Process Optimization for In-situ Synthesized WC Reinforced Fe-based Alloy Coating by Reactive Plasma Cladding

The plasma cladding schemes were designed by the four-factor quadric orthogonal rotating regression design method. Based on these schemes, the WC reinforced Fe-based alloy coating were in-situ synthesized on the surface of Q235 steel and the optimum process was obtained. The microstructure and properties of the coating prepared under the optimum process were also studied. The results show that the optimum process parameters of the coating were listed as follows: C/W atomic ratio of 1.4, tungsten content of 20wt%, cladding current of 130 A and cladding rate of 100 mm·min-1. The coating prepared with the optimum process showed a good metallurgical bonding with the substrate; the microstructure of the coating mainly consisted of planar crystal, cellular crystal, dendrite crystal and equiaxed crystal and the phase composition was composed of α-Fe, M23C6 and WC; the sectional hardness of the coating was up to 1 120 HV and the surface average hardness was 68 HRC.