High-efficiency fabrication of Inconel 625 coating for AISI 1045 carbon steel through laser cladding with hot wire: Microstructure and wear resistance

Abstract

Laser cladding has been widely used to prolong the service life of components by preparing wear-resistant coatings on the surfaces of engineering parts. However, the efficient fabrication of large-area coatings with desired properties remains a challenge for traditional laser cladding methods. In this paper, based on laser cladding with hot wire, the Inconel 625 single track with desirable geometrical characteristics was first prepared under the stable liquid-bridge transfer mode of the filler wire. Then, defect-free multi-track Inconel 625 cladding layers were fabricated on the surface of the AISI 1045 steel shaft and plate with a higher wire deposition rate of 1.72 kg/h and lower deposited line energy of 61.3 J/mm. The microstructure, phases formed, microhardness, and wear resistance of the cladding layer were investigated. The results indicated that the microstructure of the Inconel 625 cladding layer was mainly composed of a large number of columnar dendrites, with an average grain size of 12 μm. The growth direction of the columnar dendrites in the single deposited track was perpendicular to the substrate surface while it was between 50° to 90° in the multi-track cladding layer. γ-Ni (FCC) was the main phase presented in the Inconel 625 cladding layer. The dilution ratio of Fe was 6 % because of the lower line energy applied in the deposition process. The average microhardness of the Inconel 625 cladding layer was 262 HV1, which was 27.8 % higher than that of the substrate. Inconel 625 cladding layer experienced adhesive wear with a lower friction coefficient of 0.572 and a minimal wear loss of 0.442 × 10−3 g. Similar to microhardness, Inconel 625 cladding layer exhibited better wear resistance than the AISI 1045 steel substrate at room temperature under dry sliding conditions.