Effect of Laser Beam Mode on the Microstructural Evolution in AISI 410 Martensitic Stainless Steel Welds

Autogenous laser welding of AN 410 grade martensitic stainless steel was carried Out using a diffusion cooled RF excited CO2 slab laser with Gaussian and Donut modes. The effect of the mode of the laser beam, energy density and power density on the resultant weld bead geometry, microstructural evolution and hardness were assessed. Welds free from defects could be obtained in both the Gaussian and Donut modes. Even though the welds produced in the Donut mode resulted in a larger bead and higher heat affected zone width, they were found to have a better microstructural balance and uniform distribution of hardness.