Cemented carbide insert for mining or cutting applications comprising gamma phase carbide

Abstract

A sintered cemented carbide insert for mining or cutting applications includes a mean WC grain size of between 0.8-18 μm, a binder phase in a weight between 4-18 wt %, a gamma phase with the cubic gamma phase precursors in a weight of between 0.8-10 wt %, and any unavoidable impurities and a balance of WC. A difference between the hardness at any point 0.3 mm from the surface of the insert and the hardness of the bulk is at least 25 HV3, wherein hardness is measured according to ISO EN6507. A method of producing the cemented carbide is also provided.

1 . A sintered cemented carbide insert for mining or cutting applications comprising:
 a mean WC grain size of between 0.8-18 μm;   a binder phase in a weight between 4-18 wt %;   gamma phase with the cubic gamma phase precursors in a weight of between 0.8-10 wt %; and   any unavoidable impurities and a balance of WC, wherein a difference between a hardness at any point 0.3 mm from a surface of the insert and a hardness of a bulk of the insert is at least 25 HV3 when measured according to ISO EN6507 3:2005.   
     
     
         2 . The insert according to  claim 1 , wherein the binder phase includes at least 80 wt % of one or more of cobalt, nickel, iron or a combination thereof. 
     
     
         3 . The insert according to  claim 1 , wherein the cubic gamma phase precursors is tantalum carbide or niobium carbide or a mixture thereof. 
     
     
         4 . The insert according to  claim 1 , wherein the cemented carbide also includes Cr in such an amount that a mass ratio Cr/Co in the bulk is 0.04-0.19. 
     
     
         5 . The insert according to  claim 1 , wherein the cemented carbide includes M 7 C 3  carbides and/or M 23 C 6  carbides and wherein a ratio vol % (M 7 C 3  carbides and/or M 23 C 6  carbide)/vol % Co is between 0.01 to 0.5. 
     
     
         6 . The insert according to  claim 1 , wherein a delta K1C fracture toughness at 0.5 mm below the surface compared to a K1C in the bulk is at least 1.5 MPa*m 0.5  higher measured according to ISO/DIS 28079. 
     
     
         7 . A rock drill bit body comprising one or more mounted cemented carbide inserts according to  claim 1 . 
     
     
         8 . A method of producing a cemented carbide insert according to  claim 1 , comprising the steps of:
 providing a green cemented carbide insert comprising between 0.8-10 wt % cubic carbides and or carbonitrides and or nitrides, between 4-18 wt % binder, any unavoidable impurities and a balance of WC hard phase;   sintering the green carbide mining insert to form a sintered cemented carbide insert; and   subjecting the sintered cemented carbide insert to a high energy post-treatment process.   
     
     
         9 . The method according to  claim 8 , wherein the high energy post-treatment is high energy tumbling. 
     
     
         10 . The method according to  claim 8 , wherein the high energy post-treatment is conducted at an elevated temperature of or above 100° C. 
     
     
         11 . The method according to  claim 8 , wherein the high energy post-treatment is conducted by a bi-directional shaking process. 
     
     
         12 . The method according to  claim 8 , wherein the bi-directional shaking process has a main movement is in a vertical direction and a minor movement is in a horizontal direction. 
     
     
         13 . The method according to  claim 8 , wherein the treatment is conducted at between 400-700 rpm for 5-30 min.