Laser Beam Welding With Simultaneous Gaussian Laser Preheating

1993 ◽  
Vol 115 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Y.-N. Liu ◽  
E. Kannatey-Asibu
Keyword(s):  
Heat Source ◽  
Laser Beam ◽  
Cooling Rate ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Input Power ◽  
Relative Power ◽  
Gaussian Source ◽  
Distribution Parameters ◽  
Dual Laser

An analytical solution of the dual, laser beam welding process is presented. It is based on a Gaussian distributed leading heat source for preheating, followed by a line source for the actual welding process. The effect of beam distribution parameters as well as interbeam spacing and relative power intensities on the resulting temperature distribution and cooling rate are presented. For a preheating Gaussian source of power 1550 W, the depth of region above 500°C is 2.25 mm, and that above 250°C is 3.5 mm. The cooling rate at the weld centerline without preheating for a temperature of 650° C, input power 1800 W, and welding velocity 20 mm/s is found to be 1004°C/s. Under the same conditions, the cooling rate with a 1550 W preheating Gaussian distributed heat source (beam distribution parameter 1 mm, and interbeam spacing 10 mm) is reduced to 570°C/s.

Numerical Simulation on Temperature Field in Multi-Layers Inside-Beam Powder Feeding when Laser Cladding

2012 ◽  
Vol 499 ◽  
pp. 114-119 ◽  
Author(s):  
Ming Di Wang ◽  
Shi Hong Shi ◽  
X.B. Liu ◽  
Cheng Fa Song ◽  
Li Ning Sun
Keyword(s):  
Numerical Simulation ◽  
Heat Source ◽  
Laser Beam ◽  
Cooling Rate ◽  
Light Source ◽  
Laser Cladding ◽  
Laser Scanning ◽  
Initial Conditions ◽  
Cladding Layer ◽  
Powder Feeding

Numerical simulation of laser cladding is the main research topics for many universities and academes, but all researchers used the Gaussian laser light source. Due to using inside-beam powder feeding for laser cladding, the laser is dispersed by the cone-shaped mirror, and then be focused by the annular mirror, the laser can be assumed as the light source of uniform intensity.In this paper,the temperature of powder during landing selected as the initial conditions, and adopting the life-and-death unit method, the moving point heat source and the uniform heat source are realized. In the thickness direction, using the small melt layer stacking method, a finite element model has been established, and layer unit is acted layer by layer, then a virtual reality laser cladding manu-facturing process is simulated. Calculated results show that the surface temperature of the cladding layer depends on the laser scanning speed, powder feed rate, defocus distance. As cladding layers increases, due to the heat conduction into the base too late, bath temperature will gradually increase. The highest temperature is not at the laser beam, but at the later point of the laser beam. In the clad-ding process, the temperature cooling rate of the cladding layer in high temperature section is great, and in the low-temperature, cooling rate is relatively small. These conclusions are also similar with the normal laser cladding. Finally, some experiments validate the simulation results. The trends of simulating temperature are fit to the actual temperature, and the temperature gradient can also ex-plain the actual shape of cross-section.

scholarly journals Spectroscopic closed loop control of penetration depth in laser beam welding process

2012 ◽  
Author(s):  
Teresa Sibillano ◽  
Antonio Ancona ◽  
Domenico Rizzi ◽  
Francesco Mezzapesa ◽  
Ali Riza Konuk ◽  
...  
Keyword(s):  
Laser Beam ◽  
Penetration Depth ◽  
Closed Loop ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Closed Loop Control ◽  
Loop Control

scholarly journals Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets

2018 ◽  
Author(s):  
Iñigo Hernando ◽  
Jon Iñaki Arrizubieta ◽  
Aitzol Lamikiz ◽  
Eneko Ukar
Keyword(s):  
Numerical Model ◽  
Laser Beam ◽  
Inconel 718 ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Bead Geometry ◽  
Predictive Tool ◽  
Melt Pool ◽  
Dendritic Arm Spacing ◽  
Weld Seams

A numerical model was developed for predicting the bead geometry and microstructure in Laser Beam Welding of 2 mm thickness Inconel 718 sheets. The experiments were carried out with a 1 kW maximum power fiber laser coupled with a galvanometric scanner. Wobble strategy was employed for sweeping 1 mm wide circular areas for creating the weld seams and a specific tooling was manufactured for supplying protective Argon gas during the welding process. The numerical model takes into account both the laser beam absorption and the melt-pool fluid movement along the bead section, resulting in a weld geometry that depends on the process input parameters, such as feed rate and laser power. The microstructure of the beads was also estimated based on the cooling rate of the material. Features as bead upper and bottom final shapes, weld penetration and dendritic arm spacing were numerically and experimentally analyzed and discussed. The results given by the numerical analysis agree with the tests, making the model a robust predictive tool.

scholarly journals Hybrid laser-arc welding of laser- and plasma-cut 20-mm-thick structural steels

2022 ◽  
Author(s):  
Ömer Üstündağ ◽  
Nasim Bakir ◽  
Sergej Gook ◽  
Andrey Gumenyuk ◽  
Michael Rethmeier
Keyword(s):  
Laser Beam ◽  
Arc Welding ◽  
Laser Beam Welding ◽  
Digital Camera ◽  
Welding Process ◽  
Beam Power ◽  
Beam Diameter ◽  
Hybrid Laser Arc Welding ◽  
Single Pass ◽  
New Findings

AbstractIt is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.

scholarly journals Thermal Finite Element Modelling of the Laser Beam Welding of Tailor Welded Blanks through an Equivalent Volumetric Heat Source

2021 ◽  
Author(s):  
Vito Busto ◽  
Donato Coviello ◽  
Andrea Lombardi ◽  
Mariarosaria De Vito ◽  
Donato Sorgente
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Numerical Models ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Butt Joint ◽  
Volumetric Heat Source ◽  
Tailor Welded Blanks ◽  
Mechanical Models ◽  
Physical Phenomena

Abstract In last decades, several numerical models of the keyhole laser welding process were developed in order to simulate the joining process. Most of them are sophisticated multiphase numerical models tempting to include all the several different physical phenomena involved. However, less computationally expensive thermo-mechanical models that are capable of satisfactorily simulating the process were developed as well. Among them, a moving volumetric equivalent heat source, whose dimensions are calibrated on experimental melt pool geometries, can estimate some aspects of the process using a Finite Element Method (FEM) modelling with no need to consider fluid flows. In this work, a double-conical volumetric heat source is used to arrange a combination of two half hourglass-like shapes with different dimensions each other. This particular arrangement aims to properly assess the laser joining of a Tailor Welded Blank (TWB) even in case of butt joint between sheets of different thicknesses. Experiments of TWBs made of 22MnB5 steel sheets were conducted in both equal and different thicknesses configurations in order to validate the proposed model. The results show that the model can estimate in a satisfactory way the shape and dimensions of the fused zone in case of TWB made of sheets with different thickness.

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