Machinability investigations on turning of Cr-Ni-based stainless steel cladding formed by laser cladding process

Abstract

Laser cladding process has been developed to be an advanced surface modification technique in re-manufacturing and maintenance fields. Service performance of the component formed by laser cladding largely depends on its subsequent finish cutting processes. Depth of cut in cladding turning process was restricted relatively small due to the thickness limitation of cladding layer, which reflected distinctive and crucial compared with cutting operations of homogeneous materials. The effect of depth of cut on turning performance of Cr-Ni-based stainless steel formed by laser cladding was investigated in this paper to get a novel insight into the machining process of cladding layer. Larger cutting force, worse surface roughness, and strengthened work-hardening with depth of cut increasing were observed similar to a conventional turning process. However, radial force rather than tangential force dominated especially in the given cutting conditions owing to the shallow depth of cut. Both surface roughness parameters Rz and Rt exhibited twice larger when the depth of cut exceeds 0.18 mm. Furthermore, comprehensive machinability of turning process was quantitatively evaluated based on modified digraph and matrix method so as to obtain a superior functional cladding. The results indicated that the machinability of cladding layer became worse with depth of cut increasing initially. The machinability value reached the worst level with depth of cut equaling to 0.24 mm. Thus, an optimized depth of cut was determined as 0.12 mm for turning of laser cladding Cr-Ni-based stainless steel. It should be noted that tool vibration should be eliminated for improved surface roughness as well as work-hardening with the depth of cut increasing, which performed beneficial to the machining of functional component formed by laser cladding.