Herstellung hartmetallähnlicher Verschleißschutzschichten durch Laserauftragsschweißen von Hartstoff-Hartlegierungs-Pulvergemischen

Protective layers exhibiting abrasive wear resistance similare to that of conventional WC/Co hard metal can be repeatably produced by laser cladding using powder mixtures consisting of hard material and binder components. As an advantage compared to sintered hard metals, the claddings can be immediately applied to the load bearing faces. Strong bonding to the base material can be achieved. Unlike sintered hard metal, the claddings show maximum wear resistence with non- dissolved hard material contents as low as 40-50 percent. Thus the claddings are rather ductile, which implies higher resistence to fatigue, impact, and thermal shock. The optimized WC/Co-NiBSi system performs best results with respect to wear, flaws, and cost. Fused tungsten carbide exhibits equivalent wear resistance but the layers may be flawed. Claddings with Stellite 21 binder show minimum wear at contents of 35 vol percent hard material, though cracking and debonding spoil the over-all performance. Based on solid k nowledge derived from work on processing and materials technology, the laser cladding technique described here is ready for industrial application.