ABSTRACT
Lasers as a source of high-intensity heat may be utilized efficiently to fuse materials by fusion welding in either autogenous or hybrid modes. Welding is carried out in autogenous mode in conduction, deep penetration, and keyhole modes. However, owing to the inherent high energy density of a laser source, autogenous keyhole welding is the most often used mode of laser welding. However, it has several drawbacks, such as the requirement of good fixture for exceptionally good joint fit-up, the creation of exceedingly hard welds in steel, keyhole instability, and alloying element loss. As indicated previously, achieving laser-based joining involves the suitable selection of laser source, beam delivery system, processing head equipped with appropriate optics, and accessories. This chapter discusses the fundamental concepts of various laser-based joining techniques, process dynamics and properties of laser welding, the primary characteristics of the welding lasers, the process parameters that effect weld penetration, and laser welding phenomena such as laser-induced plume behavior, keyhole behavior, and melt flows in a molten pool during laser welding. Additionally, it relates to welding faults and the metallurgical effects on various base materials, joint performance, and applications.
