Joining metallic alloys can be an intricate task, being necessary to take into account the material characteristics and the application in order to select the appropriate welding process. Among the variety of welding methods, pulsed laser technology is being successfully used in the industrial sector due to its beneficial aspects, for which most of them are related to the energy involved. Since the laser beam is focused in a concentrated area, a narrow and precise weld bead is created, with a reduced heat affected zone. This characteristic stands out for thinner material applications. As a non-contact process, the technique delivers flexibility and precision with high joining quality. In this sense, the present review addresses the most representative investigations developed in this welding process. A summary of these technological achievements in metallic metals, including steel, titanium, aluminium, and superalloys, is reported. Special attention is paid to the microstructural formation in the weld zone. Particular emphasis is given to the mechanical behaviour of the joints reported in terms of microhardness and strength performance. The main purpose of this work was to provide an overview of the results obtained with pulsed laser welding technology in diverse materials, including similar and dissimilar joints. In addition, outlook and remarks are addressed regarding the process characteristics and the state of knowledge.

Plates joining is one of the first stage at large vessels manufacturing line, process conditioning the whole shipbuilding production. Laser Arc Hybrid Welding (LAHW) process is nowadays providing promising results for large thickness naval steel, being primarily used for welding plates with thicknesses between 6 to 15 mm, reaching up to 51 mm. In addition to this high penetration ability, LAHW allows increasing the production rates. Therefore, this technology is proposed as an alternative to conventional welding processes in shipbuilding, as it integrates the advantages of laser and arc welding, providing high process stability, high welding speed and penetration, narrow weld beads with a low heat input and good metallurgical properties. The present review reports the most representative investigation regarding the use of this technology to join large thickness flat panels of naval steel. It includes a summary of the most influential process variables, equipment characteristics, material properties, naval regulations, as well as microstructural characterisation and mechanical properties of joints. This review is thought to help readers from different backgrounds, covering from non-expert on welding or on naval sector, to industrial LAHW applicators and researchers. The industrial need of performing one single pass procedure to assure high quality welds of high thickness is suggested as one of the key aspects for future investigations.