TWI Industrial Member Report Summary 860/2007
Part A: Hybrid Nd:YAG laser-MIG welding 6mm thickness alloy
By C M Allen
The work presented in this report formed part of a DTI supported, TWI managed collaborative project, DEFUSE (Development of Fusion Welding Methods for Wing Primary Structures), along with Airbus UK, Alcoa Europe, Cranfield University, Manchester University, and QinetiQ. The overall objectives of this three year project were to develop fusion welding techniques as alternatives to existing joining processes for fabrication of aircraft wing structures. Successful implementation of fusion welding in these areas will significantly reduce weight, improve performance and reduce costs.
The report covers trials on both autogenous and hybrid laser-MIG single pass welding of a 7xxx Al-Mg-Zn-Cu alloy, using 3.5kW of Nd:YAG laser power, on material 6mm thick. These trials supported a more extensive work programme carried out on 12.7mm thick plate of the same composition, butt welded using a 7kW Yb-fibre laser source (4), the results of which are available as a TWI Members Report (5). Other partners in the collaboration were responsible for the metallurgical assessment of the welds produced and establishment of their mechanical and corrosion related properties. However, due to reasons of confidentiality, this report refers only in part to these results.
- To develop a single pass hybrid Nd:YAG laser-MIG welding procedure to butt weld 6mm thick 7xxx aluminium alloy.
- To compare the resulting internal weld qualities, in particular related to weld metal porosity, with the limits of the quality classes defined in both BS EN ISO 13919-2 and AWS D17.1.