EFFECT OF FOCAL POSITION ON THE MICROSTRUCTURE AND TENSILE STRENGTH OF Nd: YAG LASER WELDED UNS S32750
Keywords:
YAG laser welding, super duplex stainless steel, Microstructure, tensile strengthAbstract
Laser welding is a fusion welding process during which radiant energy is employed to generate necessary thermal energy for achieving a strong weld. This study reports the effect of varied laser focal positions on the weldability, microstructure and mechanical strength of super duplex stainless steel (UNS S32750) by a 600 W pulsed Nd: YAG laser welding machine. Porosities were observed on the weld zone, when the laser beam is positioned above the surface; whereas, a good weld devoid of undercut and porosities emerge, when the laser beam is positioned either on or below the surface. The micro-hardness and tensile strength of the joints is higher, when the laser beam is positioned below the base alloy.
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