Performance optimization of diamond-impregnated bit for extra-hard and strong-abrasive rocks

On account of the phenomenon that the drilling footage is low when diamond bit is used to drill hard compact abrasive rocks, SiC particles are added into matrix as abrasion-weakening particles. By using lab drilling and orthogonal test, the performance of bit was optimized in the aspects of diamond size, concentration of abrasion-weakening particles, hardness of matrix. The influence of drilling technological parameters on drilling efficiency was discussed. The results showed that adding abrasion-weakening particles with proper texture into bit matrix can enhance drilling efficiency and avoid bit slipping; the optimal designing scheme of the test was hardness HRC 25, diamond particle size 40/50 mesh, diamond concentration 55%, abrasion-weakening particle concentration 30%; at the same spindle speed, axial compressive force should not exceed 3.5 MPa. Under the same axial compressive force, the apropriate spindle speed isd is 750 to 850 r/min.