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Laser cladding of hard particles rich alloys

Laserauftragschweißen von hartstoffreichen Legierungen

International Congress on Applications of Lasers and Electro Optics (ICALEO) <1992, Orlando/Fla.>
Conference Proceedings
Fraunhofer IWS ()
composite powders; Hartstoff; heterogeneous alloy; laser; laser cladding; laser powder cladding; laser-Pulver-Beschichten; laserauftragschweißen; laserbeschichten

The protection against abrasive wear requires high hardness of the load surfaces. In many cases transformation hardening of steels is unsufficient, and a hardfacing process is necessary. For coatings produced in this manner, wear is governd by the content of hard intermetallic or ceramic phases and their grain size. The abrasive wear resistance is higher for large content and size of hard phases. Also the hard phases must be harder than the abrasive particles. Laser cladding with continuous powder feed into the melting pool permits the deposition of heterogeneous alloys with uniformly distributed nonmelted or nearly nonmelted hard particles in a metallic matrix. The present investigation shows that hard particle contents up to 45 percents of volume can be reached experimentally. On the basis of the material systems WC/Co-NiCrBSi, WC/Co-Stellite 21, WC/NI-Stellite 21, WC(melt carbide)-Stellite 21 and TiC-steel, metallurgical aspects of matrix embrittlement due to the hard particle disso lution are dicussed. The technological conditions for a low carbide dissolution are specified and some wear testing results are presented.