Multi-pass Route Planning for Thick Steel Plate Using Laser Welding with Filler Wire

Abstract

Laser welding with filler wire, performed by welding robots, provides high stability and efficiency for welding thick plates used in shipbuilding, electrical engineering and nuclear industry. The route planning methodology is of central importance in this process. Firstly, build a welding system suitable for thick plate laser building with filler wire. Then, establish a strategy on the principle that the cross section areas of the welding beads are equal under same welding parameters, parallelogram/trapezoid method is applied to plan the layers, number of beads for each layer, and the concrete position for each bead before the welding for both V-shape and trapezoid grooves. Auto-planning and visualization are achieved by programming. Furthermore, a specially designed method for welding capping layer, concerning the coverage of the edges of the groove, is introduced to perfect the joint quality. Finally, experimental test shows the effectiveness of this planning philosophy in laser welding with filler wire of thick plate. Testing results highly agree with the planning with only slight differences in both normal and capping layers. High quality leveling interface and fusion can be realized after filler passes based on the multi-pass route planning.

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“…The welding parameters should be reduced in the whole multi-layer and multi-pass welding as much as possible, to ensure the weld quality, and to make the whole welding process more convenient. Therefore, it is necessary to plan weld bead filling for multi-layer and multi-pass welding (Huang et al , 2014), so that the groove section area of each weld is approximately equal.…”