Hybrid laser-arc welding is a new welding process which has received particular attention in various industries because of its technological and economic advantages. This process combines a laser beam and an electric arc to incorporate the advantages of both laser and arc welding processes. The main goal of this paper is to evaluate the performance and ability of hybrid Nd: YAG laser-TIG welding compared to lone laser welding process for welding of aluminum foam sandwich (AFS) panels of AA6082. To this aim, a set of experiments for both laser and hybrid laser-TIG welding were done to investigate the effects of welding parameters including laser power, arc current and welding speed on weld dimensions.Then, appropriate welding parameters for the laser and hybrid laser-TIG welding of AFS panels were calculated by statistical analysis. The results show that laser power threshold for creating the keyhole was less in hybrid laser-TIG welding than lone laser welding. Moreover, increasing the laser power and decreasing the welding speed result in increasing both the weld depth and width. But, with increasing the arc current, the weld depth remains almost unchanged and only the weld width increases.Comparing the laser and hybrid laser-TIG results show that adding a 100 A arc to a 2000 W laser source can increase the welding speed from 2 to 3 m/min which proves the high ability and efficiency of hybrid laser-TIG welding process.

Polymethyl methacrylate (PMMA) is extensively used in automotive, aerospace, and consumer products industries due to its favorable mechanical characteristics. Laser Transmission Welding (LTW) has recently gained attention as an advanced joining method for creating strong, narrow, and lightweight welds in thermoplastics like PMMA. This study examines the effects of three key process parameters—laser power, welding speed, and scan line spacing—on the LTW performance when bonding two transparent PMMA sheets using a fiber laser along a zigzag path. The main objective is determining the feasibility of practical welding at low laser power while achieving high joint strength. Experimental design and optimization were conducted using Analysis of Variance (ANOVA) and Response Surface Methodology (RSM). ANOVA confirmed that all three parameters significantly influenced lap-shear force. RSM results showed that higher laser power, lower welding speed, and reduced scan line spacing increased heat input and improved weld strength, with a maximum lap-shear force of 1256 N. In contrast, lower laser power, faster welding, and wider spacing reduced heat input and resulted in a minimum strength of 245 N. Desirability-based optimization identified optimal settings of 30 W laser power, 400 mm/s welding speed, and 0. 015 mm scan line spacing, predicting a lap-shear force of 1249. 2 N with 99. 3% confidence. The results demonstrate that zigzag LTW of PMMA is feasible at low power levels, attributed to uniform heat distribution and consistent melting achieved by the zigzag path.

Inconel 718 is used in a wide range of industries such as oil and gas, nuclear, aviation, and etc. due to its excellent mechanical properties. The use of additive manufacturing (AM) to manufacture parts is increasing rapidly Due to the dimensional limitations in the manufacturing of parts using the additive manufacturing methods, these parts must be connected to other parts in different applications with the help of conventional methods such as welding. In this research, the thermal analysis of plasma welding of an Inconel 718 sheet made by SLM method using ABAQUS software is discussed. Input heat with Gaussian distribution was entered into the model by DFLUX subprogram with FORTRAN program language. In order to validate the thermal model, the temperature was measured during the welding process using a thermocouple. A relatively good match is observed between the numerical and experimental thermal analysis results. The microstructure of the welded samples was examined with an optical microscope and the microstructure of base metal, fusion zone, and heat affected zone were investigated. The dendritic structure in the welding area and the occurrence of recrystallization in the heat-affected area was evident. The tensile test results showed that the sample without welding has a higher yield and ductility.

In this paper, laser beam welding of a rectangular piece of steel was simulated using Fluent software. Physical properties of analytical field was constant and its changes with temperature was ignored. In the present work, effect of tool speed and laser power on temperature distribution of workpiece surface and different deeps in the plane of symmetry and also maximum of temperature and depth of penetration were investigated. Using a macro code, geometry generation and meshing of the analytical field by helping required geometric parameters were provided for software. Moreover, laser radiation power was exerted by writing an UDF in the fluent software. In this case, it was assumed that the workpiece is stationary and gaussian thermal source model defined in UDF moves with the intended speed. Results show that at a constant power, maximum temperature of the workpiece decreases with increasing heat source speed, moreover, in this case, gradient of temperature in front of the workpiece and behind of it, increases and decreases respectively. It is found that the temperature in the depth of the workpiece increases with increasing the power.

The laser welding of magnesium alloys, largely used in many fabrication applications, has gained considerable interest especially in aerospace, electronics, automotive industry etc. Unfortunately, this process is associated to an undesired phenomenon which is “ oxidation” . For this reason, a good shielding system of the welding zone is of major importance. This paper presents a numerical study using computational fluid dynamics (CFD) of a laser welding process employing a moving volumetric heat source. Starting with the turbulence model validity, a parametric study of this welding process in a vertical position aiming to optimize the design of protection gas device, the gas jet inclination, the appropriate welding direction and the gas type is, then, proposed. The optimum parametric combination ensuring the largest gas coverage area is the one where the shielding gas is Argon, supplied by the coaxial nozzles at a downward inclination angle with respect to the laser beam axis, and a downward welding direction.

Considering possible plastic deformations for metals such as steel during design calculations reduces metal consumption in practice. In general, structural elements with heavy loads, such as shells of building structures, rockets, chemical reactors, thin-walled pipes and other structures, are designed using computational methods, in order to properly and scientifically design, plastic deformations should be considered in them. Laser welding is one of the most important and sensitive types of welding in metals, which has many applications in various industries. In the present study, the effects of laser processing on the mechanical strength of steel sheets and their resistance to bending loads caused by laser radiation have been investigated. The results of bending tests and computer simulation of elastoplastic deformation show that st37 carbon steel sheet subjected to local laser processing with surface melting due to increased mechanical strength can be used as a suitable replacement for more resistant and expensive alloys in advanced industrial and military applications.

Overlapped strips of titanium grade 2 and aluminum 3105-O alloy were welded together under an innovative spot-like pulse laser procedure. The tactile seam tracking on ring paths yielded reliable weld  t-up of 1 and 0. 5 mm thickness strips. Since the welding parameters of Ti-Al were narrow, three welding speeds of 4, 5, and 6. 67 mm. s-1 were chosen for the pretest conditions. The microstructural investigations showed that intermetallic compound Ti3Al formed in the Ti-rich fusion zone. Cracks formed in the Al-rich fusion zone as a result of TiAl3 precipitation. Dimple fracture occurred at 6. 67 mm. s-1 welding speed. Longer mixing time at Ti-Al interface occurred at lower welding speeds of 4 and 5 mm. s-1, which led to the formation of thicker intermetallic compounds and more massive crack generation. It also increased the hardness of the fusion zone and resulted in brittle fracture type during the tensile test. The highest strength was achieved with a welding speed of 4 mm. s-1, which was a result of more massive weld nugget and lower porosity.

Although in recent years, welding of polymers has been developed but welding of polycarbonates is still faced with serious challenges such as improving the quality of welded section. In the present study, mechanical properties of polycarbonate friction stir welded samples with different nano alumina content were investigated. For this purpose, firstly polycarbonate (as matrix) was melt compounded with nano alumina in variant weight percentages including 0, 1, 2 and 3% using a twin-screw extruder. Then, nanocomposite samples were produced using an injection molding machine and were friction stir welded with a special tool on a milling machine. The effects of weight percentage of nano alumina, travel and rotational speeds (all in four levels) were investigated on the tensile strength and hardness of the welded nanocomposite samples according to a L16 orthogonal array of Taguchi method. According to the obtained results, the weight percentage of nano alumina is the most effective parameter on the tensile strength and hardness of welded nanocomposite specimens. By increasing the percentage of nano alumina to 1%, tensile strength increased. However, by increasing the nano alumina more than 1%, this strength reduced due to agglomeration of nanoalumina in high weight percentages. Results also demonstrated that processing parameters do not affect the mechanical properties of welded nanocomposite samples significantly.

Laser welding is a novel method for direct joining of metals and polymers, which leads to a mechanical and chemical bond between metal and polymer. In this study, feasibility of dissimilar joining between St12 and polycarbonate is studied theoretically. Then, the ND: YAG laser is implemented to join St12 and Polycarbonate. Empirical results indicate creation of a joint between St12 and polycarbonate. In order to conduct thermomechanical analysis of the welding process, the finite element model has been developed by Abaqus software. In addition, the cylindricalinvolution-normal (CIN) heat source model was used to describe the laser power distribution and FORTRAN software has been used to define the thermal model in welding simulation. Comparison of experimental and simulation results shows that the finite element model is capable of predicting weld width, and therefore the results of the finite element model are verified. Therefore, the finite element model is used to predict residual stresses. The results disclose that dissimilar bonding creates residual tension stresses on the metal surface and compressive residual stresses on the polymer surface.