Influence of process parameters on surface properties and corrosion resistasnce of Inconel 625 coating prepared by laser cladding

Abstract

To obtain good corrosion resistance and save cost, Inconel 625 coating was prepared by laser cladding with different process parameters, and the Inconel 625 powder play as feed material. The influence of powder feed rate (Vp), scan rate (Vs) and laser power (P) on the surface waviness (Wa) and effective height (he) of the cladding was analyzed. The results indicate that the Wa and he increase with the increase of Vp, while decrease with the increase of Vs. In addition, the P has positive influence on the he. When the P is lager than 1.0 kW, P boost the increase of Wa. Otherwise the influence is opposite. The microstructure of the cladding exhibiting relative good formation quality was studied using X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS). It demonstrates that the cladding is mainly composed of γ-Ni matrix and laves phase. Many coarse columnar and cellular crystals are distributed at the previous clad near the fusion line, while the other side is mainly composed of fine and dense columnar crystal. The process parameters have influence on size of grains and laves phase. For the relative good formation quality, the most positive Ecorr, the smallest Icorr, and largest Epit, the cladding marked No.3 possesses more outstanding comprehensive corrosion resistance than others. It is concluded that big grains size and less number of laves phase is benefit to the corrosion resistance.