Aluminum alloy drill rod and preparation process thereof

Abstract

The invention provides an aluminum alloy drill rod and a preparation process thereof. According to the aluminum alloy drill rod, the advantages of TiC and B4C ceramic particle reinforced aluminum matrix composites are coupled, double-gradient optimization is conducted on distribution of the two ceramic particles, and the performance advantages that the inner layer of the functional structure of the aluminum alloy drill rod is good in toughness, the outer layer is high in abrasion resistance, and the overall high-temperature mechanical property and the damping property are good are achieved; according to the double-phase ceramic particle gradient enhanced aluminum alloy drill rod, the functional structure of the outer surface is discontinuously distributed, friction stress release and friction heat diffusion between the functional structure layer and slurry in the rotating process are facilitated, and the service life of the aluminum alloy drill rod is prolonged. According to the spiral functional structure layer embedded in the surface of the drill rod, the strength of the drill rod is improved, the rigidity of the drill rod is enhanced, bending of the drill rod in the drilling process is reduced, meanwhile, the abrasion resistance of the drill rod is enhanced, the service life of the drill rod can be greatly prolonged, the possibility that the drill rod is broken is reduced, and the drilling efficiency is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of drill rods, and in particular to an aluminum alloy drill rod and a preparation process thereof. Background Art

[0002] With the increasing demand for drilling and mining of deep wells, ultra-deep wells, horizontal wells, and extended-reach wells, traditional steel drill pipes are gradually becoming ineffective in the face of high-content H2O2 in deep and ultra-deep wells. 2 S and CO 2 The environment is prone to stress corrosion failure, and the steel drill pipe is heavy and has high transportation costs. In contrast, the aluminum-based drill pipe is light, has high specific strength, good corrosion resistance, and is non-magnetic, so it can use measurement while drilling tools. For drilling rigs with the same large hook load capacity, using aluminum alloy drill pipes instead of ordinary steel drill pipes can greatly reduce the power consumption and time of drilling operations and improve the drilling capacity of the drilling rig. However, aluminum alloys have low hardness and poor wear resistance. In drilling where high-speed friction occurs all the time, the surface of the aluminum drill pipe needs to be strengthened. The usual methods are: micro-arc oxidation film method, flame spraying method, or directly using aluminum-based composite materials to make drill pipes. Among them, the micro-arc oxidation film and the spray strengthening layer have the problem that the reinforcement layer is easy to fall off, and the comprehensive use of aluminum-based composite materials to manufacture drill pipe materials has problems such as high cost and reduced fatigue performance. Therefore, a lightweight aluminum-based drill pipe with low cost, long life, repairability, stable corrosion resistance and wear resistance is of great significance to the further development of the drilling and mining industry.

[0003] The Chinese invention patent number is CN107043901B, the publication date is 2019.01.08, and the name of the invention is "basalt fiber and ceramic particles mixed aluminum alloy drill pipe material and preparation method thereof". A nano-ceramic particle mixed basalt fiber reinforced aluminum alloy drill pipe material is developed by combining vacuum hot pressing sintering and medium-temperature extrusion. Although the invention uses nano-ceramic particles to enhance the uniformity of basalt fiber distribution in the matrix, enhance the strength and wear resistance of the material, and has good serviceability at high temperatures. However, the production and maintenance costs are high and lack market competitiveness.

[0004] The Chinese invention patent number is CN10475144A, the publication date is July 15, 2015, and the invention is titled "A method for preparing a micro-arc oxidation film doped with ceramic powder on the surface of an aluminum alloy drill rod". The method adds ceramic powder that has undergone targeted induction treatment to the micro-arc oxidation solution to form a metallurgical bond between the ceramic powder and the micro-arc oxidation ceramic film that has been formed on the aluminum alloy drill rod. The patent improves the density and hardness of the micro-arc oxidation ceramic film, which is beneficial to improving the wear resistance of the drill rod surface, but does not fundamentally solve the problem of the easy detachment of the micro-arc oxidation film.

[0005] The Chinese invention patent number is CN117845160A, the publication date is 2024.04.09, and the name of the invention is "A method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of an aluminum alloy drill pipe". The Al86Ni6.75Co2.25Y3.25La1.75 coating prepared by low-temperature supersonic flame spraying technology provides high wear resistance and excellent corrosion resistance, but the amorphous coating has limited thickness and is very brittle. It is easy to crack and fall off during use, and cannot fundamentally improve the service life of the aluminum alloy drill pipe.

[0006] Based on the defects of the current drill pipe, it is necessary to improve it. Summary of the invention

[0007] In view of the deficiencies of existing aluminum-based drill rods in terms of materials, structure, performance and manufacturing process, the purpose of the present invention is to provide an aluminum alloy drill rod and a preparation process thereof to solve the defects of the existing drill rods.

[0008] The present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides an aluminum alloy drill pipe, comprising:

[0010] Drill pipe;

[0011] A functional structural layer, spirally embedded on the surface of the drill rod;

[0012] Wherein, one end surface of the functional structure layer is embedded in the drill rod, and the other end surface is flush with the surface of the drill rod;

[0013] The functional structure layer includes a matrix, TiC ceramic particles, B 4 C ceramic particles;

[0014] Wherein, the volume fraction of the TiC ceramic particles increases with the increase of the thickness of the functional structure layer from the end surface embedded in the drill rod to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer;

[0015] When the thickness of the functional structure layer exceeds 1 / 2 to 5 / 8 of the thickness of the functional structure layer, the volume fraction of the TiC ceramic particles decreases as the thickness of the functional structure layer increases. 4 The volume fraction of C ceramic particles increases with the thickness of the functional structure layer.

[0016] Preferably, the volume fraction of the TiC ceramic particles increases from 0% to 20-30% as the thickness of the functional structure layer increases from the end surface embedded in the drill rod to the 1 / 2-5 / 8 position of the thickness of the functional structure layer, and the B 4 The volume fraction of C ceramic particles is 0%;

[0017] When the thickness of the functional structure layer exceeds 1 / 2 to 5 / 8 of the thickness of the functional structure layer, the volume fraction of the TiC ceramic particles decreases from 20 to 30% to 3 to 5% as the thickness of the functional structure layer increases. 4 The volume fraction of C ceramic particles increases from 0% to 10-20% as the thickness of the functional structure layer increases.

[0018] Preferably, the functional structure layer is from the end surface embedded in the drill pipe to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer, and the functional structure layer includes a plurality of stacked first sub-functional structure layers, each of which has B 4 The volume fraction of TiC ceramic particles is 0%; wherein the volume fraction of TiC ceramic particles in the first sub-functional structural layer farthest from the drill pipe surface is 0%, and the volume fraction difference of TiC ceramic particles in any two adjacent first sub-functional structural layers is 3-5%;

[0019] The thickness of the functional structure layer is from 1 / 2 to 5 / 8 of the thickness of the functional structure layer to the end face flush with the surface of the drill rod, and the functional structure layer includes a plurality of stacked second sub-functional structure layers; wherein the volume fraction of TiC ceramic particles in the second sub-functional structure layer farthest from the surface of the drill rod is 15-25%, B 4 The volume fraction of C ceramic particles is 3-4%, the volume fraction difference of TiC ceramic particles in any two adjacent second sub-functional structural layers is 4-6%, 4 The volume fraction difference of C ceramic particles is 2-4%.

[0020] Preferably, the particle size of the TiC ceramic particles is 25 to 60 μm;

[0021] B 4 The particle size of C ceramic particles is 45 to 300 μm.

[0022] Preferably, the drill rod comprises:

[0023] Drill pipe body;

[0024] Drill pipe joints, which are respectively located at two ends of the drill pipe body, and the drill pipe joints are connected to the drill pipe body by threads;

[0025] The functional structural layers are respectively spirally embedded on the surfaces of the drill pipe body and the drill pipe joint.

[0026] Preferably, the end surface of the functional structure layer flush with the surface of the drill pipe is also provided with a capping layer.

[0027] Preferably, the material of the drill pipe body is Al-Mg-Sc-Zr alloy;

[0028] The material of the substrate is Al-Mg alloy;

[0029] The material of the capping layer is Al-Mg alloy;

[0030] The material of the drill pipe joint is Al-Zn alloy;

[0031] The thickness of the functional structural layer is 45-50% of the wall thickness of the drill pipe body.

[0032] In a second aspect, the present invention further provides a process for preparing the aluminum alloy drill pipe, comprising the following steps:

[0033] preparing a drill pipe body;

[0034] A first groove arranged in a spiral shape is processed on the surface of the drill pipe body, wherein the first groove is adapted to the functional structure layer;

[0035] Prepare drill pipe joints;

[0036] A second groove arranged in a spiral shape is processed on the surface of the drill rod joint, wherein the second groove is adapted to the functional structure layer;

[0037] Determine the additive manufacturing deposition path based on the structure of the functional structural layer;

[0038] TiC ceramic particles, B 4 C ceramic particles are placed in two powder feeders with independent powder feeding channels, and the two powder feeding channels are connected to the wire-powder synchronous deposition composite welding gun head;

[0039] Install the alloy welding wire corresponding to the substrate on the wire feeder;

[0040] Arc additive deposition and control of TiC ceramic particles, B 4 The powder feeding rate of C ceramic particles is used to print the functional structure layer in the first groove and the second groove.

[0041] Preferably, the process parameters controlled during arc additive deposition are: deposition current of 90-110A, fuse speed of 5.0-6.0m / min, arc swing amplitude of 4-10mm, arc swing frequency of 2-5Hz, capture rate of TiC ceramic particles by the molten pool of 60-70%, and capture rate of B by the molten pool of 100%. 4 The capture rate of C ceramic particles is 30-40%.

[0042] Preferably, the drill pipe body is prepared by an extrusion molding process; the drill pipe joint is prepared by an extrusion molding process; during arc additive deposition, the width of a single deposition layer is 5 to 20 mm, and the thickness of each layer is 0.5 to 2 mm.

[0043] The aluminum alloy drill rod and its preparation process of the present invention have the following beneficial effects compared with the prior art:

[0044] 1. The aluminum alloy drill rod of the present invention is innovative in that it couples TiC and B 4 C two ceramic particle reinforced aluminum matrix composites, TiC and B 4 The distribution of the two types of ceramic particles C has been optimized with a double gradient, achieving the performance advantages of good toughness of the inner layer of the aluminum alloy drill pipe functional structure, strong wear resistance of the outer layer, and excellent overall high-temperature mechanical properties and shock absorption; the dual-phase ceramic particle gradient-enhanced aluminum alloy drill pipe of the present invention has a non-continuous distribution of the functional structure of the outer surface, which is beneficial to the release of friction stress and friction heat diffusion between the functional structure layer and the mud during rotation, thereby improving the life of the aluminum alloy drill pipe. The spiral functional structure layer embedded in the surface of the drill pipe of the present invention improves the strength of the drill pipe, enhances the rigidity of the drill pipe, reduces the bending of the drill pipe during drilling, and enhances the wear resistance of the drill pipe, which can greatly improve the service life of the drill pipe, reduce the possibility of the drill pipe breaking, and effectively improve the drilling efficiency;

[0045] 2. The preparation process of the aluminum alloy drill rod of the present invention is innovative in that it breaks the traditional way of strengthening the overall surface of the aluminum-based drill rod, and adopts the method of silk-powder synchronous deposition to locally strengthen the surface of the drill rod, so that the functional structure is metallurgically combined with the aluminum-based drill rod and is not easy to fall off, while reducing the abuse of the reinforcement material; the aluminum alloy drill rod with dual-phase ceramic particle gradient reinforcement prepared by the present invention can also be repaired by the arc additive manufacturing process of silk-powder synchronous deposition after the friction surface and functional structure are worn, which can greatly extend the service life of the drill rod and further reduce the product cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 It is a schematic structural diagram of the aluminum alloy drill rod of the present invention;

[0048] Figure 2 is a cross-sectional view of the aluminum alloy drill rod of the present invention;

[0049] Figure 3 is a schematic structural diagram of a first joint of the present invention;

[0050] Figure 4 is a schematic structural diagram of a second joint of the present invention;

[0051] Figure 5 It is a schematic structural diagram of the functional structural layer of the present invention;

[0052] Figure 6 It is a schematic structural diagram of the functional structural layer on the tube wall of the drill pipe body of the present invention;

[0053] Figure 7 This is a schematic diagram of the structure of providing a cover layer on the functional structure layer of the present invention;

[0054] Figure 8 This is a schematic diagram showing that the functional structural layer of the present invention includes a plurality of first sub-functional structural layers stacked in layers and a plurality of second sub-functional structural layers stacked in layers. DETAILED DESCRIPTION

[0055] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] In the description of the present invention, it should be understood that the directions or positions indicated by “upper” and the like are based on the directions or positions shown in the accompanying drawings, or are the directions or positions in which the product of the invention is usually placed when in use, or are directions or positions commonly understood by those skilled in the art. These directions or positions are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0057] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0058] The order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0059] The present application embodiment provides an aluminum alloy drill rod, such as Figures 1 to 8 As shown, including:

[0060] Drill pipe;

[0061] A functional structural layer, spirally embedded on the surface of the drill rod;

[0062] Wherein, one end surface of the functional structure layer is embedded in the drill rod, and the other end surface is flush with the surface of the drill rod;

[0063] The functional structure layer includes a matrix, TiC ceramic particles, B 4 C ceramic particles;

[0064] Among them, the volume fraction of TiC ceramic particles increases with the increase of the thickness of the functional structure layer from the end surface embedded in the drill pipe to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer;

[0065] When the thickness of the functional structure layer exceeds 1 / 2 to 5 / 8 of the thickness of the functional structure layer, the volume fraction of the TiC ceramic particles decreases as the thickness of the functional structure layer increases. 4 The volume fraction of C ceramic particles increases with the thickness of the functional structure layer.

[0066] The aluminum alloy drill rod of the present invention comprises a drill rod 1 and a functional structure layer 2, wherein the functional structure layer 2 is spirally arranged on the circumference of the drill rod 1; specifically, a groove is spirally arranged on the circumference of the tube wall of the drill rod 1, one end face of the functional structure layer is embedded in the groove, and the other end face is flush with the circumference of the tube wall of the drill rod 1; the functional structure layer 2 comprises a matrix, TiC ceramic particles, B 4 C ceramic particles; the functional structure layer is from the end surface embedded in the drill pipe to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer; for details, refer to Figure 6 As shown, Figure 6 A to B is the direction from the end face of the functional structure layer 2 embedded in the drill pipe to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer. In the direction from A to B, the volume fraction of TiC ceramic particles increases with the increase of the thickness of the functional structure layer. When the thickness of the functional structure layer exceeds 1 / 2 to 5 / 8 of the thickness of the functional structure layer, that is, from the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer to the end face flush with the wall surface of the drill pipe 1, that is, Figure 1 From B to C, the volume fraction of TiC ceramic particles decreases with the increase of the thickness of the functional structure layer; that is, the volume fraction of TiC ceramic particles reaches the maximum value at the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer 2; when the thickness of the functional structure layer 2 is from the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer to the end face flush with the wall surface of the drill pipe 1, B 4The volume fraction of C ceramic particles increases with the thickness of the functional structure layer; again refer to Figure 6 As shown in the figure, B to C are from the position where the thickness of the functional structure layer 2 is 1 / 2 to 5 / 8 of the thickness of the functional structure layer to the end surface flush with the wall surface of the drill pipe 1. In the direction from B to C, the volume fraction of TiC ceramic particles decreases with the increase of the thickness of the functional structure layer. 4 The volume fraction of C ceramic particles increases with the thickness of the functional structure layer; the aluminum alloy drill rod of the present invention is innovative in that TiC and B are coupled 4 C two ceramic particle reinforced aluminum matrix composites, TiC and B 4 The distribution of the two types of ceramic particles C has been optimized with dual gradients, achieving the performance advantages of good toughness of the inner layer of the aluminum alloy drill pipe functional structure, strong wear resistance of the outer layer, and excellent overall high-temperature mechanical properties and shock absorption; the aluminum alloy drill pipe with dual-phase ceramic particle gradient enhancement of the present invention has a discontinuous distribution of the outer surface functional structure, which is conducive to the release of friction stress and friction heat diffusion between the functional structure layer and the mud during rotation, and improves the life of the aluminum alloy drill pipe. The spiral functional structure layer embedded in the surface of the drill pipe of the present invention improves the strength of the drill pipe, enhances the rigidity of the drill pipe, reduces the bending of the drill pipe during drilling, and enhances the wear resistance of the drill pipe, which can greatly improve the service life of the drill pipe, reduce the possibility of drill pipe breakage, and effectively improve drilling efficiency.

[0067] In some embodiments, the functional structure layer is embedded in the drill pipe end surface to the 1 / 2 to 5 / 8 position of the thickness of the functional structure layer. At this time, the functional structure layer 2 includes a matrix and TiC ceramic particles. The volume fraction of the TiC ceramic particles increases from 0% to 20 to 30% as the thickness of the functional structure layer increases. 4 The volume fraction of C ceramic particles is 0%, and the rest is the matrix;

[0068] When the thickness of the functional structure layer exceeds 1 / 2 to 5 / 8 of the thickness of the functional structure layer, specifically, when the thickness of the functional structure layer 2 is 1 / 2 to 5 / 8 of the thickness of the functional structure layer to the end surface flush with the wall surface of the drill pipe 1, at this time, the functional structure layer 2 includes a matrix, TiC ceramic particles, B 4 The volume fraction of C ceramic particles and TiC ceramic particles decreases from 20-30% to 3-5% with the increase of the thickness of the functional structure layer. 4 The volume fraction of C ceramic particles increases from 0% to 10-20% as the thickness of the functional structure layer increases, and the rest is the matrix.

[0069] In some embodiments, reference Figure 8As shown, the functional structure layer extends from the end face embedded in the drill rod to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer. The functional structure layer 2 includes a plurality of first sub-functional structure layers 21 stacked together, wherein the volume fraction of TiC ceramic particles in the first sub-functional structure layer 21 farthest from the pipe wall surface of the drill rod 1 is 0%, and the difference in volume fraction of TiC ceramic particles in any two adjacent first sub-functional structure layers is 3 to 5%, and the volume fraction of TiC ceramic particles in the first sub-functional structure layer 21 closest to the pipe wall surface of the drill rod 1 is 20 to 30%, and the difference in volume fraction of TiC ceramic particles in any two adjacent first sub-functional structure layers 21 is 3 to 5%.

[0070] In some embodiments, reference Figure 8 As shown, the thickness of the functional structure layer is from 1 / 2 to 5 / 8 of the thickness of the functional structure layer to the end face flush with the wall surface of the drill pipe 1, and the functional structure layer 2 includes a plurality of second sub-functional structure layers 22 stacked in layers; wherein the volume fraction of TiC ceramic particles in the second sub-functional structure layer farthest from the wall surface of the drill pipe 1 is 15-25%, B 4 The volume fraction of TiC ceramic particles is 3-4%, the volume fraction of TiC ceramic particles in the second sub-functional structural layer closest to the wall surface of the drill pipe 1 is 3-5%, and the volume fraction of B 4 The volume fraction of TiC ceramic particles is 10-20%; the volume fraction difference of TiC ceramic particles in any two adjacent second sub-functional structural layers 22 is 4-6%, 4 The volume fraction difference of C ceramic particles is 2-4%.

[0071] In the above embodiment, the functional structural layer 2 includes a matrix and TiC ceramic particles. The volume fraction of the TiC ceramic particles is calculated as follows: the volume of the TiC ceramic particles is obtained by dividing the mass of the TiC ceramic particles by their density. The volume of the melted and deposited Al-Mg alloy welding wire is the volume of the matrix. The volume of the TiC ceramic particles is divided by the sum of the volumes of the TiC ceramic particles and the matrix to obtain the volume fraction of the TiC ceramic particles.

[0072] In the above embodiment, the functional structure layer 2 includes a matrix, TiC ceramic particles, B 4 The volume fraction of C ceramic particles and TiC ceramic particles is calculated as follows: the volume of TiC ceramic particles is obtained by dividing the mass of TiC ceramic particles by their density. The volume of the melted and deposited Al-Mg alloy welding wire is the volume of the matrix. 4 The mass of the ceramic particle C is divided by its density to obtain B 4 The volume of C ceramic particles is calculated by dividing the volume of TiC ceramic particles by the volume of TiC ceramic particles, B 4 The sum of the volumes of C ceramic particles and the matrix is ​​the volume fraction of TiC ceramic particles; B4 The volume fraction of C ceramic particles is calculated by using B 4 The volume of C ceramic particles is divided by the volume of TiC ceramic particles, B 4 The sum of the volumes of the C ceramic particles and the matrix is ​​B 4 C is the volume fraction of ceramic particles.

[0073] In some embodiments, the particle size of the TiC ceramic particles is 25 to 60 μm; 4 The particle size of C ceramic particles is 45 to 300 μm.

[0074] In some embodiments, the drill rod 1 comprises:

[0075] Drill pipe body 11;

[0076] Drill pipe joints, which are respectively located at both ends of the drill pipe body 11, and the drill pipe joints and the drill pipe body 11 are connected by threads;

[0077] The functional structure layer 2 is spirally embedded in the drill pipe body 11 and the surface of the drill pipe joint.

[0078] Specifically, the drill pipe 1 includes a drill pipe body 11 and a drill pipe joint. The drill pipe body 11 is hollow inside, and the drill pipe joint includes a first joint 13 and a second joint 14; the first joint 13 and the second joint 14 are respectively connected to the two ends of the drill pipe body 11, specifically, the first joint 13 and the second joint 14 are respectively threadedly connected to the two ends of the drill pipe body 11, for example, connected to the drill pipe body 11 through a T-type thread; the first joint 13, the second joint 14 and the drill pipe body 11 are all provided with a functional structure layer 2; a first groove is spirally provided on the tube wall 12 of the drill pipe body 11, and the functional structure layer 2 is embedded in the first groove 2; correspondingly, a second groove is spirally opened on the outer circumference of the first joint 13 and the second joint 14, and the functional structure layer 2 is embedded in the second groove.

[0079] In some embodiments, the end surface of the functional structure layer flush with the surface of the drill pipe is further provided with a capping layer 3.

[0080] In some embodiments, the drill pipe body 11 is made of Al-Mg-Sc alloy.

[0081] In some embodiments, the material of the substrate is an Al-Mg alloy.

[0082] In some embodiments, the material of the cap layer is Al-Mg alloy.

[0083] In some embodiments, the material of the drill rod joint is Al-Zn alloy.

[0084] In some embodiments, the thickness of the functional structural layer is 45-50% of the wall thickness of the drill pipe body.

[0085] Based on the same inventive concept, the present invention also provides a process for preparing the above-mentioned aluminum alloy drill rod, comprising the following steps:

[0086] S1. Prepare a drill pipe body;

[0087] S2. Processing a first spirally arranged groove on the wall surface of the drill pipe body, wherein the first groove is adapted to the functional structure layer;

[0088] S3, preparing drill pipe joints;

[0089] S4, processing a second spirally arranged groove on the surface of the drill pipe joint, wherein the second groove is adapted to the functional structure layer;

[0090] S5. Determine an additive manufacturing deposition path according to the structure of the functional structural layer;

[0091] S6, TiC ceramic particles, B 4 C ceramic particles are placed in two powder feeders with independent powder feeding channels, and the two powder feeding channels are connected to the wire-powder synchronous deposition composite welding gun head;

[0092] S7. Install the alloy welding wire corresponding to the substrate on the wire feeder;

[0093] S8. Perform arc additive deposition and control TiC ceramic particles, B according to the additive manufacturing deposition path 4 The powder feeding rate of C ceramic particles is set, and the functional structure layer is printed in the first groove and the second groove. The drill rod joint and the drill rod body are assembled to obtain the aluminum alloy drill rod.

[0094] In some embodiments, the process parameters controlled during arc additive deposition are: deposition current of 90-110A, fuse speed of 5.0-6.0m / min, arc swing amplitude of 4-10mm, arc swing frequency of 2-5Hz, capture rate of TiC ceramic particles by molten pool of 60-70%, and capture rate of B by molten pool of 60-70%. 4 The capture rate of C ceramic particles is 30-40%.

[0095] In some embodiments, the drill pipe body is prepared by an extrusion molding process; the drill pipe joint is prepared by an extrusion molding process; during arc additive deposition, the width of a single deposition layer is 5 to 20 mm, and the thickness of each layer is 0.5 to 2 mm.

[0096] The preparation process of the aluminum alloy drill rod of the present invention is innovative in that it breaks the traditional overall surface reinforcement method of the aluminum-based drill rod and locally strengthens the drill rod surface by using a silk-powder synchronous deposition method, so that the functional structure is metallurgically bonded to the aluminum-based drill rod and is not easy to fall off, while reducing the abuse of the reinforcement material; the aluminum alloy drill rod with dual-phase ceramic particle gradient reinforcement prepared by the present invention can be repaired after the friction surface and functional structure are worn by the silk-powder synchronous deposition arc additive manufacturing process, which can greatly extend the service life of the drill rod and further reduce the product cost.

[0097] The aluminum alloy drill rod and its preparation process of the present application are further described below with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0098] In the following examples, the average particle size of the TiC ceramic particles is 40 μm; 4 The average particle size of C ceramic particles is 100 μm; Example 1

[0099] The present application embodiment provides an aluminum alloy drill rod, comprising:

[0100] Drill pipe body;

[0101] The drill pipe joint is divided into two parts, male and female (i.e. the first joint and the second joint mentioned above), which are located at both ends of the drill pipe body, and the drill pipe joint and the drill pipe body are connected by threads;

[0102] The functional structural layers are respectively spirally embedded in the pipe wall of the drill pipe body and the surface of the drill pipe joint;

[0103] The outer diameter of the drill pipe body is 155mm, the wall thickness of the drill pipe body is 15mm, and the pitch of the functional structural layer is 120mm, which is distributed on the outer surface of the middle section of the pipe wall 80mm away from both ends of the drill pipe body;

[0104] The functional structural layer on the pipe wall of the drill pipe body specifically includes: from the end face embedded in the pipe wall of the drill pipe body to the surface direction of the pipe wall of the drill pipe body, the functional structural layer includes the first layer, the second layer, the third layer, the fourth layer, the fifth layer, the sixth layer, the seventh layer, and the eighth layer stacked in sequence; wherein the thickness of each layer is 1 mm;

[0105] Layers 1 to 5 are the multiple first sub-functional layers mentioned above (including Al5356 alloy matrix and TiC ceramic particles), and layers 6 to 8 are the multiple second sub-functional layers mentioned above (including Al5356 alloy matrix, TiC ceramic particles and B 4C ceramic particles);

[0106] The first layer is Al5356 alloy (the volume fraction of TiC ceramic particles is 0%);

[0107] The second layer includes Al5356 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the second layer is 5%;

[0108] The third layer includes Al5356 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the third layer is 10%;

[0109] The fourth layer includes Al5356 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the fourth layer is 15%;

[0110] The fifth layer includes Al5356 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the fifth layer is 20%;

[0111] The sixth layer includes Al5356 alloy, TiC ceramic particles, B 4 C ceramic particles, the volume fraction of TiC ceramic particles in the 6th layer is 15%, B 4 The volume fraction of C ceramic particles is 4%;

[0112] The seventh layer includes Al5356 alloy, TiC ceramic particles, B 4 C ceramic particles, the volume fraction of TiC ceramic particles in the 7th layer is 10%, B 4 The volume fraction of C ceramic particles is 7%;

[0113] The eighth layer includes Al5356 alloy, TiC ceramic particles, B 4 C ceramic particles, the volume fraction of TiC ceramic particles in the 8th layer is 5%, B 4 The volume fraction of C ceramic particles is 10%;

[0114] The end face of the functional structure layer is flush with the surface of the drill pipe body wall, and a cap layer is also provided on the surface of the functional structure layer. The thickness of the cap layer (Al5356 alloy) is about 1.0 mm.

[0115] Al5356 alloy, its composition (mass fraction) is: Mg 5.0%, Si 0.25%, Fe 0.4%, Cu 0.1%, Zn0.1%, Mn 0.12%, Cr 0.13%, Ti 0.13%, and Al balance.

[0116] Similarly, the functional structural layer on the surface of the drill pipe joint has the same components and composition as the functional structural layer on the wall of the drill pipe body, that is, the functional structural layer on the surface of the drill pipe joint specifically includes: from the end face embedded in the drill pipe joint to the surface direction of the drill pipe joint, the functional structural layer includes the first to eighth layers stacked in sequence, and the thickness composition of each layer is the same as that of the functional structural layer on the wall of the drill pipe body. The functional structural layer on the surface of the drill pipe joint is also provided with a cap layer (Al5356 alloy), and the thickness of the cap layer is about 1.0 mm; the material of the drill pipe body is AlMg5.5ScZr, and its composition (mass fraction) is: Si0.20%, Mg 4.9-6.1%, Fe 0.30%, Cu 0.10%, Zn 0.30-0.90%, Mn 0.20-0.50%, Ti0.12%, Sc 0.50-0.70%, Zr 0.05-0.30%, Al remainder;

[0117] The material of the drill pipe joint is Al7075, and its composition (mass fraction) is: Si 0.40%, Mg 2.1-2.9%, Fe0.40%, Cu 1.2-2%, Zn 5.1-6.1%, Mn 0.20%, Ti 0.2%, Cr 0.18-0.28%, and Al balance.

[0118] The preparation process of the aluminum alloy drill rod in the above-mentioned embodiment 1 comprises the following steps:

[0119] S1. Preparation of a drill pipe body: using an extrusion molding method, preheating an AlMg5.5ScZr rod and placing it into an extrusion molding die to obtain a drill pipe body;

[0120] S2, preparation of drill pipe joint: using extrusion molding method, preheating Al7075 rod and putting it into extrusion molding die to obtain drill pipe joint;

[0121] S3. Annealing heat treatment of the drill pipe body: annealing at 300℃ for 2 hours; T6 heat treatment of the drill pipe joint: insulation at 500℃ for 3 hours, aging parking time ≥ 80h; then quality inspection, straightening and diameter quality inspection;

[0122] S4, machining the drill pipe body and the drill pipe joint; machining the first and second spirally arranged grooves on the surfaces of the drill pipe body and the drill pipe joint respectively by milling;

[0123] S5. According to the structure of the functional structural layer, the digital model of the aluminum alloy drill pipe is imported into the additive manufacturing system, the functional structural layer is sliced ​​and the additive manufacturing deposition path is automatically generated;

[0124] S6, arc additive manufacturing of the functional structural layer of the drill pipe; fix the machined drill pipe body and drill pipe joint on the positioner respectively, and clean and dry the surface of the drill pipe; dry TiC ceramic particles, B 4 C ceramic particle powders were loaded into independent powder feeders respectively, and Al5356 alloy welding wire with a diameter of 1.2 mm was installed on the automatic wire feeder to ensure smooth wire and powder feeding; the control program was started, and the wire-powder composite welding gun was controlled by a CNC machine tool or a robot to perform arc additive deposition; the additive deposition current was 95A, the fuse speed was about 5.0 m / min, the arc swing amplitude was 6 mm, the arc swing frequency was 3 Hz, and the shielding gas and powder feeding gas were both 99.999% high-purity Ar gas; the capture rate of TiC powder in the molten pool was 70%, and that of B 4 The capture rate of C powder is 40%. The powder feeding rate of ceramic powder can be determined according to the designed content of ceramic particles in the corresponding deposition layer. According to the requirements of the layered design of the functional structure layer, the program chooses to open or close the powder feeding channel of the powder feeder storing the corresponding ceramic powder, and executes the corresponding powder feeding rate: when depositing the second layer, the powder feeding rate of TiC ceramic particles is controlled to be 2.10g / min; when depositing the third layer, the powder feeding rate of TiC ceramic particles is controlled to be 4.42g / min; when depositing the fourth layer, the powder feeding rate of TiC ceramic particles is controlled to be 6.99g / min; when depositing the fifth layer, the powder feeding rate of TiC ceramic particles is controlled to be 9.95g / min; when depositing the sixth layer, the powder feeding rate of TiC ceramic particles is controlled to be 7.37g / min, B 4 The powder feeding rate of C ceramic particles is 1.75 g / min; when depositing the 7th layer, the powder feeding rate of TiC ceramic particles is controlled to be 4.80 g / min, B 4 The powder feeding rate of C ceramic particles is 2.99 g / min. When depositing the 8th layer, the powder feeding rate of TiC ceramic particles is controlled to be 2.34 g / min. 4 The powder feeding rate of C ceramic particles is 4.17g / min; the protective gas flow rate is 15L / min, the powder feeding gas flow rate is 5L / min, and B 4 The powder feeding gas flow rate of C is 3L / min; finally, a functional structural layer is prepared; at the same time, an Al5356 capping layer of about 1.0mm is deposited on the functional structural layer;

[0125] S7, finishing of the drill pipe body and drill pipe joints; processing external threads at both ends of the drill pipe body; processing internal threads at both ends of the inner diameter wall of the first joint; processing internal threads on the inner diameter wall of the end of the second joint connected to the drill pipe body, and processing external threads on the outer diameter wall of the trapezoidal end connected to the next section of drill pipe;

[0126] S8. Hot assembly of aluminum alloy drill pipe: Use a hot assembly device to first heat the drill pipe joint to 200-300℃ to expand it, then screw it onto the aluminum alloy drill pipe body in a hot state, and then cool it. After cooling, the threaded connection can obtain a certain preload force to meet the needs of the aluminum alloy drill pipe to transmit torque and bear load.

[0127] Example 2

[0128] The present application embodiment provides an aluminum alloy drill rod, comprising:

[0129] Drill pipe body;

[0130] The drill pipe joint is divided into two parts, male and female (i.e. the first joint and the second joint mentioned above), which are located at both ends of the drill pipe body, and the drill pipe joint and the drill pipe body are connected by threads;

[0131] The functional structural layers are respectively spirally embedded in the pipe wall of the drill pipe body and the surface of the drill pipe joint;

[0132] The outer diameter of the drill pipe body is 114mm, the wall thickness of the drill pipe body is 20mm, and the pitch of the functional structural layer is 120mm, which is distributed on the outer surface of the middle section of the pipe wall 70mm away from both ends of the drill pipe body;

[0133] The functional structural layer on the pipe wall of the drill pipe body specifically includes: from the end face embedded in the pipe wall of the drill pipe body to the surface direction of the pipe wall of the drill pipe body, the functional structural layer includes the first layer, the second layer, the third layer, the fourth layer, the fifth layer, the sixth layer, the seventh layer, the eighth layer, the ninth layer, and the tenth layer stacked in sequence; wherein the thickness of each layer is 1 mm;

[0134] Layers 1 to 6 are the multiple first sub-functional layers mentioned above (including Al5083 alloy matrix and TiC ceramic particles), and layers 7 to 10 are the multiple second sub-functional layers mentioned above (including Al5083 alloy matrix, TiC ceramic particles and B 4 C ceramic particles);

[0135] The first layer is Al5083 alloy (the volume fraction of TiC ceramic particles is 0%);

[0136] The second layer includes Al5083 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the second layer is 5%;

[0137] The third layer includes Al5083 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the third layer is 10%;

[0138] The fourth layer includes Al5083 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the fourth layer is 15%;

[0139] The fifth layer includes Al5083 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the fifth layer is 20%;

[0140] The sixth layer includes Al5083 alloy and TiC ceramic particles, and the volume fraction of TiC ceramic particles in the sixth layer is 23%;

[0141] The seventh layer includes Al5083 alloy, TiC ceramic particles, B 4 C ceramic particles, the volume fraction of TiC ceramic particles in the 7th layer is 18%, B 4 The volume fraction of C ceramic particles is 3%;

[0142] The eighth layer includes Al5083 alloy, TiC ceramic particles, B 4 C ceramic particles, the volume fraction of TiC ceramic particles in the 8th layer is 12%, B 4 The volume fraction of C ceramic particles is 7%;

[0143] The ninth layer includes Al5083 alloy, TiC ceramic particles, B 4 C ceramic particles, the volume fraction of TiC ceramic particles in the 9th layer is 8%, B 4 The volume fraction of C ceramic particles is 9%;

[0144] The 10th layer includes Al5083 alloy, TiC ceramic particles, B 4 C ceramic particles, the volume fraction of TiC ceramic particles in the 10th layer is 3%, B 4 The volume fraction of C ceramic particles is 12%;

[0145] The end face of the functional structure layer is flush with the surface of the drill pipe body wall, and a cap layer is also provided on the surface of the functional structure layer. The thickness of the cap layer (Al5083 alloy) is about 1.0 mm.

[0146] Al5083 alloy, whose composition (mass fraction) is: Mg 4.5-5.2%, Mn 0.5-1.0%, Cr 0.15-0.25%, Si 0.4%, Fe 0.4%, Cu 0.1%, Zn 0.25%, Ti 0.15%, Al balance;

[0147] Similarly, the functional structural layer on the surface of the drill pipe joint has the same components and composition as the functional structural layer on the wall of the drill pipe body, that is, the functional structural layer on the surface of the drill pipe joint specifically includes: from the end face embedded in the drill pipe joint to the surface direction of the drill pipe joint, the functional structural layer includes the first to tenth layers stacked in sequence, and the thickness composition of each layer is the same as that of the functional structural layer on the wall of the drill pipe body. The functional structural layer on the surface of the drill pipe joint is also provided with a cap layer (Al5083 alloy), and the thickness of the cap layer is about 1.0 mm;

[0148] The materials of the drill pipe body and the drill pipe joint are the same as those in Example 1.

[0149] The preparation process of the aluminum alloy drill rod in the above-mentioned embodiment 2, the main steps S1-S5, S7-S8 are the same as those in the embodiment 1, and the difference is that: S6, arc additive manufacturing of the functional structure layer of the drill rod; fixing the machined drill rod body and the drill rod joint on the positioner respectively, and cleaning and drying the surface of the drill rod; drying the TiC ceramic particles, B 4 C ceramic particle powders were loaded into independent powder feeders respectively, and Al5083 alloy welding wire with a diameter of 1.2 mm was installed on the automatic wire feeder to ensure smooth wire and powder feeding; the control program was started, and the wire-powder composite welding gun was controlled by a CNC machine tool or a robot to perform arc additive deposition; the additive deposition current was 105A, the fuse speed was about 5.2m / min, the arc swing amplitude was 8mm, the arc swing frequency was 2Hz, and the shielding gas and powder feeding gas were both 99.999% high-purity Ar gas; the capture rate of TiC powder in the molten pool was 70%, and that of B 4 The capture rate of C powder is 40%. The powder feeding rate of ceramic powder can be determined according to the designed content of ceramic particles in the corresponding deposition layer. According to the requirements of the layered design of the functional structure layer, the program chooses to open or close the powder feeding channel of the powder feeder storing the corresponding ceramic powder, and executes the corresponding powder feeding rate: when depositing the second layer, the powder feeding rate of TiC ceramic particles is controlled to be 2.18g / min; when depositing the third layer, the powder feeding rate of TiC ceramic particles is controlled to be 4.60g / min; when depositing the fourth layer, the powder feeding rate of TiC ceramic particles is controlled to be 7.31g / min; when depositing the fifth layer, the powder feeding rate of TiC ceramic particles is controlled to be 10.35g / min; when depositing the sixth layer, the powder feeding rate of TiC ceramic particles is controlled to be 12.37g / min, B 4 The powder feeding rate of C ceramic particles is 1.75 g / min. When depositing the 7th layer, the powder feeding rate of TiC ceramic particles is controlled to be 9.43 g / min. 4 The powder feeding rate of C ceramic particles is 1.40 g / min. When depositing the 8th layer, the powder feeding rate of TiC ceramic particles is controlled to be 6.13 g / min. 4 The powder feeding rate of C ceramic particles is 3.19 g / min. When depositing the 9th layer, the powder feeding rate of TiC ceramic particles is controlled to be 3.99 g / min. 4 The powder feeding rate of C ceramic particles is 3.40 g / min. When depositing the 10th layer, the powder feeding rate of TiC ceramic particles is controlled to be 1.46 g / min. 4 The powder feeding rate of C ceramic particles is 5.21g / min; the protective gas flow rate is 15L / min, the powder feeding gas flow rate is 5L / min, and B 4C powder feeding gas flow rate is 3L / min; finally a functional structural layer is prepared; at the same time, an Al5083 capping layer of about 1.0mm is deposited on the functional structural layer.

[0150] Example 3

[0151] The aluminum alloy drill rod provided in this embodiment is the same as that in Embodiment 1, except that the base material of the functional structure layer is Al5083 alloy, the material of the cover layer is Al5083 alloy, and the rest is the same as that in Embodiment 1;

[0152] The preparation process of the aluminum alloy drill pipe provided in Example 3 is the same as that in Example 1, except that step S6 is: fixing the machined drill pipe body and drill pipe joint on a positioner, cleaning and drying the surface of the drill pipe; drying the TiC ceramic particles, B 4 C ceramic particle powders are respectively loaded into independent powder feeders, and Al5083 alloy welding wire with a diameter of 1.2 mm is installed on an automatic wire feeder to ensure smooth wire and powder feeding; the rest of the processes are the same as in Example 1.

[0153] Example 4

[0154] The aluminum alloy drill rod provided in this embodiment is the same as that in Embodiment 2, except that the base material of the functional structure layer is Al5356 alloy, the material of the cover layer is Al5356 alloy, and the rest is the same as that in Embodiment 2;

[0155] The preparation process of the aluminum alloy drill pipe provided in Example 4 is the same as that in Example 2, except that step S6 is: fixing the machined drill pipe body and drill pipe joint on a positioner, cleaning and drying the surface of the drill pipe; drying the TiC ceramic particles, B 4 C ceramic particle powders are respectively loaded into independent powder feeders, and Al5356 alloy welding wire with a diameter of 1.2 mm is installed on an automatic wire feeder to ensure smooth wire and powder feeding; the rest of the processes are the same as in Example 2.

[0156] Comparative Example 1

[0157] This comparative example provides a conventional aluminum alloy drill pipe without a functional structure, and its dimensions are: the outer diameter of the drill pipe body is 114 mm, and the wall thickness of the drill pipe body is 20 mm; the drill pipe body is made of 7E04-T6, and its composition (mass fraction) is: Cu 1.4-2.0%, Mn 0.2-0.6%, Cr 0.10-0.25%, Mg 1.8-2.8%, Fe 0.05-0.25%, Zn 5.0-6.5%, Si<0.1%, Ti<0.05%, Al remainder; the drill pipe joint is made of wear-resistant steel.

[0158] Performance test (only for the aluminum-based drill pipe body. In Examples 1 to 4, the tested drill pipe body contains a functional structure layer (excluding the drill pipe joint), and in Comparative Example 1, the tested drill pipe body does not have a functional structure layer, excluding the drill pipe joint).

[0159] Test the various performances of the drill pipe bodies in Examples 1 to 4 and Comparative Example 1, and the results are shown in Table 1.

[0160] Table 1 Performance test data of drill pipe bodies in examples and comparative examples

[0161]

[0162] It can be seen from the performance test data in Table 1 that the room-temperature mechanical properties of the aluminum alloy drill pipe of the present invention are superior to those of Comparative Example 1. Especially in a high-temperature environment of 250 °C, the tensile strength of the drill pipe bodies in Examples 1 to 4 is 1.5 to 1.6 times that of the drill pipe body in Comparative Example 1, and the elongation rate is about 1.3 times that of the drill pipe body in Comparative Example 1; in the room-temperature dry friction and wear test with granite, the wear rate of the drill pipe bodies in Examples 1 to 4 is only 1 / 30 of that of the drill pipe body in Comparative Example 1, showing excellent wear resistance; the damping coefficient of the drill pipe bodies in Examples 1 to 4 is 3 to 4 times that of the drill pipe body in Comparative Example 1, indicating that the aluminum alloy drill pipe of the present invention has better shock absorption performance than conventional aluminum alloy drill pipes; in addition, the room-temperature thermal conductivity of the drill pipe bodies in Examples 1 to 4 is about 2 times that of the drill pipe body in Comparative Example 1, indicating that the aluminum alloy drill pipe of the present invention has good heat dissipation performance.

[0163] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An aluminum alloy drill rod, characterized in that: include: Drill pipe; A functional structural layer, spirally embedded on the surface of the drill rod; Wherein, one end surface of the functional structure layer is embedded in the drill rod, and the other end surface is flush with the surface of the drill rod; The functional structural layer includes a matrix, TiC ceramic particles, and B4C ceramic particles; Wherein, the volume fraction of the TiC ceramic particles increases with the increase of the thickness of the functional structure layer from the end surface embedded in the drill rod to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer; When the thickness of the functional structure layer exceeds 1 / 2 to 5 / 8 of the thickness of the functional structure layer, the volume fraction of the TiC ceramic particles decreases as the thickness of the functional structure layer increases, and the volume fraction of the B4C ceramic particles increases as the thickness of the functional structure layer increases.

2. The aluminum alloy drill rod according to claim 1, characterized in that: The functional structure layer is from the end surface embedded in the drill pipe to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer, the volume fraction of the TiC ceramic particles increases from 0% to 20 to 30% as the thickness of the functional structure layer increases, and the volume fraction of the B4C ceramic particles is 0%; When the thickness of the functional structure layer exceeds 1 / 2 to 5 / 8 of the thickness of the functional structure layer, the volume fraction of the TiC ceramic particles decreases from 20 to 30% to 3 to 5% as the thickness of the functional structure layer increases, and the volume fraction of the B4C ceramic particles increases from 0% to 10 to 20% as the thickness of the functional structure layer increases.

3. The aluminum alloy drill pipe according to claim 2, characterized in that: The functional structure layer extends from the end face embedded in the drill rod to the position of 1 / 2 to 5 / 8 of the thickness of the functional structure layer, and the functional structure layer includes a plurality of first sub-functional structure layers stacked in layers, and the volume fraction of B4C ceramic particles in each first sub-functional structure layer is 0%; wherein the volume fraction of TiC ceramic particles in the first sub-functional structure layer farthest from the surface of the drill rod is 0%, and the volume fraction difference of TiC ceramic particles in any two adjacent first sub-functional structure layers is 3 to 5%; The thickness of the functional structural layer is from 1 / 2 to 5 / 8 of the thickness of the functional structural layer to the end face flush with the surface of the drill pipe, and the functional structural layer includes a plurality of second sub-functional structural layers stacked in layers; wherein the volume fraction of TiC ceramic particles in the second sub-functional structural layer farthest from the surface of the drill pipe is 15 to 25%, the volume fraction of B4C ceramic particles is 3 to 4%, the volume fraction difference of TiC ceramic particles in any two adjacent second sub-functional structural layers is 4 to 6%, and the volume fraction difference of B4C ceramic particles is 2 to 4%.

4. The aluminum alloy drill rod according to claim 1, characterized in that: The particle size of the TiC ceramic particles is 25 to 60 μm; the particle size of the B4C ceramic particles is 45 to 300 μm.

5. The aluminum alloy drill rod according to any one of claims 1 to 4, characterized in that: The drill pipe comprises: Drill pipe body; Drill pipe joints, which are respectively located at two ends of the drill pipe body, and the drill pipe joints are connected to the drill pipe body by threads; The functional structural layers are respectively spirally embedded on the surfaces of the drill pipe body and the drill pipe joint.

6. The aluminum alloy drill rod according to claim 5, characterized in that: The end surface of the functional structure layer flush with the surface of the drill rod is also provided with a capping layer with a thickness of 0.5 to 2.0 mm.

7. The aluminum alloy drill rod according to claim 6, characterized in that: The material of the drill pipe body is Al-Mg-Sc-Zr alloy; The material of the substrate is Al-Mg alloy; The material of the capping layer is Al-Mg alloy; The material of the drill pipe joint is Al-Zn alloy; The thickness of the functional structural layer is 45-50% of the wall thickness of the drill pipe body.

8. A process for preparing an aluminum alloy drill rod according to any one of claims 1 to 7, characterized in that: The following steps are involved: preparing a drill pipe body; A first groove arranged in a spiral shape is processed on the surface of the drill pipe body, wherein the first groove is adapted to the functional structure layer; Prepare drill pipe joints; A second groove arranged in a spiral shape is processed on the surface of the drill rod joint, wherein the second groove is adapted to the functional structure layer; Determine the additive manufacturing deposition path based on the structure of the functional structural layer; TiC ceramic particles and B4C ceramic particles are placed in two powder feeders with independent powder feeding channels respectively, and the two powder feeding channels are connected to a wire-powder synchronous deposition composite welding gun head; Install the alloy welding wire corresponding to the substrate on the wire feeder; According to the additive manufacturing deposition path, arc additive deposition is performed and the powder feeding rate of TiC ceramic particles and B4C ceramic particles is controlled to print the functional structure layer in the first groove and the second groove.

9. The process for preparing the aluminum alloy drill pipe according to claim 8, characterized in that: The process parameters controlled during arc additive deposition are: deposition current of 90-110A, fuse speed of 5.0-6.0m / min, arc swing amplitude of 4-10mm, arc swing frequency of 2-5Hz, capture rate of TiC ceramic particles by the molten pool of 60-70%, and capture rate of B4C ceramic particles by the molten pool of 30-40%.

10. The process for preparing the aluminum alloy drill pipe according to claim 8, characterized in that: The drill pipe body is prepared by an extrusion molding process; the drill pipe joint is prepared by an extrusion molding process; during arc additive deposition, the width of a single deposition layer is 5 to 20 mm, and the thickness of each layer is 0.5 to 2 mm.

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