Low-segregation aluminum-tin alloy round cast ingot and preparation method thereof

Abstract

The invention provides a low-segregation aluminum-tin alloy round cast ingot and a preparation method thereof, and belongs to the technical field of aluminum alloy casting forming. The low-segregation aluminum-tin alloy round cast ingot provided by the invention is prepared from the following components in percentage by mass: 5.5 to 7.0 percent of Sn, 0.7 to 1.3 percent of Cu, 0.7 to 1.3 percent of Ni, less than or equal to 0.15 percent of Fe, 0.15 to 0.25 percent of Si, 0.15 to 0.25 percent of Zr, 0.01 to 0.20 percent of Ti, 0.15 to 0.25 percent of Sb, 0.02 to 0.10 percent of P and the balance of Al. By using various elements such as zirconium, titanium, silicon, antimony and phosphorus, a synergistic effect can be achieved, and the uniformity of the tin content of the aluminum-tin alloy is remarkably improved. The result of the embodiment shows that even if the diameter of the low-segregation aluminum-tin alloy round cast ingot is larger than or equal to 250 mm, the low-segregation aluminum-tin alloy round cast ingot cannot crack in the casting process, and meanwhile element distribution uniformity is good.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy casting and forming, and in particular to a low-segregation aluminum-tin alloy round ingot and a preparation method thereof. Background Art

[0002] A850 aluminum alloy is an aluminum-tin alloy containing about 6.5% tin. It has good compliance, anti-seizure performance, high wear resistance and corrosion resistance. It is cheap and has a low density. It is used in high-load situations and is in line with the development direction of modern engine miniaturization and lightweight. It is used as a bearing material in engines. At present, only a few manufacturers in China can independently produce A850 aluminum alloy, and most rely on imports.

[0003] The production processes of A850 aluminum alloy are mostly semi-solid casting and powder metallurgy forming. These two processes require special equipment, are complicated to operate, easily introduce oxide inclusions, are costly and have unstable performance.

[0004] Although the aluminum alloy round ingot produced by melting and casting has less oxidized slag, dense structure and good performance, the density of Al is 2.7g / cm due to the high content of tin in the A850 aluminum alloy. 3 , the density of Sn is 7g / cm 3 The density difference is too large, and the solubility of Sn in Al at room temperature is very small, which leads to segregation in the casting process, making the composition, structure and performance uniformity of A850 aluminum alloy round ingot produced by melting and casting poor. At the same time, the solid-liquid phase temperature difference of A850 aluminum-tin alloy is about 400℃. The large solid-liquid phase temperature difference increases the difficulty of casting in the production process, and the round ingot is very easy to crack, resulting in product scrapping and increased production costs.

[0005] Therefore, how to improve the composition uniformity of the aluminum-tin alloy and avoid cracking of the aluminum-tin alloy round ingot during the casting process has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0006] The object of the present invention is to provide a low-segregation aluminum-tin alloy round ingot and a preparation method thereof. The low-segregation aluminum-tin alloy round ingot provided by the present invention will not crack during the casting process even if the diameter is ≥250mm, and the element distribution uniformity in the aluminum-tin alloy is good.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The invention provides a low-segregation aluminum-tin alloy round ingot, which comprises the following components by mass percentage: Sn: 5.5-7.0%, Cu: 0.7-1.3%, Ni: 0.7-1.3%, Fe≤0.15%, Si: 0.15-0.25%, Zr: 0.15-0.25%, Ti: 0.01-0.20%, Sb: 0.15-0.25%, P: 0.02-0.10% and the balance of Al.

[0009] Preferably, the low segregation aluminum-tin alloy round ingot comprises the following components, measured by mass percentage: Sn: 6.0-6.5%, Cu: 0.8-1.2%, Ni: 0.8-1.2%, Fe≤0.15%, Si: 0.18-0.23%, Zr: 0.18-0.23%, Ti: 0.08-0.12%, Sb: 0.18-0.23%, P: 0.04-0.08% and the balance Al.

[0010] The present invention provides a method for preparing the low-segregation aluminum-tin alloy round ingot described in the above technical solution, comprising the following steps:

[0011] (1) subjecting an aluminum-tin alloy raw material to smelting, refining and modification treatment in sequence to obtain an aluminum-tin alloy melt;

[0012] (2) Casting the aluminum-tin alloy melt obtained in step (1) to obtain a low-segregation aluminum-tin alloy round ingot.

[0013] Preferably, the aluminum-tin alloy raw materials in step (1) include aluminum ingots, metallic silicon, tin blocks, copper plates, nickel plates, titanium agents, aluminum-zirconium master alloys, aluminum-antimony master alloys, aluminum-phosphorus master alloys and refining agents.

[0014] Preferably, the step of preparing the aluminum-tin alloy melt in step (1) is:

[0015] 1) mixing an aluminum ingot, metallic silicon, a copper plate, a nickel plate, a titanium agent and an aluminum-zirconium master alloy, and performing a first smelting to obtain a first alloy melt;

[0016] 2) adding a tin block and an aluminum-antimony master alloy to the first alloy melt obtained in step 1) to perform a second smelting to obtain a second alloy melt;

[0017] 3) adding a refining agent to the second alloy melt obtained in step 2) for refining to obtain a third alloy melt;

[0018] 4) adding an aluminum-phosphorus master alloy to the third alloy melt obtained in step 3) for modification to obtain an aluminum-tin alloy melt.

[0019] Preferably, the holding temperature of the first smelting in step 1) is 780-830°C.

[0020] Preferably, the insulation temperature of the second smelting in step 2) is 760-770° C., and the insulation time of the second smelting is 20-40 min.

[0021] Preferably, the refining agent in step 3) is a sodium-free refining agent, and the amount of the refining agent is 2 to 3 wt.‰ of the second alloy melt.

[0022] Preferably, the starting stage parameters of casting in step (2) are: starting length: 50 mm, casting speed 50-90 mm / min, cooling water: 10-21 t / h.

[0023] Preferably, the normal casting phase parameters of the casting in step (2) are: casting speed: 50-90 mm / min, cooling water: 10-21 t / h.

[0024] The invention provides a low-segregation aluminum-tin alloy round ingot, which comprises the following components by mass percentage: Sn: 5.5-7.0%, Cu: 0.7-1.3%, Ni: 0.7-1.3%, Fe≤0.15%, Si: 0.15-0.25%, Zr: 0.15-0.25%, Ti: 0.01-0.20%, Sb: 0.15-0.25%, P: 0.02-0.10% and the balance of Al. The present invention can make the aluminum alloy have good compliance, anti-seizure performance, high wear resistance and corrosion resistance by adding tin element; copper element can form solid solution with aluminum, thereby improving the fluidity, strength and hardness of the alloy; nickel element can form metal compounds such as NiAl3 with aluminum, thereby improving the strength, hardness and dimensional stability of the aluminum-tin alloy; silicon element improves the casting performance of the alloy, silicon and aluminum can form a solid solution, improve the high-temperature fluidity of the alloy, improve wear resistance, reduce thermal cracking tendency and shrinkage, thereby reducing the probability of cracking of the aluminum-tin alloy during the casting process, and further improving the processing performance of the aluminum-tin alloy round ingot; zirconium element can form ZrAl3 compound with aluminum, which can It hinders the recrystallization process, refines the recrystallized grains, and can also refine the casting structure; titanium can significantly refine the grain structure of the aluminum-tin alloy, improve the mechanical properties of the alloy, and reduce the thermal cracking tendency of the alloy; antimony has a good modification effect on both hypoeutectic and hypereutectic aluminum-silicon alloys, and can make the grains of eutectic silicon after refinement thin-layered; phosphorus exists as a modifier, which can refine the primary silicon precipitated in the alloy and improve the uniformity of the tin content of the aluminum-tin alloy, thereby achieving uniform organization and performance of the aluminum-tin alloy; by using a variety of added elements such as zirconium, titanium, silicon, antimony and phosphorus, a good synergistic effect can be achieved, significantly improving the uniformity of the tin content of the aluminum-tin alloy. The results of the embodiment show that the low-segregation aluminum-tin alloy round ingot provided by the present invention has no cracking phenomenon, and the tin content range in the aluminum-tin alloy round ingot is about 0.3-0.375%, and the segregation rate is about 4-6%, indicating that the tin content is very uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a physical picture of the low segregation aluminum-tin alloy round ingot prepared in Example 1;

[0026] Figure 2 This is a physical picture of the cross section of the low segregation aluminum-tin alloy round ingot prepared in Example 1;

[0027] Figure 3 This is a physical picture of the aluminum-tin alloy round ingot prepared in Comparative Example 2. DETAILED DESCRIPTION

[0028] The invention provides a low-segregation aluminum-tin alloy round ingot, which comprises the following components by mass percentage: Sn: 5.5-7.0%, Cu: 0.7-1.3%, Ni: 0.7-1.3%, Fe≤0.15%, Si: 0.15-0.25%, Zr: 0.15-0.25%, Ti: 0.01-0.20%, Sb: 0.15-0.25%, P: 0.02-0.10% and the balance of Al.

[0029] The low segregation aluminum-tin alloy round ingot provided by the present invention includes Sn: 5.5-7.0%, preferably 6.0-6.5%, by mass percentage. The present invention can make the aluminum alloy have good compliance, anti-seizure performance, high wear resistance and corrosion resistance by adding a certain amount of tin element to the aluminum alloy; however, the solubility of tin element in aluminum is too low and the density difference is large, which is easy to produce component segregation, and the solid-liquid phase line gap of this type of alloy is too large, which is easy to crack during the casting process. In order to obtain good compliance, wear resistance and high load capacity, the alloy controls its content within the range of 5.5-7.0%.

[0030] The low segregation aluminum-tin alloy round ingot provided by the present invention includes Cu: 0.7-1.3%, preferably 0.8-1.2%, more preferably 0.9-1.1%, and further preferably 1.0%, by mass percentage. In the present invention, the copper element can form a solid solution with aluminum, thereby improving the fluidity, strength and hardness of the alloy; but the addition of copper will also reduce the corrosion resistance and plasticity of the aluminum-tin alloy and increase its hot cracking tendency, so its content is controlled within the range of 0.7-1.3%.

[0031] The low segregation aluminum-tin alloy round ingot provided by the present invention includes Ni: 0.7-1.3%, preferably 0.8-1.2%, more preferably 0.9-1.1%, and further preferably 1.0%, by mass percentage. In the present invention, the nickel element can form metal compounds such as NiAl3 with aluminum to improve the strength, hardness and dimensional stability of the aluminum-tin alloy; however, the nickel element will also reduce the corrosion resistance of the aluminum-tin alloy, and the nickel element is expensive, so its content is controlled within the range of 0.7-1.3%.

[0032] The low segregation aluminum-tin alloy round ingot provided by the present invention includes Fe≤0.15%, preferably ≤0.12%, and more preferably 0.1%, by mass percentage. In the present invention, the Fe element is mainly an impurity element, which reduces the mechanical properties, reduces the fluidity of the alloy, and increases the hot cracking property, so its content is controlled to be below 0.15%.

[0033] The low segregation aluminum-tin alloy round ingot provided by the present invention comprises Si in an amount of 0.15-0.25%, preferably 0.18-0.23%, more preferably 0.19-0.22%, and further preferably 0.20-0.21%, by mass percentage. In the present invention, silicon improves the casting properties of the alloy, and silicon and aluminum can form a solid solution, thereby improving the high-temperature fluidity of the alloy, improving the wear resistance, reducing the tendency to hot cracking and the shrinkage rate. At the same time, the addition of silicon can also improve the uniformity of tin in the aluminum-tin alloy, thereby reducing the probability of cracking of the aluminum-tin alloy during the casting process, and further improving the processing properties of the aluminum-tin alloy round ingot.

[0034] The low segregation aluminum-tin alloy round ingot provided by the present invention includes Zr in an amount of 0.15-0.25%, preferably 0.18-0.23%, more preferably 0.19-0.22%, and further preferably 0.20-0.21%, by mass percentage. In the present invention, zirconium can form ZrAl3 compound with aluminum, which can hinder the recrystallization process, refine the recrystallized grains, and refine the casting structure; however, the addition of zirconium will reduce the strengthening effect of titanium on the aluminum-tin alloy, so its content is controlled within the range of 0.15-0.25%.

[0035] The low segregation aluminum-tin alloy round ingot provided by the present invention comprises Ti: 0.01-0.20%, preferably 0.08-0.15%, by mass percentage. In the present invention, the titanium element can significantly refine the grain structure of the aluminum-tin alloy, improve the mechanical properties of the alloy, and at the same time improve the uniformity of tin in the aluminum-tin alloy and reduce the thermal cracking tendency of the alloy.

[0036] The low segregation aluminum-tin alloy round ingot provided by the present invention comprises Sb: 0.15-0.25%, preferably 0.18-0.23%, more preferably 0.19-0.22%, and further preferably 0.20-0.21%, by mass percentage. In the present invention, the antimony element has a good modification effect on both hypoeutectic and hypereutectic aluminum-silicon alloys, and can make the grains of refined eutectic silicon in a thin layer. At the same time, the antimony element can also improve the uniformity of the tin content of the aluminum-tin alloy.

[0037] The low segregation aluminum-tin alloy round ingot provided by the present invention comprises P in a mass percentage of 0.02-0.10%, preferably 0.04-0.08%, more preferably 0.05-0.07%, and further preferably 0.06%. In the present invention, phosphorus is present as a modifier, which can refine the primary silicon precipitated in the alloy and improve the uniformity of the tin content of the aluminum-tin alloy, thereby achieving uniform organization and performance of the aluminum-tin alloy; and the aluminum-phosphorus master alloy has a high cost, so its content is controlled within the range of 0.04-0.08%.

[0038] The low segregation aluminum-tin alloy round ingot provided by the present invention includes a balance of Al in terms of mass percentage. In the present invention, the Al element is a matrix element of the aluminum-tin alloy.

[0039] The present invention can make the aluminum-tin alloy have good compliance, anti-seizure performance, high wear resistance and corrosion resistance by adding tin element; copper element can form a solid solution with aluminum, thereby improving the fluidity, strength and hardness of the alloy; nickel element can form metal compounds such as NiAl3 with aluminum, thereby improving the strength, hardness and dimensional stability of the aluminum-tin alloy; silicon element improves the casting performance of the alloy, silicon and aluminum can form a solid solution, improve the high-temperature fluidity of the alloy, improve wear resistance, reduce thermal cracking tendency and shrinkage, thereby reducing the probability of cracking of the aluminum-tin alloy during the casting process, and further improving the processing performance of the aluminum-tin alloy round ingot; zirconium element can react with aluminum The formation of ZrAl3 compounds can hinder the recrystallization process, refine the recrystallized grains, and at the same time refine the casting structure; the titanium element can significantly refine the grain structure of the aluminum-tin alloy, improve the mechanical properties of the alloy, and reduce the thermal cracking tendency of the alloy; the antimony element can make the grains of the refined eutectic silicon appear in a thin layer; the phosphorus element exists as a modifier, which can refine the primary silicon precipitated in the alloy and at the same time improve the uniformity of the tin content of the aluminum-tin alloy, thereby achieving uniform structure and properties of the aluminum-tin alloy; by using a variety of added elements such as zirconium, titanium, silicon, antimony and phosphorus, a good synergistic effect can be achieved, which can significantly improve the uniformity of the tin content of the aluminum-tin alloy.

[0040] The present invention provides a method for preparing the low-segregation aluminum-tin alloy round ingot described in the above technical solution, comprising the following steps:

[0041] (1) subjecting an aluminum-tin alloy raw material to smelting, refining and modification treatment in sequence to obtain an aluminum-tin alloy melt;

[0042] (2) Casting the aluminum-tin alloy melt obtained in step (1) to obtain a low-segregation aluminum-tin alloy round ingot.

[0043] The invention sequentially performs smelting, refining and modification treatment on the aluminum-tin alloy raw material to obtain the aluminum-tin alloy melt.

[0044] In the present invention, the aluminum-tin alloy raw materials preferably include aluminum ingots, metallic silicon, tin blocks, copper plates, nickel plates, titanium agents, aluminum-zirconium master alloys, aluminum-antimony master alloys, aluminum-phosphorus master alloys and refining agents. In the present invention, the purity of the aluminum ingot is preferably ≥99.7wt.%; the copper plate is preferably an electrolytic copper plate. The present invention has no special restrictions on the specific source of the aluminum-tin alloy raw materials, and commercial products well known to those skilled in the art or methods well known to those skilled in the art can be used to prepare the raw materials themselves. The present invention has no special restrictions on the specific amount of the alloy raw materials, as long as the chemical composition of the low-segregation aluminum-tin alloy round ingot meets the requirements.

[0045] In the present invention, the step of preparing the aluminum-tin alloy melt is preferably:

[0046] 1) mixing an aluminum ingot, metallic silicon, a copper plate, a nickel plate, a titanium agent and an aluminum-zirconium master alloy, and performing a first smelting to obtain a first alloy melt;

[0047] 2) adding a tin block and an aluminum-antimony master alloy to the first alloy melt obtained in step 1) to perform a second smelting to obtain a second alloy melt;

[0048] 3) adding a refining agent to the second alloy melt obtained in step 2) for refining to obtain a third alloy melt;

[0049] 4) adding an aluminum-phosphorus master alloy to the third alloy melt obtained in step 3) for modification to obtain an aluminum-tin alloy melt.

[0050] In the present invention, the "first", "second" and "third" have no special meanings and are only used to distinguish between smelting and alloy melts.

[0051] The present invention preferably mixes aluminum ingots, metallic silicon, copper plates, nickel plates, titanium agents and aluminum-zirconium master alloys, and performs a first smelting to obtain a first alloy melt.

[0052] The present invention has no particular limitation on the mixing method, and the raw materials can be added in a manner well known to those skilled in the art.

[0053] In the present invention, the holding temperature of the first smelting is preferably 780-830°C, more preferably 790-820°C, and further preferably 800-810°C. The present invention has no particular limitation on the heating rate to the first smelting holding temperature, which can be determined according to the technical common sense of those skilled in the art. The present invention has no particular limitation on the holding time of the first smelting, which can be determined according to the technical common sense of those skilled in the art, as long as the raw materials can be completely melted.

[0054] After the first smelting is completed, the present invention preferably samples and analyzes the product of the first smelting. In the present invention, the sampling and analysis is preferably sampling and detecting the content of Fe, Si, Cu, Ni, Ti and Zr in the product. If the content is unqualified, it is adjusted to a qualified content, and if the content is qualified, the next step is performed. The present invention can ensure that the aluminum-tin alloy with the chemical composition meeting the requirements is obtained through sampling and analysis.

[0055] After obtaining the first alloy melt, the present invention preferably adds a tin block and an aluminum-antimony master alloy to the first alloy melt to perform a second smelting to obtain a second alloy melt.

[0056] In the present invention, the addition of the tin block and the aluminum-antimony master alloy is preferably carried out under stirring conditions. The present invention has no special limitation on the stirring rate, which can be determined according to the technical common sense of those skilled in the art. The present invention can ensure that the components in the alloy melt are evenly mixed by adding the tin block and the aluminum-antimony master alloy under stirring conditions.

[0057] In the present invention, the holding temperature of the second smelting is preferably 760-770°C; the holding time of the second smelting is preferably 20-40 minutes, more preferably 25-35 minutes, and further preferably 30 minutes. The present invention can ensure that the tin block and the aluminum-antimony master alloy are completely melted and evenly mixed by controlling the parameters of the second smelting.

[0058] After the second smelting is completed, the present invention preferably samples and analyzes the product of the second smelting. In the present invention, the sampling and analysis is preferably sampling and detecting the content of Fe, Si, Sn, Sb, Cu, Ni, Zr and Ti in the product. If the content is unqualified, it is adjusted to a qualified content, and if the content is qualified, the next step is performed. The present invention can ensure that the aluminum-tin alloy with the chemical composition meeting the requirements is obtained through sampling and analysis.

[0059] After obtaining the second alloy melt, the present invention preferably adds a refining agent to the second alloy melt for refining to obtain a third alloy melt.

[0060] In the present invention, the refining agent is preferably a sodium-free refining agent; the amount of the refining agent is preferably 2 to 3 wt.‰ of the second alloy melt. The present invention has no special limitation on the specific source of the sodium-free refining agent, and a commercially available sodium-free refining agent well known to those skilled in the art can be used. The present invention can reduce the impurity content in the alloy melt by adding a sodium-free refining agent for refining, thereby further improving the performance of the aluminum-tin alloy ingot.

[0061] In the present invention, the refining temperature is preferably 740-780°C, more preferably 760°C; the refining time is preferably 5-15 minutes, more preferably 10 minutes. The present invention can further improve the refining effect by controlling the refining temperature and time.

[0062] After the refining is completed, the present invention preferably performs slag removal on the refined product to obtain a third alloy melt. The present invention has no particular limitation on the specific operation of slag removal, and the slag removal operation well known to those skilled in the art can be used. The present invention can remove impurities by slag removal.

[0063] After obtaining the third alloy melt, the present invention preferably adds an aluminum-phosphorus master alloy to the third alloy melt for modification to obtain an aluminum-tin alloy melt.

[0064] In the present invention, the aluminum-phosphorus master alloy is preferably prepared under stirring conditions. The present invention has no particular limitation on the stirring rate, which can be determined according to the technical common sense of those skilled in the art. The present invention ensures that the aluminum-phosphorus master alloy is mixed uniformly after being melted by adding the aluminum-phosphorus master alloy under stirring conditions.

[0065] In the present invention, the time of the modification treatment is preferably 25 to 40 minutes, more preferably 30 to 35 minutes; the method of the modification treatment is preferably static. The present invention can effectively change the unfavorable form of silicon in the aluminum-tin alloy melt through the modification treatment, making it tend to be spherical, thereby improving the strength and plasticity of the aluminum-tin alloy, thereby reducing the probability of cracking of the aluminum-tin alloy during the casting process.

[0066] After obtaining the aluminum-tin alloy melt, the present invention casts the aluminum-tin alloy melt to obtain a low-segregation aluminum-tin alloy round ingot.

[0067] In the present invention, when the diameter of the prepared low-segregation aluminum-tin alloy round ingot is less than 250mm, the present invention preferably directly performs casting; when the diameter of the prepared low-segregation aluminum-tin alloy round ingot is ≥250mm, the present invention preferably adopts an aluminum bottoming process for casting. In the present invention, the purity of the bottoming aluminum used in the aluminum bottoming process is preferably ≥99.7wt.%; the casting length of the aluminum bottoming process is preferably 50mm; the casting speed of the aluminum bottoming process is preferably 40-50mm / min, more preferably 46mm / min; the cooling water of the aluminum bottoming process is preferably 18t / h. The present invention uses aluminum bottoming before casting and then performs casting. In this process, the crystallization temperature of the aluminum-tin alloy melt can be reduced, which is equivalent to reducing the casting speed, reducing the shrinkage of the casting, and preventing cracks.

[0068] In the present invention, the furnace temperature during casting is preferably 740-750° C.; the casting plate temperature during casting is preferably 660-670° C. The present invention can prevent the aluminum-tin alloy melt from cracking due to rapid cooling by controlling the temperature inside the device during casting.

[0069] In the present invention, the liquid level of the aluminum-tin alloy melt is preferably 13-15 mm. The present invention can ensure a higher starting casting temperature by increasing the liquid level of the aluminum-tin alloy melt.

[0070] In the present invention, the starting stage parameters of the casting are preferably: starting length: 50mm, casting speed 50-90mm / min, cooling water: 10-21t / h, more preferably: starting length: 50mm, casting speed 60-80mm / min, cooling water: 12-20t / h, and more preferably: starting length: 50mm, casting speed 70mm / min, cooling water: 15-18t / h. In the present invention, the normal casting stage parameters of the casting are preferably: casting speed: 50-90mm / min, cooling water: 10-21t / h, more preferably: casting speed: 60-80mm / min, cooling water: 12-21t / h, and more preferably: casting speed 70mm / min, cooling water: 15-18t / h. The present invention can control the cooling rate and temperature drop rate of the alloy by controlling the process parameters in the casting process, thereby ensuring that during the casting process, neither excessive internal stress of the alloy will cause cracking due to excessive cooling rate nor deformation due to insufficient strength of the alloy will be caused due to slow cooling rate.

[0071] The preparation method provided by the present invention can make the tin content in the aluminum-tin alloy melt evenly distributed by controlling the smelting process of the aluminum-tin alloy and the order of adding raw materials, thereby reducing the segregation of the tin element in the aluminum-tin alloy and realizing low-cost production of the aluminum-tin alloy billet. By refining the α (Al) solid solution and modifying the second phase, uniform organization and performance are achieved, and at the same time, the cracking problem of the aluminum-tin alloy is solved by combining the bottoming process.

[0072] The operation of the present invention is simple and has considerable economic benefits; it has promotion value for the production of alloys with large component density differences and extremely small solubility; the low-segregation aluminum-tin alloy round ingot product prepared by the present invention has uniform and stable composition, structure and performance, which is beneficial to providing high-quality aluminum-tin alloy round ingot blanks for downstream aluminum-tin alloy bearings and other products, and is beneficial to promoting the progress of casting alloys and downstream aluminum-tin alloy bearing related industries, and has good practicality.

[0073] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0074] Example 1

[0075] A method for preparing a low-segregation aluminum-tin alloy round ingot comprises the following steps:

[0076] (1) mixing an aluminum ingot with a purity of 99.7 wt.%, metallic silicon, an electrolytic copper plate, a nickel plate, a titanium agent and an aluminum-zirconium master alloy, and performing a first smelting, sampling and testing the contents of Fe, Si, Cu, Ni, Ti and Zr in the product, and obtaining a first alloy melt after the content is qualified; the holding temperature of the first smelting is 790° C.;

[0077] (2) adding a tin block and an aluminum-antimony master alloy to the first alloy melt obtained in step (1) and stirring the mixture uniformly, and performing a second smelting. Sampling and testing the contents of Fe, Si, Sn, Sb, Cu, Ni, Zr and Ti in the product, and obtaining a second alloy melt after the contents are qualified; the holding temperature of the second smelting is 765° C., and the holding time of the second smelting is 30 min;

[0078] (3) adding a sodium-free refining agent to the second alloy melt obtained in step (2) for refining, and then skimming off the slag to obtain a third alloy melt; the amount of the refining agent is 3wt.‰ of the second alloy melt; the refining temperature is 760°C, and the refining time is 10 min;

[0079] (4) adding an aluminum-phosphorus master alloy to the third alloy melt obtained in step (3), stirring and then performing a modification treatment to obtain an aluminum-tin alloy melt; the modification treatment time is 30 minutes, and the modification treatment method is standing;

[0080] (5) Casting the aluminum-tin alloy melt obtained in step (4) to obtain a low-segregation aluminum-tin alloy round ingot; the diameter of the low-segregation aluminum-tin alloy round ingot is 120 mm; the furnace temperature during casting is 750° C.; the casting plate temperature is 670° C.; the liquid level of the aluminum-tin alloy melt is 14 mm; the starting stage parameters of the casting are: starting length: 50 mm, casting speed: 54 mm / min, cooling water: 18 t / h; the normal casting stage parameters of the casting are: casting speed: 54 mm / min, cooling water: 19 t / h;

[0081] The composition of the low segregation aluminum-tin alloy round ingot is set to, by mass percentage, Sn: 6.5%, Cu: 1.0%, Ni: 1.0%, Fe: 0.12%, Si: 0.2%, Zr: 0.20%, Ti: 0.1%, Sb: 0.2%, P: 0.06% and the balance Al.

[0082] The low segregation aluminum-tin alloy round ingot obtained in Example 1 was tested. The testing method is: one round ingot was selected at the entrance, center, and end of the casting disk, and the head and tail were sawed respectively. It was found that there was no central crack in the cross section, which shows that the technical solution provided by the present invention can avoid cracks in the round ingot during the casting process.

[0083] The front and rear ends of an aluminum-tin alloy round ingot prepared in Example 1 were sawn to 80 mm at the head and tail, and then a low-magnification slice with a thickness of about 20 mm was cut at the head and tail, and then the composition was tested. The results are shown in Table 1:

[0084] Table 1 Element contents of different parts of the aluminum-tin alloy round ingot prepared in Example 1

[0085] Product-like ingredients Si / wt. Fe / wt. Cu / wt. Ni / wt. Sn / wt. Φ120 inlet end-head 0.183 0.126 0.925 1.060 6.534 Φ120 inlet end-end 0.186 0.123 0.926 1.108 6.282 Φ120 center-head 0.180 0.125 0.932 1.116 6.560 Φ120 center-tail 0.181 0.123 0.924 1.101 6.258 Φ120 terminal-head 0.176 0.126 0.923 1.091 6.245 Φ120 end-tail 0.175 0.125 0.926 1.099 6.524 Range / % 0.011 0.003 0.009 0.056 0.315 Segregation rate / % 6.064 2.693 0.972 5.155 4.925

[0086] It can be seen from Table 1 that the range and segregation rate of the same element in different parts of the aluminum-tin alloy round ingot prepared by the present invention are low, indicating that the aluminum-tin alloy round ingot obtained by the present invention has low segregation.

[0087] Figure 1 This is a physical picture of the low segregation aluminum-tin alloy round ingot prepared in Example 1; Figure 2 This is a physical picture of the cross section of the low segregation aluminum-tin alloy round ingot prepared in Example 1. Figure 1-2 It can be seen that the surface and cross section of the low-segregation aluminum-tin alloy round ingot prepared by the present invention have no central cracks.

[0088] Example 2

[0089] A method for preparing a low-segregation aluminum-tin alloy round ingot comprises the following steps:

[0090] (1) mixing an aluminum ingot with a purity of 99.7 wt.%, metallic silicon, an electrolytic copper plate, a nickel plate, a titanium agent and an aluminum-zirconium master alloy, and performing a first smelting, sampling and testing the contents of Fe, Si, Cu, Ni, Ti and Zr in the product, and obtaining a first alloy melt after the content is qualified; the holding temperature of the first smelting is 790° C.;

[0091] (2) adding a tin block and an aluminum-antimony master alloy to the first alloy melt obtained in step (1) and stirring the mixture uniformly, and performing a second smelting. Sampling and testing the contents of Fe, Si, Sn, Sb, Cu, Ni, Zr and Ti in the product, and obtaining a second alloy melt after the contents are qualified; the holding temperature of the second smelting is 765° C., and the holding time of the second smelting is 30 min;

[0092] (3) adding a sodium-free refining agent to the second alloy melt obtained in step (2) for refining, and then skimming off the slag to obtain a third alloy melt; the amount of the refining agent is 3wt.‰ of the second alloy melt; the refining temperature is 760°C, and the refining time is 10 min;

[0093] (4) adding an aluminum-phosphorus master alloy to the third alloy melt obtained in step (3), stirring and then performing a modification treatment to obtain an aluminum-tin alloy melt; the modification treatment time is 30 minutes, and the modification treatment method is standing;

[0094] (5) Casting the aluminum-tin alloy melt obtained in step (4) to obtain a low-segregation aluminum-tin alloy round ingot; the diameter of the low-segregation aluminum-tin alloy round ingot is 229 mm; the furnace temperature during casting is 750° C.; the casting plate temperature is 670° C.; the liquid level of the aluminum-tin alloy melt is 14 mm; the starting stage parameters of the casting are: starting length: 50 mm, casting speed: 70 mm / min, cooling water: 15 t / h; the normal casting stage parameters of the casting are preferably: casting speed: 90 mm / min, cooling water: 15 t / h;

[0095] The composition of the low segregation aluminum-tin alloy round ingot is set to, by mass percentage, Sn: 6.5%, Cu: 1.0%, Ni: 1.0%, Fe: 0.12%, Si: 0.18%, Zr: 0.20%, Ti: 0.15%, Sb: 0.2%, P: 0.06% and the balance Al.

[0096] The low segregation aluminum-tin alloy round ingot obtained in Example 2 was tested. The testing method was as follows: one round ingot was selected at the entrance, center, and end of the casting disk, and the head and tail were sawed respectively. It was found that there was no central crack in the cross section, indicating that the technical solution provided by the present invention can avoid cracks in the round ingot during the casting process.

[0097] The front and rear ends of an aluminum-tin alloy round ingot prepared in Example 2 were sawn to 80 mm at the head and tail, and then a low-magnification slice with a thickness of about 20 mm was cut at the head and tail, and then the composition was tested. The results are shown in Table 2:

[0098] Table 2 Element contents of different parts of the aluminum-tin alloy round ingot prepared in Example 2

[0099]

[0100] It can be seen from Table 2 that the range and segregation rate of the same element in different parts of the aluminum-tin alloy round ingot prepared by the present invention are low, indicating that the aluminum-tin alloy round ingot obtained by the present invention has low segregation.

[0101] Example 3

[0102] A method for preparing a low-segregation aluminum-tin alloy round ingot comprises the following steps:

[0103] (1) mixing an aluminum ingot with a purity of 99.7 wt.%, metallic silicon, an electrolytic copper plate, a nickel plate, a titanium agent and an aluminum-zirconium master alloy, and performing a first smelting, sampling and testing the contents of Fe, Si, Cu, Ni, Ti and Zr in the product, and obtaining a first alloy melt after the contents are qualified; the holding temperature of the first smelting is 800° C.;

[0104] (2) adding a tin block and an aluminum-antimony master alloy to the first alloy melt obtained in step (1) and stirring the mixture uniformly, and performing a second smelting. Sampling and testing the contents of Fe, Si, Sn, Sb, Cu, Ni, Zr and Ti in the product, and obtaining a second alloy melt after the contents are qualified. The holding temperature of the second smelting is 770° C., and the holding time of the second smelting is 30 min.

[0105] (3) adding a sodium-free refining agent to the second alloy melt obtained in step (2) for refining, and then skimming off the slag to obtain a third alloy melt; the amount of the refining agent is 3wt.‰ of the second alloy melt; the refining temperature is 755°C, and the refining time is 10 min;

[0106] (4) adding an aluminum-phosphorus master alloy to the third alloy melt obtained in step (3), stirring and then performing a modification treatment to obtain an aluminum-tin alloy melt; the modification treatment time is 30 minutes, and the modification treatment method is standing;

[0107] (5) Firstly, aluminum with a purity of 99.7wt.% is used for bottoming, and then the aluminum-tin alloy melt obtained in the step (4) is cast to obtain a low-segregation aluminum-tin alloy round ingot; the diameter of the low-segregation aluminum-tin alloy round ingot is 380mm; the furnace temperature during casting is 750°C; the casting plate temperature is 670°C; the casting length during bottoming is 50mm, the casting speed during bottoming is 46mm / min, and the cooling water is 18t / h; the liquid level of the aluminum-tin alloy melt is 15mm; the starting stage parameters of the casting are: starting length: 50mm, casting speed: 50mm / min, cooling water: 15t / h; the normal casting stage parameters of the casting are preferably: casting speed: 54mm / min, cooling water: 15t / h;

[0108] The composition of the low segregation aluminum-tin alloy round ingot is set to, by mass percentage, Sn: 6.3%, Cu: 1.0%, Ni: 1.0%, Fe: 0.12%, Si: 0.2%, Zr: 0.20%, Ti: 0.20%, Sb: 0.20%, P: 0.06% and the balance Al.

[0109] The low segregation aluminum-tin alloy round ingot obtained in Example 3 was tested. The testing method was as follows: one round ingot was selected at the entrance, center, and end of the casting disk, and the head and tail were sawed separately. It was found that there was no central crack in the cross section, indicating that the technical solution provided by the present invention can avoid cracks in the round ingot during the casting process.

[0110] The front and rear ends of an aluminum-tin alloy round ingot prepared in Example 3 were sawn to 80 mm at the head and tail, and then a low-magnification slice with a thickness of about 20 mm was cut at the head and tail, and then the composition was tested. The results are shown in Table 3:

[0111] Table 3 Element contents of different parts of aluminum-tin alloy round ingots prepared in Example 3

[0112]

[0113] It can be seen from Table 3 that the range and segregation rate of the same element in different parts of the aluminum-tin alloy round ingot prepared by the present invention are low, indicating that the aluminum-tin alloy round ingot obtained by the present invention has low segregation.

[0114] It can be seen from the test data in Tables 1 to 3 that the tin content range in the aluminum-tin alloy round ingot prepared by the present invention is about 0.3-0.375%, and the segregation rate is about 4-6%, indicating that the tin content is very uniform, proving that the technical solution provided by the present invention can make tin uniformly distributed in the aluminum-tin alloy.

[0115] Comparative Example 1

[0116] A method for preparing an aluminum-tin alloy round ingot comprises the following steps:

[0117] (1) Aluminum ingots with a purity of 99.7 wt.%, metallic silicon, electrolytic copper plates and nickel plates are mixed and subjected to a first smelting process. The contents of Fe, Si, Cu and Ni in the products are sampled and tested, and a first alloy melt is obtained after the products are qualified. The holding temperature of the first smelting process is 800° C.;

[0118] (2) adding a tin block to the first alloy melt obtained in step (1) and stirring the mixture evenly, performing a second smelting, sampling and testing the contents of Fe, Si, Sn, Cu and Ni in the product, and obtaining a second alloy melt after the contents are qualified; the holding temperature of the second smelting is 765° C., and the holding time of the second smelting is 30 min;

[0119] (3) adding a sodium-free refining agent to the second alloy melt obtained in step (2) for refining, and then skimming off the slag to obtain an aluminum-tin alloy melt; the amount of the refining agent is 3wt.‰ of the second alloy melt; the refining temperature is 760°C, and the refining time is 10 min;

[0120] (4) Before the aluminum-tin alloy melt enters the chute, the aluminum liquid level in the chute is increased to ensure a high starting casting temperature, and the aluminum-tin alloy melt obtained in the step (3) is cast to obtain an aluminum-tin alloy round ingot; the diameter of the aluminum-tin alloy round ingot is 229 mm; the furnace temperature during the casting is 745° C.; the casting plate temperature is 670° C.; the liquid level of the aluminum-tin alloy melt is 15 mm; the starting stage parameters of the casting are: starting length: 50 mm, casting speed: 70 mm / min, cooling water: 15 t / h; the normal casting stage parameters of the casting are preferably: casting speed: 90 mm / min, cooling water: 15 t / h;

[0121] The composition of the aluminum-tin alloy round ingot is set to be Sn: 7.0%, Cu: 1.0%, Ni: 1.0%, Fe: 0.12%, Si: 0.20% and the balance Al in terms of mass percentage.

[0122] The aluminum-tin alloy round ingot obtained in Comparative Example 1 was tested by selecting one round ingot at the inlet, center, and end of the casting disk, sawing the head and tail respectively, and finding that there was no center crack in the cross section.

[0123] The front and rear ends of the three aluminum-tin alloy round ingots prepared in Comparative Example 1 were sawn off to 80 mm at the head and tail, and then a low-magnification slice with a thickness of about 20 mm was cut at the head and tail, and then the composition was tested. The results are shown in Tables 4 to 6:

[0124] Table 4 Element contents of different parts of aluminum-tin alloy round ingots prepared in comparative example 1

[0125]

[0126] Table 5 Element contents of different parts of aluminum-tin alloy round ingots prepared in comparative example 1

[0127]

[0128] Table 6 Element contents of different parts of aluminum-tin alloy round ingots prepared in comparative example 1

[0129]

[0130] It can be seen from Tables 4 to 6 that when no refinement and modification is performed, the tin content range of the aluminum-tin alloy round ingot prepared in Comparative Example 1 is about 0.963% to 1.855%, which is a large range, and the segregation rate is about 13% to 24%, which is a large segregation rate.

[0131] Comparative Example 2

[0132] A method for preparing an aluminum-tin alloy round ingot comprises the following steps:

[0133] (1) mixing an aluminum ingot with a purity of 99.7 wt.%, metallic silicon, an electrolytic copper plate, a nickel plate, a titanium agent and an aluminum-zirconium master alloy, and performing a first smelting, sampling and testing the contents of Fe, Si, Cu, Ni, Ti and Zr in the product, and obtaining a first alloy melt after the contents are qualified; the holding temperature of the first smelting is 800° C.;

[0134] (2) adding a tin block and an aluminum-antimony master alloy to the first alloy melt obtained in step (1) and stirring the mixture uniformly, and performing a second smelting. Sampling and testing the contents of Fe, Si, Sn, Sb, Cu, Ni, Zr and Ti in the product, and obtaining a second alloy melt after the contents are qualified; the holding temperature of the second smelting is 765° C., and the holding time of the second smelting is 30 min;

[0135] (3) adding a sodium-free refining agent to the second alloy melt obtained in step (2) for refining, and then skimming off the slag to obtain a third alloy melt; the amount of the refining agent is 3wt.‰ of the second alloy melt; the refining temperature is 760°C, and the refining time is 10 min;

[0136] (4) adding an aluminum-phosphorus master alloy to the third alloy melt obtained in step (3), stirring and then performing a modification treatment to obtain an aluminum-tin alloy melt; the modification treatment time is 30 minutes, and the modification treatment method is standing;

[0137] (5) First, aluminum with a purity of 99.7wt.% is used for bottom laying, and then the aluminum-tin alloy melt obtained in the step (4) is cast to obtain an aluminum-tin alloy round ingot; the diameter of the aluminum-tin alloy round ingot is 380mm; the furnace temperature during casting is 750°C; the casting plate temperature is 670°C; the casting length during bottom laying is 50mm, the casting speed during bottom laying is 46mm / min, and the cooling water is 15t / h; the liquid level of the aluminum-tin alloy melt is 14mm; the starting stage parameters of the casting are: starting length: 50mm, casting speed: 105mm / min, cooling water: 12t / h; the normal casting stage parameters of the casting are preferably: casting speed: 120mm / min, cooling water: 12t / h;

[0138] The composition of the aluminum-tin alloy round ingot is set to be, by mass percentage, Sn: 6.5%, Cu: 1.0%, Ni: 1.0%, Fe: 0.12%, Si: 0.18%, Zr: 0.20%, Ti: 0.2%, Sb: 0.20%, P: 0.06% and the balance Al.

[0139] The aluminum-tin alloy round ingot obtained in Comparative Example 2 was tested. The testing method was as follows: one round ingot was selected from the inlet end, the center, and the end of the casting plate, and the head and tail were sawed respectively. The cross-sections all had central cracks, such as Figure 2 As shown. Figure 2 It can be seen that when the casting parameters are not matched, there is a problem of cracking in the production of aluminum-tin alloy round ingots, which shows that the present invention casts an aluminum-tin alloy with uniform composition through appropriate casting conditions, achieves low-cost production of aluminum-tin alloy billets, and solves the problem of cracking of round ingots.

[0140] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-segregation aluminum-tin alloy round ingot, comprising the following components, by mass percentage: Sn: 5.5-7.0%, Cu: 0.7-1.3%, Ni: 0.7-1.3%, Fe≤0.15%, Si: 0.15-0.25%, Zr: 0.15-0.25%, Ti: 0.01-0.20%, Sb: 0.15-0.25%, P: 0.02-0.10% and the balance Al.

2. The low segregation aluminum-tin alloy round ingot according to claim 1, characterized in that: Calculated by mass percentage, it includes the following components: Sn: 6.0-6.5%, Cu: 0.8-1.2%, Ni: 0.8-1.2%, Fe≤0.15%, Si: 0.18-0.23%, Zr: 0.18-0.23%, Ti: 0.08-0.12%, Sb: 0.18-0.23%, P: 0.04-0.08% and the balance Al.

3. The method for preparing the low-segregation aluminum-tin alloy round ingot according to any one of claims 1 to 2, comprising the following steps: (1) melting, refining and modifying the aluminum-tin alloy raw material in sequence to obtain an aluminum-tin alloy melt; (2) Casting the aluminum-tin alloy melt obtained in step (1) to obtain a low-segregation aluminum-tin alloy round ingot.

4. The preparation method according to claim 3, characterized in that: The aluminum-tin alloy raw materials in step (1) include aluminum ingots, metallic silicon, tin blocks, copper plates, nickel plates, titanium agents, aluminum-zirconium master alloys, aluminum-antimony master alloys, aluminum-phosphorus master alloys and refining agents.

5. The preparation method according to claim 3, characterized in that: The steps of preparing the aluminum-tin alloy melt in step (1) are: 1) mixing an aluminum ingot, metallic silicon, a copper plate, a nickel plate, a titanium agent and an aluminum-zirconium master alloy, and performing a first smelting to obtain a first alloy melt; 2) adding a tin block and an aluminum-antimony master alloy to the first alloy melt obtained in step 1) to perform a second smelting to obtain a second alloy melt; 3) adding a refining agent to the second alloy melt obtained in step 2) for refining to obtain a third alloy melt; 4) adding an aluminum-phosphorus master alloy to the third alloy melt obtained in step 3) for modification to obtain an aluminum-tin alloy melt.

6. The preparation method according to claim 5, characterized in that: The insulation temperature of the first smelting in step 1) is 780-830°C.

7. The preparation method according to claim 5, characterized in that: The insulation temperature of the second smelting in the step 2) is 760-770° C., and the insulation time of the second smelting is 20-40 minutes.

8. The preparation method according to claim 5, characterized in that: In the step 3), the refining agent is a sodium-free refining agent, and the amount of the refining agent is 2-3 wt.‰ of the second alloy melt.

9. The preparation method according to claim 3, characterized in that: The parameters of the starting stage of casting in step (2) are: starting length: 50 mm, casting speed 50-90 mm / min, cooling water: 10-21 t / h.

10. The preparation method according to claim 3, characterized in that: The normal casting phase parameters of the casting in step (2) are: casting speed: 50-90 mm / min, cooling water: 10-21 t / h.

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