A double-hole copper tube and its production process

Abstract

The present invention relates to the field of copper tube processing, and discloses a production process of a double-hole copper tube, comprising the following steps: step 1, welding a copper strip into a copper tube blank with a relatively large diameter by a welding machine; step 2, stretching the copper tube blank with a relatively large diameter by a coiling and pulling car to form a copper tube blank with a relatively small diameter; step 3, cutting the copper tube blank with a relatively small diameter into several sections, and then inserting a copper wire from one end of the copper tube blank and leading it out from the other end to form a copper tube blank set; step 4, placing the copper tube blank set under protective gas for annealing treatment to form a copper tube blank set annealing material; step 5, stretching the copper tube blank set annealing material on a coiling and pulling car again until the copper wire is clamped on the inner wall of the copper tube blank and cannot move, thereby obtaining the desired double-hole copper tube. The process of the double-hole copper tube of the present invention is one-step and integrally formed, which overcomes the complex process that the existing copper tube needs to be stretched by a single strip and then welded.

Description

Technical Field

[0001] The invention relates to the field of copper tube processing, and in particular to a double-hole copper tube and a production process thereof. Background Art

[0002] Humans have been using copper and copper alloys for a long time. They have accompanied the Chinese nation through nearly 5,000 years of history. Copper and copper alloys are still very popular non-ferrous metals. Due to the unique qualities and characteristics of copper and copper alloys, they have been gradually understood by people with the development of science and technology. Copper and copper alloys are widely used in many fields such as cables, wires, air conditioning and refrigeration industries, plumbing and construction industries, etc.

[0003] Because copper has excellent ductility, electrical conductivity, thermal conductivity, and is easy to process, copper will not undergo much modification within the range of ±196℃. There are many grades of copper and copper alloys. The deformed copper alloys produced in my country are roughly divided into four categories: brass, copper, bronze, and nickel silver. Copper pipes have good electrical and thermal conductivity characteristics. They are the main materials for conductive accessories and heat dissipation accessories of electronic products, and have become the first choice for modern contractors to install tap water pipes, heating, and cooling pipes in all residential commercial houses. Copper pipes have strong corrosion resistance, are not easy to oxidize, and are not easy to react chemically with some liquid substances, and are easy to bend and shape.

[0004] Under normal conditions, copper tubes are generally used in heat exchange equipment, and can also be used in low-temperature pipelines in oxygen production equipment. Some relatively thin copper tubes can be used to transport some pressurized liquids, and can also be used as pressure measuring tubes in instruments. In addition, copper tubes are the core material of electrode tubes. Electrode tubes (also known as electrode copper tubes, copper tubes for punching machines) are special electrodes for processing small holes in spark machines. They process various deep small holes and blind holes. The products include red copper tubes, brass tubes, and bronze tubes. However, in the preparation of electrode tubes, single-hole tubes can no longer fully meet the application, and the demand for double-hole tubes is also increasing. However, the current technology on the market is relatively complicated for the processing of double-hole copper tubes, and based on the limitations of copper tube materials, it is impossible to truly achieve double-hole copper tubes suitable for electrode tubes. Summary of the invention

[0005] In view of the problems existing in the prior art, the object of the present invention is to provide a double-hole copper tube and a production process thereof.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] In a first aspect, the present invention provides a production process for a double-hole copper tube, comprising the following steps:

[0008] Step 1, welding the copper strip into a copper tube blank with a relatively thick diameter by a welding machine;

[0009] Step 2, the copper tube blank with a larger diameter is stretched by a coil puller to form a copper tube blank with a smaller diameter;

[0010] Step 3, cutting the copper tube blank with a smaller diameter into several sections, and then inserting the copper wire into one end of the copper tube blank and leading it out from the other end to form a copper tube blank set;

[0011] Step 4, placing the copper tube rough blank set under protective gas for annealing treatment to form an annealed material for the copper tube rough blank set;

[0012] Step 5, the annealed copper tube blank set is stretched again on the coil-pulling vehicle until the copper wire is clamped on the inner wall of the copper tube blank and cannot move, thereby obtaining the desired double-hole copper tube.

[0013] Preferably, the outer diameter of the copper tube blank with a larger diameter is 4-6 mm, and the tube wall thickness is 0.1-0.5 mm.

[0014] Preferably, the outer diameter of the copper tube blank with a relatively small diameter is 2-4 mm, the coefficient of each stretching is 0.5-0.7 mm, and the stretching speed is 25-30 m / min.

[0015] Preferably, the annealing temperature is 500-600° C., the annealing time is 4-6 hours, and the protective gas includes hydrogen and nitrogen in a volume ratio of 1:10.

[0016] Preferably, the diameter of the copper wire is 1.5-1.8 mm, and the length of the copper wire is longer than the length of the copper tube after stretching.

[0017] In a second aspect, the present invention provides a material for the above-mentioned double-hole copper tube, including a copper strip material and a copper wire material, wherein the copper strip material and the copper wire material have the same composition and preparation method, and are both prepared by using powder metallurgy.

[0018] Preferably, the method for preparing the material of the double-hole copper tube includes:

[0019] (1) Ball milling process: Copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres are mixed uniformly, and ball milled in a planetary ball mill with a ball-to-material ratio of 4-6:1, a ball milling time of 8-12 hours, and a ball milling speed of 200-300 r / min. After the ball milling is completed, a ball milled mixture is obtained;

[0020] (2) Molding process: The ball milled mixture is placed in a metal powder cold pressing molding machine for cold pressing treatment at a pressure of 80-100 MPa for a cold pressing time of 2-4 h to obtain a molded blank;

[0021] (3) Sintering process: Place the formed blank in a high-temperature electric furnace, evacuate the vacuum, heat it to 500-600°C at a rate of 5°C / min, keep it warm for 1 hour, continue to heat it to 900-1000°C at a rate of 5°C / min, keep it warm for 2 hours, and naturally cool it to room temperature; then introduce inert gas as protective gas, heat it to 500-600°C at a rate of 10°C / min, keep it warm for 2 hours, heat it to 900-1000°C at a rate of 10°C / min, keep it warm for 3-5 hours, first cool it to 300°C at a rate of 5°C / min, and then naturally cool it to room temperature to obtain the material of the double-hole copper tube.

[0022] Preferably, during the ball milling process, the weight ratio of copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres is 88.4-91.2:5.4-6.6:1.7-2.5:1.4-2.8; the purity of copper powder, zinc powder and iron powder is higher than 99.99%, and the particle size is 10±2μm.

[0023] Preferably, the preparation process of yttrium carbide-yttrium silicide composite microspheres comprises:

[0024] S1, dissolving yttrium salt in deionized water, stirring evenly to form a yttrium salt solution; dissolving sodium deoxycholate in deionized water, stirring evenly to form a sodium deoxycholate solution;

[0025] S2, adding the sodium deoxycholate solution dropwise into the yttrium salt solution, generating a large amount of flocs, stirring thoroughly, centrifuging the flocs, washing them with pure water at least three times, drying them in a vacuum oven, and crushing them to obtain a yttrium deoxycholate compound;

[0026] S3, mixing the yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water, and stirring them sufficiently to form a uniform first mixed slurry;

[0027] S4, pouring the first mixed slurry into an AM100 planetary ball mill, and obtaining a second mixed slurry after the ball milling is completed;

[0028] S5, pouring the second mixed slurry into an experimental spray dryer, and spray drying to obtain a mixed microsphere powder;

[0029] S6, spreading the mixed microsphere powder on the surface of the crucible, placing the crucible in a high-temperature electric furnace, heating and sintering under an inert gas atmosphere, and then cooling to room temperature to obtain yttrium carbide-yttrium silicide composite microspheres.

[0030] Preferably, in S1, the yttrium salt is yttrium nitrate, and the mass ratio of the yttrium salt to deionized water in the yttrium salt solution is 5-10:100.

[0031] Preferably, in S1, the mass ratio of sodium deoxycholate to deionized water in the sodium deoxycholate solution is 5-10:100.

[0032] Preferably, in S2, the mass ratio of the sodium deoxycholate solution to the yttrium salt solution is 1:5.2-6.4.

[0033] Preferably, in S3, the mass ratio of yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water is 1:0.3-0.5:0.05-0.1:10; and the particle size of nano-yttrium silicide is 200-400nm.

[0034] Preferably, in S4, the model of the planetary ball mill is AM100, the ball-to-material ratio is 8-10:1, the ball milling time is 10-15h, and the ball milling speed is 200-300r / min.

[0035] Preferably, in S5, the temperature of the air inlet of the dryer is adjusted to 170-190°C, the air outlet temperature is controlled to 70-80°C, and the liquid inlet speed is 10-20mL / min.

[0036] Preferably, in S6, the temperature raising sintering is firstly to raise the temperature to 400-450°C at a rate of 5°C / min, keep it at that temperature for 1-2h, then continue to raise the temperature to 1250-1350°C at a rate of 10°C / min, keep it at that temperature for 2-4h; cooling to room temperature is firstly to lower the temperature to 300°C at a rate of 5°C / min, and then naturally cool to room temperature.

[0037] Preferably, the diameter of the yttrium carbide-yttrium silicide composite microspheres is 40-50 μm.

[0038] The beneficial effects of the present invention are:

[0039] 1. The present invention improves the existing copper tube to adapt to the application on the double-hole electrode tube. The process of preparing the double-hole copper tube is also very simple and practical. The copper wire and the copper tube cooperate with each other to achieve the copper wire finally clamped inside the copper tube, and the copper tube is divided into a double-hole structure. The process of the double-hole copper tube is one-step and integrally formed, which overcomes the complex process of the existing copper tube that needs to be stretched and then welded.

[0040] 2. During the stretching and thinning process of the copper tube, the dimensional changes are reflected in the axial length and wall thickness. The copper tube is subjected to axial and circumferential pressure under the stretching action, and as the deformation gradually proceeds, its axial length and the wall thickness of the tube in the deformation zone continue to change. The copper wire inside the copper tube plays a role in strengthening and buffering, making the changes in the axial length and wall thickness of the double-hole copper tube more uniform during the stretching process, and it is not easy to break.

[0041] 3. During the stretching process, the copper tube sometimes needs to be bent to adapt to the product. However, in the process of bending the traditional copper tube, the bent part has to be subjected to local force, which causes local over-stretching, cracking, dark cracks and other problems. This will not only affect the service life of the copper tube, but also lead to safety hazards during use. In order to solve this problem, in addition to the improvement of the above-mentioned process, the present invention also improves the material of the copper tube, and adds zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres in the preparation of the copper tube material. Compared with copper tubes made of general materials, the copper tube prepared by the present invention has higher strength and toughness, and is less likely to crack and dark crack during the bending process. In addition, based on the addition of a small amount of yttrium carbide-yttrium silicide composite microspheres in the copper material, it is found through experimental detection that the corrosion resistance of the copper tube can also be effectively enhanced.

[0042] 4. The yttrium carbide-yttrium silicide composite microspheres in the present invention are rough porous structures. The preparation process is based on the rare earth element yttrium as the basic material, yttrium silicide as the basic core material, and yttrium carbide as the composite coating material. The composite process of the microspheres is to first use sodium deoxycholate to complex with yttrium salt to form an organic chelate of yttrium, then combine the organic chelate of yttrium with nano-scale yttrium silicide ball mill, spray dry to form a microsphere structure, and then sinter at high temperature, the organic matter gradually decomposes, and the organic chelate of yttrium gradually transforms into yttrium carbide, thereby forming a porous composite microsphere structure of yttrium carbide coated with yttrium silicide. In the preparation of copper tube materials, the particle size of the yttrium carbide-yttrium silicide composite microspheres is set to be larger than the particle size of copper powder. The purpose of such treatment is to have a larger contact area and easier adhesion with copper powder during the process of ball milling and mixing with copper powder. Moreover, compared with pure yttrium carbide, the composite microspheres synthesized by the present invention have better performance improvement for copper tube materials. DETAILED DESCRIPTION

[0043] In order to more clearly illustrate the present invention and have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0044] The present invention will be further described below in conjunction with the following examples.

[0045] Example 1

[0046] A production process for a double-hole copper tube comprises the following steps:

[0047] Step 1, welding the copper strip into a copper tube blank with an outer diameter of 5 mm and a tube wall thickness of 0.3 mm by a welding machine;

[0048] Step 2, the copper tube blank is stretched by a coil puller, the stretching coefficient is 0.6 mm each time, the stretching speed is 30 m / min, and the copper tube blank with an outer diameter of 3 mm is formed;

[0049] Step 3, cutting the copper tube blank into several sections, and then inserting a copper wire with a diameter of 1.6 mm from one end of the copper tube blank and leading it out from the other end, wherein the length of the copper wire is longer than the length of the copper tube after stretching, to form a copper tube blank set;

[0050] Step 4, placing the copper tube rough blank set under protective gas (hydrogen and nitrogen volume ratio is 1:10) for annealing, the annealing temperature is 500° C., the annealing time is 5 hours, and the copper tube rough blank set annealing material is formed;

[0051] Step 5, the annealed copper tube blank set is stretched again on the coil-pulling vehicle until the copper wire is clamped on the inner wall of the copper tube blank and cannot move, thereby obtaining the desired double-hole copper tube.

[0052] The materials of the above-mentioned double-hole copper tube include copper strip material and copper wire material, wherein the copper strip material and the copper wire material have the same composition and preparation method, and are both prepared by using powder metallurgy.

[0053] Preferably, the method for preparing the material of the double-hole copper tube includes:

[0054] (1) Ball milling process: Copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres are mixed uniformly, and ball milled in a planetary ball mill with a ball-to-material ratio of 5:1, a ball milling time of 10 h, and a ball milling speed of 200 r / min. After the ball milling, a ball milled mixture is obtained; wherein the weight ratio of copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres is 89.8:6:2.1:2.1; the purity of copper powder, zinc powder and iron powder is higher than 99.99%, and the particle size is all 10±2 μm.

[0055] (2) Molding process: The ball milled mixture is placed in a metal powder cold pressing machine for cold pressing at a pressure of 100 MPa for 3 h to obtain a molded blank;

[0056] (3) Sintering process: Place the formed blank in a high-temperature electric furnace, evacuate the vacuum, heat it to 500°C at a rate of 5°C / min, keep it warm for 1 hour, continue to heat it to 1000°C at a rate of 5°C / min, keep it warm for 2 hours, and naturally cool it to room temperature; then introduce inert gas as protective gas, heat it to 500°C at a rate of 10°C / min, keep it warm for 2 hours, heat it to 1000°C at a rate of 10°C / min, keep it warm for 4 hours, first cool it to 300°C at a rate of 5°C / min, and then naturally cool it to room temperature to obtain the material of the double-hole copper tube.

[0057] Preferably, the preparation process of yttrium carbide-yttrium silicide composite microspheres comprises:

[0058] S1, dissolving yttrium nitrate in deionized water, the mass ratio of yttrium nitrate to deionized water is 8:100, stirring evenly to form an yttrium nitrate solution; dissolving sodium deoxycholate in deionized water, the mass ratio of sodium deoxycholate to deionized water is 8:100, stirring evenly to form a sodium deoxycholate solution;

[0059] S2, adding the sodium deoxycholate solution dropwise into the yttrium nitrate solution, the mass ratio of the sodium deoxycholate solution to the yttrium nitrate solution is 1:5.8, a large amount of floccules are generated, after sufficient stirring, the floccules are centrifuged and washed with pure water for at least three times, dried in a vacuum box, and crushed to obtain a yttrium deoxycholate compound;

[0060] S3, mixing yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water, wherein the mass ratio of yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water is 1:0.4:0.08:10, and the particle size of nano-yttrium silicide is 200-400 nm, and after sufficient stirring, a uniform first mixed slurry is formed;

[0061] S4, pouring the first mixed slurry into an AM100 planetary ball mill, with a ball-to-material ratio of 9:1, a ball milling time of 12 h, and a ball milling speed of 250 r / min. After the ball milling is completed, a second mixed slurry is obtained;

[0062] S5, pouring the second mixed slurry into an experimental spray dryer, adjusting the air inlet temperature to 180°C, the air outlet temperature to 75°C, the liquid inlet speed to 15mL / min, and spray drying to obtain a mixed microsphere powder;

[0063] S6, spread the mixed microsphere powder on the surface of the crucible, place the crucible in a high-temperature electric furnace, and heat and sinter in an inert gas atmosphere. The temperature is first raised to 400°C at a rate of 5°C / min, and after keeping it warm for 1 hour, it is continued to be heated to 1300°C at a rate of 10°C / min, and kept warm for 3 hours. After the temperature is raised and sintered, it is first cooled to 300°C at a rate of 5°C / min, and then naturally cooled to room temperature to obtain yttrium carbide-yttrium silicide composite microspheres with a diameter of 40-50μm.

[0064] Example 2

[0065] A production process for a double-hole copper tube comprises the following steps:

[0066] Step 1, welding the copper strip into a copper tube blank with an outer diameter of 4 mm and a tube wall thickness of 0.1 mm by a welding machine;

[0067] Step 2, the copper tube blank is stretched by a coil puller, the stretching coefficient is 0.5 mm each time, and the stretching speed is 25 m / min, to form a copper tube blank with an outer diameter of 2 mm;

[0068] Step 3, cutting the copper tube blank into several sections, and then inserting a copper wire with a diameter of 1.5 mm from one end of the copper tube blank and leading it out from the other end, wherein the length of the copper wire is longer than the length of the copper tube after stretching, to form a copper tube blank set;

[0069] Step 4, placing the copper tube rough blank set under protective gas (hydrogen and nitrogen volume ratio is 1:10) for annealing, the annealing temperature is 500° C., the annealing time is 4 hours, and the copper tube rough blank set annealing material is formed;

[0070] Step 5, the annealed copper tube blank set is stretched again on the coil-pulling vehicle until the copper wire is clamped on the inner wall of the copper tube blank and cannot move, thereby obtaining the desired double-hole copper tube.

[0071] The materials of the above-mentioned double-hole copper tube include copper strip material and copper wire material, wherein the copper strip material and the copper wire material have the same composition and preparation method, and are both prepared by using powder metallurgy.

[0072] Preferably, the method for preparing the material of the double-hole copper tube includes:

[0073] (1) Ball milling process: Copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres are mixed uniformly, and ball milled in a planetary ball mill with a ball-to-material ratio of 4:1, a ball milling time of 8 h, and a ball milling speed of 200 r / min. After the ball milling, a ball milled mixture is obtained; wherein, the weight ratio of copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres is 88.4:5.4:1.7:1.4; the purity of copper powder, zinc powder and iron powder is higher than 99.99%, and the particle size is all 10±2 μm.

[0074] (2) Molding process: The ball milled mixture is placed in a metal powder cold pressing machine for cold pressing at a pressure of 80 MPa for 2 h to obtain a molded blank;

[0075] (3) Sintering process: Place the formed blank in a high-temperature electric furnace, evacuate the vacuum, heat it to 500°C at a rate of 5°C / min, keep it at that temperature for 1 hour, continue to heat it to 900°C at a rate of 5°C / min, keep it at that temperature for 2 hours, and naturally cool it down to room temperature; then introduce inert gas as protective gas, heat it to 500°C at a rate of 10°C / min, keep it at that temperature for 2 hours, heat it to 900°C at a rate of 10°C / min, keep it at that temperature for 3 hours, first cool it down to 300°C at a rate of 5°C / min, and then naturally cool it down to room temperature to obtain the material of the double-hole copper tube.

[0076] Preferably, the preparation process of yttrium carbide-yttrium silicide composite microspheres comprises:

[0077] S1, dissolving yttrium nitrate in deionized water, the mass ratio of yttrium nitrate to deionized water is 5:100, stirring evenly to form an yttrium nitrate solution; dissolving sodium deoxycholate in deionized water, the mass ratio of sodium deoxycholate to deionized water is 5:100, stirring evenly to form a sodium deoxycholate solution;

[0078] S2, adding the sodium deoxycholate solution dropwise into the yttrium nitrate solution, the mass ratio of the sodium deoxycholate solution to the yttrium nitrate solution is 1:5.2, a large amount of floccules are generated, after sufficient stirring, the floccules are centrifuged and washed with pure water for at least three times, dried in a vacuum box, and crushed to obtain a yttrium deoxycholate compound;

[0079] S3, mixing yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water, wherein the mass ratio of yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water is 1:0.3:0.05:10, and the particle size of nano-yttrium silicide is 200-400 nm, and after sufficient stirring, a uniform first mixed slurry is formed;

[0080] S4, pouring the first mixed slurry into an AM100 planetary ball mill, with a ball-to-material ratio of 8:1, a ball milling time of 10 h, and a ball milling speed of 200 r / min. After the ball milling is completed, a second mixed slurry is obtained;

[0081] S5, pouring the second mixed slurry into an experimental spray dryer, adjusting the air inlet temperature to 170-190°C, the air outlet temperature to 70°C, the liquid inlet speed to 10mL / min, and spray drying to obtain a mixed microsphere powder;

[0082] S6, spread the mixed microsphere powder on the surface of the crucible, place the crucible in a high-temperature electric furnace, and heat and sinter in an inert gas atmosphere. The temperature is first raised to 400°C at a rate of 5°C / min, and after keeping it warm for 1 hour, it is continued to be heated to 1250°C at a rate of 10°C / min, and kept warm for 2 hours. After the temperature is raised and sintered, it is first cooled to 300°C at a rate of 5°C / min, and then naturally cooled to room temperature to obtain yttrium carbide-yttrium silicide composite microspheres with a diameter of 40-50μm.

[0083] Example 3

[0084] A production process for a double-hole copper tube comprises the following steps:

[0085] Step 1, welding the copper strip into a copper tube blank with an outer diameter of 6 mm and a tube wall thickness of 0.5 mm by a welding machine;

[0086] Step 2, the copper tube blank is stretched by a coil puller, the coefficient of each stretching is 0.7 mm, the stretching speed is 30 m / min, and a copper tube blank with an outer diameter of 4 mm is formed;

[0087] Step 3, cutting the copper tube blank into several sections, and then inserting a copper wire with a diameter of 1.8 mm from one end of the copper tube blank and leading it out from the other end, wherein the length of the copper wire is longer than the length of the copper tube after stretching, to form a copper tube blank set;

[0088] Step 4, placing the copper tube rough blank set under protective gas (hydrogen and nitrogen volume ratio is 1:10) for annealing, the annealing temperature is 600° C., the annealing time is 6 hours, and the copper tube rough blank set annealing material is formed;

[0089] Step 5, the annealed copper tube blank set is stretched again on the coil-pulling vehicle until the copper wire is clamped on the inner wall of the copper tube blank and cannot move, thereby obtaining the desired double-hole copper tube.

[0090] The materials of the above-mentioned double-hole copper tube include copper strip material and copper wire material, wherein the copper strip material and the copper wire material have the same composition and preparation method, and are both prepared by using powder metallurgy.

[0091] Preferably, the method for preparing the material of the double-hole copper tube includes:

[0092] (1) Ball milling process: Copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres are mixed uniformly and ball milled in a planetary ball mill with a ball-to-material ratio of 6:1, a ball milling time of 12 h, and a ball milling speed of 300 r / min. After the ball milling, a ball milled mixture is obtained; wherein the weight ratio of copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres is 91.2:6.6:2.5:2.8; the purity of copper powder, zinc powder and iron powder is higher than 99.99%, and the particle size is all 10±2 μm.

[0093] (2) Molding process: The ball milled mixture is placed in a metal powder cold pressing machine for cold pressing treatment at a pressure of 100 MPa and a cold pressing time of 4 h to obtain a molded blank;

[0094] (3) Sintering process: The formed blank is placed in a high-temperature electric furnace. After vacuuming, the temperature is increased to 600°C at a rate of 5°C / min, kept at this temperature for 1 hour, and then the temperature is increased to 1000°C at a rate of 5°C / min, kept at this temperature for 2 hours, and then naturally cooled to room temperature; then an inert gas is introduced as a protective gas, the temperature is increased to 600°C at a rate of 10°C / min, kept at this temperature for 2 hours, the temperature is increased to 1000°C at a rate of 10°C / min, kept at this temperature for 5 hours, and then the temperature is first decreased to 300°C at a rate of 5°C / min, and then naturally cooled to room temperature to obtain the material of the double-hole copper tube.

[0095] Preferably, the preparation process of yttrium carbide-yttrium silicide composite microspheres comprises:

[0096] S1, dissolving yttrium nitrate in deionized water, the mass ratio of yttrium nitrate to deionized water is 10:100, stirring evenly to form an yttrium nitrate solution; dissolving sodium deoxycholate in deionized water, the mass ratio of sodium deoxycholate to deionized water is 10:100, stirring evenly to form a sodium deoxycholate solution;

[0097] S2, adding the sodium deoxycholate solution dropwise into the yttrium nitrate solution, the mass ratio of the sodium deoxycholate solution to the yttrium nitrate solution is 1:6.4, a large amount of floccules are generated, after sufficient stirring, the floccules are centrifuged and washed with pure water for at least three times, dried in a vacuum box, and crushed to obtain a yttrium deoxycholate compound;

[0098] S3, mixing yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water, wherein the mass ratio of yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water is 1:0.5:0.1:10, and the particle size of nano-yttrium silicide is 200-400 nm, and after sufficient stirring, a uniform first mixed slurry is formed;

[0099] S4, pouring the first mixed slurry into an AM100 planetary ball mill, with a ball-to-material ratio of 10:1, a ball milling time of 15 h, and a ball milling speed of 300 r / min. After the ball milling is completed, a second mixed slurry is obtained;

[0100] S5, pouring the second mixed slurry into an experimental spray dryer, adjusting the air inlet temperature to 190°C, the air outlet temperature to 80°C, the liquid inlet speed to 20mL / min, and spray drying to obtain a mixed microsphere powder;

[0101] S6, spread the mixed microsphere powder on the surface of the crucible, place the crucible in a high-temperature electric furnace, and heat and sinter in an inert gas atmosphere. The temperature is first raised to 450°C at a rate of 5°C / min, and after keeping it warm for 2 hours, it is continued to be heated to 1350°C at a rate of 10°C / min, and kept warm for 4 hours. After the temperature is raised and sintered, it is first cooled to 300°C at a rate of 5°C / min, and then naturally cooled to room temperature to obtain yttrium carbide-yttrium silicide composite microspheres with a diameter of 40-50μm.

[0102] Comparative Example 1

[0103] A method for preparing a copper tube material, which differs from Example 1 in that no yttrium carbide-yttrium silicide composite microspheres are added during the material preparation process, and the remaining ball milling process, molding process, and sintering process are the same as Example 1.

[0104] Comparative Example 2

[0105] A method for preparing a copper tube material, which differs from Example 1 in that during the material preparation process, yttrium carbide-yttrium silicide composite microspheres are replaced with yttrium carbide powder, and the rest of the ball milling process, molding process, and sintering process are the same as Example 1.

[0106] Comparative Example 3

[0107] A method for preparing a copper tube material, which differs from Example 1 in that the yttrium carbide-yttrium silicide composite microspheres are replaced with yttrium powder during the material preparation process, and the amount of yttrium powder added is the same as the content of yttrium element in Example 1. The rest of the ball milling process, molding process, and sintering process are the same as in Example 1.

[0108] For the copper tube materials prepared in Example 1 and Comparative Examples 1-3, the properties of each copper tube material were tested respectively in order to explain more clearly, and the results are shown in the following table:

[0109]

[0110] It can be seen that Example 1 is a copper tube material prepared in the manner of the present invention, and its tensile strength is 298 MPa and its yield strength is 113 MPa, which are much higher than other control examples, indicating that both the mechanical strength and toughness are greatly improved, and cracking is not likely to occur, thereby enhancing the service life of the copper tube; and the recrystallization time is as high as 354°C, indicating that it can have more stable performance when high-temperature welding is required; the time to start corrosion is higher than 500h in a more severe acidic environment (pH=3.0), indicating that the corrosion resistance is also greatly improved, indicating that the copper tube material prepared in the manner of Example 1 of the present invention has more excellent performance.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A production process for a double-hole copper tube, characterized in that: The following steps are involved: Step 1, welding the copper strip into a copper tube blank with a relatively thick diameter by a welding machine; Step 2, the copper tube blank with a larger diameter is stretched by a coil puller to form a copper tube blank with a smaller diameter; Step 3, cutting the copper tube blank with a smaller diameter into several sections, and then inserting the copper wire into one end of the copper tube blank and leading it out from the other end to form a copper tube blank set; Step 4, placing the copper tube rough blank set under protective gas for annealing treatment to form an annealed material for the copper tube rough blank set; Step 5, the annealed material of the copper tube rough blank set is stretched again on the coil pulling car until the copper wire is clamped on the inner wall of the copper tube rough blank and cannot move, thereby obtaining the desired double-hole copper tube; The material of the double-hole copper tube includes a copper strip material and a copper wire material, wherein the copper strip material and the copper wire material have the same composition and preparation method, and are both prepared by using powder metallurgy; The preparation method of the material of the double-hole copper tube comprises: (1) Ball milling process: Copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres are mixed evenly and ball milled in a planetary ball mill with a ball-to-material ratio of 4-6:1, a ball milling time of 8-12 hours, and a ball milling speed of 200-300 r / min. After the ball milling is completed, a ball milled mixture is obtained; (2) Molding process: The ball milled mixture is placed in a metal powder cold pressing machine for cold pressing at a pressure of 80-100 MPa for 2-4 h to obtain a molded blank; (3) Sintering process: Place the formed blank in a high-temperature electric furnace, and after vacuuming, heat it to 500-600°C at a rate of 5°C / min, keep it warm for 1 hour, continue to heat it to 900-1000°C at a rate of 5°C / min, keep it warm for 2 hours, and naturally cool it to room temperature; then introduce inert gas as protective gas, heat it to 500-600°C at a rate of 10°C / min, keep it warm for 2 hours, heat it to 900-1000°C at a rate of 10°C / min, keep it warm for 3-5 hours, first cool it to 300°C at a rate of 5°C / min, and then naturally cool it to room temperature to obtain the material of the double-hole copper tube; The preparation process of yttrium carbide-yttrium silicide composite microspheres includes: S1, dissolving yttrium salt in deionized water, stirring evenly to form a yttrium salt solution; dissolving sodium deoxycholate in deionized water, stirring evenly to form a sodium deoxycholate solution; S2, adding the sodium deoxycholate solution dropwise into the yttrium salt solution, generating a large amount of flocs, stirring thoroughly, centrifuging the flocs, washing them with pure water at least three times, drying them in a vacuum oven, and crushing them to obtain a yttrium deoxycholate compound; S3, mixing the yttrium deoxycholate compound, nano-yttrium silicide, polyvinyl alcohol and deionized water, and stirring them sufficiently to form a uniform first mixed slurry; S4, pouring the first mixed slurry into a planetary ball mill, and obtaining a second mixed slurry after the ball milling is completed; S5, pouring the second mixed slurry into an experimental spray dryer, and spray drying to obtain a mixed microsphere powder; S6, spreading the mixed microsphere powder on the surface of the crucible, placing the crucible in a high-temperature electric furnace, heating and sintering under an inert gas atmosphere, and then cooling to room temperature to obtain yttrium carbide-yttrium silicide composite microspheres.

2. The production process of a double-hole copper tube according to claim 1, characterized in that: The outer diameter of the copper tube blank with a relatively large diameter is 4-6 mm, and the tube wall thickness is 0.1-0.5 mm.

3. The production process of a double-hole copper tube according to claim 1, characterized in that: The outer diameter of the copper tube blank with a relatively thin diameter is 2-4 mm, the coefficient of each stretching is 0.5-0.7 mm, and the stretching speed is 25-30 m / min.

4. The production process of a double-hole copper tube according to claim 1, characterized in that: The annealing temperature is 500-600° C., the annealing time is 4-6 hours, and the protective gas includes hydrogen and nitrogen in a volume ratio of 1:

10.

5. The production process of a double-hole copper tube according to claim 1, characterized in that: The diameter of the copper wire is 1.5-1.8 mm, and the length of the copper wire is longer than the length of the copper tube after stretching.

6. The production process of a double-hole copper tube according to claim 1, characterized in that: During the ball milling process, the weight ratio of copper powder, zinc powder, iron powder and yttrium carbide-yttrium silicide composite microspheres is 88.4-91.2:5.4-6.6:1.7-2.5:1.4-2.8; the purity of copper powder, zinc powder and iron powder is higher than 99.99%, and the particle size is 10±2μm.

7. The production process of a double-hole copper tube according to claim 1, characterized in that: The diameter of the yttrium carbide-yttrium silicide composite microspheres is 40-50 μm.

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