Double side fiber laser welding: A novel welding technique to join thick plates

Stainless steel grade 304, is one of the most utilized grades of stainless steel and it is chosen for its corrosion resistance. The ideal option is 304, since its lower carbon content lowers intergranular corrosion, especially if corrosion resistance is a top goal for a project. This research work investigates the mechanical and microstructural characteristics of a novel double side fiber laser welded stainless steel 304 plates. Double side fiber laser welding technique is used to fabricate a butt joint with plates of thickness 5 mm. With a laser frequency of 25 Hz, speed of 6 mm & sdot; s-1, and a heat input of 1.4 kW in terms of power is applied to the joint, resulting in a maximum depth of penetration of 2.7 mm. The same parameter is applied on both sides of the plate. The dendritic structures are observed through micrographs of weld and pure metal captured using an optical microscope. Experiments such as tensile, bend, microhardness and impact test have been conducted to ensure the quality of weldment. The weldment consists of austenite and delta-ferrite. X-ray diffraction reveal presence of both austenite and ferrite in the weldment. Ductile mode of fracture occurred during failure of tensile samples. This study aims to provide comprehensive knowledge on the mechanical integrity and microstructural characteristics of fiber laser-welded thick stainless-steel plate. Coupon studies were conducted to ensure quality of the welded sample. The welded joint exhibited better mechanical properties than the pure metal. image