Hybrid welding, using the combination of a laser and an electrical arc, is designed to overcome problems commonly encountered during either laser or arc welding such as cracking, brittle phase formation and porosity. When placed in close contact with each other, the two heat sources interact in such a way as to produce a single high intensity energy source. This synergistic interaction of the two heat sources has been shown to alleviate problems commonly encountered in each individual welding process. Hybrid welding allows increased gap tolerances, as compared to laser welding, while retaining the high weld speed and penetration necessary for the efficient welding of thicker workpieces. A number of simultaneously occurring physical processes have been identified as contributing to these unique properties obtained during hybrid welding. However, the physical understanding of these interactions is still evolving. This review critically analyses the recent advances in the fundamental understa...

Problems and issues in laser-arc hybrid welding

Welding of AZ31B magnesium alloy was carried out using hybrid laser–TIG (LATIG) welding, laser beam welding (LBW) and gas tungsten arc (TIG) welding. The weldability and microstructure of magnesium AZ31B alloy welded using LATIG, LBW and TIG were investigated by OM and EMPA. The experimental results showed that the welding speed of LATIG was higher than that of TIG, which was caught up with LBW. Besides, the penetration of LATIG doubles that of TIG, and was four times that of LBW. In addition, arc stability was improved in hybrid of laser–TIG welding compared with using the TIG welding alone, especially at high welding speed and under low TIG current. It was found that the heat affect zone of joint was only observed in TIG welding, and the size of grains in it was evidently coarse. In fusion zone, the equiaxed grains exist, whose size was the smallest welded by LBW, and was the largest by TIG welding. It was also found that Mg concentration of the fusion zone was lower than that of the base one by EPMA in three welding processes.

Hybrid laser–TIG welding, laser beam welding and gas tungsten arc welding of AZ31B magnesium alloy

Experimental investigation of the effect of hydrogen in argon as a shielding gas on TIG welding of austenitic stainless steel

Tungsten?inert-gas welding arcs are modelled using a two-dimensional axisymmetric computational code. Both electrodes (the tungsten cathode and the metal anode workpiece) and the arc plasma are included self-consistently in the computational domain. The influence of adding helium, hydrogen and nitrogen to the argon shielding gas is investigated. It is found that addition of any of the gases increases the heat flow to and the current density at the anode. The shear stress and the arc pressure at the anode surface are increased by adding hydrogen or nitrogen or up to about 50?mol% helium, but decrease when more helium is added. It is predicted that the effect of adding any of the gases is to increase the depth of the weld pool, in agreement with the experimental evidence. The results are explained by referring to the thermodynamic and transport properties of the gas mixtures.

https://iopscience.iop.org/article/10.1088/0022-3727/42/11/115205/pdf

A computational investigation of the effectiveness of different shielding gas mixtures for arc welding

In order to understand the temperature fields, cooling rates and mixing in the weld pool, a comprehensive, three-dimensional heat transfer and fluid flow model is developed and tested by comparing ...

Numerical simulation of heat transfer and fluid flow in GTA/Laser hybrid welding

This paper deals with a combination of two different welding processes, i.e. the synergic action of two different heat sources for fusion welding. The major part of the paper is focused on the combined action of a welding arc and a laser beam. The main advantage of the use of both heat sources is more efficient use of the energy supplied. With certain parameters, the quantity of molten material increases by 100% compared with the sum of the individual quantities of molten material in the individual processes. The paper further presents several practical applications of the combined welding process. Eventually, development of arc augmented laser welding may progress in two directions; the first being the synergic effect of a laser beam and plasma welding arc and the second the combination of tandem laser welding and consumable electrode welding. This paper presents two such cases schematically.

J. Tus̆ek

Papers

Hybrid welding with arc and laser beam

Experimental research of the effect of hydrogen in argon as a shielding gas in arc welding of high-alloy stainless steel