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As a fusion welding process, Laser welding has proven to be the most promising method for joining of different materials whether it can be either a similar or dissimilar material category.

In the present work, fabrication of similar Stainless Steel (SS) 304 joints by Nd-YAG Laser Welding Process (LWP) was done. A novel approach was attempted in this study. Welding was performed on dual sides of the plate (top and bottom) for a better mixture of micro powder particles in the weld pool region to achieve maximum depth of penetration, which is not easily possible in a single-sided LWP. High depth of penetration during fabrication of joints, significantly improved the mixture ratio of molten steel with reinforced micro powder particles. Al2O3 micro powder particles were reinforced in the weld pool region through the drilling process with varying depth ratios, and a moderate gap was maintained between each hole. The effects of Al2O3 on the microstructure and mechanical properties were studied and elaborated. Totally 12 samples were fabricated and joining was performed keeping the frequency as constant and varying laser power, travel speed for all the trials.

Tensile and axial fatigue tests were conducted on shallow cryogenically treated EN19 medium carbon alloy steel to investigate its mechanical behavior. The test samples were conventionally heat treated then oil quenched at room temperature. Followed by the samples were kept for shallow cryogenic treatment to -80°C for 8 hours using liquid nitrogen. Then the samples were tempered in a muffle furnace to relieve the induced residual stresses. Tensile and axial fatigue test were carried out on both treated and non-treated samples to measure its tensile strength and fatigue behavior respectively. Microscopic examination also had done to compare the effect of shallow cryogenic treatment on its microstructure. The results exposed that there is an increase in the tensile strength and reduction in fatigue life of shallow cryogenically treated samples over base metal and improved wear resistance.