DRILLING BIT INSERT Russian patent published in 2021 - IPC C04B35/56 C22C29/08 E21B10/08 

FIELD: machinery.

SUBSTANCE: drilling bit insert made of hard alloy containing hard tungsten carbide (WC) constituents in a binder phase containing Co, wherein the alloy in the innermost part of the insert contains 4 to 18 wt.% Co with the remainder of WC and unavoidable impurities and contains Cr in such an amount that the Cr/Co weight ratio is between 0.04 and 0.19. The difference between the hardness at a depth of 0.3 mm at any point on the surface of the drilling bit insert and the hardness of the body volume of the drilling bit insert is no less than 40 HV3.

EFFECT: increased corrosion resistance and reduced wear in wet drilling.

13 cl, 10 ex, 22 tbl, 16 dwg