HAZ Characteristics of Laser Cladding Remanufacturing Ductile Iron Component

Ductile cast iron is a ferrous alloy characterized by spheroidal graphite, and it is difficult to be remanufactured own to the complicated phase evolution. In this work, laser cladding using Ni-Cu based alloy power as the cladding material has been completed. The grain morphology of cladding and related phase evolution in partially melted zone (PMZ) and heat affected zone (HAZ) by single pass and multi layer cladding have been investigated. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive microanalysis (EDS) were used to identity the microstructure and phase composition of cladded layers and interfaces. Microhardness of the samples was evaluated after laser cladding. The result revealed that entirely different phases were formed by single pass and multi layer cladding progress. Nickel, carbon, and copper elements migrated apparently across the interface. It was also found the microhardness of the substrate was lower than that of the cladded layers, PMZ and HAZ. In samples processed with single pass and multi layer cladding, microhardness in PMZ reached up to 900 and 800 HV respectively.