Additive Repair of Cast Iron Materials using Coaxial Laser Wire Cladding

Abstract In contrast to most steels, almost all cast iron materials are considered problematic in terms of welding. Today, arc-based welding of dissimilar bonds and the associated welding sequences at low pre-heating temperatures are established in the industrial environment. However, this processing routine, e.g. for repair or cladding, often appears to be no alternative for many components, where a low heat input and a wider range of filler metals in contrast to the application need to be considered. In this context, laser-based technologies constitute valuable tools for cast-iron repair and are seen as future approaches for thermal processing of demanding materials without the need for pre- or post-heating. Nowadays, the possibilities offered by wire-based laser processes allow for material-efficient manufacturing approaches, such as the repair and processing of worn-out, cast-iron components. As an example, the successful repair of cast iron materials, viz. GJS and GJL, using a self-developed coaxial laser wire cladding technology is presented. The laser system has been used to investigate cast-iron repair by hot wire deposition without pre-heating the substrates. Selected process strategies with defined parameters and tool path sequences have been used to repair industrially applied cast-iron parts. While the heat input is mainly dissipated in the filler metal during processing, a low dilution and minimal martensite formation in the transition zone could have been achieved under different process conditions (welding position, filler metal material – NiTi4, FeCrMoVC). The gained flexibility in cast-iron repair addresses the potential for future concepts in the field of industrial remanufacturing.