Research On No-Hardphase-Matrix Impregnated Diamond Bit With Bionic Abnormal Shape

Resources are the material basis for the long-term and stable development of the national economy.With the depletion of shallow resources and the developing of deep drilling,deep exploration and development is imperative.However,how to improve the efficiency and reduce the cost of deep drilling is a strict requirement for the drilling tools quality and performance.Bit is the core in the drilling technology and drilling process,its drilling rate and working life directly affects the efficiency and cost of deep drilling.However,the drilling speed and working life of the bit are often difficult to improve simultaneously.In order to improve the drilling rate and working life of bit for drilling in hard rock,especially in hard-slip rock,this thesis has designed a new type bionic bit based on the bionic theory.The main research work and related conclusions of the thesis are as follows:(1)In view of the rock characteristics of drilling hard-slip formation,the bionic structure and the performance requirements of bit,an idea of no-hardphase matrix for impregnated diamond bit is proposed.The matrix was mainly including iron,nickel and copper alloy without W,WC,TiC and other refractory high hardness metal or alloy.The properties of the matrix were improved by adding boron,which the addition amount was optimized.In conclusion,the boron-added no-hardphase matrix for impregnated diamond bit alleviated the problem of thermal damage,oxidation and carbonization of diamond,reduced the corrosion,improved the bonding force between diamond and matrix.In addition,it greatly improved the wear resistance of no-hardphase matrix for impregnated diamond bit.(2)In view of the characteristics of drilling hard-slip rock,the structure requirements of bit,the bionic abnormal shape cutting unit was designed based on Pangloin jaw as bionic prototype.The bionic jaw model was conducted according to the anlysis the shape,structure and function of the pangolin jaw,and the bionic bit was conducted.Through the mechanical calculation was used to optimize the height ratio of the column tooth and the aspect ratio of the inner—outer ladder drill teeth.ANSYS was used to simulate the changes of the rock stress caused by the static load for comparing the bionic diamond bit and conventional step drill bit.In conclusion,the height ratio of the column tooth is related to the poisson ratio and the aspect ratio is related to the friction coefficient.In addition,bionic bit has a bigger stress than that of common ladder bit.(3)The bionic abnormal shape impregnated diamond bits were fabricated using graphited die and clay die by pressureless impregnation sintering process,which avoided the limitation of the bit structure and height of the bit by hot pressing.In conclusion,the pressureless impregnation process fabricated bits have a good structure and performances.(4)In drilling test,the drilling speed was increased by 20%~97.5% and the drill life increased by 1~2 times.The rock fragmentation mechanism of bionic bit was analyzed.Boron-added no-hardphase matrix protected the diamond's strength and cutting capacity,its wear resistance matched the diamond wear,improved the diamond's self-sharpening ability for improving the diamond work efficiency.The bionic structure changed the rock state,and increased the rock free surface,the high work layer extended the bit life,the self-regenerated structure to achieved the bit self-sharpening.So the no-hardphase-matrix impregnated diamond bit with bionic abnormal shape has fast drilling speed and long working life.The drilling rate and working life of the new no-hardphase-matrix impregnated diamond bit with bionic abnormal shape are increased synchronously in drilling tests.It is significant to the subsequent bionic drill design and optimization.