Sintered composite body comprising cemented carbide and cbn grains

Abstract

A sintered composite body of cemented carbide and cBN grains, wherein the cBN grains are dispersed in a cemented carbide matrix. The body further includes a cBN depleted zone extending 50-400 μm from the surface of the body towards the core thereof. The mean cBN grain size outside the depleted zone is 1-20 μm and the cBN content outside the depleted zone is 0.3-4 wt %.

1 . A sintered composite body comprising cemented carbide and cBN grains, wherein the cBN grains are dispersed in a cemented carbide matrix, wherein said body comprises a cBN depleted zone having a gradient depth of 50-400 μm extending from a surface of the body towards a core of the body and a mean cBN grain size outside the depleted zone is 1-20 μm and a cBN content outside the depleted zone is 0.3-4 wt %, the depleted zone being formed by a method comprising the steps of sintering the body at a temperature of 1250-1360° C., in a gas selected from the group of Ar or N 2  and holding the sintering temperature for a dwelling time of 10-80 minutes. 
     
     
         2 . The sintered composite body according to  claim 1 , wherein the cBN depleted zone gradient depth is 50-200 μm. 
     
     
         3 . The sintered composite body according to  claim 1 , wherein the cBN depleted zone gradient depth is 200-400 μm. 
     
     
         4 . The sintered composite body according to  claim 1 , wherein the cemented carbide comprises 6-16 wt % binder phase. 
     
     
         5 . The sintered composite body according to  claim 4 , wherein the binder phase comprises Co. 
     
     
         6 . The sintered composite body according to  claim 4 , wherein the cemented carbide comprises 10-14 wt % Co. 
     
     
         7 . The sintered composite body according to  claim 1 , wherein the cemented carbide comprises WC. 
     
     
         8 . The sintered composite body according to  claim 7 , wherein the cemented carbide comprises 80-94 wt % WC. 
     
     
         9 . The sintered composite body according to  claim 7 , wherein the mean WC grain size is 0.5-8 μm. 
     
     
         10 . A wear part of a sintered composite body comprising cemented carbide and cBN grains, wherein the cBN grains are dispersed in a cemented carbide matrix, wherein said body comprises a cBN depleted zone having a gradient depth of 50-400 μm extending from a surface of the body towards a core of the body and a mean cBN grain size outside the depleted zone is 1-20 μm and a cBN content outside the depleted zone is 0.3-4 wt %, the depleted zone being formed by a method comprising the steps of sintering the body at a temperature of 1250-1360° C., in a gas selected from the group of Ar or N 2  and holding the sintering temperature for a dwelling time of 10-80 minutes. 
     
     
         11 . A saw tooth of a sintered composite body comprising cemented carbide and cBN grains, wherein the cBN grains are dispersed in a cemented carbide matrix, wherein said body comprises a cBN depleted zone having a gradient depth of 50-400 μm extending from a surface of the body towards a core of the body and a mean cBN grain size outside the depleted zone is 1-20 μm and a cBN content outside the depleted zone is 0.3-4 wt %, the depleted zone being formed by a method comprising the steps of sintering the body at a temperature of 1250-1360° C., in a gas selected from the group of Ar or N 2  and holding the sintering temperature for a dwelling time of 10-80 minutes. 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . The sintered composite body of  claim 1 , wherein the sintering temperature is 1300-1360° C.