EFFECT OF WELDING SPEED ON THE MECHANICAL PROPERTIES AND MICROSTRUCTURE OF LASER WELDED AISI 316L STAINLESS STEEL

In this study, AISI 316L (X2CrNiMo17-12-2) austenitic stainless steel plates were joined with CO2 Laser Beam Welding (LBW) method. The welding process were carried out in 50% Ar+50% He shielding gas atmosphere by using 3500W laser power for 90-180-270 cm/min different welding speeds. The samples were joined autogenously in butt welding position without using filler metal. In order to determine the mechanical properties of welded joints, the tensile, charpy impact and three point bending tests were applied. In addition, the hardness of the welded sample was measured on the cross section. The microstructure characterization of welded samples was carried out using with optical microscope, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), elementel mapping and X-ray diffraction (XRD) analysis. As a result of this study, it was found that the mechanical properties of AISI 316L weldment recovered and the microstructure morphology of weld metal altered by increasing laser welding speed due to high cooling rate.