Preparation and microstructure analysis of cladded layer strengthened by spherical WC particles with very high volume fraction

NiCrBSi coatings of different thicknesses were pre-coated on low carbon steel substrates and melted with an argon arc. Spherical WC particles were injected into the molten pools. Cladded layers with very high volume fraction of WC particles had been produced. Microstructures of the cladded layers were analyzed with scanning electron microscopy. Volume fraction of WC particles were measured and calculated. Dissolution ratio of WC particles was estimated. The results show that, microstructures of the cladded layers consist of (Fe, Ni) solid solution, WC particles, Fe₃W₃C carbides, and eutectic structures. WC particles are distributed uniformly in the matrix. Volume fractions of WC particles in the cladded layers are as high as 68.7-76.6 vol.%, and the corresponding mass fraction are 79.5-85.2 wt.%. Dissolution ratio of WC particles is very low, estimated as less than 12.2 wt.% based on microstructures, and as less than 7.4 wt.% based on energy dispersion spectrum results. Increase of pre-coatings’ thickness benefits increase of volume fraction and decrease of dissolution ratio of WC particles.