The powder-feed laser additive manufacturing method was applied to rebuild GTD 450 martensitic stainless steel specimens with Stellite 6. The H-factor parameter was defined as the controlling factor based on the values of the laser power, the cladding speed and the powder feed rate. By depositing upper layers, cellular dendrites turned into columnar ones, which grew in the direction of heat transfer. A mixture of Co-rich γ and complex carbides of Cr, W and Mo were found in the microstructure. The dilution was decreased with increasing the number of deposited layers; consequently, the increase in the hardness from the base metal to the cladded area was observed due to the less dilution by the base material as well as the less tempering effect of subsequent layers. The increased cladding speed decreased the H-factor. It was observed that by controlling the H-factor, the wear properties of cladded parts were increased by 8%.

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