Lead-free silicon brass alloy and preparation method and application thereof

Abstract

The invention relates to a lead-free silicon brass alloy which comprises the following components: 0.005% < = mB < = 0.02%; 0.4% < = mAl < = 0.8%; 0.4% < = mSi < = 0.7%; 0.004% < = mP < = 0.02%; 0.005% < = mAs < = 0.02%; 60.0% < = mCu < = 64.0%; and mBi is not less than 0.005% and not more than 0.02%. According to the lead-free silicon brass alloy, the problems of tool abrasion and chip removal in the cutting process are effectively reduced through dispersion distribution of hard and brittle phases and a blocky alpha-phase structure, and the cutting performance is remarkably improved; the stability of the lead-free silicon brass alloy in a corrosive environment is improved through the compact tissue structure and the reduced electrode potential, and the dezincification corrosion resistance is remarkably improved; meanwhile, the structure is more compact, the overall performance is improved, and the service life is prolonged; in addition, by adding the phosphorus element and increasing the proportion of the copper element, the casting flowability and the processing performance are optimized, and the method is suitable for large-scale production; most importantly, no harmful lead element is contained, the environment-friendly requirement is met, the use is safer and more harmless, and the environment-friendly water-based paint is suitable for the field of household bathroom accessories with higher requirements on environment friendliness and safety.

Description

Technical Field

[0001] The invention relates to the technical field of copper-based alloys, and in particular to a lead-free silicon brass alloy and a preparation method and application thereof. Background Art

[0002] Lead brass is an alloy with copper and zinc as the base and a small amount of lead added. Due to the presence of lead, lead brass has good cold and hot forming properties, cutting performance and corrosion resistance, and is widely used in instrument parts, electrical connectors, water pipes, faucets and valves in the bathroom industry and other parts. However, lead is a heavy metal that is seriously harmful to the human body and the environment. When lead brass is used in bathroom piping systems, lead will dissolve under the scouring and immersion of water and enter the water, causing serious harm to human health and the environment. Therefore, with the improvement of environmental awareness, the application scenarios of lead brass are limited, especially in the field of home bathroom, and are gradually replaced by lead-free copper alloy products.

[0003] In order to replace lead brass, the market currently mainly improves the machining performance of the alloy by adding elements with similar performance to lead (such as Si, P, Ca, Sb, or Bi, etc.). However, these replacement elements have various problems: the addition of phosphorus (P) will cause hard spots and pores, calcium (Ca) raw materials are difficult to obtain and will cause fluidity to deteriorate, antimony (Sb) has certain toxicity, and bismuth (Bi) has the risk of cracking. The current mainstream solution is to improve the cutting performance and comprehensive performance of brass to a certain extent by adding silicon.

[0004] However, with the continuous development and improvement of the sanitary ware industry, the demand for materials is increasing, and the quality requirements are also increasing. Therefore, there is an urgent need for a lead-free silicon brass alloy and its preparation method and application. Summary of the invention

[0005] The purpose of the present invention is to provide a lead-free silicon brass alloy and a preparation method and application thereof in view of the deficiencies in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention is to provide a lead-free silicon brass alloy, comprising: B, Al, Si, P, As, Zn, Cu, Bi, and inevitable impurities; wherein:

[0008] 0.005%≤m B ≤0.02%;0.4%≤m Al ≤0.8%;0.4%≤m Si ≤0.7%;0.004%≤m P ≤0.02%;0.005%≤m As ≤0.02%;60.0%≤mCu ≤64.0%;0.005%≤m Bi ≤0.02%;

[0009] Among them, m B represents the mass percentage of B in the lead-free silicon brass alloy, m Al represents the mass percentage of Al in the lead-free silicon brass alloy, m Si represents the mass percentage of Si in the lead-free silicon brass alloy, m P represents the mass percentage of P in the lead-free silicon brass alloy, m As represents the mass percentage of As in the lead-free silicon brass alloy, m Cu represents the mass percentage of Cu in the lead-free silicon brass alloy, m Bi represents the mass percentage of the Bi in the lead-free silicon brass alloy, and the Zn and the impurities are the remaining components in the lead-free silicon brass alloy;

[0010] Furthermore, the lead-free silicon brass alloy includes a matrix phase and a second phase; the matrix phase includes a bulk α phase and a β phase, and the second phase includes a γ phase and a κ phase.

[0011] In the lead-free silicon brass alloy of the present invention, Si element is added to form intermetallic compounds such as Cu5Si3, which are dispersed at grain boundaries and in grains. Since copper-silicon intermetallic compounds belong to hard and brittle phases, they act as chip-breaking particles during machining to avoid continuous cutting chip foam, thereby reducing the impact on tool machining and chip removal; P element is added and the addition ratio is controlled to improve the fluidity of the cast copper ingot without increasing the hard particles of Cu3P; As element is added to increase the electrode potential of the α phase and reduce the electrode potential of copper, thereby obtaining better dezincification resistance; Bi element is added, which is mainly distributed at the grain boundaries to improve the cutting performance; the proportion of Cu element is increased to improve the fluidity of the melt, thereby improving the casting performance of the alloy; adding a second phase can improve the mechanical processing performance of the alloy, the γ phase is hard and brittle, and can play a role in chip breaking during cutting, and the κ phase is also hard and brittle, which helps to improve the processing performance of the material, but because it has a greater risk of brittle cracking, its proportion is relatively low, and it needs to be decomposed into the γ phase as much as possible.

[0012] Preferably, the area percentage of the β phase is 50%-75%.

[0013] In the lead-free silicon brass alloy of the present invention, the β phase can effectively enhance the cutting effect. When the area percentage of the β phase is less than 50%, the cutting tool will stick and the chip removal will be poor. When the area percentage of the β phase is higher than 75%, the alloy will become brittle and crack. Preferably, the area percentage of the γ phase is greater than the area percentage of the κ phase.

[0014] Furthermore, the ratio of the area percentage of the κ phase to the area percentage of the γ phase is less than 0.1.

[0015] In the lead-free silicon brass alloy of the present invention, the κ phase helps to improve the processing performance of the material, but because it has a greater risk of brittle cracking, it is necessary to decompose at least 90% of the κ phase into the γ phase to ensure the processing performance of the alloy at room temperature. Preferably, the grain size of the lead-free silicon brass alloy is not higher than 25 μm.

[0016] In the lead-free silicon brass alloy of the present invention, the structure with a grain size of no more than 25 μm can strengthen the comprehensive performance of the material, not only can improve the machining performance, but also can obtain better mechanical properties, corrosion resistance and the like.

[0017] The second aspect of the present invention is to provide a method for preparing the lead-free silicon brass alloy as described above, the steps comprising:

[0018] S1, taking a grain refiner, a copper raw material, a silicon raw material, a bismuth raw material, an arsenic raw material, a zinc raw material, and an aluminum raw material, mixing and smelting them in sequence, and heat-insulating and standing them to obtain a first material;

[0019] S2, adding a rare earth alloy, a slag removal agent, and a refining agent to the first material, performing slag removal treatment, and obtaining a second material;

[0020] S3, adding the refining agent to the second material at 1000°C-1030°C, stirring for 30s-1min; heating to 1090°C-1130°C, keeping the temperature for 1min-2min, adding phosphorus raw material, and obtaining the third material;

[0021] S4, sampling the third material, and sequentially performing a composition test, a polishing quality test, a fluidity test, and an overall mirror effect test on the sample;

[0022] If any test criteria are not met, return to S3;

[0023] If all test criteria are met, proceed to S5;

[0024] S5. Casting the third material to obtain the lead-free silicon brass alloy.

[0025] Preferably, the grain refiner comprises, by weight: 40-60 parts of potassium fluoroborate, 30-50 parts of aluminum powder, and 8-10 parts of boron powder.

[0026] In the present invention, the grain refiner is used to generate the core of the grain structure, breed high melting point compounds, act on the melt, and refine the grain structure. This dense structure is conducive to the uniform distribution of the cutting phase and is also conducive to improving the material's resistance to dezincification corrosion.

[0027] Preferably, the S1 includes:

[0028] First, add the grain refiner and the copper raw material, and then add brass scraps, the silicon raw material, the bismuth raw material and the copper-arsenic alloy after the added materials are melted, and then add brass powder after the added materials are melted, and then add the zinc raw material and the aluminum raw material after the added materials are melted, and then keep the added materials warm and stand still to obtain the first material.

[0029] Preferably, the temperature during the heat preservation and standing is 1000°C-1030°C, and the time is 5min-10min.

[0030] Preferably, the S2 includes:

[0031] The rare earth alloy, the slag removal agent, and the refining agent are added to the first material, and after being fully stirred, the temperature is raised to 1090° C.-1130° C. and maintained for 10 seconds-30 seconds, and slag removal is performed to obtain the second material.

[0032] Preferably, in S4,

[0033] The standard of the composition test is to determine whether the composition of the sample meets 0.005% ≤ m B ≤0.02%;0.4%≤m Al ≤0.8%;0.4%≤m Si ≤0.7%;0.004%≤m P ≤0.02%;0.005%≤m As ≤0.02%;60.0%≤m Cu ≤64.0%;0.005%≤m Bi ≤0.02%;

[0034] The standard of the polishing quality test is to determine whether there are hard spots on the inner wall of the cup sample obtained by the cup throwing test;

[0035] The standard of the fluidity test is to determine whether the flow length of the sample taken in the annular flow channel is greater than 380 mm;

[0036] The standard for the overall mirror effect test is to determine whether the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is greater than 175°.

[0037] The third aspect of the present invention is to provide a use of the lead-free silicon brass alloy as described above in the preparation of sanitary products.

[0038] The present invention adopts the above technical solution, and has the following technical effects compared with the prior art:

[0039] The dispersed distribution of the hard and brittle phases and the agglomerated α-phase structure in the lead-free silicon brass alloy of the present invention effectively reduce tool wear and chip removal problems during the cutting process, and significantly improve the cutting performance to 75%-80% of HPb63-3%; the dense organizational structure and the reduced electrode potential improve the stability of the lead-free silicon brass alloy in a corrosive environment, significantly improve the dezincification corrosion resistance, and stabilize within 200μm; at the same time, the organization of the lead-free silicon brass alloy is denser, and the overall performance and service life are improved; in addition, by adding phosphorus elements and increasing the proportion of copper elements, the casting fluidity and processing performance are optimized, and it is suitable for large-scale production; most importantly, the lead-free silicon brass alloy of the present invention does not contain harmful lead elements, meets environmental protection requirements, is safer and harmless to use, and is suitable for the field of home bathrooms with high requirements for environmental protection and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a metallographic diagram of the lead-free silicon brass alloy in Example 1 of the present invention;

[0041] Figure 2 is a metallographic diagram of the lead-free silicon brass alloy in Example 2 of the present invention;

[0042] Figure 3 is a metallographic diagram of the lead-free silicon brass alloy in Example 3 of the present invention;

[0043] Figure 4 It is the metallographic diagram of the lead-free silicon brass alloy in the comparative example of the present invention. DETAILED DESCRIPTION

[0044] The specific embodiments of the present invention will be described in detail below.

[0045] Unless otherwise defined, technical or scientific terms used in the claims and the specification shall have the common meanings understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0046] The words "include" or similar words used in the patent application specification and claims of the present invention mean that the items appearing before "include" include the items listed after "include" or their equivalents, and do not exclude other items.

[0047] The numerical values ​​mentioned in the present invention include all numerical values ​​that increase from low to high by one unit, assuming that there are at least two units between any lower value and the higher value. For example, if a component or a physical quantity is said to be from 1 to 100, 10 to 90 is more preferred, and 20 to 80 is the most preferred, it is intended to express that values ​​such as 5 to 95, 14 to 76, 23 to 67, 32 to 58, 41 to 49 are clearly listed in this specification; for values ​​less than 1, 0.0001, 0.001, 0.01 or 0.1 are considered to be more suitable as a unit. The above examples are for illustrative purposes only. In fact, all numerical combinations between the lowest value and the highest value listed are deemed to be clearly listed in this specification in a similar manner.

[0048] Example 1

[0049] This embodiment provides a lead-free silicon brass alloy and a preparation method thereof, the preparation steps comprising:

[0050] S1. In a 3t power frequency furnace, 1.2kg of grain refiner and 1100kg of 1# copper rice are first added, and after the added materials are melted, 300kg of H62 brass scrap, 18.2kg of elemental silicon, 0.28kg of elemental bismuth and 1.12kg of copper-arsenic alloy (wherein the mass percentage of arsenic is 20%) are added, and after the added materials are melted, 700kg of drawing powder is added, and after the added materials are melted, 667.52kg of 0# zinc ingot and 12.88kg of aluminum ingot are added, and after the added materials are melted, they are kept at 1020°C for 5 minutes to obtain the first material;

[0051] Wherein, the grain refiner comprises, by weight: 50 parts of potassium fluoroborate, 40 parts of aluminum powder, and 10 parts of boron powder;

[0052] S2, press 0.2 kg of rare earth alloy into the liquid surface of the first material, sprinkle 2 kg of slag cleaning agent on the liquid surface of the first material, press 2 kg of refining agent into the liquid surface of the first material, after sufficient stirring, heat to 1090 ° C and keep for 20 seconds, carry out slag removal treatment, and obtain the second material;

[0053] S3, at 1000°C, press 2 kg of the refining agent into the liquid surface of the first material, stir for 40 seconds; after heating to 1090°C, keep warm for 1 minute, add 1.72 kg of copper-phosphorus alloy (wherein the mass percentage of phosphorus is 13%), and obtain the third material;

[0054] S4, taking a sample at 200 mm below the liquid surface of the third material, and performing a component test on the sample;

[0055] During the component test, the third material is kept at 1000° C. and allowed to stand;

[0056] If the composition test standard is met, the temperature is raised to 1110° C., and a new sample is taken at 200 mm below the liquid surface of the third material. The sample is then subjected to a polishing quality test, a fluidity test, and an overall mirror effect test in sequence;

[0057] If all test criteria are met, proceed to S5;

[0058] If any test criteria are not met, return to S3;

[0059] The standard of the composition test is to determine whether the composition of the sample meets 0.005% ≤ m B ≤0.02%;0.4%≤m Al ≤0.8%;0.4%≤m Si ≤0.7%;0.004%≤m P ≤0.02%;0.005%≤m As ≤0.02%;60.0%≤m Cu ≤64.0%;0.005%≤m Bi ≤0.02%;

[0060] The polishing quality test standard is to determine whether there are hard spots on the inner wall of the cup sample obtained by the cup-throwing test;

[0061] The standard of the fluidity test is to determine whether the flow length of the sample taken in the annular flow channel is greater than 380 mm;

[0062] The standard for the overall mirror effect test is to determine whether the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is greater than 175°;

[0063] S5. Casting the third material to obtain the lead-free silicon brass alloy.

[0064] In this embodiment, the result of the composition test of the third material is m B =0.01%; m Al =0.46%; m Si =0.65%; m P =0.008%; m As =0.008%; m Cu =61.3%; m Bi =0.01%; meets the standard of ingredient testing;

[0065] The result of the polishing quality test of the third material is that there are no hard spots or pores remaining on the inner wall of the cup sample obtained by the cup-throwing test, which meets the standard of the polishing quality test;

[0066] The result of the fluidity test of the third material is that the flow length of the sample taken in the annular flow channel is 395 mm, which meets the standard of the fluidity test;

[0067] The result of the overall mirror effect test of the third material is that the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is 177°, which meets the standard of the overall mirror effect test.

[0068] The metallographic analysis results of the lead-free silicon brass alloy obtained in this embodiment are as follows: Figure 1 As shown, it is mainly composed of α phase and β phase, the grain structure is fine and uniform, the area percentage of the β phase is 65%, the grain size is 25μm, no abnormal mixed crystal phenomenon or abnormal local structure phenomenon is observed, the dezincification corrosion resistance is 120μm / 150μm / 120μm / 145μm / 100μm, and the cutting performance is 75%HPb63-3%.

[0069] Example 2

[0070] This embodiment provides a lead-free silicon brass alloy and a preparation method thereof, the preparation steps comprising:

[0071] S1. In a 3t power frequency furnace, 1.2kg of grain refiner and 1200kg of 1# copper rice are first added, and after the added materials are melted, 300kg of H62 brass scrap, 15.4kg of elemental silicon, 0.336kg of elemental bismuth and 1.68kg of copper-arsenic alloy (wherein the mass percentage of arsenic is 20%) are added, and after the added materials are melted, 600kg of drawing powder is added, and after the added materials are melted, 664.34kg of 0# zinc ingot and 15.68kg of aluminum ingot are added, and after the added materials are melted, they are kept at 1010°C for 5 minutes to obtain the first material;

[0072] Wherein, the grain refiner comprises, by weight: 60 parts of potassium fluoroborate, 30 parts of aluminum powder, and 10 parts of boron powder;

[0073] S2, press 0.2 kg of rare earth alloy into the liquid surface of the first material, sprinkle 2 kg of slag cleaning agent on the liquid surface of the first material, press 2 kg of refining agent into the liquid surface of the first material, after sufficient stirring, heat to 1090 ° C and keep for 20 seconds, carry out slag removal treatment, and obtain the second material;

[0074] S3, at 1000°C, press 2 kg of the refining agent into the liquid surface of the first material, stir for 50 seconds; after heating to 1090°C, keep warm for 1 minute, add 2.36 kg of copper-phosphorus alloy (wherein the mass percentage of phosphorus is 13%), and obtain the third material;

[0075] S4, taking a sample at 200 mm below the liquid surface of the third material, and performing a component test on the sample;

[0076] During the component test, the third material is kept at 1000° C. and allowed to stand;

[0077] If the composition test standard is met, the temperature is raised to 1110° C., and a new sample is taken at 200 mm below the liquid surface of the third material. The sample is then subjected to a polishing quality test, a fluidity test, and an overall mirror effect test in sequence;

[0078] If all test criteria are met, proceed to S5;

[0079] If any test criteria are not met, return to S3;

[0080] The standard of the composition test is to determine whether the composition of the sample meets 0.005% ≤ m B ≤0.02%;0.4%≤m Al ≤0.8%;0.4%≤m Si ≤0.7%;0.004%≤m P ≤0.02%;0.005%≤m As ≤0.02%;60.0%≤m Cu ≤64.0%;0.005%≤m Bi ≤0.02%;

[0081] The polishing quality test standard is to determine whether there are hard spots on the inner wall of the cup sample obtained by the cup-throwing test;

[0082] The standard of the fluidity test is to determine whether the flow length of the sample taken in the annular flow channel is greater than 380 mm;

[0083] The standard for the overall mirror effect test is to determine whether the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is greater than 175°;

[0084] S5. Casting the third material to obtain the lead-free silicon brass alloy.

[0085] In this embodiment, the result of the composition test of the third material is m B =0.012%; m Al =0.56%; m Si =0.55%; m P =0.011%; m As =0.012%; m Cu =62.3%; m Bi =0.012%; meets the standard of component testing;

[0086] The result of the polishing quality test of the third material is that there are no hard spots or pores remaining on the inner wall of the cup sample obtained by the cup-throwing test, which meets the standard of the polishing quality test;

[0087] The result of the fluidity test of the third material is that the flow length of the sample taken in the annular flow channel is 395 mm, which meets the standard of the fluidity test;

[0088] The result of the overall mirror effect test of the third material is that the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is 178°, which meets the standard of the overall mirror effect test.

[0089] The metallographic analysis results of the lead-free silicon brass alloy obtained in this embodiment are as follows: Figure 2 As shown, it is mainly composed of α phase and β phase, the grain structure is fine and uniform, the area percentage of the β phase is 60%, the grain size is 25μm, no abnormal mixed crystal phenomenon or abnormal phenomenon of local structure is observed, the dezincification corrosion resistance is 150μm / 140μm / 130μm / 155μm / 120μm, and the cutting performance is 80%HPb63-3%.

[0090] Example 3

[0091] This embodiment provides a lead-free silicon brass alloy and a preparation method thereof, the preparation steps comprising:

[0092] S1. In a 3t power frequency furnace, 1.2kg of grain refiner and 900kg of 1# copper rice are first added, and after the added materials are melted, 300kg of H62 brass scrap, 18.2kg of elemental silicon, 0.28kg of elemental bismuth and 2.52kg of copper-arsenic alloy are added, and after the added materials are melted, 900kg of drawing powder is added, and after the added materials are melted, 660.19kg of 0# zinc ingot and 15.68kg of aluminum ingot are added, and after the added materials are melted, they are kept at 1015°C for 5min to obtain the first material;

[0093] Wherein, the grain refiner comprises, by weight: 55 parts of potassium fluoroborate, 35 parts of aluminum powder, and 10 parts of boron powder;

[0094] S2, press 0.2 kg of rare earth alloy into the liquid surface of the first material, sprinkle 2 kg of slag cleaning agent on the liquid surface of the first material, press 2 kg of refining agent into the liquid surface of the first material, after sufficient stirring, heat to 1090 ° C and keep for 20 seconds, carry out slag removal treatment, and obtain the second material;

[0095] S3, at 1000°C, press 2 kg of the refining agent into the liquid surface of the first material, stir for 35 seconds; after heating to 1090°C, keep warm for 1 minute, add 2.36 kg of copper-phosphorus alloy (wherein the mass percentage of phosphorus is 13%), and obtain the third material;

[0096] S4, taking a sample at 200 mm below the liquid surface of the third material, and performing a component test on the sample;

[0097] During the component test, the third material is kept at 1000° C. and allowed to stand;

[0098] If the composition test standard is met, the temperature is raised to 1110° C., and a new sample is taken at 200 mm below the liquid surface of the third material. The sample is then subjected to a polishing quality test, a fluidity test, and an overall mirror effect test in sequence;

[0099] If all test criteria are met, proceed to S5;

[0100] If any test criteria are not met, return to S3;

[0101] The standard of the composition test is to determine whether the composition of the sample meets 0.005% ≤ m B ≤0.02%;0.4%≤m Al ≤0.8%;0.4%≤m Si ≤0.7%;0.004%≤m P ≤0.02%;0.005%≤m As ≤0.02%;60.0%≤m Cu ≤64.0%;0.005%≤m Bi ≤0.02%;

[0102] The polishing quality test standard is to determine whether there are hard spots on the inner wall of the cup sample obtained by the cup-throwing test;

[0103] The standard of the fluidity test is to determine whether the flow length of the sample taken in the annular flow channel is greater than 380 mm;

[0104] The standard for the overall mirror effect test is to determine whether the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is greater than 175°;

[0105] S5. Casting the third material to obtain the lead-free silicon brass alloy.

[0106] In this embodiment, the result of the composition test of the third material is m B =0.01%; m Al =0.56%; mSi =0.65%; m P =0.009%; m As =0.018%; m Cu =63.3%; m Bi =0.01%; meets the standard of ingredient testing;

[0107] The result of the polishing quality test of the third material is that there are no hard spots or pores remaining on the inner wall of the cup sample obtained by the cup-throwing test, which meets the standard of the polishing quality test;

[0108] The result of the fluidity test of the third material is that the flow length of the sample taken in the annular flow channel is 405 mm, which meets the standard of the fluidity test;

[0109] The result of the overall mirror effect test of the third material is that the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is 177°, which meets the standard of the overall mirror effect test.

[0110] The metallographic analysis results of the lead-free silicon brass alloy obtained in this embodiment are as follows: Figure 3 As shown, it is mainly composed of α phase and β phase, the grain structure is fine and uniform, the area percentage of the β phase is 60%, the grain size is 25μm, no abnormal mixed crystal phenomenon or abnormal local structure phenomenon is observed, the dezincification corrosion resistance is 110μm / 120μm / 140μm / 155μm / 120μm, and the cutting performance is 75%HPb63-3%.

[0111] Comparative Example

[0112] This embodiment provides a lead-free silicon brass alloy and a preparation method thereof, the preparation steps comprising:

[0113] S1. In a 3t power frequency furnace, first add 1.2kg of grain refiner and 1100kg of 1# copper rice, and then add 800kg of H62 brass scraps and 6.02kg of elemental lead after the added materials are melted, and then add 200kg of wire drawing powder after the added materials are melted, and then add 692.78kg of 0# zinc ingot after the added materials are melted, and after the added materials are melted, keep warm at 1010°C for 5min to obtain the first material;

[0114] Wherein, the grain refiner comprises: potassium fluorotitanate;

[0115] S2, press 0.2 kg of rare earth alloy into the liquid surface of the first material, sprinkle 2 kg of slag cleaning agent on the liquid surface of the first material, press 2 kg of refining agent into the liquid surface of the first material, after sufficient stirring, heat to 1090 ° C and keep for 20 seconds, carry out slag removal treatment, and obtain the second material;

[0116] S3, at 1000°C, press 2 kg of the refining agent into the liquid surface of the first material, stir for 45 seconds; heat to 1090°C, keep warm for 1 minute, and obtain the third material;

[0117] S4, taking a sample at 200 mm below the liquid surface of the third material, and performing a component test on the sample;

[0118] During the component test, the third material is kept at 1000° C. and allowed to stand;

[0119] The temperature was raised to 1110° C., and new samples were taken at 200 mm below the liquid surface of the third material. The samples were then subjected to a polishing quality test, a fluidity test, and an overall mirror effect test.

[0120] In this comparative example, the result of the composition test of the third material is m Cu =62.5%; m Pb =2.15%;

[0121] The result of the polishing quality test of the third material is that there are no hard spots or pores remaining on the inner wall of the cup sample obtained by the cup-throwing test;

[0122] The result of the fluidity test of the third material is that the flow length of the sample taken in the annular flow channel is 165 mm, and the casting fluidity is average;

[0123] The result of the overall mirror effect test of the third material is that the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is 165°, the solidification shrinkage is general, the recognition is poor, and there is looseness in the late solidification stage.

[0124] The metallographic analysis results of the lead-free silicon brass alloy obtained in this embodiment are as follows: Figure 4 As shown, it is mainly composed of α phase, β phase, and Pb phase, with well-developed dendritic structure. The area percentage of the β phase is 40%, the grain size is 40μm, significant abnormal mixed crystal phenomenon and abnormally proliferated local tissue grains are observed, the dezincification corrosion resistance is 300μm / 320μm / 340μm / 255μm / 220μm, and the cutting performance is 85%HPb63-3%.

[0125] In summary, the dispersed distribution of the hard and brittle phases and the agglomerated α-phase structure in the lead-free silicon brass alloy of the present invention effectively reduce tool wear and chip removal problems during cutting, and significantly improve the cutting performance to 75%-80% of HPb63-3%; the dense organizational structure and reduced electrode potential improve the stability of the lead-free silicon brass alloy in a corrosive environment, significantly improve the dezincification corrosion resistance, and stabilize within 200 μm; at the same time, the organization of the lead-free silicon brass alloy is denser, and the overall performance and service life are improved; in addition, by adding phosphorus and increasing the proportion of copper, the casting fluidity and processing performance are optimized, which is suitable for large-scale production; most importantly, the lead-free silicon brass alloy of the present invention does not contain harmful lead elements, meets environmental protection requirements, is safer and harmless to use, and is suitable for the field of home bathrooms with high requirements for environmental protection and safety.

[0126] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A lead-free silicon brass alloy, characterized in that: include: B, Al, Si, P, As, Zn, Cu, Bi, and unavoidable impurities; among which, 0.005%≤m B ≤0.02%;0.4%≤m Al ≤0.8%;0.4%≤m Si ≤0.7%;0.004%≤m P ≤0.02%;0.005%≤m As ≤0.02%;60.0%≤m Cu ≤64.0%;0.005%≤m Bi ≤0.02%; Among them, m B represents the mass percentage of B in the lead-free silicon brass alloy, m Al represents the mass percentage of Al in the lead-free silicon brass alloy, m Si represents the mass percentage of Si in the lead-free silicon brass alloy, m P represents the mass percentage of P in the lead-free silicon brass alloy, m As represents the mass percentage of As in the lead-free silicon brass alloy, m Cu represents the mass percentage of Cu in the lead-free silicon brass alloy, m Bi represents the mass percentage of the Bi in the lead-free silicon brass alloy, and the Zn and the impurities are the remaining components in the lead-free silicon brass alloy; Furthermore, the lead-free silicon brass alloy includes a matrix phase and a second phase; the matrix phase includes a bulk α phase and a β phase, and the second phase includes a γ phase and a κ phase.

2. The lead-free silicon brass alloy according to claim 1, characterized in that: The area percentage of the β phase is 50%-75%; the area percentage of the γ phase is greater than the area percentage of the κ phase, and the ratio of the area percentage of the κ phase to the area percentage of the γ phase is less than 0.

1.

3. The lead-free silicon brass alloy according to claim 1, characterized in that: The grain size of the lead-free silicon brass alloy is not greater than 25 μm.

4. A method for preparing the lead-free silicon brass alloy according to any one of claims 1 to 3, characterized in that the steps include: S1, taking a grain refiner, a copper raw material, a silicon raw material, a bismuth raw material, an arsenic raw material, a zinc raw material, and an aluminum raw material, mixing and smelting them in sequence, and heat-insulating and standing them to obtain a first material; S2, adding a rare earth alloy, a slag removal agent, and a refining agent to the first material, performing slag removal treatment, and obtaining a second material; S3, adding the refining agent to the second material at 1000°C-1030°C, stirring for 30s-1min; heating to 1090°C-1130°C, keeping the temperature for 1min-2min, adding phosphorus raw material, and obtaining the third material; S4, sampling the third material, and sequentially performing a composition test, a polishing quality test, a fluidity test, and an overall mirror effect test on the sample; If the criteria of any test are not met, then return to S3; If all test criteria are met, proceed to S5; S5. Casting the third material to obtain the lead-free silicon brass alloy.

5. The preparation method according to claim 4, characterized in that: In parts by weight, the grain refiner includes: 40-60 parts of potassium fluoroborate, 30-50 parts of aluminum powder, and 8-10 parts of boron powder.

6. The preparation method according to claim 4, characterized in that: The S1 includes: First, add the grain refiner and the copper raw material, and then add brass scraps, the silicon raw material, the bismuth raw material and the copper-arsenic alloy after the added materials are melted, and then add brass powder after the added materials are melted, and then add the zinc raw material and the aluminum raw material after the added materials are melted, and then keep the added materials warm and stand still to obtain the first material.

7. The preparation method according to claim 4 or 6, characterized in that: The temperature of the heat preservation and standing is 1000° C.-1030° C., and the time is 5 min-10 min.

8. The preparation method according to claim 4, characterized in that: The S2 includes: The rare earth alloy, the slag removal agent, and the refining agent are added to the first material, and after being fully stirred, the temperature is raised to 1090° C.-1130° C. and maintained for 10 seconds-30 seconds, and slag removal is performed to obtain the second material.

9. The preparation method according to claim 4, characterized in that: In S4, The standard of the composition test is to determine whether the composition of the sample meets 0.005% ≤ m B ≤0.02%;0.4%≤m Al ≤0.8%;0.4%≤m Si ≤0.7%;0.004%≤m P ≤0.02%;0.005%≤m As ≤0.02%; 60.0%≤m Cu ≤64.0%;0.005%≤m Bi ≤0.02%; The standard of the polishing quality test is to determine whether there are hard spots on the inner wall of the cup sample obtained by the cup throwing test; The standard of the fluidity test is to determine whether the flow length of the sample taken in the annular flow channel is greater than 380 mm; The standard for the overall mirror effect test is to determine whether the elevation angle formed by the sample after solidification and shrinkage with the horizontal plane is greater than 175°.

10. Use of the lead-free silicon brass alloy according to any one of claims 1 to 3 in the preparation of sanitary products.

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