Matrix material for diamond-impregnated drill bits for superhard and compact weakly abrasive strata, and preparation method and application thereof

Abstract

The application discloses a kind of superhard compact weak abrasive stratum with diamond impregnated drill matrix material and its preparation method and application, belong to metal product technical field.The application provides a kind of diamond impregnated drill matrix material for solving superhard compact weak abrasive stratum drill easy to slip, polishing and other problems, and the raw material composition is as follows:WC powder 4~6%, Fe pre-alloy powder 50~55%, 660 copper powder 30~35%, nickel powder 2.7~4%, cobalt powder 2.7~4%, titanium powder 2.7~4%.The application uses WC powder as skeleton phase material, uses iron pre-alloy powder and 660 copper powder as main body, adds reinforcing elements nickel, cobalt and titanium, so that the matrix bending strength reaches more than 600MPa, and the Rockwell hardness is about 20HRC, which reflects that the matrix wear resistance is highly compatible with the wear characteristics of superhard compact weak abrasive stratum, the strength meets the requirements of special-shaped lip diamond impregnated drill, and solves the problems of drill easy to slip, polishing and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal products, and particularly relates to a matrix material of an impregnated diamond drill bit for super-hard and compact weakly abrasive strata and a preparation method and application thereof. BACKGROUND

[0002] When the impregnated diamond drill bit drills into super-hard and compact weakly abrasive strata, the wear rate of the diamond particles should match the wear rate of the matrix. If the wear rates of the matrix and the diamond are similar, the old diamond that is worn can be timely removed, and the new diamond can be timely exposed, that is, a better drilling speed can be ensured. If the wear rate of the matrix is greater than the wear rate of the diamond, that is, the wear resistance of the matrix is relatively low for the drilled rock, the diamond will be prematurely removed, affecting the service life of the drill bit. If the wear rate of the matrix is less than the wear rate of the diamond, that is, the wear resistance of the matrix is relatively high for the drilled rock, the old diamond that is worn cannot be timely removed, and the new diamond cannot be timely exposed, and the drill bit appears to be "slipping" and "polishing".

[0003] At present, the impregnated diamond drill bit commonly used for drilling into super-hard and compact weakly abrasive strata is mostly of a special lip structure, such as a gear tooth drill bit, a concentric ring tooth drill bit, a slotting type drill bit, a bionic special tooth type drill bit, a multi-stage matrix spiral type distribution structure drill bit, Figure 1 and the like. The special lip structure of these drill bits can reduce the contact area between the drill bit and the rock at the bottom of the hole, increase the cutting pressure of a single diamond on the hard rock, and thus improve the drilling efficiency.

[0004] However, the special lip structure has a negative impact on the integrity of the drill bit, and the strength of a single matrix tooth is reduced. Therefore, in order to prevent the matrix tooth from being damaged and affecting the service life of the drill bit, the matrix material needs to have good toughness. In addition, in order to prevent the diamond from being prematurely removed, the matrix needs to have a good holding strength for the diamond. The super-hard and compact weakly abrasive strata have weak wear on the matrix of the drill bit due to their own characteristics. In order to ensure a suitable exposure speed, the wear resistance of the matrix needs to be appropriately reduced compared with that of the conventional impregnated diamond drill bit.

[0005] In summary, the impregnated diamond drill bit for super-hard and compact weakly abrasive strata has the following requirements for the matrix material: (1) the wear resistance of the matrix material is relatively low as a whole; (2) the matrix material has a good holding strength for the diamond particles; and (3) the matrix material has good toughness to prevent the matrix block from being damaged. However, most of the matrix materials currently available are difficult to meet these requirements at the same time.

[0006] CN102828696A discloses a hard and slippery formation drilling with iron-based impregnated diamond drill bit, which is composed of drill bit steel body and iron-based matrix material, the iron-based matrix material is composed of iron-based matrix and diamond particles, the diamond particles are impregnated on the iron-based matrix, the volume percentage of diamond particle content is 45%-75%, and the particle size is 35~50 mesh; the iron-based matrix is composed of the following components by mass percentage: iron powder 65%~72%, zinc powder 10%~14%, 663 bronze powder 14%~18%, manganese powder 1%, and nickel powder 2%. The method aims at the slipping phenomenon of the existing diamond drill bit when drilling in hard and weak abrasive formation, and provides an iron-based impregnated diamond drill bit for hard and slippery formation drilling. The drill bit is a hot-pressed iron-based impregnated diamond drill bit, which has moderate hardness (the hardness of the embodiment is HRC15±3), significantly improves the performance and quality of the diamond drill bit when drilling in hard and slippery formation, has strong pertinence, and reduces the manufacturing cost of the drill bit. However, the strength is too low in the art, and there is a risk of tooth breakage for special-shaped lip drill bit, and the strength of the drill bit is not disclosed.

[0007] CN101403067A discloses a matrix formula of impregnated diamond drill bit for weak abrasive hard formation, which is mixed by 20%~30% of 200 mesh fine cast tungsten carbide, 20%~30% of 800 mesh fine tungsten carbide, 10%~20% of 80~200 mesh tungsten powder, 20~25% of 400 mesh fine copper powder, 10~15% of 800 mesh fine nickel powder, 5~10% of 800 mesh fine manganese powder, 2~5% of 400 mesh fine zinc powder and 2~5% of 400 mesh fine cobalt powder, and is pressed at a temperature of 1050℃ and a pressure of 2KN. The method adjusts the ratio of cast tungsten carbide and tungsten carbide to tungsten to control the hardness of the matrix material, so that the wear rate of the matrix material is close to the wear rate of the diamond, to realize the organic combination of weak wrapping and strong wrapping of the diamond. However, the hardness and strength of the matrix are not disclosed, it is difficult to predict whether it is suitable for hard and dense weak abrasive formation; meanwhile, according to the research of the present application, the content of WC in the matrix cannot be too high for hard and dense weak abrasive formation, and pure WC is a brittle material, which needs to be balanced by adding other binder materials. The method mainly uses WC / W as raw material, and it is difficult to predict whether it is suitable for hard and dense weak abrasive formation.

[0008] CN105018780A discloses a hard phase-free matrix formula for impregnated diamond drill bit, and the composition and mass ratio of the matrix material are as follows: pure Fe powder 24-31wt%, pure Ni powder 8-15wt%, P powder, B powder and Si powder each 0.2-1.5wt%, Cu alloy 46.5-66.4wt%, pure Co powder 1-3wt%, and the particle size is 200-400 mesh. However, the hardness and strength of the matrix are not disclosed, and it is difficult to predict whether it is suitable for hard and dense weak abrasive formation.

[0009] CN114351023A discloses a hydrogenated zirconium reinforced impregnated diamond bit iron-based matrix material, which is composed of the following raw materials in parts by weight: iron-based skeleton material 45-60 parts, metal bonding material 40-55 parts, hydrogenated zirconium 0.2-0.6 parts, the iron-based skeleton material and the metal bonding material both use pre-alloyed powder; the metal bonding material is iron-copper-nickel-tin pre-alloyed powder and / or iron-copper-zinc-titanium pre-alloyed powder; the iron-copper-zinc-titanium pre-alloyed powder is composed of the following components in mass percentage: copper: 10-30%, zinc: 20-40%, titanium: 2-6%, silicon: 0-2%, and the balance is iron and unavoidable impurity elements. The purpose of the method is to improve the matrix wear resistance and mechanical properties, and it is not suitable for hard and dense weak abrasive formation.

[0010] Therefore, it is of great significance to develop a new type of impregnated diamond bit matrix formula suitable for superhard formation and improve the comprehensive drilling performance of the bit in such formation, so as to realize efficient and economic drilling. SUMMARY

[0011] The purpose of the present application is to solve the problems that the conventional impregnated diamond bit cannot effectively drill into the rock formation and the mechanical drilling speed is sharply reduced when drilling in superhard and dense weak abrasive formation due to the mismatch of the matrix performance, and to develop a high-performance impregnated diamond bit matrix formula, bit and preparation method to significantly improve the drilling efficiency in superhard formation.

[0012] To achieve the above-mentioned purpose, the present application first provides an impregnated diamond bit matrix material for superhard and dense weak abrasive formation, which is composed of the following components: WC powder: 4wt.%~6wt.%, Fe pre-alloyed powder: 50wt.%~55wt.%, 660 copper powder: 30wt.%~35wt.%, nickel powder: 2.7wt.%~4wt.%, cobalt powder: 2.7wt.%~4wt.%, titanium powder: 2.7wt.%~4wt.%.

[0013] Among them, the mass ratio of nickel powder: cobalt powder: titanium powder in the above-mentioned impregnated diamond bit matrix material for superhard and dense weak abrasive formation is 0.9~1.1: 0.9~1.1: 0.9~1.1.

[0014] Among them, the Fe pre-alloyed powder in the above-mentioned impregnated diamond bit matrix material for superhard and dense weak abrasive formation is composed of 55wt% Fe, 31.5wt% Cu, 10wt% Ni and 3.5wt% Sn (which contains a small amount of unavoidable impurities, which is ignored here).

[0015] In the aforementioned matrix material for impregnated diamond drill bits used in ultra-hard, dense, and weakly abrasive formations, the Fe pre-alloyed powder has a purity of not less than 99% and a density of 8.23 ​​g·cm³. -3 The particle size is 300 mesh.

[0016] Based on the research of this invention, the Fe pre-alloy powder is more conducive to achieving flexural strength and wear resistance in the matrix that match the ultra-hard, dense, and weakly abrasive strata compared to other Fe alloys. Therefore, this invention uses the aforementioned Fe pre-alloy powder.

[0017] In the aforementioned matrix material for impregnated diamond drill bits used in ultra-hard, dense, and weakly abrasive formations, the 660 copper powder is composed of 88wt% Cu, 6wt% Zn, and 6wt% Sn (it contains a very small amount of unavoidable impurities, which are negligible here).

[0018] In the aforementioned matrix material for impregnated diamond drill bits used in ultra-hard, dense, and weakly abrasive formations, the purity of the 660 copper powder is not less than 99%, and its density is 8.92 g·cm³. -3 The particle size is 300 mesh.

[0019] According to the research of this invention, 660 copper powder (also known as 660 bronze powder) is more conducive to achieving bending strength and wear resistance of the matrix that matches the ultra-hard, dense, and weakly abrasive strata than other Cu alloys such as 663. Therefore, this invention uses 660 copper powder.

[0020] Preferably, the raw material composition of the above-mentioned impregnated diamond drill bit matrix for ultra-hard, dense, and weakly abrasive formations consists of the following components: WC powder: 5 wt.%, Fe pre-alloyed powder: 52.5 wt.%, 660 copper powder: 32.5 wt.%, nickel powder + cobalt powder + titanium powder: 10 wt.%, with a nickel powder:cobalt powder:titanium powder mass ratio of 1:1:1.

[0021] The present invention also provides a method for preparing the above-mentioned matrix material for impregnated diamond drill bits for ultra-hard, dense, and weakly abrasive formations, which includes the following steps: uniformly mixing the components of the matrix material in proportion, hot pressing and sintering at a sintering temperature of 890~910℃ and a sintering pressure of 19~21MPa, and then cooling to room temperature to obtain the matrix material.

[0022] Alternatively, diamond particles (the amount of diamond particles used when preparing matrix materials is appropriate; the amount of diamond particles used when preparing drill bits depends on the drill bit) and the various components of the matrix materials are mixed evenly in proportion, and then hot-pressed and sintered at a temperature of 890~910℃ and a sintering pressure of 19~21MPa, and then cooled to room temperature to obtain the final product.

[0023] In the above preparation method, the hot pressing sintering process involves holding the temperature for 4 to 6 minutes.

[0024] In this invention, the sintering temperature and holding time have a great influence on the performance of the matrix. After many experiments by the inventors, it is necessary to strictly control the sintering temperature and holding time. Therefore, in the preparation of the matrix material, the sintering temperature is strictly controlled at 890~910℃, the sintering pressure is 19~21MPa, and the holding time is 4~6 minutes.

[0025] "Holding temperature for 5 minutes" means that after the sintering reaches the highest process temperature, the temperature is kept constant for 5 minutes, so that the material is "stewed" for a sufficient time at the optimal sintering temperature. This ensures that the matrix powder can fully complete key processes such as densification, alloying, and good bonding with diamond, and finally obtain a diamond drill bit matrix with uniform and dense structure and excellent performance.

[0026] This invention also provides the application of the aforementioned matrix material for impregnated diamond drill bits used in ultra-hard, dense, and weakly abrasive formations in impregnated diamond drill bits. The matrix material of this invention exhibits wear resistance highly compatible with the wear characteristics of ultra-hard, dense, and weakly abrasive formations, and can meet the matrix strength requirements of many irregularly shaped impregnated diamond drill bits, such as hobbing drill bits, concentric ring-tooth drill bits, slotted drill bits, biomimetic irregular-tooth drill bits, and multi-stage helical distribution matrix drill bits. A schematic diagram of the multi-stage helical distribution matrix drill bit is shown below. Figure 1 As shown, the matrix material of this invention enables the application of impregnated diamond drill bits in ultra-hard, dense, and weakly abrasive formations, thus solving problems such as drill bit slippage and polishing.

[0027] The beneficial effects of this invention are:

[0028] This invention employs a matrix material system with WC powder as the skeleton phase material and iron pre-alloy powder and 660 copper powder as the main components. The iron pre-alloy powder exhibits good formability and thermal conductivity, while the 660 copper powder facilitates sintering and serves as a good binder. Furthermore, to further enhance the matrix's performance, strengthening elements nickel, cobalt, and titanium are added. Nickel provides solid solution strengthening, cobalt offers good formability and is easy to sinter, and titanium improves the holding strength between the matrix and diamond particles, extending the drill bit's lifespan. The pre-alloy matrix, sintered through hot pressing, exhibits superior performance, with a bending strength exceeding 600 MPa and demonstrating good toughness. Its Rockwell hardness is around 20 HRC. This design does not aim for excessively high or low wear resistance, but rather deliberately adjusts the matrix's wear resistance to a level higher than ordinary matrices. This reflects a high degree of compatibility between the matrix's wear resistance and the wear characteristics of ultra-hard, dense, and weakly abrasive formations, meeting the strength requirements for irregularly shaped impregnated diamond drill bits, and providing excellent diamond holding strength. These characteristics are more conducive to the timely emergence and renewal of diamond particles, effectively solving the problems of drill bit slippage and polishing in this type of formation, and ensuring efficient and stable drilling of the drill bit in the target formation. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a diamond-encrusted drill bit structure with a multi-stage spiral distribution of blocks.

[0030] Figure 2 SEM images of the fracture morphology of the matrix specimen containing diamond particles in Example 11 at different observation scales.

[0031] Figure 3 SEM images of the fracture morphology of the matrix specimen containing diamond particles in Example 3 at different observation scales.

[0032] Figure 4 SEM images of the fracture morphology of the matrix specimen containing diamond particles in Example 10 at different observation scales. Detailed Implementation

[0033] The present invention will be further described in detail below through embodiments, but the scope of protection of the present invention is not limited to the embodiments described herein.

[0034] WC material has good thermal conductivity, its coefficient of thermal expansion is close to that of diamond, and it also has good formability and high hardness, making it a superior choice as a matrix material. However, to ensure that the hardness of the new drill bit matrix matches that of hard and dense rock, the WC content cannot be too high, and other materials need to be added to adjust the strength and toughness of the matrix. For example, Fe pre-alloyed powder has weaker performance indicators than WC and is suitable for drilling hard and dense rock to meet the matrix performance requirements. 660 bronze is easy to sinter and is a good bonding material. In addition, to ensure the performance of the new drill bit matrix, some reinforcing materials need to be added, such as Ni, Co, and Ti. Among them, Ni has a solid solution strengthening effect, Co is beneficial to sintering and has good self-sharpening properties, and Ti can improve the bonding strength between the matrix and diamond.

[0035] This invention is based on the requirement that the matrix composition needs to meet the performance requirements of the matrix for drilling hard, dense, and weakly abrasive rocks. The specific functions of each component are as follows: WC powder: framework phase material, ensuring the hardness of the drill bit; Fe pre-alloyed powder: intermediate phase, encapsulating diamond particles and adjusting the performance of the new matrix; 660 bronze powder: binder material, used to bond the matrix to the diamond particles; Ni, Co, Ti: reinforcing phases, improving the toughness of the matrix and the holding strength of the diamond particles. Ni has a solid solution strengthening effect, Co has good formability and is easy to sinter, and Ti strengthens the bond strength between the matrix and the diamond.

[0036] Therefore, the matrix composition of the impregnated diamond drill bit for drilling in hard, dense, and weakly abrasive formations in this invention has been determined. It is primarily composed of Fe pre-alloyed powder, with a small amount of WC powder as the skeleton material, and 660 bronze powder, Ni, Co, and Ti as intermediate adjusting materials. Furthermore, based on preliminary field surveys and experimental studies on drill bit matrices, because quartzite has high hardness and weak abrasiveness, the wear resistance of the matrix cannot be designed to be too high; its hardness should ideally be around HRC20. Preliminary studies on the effects of WC powder, Fe pre-alloyed powder, 663 bronze powder, Ni, Co, and Ti content on the matrix performance have determined the value ranges for each component of the matrix in this invention, as shown in Table 1.

[0037] Table 1. Range of values ​​for each component of the fetal body

[0038]

[0039] Preparation of experimental materials

[0040] The 660 copper powder consists of 88 wt% Cu, 6 wt% Zn, and 6 wt% Sn, while the Fe pre-alloyed powder consists of 55 wt% Fe, 31.5 wt% Cu, 10 wt% Ni, and 3.5 wt% Sn, both with a purity higher than 99%. Diamond particle size was selected as 40 / 50 mesh (40 / 50 mesh indicates the particle size range that passes through a 40-mesh sieve but is retained by a 50-mesh sieve). The physical parameters of the 660 copper powder and Fe pre-alloyed powder are shown in Table 2. WC powder, Ni powder, Co powder, and Ti powder are common commercially available products.

[0041] Table 2 Physical parameters of 660 copper powder and Fe alloy powder

[0042]

[0043] Example

[0044] Based on previous research, the present invention has obtained a specific experimental scheme for the mixing experiment of the matrix components of impregnated diamond drill bits, as shown in Table 3. In Table 3, the mass ratio of Ni:Co:Ti is 1:1:1.

[0045] Table 3 Experimental Scheme for Mixing Carcass Components

[0046]

[0047] 1. Preparation of carcass samples

[0048] The preparation of matrix samples is divided into the preparation of sintered samples containing diamond particles and the preparation of sintered samples without diamond particles. The matrix sample preparation of this invention adopts a hot-pressing sintering process, that is, the matrix powder is uniformly mixed according to the formula ratio, and then the mixed powder is placed in a pre-prepared graphite mold and sintered for an appropriate time under the set sintering temperature and sintering pressure to obtain the target matrix sample.

[0049] The sintering of diamond-free matrix samples involves calculating the filling amount of each matrix powder by the density of each powder, mixing them thoroughly, adding them into a graphite mold, and then sintering.

[0050] For the sintering of matrix samples containing diamond particles, the filling amount of each matrix powder is first calculated, and then the filling amount of diamond particles is calculated (the amount of diamond added is the diamond volume / the total volume of diamond + matrix material components = 20%). Finally, the matrix powder and diamond are mixed evenly and then sintered.

[0051] The dimensions of the matrix samples prepared for this test were 40mm × 14mm × 10mm. Under the same formula, there were 3 matrix block samples containing diamond particles and 1 matrix sample without diamond particles, totaling 76 samples. The matrix samples were prepared in the laboratory of Jinshi Drilling (Tangshan) Co., Ltd., with a sintering temperature of 900℃ and a sintering pressure of 20MPa. After sintering, the matrix samples were deburred and polished.

[0052] 2. Test methods for tire carcass specimen performance

[0053] Hardness Testing: The hardness of the carcass sample is one of the most important indicators of carcass performance, directly related to its wear resistance. Higher carcass hardness results in higher wear resistance. The HR-150A Rockwell hardness tester was used for this hardness test, following the testing methods in "Rockwell Hardness Testing of Metallic Materials". Five points were evenly selected for testing each carcass sample, and the final hardness value of the sample is the average of these five test points.

[0054] Three-point bending strength test: The bending strength test of the tire carcass specimen is mainly to clarify the material properties of the tire carcass material when it fractures under static bending load, which directly reflects the strength and toughness of the spiral tire block and the gauge-maintaining tire block during the drilling process. The equipment used for this bending strength test is a CSS-44100 universal testing machine, and the bending strength test is conducted in accordance with the relevant requirements of GB / T232-2024 "Metallic Materials - Bending Test Method". The bending strength of the tire carcass specimen is calculated according to the following formula: In the formula: denoted as , where is the three-point bending strength (MPa); is the breaking load of the carcass specimen at fracture (KN); is the span of the three-point bending test specimen (mm); is the width of the carcass specimen (mm); and is the height of the carcass specimen (mm). Based on the dimensions of the carcass specimen and the testing equipment, the span during the test is determined to be 30mm, the indenter size is 10mm, and the loading rate is 0.5mm / min. The breaking load of the carcass specimen can be read from the digital display device of the universal testing machine.

[0055] 3. Results and Analysis

[0056] For hardness testing, matrix blocks without diamond particles were used. Five points were evenly selected for testing, and the average value was taken as the hardness of the block corresponding to that formula. For flexural strength testing, matrix blocks containing diamond particles were used. Three blocks were used for each formula, and the average value was taken as the three-point flexural strength of the block corresponding to that formula. The Rockwell hardness results are shown in Table 4, and the three-point flexural strength results are shown in Table 5.

[0057] Table 4 Rockwell hardness results of the carcass formulation in the mixing experiment design

[0058]

[0059] Table 5. Results of three-point flexural strength of the carcass formulation in the compounding experiment.

[0060]

[0061] Considering the drilling characteristics of hard, dense, and weakly abrasive formations, it was determined that the overall hardness of the tire carcass should not be too high, and the hardness of the spiral tire block and the gauge block should be greater than that of the ordinary tire carcass. Therefore, the hardness of the spiral tire block and the gauge block should be maintained at around 20 HRC, so Example 11 is more in line with the requirements.

[0062] 4. Microstructure analysis of tire blocks in the example

[0063] To further investigate the cementation state of the carcass components, some examples conforming to the optimal formulations of diameter-maintaining and spiral carcass components were selected from the sample schemes, such as Example 11; Examples 10 and 3, which respectively do not contain Ni-Co-Ti components and 660-Cu components, were selected as control groups, and their fracture morphology was analyzed by SEM. This SEM experiment was completed at the Key Laboratory of Tectonic Metallogenesis and Hydrocarbon Accumulation, Ministry of Natural Resources, Chengdu University of Technology. SEM images of the fracture morphology of different examples are shown below. Figures 2-4 As shown.

[0064] Under the formulation of Example 11, the Rockwell hardness of the carcass sample was 20.5 HRC and the flexural strength was 608.521 MPa. Figure 2SEM images show the fracture morphology of the matrix specimen containing diamond particles from Example 11 at different observation scales. Figure 2 As can be seen at the observation scale of 200 μm, the test matrix is ​​relatively dense overall, but contains many micro-cracks and micro-etched pores. These uniformly distributed micro-cracks and micro-etched pores ensure that the matrix sample has a low Rockwell hardness and a high roughness, which is beneficial to ensure diamond cutting edge and prevent drill bit slippage and polishing. The diamonds in the test matrix are well embedded in the matrix, with small gaps between them and the matrix, and the diamond surface is less contaminated, making the overall surface relatively smooth and intact, without obvious carbonization. At the observation scale of 30 μm, the dimple fracture on the fracture surface of the test matrix is ​​very obvious and abundant, which ensures that the matrix of Example 11 has a high bending strength (608.521 MPa).

[0065] Under the formulation of Example 3, the Rockwell hardness of the carcass sample was 50.1 HRC and the flexural strength was 501.688 MPa. Figure 3 SEM images show the fracture morphology of the matrix specimen containing diamond particles in Example 3 at different observation scales. Figure 3 As can be seen at the 200 μm observation scale, the test block is relatively dense overall, with few microcracks and pores. There are small gaps between the diamond and the matrix, indicating good embedding. The diamond is relatively intact and smooth, with no obvious carbonization. Because the internal structure of the test block is dense and contains a large amount of WC, the Rockwell hardness of the test block is high (50.1 HRC). At the 20 μm observation scale, the microstructure of the test block is less uniform, with no obvious micropores. It is a mixed fracture with both flat cleavage surfaces and dimples, with varying dimple depths, which leads to a decrease in the flexural strength of the test block (501.688 MPa).

[0066] Under the formulation of Example 10, the Rockwell hardness of the carcass sample was 22.8 HRC and the flexural strength was 501.688 MPa. Figure 4 SEM images show the fracture morphology of the matrix specimen containing diamond particles from Example 10 at different observation scales. Figure 4As can be seen at the 200 μm observation scale, the microstructure of the test piece is uneven and contains large pores. No obvious diamond particles were found on the fracture surface, only diamond inlay pits. Because the WC content of this formulation is low and the porosity is high, the piece has a low Rockwell hardness (22.8 HRC). At the 20 μm observation scale, the microstructure of the test piece is relatively uniform, the fracture surface has some dimple fracture, and it is rich in numerous microspheres with poor adhesion between the spheres. The macroscopic voids and the low adhesion of the microstructure result in a low flexural strength (296.375 MPa) for the test piece.

[0067] In summary, the performance of the matrix is ​​the result of the combined effect of multiple factors. 660-Cu, as the binder, and Ni-Co-Ti, as the reinforcing phase, play a positive role in ensuring the good performance of the matrix. Therefore, based on a comprehensive analysis of the microstructure and macroscopic mechanical properties of the matrix, it meets the performance requirements of the new impregnated diamond drill bit gauge blocks and spiral blocks, satisfying the drilling characteristics of hard, dense, and weakly abrasive formations. The optimal matrix formulation range is: WC powder 4 wt.%~6 wt.%, Fe pre-alloyed powder 50 wt.%~55 wt.%, 660 copper powder 30 wt.%~35 wt.%, nickel powder 2.7 wt.%~4 wt.%, cobalt powder 2.7 wt.%~4 wt.%, titanium powder 2.7 wt.%~ 4wt.%; The optimal carcass composition is: WC powder: 5wt.%, Fe pre-alloyed powder: 52.5wt.%, 660 copper powder: 32.5wt.%, nickel powder: approximately 3.3wt.%, cobalt powder: approximately 3.3wt.%, titanium powder: approximately 3.3wt.% (Ni-Co-Ti: 10.0wt.%).

Claims

1. A matrix material for impregnated diamond drill bits used in ultra-hard, dense, and weakly abrasive formations, characterized in that, Its raw material composition consists of the following components: WC powder: 5 wt.%, Fe pre-alloyed powder: 52.5 wt.%, 660 copper powder: 32.5 wt.%, nickel powder + cobalt powder + titanium powder: 10 wt.%, with a nickel powder:cobalt powder:titanium powder mass ratio of 1:1:1; The Fe pre-alloyed powder is composed of 55 wt% Fe, 31.5 wt% Cu, 10 wt% Ni and 3.5 wt% Sn; The 660 copper powder is composed of 88wt%Cu, 6wt%Zn and 6wt%Sn; The preparation method includes the following steps: uniformly mixing the components of the matrix material in proportion, hot pressing and sintering, sintering temperature 890~910℃, sintering pressure 19~21MPa, and then cooling to room temperature to obtain the product; During hot pressing and sintering, hold at the temperature for 4-6 minutes.

2. The matrix material for impregnated diamond drill bits for ultra-hard, dense, and weakly abrasive formations according to claim 1, characterized in that, The Fe pre-alloyed powder has a purity of not less than 99% and a density of 8.23 ​​g·cm³. -3 The particle size is 300 mesh.

3. The matrix material for impregnated diamond drill bits for ultra-hard, dense, and weakly abrasive formations according to claim 1, characterized in that, The purity of the 660 copper powder is not less than 99%, and the density is 8.92 g·cm³. -3 The particle size is 300 mesh.

4. The application of the matrix material of the impregnated diamond drill bit for ultra-hard, dense, and weakly abrasive formations as described in any one of claims 1 to 3 in impregnated diamond drill bits.

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