Characterizing the Mechanical Performance of Laser Welded Lap Transverse Fillet Joints of Thick AISI 316L Stainless Steel

Fillet and double fillet welding are extensively used in numerous structural applications around the globe. Laser welding technology has achieved great appeal due to its superior quality, accuracy, speed, adaptability, and versatility. The present investigation examines two modes of transverse welding, namely single fillet and double fillet weldments, on austenitic 316L stainless steel sheets with a thickness of 3 mm. The welding was performed using a CO2 laser, eliminating the need for filler material. The mechanical performance was evaluated through tensile shear, bending, and micro-hardness tests. The investigation revealed a notable correlation between the laser power and scanning speed as working parameters on the joint's strength. The analytical results indicated that the optimal working parameters were a laser power of 2.75 kW and a scanning speed of 5 mm/s. These parameters resulted in a yield strength of 186.98 MPa and 275.91 MPa for the single fillet joints and double fillet joints, respectively. The three-point bending test showed flexural yield strength of 328.73 MPa and 893.57 MPa for the single and double fillets, respectively. The area under the flexural stress-strain curve reveals high ductility for both joining modes, represented by the broad area under the curve. This refers to the energy consumed per unit volume required to bend and deform the weldment until fracture.