Influence of Laser Power on Interface Characteristics and Cracking Behavior During Laser Remanufacturing of Nodular Cast Iron

Nodular cast iron shows poor weldability due to obvious crack tendency caused by chilled structure in interface region during welding and cladding process. However, chilled structure could be eliminated by controlling interface heat input during laser cladding process. In this paper, brazing interface characteristic with no chilled structure could be obtained by controlling the heat input of the interface, and the results showed that the brazing interface illustrated higher strength compared with the chilled structure interface. The results illustrated that the tensile strength of specimens with brazing and intermittent chilled structure characteristic could reach 564 MPa. However, tensile strength of specimens with continuous chilled structure characteristic was lower than 353 MPa. Cracks formed in the interface zone and extended to the ledeburite region. FEM method with the help of ANSYS software was adopted to determine the thermal cycles of the interface region during the cladding process, and the mechanism of the interface behavior was studied.