Patent ID: 7150897
Filing Date: 2006-12-19
Classification: B22F,C22C,C23C,Y10T

Abstract:
1. Method for producing a cemented carbide body comprising decarburizing a cemented carbide body containing from about 3 to about 12 weight % binder phase in H 2 +H 2 O or H 2 +CO 2 gas atmosphere at a temperature of from about 900 to about 1290° C., for from about 1 to about 10 h to form an eta phase containing surface zone and then heat treating the body at a heat treating temperature of from about 1350 to about 1450° C., for 10 min–10 h, in a neutral gas atmosphere or vacuum to completely retransform the eta phase or other phases formed during decarburization to WC+Co phase and form a body with a carbon content below the saturation point with an about 5 to about 100 μm thick surface zone having an increased WC grain size relative to a grain size of WC in an interior region of the body, the increased WC grain size present within the entire thickness of the surface zone.