numerical Modeling: Finite Element Methodsmentioning

confidence: 99%

Emissivity Prediction for an IR Camera During Laser Welding of Aluminum

Metallo

2022

International Journal of Thermodynamics

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“…As shown in Fig. 2, two different operational regimes of LBW process including heat-conduction type and keyhole type exist governed by the laser power density [24]. During the conduction welding process, the focused laser beam spot heats up the material to its melting temperature and then quickly creates a stable melt pool on the surface of metal, but the laser power density is not large enough to create boiling metal pool (see Fig.…”

Section: Fundamentals Of Lbw and Process Monitoring 21 Physical Chara...mentioning

confidence: 99%

“…3. Schematic illustration (a) of laser beam keyhole welding during full-penetration [24] and (b) examples of common welding defects.…”

Section: Categories Of Laser Welding Defectsmentioning

confidence: 99%

Progress and perspectives of in-situ optical monitoring in laser beam welding: Sensing, characterization and modeling

Zhang

et al. 2022

Journal of Manufacturing Processes

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“…The keyhole mode often has a spiking effect, as the keyhole collapses, causing porosity. Therefore, more optimisation of parameters is needed, but it is more attractive for thicker plates [25,26].…”

Section: Fundamentals Of Laser Beam Weldingmentioning

confidence: 99%

A Review on Laser-Assisted Joining of Aluminium Alloys to Other Metals

Bunaziv

Akselsen

Ren

et al. 2021

Metals

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Modern industry requires different advanced metallic alloys with specific properties since conventional steels cannot cover all requirements. Aluminium alloys are becoming more popular, due to their low weight, high corrosion resistance, and relatively high strength. They possess respectable electrical conductivity, and their application extends to the energy sector. There is a high demand in joining aluminium alloys with other metals, such as steels, copper, and titanium. The joining of two or more metals is challenging, due to formation of the intermetallic compound (IMC) layer with excessive brittleness. High differences in the thermophysical properties cause distortions, cracking, improper dilution, and numerous weld imperfections, having an adverse effect on strength. Laser beam as a high concentration energy source is an alternative welding method for highly conductive metals, with significant improvement in productivity, compared to conventional joining processes. It may provide lower heat input and reduce the thickness of the IMC layer. The laser beam can be combined with arc-forming hybrid processes for wider control over thermal cycle. Apart from the IMC layer thickness, there are many other factors that have a strong effect on the weld integrity; their optimisation and innovation is a key to successfully delivering high-quality joints.

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Laser Beam and Laser-Arc Hybrid Welding of Aluminium Alloys

Cited by 34 publications

References 312 publications

Emissivity Prediction for an IR Camera During Laser Welding of Aluminum

Emissivity Prediction for an IR Camera During Laser Welding of Aluminum

Progress and perspectives of in-situ optical monitoring in laser beam welding: Sensing, characterization and modeling

A Review on Laser-Assisted Joining of Aluminium Alloys to Other Metals

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