Improved hardness of laser alloyed X12CrNiMo martensitic stainless steel

Abstract

The improvement in hardness of X12CrNiMo martensitic stainless steel laser alloyed with 99.9% pure titanium carbide, stellite 6 and two cases of premixed ratio of titanium carbide and stellite 6 [TiC (30 wt.%)- stellite 6 (70 wt.%) and TiC (70 wt.%)- stellite 6 (30 wt.%)] were examined. The powders were supplied through a pneumatically driven powder delivery system with a 4.4 kW continuous wave (CW) Nd:YAG laser. The microstructures of the alloyed zones were investigated by x-ray diffractometer (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The alloyed zones obtained by alloying with premixed ratio of 70 wt.% TiC and 30 wt.% stellite 6 were free from dilution and crack that were in those of pure stellite 6. A significant increase in Vickers hardness value compared with that of the substrate was achieved with the powders and their premixed ratios; 608 HVN for TiC and 503 HVN for stellite 6, 763 HVN for 30 wt.% TiC and 1025 HVN for 70 wt.% TiC.