Fine grained cemented carbide with refined structure

摘要

The present invention relates to a fine grained WC-Co cemented carbide. By adding an extremely small amount of Ti, V, Zr, Ta or Nb alone or in combinations, a grain refined cemented carbide structure with less abnormal WC-grains has been obtained.

主权项

1. WC-Co cemented carbide comprising a composition of from about 3 to about 15 wt-% Co and Cr such that the Cr/Co-ratio by weight is from about 0.05 to about 0.15 and balance WC and in addition:
one of the following additional elements V, Nb, Zr, or Ta then with a grain size of WC of from about 0.1 to about 2.0 μm; or mixtures of at least two of Ti, V, Nb, Zr, or Ta, excluding a mixture consisting of Ti and Ta, then with a grain size of the WC of more than about 0.3 up to about 2.0 μm, the ratio of
Me/Co=(at-% Ti+at-% V+at-% Nb+at-% Zr+at-% Ta)/at-% Co  is lower than or equal to about 0.014-(CW_Cr)*0.008 and higher than about 0.0005, with a CW_Cr ratio of from about 0.79 to about 0.95, with
CW_Cr=(magnetic-% Co+1.13*wt % Cr)/wt % Co  where magnetic-% Co is the weight percentage of magnetic Co and wt-% Co is the weight percentage of Co in the cemented carbide.