Novel corrosion-resistant dezincification-resistant environment-friendly lead-free copper alloy and preparation method thereof

Abstract

The invention discloses a novel corrosion-resistant dezincification-resistant environment-friendly lead-free copper alloy and a preparation method thereof.The copper alloy is composed of, by weight, 62%-64.5% of copper, 0%-0.1% of lead, 0.55%-0.70% of aluminum, 0.05%-0.15% of tin, 0-0.02% of nickel, 0%-0.15% of iron, 0.1%-0.14% of arsenic and the balance Zn and inevitable impurities, the sum of the impurities is smaller than or equal to 0.2%, and single impurities are smaller than or equal to 0.02%. Compared with the prior art, the copper alloy has the beneficial effects that the prepared copper alloy is low in preparation cost, low in lead, excellent in corrosion resistance, dezincification resistance and cutting performance, environmentally friendly and good in application prospect.

Description

Technical Field

[0001] This invention relates to the field of lead-free copper alloy preparation. More specifically, this invention relates to a novel corrosion-resistant, dezincification-resistant, environmentally friendly lead-free copper alloy and its preparation method. Background Technology

[0002] With societal development, advocating for green and environmentally friendly practices is now mainstream and increasingly attracting international attention. The global movement to ban lead has placed lead-free technology for bathroom products on the agenda of countries worldwide. Following the enactment of California's 2010 lead ban on drinking water pipes, the movement to ban lead in bathroom products has gradually unfolded, and the Chinese market is gradually aligning with international standards. To improve the adaptability of their products and avoid technical barriers to trade during exports, domestic manufacturers must raise their awareness of lead-free bathroom products to quickly adapt to international market requirements; otherwise, their products will lose market competitiveness and be placed in a passive position in increasingly fierce international competition. Therefore, the gradual realization of lead-free bathroom products globally is imperative, and researchers are actively seeking lead-free alternatives to traditional leaded brass.

[0003] Due to variations in water quality across countries, countries like Japan, Australia, and Germany require bathroom products to be resistant to zinc desulfurization. This results in differences in material requirements for bathroom products across different regions and countries; some require low lead content, others require zinc desulfurization resistance, and still others require both. To meet these diverse requirements, manufacturers need the capacity to produce multiple materials. This presents significant challenges to production and sales. Therefore, developing new materials that are both low in lead and possess corrosion resistance and zinc desulfurization resistance has become a pressing need and a key technical challenge for bathroom product manufacturers. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0005] Another objective of this invention is to provide a novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy and its preparation method. This alloy has low preparation cost, low lead content, and excellent corrosion resistance, dezincification resistance, and machinability. It is also environmentally friendly and has good application prospects.

[0006] To achieve these objectives and other advantages according to the present invention, a novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy is provided, comprising the following weight percentages: copper 62%-64.5%, lead 0%-0.1%, aluminum 0.55%-0.70%, tin 0.05%-0.15%, nickel 0-0.02%, iron 0%-0.15%, arsenic 0.1%-0.14%, with the balance being Zn and unavoidable impurities, the total of which is ≤0.2%.

[0007] A method for preparing a novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy includes the following steps: S1. Weigh out copper, zinc, tin, copper-30% iron alloy, aluminum, arsenic, nickel and the modifying element, wherein the modifying element is at least one of manganese, titanium, silicon and rare earth elements; S2. Place copper and copper-30% iron alloy at the bottom of the induction furnace, cover with charcoal, heat to 1050~1150℃ until all materials are melted, add slag remover, and filter out the surface slag. S3. Adjust the temperature to 1030~1080℃, add zinc to the material obtained in S2 and quickly press it into the bottom of the furnace. Stir thoroughly after it melts. S4. Add tin and arsenic to the material obtained in S3, stir thoroughly until homogeneous, then add aluminum and nickel, and stir thoroughly until homogeneous. S5. Add the modifying element to the alloy liquid obtained in S4, heat to 1080~1150℃, spray fire, stir and keep warm for 2-3 minutes. S6. Place the material obtained in S5 at 1000~1050℃ and keep it at that temperature for 10-20 minutes to make the alloy uniform and the impurities float up. Filter out the scum and impurities. S7. Heat the material obtained in S6 to 1050~1100℃, remove it from the furnace and cast it into ingots. After cooling, it becomes a copper alloy.

[0008] Preferably, step S2 specifically involves: alternately spreading copper and copper-30% ferroalloy on the bottom of an induction furnace to form a 3-5 layer composite structure, with each layer controlled to a thickness of 5-8 cm. Each layer of copper / copper-30% ferroalloy is covered with a 1.5-2.5 cm thick layer of modified charcoal, which is made from natural charcoal soaked in a 5% boric acid solution and then dried. A slag remover is added, and the temperature is then raised to 1100-1120°C and held for 15-20 minutes. The slag remover is a CaO-Al2O3-MgO ternary system, composed of 45% CaO, 35% Al2O3, and 20% MgO. The amount of CaO-Al2O3-MgO added is 0.4-0.6% of the total weight of the copper and copper-30% ferroalloy.

[0009] Preferably, the preparation of the modified charcoal layer includes the following steps: A1. Crush natural oak charcoal to a particle size of 2-5mm, place it in a 5% boric acid solution at 55-65℃, and perform ultrasonic-assisted soaking at a liquid-solid ratio of 3:1. The ultrasonic conditions are: ultrasonic frequency 40kHz, ultrasonic power 200W, and treatment for 30-45 minutes. A2. The natural oak charcoal soaked in A1 was dried by vacuum drying to obtain modified charcoal. The vacuum drying conditions were: vacuum degree -0.1MPa, temperature 120±5℃, drying time 2 hours. A3. After vacuum drying in A2, a 0.3-0.5% nano-SiO2 dispersion is uniformly sprayed onto the surface of the charcoal to form a composite coating with a thickness of 1-2 μm, thus obtaining the modified charcoal layer; wherein, the nano-SiO2 dispersion has a particle size of 20-50 nm and the dispersion medium is ethanol.

[0010] Preferably, the preparation of the CaO-Al2O3-MgO ternary system is specifically as follows: B1. Raw material pretreatment: CaO, Al2O3 and MgO are ground to a particle size ≤5μm and placed in a vacuum drying oven at 150℃ for 4 hours to obtain pretreated raw materials; B2. Nanocomposite modification: The pretreated raw materials are mixed in a ratio of 45:35:20, and 2% of nano TiO2 and 1% of graphene nanosheets are added by mass. The composite powder is formed by high-energy ball milling. The conditions for high-energy ball milling are: rotation speed 800 rpm and time 2 hours.

[0011] Preferably, the process also includes step B3, which specifically involves: the sludge remover further comprising 0.5% of a surfactant by mass, which is then granulated into spherical particles with a particle size of 1-3 mm by spray granulation, wherein the surfactant is polyethylene glycol octylphenyl ether.

[0012] Preferably, the slag remover further comprises 0.5% surfactant by mass, and the specific preparation method for producing spherical particles with a particle size of 1-3 mm by spray granulation is as follows: C1. Surfactant pretreatment: Polyethylene glycol octylphenyl ether and 15% by mass of nano-SiO2 are ultrasonically dispersed in a 50°C water bath. The ultrasonic conditions are: frequency 40kHz, power 300W, ultrasonic for 30 minutes to form a stable mixed solution, which is the pretreated surfactant. C2. Spray granulation: The pretreated surfactant is sprayed onto the composite powder in B2 in a pressure spray drying tower, and narrow-distribution particles with a particle size of 1-3 mm are obtained by fluidized bed classification and screening; then ammonia gas is immediately introduced to form an aminated layer on the particle surface; wherein, the ammonia gas flow rate is 5 L / min. The conditions for processing in the pressure spray drying tower are as follows: compressed air pressure 0.6MPa, feed rate 50mL / min, drying tower inlet air temperature 220±5℃, and outlet air temperature 110±5℃.

[0013] Preferably, the altering element is a combination of manganese, titanium, silicon and mixed rare earth elements, wherein the mass ratio of manganese, titanium, silicon and mixed rare earth elements is 3:2:1:1; the mixed rare earth elements are lanthanum and cerium in a mass ratio of 2:1. Manganese powder, titanium powder, silicon powder, and mixed rare earth element powder were pretreated separately and dried in a vacuum environment of 300℃ and -0.09MPa for 1 hour to remove surface moisture and impurities. Then, the treated powders were thoroughly mixed to make granular modifiers with a particle size of 1-3mm to improve their dispersibility in the alloy liquid.

[0014] Preferably, in step S5, after heating to 1120-1130℃, oxygen-enriched flaming technology is used for flaming, wherein the flaming gas is a mixture of oxygen and propane, the volume ratio of oxygen to propane is 5:1, the flaming pressure is 0.2-0.3MPa, and the flaming time is 1 minute.

[0015] The present invention has at least the following beneficial effects: This invention provides a corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy. Utilizing the principle of multi-element, low-volume alloying, the formula of existing copper alloys is optimized. Specifically, the combined action of elements such as arsenic and silicon replaces lead in ordinary brass, developing a new low-lead, corrosion-resistant, dezincification-resistant brass material for bathroom products. Simultaneously, by utilizing brass recrystallization technology and conducting in-depth research on brass annealing processes and parameters, a globally applicable new material that is both low in lead and possesses dezincification resistance is developed. Furthermore, based on the high-temperature phase transformation and recrystallization laws of brass, a secondary annealing technology is employed, giving the low-lead faucets excellent dezincification resistance, reducing subsequent processing allowances, saving materials, and meeting current expectations for added value in health and environmental protection, leading to a safer, more comfortable, and worry-free lifestyle.

[0016] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0017] Figure 1 Metallographic image of the copper alloy prepared in Example 1; Figure 2 Metallographic image of the copper alloy prepared in Example 2; Figure 3 Metallographic image of the copper alloy prepared in Example 3; Figure 4 Metallographic image of the copper alloy prepared in Comparative Example 1. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0019] This invention provides a novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy, with the following weight percentage composition: copper 62%-64.5%, lead 0%-0.1%, aluminum 0.55%-0.70%, tin 0.05%-0.15%, nickel 0-0.02%, iron 0%-0.15%, arsenic 0.1%-0.14%, and the balance being Zn and unavoidable impurities, with the total impurities ≤0.2%, and each individual impurity ≤0.02%. The novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy prepared using the above technical solution is both low in lead and has dezincification resistance, making it a globally applicable new material.

[0020] This invention also provides a method for preparing a novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy, characterized by comprising the following steps: S1. Weigh out copper, zinc, tin, copper-30% iron alloy, aluminum, arsenic, nickel and the modifying element, wherein the modifying element is at least one of manganese, titanium, silicon and rare earth elements; S2. Place copper and copper-30% iron alloy at the bottom of the induction furnace, cover with charcoal, heat to 1050~1150℃ until all materials are melted, add slag remover, and filter out the surface slag. S3. Adjust the temperature to 1030~1080℃, add zinc to the material obtained in S2 and quickly press it into the bottom of the furnace. Stir thoroughly after it melts. S4. Add tin and arsenic to the material obtained in S3, stir thoroughly until homogeneous, then add aluminum and nickel, and stir thoroughly until homogeneous. S5. Add the modifying element to the alloy liquid obtained in S4, heat to 1080~1150℃, spray fire, stir and keep warm for 2-3 minutes. S6. Place the material obtained in S5 at 1000~1050℃ and keep it at that temperature for 10-20 minutes to make the alloy uniform and the impurities float up. Filter out the scum and impurities. S7. Heat the material obtained in S6 to 1050~1100℃, remove it from the furnace and cast it into ingots. Cool it to obtain copper alloy. The beneficial effects of adopting the above technical solution are as follows: a novel method for preparing a corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy is provided. The existing copper alloy formula is optimized. Specifically, utilizing the principle of multi-element, small-quantity alloying, the combined action of elements such as arsenic and silicon is used to replace lead in ordinary brass, developing a new low-lead, corrosion-resistant, dezincification-resistant brass material for bathroom products. Simultaneously, by utilizing brass recrystallization technology and conducting in-depth research on the annealing process and parameters of brass, a new globally applicable material that is both low in lead and possesses dezincification resistance is developed. Furthermore, based on the high-temperature phase transformation and recrystallization laws of brass, a secondary annealing technology is adopted, enabling low-lead faucets to have excellent dezincification resistance, reducing subsequent processing allowances, saving materials, and meeting current expectations for added value related to health and environmental protection, thus promoting a safer, more comfortable, and worry-free lifestyle.

[0021] In another technical solution, step S2 specifically involves: alternately spreading copper and copper-30% ferroalloy on the bottom of an induction furnace to form a 3-5 layer composite structure, with each layer controlled to a thickness of 5-8 cm. Each layer of copper / copper-30% ferroalloy is covered with a 1.5-2.5 cm thick layer of modified charcoal, which is made from natural charcoal soaked in a 5% boric acid solution and then dried. A slag-removing agent is added, and the temperature is then raised to 1100-1120℃ and held for 15-20 minutes. The slag-removing agent is a CaO-Al2O3-MgO ternary system, composed of 45% CaO, 35% Al2O3, and 20% MgO. The amount of CaO-Al2O3-MgO added is 0.4-0.6% of the total weight of the copper and copper-30% ferroalloy. The beneficial effects of this technical solution are as follows: by alternately layering copper and copper-30% iron alloy to form a metallurgical bonding interface, Fe segregation is suppressed, and the uniformity of Fe distribution in the final Cu-Fe solid solution is improved by more than 40% (compared to the traditional mixed loading method); by using boric acid-treated charcoal, which releases B2O3 at high temperature and reacts with metal oxides to generate low-melting-point slag, the slag removal efficiency can be significantly improved; and by using a CaO-Al2O3-MgO ternary system as a slag remover, compared with the traditional single CaO-based slag remover, the slag remover of this invention can simultaneously remove impurities such as S and P, significantly improving the desulfurization rate and avoiding fluoride pollution.

[0022] In another technical solution, the preparation of the modified charcoal layer includes the following steps: A1. Crush natural oak charcoal to a particle size of 2-5mm, place it in a 5% boric acid solution at 55-65℃, and perform ultrasonic-assisted soaking at a liquid-solid ratio of 3:1. The ultrasonic conditions are: ultrasonic frequency 40kHz, ultrasonic power 200W, and treatment for 30-45 minutes. A2. The natural oak charcoal soaked in A1 was dried by vacuum drying to obtain modified charcoal. The vacuum drying conditions were: vacuum degree -0.1MPa, temperature 120±5℃, drying time 2 hours. A3. Uniformly spray 0.3-0.5% nano-SiO2 dispersion onto the surface of the charcoal after vacuum drying in A2 to form a composite coating with a thickness of 1-2 μm, thus obtaining the modified charcoal layer; wherein, the particle size of the nano-SiO2 dispersion is 20-50 nm, and the dispersion medium is ethanol; The beneficial effects of adopting the above technical solution are as follows: the ultrasonic cavitation effect accelerates the penetration of boric acid into the pores of charcoal, thereby improving the uniformity of boron distribution in the charcoal and increasing the rate of B2O3 release at high temperatures; nano-SiO2 forms a high-temperature resistant barrier on the charcoal surface, significantly increasing the antioxidant temperature of the modified charcoal and effectively extending the protection time of the coating layer; the moisture evaporation rate is rapidly increased under vacuum conditions, while inhibiting boric acid crystallization and agglomeration, ensuring that boron exists in a molecularly dispersed state in the charcoal pores as much as possible; overall, the modified charcoal layer lowers the melting point of the slag phase and increases the mobile phase, improving the slag removal speed and the removal rate of inclusions; the nano-SiO2 coating reduces the high-temperature volatilization of boric acid and avoids fluorine pollution associated with traditional fluorine-containing coatings.

[0023] In another technical solution, the preparation of the CaO-Al2O3-MgO ternary system is specifically as follows: B1. Raw material pretreatment: CaO, Al2O3 and MgO are ground to a particle size ≤5μm and placed in a vacuum drying oven at 150℃ for 4 hours to obtain pretreated raw materials; B2. Nanocomposite modification: The pretreated raw materials are mixed in a ratio of 45:35:20, and 2% of nano TiO2 and 1% of graphene nanosheets are added. The composite powder is formed by high-energy ball milling. The conditions for high-energy ball milling are: 800 rpm and 2 hours. The beneficial effects of this technical solution are that TiO2 promotes the oxidation of S through photocatalysis, graphene enhances the conductivity of slag, and the desulfurization rate is further improved. The slag cleaner achieves a dual breakthrough in deep impurity removal and greening of the process in copper alloy smelting, laying the foundation for the preparation of high-quality lead-free copper alloys.

[0024] In another technical solution, the slag remover further includes a surfactant comprising 0.5% of the total mass, which is produced into spherical particles with a particle size of 1-3 mm by spray granulation. The surfactant is polyethylene glycol octylphenyl ether. Specifically, the total mass here refers to the total mass of the composite powder, that is, the amount of surfactant used is 0.5% of the total mass of the composite powder. The beneficial effects of this technical solution are that the introduction of surfactants improves the dispersibility of slag remover particles in the melt, increases the specific surface area, and significantly enhances the reactivity.

[0025] In another technical solution, the slag-removing agent further comprises a surfactant accounting for 0.5% of the total mass, and the specific preparation method for producing spherical particles with a particle size of 1-3 mm by spray granulation is as follows: C1. Surfactant pretreatment: Polyethylene glycol octylphenyl ether and 15% by mass of nano-SiO2 are ultrasonically dispersed in a 50°C water bath. The ultrasonic conditions are: frequency 40kHz, power 300W, ultrasonic for 30 minutes to form a stable mixed solution, which is the pretreated surfactant. C2. Spray granulation: The pretreated surfactant is sprayed onto the composite powder in B2 in a pressure spray drying tower, and narrow-distribution particles with a particle size of 1-3 mm are obtained by fluidized bed classification and screening; then ammonia gas is immediately introduced to form an aminated layer on the particle surface; wherein, the ammonia gas flow rate is 5 L / min. The conditions for processing in the pressure spray drying tower are as follows: compressed air pressure 0.6MPa, feed rate 50mL / min, drying tower inlet air temperature 220±5℃, and outlet air temperature 110±5℃.

[0026] The beneficial effects of adopting the above technical solution are that SiO2 nanoparticles are physically adsorbed and anchored on the polyethylene glycol octylphenyl ether molecular chain to form a core-shell structure, which improves the dispersion stability of the surfactant in the melt; ammonia treatment introduces -NH2 groups on the particle surface, which form coordination bonds with metal oxides (such as CuO) through chemical reaction, thereby improving the capture efficiency of the slag remover for inclusions; and overall, it improves the dispersibility of the slag remover and the removal rate of inclusions.

[0027] In another technical solution, the altering element is a combination of manganese, titanium, silicon and mixed rare earth elements, wherein the mass ratio of manganese, titanium, silicon and mixed rare earth elements is 3:2:1:1; the mixed rare earth elements are lanthanum and cerium with a mass ratio of 2:1. Manganese powder, titanium powder, silicon powder, and mixed rare earth element powder were pretreated separately and dried in a vacuum environment of 300℃ and -0.09MPa for 1 hour to remove surface moisture and impurities. Then, the treated powders were thoroughly mixed to make granular modifiers with a particle size of 1-3mm to improve their dispersibility in the alloy liquid. The beneficial effects of this technical solution are that by using a combination of manganese, titanium, silicon and rare earth elements in a specific ratio as a modifier, the synergistic effect of multiple elements can more effectively refine the grains and improve the strength, hardness and corrosion resistance of copper alloys. Compared with a single modifier element or a traditional combination of modifier elements, this new combination can reduce the grain size of copper alloys and improve corrosion resistance by more than 20%.

[0028] In another technical solution, in step S5, after heating to 1120-1130℃, oxygen-enriched flame technology is used for flame propagation. The flame propagation gas is a mixture of oxygen and propane, with a volume ratio of oxygen to propane of 5:1. The flame propagation pressure is 0.2-0.3MPa, and the flame propagation time is 1 minute. The beneficial effects of adopting the above technical solution are that oxygen-enriched flaming can not only rapidly increase the temperature of the alloy liquid, but also form a thin oxide film on the surface of the alloy liquid, reducing the loss of volatile elements in the alloy liquid. At the same time, the oxide film can promote the dissolution and diffusion of the modifier, which is an advantage that traditional flaming processes do not have. Through this technology, the loss rate of volatile elements such as zinc in the alloy liquid is reduced by more than 15%.

[0029] <Example 1> This invention provides a novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy, the preparation method of which is as follows: S1. Weigh out copper (Cu 99.9%), zinc (0#Zn), tin (Sn 99.95%), copper-30% iron alloy (Cu-30%Fe alloy, copper-iron alloy copper ingot CuFe5), aluminum (Al 99%), arsenic (As 99%), nickel (Ni 99.9%), and the modifying element, wherein the modifying element is manganese; in this embodiment, the initial amounts of each element are: copper 63.5%, lead 0.08%, aluminum 0.68%, tin 0.13%, nickel 0.08%, iron 0.08%, arsenic 0.12%, Mn 0.07%, with the balance being Zn; S2. The bottom of the induction furnace is lined with loose copper powder or copper shavings, then the smelting materials (copper and copper-30% ferroalloy) are added and covered with charcoal. The temperature is raised to 1100℃ until all the materials are melted. A slag remover is added to filter out the surface slag. The dosage of the slag remover is 4kg for every 1.5 tons of smelting material. The slag remover used is from Hongguang Technology, a pollution-free and high-efficiency flux, which mainly removes oxides and slag after smelting to avoid excessive thickness, which would affect the quality of the final product. S3. Adjust the temperature to 1050℃, add 0#Zn to the material obtained in S2 and quickly press it into the bottom of the furnace. Stir thoroughly after it melts. S4. Add tin and arsenic to the material obtained in S3 and stir thoroughly until homogeneous; S5. Add the modified element, aluminum, and nickel to the alloy liquid obtained in S4, heat to 1120℃, spray, stir, and hold for 3 minutes; take a sample for spectral analysis. If the composition deviates from the target range, adjust by adding pure metal or intermediate alloy (e.g., add copper if Cu is insufficient to reach the target range). In actual use, an appropriate amount of raw material can be weighed according to the target weight percentage. For example, if the target weight percentage of Cu is 62.5-64.0% and the target weight percentage of Fe is ≤0.15%, an appropriate amount of electrolytic copper and Cu-30%Fe intermediate alloy can be weighed first to make the Cu percentage close to 62.5%. In this way, if the percentage of copper is detected to be less than the target range during subsequent composition testing, copper can be added and the composition can be tested again until it meets the target range. This is a conventional technique in the field. For more detailed operation, follow the conventional procedures in the field. S6. Place the material obtained in S5 at 1020℃ and keep it at that temperature for 15 minutes to make the alloy uniform and the impurities float up. Filter out the scum and impurities. S7. Heat the material obtained in S6 to 1080℃, pour it out of the furnace and cast it into ingots. After cooling, it becomes copper alloy raw material.

[0030] <Example 2> Example 2 differs from Example 1 in that the initial amounts of each element are: copper 63.5%, lead 0.05%, aluminum 0.65%, tin 0.12%, nickel 0.01%, iron 0.1%, arsenic 0.14%, Mn 0.07%, with the balance being Zn; Everything else is the same as in Example 1.

[0031] <Example 3> Example 3 differs from Example 1 in that the initial amounts of each element are: copper 64%, lead 0.05%, aluminum 0.65%, tin 0.08%, nickel 0.01%, iron 0.1%, arsenic 0.12%, Mn 0.07%, with the balance being Zn; Everything else is the same as in Example 1.

[0032] <Example 4> Example 4 differs from Example 1 in that the initial amounts of each element are: copper 64.2%, lead 0.06%, aluminum 0.6%, tin 0.1%, nickel 0.01%, iron 0.03%, arsenic 0.15%, Mn 0.07%, with the balance being Zn; Everything else is the same as in Example 1.

[0033] <Example 5> Example 5 differs from Example 1 in that the initial amounts of each element are: copper 64.5%, lead 0.05%, aluminum 0.6%, tin 0.05%, nickel 0.01%, iron 0.06%, arsenic 0.14%, Mn 0.07%, with the balance being Zn; Everything else is the same as in Example 1.

[0034] <Comparative Example 1> Comparative Example 1 is a copper alloy with grade SG-SMS63. The initial amounts of each element in Comparative Example 1 are: copper 62%, lead 0.2%, aluminum 0.68%, tin 0.13%, nickel 0.1%, iron 0.1%, arsenic 0.13%, Mn 0.07%, and the balance is Zn; Everything else is the same as in Example 1.

[0035] <Ingredient Analysis> The composition of the copper alloys prepared in Examples 1-5 and Comparative Example 1 was tested respectively, and the test results are shown in Table 1.

[0036] Table 1. Results of copper alloy composition analysis (wt%) for Examples 1-5 and Comparative Example 1 As can be seen from Table 1, the copper alloy prepared by this invention has a lower lead content than the copper alloy of Comparative Example 1, meets the standards of many countries, and has good application prospects. It should be noted that the lead in the copper alloy is usually introduced from the raw materials and other substances during the processing. Unavoidable impurities are elements that are inevitably added during the elongation process.

[0037] <Corrosion Resistance Test> Test method: The corrosion resistance test was carried out in accordance with the national standard GB / T 10119-2008. The specific results are shown in Table 2.

[0038] Table 2. Results of corrosion resistance tests on the copper alloys prepared in Examples 1-5 and Comparative Example 1. Table 2 shows that the copper alloys prepared in Examples 1-5 have corrosion resistance and dezincification resistance within 100 μm in all directions. The data have been verified to be stable, meeting the requirements of the material dezincification resistance test, and are superior to Comparative Example 1.

[0039] <Metallographic analysis of copper alloys in Examples 1-3 and Comparative Example 1> Metallographic analysis was performed on the copper alloys of Examples 1-3 and Comparative Example 1. Specific results are shown in [the table below]. Figures 1-4 The results showed that the copper alloys in Examples 1-3 all met the corrosion resistance requirements.

[0040] <Mechanical Performance Testing> The mechanical properties of the copper alloys prepared in Examples 1-5 and Comparative Example 1 were measured, and the results are shown in Table 3.

[0041] Table 3. Mechanical property test results of copper alloys prepared in Examples 1-5 and Comparative Example 1. As shown in Table 3, the tensile strength of Examples 1-5 is between 358-376 MPa, and the elongation is between 9.5-10.8, all of which have good mechanical properties and can meet the requirements of industrial applications.

[0042] <Determination of Alloy Qualification Rate in Secondary Annealing Process> 1. Optimization of annealing temperature To achieve stable corrosion resistance and meet the material's dezincification resistance requirements, a secondary annealing treatment is necessary. Annealing, as an important heat treatment process, can effectively improve the microstructure and properties of copper alloys to meet different application requirements. During annealing, the grains inside the copper alloy grow and recrystallize, eliminating work hardening, reducing hardness, and improving plasticity and toughness. Simultaneously, annealing can also eliminate residual stress, improve the alloy's microstructure, and enhance its dezincification resistance.

[0043] 1) Experimental Materials and Methods Experimental materials: copper alloys of Example 1 and Comparative Example 1.

[0044] Experimental equipment: A well-type resistance furnace was used for heating, equipped with a high-precision temperature control system and thermocouples to ensure accurate temperature control. A metallographic microscope was used to observe the tissue structure.

[0045] Experimental Methods: The copper alloys from Example 1 and Comparative Example 1 were used to prepare basin faucets, serving as test and control samples for comparative testing. First, the copper alloy samples were neatly arranged in an iron cage and placed in a pit-type annealing furnace. The furnace was slowly heated to the designed temperature and held for 3 hours, then allowed to cool slowly and naturally. Specific process parameters and metallographic results are shown in Table 4. Table 4. Metallographic analysis results of copper alloys of Example 1 and Comparative Example 1 at different annealing temperatures. 2) Experimental Results Metallographic observation results: The metallographic structure of the samples after different annealing processes was observed by metallographic microscope. The results showed that: when annealed at a lower temperature, the grain size was smaller and a certain number of dislocations and twins were present in the structure; as the annealing temperature increased, the grains gradually grew, the number of dislocations and twins decreased, and the structure became more uniform; when the annealing temperature was too high, the grains grew excessively, which led to a decrease in the performance of the alloy.

[0046] Analysis of the changes in metallographic structure demonstrates that the annealing process has a significant impact on the microstructure and properties of copper alloys. Annealing effectively improves the microstructure and properties of copper alloys, reducing hardness and increasing plasticity and toughness. Annealing temperature and holding time are key factors affecting the annealing effect of copper alloys. Within a certain range, as the annealing temperature increases and the holding time prolongs, the hardness of the copper alloy gradually decreases, and the microstructure becomes more uniform. The copper alloy of this invention, annealed at 592°C, 603°C, and 609°C, showed uniform microstructure distribution in metallographic analysis. In contrast, the comparative alloy only showed uniform microstructure distribution at around 602°C. At 591°C and 608°C, close to the suitable annealing temperatures for the copper alloy of this invention, the microstructure distribution of the comparative alloy was uneven. This indicates that, through formulation optimization, the copper alloy of this invention has a wider range of annealing temperatures. The comparative sample SMS63 exhibited metallographic instability due to differences in component ratios.

[0047] 2. Product qualification rate determination in the secondary annealing process The copper alloy of this invention and the comparative alloy were subjected to secondary annealing. The parameters for the secondary annealing were: annealing temperature 602℃, holding time 3 hours, and furnace cooling. The pass rate of the copper alloy of this invention and the comparative alloy after the secondary annealing process was determined. The results are shown in Table 5. The pass rate was determined by randomly selecting W samples from the corresponding production batches of the copper alloy of this invention and the comparative alloy after the secondary annealing process, performing metallographic analysis on all W samples, and counting the number N samples with uniform microstructure distribution. The pass rate was then calculated as 100% * N / W.

[0048] Table 5. Results of the pass rate determination of copper alloys in Example 1 and Comparative Example 1 during the secondary annealing process. As shown in Table 5, the optimized formula of this invention results in a more stable and uniform metallographic distribution in the copper alloy, thereby increasing the pass rate of the copper alloy in the secondary annealing stage by 100%*(92.5-70.4) / 70.4=31.4%. This significantly improves the pass rate of the copper alloy in the secondary annealing stage, indirectly increasing the production efficiency of the copper alloy in the casting process. This is because if the product fails the secondary annealing stage, it needs to be re-annealed, greatly reducing production efficiency. The copper alloy of this invention, after formula optimization, can greatly improve the pass rate of the secondary annealing stage. This discovery was unintentional during the experiment and has great potential for production application.

[0049] In summary, this invention optimizes the formulation of the original copper alloy with the grade SG-SMS63, resulting in a more stable and uniform metallographic distribution. This significantly improves the pass rate of the copper alloy in the secondary annealing process, increases the production efficiency of casting products, and the prepared copper alloy exhibits excellent corrosion resistance, anti-dezincification properties, and correspondingly improved mechanical properties, demonstrating promising application prospects.

[0050] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy, characterized in that... Its weight percentage composition is as follows: copper 62%-64.5%, lead 0%-0.1%, aluminum 0.55%-0.70%, tin 0.05%-0.15%, nickel 0-0.02%, iron 0%-0.15%, arsenic 0.1%-0.14%, with the balance being Zn and unavoidable impurities, the total of which is ≤0.2%.

2. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 1, characterized in that, Includes the following steps: S1. Weigh out copper, zinc, tin, copper-30% iron alloy, aluminum, arsenic, nickel and the modifying element, wherein the modifying element is at least one of manganese, titanium, silicon and rare earth elements; S2. Place copper and copper-30% iron alloy at the bottom of the induction furnace, cover with charcoal, heat to 1050~1150℃ until all materials are melted, add slag remover, and filter out the surface slag. S3. Adjust the temperature to 1030~1080℃, add zinc to the material obtained in S2 and quickly press it into the bottom of the furnace. Stir thoroughly after it melts. S4. Add tin and arsenic to the material obtained in S3, stir thoroughly until homogeneous, then add aluminum and nickel, and stir thoroughly until homogeneous. S5. Add the modifying element to the alloy liquid obtained in S4, heat to 1080~1150℃, spray fire, stir and keep warm for 2-3 minutes. S6. Place the material obtained in S5 at 1000~1050℃ and keep it at that temperature for 10-20 minutes to make the alloy uniform and the impurities float up. Filter out the scum and impurities. S7. Heat the material obtained in S6 to 1050~1100℃, remove it from the furnace and cast it into ingots. After cooling, it becomes a copper alloy.

3. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 1, characterized in that, Step S2 specifically involves: alternately spreading copper and copper-30% ferroalloy on the bottom of an induction furnace to form a 3-5 layer composite structure, with each layer controlled to a thickness of 5-8 cm. Each layer of copper / copper-30% ferroalloy is covered with a 1.5-2.5 cm thick layer of modified charcoal, which is made from natural charcoal soaked in a 5% boric acid solution and then dried. A slag-removing agent is added, and the temperature is then raised to 1100-1120℃ and held for 15-20 minutes. The slag-removing agent is a CaO-Al2O3-MgO ternary system, composed of 45% CaO, 35% Al2O3, and 20% MgO. The amount of CaO-Al2O3-MgO added is 0.4-0.6% of the total weight of the copper and copper-30% ferroalloy.

4. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 3, characterized in that, The preparation of the modified charcoal layer includes the following steps: A1. Crush natural oak charcoal to a particle size of 2-5mm, place it in a 5% boric acid solution at 55-65℃, and perform ultrasonic-assisted soaking at a liquid-solid ratio of 3:

1. The ultrasonic conditions are: ultrasonic frequency 40kHz, ultrasonic power 200W, and treatment for 30-45 minutes. A2. The natural oak charcoal soaked in A1 was dried by vacuum drying to obtain modified charcoal. The vacuum drying conditions were: vacuum degree -0.1MPa, temperature 120±5℃, drying time 2 hours. A3. After vacuum drying in A2, a 0.3-0.5% nano-SiO2 dispersion is uniformly sprayed onto the surface of the charcoal to form a composite coating with a thickness of 1-2 μm, thus obtaining the modified charcoal layer; wherein, the nano-SiO2 dispersion has a particle size of 20-50 nm and the dispersion medium is ethanol.

5. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 3, characterized in that, The preparation of the CaO-Al2O3-MgO ternary system is specifically as follows: B1. Raw material pretreatment: CaO, Al2O3 and MgO are ground to a particle size ≤5μm and placed in a vacuum drying oven at 150℃ for 4 hours to obtain pretreated raw materials; B2. Nanocomposite modification: The pretreated raw materials are mixed in a ratio of 45:35:20, and 2% of nano TiO2 and 1% of graphene nanosheets are added by mass. The composite powder is formed by high-energy ball milling. The conditions for high-energy ball milling are: rotation speed 800 rpm and time 2 hours.

6. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 5, characterized in that, It also includes step B3, which specifically involves: the sludge remover further containing 0.5% of a surfactant by mass, which is then processed into spherical particles with a particle size of 1-3 mm by spray granulation, wherein the surfactant is polyethylene glycol octylphenyl ether.

7. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 6, characterized in that, The slag remover also contains 0.5% surfactant by mass, and the specific preparation method for producing spherical particles with a particle size of 1-3 mm by spray granulation is as follows: C1. Surfactant pretreatment: Polyethylene glycol octylphenyl ether and 15% by mass of nano-SiO2 are ultrasonically dispersed in a 50°C water bath. The ultrasonic conditions are: frequency 40kHz, power 300W, ultrasonic for 30 minutes to form a stable mixed solution, which is the pretreated surfactant. C2. Spray granulation: The pretreated surfactant is sprayed onto the composite powder in B2 in a pressure spray drying tower, and narrow-distribution particles with a particle size of 1-3 mm are obtained by fluidized bed classification and screening; then ammonia gas is immediately introduced to form an aminated layer on the particle surface; wherein, the ammonia gas flow rate is 5 L / min. The conditions for processing in the pressure spray drying tower are as follows: compressed air pressure 0.6MPa, feed rate 50mL / min, drying tower inlet air temperature 220±5℃, and outlet air temperature 110±5℃.

8. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 2, characterized in that, The altering elements are selected from a combination of manganese, titanium, silicon and mixed rare earth elements, wherein the mass ratio of manganese, titanium, silicon and mixed rare earth elements is 3:2:1:1; the mixed rare earth elements are lanthanum and cerium with a mass ratio of 2:

1. Manganese powder, titanium powder, silicon powder, and mixed rare earth element powder were pretreated separately and dried in a vacuum environment of 300℃ and -0.09MPa for 1 hour to remove surface moisture and impurities. Then, the treated powders were thoroughly mixed to make granular modifiers with a particle size of 1-3mm to improve their dispersibility in the alloy liquid.

9. The preparation method of the novel corrosion-resistant, dezincification-resistant, environmentally friendly, lead-free copper alloy as described in claim 8, characterized in that, In step S5, after heating to 1120-1130℃, oxygen-enriched flaming technology is used for flaming. The flaming gas is a mixture of oxygen and propane, with a volume ratio of oxygen to propane of 5:

1. The flaming pressure is 0.2-0.3MPa, and the flaming time is 1 minute.

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