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Evaluation criterion and closed-loop control of penetration status during laser-MIG hybrid welding J. Laser Appl. 22, 92 (2010); 10.2351/1.3492616 Studies on characteristics of CO 2 laser-GTAW hybrid welding of austenitic stainless steel J. Laser Appl. 22, 79 (2010); 10.2351/1.3455995The effect of shielding gas composition on welding performance and weld properties in hybrid CO 2 laser-gas metal arc welding of carbon manganese steel Hybrid processes have been established for the joining of thick plates. The presented approach enables single side welding of thick metal plates by combining a laser beam and two gas metal arc (GMA) welding torches in one setup. By using this hybrid process for joining high material thicknesses, manufacturing time can be significantly reduced in comparison to conventional multilayer arc welding processes. Additionally, new joint designs can be used to reduce filler metal consumption. In order to benefit from these economic advantages, and to make use of brilliant high power lasers in pipeline manufacturing, this hybrid process needs to run robustly for common gap and tolerance ranges. The process time, compared to conventional methods, will be significantly decreased, due to the use of disk lasers with a maximum output power of 16 kW combined with two high power GMA subprocesses. For process development, American Petroleum Institute (API) 5L X70 pipeline steel plates with a thickness of 23 mm have already been joined in a flat position using a single weld pass. Based on these parameter studies, the process limitations have been determined with regard to energy input, gap bridgeability, vertical edge offset, and a lateral offset of the energy sources from the weld joint. The robustness of the hybrid process developed has been demonstrated in experiments representative of the pipeline application. V C 2014 Laser Institute of America.

The industrial use of GMA-laser hybrid welding has increased in the last 10 years, due to the brilliant quality of the laser beam radiation, and higher laser output powers. GMA-laser hybrid welding processes operate in a common molten pool. The combination of the laser beam and the arc results in improved welding speed, penetration depth, heat affected zone and gap bridgeability. Single-layer, GMA-laser hybrid welding processes have been developed for high-strength fine-grain structural steels with a grade of S690QL and a thickness of 15 mm and 20 mm. In addition, the welding process is assisted by an integrated, inductive preheating process to improve the mechanical properties of the welding seam. By using the determined parameters regarding the energy per unit length, and the preheating temperature, welding seams with high quality can be achieved.

For lightweight construction, different steel and aluminum materials with various thicknesses can be welded together, depending on the dimensions and the individual functions of the workpiece. Specifically for frame and body construction, remote laser beam welding has been established as a suitable and efficient joining method for similar material seams for several years. In contrast to joining similar materials, thermal joining of steel and aluminum alloys includes different technological challenges due to the formation of hard and brittle intermetallic phases, which decreases the strength and the formability of the dissimilar joints. In the context of these requirements, the presented results show, besides the influence of different steel materials, particularly the influence of different sheet thicknesses and thickness ratios on the appropriate process parameters for remote laser beam welded lap joints of steel and aluminum alloys, respectively. Different thickness ratios, process parameters, and material properties affect the geometrical formation of the weld seam regarding penetration depth tE and weld width b, which mainly influences the composition of the molten bath and accordingly the transmittable forces. Within the scope of the presented investigations, dissimilar joints of the steel materials such as HX220LAD+Z100, 22MnB5+AS150, and 1.4301 as well as the aluminum alloy such as AA6016-T4 are characterized. Among others, the influences of the energy per unit length, material grade, and sheet thickness ratio on the achievable strengths were analyzed. The characterization of the dissimilar joints includes tensile shear tests and metallographic analyses, depending on the energy per unit length.

Nowadays, there is a strong and growing ambition to switch from combustion technology to battery-electric drives, and energy storage is spotlighted. Laser beam welding is an appropriate and favorable welding technology in battery production. Due to the high welding speed, the local heat input, the contact freeness efficient, and automatable processes can be established. Materials used in batteries for electrodes that have to be connected are commonly copper and aluminum. Specifically, copper is highly reflective for widely used infrared laser beam wavelengths. Furthermore, the thickness in the area of 10  μm is quite challenging to deal with, in terms of gap free clamping and avoidance of damage to the material as well as distortion during welding. There is a fine line regarding energy input between burning the material and generating a lack of fusion. In the presented research, welding approaches with different laser beam sources emitting laser beams with infrared wavelengths, various beam shapes, and welding modes (continuous and pulsed) are studied. A total of 40 copper foils with a thickness of 10  μm and 40 aluminum foils with a thickness of 15  μm are welded to similar sheet metals. Aim of the process development are welds with high quality and high connection widths to provide the best electric conductivity.