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Verschleißschutz durch Laserbeschichten mit wolframkarbidverstärkten Hartlegierungen

: Nowotny, S.; Techel, A.

TU Bergakademie Freiberg:
MEFORM '95. Umformwerkzeuge - Beanspruchung und Verschleiß. Tagungsband
Freiberg, 1995
Freiberger Umformtechnisches Seminar (MEFORM) <1995, Freiberg>
Fraunhofer IWS ()
cladding; composite; Hartstoffschicht; laser; metal forming tool; Oberflächenbearbeitung; Verschleiß; wear

Highly stressed metal forming tools require surface layers with high resistance to abrasive wear, impact and thermoshock. A new, useful technique for producing protection layers for complex load conditions is laser cladding with carbide reinforced hard alloys. In the present work, powder mixtures of WC/Co agglomerated carbide and WC/W2C melt carbide, combined with a self fluxing Ni-alloy, are clad onto tool steels. By using optimised process parameters, a repeatable composite coating free of pores, cracks and with low iron dissolution can be reached. The typical structure shows a homogeneous distribution of coarse, non-melted carbide particles within the metallic matrix alloy. The carbide content is up to 50 volume percent. Large-scale investigations on the wear behaviour show that the wear resistance of laser clad coatings comes close to that of classical, sintered hard metal WC/Co. In contrast to sintered hard metal, these coatings have a higher toughness, which provides good perform ance also under conditions including fatigue or impact. The layers are characterised by a strong metallurgical bonding to the substrate. Examples of forming dies, laser clad with carbide containing composites, are shown in the paper.