Study on the microstructure and wear resistance of laser clad martensitic stainless steel 420 with different content of TiC

Laser clad martensitic stainless steel 420 (420 MSS) has great potential for strengthening the surface and remanufacturing key components in precision machinery, bearings, and cutting tools. However, the wear resistance of laser clad 420 MSS coating is currently facing increasingly severe and demanding environmental challenges. Therefore, this work utilized mechanical mixing to prepare TiC-420 MSS composite powders with different composition ratios and systematically studied the phase composition, microstructure, and wear resistance of laser cladding TiC-420 MSS composite coatings, revealing the mechanism of performance enhancement. The results show that the microstructure of 420 MSS coating after laser cladding was mainly columnar crystal. The microstructure of composite coatings was transformed to equiaxed crystal after the addition of TiC, refining the grain. The overall microhardness and wear resistance of the coating were significantly improved. The composite coating with 6 wt% TiC has the highest microhardness. The composite coating with 4 wt% TiC has the best wear resistance with only 25 % of the wear volume of the 420 MSS coating. The grain refinement and the resistance of TiC particles are responsible for friction pairs during friction. Strengthening mechanisms such as abrasive wear, adhesive wear and oxidative wear exist in all coatings, and the abrasive wear are gradually weakened with the increase of TiC content. The results of this study can provide theoretical and technical guidance for laser clad TiC reinforced 420 MSS for enhanced wear property.