Laser Beam Welding of Stainless Steels: Experimentation, Modeling and optimization

The main objective of this research is to study the laser beam welding of stainless steels. During experimentation, a 1.1kW CW Nd:YAG laser is used to weld similar and dissimilar stainless steels in overlap and fillet joint configurations respectively. Various process parameters and their interactions effects on weld geometry and its mechanical properties are examined. Effects of energy density and line energy on the weld bead characteristics are investigated to understand certain energy dependent welding phenomena. Formation of solidification microstructures and the distribution pattern of the segregated alloying elements in the weld with varied energy input are studied and correlated with the corresponding change in local microhardness. In order to predict and optimize the laser welding of stainless steels used in automotive industry, full factorial design and response surface methodology are respectively used as a design of experiment approach to design the experiments, develop the mathematical models, and optimize the welding operation. Finally, a simplified energy-based model is developed for laser welding of ferritic stainless steels in overlap joint configuration.