GMA surface welding with flat wire electrodes - an economically viable alternative to the conventional high-productivity welding processes

With the research project relating to GMA surface welding with flat wire electrodes, fundamental development work was performed in the field of flat wire welding. In the course of the project at SLV München and SLV Halle, the installation technology was tested in detail and refined constantly. Thus, a level which permits the introduction of the process into practice was reached at the end of the research project. Terms of reference with regard to welding with flat wire were processed at SLV Duisburg as well.

The objectives of the surface welds with corrosion-resistant CrNi, Ni based and CuNi flat wire electrodes were attained, i.e. obtaining a high deposition rate and weld quality and a sufficient corrosion resistance of the specimens already in the first pass and thus highlighting the productivity of this process variant.

With optimised welding parameters and working and boundary conditions as well as with a flat torch position and suitable shielding gases, degrees of dilution < 6 % are achieved in the first pass at deposition rates up to 15 kg/h with the corrosion-resistant CrNi, Ni based and CuNi coats. Especially with the Ni based flat wire electrodes, braze-metal-like joints can be manufactured in a reproducible way with the lowest degrees of dilution (< 3 %) without any lack of fusion to the carrier material. Wear protection coats can be manufactured with both solid and flux-cored flat wires.

The surface welds with welding fillers from various alloy groups are reaching very promising values in practice-related wear investigations and impact toughness tests. Investigations on real, extremely wear-afflicted components from mining and mechanical engineering are resulting in a substantial rise in the welding speed during GMA surface welding with flat wire electrodes in comparison with the technology utilised until now.

The results obtained in the research project are serving to create good prerequisites for establishing GMA flat wire surface welding as a versatile and economically viable process in practice in the future.