ANALYSIS OF THE LASER-CLADDING PROCESS FOR STELLITE ON STEEL

Laser-cladding experiments have been performed with STELLITE 6 powder on mild steel substrates, using a 1.5 kW linearly polarized continuous wave CO2 laser as a heat source. The clad height, the mass efficiency , the dimensions of the melt pool, as well as the global absorptivity, were measured as functions of the powder feed rate and the scanning s peed. A quantitative analytical model of the process is proposed, base d on the overall mass and energy balance. It allows the calculation of the mass efficiency and of the global absorptivity, taking into accou nt the incorporation of the powder into the melt pool as well as the e nergy absorbed by the powder jet and the substrate. It successfully ex plains the experimental results and demonstrates the role played by th e melt pool inclination with respect to the substrate. A processing di agram is given to find rapidly the optimal laser treatment conditions and the desired clad height. It is discussed with respect to the other limiting conditions of the process, the geometrical maximum powder ef ficiency, the porosity, the dilution, and the maximum power of the las er installation.