On the Use of Laser Beam Welding for Austenitic Stainless Steel Type 316L and Stainless Steel Type 304 for Aerospace Applications.

Abstract

Currently wide range of aircraft parts have been welded by using laser beam welding. In this paper we have analyzed the strength of laser beam welded joint of stainless steel materials 316 L and 304. The Micro and Macro welding techniques are used for dissimilar stainless steel materials. The metal sheets are welded with a laser power of 1000 w with a bead width of 0.5 mm on both sides of the sheet by using micro laser beam welding and the macro laser beam welding is used to weld the metal sheets with 1800 w laser power along with a bead width of 3mm on one side of the sheet. The strength and mechanical properties of laser beam welded samples are found out by subjecting it to various tests such as Tension test, Bend test and Hardness test. Since stainless steel used in the aircraft parts are subjected to high temperature in the engine exhaust part, these samples are heated to temperature of 1040ºC. Aircraft icing occurs on parts of aircraft, where temperature falls below 0ºC, hence laser beam welded samples are cooled to a temperature of -30ºC. The behavior of laser beam weld portions under these conditions are studied. The Microstructure of the welded sample is obtained from the Scanning electron microscope is also discussed. The results obtained from the tensile test are compared with the structural analysis done using Finite Element Analysis. From the results we found that, macro welded sample is having good tensile strength of 582.753 MPa and no cracks were occurred during the bending test.