Anti-zinc-falling environment-friendly copper alloy for faucet and preparation method thereof

Abstract

This invention provides an anti-zincification environmentally friendly copper alloy for faucets and its preparation method. The anti-zincification environmentally friendly copper alloy comprises the following elements by mass percentage: Cu 63-64%; Pb 0.1-0.19%; Fe 0.08-0.1%; Sn 0.08-0.12%; Al 0.5-0.55%; Ni 0.05-0.09%; Mn ≤0.02%; Bi ≤0.02%; Si ≤0.01%; As 0.02-0.04%; Sb 0.02-0.05%; Cr ≤0.002%; B 0.001-0.002%; Ti The content is ≤0.003%, with the balance being Zn and unavoidable impurities; the preparation method of the anti-dezinc environmentally friendly copper alloy includes the following steps: weighing the raw materials according to the proportion, adding a refining agent, and removing iron; putting the weighed raw materials into an electric melting furnace and melting them at 1050℃-1150℃, adding a slag remover during the melting process and implementing at least one high-temperature flame treatment; adding a slag remover again after the flame treatment, letting it stand, and then casting it into shape; the anti-dezinc environmentally friendly copper alloy for faucets of the present invention, while maintaining the lead content in accordance with environmental protection standards, utilizes the synergistic effect of multiple elements such as Pb, As, Sb, and B to improve the anti-dezinc performance.

Description

Technical Field

[0001] This invention belongs to the technical field of copper alloy materials, and in particular relates to an anti-dezincification environmentally friendly copper alloy for faucets and its preparation method. Background Technology

[0002] Brass is widely used in the manufacture of water-contact components such as faucets and valves due to its excellent mechanical properties, machinability, and corrosion resistance. However, brass suffers from selective dezincification corrosion during use, where zinc, the component with the more negative electrode potential, preferentially dissolves, leaving a porous copper layer on the material surface. This leads to a decrease in component strength and a shortened service life.

[0003] To prevent dezincification in brass, the metallurgical industry typically employs the addition of trace alloying elements. Studies have shown that adding elements such as As, B, Sb, Sn, Al, and rare earth elements to copper alloys can inhibit dezincification corrosion to varying degrees, with As and B showing the best effects. The amount of As added is usually controlled within the range of 0.02%-0.06% by mass; excessive addition increases the susceptibility of brass to stress corrosion cracking. The amount of B added is 0.002%-0.01% by mass, which can significantly improve the dezincification resistance of brass. However, the solubility of B in brass is limited, and its refining effect no longer increases after the amount added exceeds 0.02%.

[0004] In recent years, with the EU's increasing environmental requirements for faucet materials, CC771S grade copper alloy has become the preferred material for faucet production. The chemical composition requirements for CC771S are: Cu 62-65%, Fe≤0.2%, Mn≤0.1%, Ni≤0.2%, Pb≤0.2%, Sn≤0.3%, As 0.02-0.04%, Sb 0.02-0.05%, Al 0.45-0.7%, Zn as balance, and other individual impurity elements ≤0.02%. This material must simultaneously meet multiple requirements, including: lead content below 0.2%, lead value in immersion water ≤0.005mg / L (GB / T17219-1998 standard), passing the anti-zincification test (AS2345-2006 standard), good casting fluidity, impurity-free fine polishing and electroplating, and controllable cost.

[0005] Currently, while most domestically produced copper alloys meet the composition requirements of CC771S, they fail the dezincification resistance test, necessitating an additional annealing process to satisfy the dezincification resistance requirement. Annealing not only increases the cost by approximately 1400 yuan per ton but also extends the production cycle and reduces production efficiency.

[0006] Therefore, there is a need for a copper alloy material that can meet the composition requirements and anti-zinc desulfurization properties of CC771S without annealing. Summary of the Invention

[0007] The first objective of this invention is to provide a dezincification-resistant and environmentally friendly copper alloy for use in faucets, and the second objective of this invention is to provide a method for preparing the aforementioned dezincification-resistant and environmentally friendly copper alloy for use in faucets.

[0008] To achieve the first objective of this invention, the following technical solution is adopted: A dezincification-resistant and environmentally friendly copper alloy for faucets, comprising the following elements by weight percentage: Cu 63-64%; Pb 0.1-0.19%; Fe 0.08-0.1%; Sn 0.08-0.12%; Al 0.5-0.55%; Ni 0.05-0.09%; Mn ≤0.02%; Bi ≤0.02%; Si ≤0.01%; As 0.02-0.04%; Sb 0.02-0.05%; Cr ≤0.002%; B 0.001-0.002%; Ti ≤0.003%, with the balance being Zn and unavoidable impurities.

[0009] In this invention: Cu (copper) serves as the matrix element, with its content controlled between 63-64%. The Cu content directly affects the alloy's microstructure and corrosion resistance. Too low a Cu content reduces its resistance to dezincification, while too high a Cu content increases material costs. Controlling the Cu content within the range of 63-64% ensures the alloy has a sufficient proportion to maintain its resistance to dezincification while also maintaining economic efficiency.

[0010] The lead (Pb) content is 0.1-0.19%. This invention, while ensuring that the lead leaching amount meets the GB / T 17219-1998 standard (lead value in immersion water ≤ 0.005 mg / L), retains trace amounts of lead to improve the alloy's machinability and prevent cracking of the casting during cooling. An appropriate amount of lead acts as a lubricant at grain boundaries, reducing the tendency for hot cracking.

[0011] The Fe (iron) content is 0.08-0.1%. Iron has low solubility in solid solutions, and undissolved Fe precipitates as fine iron-rich phases, which can refine the grain structure of brass, improve mechanical properties, and not affect the surface polishing quality. When the Fe content is too high, it will agglomerate at the grain boundaries, reducing the plasticity and corrosion resistance of the material.

[0012] The Sn (tin) content is 0.08-0.12%. Tin is one of the effective elements for improving the dezincification resistance of brass. During corrosion, tin forms a SnO2 protective film on the surface and can be enriched at grain boundaries, inhibiting the selective dissolution of zinc. In addition, an appropriate amount of tin can reduce the casting shrinkage tendency of the alloy, but excessive addition will increase material costs and reduce plasticity.

[0013] The Al (aluminum) content is 0.5-0.55%. Aluminum can improve the fluidity of copper alloy melts, enhance casting performance, and strengthen the alloy's resistance to dezincification. Aluminum has a high Zn equivalent coefficient in brass; even a small amount can significantly affect the microstructure, but excessive addition will promote the formation of brittle phases and reduce the material's plasticity and toughness.

[0014] The nickel content is 0.05-0.09%. Nickel can enhance the dezincification resistance of copper alloys, and in copper alloys such as aluminum bronze, the addition of nickel can improve corrosion resistance. The introduction of trace amounts of nickel has little impact on cost, but has a synergistic effect on dezincification resistance.

[0015] The manganese (Mn) content should be controlled below 0.02%. Manganese can prevent cracks and shrinkage defects in faucet castings after casting and cooling. Manganese has a good solid solution strengthening effect in solid solutions, but if the content is too high, it will precipitate as a manganese-rich embrittlement phase, reducing the toughness of the material.

[0016] The bismuth content should be controlled below 0.02%. The addition of bismuth can prevent cracks from forming in the casting during the casting cooling process. However, since bismuth has low solubility in copper, excessive addition will form a low-melting-point eutectic phase, which will have an adverse effect on hot working performance. Therefore, its upper limit needs to be controlled.

[0017] The silicon (Si) content should be controlled below 0.01%. Silicon has a high Zn equivalent coefficient in brass, and even a trace amount can promote the formation of brittle phases, making the material too hard during machining and aggravating tool wear. Therefore, it is necessary to control its upper limit.

[0018] The arsenic content is 0.02-0.04%. Arsenic is one of the most effective elements in inhibiting zinc removal from brass. The mechanisms of action of arsenic include: forming a Cu-As-Zn protective layer at grain boundaries to hinder preferential zinc dissolution, or forming double-vacancy-As pairs to hinder double-vacancy migration, and it can also increase the efficiency of Cu removal. 2+ The overpotential of the reduction reaction inhibits the redeposition of copper. An addition of 0.02%-0.04% can effectively inhibit dezincification without increasing susceptibility to stress corrosion cracking.

[0019] The Sb (antimony) content is 0.02-0.05%. Antimony can enhance the tensile strength of the alloy and reduce casting shrinkage. The segregation of antimony at grain boundaries can inhibit the diffusion channels of zinc, and when combined with arsenic, it can further improve the anti-zincification effect. However, excessive Sb content will reduce the plasticity and toughness of the material.

[0020] The chromium (Cr) content should be controlled below 0.002%. Chromium helps prevent impurities and defects from appearing during product surface polishing. Chromium has limited solubility in copper; excessive addition will form coarse, chromium-rich phases, affecting surface quality. Therefore, the amount of chromium used must be strictly controlled.

[0021] The boron (B) content is 0.001-0.002%. Boron refines the grain structure of brass, making the grain distribution more uniform and thus improving the material's mechanical properties. Furthermore, boron can occupy or diffuse into double vacancies, slowing their migration and inhibiting the selective dissolution channels of zinc, thereby enhancing brass's resistance to dezincification. A boron addition of 0.001%-0.002% can achieve a significant synergistic effect of grain refinement and resistance to dezincification.

[0022] The titanium (Ti) content is controlled below 0.003%. Titanium helps prevent impurities from appearing during faucet polishing, and it also refines the casting microstructure in copper alloys. Studies have shown that Ti-containing modification treatment can refine the casting microstructure of leaded brass, transforming coarse plate-like structures into fine equiaxed grain structures.

[0023] Preferably, the mass percentage of Cu is 63.2-63.8%, and the mass percentage of Pb is 0.12-0.17%. With the copper and lead contents within this range, the alloy ratio will be more reasonable, and the machinability and anti-dezincification properties will achieve a better balance.

[0024] Preferably, the mass percentage of B is 0.0012-0.0018%, the mass percentage of As is 0.025-0.035%, and the mass percentage of Sb is 0.025-0.045%. Within this range, the synergistic anti-dezincification effect of B, As, and Sb is optimal, while avoiding stress corrosion sensitivity caused by excessive As.

[0025] Preferably, the sum of the mass percentages of Fe and Sn is 0.16-0.22%. Fe and Sn have a synergistic effect in grain refinement and anti-dezincification. Controlling the sum of the two within this range can balance the grain refinement effect and anti-dezincification performance, and will not affect the plasticity and polishing quality of the material due to excessive addition.

[0026] To achieve the second objective of this invention, the following technical solution is adopted: A method for preparing the anti-zinc dezincification environmentally friendly copper alloy for faucets includes the following steps: S1: Weigh out 65 brass scrap, 62 brass scrap, tin copper, cupronickel, lead-free brass, copper, Zn, Al, As, Sb, and Pb as raw materials according to the formula, add a refining agent, and remove iron. S2: The weighed raw materials are put into an electric melting furnace and melted at 1050℃-1150℃. During the melting process, a slag remover is added and at least one high-temperature blasting treatment is carried out. S3: After flame treatment, add slag remover again, let stand, and then cast into shape.

[0027] In step S1 of the preparation method of the present invention, the iron removal process is carried out by an iron removal machine. Iron is a common impurity element in copper alloys. Fe has limited solubility in solid solution. Undissolved Fe phase may be exposed on the surface during subsequent polishing, forming polishing impurity points and affecting the surface quality of the faucet product. Therefore, removing iron impurities from the raw materials by an iron removal machine before smelting can ensure the surface quality of the product.

[0028] Preferably, in S1, the addition amounts of each raw material, by mass percentage, are: 37.4-37.5% 65 brass scrap, 7% 62 brass scrap, 0.7% tin copper, 0.2% cupronickel, 32% lead-free brass, 14% copper, 8% Zn, 0.56% Al, 0.02% As, 0.02% Sb, and 0.1% Pb.

[0029] Preferably, in step S2, the order of feeding raw materials into the furnace is as follows: 65 brass scrap, 62 brass scrap, lead-free bran, cupronickel, copper, tin-copper, Zn, Al, As, Sb, Pb; wherein, after the 65 brass scrap and 62 brass scrap are fed into the furnace and slag is removed, lead-free bran, cupronickel, and the first slag remover are added, and after slag removal again, the remaining raw materials are added for high-temperature smelting.

[0030] In step S2 of the preparation method of the present invention, the principle of the order of feeding raw materials into the furnace is as follows: 65 brass and 62 brass scraps are used as the main copper and zinc sources, respectively, and are melted first to form a basic copper-zinc melt. At this time, a refining agent is added so that the refining agent can be evenly dispersed in the melt. After removing the surface oxides by slag removal, lead-free bran and cupronickel and the first slag remover are added. Lead-free bran is a low-grade copper-zinc waste with a low melting temperature, which can be melted quickly in the basic melt. Cupronickel is used as a nickel source. Adding it at this stage can make the nickel fully dissolve in the copper matrix. The role of the slag remover is to adsorb oxide inclusions and gases in the melt, so that the slag is separated from the molten metal and is easy to remove.

[0031] Preferably, the high-temperature flame treatment is performed in two stages: the first flame treatment is carried out during the smelting process, and after flame treatment, the sample is left to stand and the composition and polishing effect are analyzed; the second flame treatment is carried out after the composition analysis meets the standards, and after flame treatment, the sample is left to stand again before casting.

[0032] The two-stage flame treatment process takes into account the precision of composition control. After the first flame treatment, a sample is taken for composition analysis. If the composition deviates from the target range, it can be adjusted by adding the corresponding elements. The polishing effect analysis is used to determine the degree of removal of inclusions in the melt. If the polishing effect is not ideal, a second flame treatment can be performed.

[0033] Preferably, the refining agent is a boron refining agent, and the slag remover is a glassy slag remover.

[0034] In this invention, the addition of boron refining agent can form fine particles during the melting process, which serve as a heterogeneous nucleation substrate, promote grain refinement, make the grain size in the casting structure more uniform, and reduce columnar and dendritic segregation.

[0035] In this invention, the main component of the glassy slag remover is a silicate substance, which has a lower density than the copper alloy melt and floats on the surface of the melt. It can adsorb oxide inclusions such as Al2O3 and ZnO in the melt, as well as gases such as hydrogen dissolved in the melt, thus playing a refining and purifying role. The glassy slag remover does not chemically react with the copper alloy melt and does not change the composition of the alloy.

[0036] Preferably, in step S3, after the flame treatment, a slag remover is added again, the settling time is 5 minutes, and then the mixture is cast into shape.

[0037] Adding a slag remover again after the flame treatment can further adsorb inclusions exposed during the flame treatment. The preferred settling time is 5 minutes to allow inclusions and gases in the melt to float to the surface, ensuring the purity of the melt.

[0038] The preparation principle of the anti-zinc desulfurization environmentally friendly copper alloy for faucets of the present invention is as follows: The order of adding elements to the furnace during the smelting process follows the principle of "high melting point first, then low melting point; major elements first, then trace elements." Specifically: 65 and 62 brass scraps, serving as the primary alloying source, have high melting points. Their early melting facilitates the formation of a stable molten pool, providing the thermal basis for the rapid dissolution of subsequent low-melting-point raw materials. Lead-free bran, with its high zinc content, melts rapidly in the base melt, reducing zinc loss. Trace elements such as Al, As, Sb, and Pb are added later in the smelting process, allowing for precise control of their final content and preventing loss and compositional deviations caused by prolonged high-temperature smelting.

[0039] The two additions of the slag remover have different functions: the first addition is during the smelting process, which mainly removes oxide inclusions brought in by the raw materials and slag generated during the smelting process; the second addition is after the flame treatment, which mainly removes inclusions that float out from the inside of the melt during the flame treatment, thus playing a role in refining and purifying.

[0040] High-temperature flame treatment purifies the melt through both thermodynamic and kinetic effects. Under high-temperature conditions, the solubility of dissolved gases in the melt decreases, allowing the gases to precipitate. Simultaneously, the high temperature reduces the melt viscosity, which is beneficial for the collision, aggregation, and flotation of inclusions. The surface disturbance of the melt caused by flame treatment also helps to break the interfacial tension between inclusions and the melt, promoting the inclusions to enter the slag remover layer and be removed.

[0041] The addition of grain refiners is completed early in the melting process, ensuring that the refiners have sufficient time to disperse uniformly in the melt, forming a large number of heterogeneous nucleation sites. This provides more nucleation sites during solidification, resulting in a fine equiaxed grain structure. A fine grain structure not only improves mechanical properties but also reduces dendritic segregation and shrinkage cavities, thus increasing the density of the casting.

[0042] The beneficial effects of this invention are: The anti-zincification environmentally friendly copper alloy for faucets of the present invention can meet the anti-zincification test without annealing during the preparation process, saving production costs and production cycle.

[0043] The present invention provides an environmentally friendly copper alloy for faucets that resists dezincification. While maintaining the lead content in compliance with environmental standards, it utilizes the synergistic effect of multiple elements such as Pb, As, Sb, and B to significantly improve the dezincification resistance while ensuring that the lead leaching amount meets the standards. The average dezincification depth in the dezincification test is ≤45.5μm.

[0044] The addition of trace elements such as B, Ti, and Cr to the anti-zinc desulfurization environmentally friendly copper alloy for faucets of this invention refines the alloy grains, improves the uniformity of the structure, and ensures that the polished surface of the product is free of impurities and defects, increasing the yield rate from 56% of traditional materials to over 98%.

[0045] The preparation method of the anti-zinc dezincification environmentally friendly copper alloy for faucets of the present invention effectively controls the precision of alloy composition and the purity of melt by optimizing the order of feeding each raw material into the furnace, adding slag remover twice and high-temperature blasting treatment, thus ensuring the stability and consistency of product quality. Attached Figure Description

[0046] Figure 1 The flowability test results of the anti-zinc dezincification environmentally friendly copper alloy for faucets in Embodiment 1 of the present invention. Figure 1 ; Figure 2 Flowability test of the anti-zincification environmentally friendly copper alloy for faucets in Embodiment 1 of the present invention. Figure 2 ; Figure 3 This is a comparative diagram showing the shrinkage test results of the anti-zincification environmentally friendly copper alloy for faucets according to the present invention. Figure 3 (a) is a diagram showing the shrinkage test results of Comparative Example 4; Figure 3 (b) is a diagram showing the shrinkage test results of Example 1; Figure 4 Metallographic features of the anti-zinc desulfurization environmentally friendly copper alloy for faucets, as described in Embodiment 1 of the present invention. Figure 1 ; Figure 5 Metallographic features of the anti-zinc desulfurization environmentally friendly copper alloy for faucets, as described in Embodiment 1 of the present invention. Figure 2 ; Figure 6 Metallographic features of the anti-zinc desulfurization environmentally friendly copper alloy for faucets, as described in Embodiment 1 of the present invention. Figure 3 . Detailed Implementation

[0047] The invention can be further understood through the specific embodiments given below, but they are not intended to limit the invention. Example 1

[0048] This embodiment 1 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. By mass percentage, the dezincification-resistant and environmentally friendly copper alloy comprises the following elements: Cu 63.5%, Pb 0.15%, Fe 0.09%, Sn 0.10%, Al 0.53%, Ni 0.07%, Mn 0.01%, Bi 0.01%, Si 0.005%, As 0.03%, Sb 0.035%, Cr 0.001%, B 0.0015%, Ti 0.002%, balance Zn and unavoidable impurities.

[0049] The preparation method of the anti-zinc dezincification environmentally friendly copper alloy for faucets in this embodiment 1 includes the following steps: S1: The raw materials are prepared according to the electric melting furnace loading capacity of 2300kg: 37.4% (860kg) of 65 brass scrap, 7% (161kg) of 62 brass scrap, 0.7% (16.1kg) of tin copper, 0.2% (4.6kg) of cupronickel, 32% (736kg) of lead-free bran, 14% (322kg) of copper, 8% (184kg) of Zn, 0.56% (12.88kg) of Al, 0.02% (0.46kg) of As, 0.02% (0.46kg) of Sb, and 0.1% (2.3kg) of Pb, with 0.6kg of boron refining agent added. The raw materials are treated with an iron removal machine to remove iron. S2: Add 860 kg of 65 brass, 161 kg of 62 brass, and 0.6 kg of boron refining agent to the furnace for smelting, and remove the slag. Then add 736 kg of lead-free bran, 4.6 kg of cupronickel, and 5 kg of the first slag remover. Adjust the electric furnace power to 70%, add materials while stirring, remove the slag, and then add 322 kg of copper, 184 kg of Zn, 12.88 kg of Al, 0.46 kg of As, 0.46 kg of Sb, and 2.3 kg of Pb. Adjust the electric furnace power to 95% and carry out high-temperature smelting at 1100℃. S3: After 15 minutes, add 5 kg of the second slag remover, stir evenly, remove the slag, and then perform a high-temperature blow-dry treatment at 1150℃. After blow-drying, reduce the electric furnace power and maintain the temperature. Let the copper liquid stand for 5 minutes, take samples for composition analysis and polishing effect analysis. After the composition meets the standards, adjust the electric furnace power to 90% and perform a second high-temperature blow-dry treatment. After blow-drying, add the slag remover again, let stand for 5 minutes, and then cast to obtain copper ingots. Example 2

[0050] This embodiment 2 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between this embodiment 2 and embodiment 1 is that the mass percentage of certain elements in the dezincification-resistant and environmentally friendly copper alloy for faucets in this embodiment 2 is as follows: The mass percentage of Cu is 63.2%, the mass percentage of Pb is 0.12%, the mass percentage of B is 0.0012%, the mass percentage of As is 0.025%, and the mass percentage of Sb is 0.025%.

[0051] The other components and preparation methods are the same as in Example 1, and will not be repeated here. Example 3

[0052] This embodiment 3 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between this embodiment 3 and embodiment 1 is that the mass percentage of certain elements in the dezincification-resistant and environmentally friendly copper alloy for faucets in this embodiment 3 is as follows: The mass percentage of Cu is 63.8%, the mass percentage of Pb is 0.17%, the mass percentage of B is 0.0018%, the mass percentage of As is 0.035%, and the mass percentage of Sb is 0.045%.

[0053] The other components and preparation methods are the same as in Example 1, and will not be repeated here. Example 4

[0054] This embodiment 4 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between this embodiment 4 and embodiment 1 is that the mass percentage of certain elements in the dezincification-resistant and environmentally friendly copper alloy for faucets in this embodiment 4 is as follows: The mass percentage of Fe is 0.08%, the mass percentage of Sn is 0.08%, and the sum of the mass percentages of Fe and Sn is 0.16%.

[0055] The other components and preparation methods are the same as in Example 1, and will not be repeated here. Example 5

[0056] This embodiment 5 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between this embodiment 5 and embodiment 1 is that the mass percentage of certain elements in the dezincification-resistant and environmentally friendly copper alloy for faucets in this embodiment 5 is as follows: The mass percentage of Fe is 0.10%, the mass percentage of Sn is 0.12%, and the sum of the mass percentages of Fe and Sn is 0.22%.

[0057] The other components and preparation methods are the same as in Example 1, and will not be repeated here. Example 6

[0058] This embodiment 6 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between this embodiment 6 and embodiment 1 is that the melting temperature in the preparation method of the dezincification-resistant and environmentally friendly copper alloy for faucets in this embodiment 6 is 1050℃.

[0059] The other components and preparation methods are the same as in Example 1, and will not be repeated here. Example 7

[0060] This embodiment 7 provides an anti-dezinc environmentally friendly copper alloy for faucets. The difference between this embodiment 7 and embodiment 1 is that the melting temperature in the preparation method of the anti-dezinc environmentally friendly copper alloy for faucets in this embodiment 7 is 1150℃.

[0061] The other components and preparation methods are the same as in Example 1, and will not be repeated here. Example 8

[0062] This embodiment 8 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between this embodiment 8 and embodiment 1 is that in the preparation method of the dezincification-resistant and environmentally friendly copper alloy for faucets in embodiment 8, the raw material ratio in step S1 is as follows: 65 brass scrap 37.5%, 62 brass scrap 7%, tin copper 0.7%, cupronickel 0.2%, lead-free brass 32%, copper 14%, Zn 8%, Al 0.56%, As 0.02%, Sb 0.02%, Pb 0.1%.

[0063] Other preparation methods are the same as in Example 1, and will not be repeated here.

[0064] Comparative Example 1 Comparative Example 1 provides an anti-dezincification environmentally friendly copper alloy for faucets. The difference between Comparative Example 1 and Example 1 is that the anti-dezincification environmentally friendly copper alloy for faucets in Comparative Example 1 does not contain element B.

[0065] The other components and preparation methods are the same as in Example 1, and will not be repeated here.

[0066] Comparative Example 2 Comparative Example 2 provides an anti-dezincification environmentally friendly copper alloy for faucets. The difference between Comparative Example 2 and Example 1 is that the anti-dezincification environmentally friendly copper alloy for faucets in Comparative Example 2 does not contain As.

[0067] The other components and preparation methods are the same as in Example 1, and will not be repeated here.

[0068] Comparative Example 3 Comparative Example 3 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between Comparative Example 3 and Example 1 is that the Pb content in the dezincification-resistant and environmentally friendly copper alloy for faucets in Comparative Example 3 is 0.25%.

[0069] The other components and preparation methods are the same as in Example 1, and will not be repeated here.

[0070] Comparative Example 4 Comparative Example 4 provides a dezincification-resistant and environmentally friendly copper alloy for faucets. The difference between Comparative Example 4 and Example 1 is that the preparation process of the dezincification-resistant and environmentally friendly copper alloy for faucets in Comparative Example 4 does not involve high-temperature flame treatment.

[0071] The other components and preparation methods are the same as in Example 1, and will not be repeated here.

[0072] Test case The anti-zinc desulfurization environmentally friendly copper alloys for faucets in Examples 1-8 and Comparative Examples 1-4 were subjected to performance tests. The tests included anti-zinc desulfurization test, fluidity test, shrinkage test, metallographic structure observation, polished surface quality evaluation, and lead leaching test. The methods for each test were as follows: Zinc removal resistance test: The test was conducted in accordance with BS EN ISO 6509-1:2014. The mounted and ground sample was immersed in a copper chloride test solution at 75°C for 24 hours. After being removed and dried, the sample was mounted, ground, and polished perpendicular to the test surface. The zinc removal depth of the test surface was observed and measured under a metallographic microscope, and the average value was taken from 5 locations.

[0073] Flowability test: A spiral-shaped flowability sample is used for testing. The copper alloy melt is poured into a spiral sand mold at the same temperature (1100℃), and the length of the spiral sample is measured after solidification. The longer the spiral length, the better the flowability of the alloy melt.

[0074] Shrinkage test: A ring-shaped shrinkage specimen is used for testing. A standard ring-shaped specimen is cast, and its shrinkage rate after solidification is measured. The smaller the shrinkage rate, the better the alloy's resistance to shrinkage.

[0075] Metallographic observation: After mounting, grinding and polishing the sample, it was etched with ferric chloride hydrochloric acid solution, observed under a metallographic microscope and photographed (200x). The average grain size was evaluated according to YS / T 347-2004 standard.

[0076] Polished surface quality evaluation: After the casting sample is polished under the same conditions, observe the surface under a magnifying glass to see if there are any defects such as impurities or pits. The surface quality is divided into excellent (no defects), good (a few minor defects), and poor (obvious defects).

[0077] Lead leaching test: Performed in accordance with GB / T 17219-1998 standard. After immersing the sample under specified conditions, the lead content in the immersion solution is determined by atomic absorption spectrometry.

[0078] The test results of the anti-zinc dezincification environmentally friendly copper alloy samples for faucets in Examples 1-8 and Comparative Examples 1-4 are shown in Table 1:

[0079] The results in Table 1 show that: The average dezincification depth of Examples 1-8 was 37.8-45.5 μm, and no annealing treatment was required. Among them, Example 3 exhibited the best resistance to dezincification. Figures 4 to 6 As shown, the zinc removal depth test values ​​at the five locations in Example 1 were 42.6 μm, 60.8 μm, 30.6 μm, 50.5 μm and 48.0 μm, respectively, with an average zinc removal depth of 45.5 μm.

[0080] Figures 4 to 6 Metallographic image of Example 1 (200x magnification). Reference Figures 4 to 6 It can be seen that the alloy in Example 1 has fine and uniform grains, with a grain size of 9.0 grade, clear grain boundaries, and no obvious dendrite segregation or shrinkage defects. Figure 1 and Figure 2 The image shows the flowability test results of Example 1. The spiral sample is fully filled and has a clear outline. The spiral length is measured to be 385 mm, indicating that the alloy melt has good flowability. Figure 3 (b) is a shrinkage test result diagram of Example 1, in which the annular sample has a complete outline and a smooth surface, and the shrinkage rate is 1.6%; the shrinkage test result diagram of Comparative Example 4 is as follows. Figure 3 As shown in (a), the surface of the annular sample has obvious shrinkage depressions and shrinkage cavities, with a shrinkage rate of 2.4%.

[0081] The average dezincification depth of Comparative Example 1 (without B) was 78.6 μm, which was 33.1 μm higher than that of Example 1. The grain size was only grade 7.0, and the microstructure was obviously coarse. This indicates that the addition of B has a significant contribution to refining the grain and improving the dezincification resistance. B enhances the dezincification resistance of the alloy through a dual mechanism of refining the grain and inhibiting the migration of double vacancies.

[0082] The average dezincification depth of Comparative Example 2 (without As) was 72.5 μm, which was higher than that of all other examples, indicating that As is one of the key elements in the dezincification resistance of the present invention. As inhibits dezincification through a dual mechanism of forming a protective layer at the grain boundary and inhibiting the Cu²⁺ reduction reaction.

[0083] Comparative Example 3 (Pb content 0.25%) had an average dezincification depth of 52.8 μm, lower than some examples, but its lead leaching was 0.008 mg / L, exceeding the limit of 0.005 mg / L required by GB / T 17219-1998. This indicates that the Pb content needs to be controlled within the range of this invention (0.1-0.19%) to simultaneously meet processing performance and environmental protection requirements.

[0084] Comparative Example 4 (without high-temperature flame treatment) had an average dezincification depth of 86.3 μm and a poor polished surface quality rating. Figure 3 (a) and Figure 3 The comparison in (b) shows that the shrinkage rate of the casting is significantly increased (2.4%) without flame blasting, and obvious shrinkage defects are present on the surface. This indicates that high-temperature flame blasting plays an irreplaceable role in removing inclusions from the melt and improving the purity of the alloy. Without flame blasting, oxides and gases in the melt cannot be effectively removed, resulting in inclusions and porosity inside the casting, which reduces the resistance to dezincification and deteriorates the surface polishing quality.

[0085] The fluidity test results of Example 1 (spiral length 385 mm) were better than those of Comparative Example 4 (340 mm), indicating that the effective fluidity of the melt was improved after high-temperature flame treatment to remove inclusions. The shrinkage rate of Example 1 (1.6%) was lower than that of Comparative Example 4 (2.4%), indicating that the synergistic addition of multiple elements such as B, As, and Sb effectively suppressed casting shrinkage.

[0086] The above description is merely an embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A dezincification-resistant and environmentally friendly copper alloy for faucets, characterized in that, The dezincification-resistant environmentally friendly copper alloy comprises the following elements by weight percentage: Cu 63-64%; Pb 0.1-0.19%; Fe 0.08-0.1%; Sn 0.08-0.12%; Al 0.5-0.55%; Ni 0.05-0.09%; Mn ≤0.02%; Bi ≤0.02%; Si ≤0.01%; As 0.02-0.04%; Sb 0.02-0.05%; Cr ≤0.002%; B 0.001-0.002%; Ti ≤0.003%, with the balance being Zn and unavoidable impurities.

2. The anti-zinc dezincification environmentally friendly copper alloy for faucets according to claim 1, characterized in that, The mass percentage of Cu is 63.2-63.8%, and the mass percentage of Pb is 0.12-0.17%.

3. The anti-zinc dezincification environmentally friendly copper alloy for faucets according to claim 1, characterized in that, The mass percentage of B is 0.0012-0.0018%, the mass percentage of As is 0.025-0.035%, and the mass percentage of Sb is 0.025-0.045%.

4. The anti-zincification environmentally friendly copper alloy for faucets according to claim 1, characterized in that, The sum of the mass percentages of Fe and Sn is 0.16-0.22%.

5. A method for preparing a dezincification-resistant, environmentally friendly copper alloy for faucets as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Weigh out 65 brass scrap, 62 brass scrap, tin copper, cupronickel, lead-free brass, copper, Zn, Al, As, Sb, and Pb as raw materials according to the formula, add a refining agent, and remove iron. S2: The weighed raw materials are put into an electric melting furnace and melted at 1050℃-1150℃. During the melting process, a slag remover is added and at least one high-temperature blasting treatment is carried out. S3: After flame treatment, add slag remover again, let stand, and then cast into shape.

6. The method for preparing the anti-zinc dezincification environmentally friendly copper alloy for faucets according to claim 5, characterized in that, In S1, the addition amounts of each raw material by mass percentage are as follows: 37.4-37.5% 65 brass scrap, 7% 62 brass scrap, 0.7% tin copper, 0.2% cupronickel, 32% lead-free brass, 14% copper, 8% Zn, 0.56% Al, 0.02% As, 0.02% Sb, and 0.1% Pb.

7. The method for preparing the anti-zinc dezincification environmentally friendly copper alloy for faucets according to claim 5, characterized in that, In S2, the order of feeding raw materials into the furnace is as follows: 65 brass scrap, 62 brass scrap, lead-free bran, cupronickel, copper, tin-copper, Zn, Al, As, Sb, Pb; among them, 65 brass scrap and 62 brass scrap are fed into the furnace first and slag is removed, then lead-free bran and cupronickel and the first slag remover are added, and after slag removal again, the remaining raw materials are added for high-temperature smelting.

8. The method for preparing the anti-zinc dezincification environmentally friendly copper alloy for faucets according to claim 5, characterized in that, The high-temperature flame treatment is carried out in two stages: the first flame treatment is carried out during the smelting process, and after the flame is applied, the sample is taken for analysis of the composition and polishing effect; the second flame treatment is carried out after the composition analysis meets the standards, and after the flame is applied, the sample is taken for another settling process, and then the casting is carried out.

9. The method for preparing the anti-zinc dezincification environmentally friendly copper alloy for faucets according to claim 5, characterized in that, The refining agent is a boron refining agent, and the slag remover is a glassy slag remover.

10. The method for preparing the anti-zinc dezincification environmentally friendly copper alloy for faucets according to claim 5, characterized in that, In step S3, after the flame treatment, a slag remover is added again, and the settling time is 5 minutes before casting.

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