Cone angle self-sharpening type high-strength mining cutting pick and gradient manufacturing method thereof

Abstract

The invention relates to the technical field of mining, in particular to a taper angle self-sharpening type high-strength mining cutting pick and a gradient manufacturing method thereof.The taper angle self-sharpening type high-strength mining cutting pick and the gradient manufacturing method thereof.The taper angle self-sharpening type high-strength mining cutting pick comprises the following steps that S1, raw materials are selected and pretreated; gradient composite manufacturing of the cone-angle self-sharpening high-strength mining cutting pick is achieved, different parts of the cutting pick adapt to specific requirements of different parts through gradient change of material performance, the abrasion resistance and impact resistance of the cutting pick are remarkably improved, in addition, the cutting edge of the cone-angle self-sharpening high-strength mining cutting pick is designed to be conical, and the cutting edge of the cone-angle self-sharpening high-strength mining cutting pick is not prone to deformation. Due to the geometrical shape, in the cutting process of the cutting pick, friction and impact can be generated between the conical edge of the cutting pick and rock, even if abrasion occurs, abrasion materials on the edge can fall off due to the dynamic effect, a new sharp edge is exposed, and due to the mechanism, the cutting pick can continuously keep efficient cutting performance under the severe working condition.

Description

Technical Field

[0001] The present invention relates to the technical field of mining, and particularly to a conical angle self-sharpening high-strength mining pick and its gradient manufacturing method. Background Art

[0002] Mining picks are indispensable key components in mining machinery. They directly contact the ore and perform cutting and crushing operations. These picks are generally installed on the cutting heads of coal shearers, roadheaders, continuous miners, etc. In modern mining, with the increasing requirements for production efficiency and cost control, the performance requirements for mining picks are also continuously improving.

[0003] Most of the existing mining picks are made of a single material, such as high manganese steel or cemented carbide. Although these materials themselves have certain wear resistance, in continuous and frequent cutting operations, especially when facing high-hardness ore and harsh working environments, the wear problem of the picks is still very serious. In addition, the existing pick designs generally lack self-sharpening function and gradient distribution design, which results in the inability of the picks to automatically recover and maintain the cutting efficiency after wear, so they need to be replaced frequently. This high-frequency replacement not only increases the maintenance cost but also significantly reduces the overall efficiency of mining operations. Therefore, according to the above problems, a conical angle self-sharpening high-strength mining pick and its gradient manufacturing method are proposed. Summary of the Invention

[0004] The purpose of the present invention is to provide a conical angle self-sharpening high-strength mining pick and its gradient manufacturing method to solve the problem that the existing mining picks generally have poor wear resistance and need to be replaced frequently.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A conical angle self-sharpening high-strength mining pick and its gradient manufacturing method, including the following steps:

[0007] S1. Raw material selection and pretreatment: Select high-purity diamond powder and cemented carbide powder as the main raw materials. The average particle size of the diamond powder is 5 - 10 microns, and the particle size of the cemented carbide powder is 1 - 5 microns. Perform ball milling pretreatment on the diamond powder and cemented carbide powder to improve the fluidity of the powder and the density of pressing forming. The ball milling time is 2 - 4 hours, and the ball milling medium is stainless steel balls;

[0008] S2. Powder mixing: Mix the pretreated diamond powder and cemented carbide powder evenly according to the designed ratio. The mixing time is 1 - 2 hours. Add an appropriate amount of alcohol as a wetting agent during the mixing process. Adjust the mixing ratio of diamond and cemented carbide according to the performance requirements of different parts of the pick to achieve gradient distribution;

[0009] S3. Place the mold equipment in batches. Design the pick into three parts, namely the cutting part, the transition part, and the matrix part. The gradient ratios of each part are as follows:

[0010] Cutting part: The weight ratio of diamond powder is 60%, and the weight ratio of cemented carbide powder is 40%;

[0011] Transition part: The weight ratio of diamond powder is 40%, and the weight ratio of cemented carbide powder is 60%;

[0012] Matrix part: The weight ratio of diamond powder is 20%, and the weight ratio of cemented carbide powder is 80%;

[0013] Place the mixed powders with different ratios in the mold body in batches. First, place the powder of the cutting part, then the transition part, and finally the matrix part. After each batch of powder is placed, use a hydraulic press to flatten the powder once to make the powder fill evenly and remove air;

[0014] S4. Compression molding and demolding. Use a hydraulic press to perform the final compression molding on the powder in the mold body. The pressing pressure is 500 - 700 MPa, and the pressure holding time is 5 - 10 minutes to obtain a preform of the pick. During the pressing process, ensure that the powders of each part are in close contact to form a firm overall structure; by controlling the contraction of the electric push rod, the linkage plate and the ejector rod can be driven to move upward, and then the ejector block is pushed to move upward. The preformed pick in the mold body can be ejected from the mold body through the upward movement of the ejector block to complete demolding;

[0015] S5. Sintering treatment. Send the preform into a sintering furnace and sinter it in an environment with a temperature of 1300 - 1500 °C and a pressure of 10 - 20 MPa for 2 - 4 hours to form a gradient structure of diamond and cemented carbide. A protective atmosphere is used during the sintering process to prevent oxidation;

[0016] S6. Machining. Perform precision machining on the sintered pick, including turning, grinding, and polishing, to ensure the dimensional accuracy and surface finish of the pick. The machining tolerance is ±0.01 mm;

[0017] S7. Surface treatment. Perform surface strengthening treatment on the machined pick using laser cladding technology to improve its wear resistance and impact resistance. The thickness of the surface treatment layer is 10 - 30 microns to obtain a finished pick;

[0018] S8. Quality inspection. Perform strict quality inspection on the finished pick, including hardness testing, wear resistance testing, impact resistance testing, and dimensional accuracy detection;

[0019] S9. Packaging and storage. Vacuum package the qualified picks and store them in an environment with a temperature of 20 ± 5 °C and a humidity ≤ 50%.

[0020] Preferably, the mold equipment includes a mold base frame, a mold body, an electric push rod, a linkage plate, a ejector rod, a ejector block and a scale dividing line. The mold body is fixedly connected to the inner side of the plate of the mold base frame. An electric push rod is installed in the right port of the plate of the mold base frame. The lower end of the driving rod of the electric push rod is fixedly connected to the linkage plate. The upper side of the left end of the linkage plate is fixedly connected to the ejector rod, and the ejector rod is located directly below the mold body. The upper end of the ejector rod is fixedly connected to the ejector block located inside the lower opening of the mold body. A pair of scale dividing lines arranged vertically are provided inside the mold body.

[0021] Preferably, in the pressing and forming and demolding steps, the mold body needs to be arranged directly below the punching head of the hydraulic press, and the diameter of the punching head of the hydraulic press should be precisely matched with the inner cavity diameter of the mold body.

[0022] Preferably, the inner cavity of the mold body is composed of a cylindrical cavity and several conical angle grooves arranged at equal angles. In the pressing and forming and demolding steps, the shape and structure of the inner cavity of the mold body are matched with the shape and structure of the finished pick. The length dimension of the ejector rod is greater than the length dimension of the mold body, and there is a spacing between the scale dividing lines.

[0023] Preferably, the upper end surface of the ejector block and the lower inner wall of the mold body are set with smooth transition, and the lower end surface of the linkage plate and the lower end surface of the support rod of the mold base frame are on the same plane.

[0024] Preferably, the cemented carbide is tungsten carbide-cobalt cemented carbide, the material of the mold body is high-strength alloy steel, and the surface of the mold body must be hardened.

[0025] Preferably, the protective atmosphere used in the sintering treatment step is argon, and a high-precision CNC machine tool is used for processing in the machining step, and a coolant needs to be used during the processing.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] In the present invention, through processes such as raw material selection and pretreatment, powder mixing, batch placement into die equipment, pressing and forming, demolding, sintering treatment, machining, surface treatment, and quality inspection, the gradient composite manufacturing of the taper angle self-sharpening high-strength mining pick is realized. The different parts of the pick adapt to the specific requirements of different parts through the gradient change of material properties, significantly improving the wear resistance and impact resistance of the pick. Specifically, the material ratios of the cutting part, transition part, and matrix part are optimized to meet the performance requirements of each part in actual work; the cutting part uses a high proportion of diamond powder to ensure excellent wear resistance when directly contacting the ore; the transition part uses a medium proportion of diamond powder and cemented carbide powder to balance wear resistance and toughness; while the matrix part mainly uses cemented carbide powder to provide overall strength and impact resistance. This gradient design enables the pick to exert the maximum performance advantages in different parts. In addition, the cutting edge of the taper angle self-sharpening high-strength mining pick is designed to be conical. This geometric shape causes the conical edge of the pick to generate friction and impact with the rock during the cutting process. Even if wear occurs, this dynamic action will cause the worn material at the edge to fall off, exposing a new sharp edge. This mechanism enables the pick to continuously maintain high cutting performance under harsh working conditions, solving the problem that the wear resistance of existing mining picks is average and frequent replacement is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of the finished pick of the present invention;

[0029] Figure 2 is a schematic structural diagram of the die equipment of the present invention;

[0030] Figure 3 For the present invention Figure 2 is a schematic bottom view structure diagram;

[0031] Figure 4 For the present invention Figure 2 is a schematic top view structure diagram;

[0032] Figure 5 is a schematic structural diagram of the manufacturing process flow of the present invention.

[0033] In the figure: 11, die base frame; 12, die body; 13, electric push rod; 14, linkage plate; 15, ejector rod; 16, ejector block; 17, scale dividing line. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] Please refer to Figures 1-5 , the present invention provides a technical solution:

[0035] The taper angle self-sharpening high-strength mining pick and its gradient manufacturing method include the following steps:

[0036] S1. Raw material selection and pretreatment: Select high-purity diamond powder and cemented carbide powder as the main raw materials. The average particle size of the diamond powder is 5 - 10 microns, and the particle size of the cemented carbide powder is 1 - 5 microns. Perform ball milling pretreatment on the diamond powder and cemented carbide powder to improve the fluidity of the powder and the density of pressing forming. The ball milling time is 2 - 4 hours, and the ball milling medium is stainless steel balls.

[0037] S2. Powder mixing: Mix the pretreated diamond powder and cemented carbide powder evenly according to the designed ratio. The mixing time is 1 - 2 hours. Add an appropriate amount of alcohol as a wetting agent during the mixing process. Adjust the mixing ratio of diamond and cemented carbide according to the performance requirements of different parts of the pick to achieve gradient distribution.

[0038] S3. Batchwise placement into the mold equipment: Design the pick into three parts, namely the cutting part, the transition part, and the substrate part. The gradient ratios of each part are as follows:

[0039] Cutting part: The weight ratio of diamond powder is 60%, and the weight ratio of cemented carbide powder is 40%.

[0040] Transition part: The weight ratio of diamond powder is 40%, and the weight ratio of cemented carbide powder is 60%.

[0041] Substrate part: The weight ratio of diamond powder is 20%, and the weight ratio of cemented carbide powder is 80%.

[0042] Batchwise place the mixed powder with different ratios into the mold body 12. First, place the powder of the cutting part, then the transition part, and finally the substrate part. After placing each batch of powder, use a hydraulic press to flatten the powder once to make the powder fill evenly and remove air.

[0043] S4. Pressing forming and demoulding: Use a hydraulic press to perform the final pressing forming on the powder in the mold body 12. The pressing pressure is 500 - 700 MPa, and the pressure holding time is 5 - 10 minutes to obtain the pick preform. During the pressing process, ensure that the powders of each part are in close contact to form a firm overall structure. By controlling the contraction of the electric push rod 13, the linkage plate 14 and the ejector rod 15 can be driven to move upward, and then the ejector block 16 is pushed to move upward. Through the upward movement of the ejector block 16, the pick preform formed by pressing in the mold body 12 can be ejected from the mold body 12 to complete demoulding.

[0044] S5. Sintering treatment: Send the preform into a sintering furnace and sinter it in an environment with a temperature of 1300 - 1500 °C and a pressure of 10 - 20 MPa. The sintering time is 2 - 4 hours to form a gradient structure of diamond and cemented carbide. Use a protective atmosphere during the sintering process to prevent oxidation.

[0045] S6. Machining: Precision machining the sintered picks, including turning, grinding, and polishing, to ensure the dimensional accuracy and surface finish of the picks, with a machining tolerance of ±0.01 mm;

[0046] S7. Surface treatment: Surface strengthening treatment of the machined picks using laser cladding technology to improve their wear resistance and impact resistance, with a surface treatment layer thickness of 10 - 30 microns, obtaining the finished picks;

[0047] S8. Quality inspection: Conducting strict quality inspections on the finished picks, including hardness test HV≥1500, wear resistance test with wear rate ≤0.1 g / m 2 , impact resistance test with impact strength ≥10 kJ / m 2 and dimensional accuracy inspection;

[0048] S9. Packaging and storage: Vacuum packaging the qualified picks and storing them in an environment with a temperature of 20±5°C and a humidity ≤50%.

[0049] The die equipment includes a die base frame 11, a die body 12, an electric push rod 13, a linkage plate 14, a ejector rod 15, an ejector block 16, and a scale dividing line 17. The inner side of the plate of the die base frame 11 is fixedly connected with the die body 12. An electric push rod 13 is installed inside the right port of the plate of the die base frame 11. The lower end of the driving rod of the electric push rod 13 is fixedly connected with the linkage plate 14. The upper side of the left end of the linkage plate 14 is fixedly connected with the ejector rod 15, and the ejector rod 15 is located directly below the die body 12. The upper end of the ejector rod 15 is fixedly connected with the ejector block 16 inside the lower opening of the die body 12. Inside the die body 12, there are a pair of scale dividing lines 17 arranged vertically. The provided die equipment can be used in the processes of pressing and demolding to store the powder ratios of the cutting, transition, and matrix parts, cooperate with a hydraulic press to press them into prefabricated parts, and can demold the prefabricated parts after they are formed; during the processes of pressing and demolding, the die body 12 needs to be set directly below the punching head of the hydraulic press, and the diameter of the punching head of the hydraulic press should be precisely matched with the inner cavity diameter of the die body 12. Through this setting, the punching head of the hydraulic press can fully press into the die body 12 to press the powder in the die body 12 into a pick prefabricated part; the inner cavity of the die body 12 consists of a cylindrical cavity and several conical grooves arranged at equal angles. During the processes of pressing and demolding, the shape structure of the inner cavity of the die body 12 is matched with the shape structure of the finished pick. Through this setting, the finished picks made through each process have several conical structures. The length dimension of the ejector rod 15 is greater than the length dimension of the die body 12. Through this setting, the ejector rod 15 cooperating with the ejector block 16 can completely eject the pressed prefabricated part from the die body 12. There is a spacing between the scale dividing lines 17. Through this setting, it serves as an indication line to help the staff place the corresponding amount of powder ratio in batches; the upper end surface of the ejector block 16 and the lower inner wall of the die body 12 are set with a smooth transition. Through this setting, the pressing of the pick prefabricated part is not affected by the interference of the ejector block 16. The lower end surface of the linkage plate 14 and the lower end surface of the support rod of the die base frame 11 are set on the same plane. Through this setting, the linkage plate 14 is in contact with the ground to prevent the ejector block 16 from moving downward and keep the ejector block 16 in its position under normal conditions; the cemented carbide uses tungsten carbide-cobalt cemented carbide, which is famous for its extremely high hardness, excellent wear resistance, and excellent red hardness, and is very suitable for manufacturing cutting tools and wear-resistant parts. After being mixed with diamond powder and undergoing a sintering process, this cemented carbide can provide the necessary toughness for the pick, thereby enhancing its durability in an impact and wear environment while maintaining the cutting performance of the superhard material. The material of the die body 12 is high-strength alloy steel, and the surface of the die body 12 must be hardened. Through this setting, the strength of the die body 12 is ensured, and it is ensured that the die body 12 will not deform during the processes of pressing and demolding; the protective atmosphere used in the sintering treatment step is argon. Through this setting, oxidation is prevented. During the machining step, a high-precision CNC machine tool is used for machining, and a coolant needs to be used during the machining process. Through this setting, thermal deformation can be reduced.

[0050] In this article, specific examples are used to illustrate the principles and implementation modes of the present invention. The descriptions of the above examples are only used to help understand the method and its core idea of the present invention. The above is only the preferred implementation mode of the present invention. It should be noted that due to the limitation of literal expression and objectively infinite specific structures, for those of ordinary skill in the art, without departing from the principles of the present invention, several improvements, retouches or changes can also be made, or the above technical features can be combined in an appropriate manner; these improvements, retouches, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, shall all be regarded as the protection scope of the present invention.

Claims

1. The cone angle self-sharpening high-strength mining pick and its gradient manufacturing method are characterized in that It includes the following steps: S1. Raw material selection and pretreatment: Select high-purity diamond powder and cemented carbide powder as the main raw materials. The average particle size of the diamond powder is 5 - 10 microns, and the particle size of the cemented carbide powder is 1 - 5 microns. Perform ball milling pretreatment on the diamond powder and cemented carbide powder. The ball milling time is 2 - 4 hours, and the ball milling medium is stainless steel balls; S2. Powder mixing: Mix the pretreated diamond powder and cemented carbide powder evenly according to the designed ratio. The mixing time is 1 - 2 hours. Add an appropriate amount of alcohol as a wetting agent during the mixing process. Adjust the mixing ratio of diamond and cemented carbide according to the performance requirements of different parts of the pick to achieve a gradient distribution; S3. Place into the die equipment in batches: Design the pick into three parts, namely the cutting part, the transition part, and the matrix part. The gradient ratios of each part are as follows: Cutting part: The weight ratio of diamond powder is 60%, and the weight ratio of cemented carbide powder is 40%; Transition part: The weight ratio of diamond powder is 40%, and the weight ratio of cemented carbide powder is 60%; Matrix part: The weight ratio of diamond powder is 20%, and the weight ratio of cemented carbide powder is 80%; Place the mixed powder with different ratios into the die body (12) in batches. First, place the powder of the cutting part, then the transition part, and finally the matrix part. After placing each batch of powder, use a hydraulic press to flatten the powder once to make the powder fill evenly and remove air; S4. Compression molding and demolding: Use a hydraulic press to perform final compression molding on the powder in the die body (12). The pressing pressure is 500 - 700 MPa, and the pressure holding time is 5 - 10 minutes to obtain a preform of the pick. During the pressing process, ensure that the powders of each part are in close contact to form a firm overall structure; By controlling the contraction of the electric push rod (13), the linkage plate (14) and the ejector rod (15) can be driven to move upward, and then the ejector block (16) is pushed to move upward. Through the upward movement of the ejector block (16), the pick preform molded in the die body (12) can be ejected from the die body (12) to complete demolding; S5. Sintering treatment: Send the preform into a sintering furnace and sinter it in an environment with a temperature of 1300 - 1500 °C and a pressure of 10 - 20 MPa. The sintering time is 2 - 4 hours to form a gradient structure of diamond and cemented carbide. A protective atmosphere is used during the sintering process; S6. Machining: Perform precision machining on the sintered pick, including turning, grinding, and polishing to ensure the dimensional accuracy and surface finish of the pick. The machining tolerance is ±0.01 mm; S7. Surface treatment: Perform surface strengthening treatment on the machined pick. The thickness of the surface treatment layer is 10 - 30 microns to obtain a finished pick; S8. Quality inspection: Conduct strict quality inspections on the finished pick, including hardness testing (HV≥1500), wear resistance testing (wear rate ≤ 0.1 g / m 2 ), impact resistance testing (impact strength ≥ 10 kJ / m 2 ), and dimensional accuracy inspection; S9. Packaging and storage: Vacuum package the qualified picks and store them in an environment with a temperature of 20 ± 5 °C and a humidity ≤ 50%.

2. The taper angle self-sharpening high-strength mining pick and its gradient manufacturing method according to claim 1, characterized in that: The mold equipment includes a mold base frame (11), a mold body (12), an electric push rod (13), a linkage plate (14), a ejector rod (15), a ejector block (16) and a scale dividing line (17). The inner side of the plate of the mold base frame (11) is fixedly connected with the mold body (12). The electric push rod (13) is installed in the right port position of the plate of the mold base frame (11). The lower end of the driving rod of the electric push rod (13) is fixedly connected with the linkage plate (14). The upper side of the left end of the linkage plate (14) is fixedly connected with the ejector rod (15), and the ejector rod (15) is located directly below the mold body (12). The upper end of the ejector rod (15) is fixedly connected with the ejector block (16) inside the lower opening of the mold body (12). A pair of scale dividing lines (17) arranged vertically are provided inside the mold body (12).

3. The taper angle self-sharpening high-strength mining pick and its gradient manufacturing method according to claim 1, characterized in that: In the pressing and forming and demolding steps, the mold body (12) needs to be arranged directly below the punching head of the hydraulic press, and the diameter of the punching head of the hydraulic press should be precisely matched with the inner cavity diameter of the mold body (12).

4. The taper angle self-sharpening high-strength mining pick according to claim 2 and its gradient manufacturing method, characterized in that: The inner cavity of the mold body (12) is composed of a cylindrical cavity and several conical grooves arranged at equal angles. In the pressing and forming and demolding steps, the shape and structure of the inner cavity of the mold body (12) are matched with the shape and structure of the finished pick. The length dimension of the ejector rod (15) is greater than the length dimension of the mold body (12), and there is a spacing between the scale dividing lines (17).

5. The taper angle self-sharpening high-strength mining pick according to claim 2 and its gradient manufacturing method, characterized in that: The upper end surface of the ejector block (16) and the lower inner wall of the mold body (12) are set with smooth transition. The lower end surface of the linkage plate (14) and the lower end surface of the support rod of the mold base frame (11) are set on the same plane.

6. The conical angle self-sharpening high-strength mining pick and its gradient manufacturing method according to claim 2, characterized in that: The cemented carbide adopts tungsten carbide-cobalt cemented carbide. The material of the mold body (12) is high-strength alloy steel, and the surface of the mold body (12) must be hardened.

7. The taper angle self-sharpening high-strength mining pick and its gradient manufacturing method according to claim 1, characterized in that: The protective atmosphere used in the sintering treatment step is argon. In the machining step, a high-precision CNC machine tool is used for machining, and a coolant is required during the machining process.

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