How can I improve the wetting of brazing filler metals onto cemented tungsten carbide?
The cemented carbide will be more easily wetted by the molten brazing filler metal if the surface is ground shortly before brazing then degreased and kept clean before applying flux. The degree of wetting of brazing filler metal onto a cemented tungsten carbide piece will depend on its composition. Cemented tungsten carbides with small additions of titanium or tantalum carbide are more difficult to wet than standard carbides. Wetting can be improved by the use of brazing filler metals containing nickel or manganese (e.g. Argo-braze 49H) and special boron modified fluxes such as Tenacity No.6 Flux Powder or Paste. Plating or coating the carbide with an easy to wet metal such as copper or nickel can also help overcome this problem. In general when brazing cemented tungsten carbide a heating pattern should be employed which brings both components to brazing temperature at the same time. Care should be taken to avoid overheating the cemented tungsten carbide component as this will increase
