High-strength copper material containing scrap copper raw material and method for producing the same

Abstract

This invention discloses a high-strength copper material containing waste copper raw materials and its preparation method, relating to the field of recycled copper material technology. Specifically, it includes the following steps: S1: Weigh waste copper raw materials according to the formula, mix them completely to form a copper liquid, add a covering agent, heat to 1100~1120℃, add phosphorus copper for deoxidation, and let stand for 4~6 minutes; cool to 1030~1050℃, add composite additives, melt and stir to mix evenly; then adjust the alloy composition, and after passing the requirements, remove slag, keep warm, and horizontally continuously cast to obtain recycled copper ingots; S2: The recycled copper ingots are successively extruded and heat-treated to obtain extruded billets; S3: The extruded billets are drawn to obtain high-strength copper materials; The copper material prepared by this invention using waste copper as raw material has high strength, good machinability, and good surface quality.

Description

Technical Field

[0001] This invention relates to the field of recycled copper technology, specifically a high-strength copper material containing waste copper raw materials and its preparation method. Background Technology

[0002] Waste copper raw materials mainly come from discarded wires and cables, dismantled electronic components, and machining scraps. Recycling waste copper is an important way to alleviate copper resource shortages, reduce production costs, and achieve a circular economy. However, the sources of waste copper are complex and contain many impurities, making the recycling process difficult. Iron is the most common impurity element, which can form a hard and brittle iron-rich phase, creating stress concentration sources and making processing difficult. This results in poor mechanical properties of the recycled copper and can also cause scratches on the workpiece surface and wear on the die during subsequent drawing and forming processes.

[0003] In conclusion, solving the above problems and preparing a high-strength copper material using waste copper raw materials is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength copper material containing waste copper raw materials and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for preparing high-strength copper material containing scrap copper raw materials includes the following steps: S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add a covering agent, heat to 1100~1120℃, add phosphorus copper for deoxidation, and let stand for 4~6 minutes; cool to 1030~1050℃, add composite additives, melt and stir to mix evenly; then adjust the alloy composition, and after it is qualified, remove the slag, keep it at the temperature, and horizontally continuously cast to obtain recycled copper ingots. S2: The recycled copper ingot is successively extruded and heat-treated to obtain an extruded billet; S3: High-strength copper material is obtained by drawing extruded billets; The recycled copper ingots comprise the following elements by mass percentage: copper 54-56%, lead 2-3%, iron 0.7-0.9%, manganese 0.5-0.8%, nickel 0.3-0.6%, tin 0.3-0.5%, aluminum 0.1-0.2%, titanium 0.18-0.21%, cerium 0.1-0.18%, boron 0.0009-0.0018%, unavoidable impurities <0.5%, and the remainder being zinc.

[0006] Preferably, the amount of the composite additive is 0.4 to 0.6 wt% of the copper liquid; the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 2:1 to 1.2:3.5 to 4; the composite additive is wrapped in copper foil and pressed into the copper liquid.

[0007] Preferably, the amount of phosphor bronze added accounts for 0.02~0.05 wt% of the copper liquid; the amount of the covering agent added accounts for 0.3~0.7 wt% of the copper liquid; the covering agent includes sodium hexafluorosilicate, calcium carbonate, and sodium chloride in a mass ratio of 1~3:1:0.03~0.04.

[0008] Preferably, during the extrusion process, the temperature is 580~600℃ and the extrusion speed is 5~12mm / s.

[0009] Preferably, the heat treatment process is carried out at a temperature of 520~550℃ for 2~4 hours.

[0010] Preferably, during the drawing process, the drawing speed is 30~60m / min, and lubricant is used for lubrication and cooling during the drawing process; The lubricant comprises base oil, modified serpentine, and nano-copper composite material in a mass ratio of 100:0.1~0.2:0.2~0.5.

[0011] Preferred method for preparing the nano-copper composite material includes the following steps: (1) dispersing carbon nanotubes ultrasonically in Tris-HCl (pH=8.5) buffer solution, adding dopamine hydrochloride, stirring for 6-12 hours, filtering, washing, and drying to obtain polydopamine modified carbon nanotubes. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 12-24 hours, filter to obtain precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80-85℃ for 20-40 minutes. Filter, wash and dry to obtain nano-copper composite material.

[0012] Preferably, the raw materials for the polydopamine-modified carbon nanotubes include carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:3 to 5. The raw materials for the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate, and sodium hypophosphite in a mass ratio of 1:7~8:8~10.

[0013] A preferred embodiment of the modified serpentine preparation method includes the following steps: ultrasonically dispersing serpentine in a solvent, adding oleic acid, 4-dimethylaminopyridine, and N,N'-diisopropylcarbodiimide, ball milling at 25-30°C for 12-24 hours, filtering, washing, and drying to obtain modified serpentine; The modified serpentine raw materials include serpentine, oleic acid, 4-dimethylaminopyridine, and N,N'-diisopropylcarbodiimide in a mass ratio of 5:2~3:0.05~0.06:1.3~1.4.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention uses scrap copper as raw material and introduces cerium, boron and titanium as composite additives through element regulation, which significantly improves the strength and machinability of copper materials. At the same time, modified serpentine and nano copper composite materials are introduced as lubricating additives into the base lubricating oil used in the drawing process, which significantly improves the friction reduction and wear resistance of the drawing process, thereby improving the surface quality of copper materials and reducing die wear.

[0015] Among them, the cerium added to the composite additive can form a high-melting-point compound with lead, and the introduced titanium can also form a high-melting-point compound FeTi2 with iron. This can promote grain refinement and maintain the hard point morphology at high drawing temperatures, assist in rolling lubrication, reduce mold adhesion, and improve the surface quality of the material. Using cerium, boron, and titanium in a specific ratio as composite additives can effectively cause lattice distortion in recycled copper ingots, refine the crystal phase, and improve the strength of copper materials.

[0016] The preparation method of the nano-copper composite material is to prepare a polydopamine modified layer in situ on the surface of carbon nanotubes, and then use sodium hypophosphite as a reducing agent to load nano-copper particles in situ on the surface of polydopamine modified carbon nanotubes; the preparation method of the modified serpentine is to prepare it by hydroxyl esterification of oleic acid and serpentine surface under the catalysis of 4-dimethylaminopyridine and N,N'-diisopropylcarbodiimide.

[0017] Among them, nano-copper possesses low shear strength and self-healing properties, which can repair surface damage at the friction interface by filling micro-pits and reduce direct metal contact, thereby improving lubrication performance. However, nano-copper is prone to agglomeration and has poor dispersibility. This invention improves dispersibility by in-situ loading nano-copper onto carbon nanotubes with polydopamine, while also providing active film-forming sites for the friction pair and shortening the break-in period. Carbon nanotubes can provide a rolling bearing effect to reduce friction and have excellent thermal conductivity to prevent local overheating that could lead to lubrication failure. Meanwhile, serpentine has a layered silicate structure and good adsorption properties, which can form a physically adsorbed protective film on the friction surface, playing a role in solid lubrication and friction reduction. By compounding nano-copper composite materials and serpentine, a synergistic lubrication effect can be achieved. Nano-copper, through the anchoring, dispersion, and directional transfer effects of carbon nanotubes, effectively fills and repairs microscopic defects on the friction surface, and works synergistically with serpentine to isolate the die from direct contact with the workpiece, thereby improving the surface quality of the drawing process and the die's service life. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the following quantities are by weight. There are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary components include: carbon nanotubes: length 10~30μm, diameter 20~30nm; CAS number of dopamine hydrochloride: 62-31-7; CAS number of copper acetate: 6046-93-1; CAS number of sodium hypophosphite: 13933-52-3; copper phosphate: phosphorus content 8%; cerium: particle size 0.1~0.25mm; calcium boride: particle size 10~50μm; titanium: particle size 3mm; serpentine: particle size 1~5μm; base lubricating oil: model CD 5W / 40.

[0020] In the following examples, parts refer to parts by weight, and all raw materials mentioned above and others not mentioned are commercially available.

[0021] The scrap copper used comes from sources including leaded brass processing waste and scrap cables.

[0022] The covering agent includes sodium hexafluorosilicate, calcium carbonate, and sodium chloride in a mass ratio of 2:1:0.03.

[0023] The preparation method of modified serpentine includes the following steps: serpentine is ultrasonically dispersed in toluene, oleic acid, 4-dimethylaminopyridine, and N,N'-diisopropylcarbodiimide are added, ball milled at 25°C for 12 hours, filtered, washed, and dried to obtain modified serpentine; the raw materials for modified serpentine include serpentine, oleic acid, 4-dimethylaminopyridine, and N,N'-diisopropylcarbodiimide in a mass ratio of 5:2.5:0.05:1.35.

[0024] Example 1: A method for preparing high-strength copper material containing scrap copper raw materials includes the following steps: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.5wt% of composite additive, melt and stir to mix evenly; then adjust the alloy composition, after which, remove slag, keep warm, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 2:1.1:3.7; the composite additive is wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano-copper composite material in a mass ratio of 100:0.15:0.3; The recycled copper ingot comprises the following elements by mass percentage: 54.75% copper, 2.62% lead, 0.74% iron, 0.71% manganese, 0.52% nickel, 0.33% tin, 0.194% titanium, 0.143% cerium, 0.00136% boron, with unavoidable impurities <0.5%, and the remainder being zinc.

[0025] Example 2: A method for preparing a high-strength copper material containing scrap copper raw materials includes the following steps: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.3wt% of composite additive, melt and stir to mix evenly; then adjust the alloy composition, after which, remove slag, keep warm, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 2:1.1:3.7; the composite additive is wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano-copper composite material in a mass ratio of 100:0.1:0.5; The recycled copper ingot comprises the following elements by mass percentage: 55.28% copper, 2.15% lead, 0.82% iron, 0.64% manganese, 0.35% nickel, 0.46% tin, 0.183% titanium, 0.115% cerium, 0.00098% boron, with unavoidable impurities <0.5%, and the remainder being zinc.

[0026] Example 3: A method for preparing a high-strength copper material containing scrap copper raw materials includes the following steps: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.7wt% of composite additives, melt and stir to mix evenly; then adjust the alloy composition, and after it is qualified, remove the slag, keep it at the temperature, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additives include cerium, calcium boride, and titanium in a mass ratio of 2:1.1:3.7; the composite additives are wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano-copper composite material in a mass ratio of 100:0.2:0.2; The recycled copper ingot comprises the following elements by mass percentage: 55.63% copper, 2.13% lead, 0.79% iron, 0.56% manganese, 0.41% nickel, 0.44% tin, 0.201% titanium, 0.177% cerium, 0.00162% boron, with unavoidable impurities <0.5%, and the remainder being zinc.

[0027] Comparative Example 1: Based on Example 1, without adding composite additives, and with the rest of the process unchanged, as follows: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the waste copper raw materials according to the formula, mix them and melt them completely to form copper liquid. Add 0.5wt% of the copper liquid covering agent, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes. Cool down to 1040℃. Then adjust the alloy composition. After it is qualified, remove the slag, keep it warm, and horizontally continuously cast to obtain recycled copper ingots. S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano-copper composite material in a mass ratio of 100:0.15:0.3.

[0028] Comparative Example 2: Based on Example 1, cerium was replaced with lanthanum, while the rest of the process remained unchanged, as follows: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.5wt% of composite additive, melt and stir to mix evenly; then adjust the alloy composition, and after it is qualified, remove the slag, keep it at the temperature, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additive includes lanthanum, calcium boride, and titanium in a mass ratio of 2:1.1:3.7; the composite additive is wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano-copper composite material in a mass ratio of 100:0.15:0.3.

[0029] Comparative Example 3: Based on Example 1, the proportions of the components in the composite additive were adjusted, while the rest of the process remained unchanged, as follows: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.5wt% of composite additive, melt and stir to mix evenly; then adjust the alloy composition, after which, remove slag, keep warm, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 1:1:1; the composite additive is wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano-copper composite material in a mass ratio of 100:0.15:0.3.

[0030] Comparative Example 4: Based on Example 1, without adding modified serpentine, and with the rest of the process unchanged, as follows: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.5wt% of composite additive, melt and stir to mix evenly; then adjust the alloy composition, after which, remove slag, keep warm, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 2:1.1:3.7; the composite additive is wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil and nano-copper composite material with a mass ratio of 100:0.45.

[0031] Comparative Example 5: Based on Example 1, the nano-copper does not use carbon nanotubes for support, and the other processes remain unchanged, as follows: Step 1: Preparation of nano copper: (1) Add copper acetate to anhydrous ethanol and mix evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 min. Filter, wash and dry to obtain nano copper. The raw materials of the nano copper include copper acetate and sodium hypophosphite in a mass ratio of 7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.5wt% of composite additive, melt and stir to mix evenly; then adjust the alloy composition, after which, remove slag, keep warm, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 2:1.1:3.7; the composite additive is wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano copper in a mass ratio of 100:0.15:0.3.

[0032] Comparative Example 6: Based on Example 1, the amounts of modified serpentine and nano-copper composite materials were exchanged, while the other processes remained unchanged, as follows: Step 1: Preparation of nano-copper composite material: (1) Carbon nanotubes were ultrasonically dispersed in Tris-HCl (pH=8.5) buffer solution, dopamine hydrochloride was added, the mixture was stirred and reacted for 8 hours, filtered, washed and dried to obtain polydopamine modified carbon nanotubes; wherein, the raw materials of the polydopamine modified carbon nanotubes included carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:4. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 24 hours, filter to obtain a precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80°C for 30 minutes. Filter, wash and dry to obtain nano-copper composite material. The raw materials of the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate and sodium hypophosphite in a mass ratio of 1:7.5:9. Step Two: Preparation of High-Strength Copper Material S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add 0.5wt% of a covering agent to the copper liquid, heat to 1100℃, add 0.04wt% of phosphorus copper for deoxidation, and let stand for 5 minutes; cool to 1040℃ and add 0.5wt% of composite additive, melt and stir to mix evenly; then adjust the alloy composition, after which, remove slag, keep warm, and horizontally continuously cast to obtain recycled copper ingots; wherein, the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 2:1.1:3.7; the composite additive is wrapped in copper foil and pressed into the copper liquid; S2: The recycled copper ingot is extruded at 590℃ at a speed of 8mm / s and then heat-treated at 550℃ for 3 hours to obtain the extruded billet; S3: High-strength copper material is obtained by drawing the extruded billet under the condition of lubrication and cooling by lubricating fluid at a drawing speed of 40m / min; wherein, the lubricating fluid includes base oil, modified serpentine and nano-copper composite material in a mass ratio of 100:0.3:0.15.

[0033] Performance Test 1: The tensile strength of the samples from Examples 1-3 and Comparative Examples 1-3 was tested according to GB / T 34505. The sample diameter was 6 mm, full cross-section specimens were used, and the gauge length was 100 mm. The experimental data are shown in Table 1.

[0034] Table 1

[0035] As shown in Table 1, Comparative Example 1, without the addition of composite additives, resulted in grain coarsening, lead phase softening, and a significant decrease in tensile strength. Comparative Example 2, by replacing cerium with lanthanum, reduced the effect of grain refinement and the formation of a uniform strengthening phase, resulting in a decrease in tensile strength. Comparative Example 3, by adjusting the proportion of components in the composite additives, affected the effective formation and distribution of the strengthening phase, weakening the synergistic strengthening effect.

[0036] Performance Test 2: The surface nanomechanical properties of Examples 1-3 and Comparative Examples 4-6 were tested using a nanoindenter. A triangular pyramidal diamond indenter was used, and a continuous stiffness mode was adopted. The maximum indentation depth was 2000 nm, and the maximum indentation depth required to be held for 15 s. The loading speed was 0.5 mN / s, and the average hardness during the steady-state phase was measured. The experimental data are shown in Table 2.

[0037] Table 2

[0038] As shown in Table 2, in Comparative Example 4, without the addition of modified serpentine, the lubrication system lacked the layered physical adsorption film of serpentine, resulting in decreased friction reduction and wear resistance. This led to increased surface friction during drawing, generating more microscopic defects and uneven work hardening, thus reducing the hardness and deteriorating the surface quality. In Comparative Example 5, without the use of carbon nanotubes for loading, the nano-copper agglomerated and lacked the synergistic lubrication of serpentine, resulting in decreased hardness. In Comparative Example 6, by exchanging the amount of modified serpentine and nano-copper composite material introduced, the content of nano-copper decreased, making it difficult to effectively fill pits and lubricate, thus reducing the hardness.

[0039] Conclusion: The beneficial effects achieved by this invention are as follows: This invention uses scrap copper as raw material and introduces cerium, boron, and titanium as composite additives through element regulation, which significantly improves the strength and machinability of copper materials. At the same time, the introduction of modified serpentine and nano-copper composite materials as lubricating additives into the base lubricating oil used in the drawing process significantly improves the friction reduction and wear resistance of the drawing process, thereby improving the surface quality of copper materials and reducing die wear.

[0040] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-strength copper materials containing scrap copper raw materials, characterized in that: Includes the following steps: S1: Weigh the scrap copper raw materials according to the formula, mix them completely to form a copper liquid, add a covering agent, heat to 1100~1120℃, add phosphorus copper for deoxidation, and let stand for 4~6 minutes; cool to 1030~1050℃, add composite additives, melt and stir to mix evenly; then adjust the alloy composition, and after it is qualified, remove the slag, keep it at the temperature, and horizontally continuously cast to obtain recycled copper ingots. S2: The recycled copper ingot is successively extruded and heat-treated to obtain an extruded billet; S3: High-strength copper material is obtained by drawing extruded billets; The recycled copper ingots comprise the following elements by mass percentage: copper 54-56%, lead 2-3%, iron 0.7-0.9%, manganese 0.5-0.8%, nickel 0.3-0.6%, tin 0.3-0.5%, aluminum 0.1-0.2%, titanium 0.18-0.21%, cerium 0.1-0.18%, boron 0.0009-0.0018%, unavoidable impurities <0.5%, and the remainder being zinc.

2. The method for preparing high-strength copper material containing scrap copper raw materials according to claim 1, characterized in that: The amount of the composite additive added accounts for 0.4~0.6 wt% of the copper liquid; the composite additive includes cerium, calcium boride, and titanium in a mass ratio of 2:1~1.2:3.5~4; the composite additive is wrapped in copper foil and pressed into the copper liquid.

3. The method for preparing high-strength copper material containing scrap copper raw materials according to claim 1, characterized in that: The amount of phosphor bronze added accounts for 0.02~0.05 wt% of the copper liquid; the amount of the covering agent added accounts for 0.3~0.7 wt% of the copper liquid; the covering agent includes sodium hexafluorosilicate, calcium carbonate, and sodium chloride in a mass ratio of 1~3:1:0.03~0.

04.

4. The method for preparing high-strength copper material containing scrap copper raw materials according to claim 1, characterized in that: During the extrusion process, the temperature is 580~600℃ and the extrusion speed is 5~12mm / s.

5. The method for preparing high-strength copper material containing scrap copper raw materials according to claim 1, characterized in that: The heat treatment process is carried out at a temperature of 520~550℃ for 2~4 hours.

6. The method for preparing high-strength copper material containing scrap copper raw materials according to claim 1, characterized in that: During the drawing process, the drawing speed is 30~60m / min, and lubricant is used for lubrication and cooling during the drawing process; The lubricant comprises base oil, modified serpentine, and nano-copper composite material in a mass ratio of 100:0.1~0.2:0.2~0.

5.

7. The method for preparing a high-strength copper material containing scrap copper raw materials according to claim 6, characterized in that: The preparation method of the nano-copper composite material includes the following steps: (1) Disperse carbon nanotubes ultrasonically in Tris-HCl (pH=8.5) buffer solution, add dopamine hydrochloride, stir for 6~12h, filter, wash, dry, and obtain polydopamine modified carbon nanotubes. (2) Disperse polydopamine-modified carbon nanotubes in anhydrous ethanol, add copper acetate and mix evenly. After standing for 12-24 hours, filter to obtain precipitate. Add the precipitate to anhydrous ethanol and ultrasonically disperse evenly. Add sodium hypophosphite-ethanol solution and stir at 80-85℃ for 20-40 minutes. Filter, wash and dry to obtain nano-copper composite material.

8. The method for preparing a high-strength copper material containing scrap copper raw materials according to claim 7, characterized in that: The raw materials for the polydopamine-modified carbon nanotubes include carbon nanotubes and dopamine hydrochloride in a mass ratio of 1:3 to 5. The raw materials for the nano-copper composite material include polydopamine-modified carbon nanotubes, copper acetate, and sodium hypophosphite in a mass ratio of 1:7~8:8~10.

9. The method for preparing a high-strength copper material containing scrap copper raw materials according to claim 6, characterized in that: The preparation method of the modified serpentine includes the following steps: ultrasonically dispersing serpentine in a solvent, adding oleic acid, 4-dimethylaminopyridine, and N,N'-diisopropylcarbodiimide, ball milling at 25~30℃ for 12~24h, filtering, washing, and drying to obtain modified serpentine; The modified serpentine raw materials include serpentine, oleic acid, 4-dimethylaminopyridine, and N,N'-diisopropylcarbodiimide in a mass ratio of 5:2~3:0.05~0.06:1.3~1.

4.

10. The high-strength copper material prepared by the method of preparing high-strength copper material containing waste copper raw material according to any one of claims 1 to 9.

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