Abrasive Wear Resistance of Medium Carbon Steel Treated by Laser Surface Alloying with C/B/Cr/WC Powders

In this paper CO2 laser surface alloying technology was adopted to improve the abrasive wear resistance of medium carbon steel. Carbon (C), boron (B), chromium (Cr) and tungsten carbide (WC) powders were used as the alloying materials to harden the medium carbon steel by changing the composition and the microstructure of its surface layer. Both of the characteristics including cross-sectional morphologies, phases and microstructure and the properties including hardness and wear behaviours of the alloyed samples were investigated. The results indicate that a continuous and uniform alloyed layer free from cracks can be obtained on medium carbon steel. The abrasive wear resistance of laser alloyed layers is enhanced by 2.7 to 62% compared with that of the steel substrate, which is due to the enhancement of hardness in the alloyed regions caused by the reduction of grain size, the formation of martensite, the solid solution of alloying element or the dispersed WC particles. Of all samples tested, those treated by laser surface alloying with WC powder had the best wear resistance.