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Lecture

Unterstanding the degradation behaviour of Fused Tungsten Carbide in GMAW welded Ni-WC overlays

Tuesday (21.02.2017)
15:15 - 15:40 Rohrersaal
Part of:


The application of fused tungsten carbides (FTC) embedded in a Ni-base alloy plays a very important role to improve the wear resistance of tooling equipment in the mining industry. However, FTC are thermally instable and tend to dilute in case of too high energy inputs during welding. In this context, the number of parameters affecting the dilution is versatile and not completely understood yet, whereby a profound understanding is necessary to improve both process characteristics and overlay properties.


Based on a widely used welding process (Gas Metal Arc Welding), an experimental setup was realized in order to determine the respective influence of process parameters on the FTC dissolution behaviour. It could be found out, that the Fe-content of the weld (based on the dilution rate) has a dominant influence on the degredation behaviour at a value above 15 %. In contrast, the effect of the weld pool size is comparatively small. A dominant influence could be attributed to the welding arc and the mode of droplet transfer. Thereby, it could be found out, that the degradation of FTC using a short arc is approximately twice lower compared to a spray arc.

Furthermore, new metallurgical findings will be presented with respect to the dissolution mechanism of FTC.

 

Speaker:
Karsten Günther
Technical University of Ilmenau
Additional Authors:
  • Prof. Dr. Jean Pierre Bergmann
    Technical University Ilmenau