METHOD FOR STRENGTHENING SURFACE OF SLIDE BEARING OF DRILLING BIT Russian patent published in 1995 - IPC

FIELD: drilling bits. SUBSTANCE: borating is carried out in two stages: first at 840-860 C, then the temperature is increased to 900-920 C for a preset period. This forms a multilayer structure of the coating wherein iron hemoboride and boron cementite with relatively penetrating teeth are positioned on the cemented layer. Borating is carried out with a mixture composed of, wt. -% boron carbide, 40-70; modifying mixture, 10-30; the balance consists of equal parts of graphite or aluminium oxide, or aluminium oxide and iron powder, or iron powder and graphite. EFFECT: high hardness and wear resistance of strong and plastic base. 2 cl, 5 dwg