Influence of low speed-wire electrical discharge machining strategy on surface roughness and quality of laser cladding Ni204

Abstract

To address the key issues of surface accuracy and interface bonding in rack remanufacturing, this study proposes a remanufacturing strategy that couples laser directed energy deposition (L-DED) with low-speed wire electrical discharge machining (LS-WEDM). The effects of the machining strategy on the surface roughness, metamorphic layer thickness, and subsurface grain size of Ni204 layers were systematically investigated. Four machining strategies were designed, namely: rough cutting (RC), RC + trimming 1 (T1), RC + T1 + trimming 2 (T2), and RC + T1 + T2 + fine cutting (FC). The surface roughness of procedure 1 is 4.173 μm, while that of procedure 4 is reduced to 0.634 μm. By regulating the energy input of machining steps in each procedure, the average size of subsurface grains is reduced by 18.4 %; this regulation also promotes directional grain growth, with the proportion of low-angle grain boundaries increasing from 25 % to 45 %. Additionally, a 2.61 μm elemental buffer zone is formed at the interface via Ni-Fe interdiffusion, and the bending strength reaches 1375.8 MPa (quenched and tempered 45# steel, bending strength ranges from 900 – 1200 MPa). This study provides a process basis for the high-precision remanufacturing of complex components.