Smelting and die-casting process of high-toughness die-casting aluminum-silicon alloy and high-toughness die-casting aluminum-silicon alloy

Abstract

The invention relates to the technical field of alloy smelting, in particular to a smelting and die-casting process of a high-toughness die-casting aluminum-silicon alloy and the high-toughness die-casting aluminum-silicon alloy. The smelting and die-casting technology of the high-toughness die-casting aluminum-silicon alloy comprises the following steps that preparation is conducted before smelting; smelting process control; refining and purifying; testing and adjusting components; and die-casting. Wherein the smelting comprises the following steps: firstly adding pure Al, pure Zn and AlSi20, heating and melting, then heating, adding AlMn10, AlCu10, AlTi10 and Al5V, melting, stirring, cooling, adding pure Mg, melting and stirring; raising the temperature, adding a refining agent, turning and stirring, and slagging off; and finally, adding AlSr10, AlLa30 and AlCe10, melting, and stirring. According to the method, by means of segmented feeding and smelting at different temperatures and die-casting process parameter control, the problem that the mechanical property of the high-toughness die-casting aluminum-silicon alloy cannot be exerted due to inaccurate component control in the smelting process and non-ideal cooling speed in the die-casting process is solved, and the prepared aluminum-silicon alloy has excellent comprehensive performance.

Description

Technical Field

[0001] The present application relates to the technical field of alloy smelting, and in particular to a smelting and die-casting process of a high-strength and toughness die-cast aluminum-silicon alloy and a high-strength and toughness die-cast aluminum-silicon alloy. Background Art

[0002] Aluminum-silicon alloy is a typical eutectic alloy with a simple phase diagram, no intermediate compounds, good casting performance, high specific strength, and low price. Usually, the silicon content of aluminum-silicon alloy is between 5% and 15%, and the aluminum content is between 80% and 95%. In order to ensure the mechanical properties of the alloy while ensuring the casting process performance of the alloy, other alloying elements are generally added to the alloy, so that the above alloying elements can be dissolved into the matrix or form a strengthening phase when the melt solidifies, thereby improving the mechanical properties of the casting.

[0003] However, in the actual smelting process, the amount of added elements, the degree of alloying, the mutual influence between elements during the melting process, and the smelting process parameters will have a significant impact on the quality of the alloy. For example, the Sr element is not added to the conventional die-casting Al-Si alloy. On the one hand, the Sr element is easy to burn and bring about oxidation slag. On the other hand, the addition of Sr will increase the gas content of the melt, resulting in low quality of the aluminum ingot.

[0004] In addition to the melt quality problems caused by the above-mentioned smelting process, during the die-casting process, due to the burnout of alloy elements, the mismatch between the casting wall thickness and the die-casting parameters resulting in an unsatisfactory cooling rate of the casting, the alloy elements may fail to fully form a second phase or dissolve into the matrix structure to strengthen the casting, resulting in the inability to fully exert the mechanical properties of the high-strength and toughness die-cast aluminum-silicon alloy. Summary of the invention

[0005] Based on this, it is necessary to provide a smelting and die-casting process of high-strength and toughness die-cast aluminum-silicon alloy and a high-strength and toughness die-cast aluminum-silicon alloy to solve the problem that the mechanical properties of high-strength and toughness die-cast aluminum-silicon alloy cannot be exerted due to inaccurate composition control in the existing smelting process and unsatisfactory cooling rate in the die-casting process. This application reduces the burnout of alloy elements by adding materials and smelting in stages at different temperatures, and at the same time, through the control of process parameters, ensures that under the die-casting cooling rate conditions, the alloy elements can be fully dissolved into the matrix to form a fine strengthening phase, thereby improving the comprehensive performance of the alloy.

[0006] In the first aspect of the present application, a smelting and die-casting process for a high-strength and toughness die-cast aluminum-silicon alloy is provided, comprising the following steps: S1: material preparation; S2: smelting; S3: refining and purification; S4: component testing and adjustment; S5: die-casting, cooling, and post-processing to obtain a high-strength and toughness die-cast aluminum-silicon alloy.

[0007] The smelting comprises the following steps:

[0008] S2-1: Add pure Al, pure Zn and AlSi20 into a smelting furnace and heat up to melt them.

[0009] S2-2: Raise the temperature to 740-760°C, add AlMn10, AlCu10, AlTi10, and Al5V, ​​keep warm until completely melted, and stir.

[0010] S2-3: Cool down to 680℃-690℃, add pure Mg, keep warm until melted, and stir; then heat up to 720℃-730℃, add refining agent, stir, and skim off the slag.

[0011] S2-4: Add AlSr10, AlLa30, AlCe10, keep warm until completely melted, and stir to obtain a molten alloy.

[0012] In some embodiments, the material preparation includes: raw material preparation, smelting equipment inspection, and smelting tools and mold preparation.

[0013] In some embodiments, in S2-1, the purity of the pure Al is ≥99.85%; the purity of the pure Zn is ≥99.9%; and the temperature of the heating and melting is 700°C-720°C.

[0014] In some embodiments, in S2-2, S2-3, and S2-4, the stirring time is 5 min to 10 min.

[0015] In some embodiments, in S2-3, the purity of the pure Mg is ≥99.9%; and the amount of the refining agent added is 0.9%-1.1% of the total mass of the melt in step S3.

[0016] In some embodiments, S3: the specific method of refining and purification is: adding a refining agent to the smelted alloy melt, refining, letting it stand, and removing scum to obtain a purified melt.

[0017] In some embodiments, the refining agent is a three-in-one refining agent, and the amount of the refining agent added is 0.9%-1.1% of the mass of the smelted alloy melt; the number of refining times is ≥2 times.

[0018] In some embodiments, after the S4 component is tested and adjusted, the purified melt is also transferred and kept warm.

[0019] In some embodiments, during S5 die-casting, the purified melt temperature is controlled at 690°C-700°C for die-casting, and the die-casting parameters are: mold temperature 180°C-250°C, low speed 0.20m / s-0.25m / s, high speed 2.7m / s-3.4m / s, high speed position 250mm-260mm, casting pressure 80MPa-90MPa, boost position 275mm-285mm, vacuum degree 40mbar-45mbar, and mold retention time 8s-12s.

[0020] A second aspect of the present application provides a high-strength and toughness die-cast aluminum-silicon alloy, which is produced by the smelting and die-casting process of the high-strength and toughness die-cast aluminum-silicon alloy of the first aspect mentioned above.

[0021] The present application fully considers the melting point and burning tolerance of pure metals and intermediate alloys, and reduces the burning of actual alloy elements by adding materials and smelting in stages at different temperatures, thereby ensuring a match between actual and designed values.

[0022] Furthermore, the present application takes the target casting wall thickness as a basis and controls the die-casting process parameters to ensure that under the die-casting cooling rate conditions, the alloy elements can fully dissolve into the matrix and form fine strengthening phases, thereby giving full play to the performance of the high-strength and toughness die-cast aluminum-silicon alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a melting and die-casting process for a high-strength and toughness die-cast aluminum-silicon alloy according to one embodiment. DETAILED DESCRIPTION

[0024] References to embodiments of the present application will now be provided in detail, one or more embodiments of which are described below. Each embodiment is provided as an explanation rather than a limitation of the present application. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present application without departing from the scope or spirit of the present application. For example, a feature described or described as part of one embodiment may be used in another embodiment to produce a further embodiment.

[0025] Therefore, it is intended that the present application covers such modifications and variations that fall within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present application are disclosed in or are apparent from the following detailed description. It will be appreciated by those of ordinary skill in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the present application.

[0026] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0027] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0028] In this article, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 100~150 ℃ means that the units of the left endpoint "100" and the right endpoint "150" are both ℃ (Celsius).

[0029] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0030] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0031] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, mentioning that the method may also include step (c) means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0032] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0033] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0034] In view of the problems that the composition of existing alloys is not accurately controlled during the smelting process and the cooling rate during the die-casting process is not ideal, resulting in unsatisfactory mechanical properties of the alloys, the present application proposes a smelting and die-casting process for high-strength and toughness die-cast aluminum-silicon alloy and a high-strength and toughness die-cast aluminum-silicon alloy to solve the above-mentioned technical problems existing in traditional smelting and die-casting processes.

[0035] A melting and die-casting process for high-strength and tough die-cast aluminum-silicon alloy, such as Figure 1 As shown, the following steps are included:

[0036] S1: material preparation; S2: smelting; S3: refining and purification; S4: composition testing and adjustment; S5: die casting, cooling, and post-processing to obtain high-strength and toughness die-cast aluminum silicon alloy.

[0037] In some embodiments, the material preparation includes: S1-1 raw material preparation; S1-2 smelting equipment inspection; S1-3 smelting tools and mold preparation.

[0038] In some embodiments, S1-1 raw material preparation is specifically as follows: prepare raw materials for preparing high-strength and toughness die-casting aluminum-silicon alloy, including: pure Al, pure Mg, pure Zn; intermediate alloys: AlSi20, AlMn10, AlCu10, AlTi10, Al5V, ​​AlSr10, AlLa30, AlCe10; since intermediate alloys often contain impurity elements Fe, Na, and B, the Fe content, Na content, and B content should be strictly tested and controlled when selecting the intermediate alloy to meet the component requirements of the high-strength and toughness die-casting aluminum-silicon alloy.

[0039] In some embodiments, S1-2 smelting equipment inspection specifically includes: checking whether the smelting furnace, refining equipment, protective gas system, etc. are intact to ensure that there are no safety hazards in the equipment; checking the furnace body, whether the furnace wall and furnace nozzle are in good condition, the slag is cleaned, and the furnace body rotation mechanism is normal; and for metal low-iron alloys, special smelting equipment is required to melt the alloy ingots or wash the furnace.

[0040] In some embodiments, S1-3 tool and mold preparation includes: preparing the required smelting tools, slag skimming tools, refining agents, temperature measuring instruments, etc., and ensuring that the die-casting mold has been preheated to an appropriate temperature. The tools used in the melting process must be cleaned and painted.

[0041] It is understandable that when preparing the raw materials in step S1-1, the ingredients can be prepared according to the designed alloy composition, and the large alloy ingots can be cut into small pieces to facilitate subsequent melting and feeding, while ensuring that the quality of all aluminum alloy raw materials meets the standards and the surface is clean and free of oil, moisture and other impurities.

[0042] In some embodiments, smelting includes the following steps:

[0043] S2-1: Add pure Al, pure Zn and AlSi20 into a smelting furnace and heat up to melt them.

[0044] S2-2: Raise the temperature to 740-760°C, add AlMn10, AlCu10, AlTi10, and Al5V, ​​keep warm until completely melted, and stir.

[0045] S2-3: Cool down to 680℃-690℃, add pure Mg, keep warm until melted, and stir; then heat up to 720℃-730℃, add refining agent, stir, and skim off the slag.

[0046] S2-4: Add AlSr10, AlLa30, AlCe10, keep warm until completely melted, and stir to obtain a molten alloy.

[0047] In some embodiments, in S2-1, the purity of the pure Al is ≥99.85%; the purity of the pure Zn is ≥99.9%; the temperature of the heating and melting is 700°C-720°C; including but not limited to 700°C, 705°C, 710°C, 715°C, and 720°C.

[0048] In some embodiments, step S2-1 further includes placing the intermediate alloy other than AlSi20 at the furnace side or baking it in an oven at 200° C. for later use.

[0049] In some embodiments, in S2-2, S2-3, and S2-4, the stirring time is 5 min-10 min, including but not limited to 5 min, 6 min, 7 min, 8 min, 9 min, and 10 min.

[0050] In some embodiments, in S2-2, S2-3, and S2-4, the stirring is steady stirring in one direction.

[0051] In some embodiments, in S2-3, pure Mg is added and kept warm until it is melted, which is to add pure Mg, press the pure Mg below the liquid surface using a bell jar, and keep warm until it is completely melted.

[0052] In some embodiments, in S2-4, AlSr10, AlLa30, and AlCe10 are added and kept warm until they are completely melted. The intermediate alloys of AlSr10, AlLa30, and AlCe10 are added, pressed below the liquid surface using a bell jar, and kept warm until they are completely melted.

[0053] In some embodiments, in S2-3, the purity of the pure Mg is ≥99.9%; the amount of the refining agent added is 0.9%-1.1% of the total mass of the melt in step S3, including but not limited to 0.9%, 1.0%, and 1.1%.

[0054] During the entire smelting process of the present application, argon or other protective gases need to be continuously introduced to prevent the alloy from being oxidized.

[0055] It can be understood that, during the smelting process, the present application significantly reduces the high-temperature insulation time of the melt by adding intermediate alloys at different temperature stages, thereby effectively reducing the burnout of alloy elements, and further effectively controlling the smelting composition.

[0056] In some embodiments, argon or other protective gases are continuously introduced throughout the melting process to prevent the alloy from oxidation.

[0057] In some embodiments, S3: the specific method of refining and purification is: adding a refining agent to the smelted alloy melt, refining, letting it stand, and removing scum to obtain a purified melt.

[0058] In some embodiments, the refining agent is a three-in-one refining agent. The amount of the refining agent added is 0.9%-1.1% of the mass of the smelted alloy melt, including but not limited to 0.9%, 1.0%, and 1.1%; the number of refining is ≥2 times.

[0059] It is understood that impurities and gases are removed through refining.

[0060] In some embodiments, the post-refining standing and dross removal is to stand the alloy liquid after refining to allow the dross to float, and then carefully skim off the surface dross to obtain a purified melt.

[0061] In some embodiments, the refining agent is a 45% NaCl + 55% KCl eutectic mixed salt, which has a good effect on Al 2 O 3 Inclusions and oxide films have good wettability and can spread well on the melt surface.

[0062] In some embodiments, S4: performing composition testing and adjustment specifically includes: determining the alloy components in the purified melt, and making adjustments according to the content of each component in the alloy involved.

[0063] It is understood that the present application needs to control the chemical composition of the solidified material in the metal mold within a preset range, and the composition should be tested according to the test process, standard sample selection and calibration of ASTM E34, ASTM E406, ASTM E607, ASTM E1251, GB / T7999 or other equivalent standards. The test can be performed by spectroscopy.

[0064] In some embodiments, after the S4 component is tested and adjusted, the purified melt is also transferred and kept warm.

[0065] Preferably, the specific process of transfer and insulation is: transferring the refined alloy liquid to an insulation furnace, keeping the liquid surface clean to avoid secondary contamination; wherein, maintaining the alloy liquid temperature at 690°C-700°C to prepare for die casting.

[0066] In some embodiments, during S5 die-casting, a die-casting machine of appropriate tonnage is selected according to the size of parts and the demand for alloy liquid, and the temperature of the purified melt is controlled at 690°C-700°C for die-casting. The die-casting parameters are: mold temperature 180°C-250°C, low speed 0.20m / s-0.25m / s, high speed 2.7m / s-3.4m / s, high speed position 250mm-260mm, casting pressure 80MPa-90MPa, boost position 275mm-285mm, vacuum degree 40mbar-45mbar, and mold retention time 8s-12s. The temperature of the mold includes but is not limited to 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, and 250°C; the low speed includes but is not limited to 0.2m / s, 0.21m / s, 0.22m / s, 0.23m / s, 0.24m / s, and 0.25m / s; the high speed includes but is not limited to 2.7m / s, 2.8m / s, 2.9m / s, 3.0m / s, 3.1m / s, 3.2m / s, 3.3m / s, and 3.4m / s; the high speed position includes but is not limited to 250mm, 252mm, 2 54mm, 256mm, 258mm, 260mm; casting pressure includes but is not limited to 80MPa, 82MPa, 84MPa, 86MPa, 88MPa, 90MPa; boost position includes but is not limited to 275mm, 277mm, 279mm, 280mm, 282mm, 284mm, 285mm; vacuum degree includes but is not limited to 40mbar, 41mbar, 42mbar, 43mbar, 44mbar, 45mbar; mold retention time includes but is not limited to 8s, 9s, 10s, 11s, 12s.

[0067] It is understandable that the present application can ensure rapid filling of the alloy liquid without forming air entrapment by adjusting the control of low and high speed injection speed and pressure according to the size, shape and alloy properties of the casting.

[0068] In some embodiments, the die casting is followed by cooling and post-processing.

[0069] In some embodiments, the cooling and post-processing process is specifically as follows: cooling the die-cast casting, opening the mold, and finally cleaning and heat treating.

[0070] It is understandable that the cooling time is set appropriately according to the thickness of the casting and the thermal conductivity of the aluminum alloy. This application does not limit the cooling time, and any cooling time that can achieve the effect of this application is within the protection scope of this application.

[0071] It is understandable that in the present application, it is necessary to ensure that the casting is fully solidified before opening the mold to avoid deformation or cracking.

[0072] It is understood that cleaning is to cut off the gate, overflow system, etc. of the casting. When it is necessary to improve the mechanical properties of the casting, further solution heat treatment and effective heat treatment can be performed. The present application does not limit the specific process of solution heat treatment and effective heat treatment, and any process that can achieve the purpose of the present application is within the scope of protection of the present application.

[0073] A second aspect of the present application provides a high-strength and toughness die-cast aluminum-silicon alloy, which is produced by the smelting and die-casting process of the high-strength and toughness die-cast aluminum-silicon alloy of the first aspect mentioned above.

[0074] It can be understood that, as an example, the high-strength and toughness die-cast aluminum-silicon alloy of the embodiments given in the present application has the same composition, which includes, by mass percentage, Si 8.4%, Mg 0.23%, Mn 0.6%, Cu 0.10%, Ti 0.15%, V 0.02%, Zn 0.25%, Sr 0.03%, Fe <0.1%, Na <0.004, B <0.002, La 0.01%, Ce 0.01%, and the balance is Al.

[0075] The following are specific embodiments.

[0076] Example 1

[0077] A high-strength and toughness die-cast aluminum-silicon alloy, the smelting and die-casting process of which comprises the following steps:

[0078] (1) Preparation before smelting

[0079] S1-1: Raw material preparation

[0080] The raw materials used to prepare the alloy include pure Al (purity ≥ 99.85%), pure Mg (purity ≥ 99.9%), and pure Zn (purity ≥ 99.9%); intermediate alloys: AlSi20, AlMn10, AlCu10, AlTi10, Al5V, ​​AlSr10, AlLa30, and AlCe10; since intermediate alloys often contain impurity elements Fe, Na, and B, the contents of Fe, Na, and B should be strictly tested and controlled when selecting intermediate alloys to meet the requirements of the composition of high-strength and toughness die-casting aluminum-silicon alloys.

[0081] S1-2: Melting equipment inspection: Check whether the melting furnace, refining equipment, protective gas system, etc. are in good condition to ensure that there are no safety hazards in the equipment; check the furnace body, furnace wall, and furnace nozzle to see if they are in good condition, the slag is clean, and the furnace body rotation mechanism is normal; and for low-iron alloys, special melting equipment is required to melt the alloy ingots.

[0082] S1-3: Tool and mold preparation: Prepare the required melting tools, slag skimming tools, refining agents, temperature measuring instruments, etc., and ensure that the die-casting mold has been preheated to the appropriate temperature. The tools used in the melting process must be cleaned and painted.

[0083] (2) Melting

[0084] S2-1: Add pure Al, Zn and AlSi20 into the melting furnace, raise the temperature to 700℃ and melt all of them; place the remaining alloy beside the furnace for standby use.

[0085] S2-2: Raise the temperature to 750°C, add AlMn10, AlCu10, AlTi10, and Al5V master alloys, maintain the temperature until the master alloy is completely melted, and stir steadily in one direction for 8 minutes after complete melting.

[0086] S2-3: Cool down to 685°C, add pure Mg, use a bell jar to press the pure Mg below the liquid surface, and stir steadily in one direction for 8 minutes after it is completely melted.

[0087] S2-4: Raise the temperature to 725℃, add refining agent, stir and skim.

[0088] S2-5: Add AlSr10, AlLa30, AlCe10 master alloys, press them below the liquid surface using a bell jar, and stir them steadily in one direction for 8 minutes after they are completely melted.

[0089] (3) Refining and purification

[0090] S3-1: Add 1% of the total mass of the melt into the molten alloy three-in-one refining agent, and perform two refining operations to remove impurities and gases.

[0091] S3-2: After refining, the alloy liquid is allowed to stand to allow the slag to float up, and then the surface slag is carefully skimmed off to obtain a purified melt.

[0092] (4) Ingredient testing and adjustment

[0093] Test and adjust the composition of each element to make it meet the designed ratio requirements of the alloy elements.

[0094] The purified melt with adjusted composition is transferred to a holding furnace to keep the liquid surface clean and avoid secondary contamination; wherein, holding is to keep the alloy liquid temperature at 695°C in preparation for die casting.

[0095] (5) Die casting, cooling, mold opening, and cleaning to obtain high-strength and toughness die-cast aluminum-silicon alloy castings.

[0096] The die-casting parameters of the die-casting machine are set, and the die-casting parameters are shown in Table 1. After the mold is preheated to the mold temperature, the alloy melt is added, and the punch is pressed in at a low speed. When the punch moves to the high-speed position, it starts to be pressed in at a high speed. The die-casting machine is vacuumed to 40mbar, and the punch continues to move. When the punch moves to the boost position, the casting pressure is set to 80MPa, the mold is retained, and the die-casting is completed. After the die-casting casting is cooled, the mold is opened, and then it is cleaned to obtain a high-strength and toughness die-cast aluminum-silicon alloy casting.

[0097] Example 2

[0098] A high-strength and high-toughness die-cast aluminum-silicon alloy, comprising the same components as those in Example 1.

[0099] The smelting and die-casting process of the above-mentioned high-strength and toughness die-casting aluminum-silicon alloy is basically the same as that of Example 1, except for the die-casting parameter setting. In this embodiment, the die-casting parameters are shown in Table 1.

[0100] Die-casting process: After the mold is preheated to the mold temperature, the molten metal is added and the punch is pressed in at a low speed. When the punch moves to the high-speed position, it starts to be pressed in at a high speed. The die-casting machine is vacuumed to 40mbar, and the punch continues to move. When the punch reaches the boost position, the casting pressure is set to 80MPa, the mold is retained, and the die-casting is completed.

[0101] Example 3

[0102] A high-strength and high-toughness die-cast aluminum-silicon alloy, comprising the same components as those in Example 1.

[0103] The smelting and die-casting process of the above-mentioned high-strength and toughness die-casting aluminum-silicon alloy is basically the same as that of Example 1, except for the die-casting parameter setting. In this embodiment, the die-casting parameters are shown in Table 1.

[0104] Die-casting process: After the mold is preheated to the mold temperature, the molten metal is added and the punch is pressed in at a low speed. When the punch moves to the high-speed position, it starts to be pressed in at a high speed. The die-casting machine is vacuumed to 40mbar, and the punch continues to move. When the punch reaches the boost position, the casting pressure is set to 80MPa, the mold is retained, and the die-casting is completed.

[0105] Example 4

[0106] A high-strength and high-toughness die-cast aluminum-silicon alloy, comprising the same components as those in Example 1.

[0107] The smelting and die-casting process of the above-mentioned high-strength and toughness die-casting aluminum-silicon alloy is basically the same as that of Example 1, except for the die-casting parameter setting. In this embodiment, the die-casting parameters are shown in Table 1.

[0108] Die-casting process: After the mold is preheated to the mold temperature, the molten metal is added and the punch is pressed in at a low speed. When the punch moves to the high-speed position, it starts to be pressed in at a high speed. The die-casting machine is vacuumed to 40mbar, and the punch continues to move. When the punch reaches the boost position, the casting pressure is set to 80MPa, the mold is retained, and the die-casting is completed.

[0109] Table 1 Die casting parameters of Examples 1-4

[0110]

[0111] Example 5

[0112] A high-strength and toughness die-cast aluminum-silicon alloy, the smelting and die-casting process of which comprises the following steps:

[0113] (1) Preparation before smelting

[0114] S1-1: Raw material preparation

[0115] The raw materials used to prepare the alloy include pure Al (purity ≥ 99.85%), pure Mg (purity ≥ 99.9%), and pure Zn (purity ≥ 99.9%); intermediate alloys: AlSi20, AlMn10, AlCu10, AlTi10, Al5V, ​​AlSr10, AlLa30, and AlCe10; since intermediate alloys often contain impurity elements Fe, Na, and B, the contents of Fe, Na, and B should be strictly tested and controlled when selecting intermediate alloys to meet the requirements of the composition of high-strength and toughness die-casting aluminum-silicon alloys.

[0116] S1-2: Melting equipment inspection: Check whether the melting furnace, refining equipment, protective gas system, etc. are in good condition to ensure that there are no safety hazards in the equipment; check the furnace body, furnace wall, and furnace nozzle to see if they are in good condition, the slag is clean, and the furnace body rotation mechanism is normal; and for low-iron alloys, special melting equipment is required to melt the alloy ingots.

[0117] S1-3: Tool and mold preparation: Prepare the required melting tools, slag skimming tools, refining agents, temperature measuring instruments, etc., and ensure that the die-casting mold has been preheated to the appropriate temperature. The tools used in the melting process must be cleaned and painted.

[0118] (2) Melting

[0119] S2-1: Add pure Al, Zn and AlSi20 into the melting furnace, raise the temperature to 700℃ and melt all of them; place the remaining alloy beside the furnace for standby use.

[0120] S2-2: Raise the temperature to 740°C, add AlMn10, AlCu10, AlTi10, and Al5V master alloys, maintain the temperature until the master alloy is completely melted, and stir steadily in one direction for 10 minutes after it is completely melted.

[0121] S2-3: Cool down to 680°C, add pure Mg, use a bell jar to press the pure Mg below the liquid surface, and stir steadily in one direction for 10 minutes after it is completely melted.

[0122] S2-4: Raise the temperature to 720℃, add refining agent, stir and skim.

[0123] S2-5: Add AlSr10, AlLa30, AlCe10 master alloys, press them below the liquid surface using a bell jar, and stir them steadily in one direction for 10 minutes after they are completely melted.

[0124] (3) Refining and purification

[0125] S3-1: adding 0.9% of the total mass of the melt to the molten alloy three-in-one refining agent, and performing two refining operations to remove impurities and gases;

[0126] S3-2: After refining, the alloy liquid is allowed to stand to allow the slag to float up, and then the surface slag is carefully skimmed off to obtain a purified melt.

[0127] (4) Ingredient testing and adjustment

[0128] The components of each element in the purified melt are tested and adjusted to meet the designed ratio requirements of the alloy elements.

[0129] The purified melt after adjusting the composition is transferred to a holding furnace to keep the liquid surface clean and avoid secondary contamination; wherein, holding is to keep the alloy liquid temperature at 690°C in preparation for die casting.

[0130] (5) Die casting, cooling, mold opening, and cleaning to obtain high-strength and toughness die-cast aluminum-silicon alloy castings.

[0131] The die casting parameters are set as shown in Table 1. After the mold is preheated to a mold temperature of 180°C, the alloy melt is added, and the punch is pressed in at a low speed of 0.2 m / s. When the punch moves to the high-speed position of 250 mm, it starts to be pressed in at a high speed of 2.7 m / s. The die casting machine is evacuated to 40 mbar, and the punch continues to move. When the punch moves to the boost position, the casting pressure is set to 90 MPa, the mold is retained for 8 seconds, and the die casting is completed. After the die-casting casting is cooled, the mold is opened, and then it is cleaned to obtain a high-strength and tough die-cast aluminum-silicon alloy casting.

[0132] Example 6

[0133] A high-strength and toughness die-cast aluminum-silicon alloy, the smelting and die-casting process of which comprises the following steps:

[0134] (1) Preparation before smelting

[0135] S1-1: Raw material preparation

[0136] The raw materials used to prepare the alloy include pure Al (purity ≥ 99.85%), pure Mg (purity ≥ 99.9%), and pure Zn (purity ≥ 99.9%); intermediate alloys: AlSi20, AlMn10, AlCu10, AlTi10, Al5V, ​​AlSr10, AlLa30, and AlCe10; since intermediate alloys often contain impurity elements Fe, Na, and B, the contents of Fe, Na, and B should be strictly tested and controlled when selecting intermediate alloys to meet the requirements of the composition of high-strength and toughness die-casting aluminum-silicon alloys.

[0137] S1-2: Melting equipment inspection: Check whether the melting furnace, refining equipment, protective gas system, etc. are in good condition to ensure that there are no safety hazards in the equipment; check the furnace body, furnace wall, and furnace nozzle to see if they are in good condition, the slag is clean, and the furnace body rotation mechanism is normal; and for low-iron alloys, special melting equipment is required to melt the alloy ingots.

[0138] S1-3: Tool and mold preparation: Prepare the required melting tools, slag skimming tools, refining agents, temperature measuring instruments, etc., and ensure that the die-casting mold has been preheated to the appropriate temperature. The tools used in the melting process must be cleaned and painted.

[0139] (2) Melting

[0140] S2-1: Add pure Al, Zn and AlSi20 into the melting furnace, raise the temperature to 700℃ and melt all of them; place the remaining alloy beside the furnace for standby use.

[0141] S2-2: Raise the temperature to 760°C, add AlMn10, AlCu10, AlTi10, and Al5V master alloys, maintain the temperature until the master alloy is completely melted, and stir steadily in one direction for 5 minutes after it is completely melted.

[0142] S2-3: Cool down to 690°C, add pure Mg, use a bell jar to press the pure Mg below the liquid surface, and stir steadily in one direction for 5 minutes after it is completely melted.

[0143] S2-4: Raise the temperature to 730°C, add refining agent, stir and skim.

[0144] S2-5: Add AlSr10, AlLa30, AlCe10 master alloys, press them below the liquid surface using a bell jar, and stir them steadily in one direction for 5 minutes after they are completely melted.

[0145] (3) Refining and purification

[0146] S3-1: adding 1% of the total mass of the melt to the molten alloy, a three-in-one refining agent, and performing two refining operations to remove impurities and gases;

[0147] S3-2: After refining, the alloy liquid is allowed to stand to allow the slag to float up, and then the surface slag is carefully skimmed off to obtain a purified melt.

[0148] (4) Ingredient testing and adjustment

[0149] The components of each element of the purified melt are tested and adjusted to meet the requirements of the designed ratio of alloy elements.

[0150] The purified melt with adjusted composition is transferred to a holding furnace to keep the liquid surface clean and avoid secondary contamination; wherein, holding is to keep the alloy liquid temperature at 700°C in preparation for die casting.

[0151] (5) Die casting, cooling, mold opening, and cleaning to obtain high-strength and toughness die-cast aluminum-silicon alloy castings.

[0152] The die casting parameters are set as shown in Table 1. After the mold is preheated to the mold temperature, the alloy melt is added, and the punch is pressed in at a low speed of 0.25 m / s. When the punch moves to the high-speed position of 255 mm, it starts to be pressed in at a high speed of 3.4 m / s. The die casting machine is vacuumed to 40 mbar, and the punch continues to move. When the punch moves to the boost position of 285 mm, the casting pressure is set to 85 MPa, and the mold is retained for 12 seconds to complete the die casting. After the die-casting casting is cooled, the mold is opened, and then it is cleaned to obtain a high-strength and toughness die-cast aluminum-silicon alloy casting.

[0153] Comparative Example 1

[0154] It is basically the same as Example 3, except that the temperature of the melt during die casting is changed. In this comparative example, the temperature of the melt during die casting is 670°C.

[0155] Comparative Example 2

[0156] It is basically the same as Example 3, except that the temperature of the melt during die casting is changed. In this comparative example, the temperature of the melt during die casting is 730°C.

[0157] Comparative Example 3

[0158] It is basically the same as Example 3, except that the temperature of the mold during die casting is changed. In this comparative example, the temperature of the mold is 170°C.

[0159] Comparative Example 4

[0160] It is basically the same as Example 3, except that the high speed during die casting is changed. In this comparative example, the high speed is 2.5 m / s.

[0161] Comparative Example 5

[0162] It is basically the same as Example 3, except that the high speed during die casting is changed. In this comparative example, the high speed is 3.5 m / s.

[0163] Comparative Example 6

[0164] It is basically the same as Example 3, except that "cooling to 685°C" in S2-3 is changed to "cooling to 710°C". The experiment found that Mg will burn at high temperature at this time, and the burning rate of magnesium will increase significantly.

[0165] Comparative Example 7

[0166] It is basically the same as Example 3, except that the step S2-5 in the smelting is merged into S2-2. That is, the smelting steps of this comparative example are:

[0167] S2-1: Add pure Al, Zn and AlSi20 into the melting furnace, raise the temperature to 700℃ and melt all of them; place the remaining alloy beside the furnace for standby use.

[0168] S2-2: Raise the temperature to 760°C, add AlMn10, AlCu10, AlTi10, Al5V, ​​pure Mg, AlSr10, AlLa30, AlCe10, maintain the temperature until the intermediate alloy is completely melted, and stir steadily in one direction for 5 minutes after complete melting.

[0169] Test example:

[0170] (1) Alloy mechanical properties test

[0171] The aluminum-silicon alloys prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were subjected to mechanical property tests, and the test results are shown in Table 2 below.

[0172] Table 2 Mechanical properties test of embodiments and comparative examples

[0173]

[0174] As can be seen from Table 2 above, the alloy prepared in the present application has better overall mechanical properties by controlling the smelting and die-casting processes, especially the melt temperature, mold temperature and speed at high speed during die-casting.

[0175] (2) Determination of the burning rate of each element in the alloy

[0176] The content of each element in the alloy before and after smelting was determined by spectral method (the burn-in rate of the elements not given had no significant difference). The spectral test results of Example 3 and Comparative Example 7 were compared respectively to obtain the burn-in rate of each element in the alloy of Example 3 and Comparative Example 7. The results are shown in Table 3.

[0177] Table 3: Burning rate of elements in the alloys of Example 3 and Comparative Example 7

[0178]

[0179] It can be seen from Table 3 that the burn-out rate of each element in the alloy of Comparative Example 7 is greater than that of Example 3, indicating that the burn-out rate of the corresponding elements in the alloy obtained by the present application is significantly reduced through the improvement of the process.

[0180] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0181] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A smelting and die-casting process for high-strength and toughness die-casting aluminum-silicon alloy, characterized in that: The steps include: S1: Prepare materials; S2: smelting; S3: Refining and Purification; S4: ingredient testing and adjustment; S5: die casting, cooling and post-treatment to obtain high-strength and toughness die-cast aluminum-silicon alloy; The smelting comprises the following steps: S2-1: Add pure Al, pure Zn and AlSi20 into a smelting furnace and heat them up to melt; S2-2: Raise the temperature to 740-760°C, add AlMn10, AlCu10, AlTi10, and Al5V, ​​keep warm until completely melted, and stir; S2-3: Cool down to 680℃-690℃, add pure Mg, keep warm until melted, stir; then heat up to 720℃-730℃, add refining agent, stir, and skim off the slag; S2-4: Add AlSr10, AlLa30, AlCe10, keep warm until completely melted, and stir to obtain a molten alloy.

2. The smelting and die-casting process of high-strength and toughness die-casting aluminum-silicon alloy according to claim 1 is characterized in that: The material preparation includes: raw material preparation, smelting equipment inspection and smelting tools and mold preparation.

3. The smelting and die-casting process of high-strength and toughness die-casting aluminum-silicon alloy according to claim 1, characterized in that: In S2-1, the purity of the pure Al is ≥99.85%; the purity of the pure Zn is ≥99.9%; and the temperature of the heating and melting is 700°C-720°C.

4. The smelting and die-casting process of high-strength and toughness die-casting aluminum-silicon alloy according to claim 1, characterized in that: In S2-2, S2-3 and S2-4, the stirring time is 5 min to 10 min.

5. The smelting and die-casting process of high-strength and toughness die-casting aluminum-silicon alloy according to claim 1, characterized in that: In S2-3, the purity of the pure Mg is ≥99.9%; the amount of the refining agent added is 0.9%-1.1% of the total mass of the melt in step S3.

6. The smelting and die-casting process of high-strength and toughness die-cast aluminum-silicon alloy according to claim 1, characterized in that: S3: The specific method of refining and purification is: adding a refining agent to the molten alloy melt, refining, standing, removing scum to obtain a purified melt.

7. The smelting and die-casting process of high-strength and toughness die-casting aluminum-silicon alloy according to claim 6, characterized in that: The refining agent is a three-in-one refining agent, and the amount of the refining agent added is 0.9%-1.1% of the mass of the smelted alloy melt; the number of refining times is ≥2 times.

8. The smelting and die-casting process of high-strength and toughness die-casting aluminum-silicon alloy according to claim 1, characterized in that: After S4 component testing and adjustment, it also includes transferring and keeping the purified melt warm.

9. The smelting and die-casting process of high-strength and toughness die-casting aluminum-silicon alloy according to claim 1, characterized in that: During S5 die-casting, the purified melt temperature is controlled at 690℃-700℃ for die-casting. The die-casting parameters are: mold temperature 180℃-250℃, low speed 0.20m / s-0.25m / s, high speed 2.7m / s-3.4m / s, high speed position 250mm-260mm, casting pressure 80MPa-90MPa, boost position 275mm-285mm, vacuum degree 40mbar-45mbar, and mold retention time 8s-12s.

10. A high-strength and toughness die-cast aluminum-silicon alloy, characterized in that: The alloy is prepared by the smelting and die-casting process of the high-strength and toughness die-casting aluminum-silicon alloy as described in any one of claims 1 to 9.

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