Study on microstructure and properties of 304/316L coating prepared by ultra-high frequency induction cladding with wire feeding

Abstract

To improve the surface properties of blade tip made of 304 stainless steel, 316L stainless steel wire was coated on the substrate by ultra-high frequency (UHF) induction heating technology. Optimized process conditions were determined by analyzing the results of orthogonal experiments. The feasibility of this method was confirmed by studying the element distribution of coating. Distributions of temperature field and residual stress were simulated and analyzed by finite element method. The microstructure, tribological properties and corrosion behaviors of the coating were investigated. Surface morphology after experiment was measured. Parameters of the maximum dilution ratio in a certain extent were the optimal process parameter set, which was heating power ratio of 93%, wire feeding rate of 2.7 mm/s, moving speed of 2.8 mm/s, distance between substrate and induction coil of 1.0 mm, preheating temperature of 823.15 K. Friction coefficient of as-prepared coating was about 0.5, which is nearly 30 % lower than that of the substrate. Weight loss of substrate is 4 times that of the cladding layer of 0.1 mg. Mainly wear mechanism transformed from adhesive to abrasive. Capacitive arc of the coating in the low-frequency region was increased so that the surface is more capable to form a passive film. 304/316L coatings improve wear resistance and anti-corrosion. And this technology can be widely used for thermal repair of the blade tips.