Laser fine cladding on miniature thin wall parts

Abstract

The surface hardening of miniature thin wall parts (MTP) are difficult owing to the special structure of MTP. A red copper heat carrier, which is designed as detachable structure, has been put forward for the laser cladding of MTP. An annular overlapping scanning method has been proposed. The microstructures are characterised by SEM, TEM and XRD. The hardness and the wear resisting property of cladding layer also have been tested. The results show that the laser cladding on the MTP obtains a complete success using the heat carrier and scanning method proposed in this paper. The laser cladding layer is comprised of a hypoeutectic structure, which contains primary dendrites and interdendritic eutectics. The primary phases are γ-Co, CoCx, Cr₂₃C₆, W₅Si₃ and [Fe, Ni]. The average hardness of coating layers is 814 HV0·1. Compared with the whole quenching specimens of Gr15 steel, the wear resisting property of the laser cladding specimen increases by five times.