Iron-based impregnated diamond drill bit for hard rock drilling and its preparation method

Abstract

The application relates to the field of diamond drill bits for hard rock drilling, and particularly discloses an iron-based impregnated diamond hole drill for hard rock drilling capable of dry operation and a preparation method thereof. The hole drill comprises a drill bit steel body, diamonds and a matrix, the diamonds are impregnated on the matrix, and the matrix comprises the following components: Fe powder, Cu powder, nano cratering powder, a Ni-Cr alloy, a powder lubricant, rare earth Pr, rare earth Ce, nano NbC and carbon nanotubes; the preparation method comprises the following steps: premixing, mixing, cratering treatment on the surface of the diamonds, hot-pressing sintering and drill bit etching and friction increasing treatment. The diamond hole drill can be used for hard rock drilling operation, has the advantages of dry drilling, high wear resistance, and the diamonds are not easy to fall off; in addition, the preparation method avoids the agglomeration of nanoscale materials, increases the surface area of the diamonds, thereby increasing the tightness of the diamonds and the matrix, and enables the diamonds to quickly form a cutting edge at the initial stage of the drilling operation, thereby increasing the working efficiency of the hole drill.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of diamond drill bits for hard rock drilling, more particularly, it relates to an iron-based impregnated diamond drill bit for hard rock drilling and a preparation method thereof. BACKGROUND

[0002] With the rapid development of science and technology and economy, the demand for oil and gas and mineral resources is increasing, and the fossil energy on the surface of the earth has been difficult to maintain the development of human beings, so deep well drilling and hard rock drilling have gradually become the focus of development in various countries. As one of the most commonly used drill bits in hard rock drilling, impregnated diamond drill bits are widely used in drilling engineering such as geological exploration and mineral exploration.

[0003] The impregnated diamond drill bit is composed of a matrix, a drill bit steel body and diamonds. The drill bit steel body serves as a structural support, the matrix is attached to the bottom of the drill bit steel body and is used to embed the diamonds. The matrix is mainly composed of some metal powder mixture. During drilling, the matrix is worn by the rock, and the diamonds in the matrix are exposed and ground the rock. As the diamonds are continuously worn, the powder is also continuously worn and consumed, and the gradually exposed diamonds lose the embedding effect of the powder, and finally fall off together with the powder and expose new diamonds to continue drilling the rock formation. In the traditional technology, the commonly used drill bit matrix system is divided into Co-based, WC-based and Fe-based, each of which has its own advantages. However, the Co-based matrix is expensive, the WC-based matrix has poor self-sharpening property, and the application range is small, so the Fe-based matrix gradually becomes the most commonly used matrix.

[0004] When the rock formation is hard and weakly abrasive, the drilling efficiency of the diamond drill bit is low, and the drill bit is also prone to slipping. In order to increase the drilling efficiency of the drill bit on hard and weakly abrasive rock formations, a soft phase metal element and its alloy are added to the matrix in related technology to reduce the interfacial bonding strength of the matrix, so that the matrix is more easily worn to accelerate the exposure of the diamonds.

[0005] A hard and slippery formation drilling iron-based impregnated diamond drill bit is disclosed in Chinese patent CN102828696B. The matrix of the drill bit is composed of 70% iron powder, 12% zinc powder, 15% bronze powder and 2% nickel powder by mass percentage, and is prepared by mixing, charging, drying, hot pressing and sintering. The soft phase elements such as Cu and Zn in the matrix reduce the interfacial strength of the iron-based matrix, making it more easily worn, increasing the exposure rate of the diamonds, and enabling the drill bit to be used for drilling hard and weakly abrasive rock formations.

[0006] According to the related technology in the above, the inventors believe that there are the following problems:

[0007] Firstly, the interface bonding strength of the matrix is reduced, which also reduces the ability of embedding the diamond, thereby increasing the probability of the diamond falling off. In actual drilling operation, about one third of the volume of the diamond will fall off, and the diamond falling off too early will be worn together with the rock, thereby seriously increasing the wear of the drill bit.

[0008] Secondly, the iron powder, bronze powder and zinc powder as the main components of the matrix are easy to crystallize and gather at high temperature when the matrix is sintered, which makes the matrix unevenly heated, and further makes the diamond not tightly combined with the matrix, thereby reducing the tolerance and continuous operation ability of the drill bit.

[0009] Thirdly, the iron powder in the matrix will graphitize the diamond when sintered, thereby reducing the drilling performance of the diamond.

[0010] Fourthly, when drilling hard rock, a large amount of heat is generated by the high-speed friction between the drill bit and the hard rock. In order to increase the service life of the drill bit, more cooling water needs to be added to cool the drill bit, which is time-consuming and laborious. SUMMARY

[0011] In order to improve the problems of high loss, short service life and poor tolerance of the drill bit when drilling hard rock in the related art, the present application provides an iron-based impregnated diamond hole drill for hard rock drilling which can be dry operated and a preparation method thereof.

[0012] In a first aspect, the present application provides an iron-based impregnated diamond hole drill for hard rock drilling which can be dry operated, which adopts the following technical solution:

[0013] An iron-based impregnated diamond hole drill for hard rock drilling which can be dry operated, comprising a drill bit steel body and a diamond, further comprising a matrix, wherein the diamond is impregnated in the matrix; the matrix comprises the following components in mass percentage:

[0014] Fe powder 61.3% to 72.82% Cu powder 12% to 15% nanometer cratering powder 6% to 8%

[0015] Ni-Cr alloy 4% to 6% powder lubricant 2 to 5% rare earth Pr 0.7% to 1%

[0016] Rare earth Ce 0.4% to 0.6% nanometer NbC 2% to 3% carbon nanotube 0.08% to 0.1%.

[0017] By adopting the above technical solution, the Fe powder is the main structural basis of the matrix, which is low in cost and rich in resources, and has no obvious difference from the Fe powder in the related art; the Fe powder will promote the graphitization of the diamond in the sintering overlayer, therefore, the present application adds Ni-Cr alloy in the matrix components.

[0018] The Cr element in the Ni-Cr alloy can form a carbide layer on the surface of the diamond, reducing the possibility of Fe powder contacting the diamond and causing the diamond to graphitize; however, the addition of Cr also reduces the impact toughness of the drill bit;

[0019] The rare earth Pr can increase the impact toughness of the drill bit, but the diffusion coefficient of the rare earth Pr in Fe is small, and it is difficult to tightly combine with each material of the matrix;

[0020] The Ni element in the Ni-Cr alloy can cause the three elements of Fe, Ni, and Cr to form vacancies in the matrix due to the difference in the diffusion coefficient, and the rare earth Pr can fill in the vacancies, increasing the bonding degree of the rare earth Pr with each material of the matrix, thereby increasing the impact toughness of the diamond;

[0021] The Ni and Cr elements have a large difference in the thermal expansion coefficient with the diamond and the drill steel body, and in actual drilling operations, due to the difference in the thermal expansion coefficient of Ni and Cr, cracks can be generated in the matrix due to uneven heating;

[0022] The rare earth Ce can cause the internal part of the matrix to be uniformly heated, reducing the possibility of cracks in the matrix due to the difference in the thermal expansion coefficient of Ni and Cr, and also reducing the problem of uneven heating of the matrix due to the crystallization of Fe and Cu during sintering, effectively reducing the generation of cracks in the internal part of the matrix;

[0023] The powder lubricant can make the matrix combination more tightly, reduce the crack structure in the matrix, and improve the resistance and continuous operation ability of the matrix; however, due to the improvement of wear resistance, the matrix is difficult to fall off, and the diamond is difficult to come out;

[0024] The nano-pitted powder can make the surface of the drill bit uneven, increase the friction area between the matrix and the rock stratum, so that the diamond can quickly come out at the initial stage of the drilling operation;

[0025] During drilling operation, the drill bit rotates at high speed, and long-term high-temperature operation can reduce the performance of the drill bit, therefore, the application adds Cu powder in the matrix component; Cu has excellent thermal conductivity, which can quickly conduct the heat generated during drilling; at the same time, the rare earth Ce cooperates with Cu to uniformly disperse the heat of each part of the matrix during the heat conduction, and the matrix will not fall off due to uneven heating, therefore, the drill bit of the application can adapt to dry drilling operation, and the amount of cooling water can be reduced during drilling operation, or even no cooling water is used;

[0026] However, Cu is a soft phase in the matrix, which can reduce the interfacial strength of the matrix, thereby causing the diamond to fall off too early; therefore, the application adds nano-NbC and carbon nanotubes in the matrix component, which cooperate with each other to increase the proportion of hard phases in the matrix;

[0027] Meanwhile, Fe powder and Cu powder are easy to crystallize and gather when hot-pressed and sintered, thus reducing the tightness of the matrix and the diamond. The powder lubricant can form a lubricating film on the surface of Fe and Cu atoms, reducing the probability of crystal growth. Meanwhile, the rare earth Ce can also make the matrix evenly heated when sintered, thus optimizing the problem of Fe and Cu crystallization.

[0028] In summary, the Fe powder, Cu powder, nano-pit powder, Ni-Cr alloy, powder lubricant, rare earth Pr, rare earth Ce, nano-NbC, and carbon nanotube in the application cooperate with each other to optimize the graphitization of Fe powder on diamond, the tightness of the matrix when Fe-Cu is used as the main material, and the need for water cooling of the drill bit. Meanwhile, the application discards the method of reducing the interface strength of the matrix, and uses the cooperation of various components in the matrix to make the diamond and the matrix tightly combined, ensuring that the diamond is fully worn before falling off. This not only makes the hole drill suitable for hard rock drilling operations, but also greatly increases the service life of the drill bit, and optimizes various problems in related technologies.

[0029] Preferably, the matrix comprises the following components in mass percentage:

[0030] Fe powder 66.11% to 69.11% Cu powder 13% to 14% Nano-pit powder 7%

[0031] Ni-Cr alloy 4% to 5% Powder lubricant 3 to 4% Rare earth Pr 0.8%

[0032] Rare earth Ce 0.5% Nano-NbC 2.5% Carbon nanotube 0.09%.

[0033] By using the above technical solution, when the components in the matrix are in the above ratio, the hole drill prepared has more excellent heat dissipation, resistance, wear resistance, etc., and a longer service life.

[0034] Preferably, the particle size of the diamond is 40 to 45 mesh, and the concentration is 50%vol.

[0035] By using the above technical solution, too large particle size and too high concentration of the diamond will reduce the embedding capacity of the matrix, thus causing the diamond to fall off too early. Too small particle size or too small concentration of the diamond will cause insufficient contact between the rock stratum and the diamond, thus reducing the rock breaking efficiency of the hole drill. When the particle size and concentration of the diamond meet the above conditions, the diamond can be fully embedded by the matrix, and the hole drill has high rock breaking capacity.

[0036] Preferably, the nano-pit powder is selected from nano-alumina powder.

[0037] By adopting the technical scheme, the nano-alumina powder has stable physical properties and relatively active chemical properties; during etching treatment, the nano-alumina on the surface of the hole drill is etched and leaves small pits on the surface of the hole drill, so that the surface of the hole drill is uneven, the surface area of the hole drill is increased, the friction area between the matrix and the rock stratum is increased, and the diamond is smoothly out of the blade; meanwhile, the nano-alumina powder in the matrix can be filled in the matrix as a hard phase, the interface strength of the matrix is increased, and the possibility of the diamond falling off too early is reduced.

[0038] Preferably, the powder lubricant is WS2 or CaF2.

[0039] By adopting the technical scheme, the WS2 or CaF2 can form a lubricating film on the surface of the remaining components of the matrix, especially Ni and Cr, the probability of the matrix cracking due to the difference in the thermal expansion coefficients of Ni and Cr is reduced; meanwhile, the lubricating film can prevent the adhesion and agglomeration of the matrix components, the matrix components are uniformly dispersed, the compactness of the matrix is increased, and the resistance and the continuous operation capacity of the drill bit are improved.

[0040] In the second aspect, the application provides a preparation method of the iron-based impregnated diamond hole drill for hard rock drilling, which adopts the following technical scheme:

[0041] The preparation method of the iron-based impregnated diamond hole drill for hard rock drilling includes the following steps:

[0042] (1) Pre-mixture

[0043] Fe powder, Cu powder, Ni-Cr alloy, rare earth Pr, and rare earth Ce are weighed according to the mass percentage and mixed into coarse materials;

[0044] (2) Mixing

[0045] Nano-pitting powder, nano-NbC, and carbon nanotubes are weighed according to the mass percentage, mixed with anhydrous ethanol, and then ultrasonically dispersed to obtain a nano-mixture; a powder lubricant is weighed according to the mass percentage, and the nano-mixture, the coarse materials, and the powder lubricant are mixed and ball milled to obtain a matrix mixture;

[0046] (3) Diamond surface pitting treatment

[0047] Diamonds with appropriate concentration and particle size are selected, and the diamonds are subjected to pitting treatment by using a surface treatment liquid to obtain pitted diamonds;

[0048] (4) Hot-pressing sintering

[0049] Mix the matrix material with the diamond after cratering treatment in glycerol-absolute alcohol environment, then lay it in graphite mold; put the drill steel body, maintain the temperature at 960-1000 DEG C, the pressure at 14.5-15.5 MPa, and hot-press sinter for 5-10 min; cool and form to obtain the drill rough product;

[0050] (5) Drill etching abrasion increasing treatment

[0051] Use etching liquid to wet the bottom matrix part of the drill rough product for 5-10 min, clean and dry to obtain the dryable hard rock drilling iron-based impregnated diamond drill.

[0052] By adopting the technical scheme, the preparation method has the following advantages:

[0053] First, the method of the application first ultrasonically treats the nanometer cratering powder, nanometer NbC, carbon nanotube and other nanometer materials in the matrix component before mixing, which reduces the possibility of agglomeration of the nanometer materials, so that the prepared matrix structure is uniform and the performance is stable;

[0054] Second, the application performs cratering treatment on the surface of the diamond before hot-press sintering, so that the surface area of the diamond is increased, thereby increasing the bonding strength between the diamond and the matrix and optimizing the technical problem of easy falling of the diamond in the related art;

[0055] Third, the application performs etching abrasion increasing treatment on the surface of the drill after sintering and forming, so that the diamond can quickly sharpen at the initial stage of the drilling operation, thereby increasing the working efficiency of the drill.

[0056] Preferably, the surface treatment liquid used in step (3) is selected from one or more of perchloric acid, nitric acid and sulfuric acid.

[0057] By adopting the technical scheme, perchloric acid, nitric acid and sulfuric acid are all strong oxidizing acids, which can first maintain the acidic environment required for the surface treatment of the diamond, and secondly react with C atoms on the surface of the diamond to form an oxide film. These C elements consumed by the reaction leave nanoscale pits on the surface of the diamond. When the diamond is mixed and sintered with the matrix, the components in the matrix will be more closely combined with the diamond under the action of these nanoscale pits, so that the diamond will not fall off until it is fully worn by the rock stratum.

[0058] Preferably, the etching liquid used in step (5) is selected from one or more of alkali metal hydroxides or alkaline earth metal hydroxides.

[0059] By adopting the technical scheme, the alkali metal hydroxide and the alkali earth metal hydroxide have strong alkalinity, can be efficiently etched with the nano-pit forming powder, and increase the surface area of the drill bit; meanwhile, the two types of alkaline substances are easy to be eluted and do not react with the remaining components in the matrix, and do not have negative effects on the performance of the drill bit.

[0060] In summary, the present application has the following beneficial effects:

[0061] 1. The Fe powder, Cu powder, nano-pit forming powder, Ni-Cr alloy, powder lubricant, rare earth Pr, rare earth Ce, nano-NbC, and carbon nanotube in the present application cooperate with each other, optimize the graphitization problem of diamond in the iron-based matrix, the problem of loose combination of diamond and matrix when the soft phase such as Cu is added, and the problem of water cooling required by the drill bit; meanwhile, the diamond and the matrix in the present application are tightly combined, which ensures that the diamond is fully worn out before falling off, so that the drill bit is suitable for drilling hard rock, and the service life of the drill bit is greatly increased;

[0062] 2. The diamond with a particle size of 40-45 mesh and a concentration of 50%vol is preferably used in the present application, which enables the matrix to fully embed the diamond and enables the drill bit to have high rock crushing capacity;

[0063] 3. The powder lubricant in the present application is WS2 or CaF2, both of which can form a lubricating film on the surface of the Ni, Cr, and other components in the matrix, so that the components in the matrix are fully dispersed and tightly combined, thereby reducing the probability of cracking of the matrix and improving the tolerance and continuous operation capacity of the matrix;

[0064] 4. The method of the present application performs ultrasonic dispersion treatment on the nanoscale materials in the matrix components before mixing, which reduces the possibility of agglomeration of the nanoscale materials and enables the components in the matrix to be uniformly dispersed; in addition, the method of the present application performs surface pit treatment on the diamond before hot pressing and sintering, which increases the contact area between the diamond and the matrix and enables them to be tightly combined, so that the diamond falls off only after being fully worn out, thereby optimizing the drill bit wear caused by the premature falling off of the diamond in the related art; meanwhile, the surface of the drill bit is etched and the friction is increased after sintering, so that the diamond can quickly cut at the initial stage of the drilling operation, thereby increasing the working efficiency of the drill bit;

[0065] 5. The surface treatment liquid in the present application can be one or a mixture of multiple kinds of perchloric acid, nitric acid, and sulfuric acid, which have strong oxidizing properties and can consume C elements on the surface of the diamond and form nanoscale pits, thereby increasing the surface area of the diamond and enabling the diamond to be tightly combined with the matrix;

[0066] 6、The etching solution of the present application can use alkali metal hydroxide or alkaline earth metal hydroxide, both of which can efficiently dissolve nano-aluminum oxide powder, so as to increase the surface area of the drill bit, so that the diamond can quickly form a cutting edge in the initial drilling operation. DETAILED DESCRIPTION

[0067] The present application is further described in detail below in combination with examples.

[0068] The raw materials used in the embodiments of the present application can be obtained by market purchase. Among them, the diamond is purchased from Ezhou Songli Diamond Product Factory, the particle size is 35-40 mesh, 40-45 mesh and 45-50 mesh, and the model is A20 diamond polycrystal; the Fe powder is purchased from Shanghai Xianxin Material Technology Co., Ltd., the particle size is 100-200 mesh, and the purity is analytical pure; the Cu powder is purchased from Jinjile Chemical Co., Ltd., the particle size is 100-200 mesh, and the purity is analytical pure; the Ni-Cr alloy is selected as Ni80Cr20 alloy, purchased from Hebei Guifa Wear-resistant Material Co., Ltd., the particle size is 150-270 mesh; the rare earth Pr and the rare earth Ce are both purchased from Shanghai Gelun Technology Co., Ltd., the purity is analytical pure; the nano-aluminum oxide is purchased from Shanghai Huijingnan New Material Co., Ltd., the particle size is 30 nm, and the purity is analytical pure; the WS2 is purchased from Zhejiang Yame Nanometer Technology Co., Ltd., the purity is analytical pure; the CaF2 is purchased from Hubei Xinmingtai Chemical Co., Ltd., the purity is 98%; the NbC is purchased from Zhejiang Yame Nanometer Technology Co., Ltd., the purity is analytical pure; the carbon nanotube is purchased from Shanghai Yuanye Biological Technology Co., Ltd., the purity is ≥95%, the diameter is 20-40 nm, and the length is 1-2 μm.

[0069] EMBODIMENT

[0070] EMBODIMENTS 1-5

[0071] As shown in Table 1, the main difference between EMBODIMENTS 1-5 is that the raw material ratio is different.

[0072] The following is illustrated by taking EMBODIMENT 1 as an example. Among them, the nano-pit powder is selected as nano-aluminum oxide powder; the powder lubricant is selected as WS2; the surface treatment solution is selected as nitric acid with a mass fraction of 50%; the etching solution is selected as sodium hydroxide with a concentration of 0.5 mol / L; in step (4), the volume ratio of glycerol to anhydrous ethanol in the glycerol-anhydrous ethanol mixed solution is 1:1.

[0073] EMBODIMENT 1 provides an iron-based impregnated diamond drill bit for hard rock drilling which can be dried and operated, and a preparation method thereof, which comprises the following steps:

[0074] (1) Pre-mixed material

[0075] The Fe powder, Cu powder, Ni-Cr alloy, rare earth Pr and rare earth Ce are weighed according to the mass percentage and mixed into coarse material;

[0076] (2) Mixing

[0077] The nanometer cratering powder, nanometer NbC, and carbon nanotube were weighed by mass percentage, added with 20 ml of anhydrous ethanol and mixed uniformly, and then dispersed by ultrasonic for 20 min to obtain a nanometer mixture; the powder lubricant was weighed by mass percentage, and the nanometer mixture was mixed with the coarse material and the powder lubricant, the ball-to-material ratio was set to 2:1, the rotation speed was 400 r / min, and the nanometer mixture was ball milled for 2.5 h by using a Fritsch planetary ball mill to obtain a matrix mixture;

[0078] (3) Diamond surface cratering treatment

[0079] The diamond of 40-45 mesh was selected, immersed in distilled water, and cleaned by ultrasonic for 3 min to remove grease and dust, and then cleaned with anhydrous ethanol and dried; 200 ml of surface treatment liquid was measured, the diamond was immersed in the surface treatment liquid, and stirred at a speed of 60 r / min for 15 min; the diamond was washed with distilled water and anhydrous ethanol and dried to obtain the cratering treated diamond;

[0080] (4) Hot-pressing sintering

[0081] The matrix mixture and the cratering treated diamond were mixed uniformly in a glycerol-anhydrous ethanol mixed solution at a volume ratio of 1:1, and the concentration of the diamond was 50%vol; then the mixed diamond and the matrix were laid flat in a graphite mold; the drill steel body was placed on the mold, a ZPM-100E medium-frequency induction heating furnace was used to maintain the temperature at 980°C and the pressure at 15 MPa, and the drill was hot-pressed sintered for 8 min and kept for 6 min, and then cooled to form a drill rough product;

[0082] (5) Drill etching and friction increasing treatment

[0083] The drill rough product was immersed in the etching liquid with the matrix facing down, so that the matrix was completely immersed in the etching liquid, and maintained for 8 min, then washed with deionized water, and then dried to obtain a hard rock drilling iron-based impregnated diamond drill that can be dry operated.

[0084] Table 1

[0085]

[0086]

[0087] Example 6

[0088] The difference between this example and Example 2 is that the powder lubricant is CaF2.

[0089] Example 7

[0090] The difference between this example and Example 3 is that the powder lubricant is CaF2.

[0091] Example 8

[0092] The difference between this example and Example 4 is that the powder lubricant is CaF2.

[0093] Example 9

[0094] The difference between this example and Example 3 is that the surface treatment liquid in step (3) is 100 ml of 20% mass fraction of perchloric acid.

[0095] Example 10

[0096] The difference between this example and Example 3 is that the surface treatment liquid in step (3) is 100 ml of 90% mass fraction of sulfuric acid.

[0097] Example 11

[0098] The difference between this example and Example 3 is that the etching liquid in step (5) is 0.2 mol / L of barium hydroxide.

[0099] Comparative Example

[0100] Comparative Examples 1-2

[0101] Comparative Examples 1-2 are compared with Example 3, the difference is that the diamond particle size selected in step (3) of the preparation method is different, as shown in Table 2.

[0102] Table 2

[0103]

[0104] Comparative Examples 3-4

[0105] Comparative Examples 3-4 are compared with Example 3, the difference is that the volume ratio of diamond to matrix in step (4) of the preparation method is different, as shown in Table 3.

[0106] Table 3

[0107]

[0108] Comparative Example

[0109] Comparative Example 1

[0110] An iron-based impregnated diamond drill bit is prepared according to the preparation method of Example 1 of the Chinese invention patent with the authorized publication number CN102828696B.

[0111] Comparative Example 2

[0112] This comparative example is compared with Example 1, the difference being that the Cu powder is absent in the tire body component, and the mass percentage of the Fe powder is 84.82%.

[0113] Comparative Example 3

[0114] This comparative example is compared with Example 1, the difference being that the nano-pitted powder is absent in the tire body component, and the mass percentage of the Fe powder is 78.82%; and step (5) is absent in the preparation method.

[0115] Comparative Example 4

[0116] This comparative example is compared with Example 1, the difference being that the Ni-Cr alloy is absent in the tire body component, and the mass percentage of the Fe powder is 76.82%.

[0117] Comparative Example 5

[0118] This comparative example is compared with Example 1, the difference being that the powder lubricant is absent in the tire body component, and the mass percentage of the Fe powder is 74.82%.

[0119] Comparative Example 6

[0120] This comparative example is compared with Example 1, the difference being that the rare earth Pr is absent in the tire body component, and the mass percentage of the Fe powder is 73.52%.

[0121] Comparative Example 7

[0122] This comparative example is compared with Example 1, the difference being that the rare earth Ce is absent in the tire body component, and the mass percentage of the Fe powder is 73.22%.

[0123] Comparative Example 8

[0124] This comparative example is compared with Example 1, the difference being that the nano-NbC is absent in the tire body component, and the mass percentage of the Fe powder is 74.82%.

[0125] Comparative Example 9

[0126] This comparative example is compared with Example 1, the difference being that the carbon nanotube is absent in the tire body component, and the mass percentage of the Fe powder is 72.9%.

[0127] Comparative Example 10

[0128] This comparative example is compared with Example 1, the difference being that step (2) in the preparation method is different. Step (2) in the preparation method of this comparative example is:

[0129] The nano-pitted powder, the nano-NbC, the carbon nanotube, and the powder lubricant are weighed according to the mass percentage and mixed, the ball-to-powder ratio is set to 2:1, the rotation speed is 400 r / min, and the planetary ball mill is used for fully ball milling for 2.5 h to obtain the tire body mixture.

[0130] Comparative Example 11

[0131] This comparative example is compared with Example 1, the difference being that step (3) is absent in the preparation method.

[0132] Detection method and test method

[0133] A, mechanical property detection:

[0134] 1. Rockwell hardness: select three points on the diamond drill bit of each example, comparative example and comparative example for indentation hardness test, select HR-150A type Rockwell hardness tester for testing, select steel ball with specification of HRBφ1.588 for indenter, set pressure to 150 kgf, pressurization time to 13 s, test three times, and take average value.

[0135] 2. Bending strength: use CTM2500 type microcomputer control electronic universal material testing machine, adopt three-point bending test method to determine the bending strength of sample; set the pressurization speed to 20 N / s, and the span to 24.5 mm.

[0136] 3. Impact toughness: use PTM2450 type pendulum impact testing machine, set the initial angle of pendulum to 150°, and the total impact energy to 450 J, measure the absorbed work of each hole drill bit.

[0137] 4. Wear ratio: use DHM-1 type wear ratio tester for testing; set the rotating speed of SiC grinding wheel to 25 m / s, and the friction time to 200 s, wash and dry each hole drill bit before and after testing, weigh the weight difference of hole drill bit and grinding wheel before and after testing with analytical balance, and the ratio of weight difference of grinding wheel to weight difference of hole drill bit is the wear ratio.

[0138] 5. Density: use AR-300VP multifunctional density tester to measure the density of matrix by using the principle of drainage method.

[0139] B, drilling experiment:

[0140] The XY-4 drilling machine is used, the drilling pressure is set to 50 N, the rotating speed is set to 600 r / min, the drilling object is granite with a drillability of 8, two groups of experiments are carried out by setting the pump volume of cooling water to 5 L / min and 0 L / min respectively, the hole drilling bit consumption and the drilling efficiency are recorded and calculated according to the experimental results; after each group of experiment with the pump volume of 5 L / min is finished, the fallen diamonds are collected, the mass of the fallen diamonds is weighed by using the Mettler Toledo XP6U electronic balance with an accuracy of 100000th, one largest data and one smallest data are removed, the average residual mass of the diamonds is calculated, and the utilization rate of the diamonds is calculated according to the following formula: diamond utilization rate = (original mass of diamonds-average residual mass of diamonds) / original mass of diamonds, wherein the diamonds in the comparative example 1 are counted by 35 meshes, the original mass of a single diamond is regarded as 0.0015 g, the diamonds in the comparative example 2 are counted by 45 meshes, the original mass of the diamonds is regarded as 0.0030 g, the diamonds in each of the other examples, the comparative examples and the comparative examples are counted by 40 meshes, and the original mass of the diamonds is regarded as 0.0022 g.

[0141] The mechanical property detection results are shown in Table 4, and the drilling experiment detection results are shown in Table 5.

[0142] Performance detection test

[0143] Table 4

[0144]

[0145]

[0146]

[0147] Table 5

[0148]

[0149]

[0150] In combination with examples 1-5, comparative example 1 and Table 4, it can be seen that the Rockwell hardness, bending strength, impact toughness, wear ratio and density of the comparative example 1 are all not as good as those of examples 1-5, because the components of the tire bodies of examples 1-5 are synergistically matched, so that the tire body is tight, thereby optimizing the mechanical properties of the hole drill; in the comparative example 1, in order to make the diamonds fall off quickly, the mechanical properties of the drill bit are reduced; therefore, it can be known that the drill bit in the comparative example 1 actually realizes the hard rock drilling in a way of consuming a large amount of drill bits, and the applicability thereof is not as good as that of the hole drill of the present application.

[0151] In combination with Examples 1-5, Comparative Example 1 and Table 5, it can be seen that the drilling efficiency of Comparative Example 1 is good when the cooling water pump quantity is 5 L / min, but the drill bit consumption is much higher than that of Examples 1-4, and the utilization rate of diamond is only about 30%, which is much lower than that of Examples 1-5. This is because the soft phase elements such as Cu and Zn are added in Comparative Example 1, which can ensure the rapid diamond edge, but also reduces the embedding ability of the matrix to the diamond; when the diamond is crushed, the volume of the diamond is consumed by 30% after the diamond is crushed, and the diamond will fall off from the matrix, so the drill bit consumption of Comparative Example 1 is higher under the same drilling efficiency; and the application cooperates the Fe powder, Cu powder, nano-pit powder, Ni-Cr alloy, powder lubricant, rare earth Pr, rare earth Ce, nano-NbC and carbon nanotube in the matrix, so that the matrix is firmly embedded with the diamond, and the utilization rate of the diamond is more than 50% and even tends to 70% according to Table 5, which greatly improves the utilization rate of the diamond compared with Comparative Example 1 under the similar drilling efficiency.

[0152] In combination with Examples 1-5, Comparative Example 1 and Table 5, it can be seen that Comparative Example 1 has no drill bit consumption detection data when the cooling water pump quantity is 0 L / min, because in the drilling experiment, if there is no cooling effect of cooling water, the drill bit of Comparative Example 1 will work continuously at high temperature, although the Cu in the matrix component can dissipate heat, but the mechanical properties are poor, the embedding ability of the matrix is weak, and the heat is uneven, and the drill bit is seriously damaged during continuous operation; and the hole drills of Examples 1-5 still have high drilling efficiency without cooling water, because the Cu and Ce of Examples 1-5 can cooperate to dissipate heat, and the matrix and the diamond are firmly embedded, and the mechanical properties of the hole drill are excellent, which can adapt to dry drilling operation.

[0153] In summary, compared with the drill bit of Comparative Example 1, the hole drills of Examples 1-5 have more excellent Rockwell hardness, bending strength, impact toughness and wear ratio, and at the same time, the hole drills of the application have lower consumption rate and need less cooling water, and even can be applied to dry drilling operation.

[0154] In combination with Example 1, Comparative Example 2 and Tables 4 and 5, it can be seen that the matrix component of Comparative Example 2 lacks Cu powder, and the soft phase in the matrix is less than that of Example 1, so the wear ratio of Comparative Example 1 is higher; but the bending strength and impact toughness of Comparative Example 2 are significantly lower than those of Example 1, which may be because the Cu powder as a soft phase can increase the bending strength of the matrix, and if the Cu powder is lacking, the matrix will become brittle and hard, which is not conducive to drilling operation;

[0155] Due to the hard texture, the abrasion ratio is higher, and the drilling consumption of Comparative Example 2 is less when the cooling water pump flow is 5 L / min, and the diamond blade efficiency is lower. When the cooling water pump flow is 0 L / min, Comparative Example 2 cannot drill in this state, because the thermal conductivity of Cu is excellent, and the heat generated by the high-speed rotation of the drill bit can be dissipated. Comparative Example 2 lacks Cu powder in the matrix component, so the drill bit is easily damaged under the high temperature of dry drilling.

[0156] In combination with Example 1 and Comparative Example 3, and Tables 4 and 5, it can be seen that the mechanical properties of Comparative Example 3 are not much different from those of Example 1, but the drilling efficiency of Comparative Example 3 is lower, because Comparative Example 3 lacks nano-pit powder in the matrix component, and the surface of the drill bit is not treated by etching liquid in the preparation method, so the surface of the drill bit is relatively smooth, and the diamond is not easy to come out at the beginning of drilling, which causes the drilling efficiency of Comparative Example 3 to be slightly lower.

[0157] In combination with Example 1 and Comparative Example 4, and Tables 4 and 5, it can be seen that Comparative Example 4 does not contain Ni-Cr alloy, and Cr element can reduce the impact toughness of the drill bit, making it hard and brittle, so Comparative Example 4 has better impact toughness than Example 1.

[0158] Comparative Example 4 does not contain Cr element, and cannot form a carbide layer on the surface of the diamond, so, similar to the related art, in the hot-pressing sintering process of Comparative Example 4, Fe powder promotes the graphitization of diamond, reducing the rock breaking ability of diamond, which results in that the drilling efficiency of Comparative Example 4 is significantly lower than that of Example 1.

[0159] In combination with Example 1 and Comparative Example 5, and Tables 4 and 5, it can be seen that the matrix component of Comparative Example 5 lacks powder lubricant, and the powder lubricant can reduce the surface energy of each component of the matrix, so that the components of the matrix are combined more tightly. Therefore, Example 1 has more excellent mechanical properties. At the same time, when the powder lubricant is lacking in the matrix component, the difference in the thermal expansion coefficients of Ni, Cr and Fe in the component is large, and only the crack resistance of rare earth Ce cannot optimize the performance of the drill bit well. At the same time, Comparative Example 5 loses the lubricating effect of the powder lubricant, and Fe and Cu are easy to produce crystalline aggregation during sintering, thereby reducing the bonding strength of the matrix and the diamond, increasing the drill bit consumption of Comparative Example 5, and reducing the diamond utilization rate. Therefore, the drilling efficiency and drill bit consumption of Comparative Example 5 are both poor.

[0160] In combination with Example 1 and Comparative Example 6, and Tables 4 and 5, it can be seen that the impact toughness of Comparative Example 6 is lower than that of Example 1, and the diamond utilization rate is only 0.45, and the drilling efficiency and drill bit consumption are also inferior to those of Example 1, because Cr can reduce the impact toughness of the drill bit, and Pr is lacking in Comparative Example 6, which cannot compensate for the impact toughness of the drill bit, thus possibly causing the connection between the diamond and the matrix to be a rigid connection, and the matrix can crack or break when the diamond is working, thereby causing the diamond of Comparative Example 6 to be unable to be fully utilized, and the values of the drilling efficiency and the drill bit consumption to be poor.

[0161] In combination with Example 1 and Comparative Example 7, and Tables 4 and 5, it can be seen that the drill bit consumption and the diamond utilization rate of Comparative Example 7 are poor, because the matrix component of Comparative Example 7 lacks rare earth Ce; the difference between Ni and Cr and the thermal expansion coefficient of the diamond is large, which can cause micro-level fine cracks to appear in the matrix during hot-pressing sintering, which can not be reflected in the data of the mechanical property detection of the drill bit, but in actual drilling, as the rock breaking work of the drill bit continues and the temperature rises, the cracks can cause part of the matrix to fall off from the drill bit, thereby increasing the consumption of the drill bit, and thus the drilling experimental data of Example 1, which contains rare earth Ce in the matrix component, are more excellent.

[0162] On the other hand, a large amount of heat is generated during the drilling operation of the drill bit of Comparative Example 7, and Cu in the matrix component conducts the heat out, but Comparative Example 7 lacks Ce, which cannot make the heat in the matrix evenly distributed, thus possibly causing the matrix to fall off or cracks to appear, which can also be the reason why the drilling experimental data of Comparative Example 7 are poor.

[0163] In combination with Example 1 and Comparative Examples 8 and 9, and Tables 4 and 5, the mechanical properties of Comparative Examples 8 and 9 are all inferior to those of Example 1, and the data of Comparative Example 9 are even worse, because Example 1 contains both NbC and carbon nanotubes, which together compensate for the hard phase of the matrix, if NbC is lacking, only the carbon nanotubes cannot compensate for the "softening" effect of Cu on the matrix, the reason can be that the length of the carbon nanotubes is microns, which cannot fill the nanoscale voids in the matrix component; at the same time, if the carbon nanotubes are lacking, the "softening" effect of Cu also cannot be compensated, the reason can be that the carbon nanotubes are inserted in the matrix and have good bending strength, thereby increasing the mechanical properties of the hole drill.

[0164] Compared with Comparative Example 8 and Comparative Example 9, the mechanical properties of Comparative Example 9 are worse than those of Comparative Example 8, which is probably because the carbon nanotubes are randomly inserted into the carcass component and sintered into shape. After sintering, the carbon nanotubes greatly improve the mechanical properties of the carcass due to their excellent tensile strength and bending strength. Therefore, compared with NbC, the carbon nanotubes have a more excellent strengthening effect on the mechanical properties of the carcass. However, due to the difference in particle size of NbC and carbon nanotubes, the mechanism of action is different. The two work together to efficiently increase the mechanical strength of the carcass component, and one is indispensable to the other.

[0165] Combined with Example 1 and Comparative Example 10, and Tables 4 and 5, it can be seen that the detection data of Comparative Example 10 are all worse than those of Example 1. This is because in the preparation process of Comparative Example 10, the nanoscale materials are directly mixed without ultrasonic treatment, so that the nanoscale materials are agglomerated and cannot be uniformly dispersed in the carcass, thereby reducing the mechanical properties of the drill bit. At the same time, this uneven dispersion also makes the carcass not firm to the diamond inlay, thereby reducing the drilling efficiency of the drill bit.

[0166] Combined with Example 1 and Comparative Example 11, and Tables 4 and 5, it can be seen that the drilling efficiency and drill bit consumption of Comparative Example 11 are significantly lower than those of Example 1. This is because no surface cratering treatment is performed on the diamond during the preparation of Comparative Example 11, so that the diamond is not tightly combined with the carcass. During the drilling process, the diamond will fall off when its volume is about 40% of the original size, thus greatly increasing the drill bit consumption of Comparative Example 11.

[0167] Combined with Example 3, Comparative Examples 1-2, and Tables 4 and 5, it can be seen that because Comparative Example 1 uses smaller particle size diamonds, the diamonds are too fully inlaid in the carcass, so it is difficult to break the rock and the drilling efficiency is reduced. Because Comparative Example 2 uses larger particle size diamonds, the diamonds are not fully inlaid in the carcass and may fall off too early during rock breaking, thus increasing the drill bit consumption.

[0168] Combined with Example 3, Comparative Examples 3-4, and Tables 4 and 5, it can be seen that because the carcass of Comparative Example 3 is more, the diamond concentration is smaller, and it is difficult to break the rock, resulting in low drilling efficiency. The carcass of Comparative Example 4 is less, and the inlaying ability of the diamond is weak, so that the diamond falls off too early during rock breaking, increasing the drill bit consumption and reducing the utilization rate of the drill bit.

[0169] Combined with Example 3 and Examples 6-8, and Tables 4 and 5, it can be seen that whether CaF2 or WS2 is selected as the material lubricant, the prepared drill bit has good performance.

[0170] In combination with Embodiment 3 and Embodiments 9-11 and Tables 4 and 5, it can be seen that selecting perchloric acid, nitric acid, or sulfuric acid as the surface treatment liquid can make the diamond closely combined with the matrix, thereby making the drill bit have good performance; selecting alkali metal hydroxide or alkaline earth metal hydroxide can quickly and efficiently dissolve nano-aluminum oxide, thereby increasing the roughness of the matrix, making the drill bit quickly sharpened at the initial stage of drilling, and increasing the drilling efficiency.

[0171] The specific embodiments are merely illustrative of the present application, and are not intended to limit the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An iron-based impregnated diamond drill bit for dry drilling of hard rock, comprising a drill steel body and diamonds, characterized in that: Also included is a matrix, the diamond being embedded in the matrix; the matrix includes the following components in mass percentage: (1) premix Fe powder, Cu powder, Ni-Cr alloy, rare earth Pr, and rare earth Ce are weighed in mass percentage and mixed into coarse material; (2) mixing Nano-pitted powder, nano-NbC, and carbon nanotubes are weighed in mass percentage, added into anhydrous ethanol, and then ultrasonically dispersed to obtain nano-mixture; powder lubricant is weighed in mass percentage, and the nano-mixture is mixed with the coarse material and the powder lubricant, and then ball-milled to obtain matrix mixture; (3) diamond surface pitting treatment Diamonds of appropriate particle size are selected, and a surface treatment liquid is used to pit the diamonds to obtain pitted diamonds; (4) hot-pressing sintering The matrix mixture and the pitted diamonds are mixed uniformly in a glycerol-anhydrous ethanol environment, and then laid flat in a graphite mold; a drill steel body is placed on top, and hot-pressing sintering is performed at a temperature of 960-1000℃ and a pressure of 14.5-15.5 MPa; cooling and forming to obtain a drill rough product; (5) drill etching and friction increasing treatment The bottom matrix part of the drill rough product is subjected to surface wetting treatment for 5-10 min using an etching liquid, and then cleaned, dried, and obtained is the hard rock drill hole iron-based diamond-embedded drill bit that can be dry-operated.

2. The dryable, work-hardened, iron-based, impregnated, diamond, core drill bit for drilling hard rock according to claim 1, characterized in that: The carcass comprises the following components, in mass percentages:

3. The dryable, work-hardened, iron-based, impregnated, diamond, core drill bit of claim 1, wherein: The particle size of the diamond is 40-45 mesh, and the concentration is 50%vol.

4. The dryable, work-hardened, iron-based, impregnated, diamond, core drill bit of claims 1 or 2, wherein: The nano-pitted powder is nano-alumina powder.

5. The dryable, work-hardened, iron-based, impregnated, diamond, core drill bit of claims 1 or 2, wherein: The powder lubricant is WS2 or CaF2.

6. The dryable, work-hardened, iron-based, impregnated, diamond, core drill bit of claim 1, wherein: The surface treatment liquid used in step (3) is a mixture of one or more of hydrochloric acid, nitric acid, and sulfuric acid.

7. The dry serviceable iron-based impregnated diamond core drill bit for hard rock drilling as claimed in claim 1, wherein: The etching liquid used in step (5) is a mixture of one or more of alkali metal hydroxides or alkaline earth metal hydroxides.

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