Physical study of hybrid Nd:YAG laser-mag welding process

Compared to laser or arc welding used separately, hybrid laser-MAG arc welding show decisive advantages when higher welding speeds, thicker materials, joint fit-up allowance, better molten pool stability, increase of metallurgical joint quality are required. The understanding of the main relevant involved physical processes are therefore very necessary if one wants for example elaborate adequate simulations of this process. Also for an efficient use of this process, it is necessary to precisely understand the complex physical phenomena that govern this welding technique. This paper will first discuss different results that concern the analysis of the main physical processes controlling this hybrid welding. Melt pool depression due to arc pressure is an important physical phenomenon that defines the location where the arc deposits it energy onto the melt pool surface. We will discuss this effect from related experiments and show how it can be taken into account by using corresponding 3D numerical simulations describing the thermal and hydrodynamic field of the melt pool by taking into account its 3D free surface.