High Power Fiber Laser Welding of Single Sided T-Joint on Shipbuilding Steel with Different Processing Setups

Abstract

Laser welding of thick plates in production environments is one of the main applications of high power lasers; however, the process has certain limitations. The small spot size of the focused beam produces welds with high depth-to-width aspect ratio but at times fails to provide sufficient reinforcement in certain applications because of poor gap bridging ability. The results of welding shipbuilding steel AH36 with thickness of 8 mm as a single-sided T-joint using a 10 kW fiber laser are presented and discussed in this research paper. Three optical setups with process fibers of 200 µm, 300 µm and 600 µm core diameters were used to study the possibilities and limitations set by the beam delivery system. The main parameters studied were beam inclination angle, beam offset from the joint plane and focal point position. Full penetration joints were produced and the geometry of the welds was examined. It was found that process fibers with smaller core diameter produce deeper penetration but suffer from sensitivity to beam positioning deviation. Larger fibers are less sensitive and produce wider welds but have, in turn, lower penetration at equivalent power levels.

Special Issue on Solid State Lasers Materials, Technologies and Applications

“…In this paper, a comprehensive overview on laser welding under vacuum is presented, which is a recently re-discovered laser welding technique [12] that can help in fully exploiting the potential of recently available high-power and high-brightness solid-state fiber and disk lasers. A study on high-power (10 kW) fiber laser welding of stainless steel T-joint focused on the investigation of the impact best fiber core diameter selection is presented by A. Unt, I. Poutiainen, S. Grunenwald, M. Sokolov, and A. Salminen in [13]. The effect of welding position on the quality of the laser welds is investigated in detail by B. Chang, Z. Yuan, H. Pu, H. Li, H. Cheng, D. Du, and J. Shan in [14], where a high-power (6 kW) fiber laser is used to weld titanium alloys.…”

Effect of collapse and hump on thermomechanical behavior in high-power laser welding of 16-mm marine steel EH40

“…Laser welding has become an important method of marine steel plate joining because of the advantages of high-power density, low thermal distortion, rapid welding speed and so on. Unt et al [1] investigated laser welding of single sided T-joint on shipbuilding steel. It was reported that T-joints single-sided full penetration welding of AH36 with thickness of 8 mm were realized, possible cracks in fillet welds were avoided successfully.…”

Recent Developments in Laser Welding of Aluminum Alloys to Steel

“…Thus, low-heat input welding processes facilitate controlling the formation and growth of the IMC layer, leading to better mechanical performance. In this context, laser welding stands out as a very precise technique [17,18], which enables accurate control of heat input [19] and high cooling rates due to its very high energy density [20].…”