Mechanical and Microstructural Characterization of 8 mm Thick Samples of SS 316L by CO<sub>2</sub> Laser Welding

Abstract

Laser beam welding offers various advantages over the other conventional weld processes. In fusion reactor, some critical components with high weld quality are proposed to be fabricated with Laser beam welding. The present paper reports the mechanical properties and micro structural characterization of 8 mm thick SS 316L samples fabricated with high power CO2 Laser welding system. The process parameters of 3.5 kW and speed of 600 mm/min with Argon shielding gas are used. The Laser welded samples are subjected to non destructive testing with X-ray radiography and ultrasonic tests. The welded samples tested have indicated good quality joints with full penetration and no significant porosity and cracks. Further, the samples are subjected to standard mechanical tests namely tensile properties test (UTS), bend test and Impact Fracture test. The Laser weld joints produced better tensile properties as compared to the base metal. In addition, Vickers hardness tests and optical microstructure are studied for the base metal (BM), Heat Affected Zone (HAZ) and weld zone(WZ).