Investigations of properties in hybrid welds at 40-mm sheet thickness

Abstract

Laser gas metal arc hybrid welding (laser-GMA hybrid welding) offers capabilities for improving the economy of welding in comparison to conventional welding processes due to characteristics concerning material and seam design. Research into this process was restricted to a sheet thickness range of between 6 and 12 mm for steel. However, for steel, container, vehicle or ship engineering in particular, structures (components) with large wall thicknesses are of special interest. These structures are currently welded by using the submerged arc welding process, which requires a high input of energy, welding material and working time. The objective of this project was to determine the influence of the reduction of the weld volume and energy per unit length of weld on the formation of residual stresses and their effects on the fatigue strength of hybrid welded sheets with large wall thicknesses. As a result, better qualities with regard to fatigue strength and toughness have been achieved for hybrid welded joints in comparison to submerged arc-welded joints for wall thicknesses of 40 mm.