Research On Positioned Diamond Bionic Coring Bit

In order to improve the drilling efficiency and working life-span of impregnateddiamond bit, the bionics theory was introduced. With the development of materialindustry and diamond tools industry, the uniform distribution technology of diamondis greatly used in the grinding tool. This method not only increases the diamondutilization efficiency and prolongs the working life-span of the diamond tools, butalso saves the usage of diamond grains and reduces the cost in manufacturing.This thesis chooses “The study of positioned diamond bionic coring bit” asresearch topic, especially for the problems, such as the uneven distribution ofdiamond grains and short life-span of drill bit. This research combines thecharacteristics of bionic diamond bit and diamond positioning arrangementtechnology to manufacture a high efficient and long-life diamond bit, the drill bitperforms well in wear resistance characteristics and avoiding the abnormal wear ofdiamond. The research contents include the choice of diamond, matrix formulationresearch; manufacturing of diamond positioned mould and bionic drill bitmanufacturing processes. The results obtained from the research are as follows:1. The geometry morphology of mole cricket toe is chosen as the biologicalprototype of positioned diamond bionic coring bit. Through copying this biologicalmorphology, the bionic wedge groove is designed, and this method is proved to befeasible after tests. The performance of positioned diamond bionic coring bit is betterthan that of bionic diamond bit and common bit. That’s because the positioneddiamonds make the groove array in good order and avoid the aggregation or blank of diamonds in the drill bit.2、Static strength results show that the difference in static strength betweenimported diamonds and domestic diamonds is very small. To some extent, the staticstrength of domestic diamonds is higher than that of imported one; Under the vacuumcondition, in1200℃, the carbonization of diamonds occur only among thediamonds with internal defects; On the same size of diamonds, static strength ofdiamonds coated with Titanium is higher than common diamonds, and in hightemperature the diamonds coated with Titanium also have good antioxidant capacity.The thermal test results show that under the condition of N2as a separate gas,heat-resistant temperature of imported diamonds is1050℃, while that of domesticdiamond is1040℃.So it is easy to see that the thermal stability of the importeddiamonds is higher than the domestic one only by10℃. Magnetic test resultsshow that translation phenomenon of magnetic hysteresis loop happen in two types ofdiamonds. In conclusion, during the drilling process, diamond bits withstand not onlythe temperature, but also the impact and friction. Therefore it is necessary to considerthe factors of diamond static strength, thermal stability and magnetism to evaluate theoverall performance of the diamond.3、In this study, for getting better properties of WC matrix composites, theRockwell Hardness and bending strength, etc. Of30WC matrix composites, preparedby10different formulas, were tested. These samples were manufactured by thevacuum hot-pressing sintering process using intermediate-frequency furnace under theconditions of13MPa (Sintering pressure), the heating time of6min and the holdingtime of5min. The influence of WC, ZQSn663copper, Mn, Co, and Ni on thehardness and bending strength properties of matrix was investigated by data analysis.The results indicated that the content of WC is the major factor to influence thehardness and bending strength of matrix. Internal logic existed between the matrix’shardness and bending strength. The matrix with high hardness always has highstrength. To get excellent performance of the matrix, the proportion of elements by mass should be controlled in formula: w(WC）<59.1%, w(ZQSn663)>25%,3%<w(Ni)<6.5%,0.9%<w(Co)<3.5%, w(WC—ZQSn663)<20%.4、The rock fragmentation mechanisms of bionic impregnated diamond bit andpositioned diamond bionic bit are analyzed and summarized. Software LS-DYNA isused to analyze Φ135.5/72mm bionic impregnated diamond bit and commonimpregnated diamond bit with nonlinear analysis. The simulation result shows thatunder the same WOB (weight on bit), rotary speed, rock conditions and simulationtime, compared with common bit, bionic groove diamond drill bit and bionic pitdiamond drill bit make the rock suffer tensile stress, drill deeper than conventionaldrill bit, and crush the rock in large degree.5、According to the manufacturing processes of positioned diamond bionic bit,three new coring bits are designed and manufactured. By testing the drill-ability ofgranite, Ⅳ Formula is selected, and this formula would make the hardness of matrixbody reach38.6. The grain size of diamonds is30/35from imported diamonds. Thesintering parameters are listed as follows: temperature is970℃, and the temperaturerising gradient is uniform. Sintering pressure is14Mpa, and heat preservation time is8~10min. Experimental results show that the positioned diamond bionic bitperforms well in the low WOB and small torque drilling conditions. When the WOBis2000N, the ROP (rate of penetration) of positioned diamond bionic bit is1.433times as fast as bionic diamond bit, and it is3.160times as fast as common diamondbit. The ROP of bionic diamond bit is2.206times as fast as common bit.