Additive Repair of Cast Iron Materials using Coaxial Laser Wire Cladding

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.