Tailoring laser cladding paths for improved coating performance: A comprehensive investigation

Abstract

This study explores the influence of laser cladding scanning paths on the microstructure and properties of coatings by employing a combination of numerical simulations and experiments. Two novel scanning paths, namely a segmented guided scanning path inspired by the "back welding method" and a real-time temperature feedback scanning path, are introduced and analyzed alongside the conventional one-way sequential scanning methods. The research reveals that the microhardness distribution within the coating is strongly affected by the scanning method. Notably, the one-way sequential scanning method yields the highest microhardness, followed by segmented guided scanning, and finally real-time temperature feedback scanning path. Segmenting the scanning path does not contribute to uniform microhardness distribution, particularly at the overlapping positions. Furthermore, the temperature gradient within the coating during the entire cladding process is significantly influenced by the scanning method. Segmented scanning reduces the temperature gradient compared to single long-path scanning, and further improvements are achieved through path optimization based on real-time temperature feedback. The residual stress levels on the coating surface also differ among scanning methods. Conventional one-way sequential scanning results in a residual stress of 727.0 MPa, while segmented guided scanning produces a higher residual stress of 1041.0 MPa. In contrast, the real-time temperature feedback path generates a lower residual stress of 680.0 MPa on the coating surface compared to the other two methods. These findings underscore the importance of selecting an appropriate scanning path for laser cladding processes. Optimized scanning paths not only reduce the tendency of gray cast iron to form martensite and the temperature gradient but also result in lower residual stress levels on the coating surface. This research provides valuable insights for enhancing the performance of laser-clad coatings in various industrial applications.