Fusion casting method of 4032 aluminum alloy

Abstract

The invention relates to the field of metal, in particular to a casting method of 4032 aluminum alloy. The casting method of the 4032 aluminum alloy provided by the invention comprises the following processes: burdening, pre-melting, overheating treatment, electromagnetic assistance, cooling treatment, stirring and refining, sampling, refining and standing, and casting. Through control of all the procedures, especially melt overheating treatment and low-frequency electromagnetic auxiliary stirring are utilized, original silicon phases and corresponding high-silicon-content cluster characteristics are eliminated, and gas protection is combined, so that homogeneous and pure melt is obtained; a cast ingot without a thick silicon phase is obtained by combining a rapid cooling method, regulating and controlling a melt to a lower temperature state and then through a post-adaptive casting process, the cast ingot is superior to a cast ingot microstructure of a conventional treatment method by adding a modificator, the problems of easy air suction, unstable silicon phase control, easy performance deterioration and the like caused by a conventional modification method are solved, and the method is pollution-free to the environment.

Description

Technical Field

[0001] The invention relates to the field of metals, and in particular to a melting and casting method of a 4032 aluminum alloy. Background Art

[0002] 4032 is a eutectic aluminum alloy, which is currently used to manufacture dynamic and static discs of new energy vehicles. Coarse silicon phase is easily formed in 4032 ingots, which has an adverse effect on the processing and service performance of subsequent products. At present, the silicon phase of 4032 aluminum alloy used in dynamic and static discs of new energy vehicles is no larger than 0.03mm, while the existing industry standard for 4032 ingots stipulates that the maximum size of its silicon phase shall not exceed 0.08mm, which can no longer meet the control requirements of silicon phase in existing application scenarios.

[0003] In order to solve the above problems, relevant studies have shown that the size of the silicon phase can be refined through processes such as modifier optimization, multi-pass deformation, and rapid solidification, but the effect is not ideal and the silicon phase cannot be effectively controlled below 0.3 mm. Moreover, the above methods cannot completely and stably control the silicon phase or cannot be applied in engineering. Therefore, it is urgent to develop a melting and casting method that can efficiently and stably control the silicon phase in an industrial manner. Summary of the invention

[0004] In view of this, the present invention provides a smelting and casting method of 4032 aluminum alloy. The method provided by the present invention can efficiently and stably control the silicon phase in the 4032 aluminum alloy in an industrial manner, and effectively solve the problem that the 4032 aluminum alloy is prone to form a coarse silicon phase.

[0005] The present invention provides a smelting and casting method of 4032 aluminum alloy, comprising the following steps: (A)Ingredients: The raw materials are batched according to the target alloy composition; Wherein, in terms of mass percentage, the composition of the target alloy is as follows: Si: 11%~13.5%; Ni: 0.5%~1.3%; Cu: 0.5%~1.3%; Mg: 0.8%~1.3%; The balance is Al and unavoidable impurities; The raw materials include: aluminum ingot, aluminum-silicon master alloy, aluminum-nickel master alloy, copper and magnesium; (B) Pre-melting: Put the aluminum-silicon master alloy and part of the aluminum ingot into a melting furnace and heat them for pre-melting; Among them, the said part of aluminum ingots accounts for 70% to 85% of the mass of all aluminum ingots; (C) Overheating and electromagnetic assistance: After the alloy in step (B) is melted, introduce protective gas into the smelting process until the protective gas volume reaches 8~10m 3 When the melt is heated to 850-950°C, electromagnetic stirring is turned on, and the mixture is kept warm and stirred for a certain period of time; (D) Cooling treatment: Put the remaining aluminum ingots, copper, magnesium and aluminum-nickel master alloy into the smelting furnace and control the temperature at 740~760℃; (E) Stirring and refining: Add refining agent to the smelting furnace for refining treatment, turn on electromagnetic stirring at the same time, and scrape off the surface slag after refining; (F) Refining and standing: The melt obtained in step (E) is transferred to a holding furnace, the temperature is controlled at 740-770°C, a refining agent is added to refine the melt, and electromagnetic stirring is turned on at the same time. After the refining is completed, the surface scum is scraped off and the melt is allowed to stand; (G) Casting: The melt obtained in step F) is cast to obtain a 4032 aluminum alloy ingot.

[0006] Preferably, in step (B), the pre-melting temperature is 740-760°C.

[0007] Preferably, in step (C), the electromagnetic frequency of the electromagnetic stirring is 5-20 Hz, and the time of the heat preservation stirring is 20-40 min.

[0008] Preferably, in step (C), the protective gas is nitrogen.

[0009] Preferably, in step (E), the electromagnetic frequency of the electromagnetic stirring is 0.7-4 Hz; and the refining time is 15-30 min.

[0010] Preferably, in step (E), the refining agent is MK4357B, and the amount used is 0.8-1.2 kg / t aluminum.

[0011] Preferably, in step (E), after the refining is completed and the surface scum is removed, the step further includes: sampling and analysis; The sampling and analysis includes: sampling in the melt, detecting the chemical composition of the alloy, if it meets the requirements, transferring to the next process, if it does not meet the requirements, diluting or supplementing.

[0012] Preferably, in step (F), the electromagnetic frequency of the electromagnetic stirring is 0.7-4 Hz; the refining time is 15-30 min; and the standing time is 20-50 min.

[0013] Preferably, in step (F), the refining agent is MK4357B, and the amount used is 0.8-1.2 kg / t aluminum.

[0014] Preferably, in step (G), the starting temperature of the casting is 730-760°C, the casting speed is 40-65 mm / min, and the water flow rate is 180-270 m / min. 3 / h.

[0015] Beneficial effects: In view of the problem that the silicon phase of the existing 4032 ingot does not meet the requirement of less than 0.03mm, the present invention provides a 4032 aluminum alloy melting and casting method, including the following process: batching - pre-melting - overheating treatment + electromagnetic assistance - cooling treatment - stirring and refining - sampling - refining and standing - casting. Through the control of the above processes, especially the use of melt overheating treatment + low-frequency electromagnetic assisted stirring, the original silicon phase and the corresponding high silicon content cluster characteristics are eliminated, and combined with gas protection, a homogeneous and pure melt is obtained; combined with a rapid cooling method, the melt is regulated to a lower temperature state, and then through a post-adaptive casting process, an ingot without coarse silicon phase is obtained, which is superior to the ingot microstructure of the conventional method of adding a modifier, and solves the problems of easy air inhalation, unstable silicon phase control, and easy performance deterioration caused by conventional modification methods, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0017] Figure 1 The microstructure diagram of the 4032 aluminum alloy ingot obtained in Example 1; Figure 2 The microstructure of the 4032 aluminum alloy ingot obtained in Comparative Example 1; Figure 3 This is the microstructure diagram of the 4032 aluminum alloy ingot obtained in Comparative Example 2. DETAILED DESCRIPTION

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0019] In this article, 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.

[0020] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0021] Herein, when it comes to numerical ranges, unless otherwise specified, the numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every 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.

[0022] 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, 850~950℃ means that the units of the left endpoint "850" and the right endpoint "950" are both ℃.

[0023] The present invention provides a smelting and casting method of 4032 aluminum alloy, comprising the following steps: (A)Ingredients: The raw materials are batched according to the target alloy composition; Wherein, in terms of mass percentage, the composition of the target alloy is as follows: Si: 11%~13.5%; Ni: 0.5%~1.3%; Cu: 0.5%~1.3%; Mg: 0.8%~1.3%; The balance is Al and unavoidable impurities; The raw materials include: aluminum ingot, aluminum-silicon master alloy, aluminum-nickel master alloy, copper and magnesium; (B) Pre-melting: Put the aluminum silicon middle and part of the aluminum ingot into the melting furnace and heat and pre-melt; Among them, the said part of aluminum ingots accounts for 70% to 85% of the mass of all aluminum ingots; (C) Overheating and electromagnetic assistance: After the alloy in step (B) is melted, introduce protective gas into the melting furnace until the protective gas volume reaches 8~10m 3 When the melt is heated to 850-950°C, electromagnetic stirring is turned on, and the mixture is kept warm and stirred for a certain period of time; (D) Cooling treatment: Put the remaining aluminum ingots, copper, magnesium and aluminum-nickel master alloy into the smelting furnace and control the temperature at 740~760℃; (E) Stirring and refining: Add refining agent to the smelting furnace for refining treatment, turn on electromagnetic stirring at the same time, and scrape off the surface slag after refining; (F) Refining and standing: The melt obtained in step (E) is transferred to a holding furnace, the temperature is controlled at 740-770°C, a refining agent is added to refine the melt, and electromagnetic stirring is turned on at the same time. After the refining is completed, the surface scum is scraped off and the melt is allowed to stand; (G) Casting: The melt obtained in step (F) is cast to obtain a 4032 aluminum alloy ingot.

[0024] In step (A), The Si (silicon) content may specifically be 11.0%, 11.1%, 11.2%, 11.3%, 11.4%, 11.5%, 11.6%, 11.7%, 11.8%, 11.9%, 12.0%, 12.1%, 12.2%, 12.3%, 12.4%, 12.5%, 12.6%, 12.7%, 12.8%, 12.9%, 13.0%, 13.1%, 13.2%, 13.3%, 13.4%, and 13.5%.

[0025] The Ni (nickel) content may specifically be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, or 1.3%.

[0026] The Cu (copper) content may specifically be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, or 1.3%.

[0027] The content of Mg (magnesium) may specifically be 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, or 1.3%.

[0028] The balance is Al and inevitable impurities.

[0029] In some embodiments of the present invention, the alloy composition is as follows: Si 11.8%, Ni 0.8%, Cu 0.9%, Mg 1.1%, and the balance is Al and inevitable impurities.

[0030] In the present invention, the raw materials used include: aluminum ingot, aluminum silicon master alloy, aluminum nickel master alloy, copper and magnesium. The present invention has no special restrictions on the method of mixing ingredients, and it can be carried out according to conventional means in the art, such as calculating the proportion of each raw material according to the target composition, and weighing the corresponding amount of raw materials for use.

[0031] In the present invention, the aluminum ingot is added in two times, a portion is added first in step (B), and the remaining portion is added in a subsequent step. In the present invention, the portion of the aluminum ingot in step B) accounts for 70% to 85% of the mass of the entire aluminum ingot, specifically 70%, 75%, 80%, and 85%.

[0032] In the present invention, the pre-melting temperature is preferably 740-760°C, specifically 740°C, 745°C, 750°C, 755°C, or 760°C.

[0033] In the present invention, after the alloy in step (B) is melted, a protective gas is introduced into the smelting furnace. The type of the protective gas is not particularly limited, and it can be a conventional protective gas in the art, such as nitrogen, argon, etc. The protective gas is introduced until the protective gas volume reaches 8-10m 3 , specifically 8m 3 、9m 3 、10m 3 . When the amount of protective gas reaches the above target, the melt is heated to 850~950℃, specifically 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃, 940℃, 950℃. After the melt reaches the above temperature, start insulation and start electromagnetic stirring at the same time, and keep warm and stir for a certain time. In the present invention, the electromagnetic frequency of the electromagnetic stirring is preferably 5~20Hz, specifically 5Hz, 10Hz, 15Hz, 20Hz. The insulation time and stirring time are the same, and the insulation and stirring time is preferably 20~40min, specifically 20min, 25min, 30min, 35min, 40min.

[0034] In the present invention, after step (C) is completed, the cold material (i.e., the remaining aluminum ingot, pure copper, pure magnesium and aluminum-nickel master alloy) is put into the smelting furnace, and the cold material melts and takes away the heat to achieve cooling. The present invention controls the temperature at 740-760°C, specifically 740°C, 745°C, 750°C, 755°C, 760°C.

[0035] After the temperature in step (D) is lowered to the target temperature, a refining agent is added to the smelting furnace for refining treatment. In the present invention, the refining agent is preferably MK4357B. The amount of the refining agent is preferably 0.8-1.2 kg / t aluminum, specifically 0.8 kg / t aluminum, 0.9 kg / t aluminum, 1.0 kg / t aluminum, 1.1 kg / t aluminum, 1.2 kg / t aluminum.

[0036] Electromagnetic stirring is turned on while adding the refining agent for refining, that is, electromagnetic stirring is accompanied during the refining process. The electromagnetic frequency of the electromagnetic stirring is preferably 0.7-4 Hz, specifically 0.7 Hz, 1.0 Hz, 1.2 Hz, 1.5 Hz, 2.0 Hz, 2.5 Hz, 3.0 Hz, 3.5 Hz, 4.0 Hz. The refining time is preferably 15-30 min, specifically 15 min, 20 min, 25 min, 30 min. After refining, remove the surface scum.

[0037] In the present invention, after step (E) is completed, sampling and analysis are preferably performed. Specifically, sampling is performed in the melt to detect the chemical composition of the alloy. If the requirements are met, the next process is performed. If the requirements are not met, dilution or supplementation is performed.

[0038] In the present invention, after step (E) is completed, the obtained melt is transferred to a holding furnace and the temperature is controlled to be 740-770°C, specifically 740°C, 745°C, 750°C, 755°C, 760°C, 765°C, or 770°C.

[0039] In the present invention, the refining agent is added under the above temperature for refining. The refining agent is preferably MK4357B. The amount of the refining agent is preferably 0.8-1.2 kg / t aluminum, specifically 0.8 kg / t aluminum, 0.9 kg / t aluminum, 1.0 kg / t aluminum, 1.1 kg / t aluminum, 1.2 kg / t aluminum.

[0040] In the present invention, electromagnetic stirring is turned on while adding a refining agent for refining, that is, electromagnetic stirring is accompanied during the refining process. The electromagnetic frequency of the electromagnetic stirring is preferably 0.7~4Hz, specifically 0.7Hz, 1.0Hz, 1.2Hz, 1.5Hz, 2.0Hz, 2.5Hz, 3.0Hz, 3.5Hz, 4.0Hz. The refining time is preferably 15~30min, specifically 15min, 20min, 25min, 30min. After refining, remove the surface scum and let it stand. The standing time is preferably 20~50min, specifically 20min, 25min, 30min, 35min, 40min, 45min, 50min.

[0041] In the present invention, the starting temperature of the casting is preferably 730-760°C, specifically 730°C, 735°C, 740°C, 745°C, 750°C, 755°C, 760°C. The casting speed is preferably 40-65 mm / min, specifically 40 mm / min, 45 mm / min, 50 mm / min, 55 mm / min, 60 mm / min, 65 mm / min. The water flow rate of the casting is preferably 180-270 m 3 / h, specifically 180m 3 / h、190m 3 / h、200m 3 / h、210m 3 / h、220m 3 / h、230m 3 / h、240m 3 / h、250m 3 / h、260m 3 / h、270m 3 / h. After casting, a 4032 aluminum alloy ingot is obtained.

[0042] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0043] Example 1 (A)Ingredients: The target alloy composition is: Si 11.8%, Ni 0.8%, Cu 0.9%, Mg 1.1%, and the balance is Al and inevitable impurities. According to the above target alloy composition, pure aluminum ingot, aluminum-silicon master alloy, aluminum-nickel master alloy, pure metal copper and pure metal magnesium are weighed.

[0044] (B) Pre-melting: The aluminum-silicon master alloy and 80% pure aluminum ingot are placed in a melting furnace and heated to 740°C for pre-melting.

[0045] (C) Overheating and electromagnetic assistance: After the alloy in step (B) is melted, nitrogen protection is introduced into the melting furnace until the nitrogen gas volume reaches 9m 3 The melt was heated to 880°C, and after reaching this temperature, insulation was started while electromagnetic stirring was turned on, the electromagnetic frequency was set to 10 Hz, and insulation and stirring were performed for 30 minutes.

[0046] (D) Cooling treatment: Put the remaining 20% ​​pure aluminum ingot into the furnace, and then put pure copper, pure magnesium, and aluminum-nickel intermediate alloy into the furnace, and control the temperature at 755℃.

[0047] (E) Stirring and refining: Refining agent MK4357B (dosage: 0.8kg / t aluminum) was added to the smelting furnace for refining treatment. At the same time, electromagnetic stirring was turned on and the electromagnetic frequency was set to 1.2HZ. The stirring and refining were performed for 25 minutes. After the refining was completed, the surface slag was scraped off.

[0048] Take samples from the melt and test the chemical composition of the alloy. If it meets the requirements, it will be transferred to the next process. If it does not meet the requirements, it will be diluted or supplemented.

[0049] (F) Refining and standing: The melt obtained in step (E) was transferred to a holding furnace, the temperature was controlled at 755°C, and refining agent MK4357B (dosage: 0.8 kg / t aluminum) was added to refine the melt. At the same time, electromagnetic stirring was turned on, and the electromagnetic frequency was set to 1.2 Hz. The stirring and refining were performed for 20 minutes. After the refining was completed, the surface scum was scraped off and the melt was allowed to stand for 40 minutes.

[0050] (G) Casting: The melt obtained in step (F) was cast, the starting temperature was controlled at 745°C, the casting speed was 50 mm / min, and the water flow rate was 210 m 3 / h, the casting is completed and a 4032 aluminum alloy ingot is obtained.

[0051] Example 2 (A)Ingredients: The target alloy composition is: Si 11.8%, Ni 0.8%, Cu 0.9%, Mg 1.1%, and the balance is Al and inevitable impurities. According to the above target alloy composition, pure aluminum ingot, aluminum-silicon master alloy, aluminum-nickel master alloy, pure metal copper and pure metal magnesium are weighed.

[0052] (B) Pre-melting: The aluminum-silicon master alloy and 75% pure aluminum ingot are placed in a melting furnace and heated to 760°C for pre-melting.

[0053] (C) Overheating and electromagnetic assistance: After the alloy in step (B) is melted, nitrogen protection is introduced into the melting furnace until the nitrogen gas volume reaches 9m 3 The melt was heated to 920°C, and after reaching this temperature, insulation was started while electromagnetic stirring was turned on, the electromagnetic frequency was set to 15 Hz, and insulation and stirring were performed for 30 minutes.

[0054] (D) Cooling treatment: Put the remaining 25% pure aluminum ingot into the furnace, and then put pure copper, pure magnesium, and aluminum-nickel intermediate alloy into the furnace, and control the temperature at 755℃.

[0055] (E) Stirring and refining: Refining agent MK4357B (dosage: 1.2kg / t aluminum) was added to the smelting furnace for refining. At the same time, electromagnetic stirring was turned on and the electromagnetic frequency was set to 1.2HZ. The stirring and refining were performed for 25 minutes. After the refining was completed, the slag on the surface was scraped off.

[0056] Take samples from the melt and test the chemical composition of the alloy. If it meets the requirements, it will be transferred to the next process. If it does not meet the requirements, it will be diluted or supplemented.

[0057] (F) Refining and standing: The melt obtained in step (E) was transferred to a holding furnace, the temperature was controlled at 750°C, and refining agent MK4357B (dosage: 1.2 kg / t aluminum) was added to refine the melt. At the same time, electromagnetic stirring was turned on, and the electromagnetic frequency was set to 1.2 Hz. The stirring and refining were performed for 25 minutes. After the refining was completed, the surface scum was scraped off and the melt was allowed to stand for 30 minutes.

[0058] (G) Casting: The melt obtained in step (F) was cast, the starting temperature was controlled at 740°C, the casting speed was 45 mm / min, and the water flow rate was 190 m 3 / h, the casting is completed and a 4032 aluminum alloy ingot is obtained.

[0059] Comparative Example 1 (1) Ingredients: The target alloy composition is: Si 11.8%, Ni 0.8%, Cu 0.9%, Mg 1.1%, and the balance is Al and inevitable impurities. According to the above target alloy composition, pure aluminum ingot, aluminum-silicon master alloy, aluminum-nickel master alloy, pure metal copper and pure metal magnesium are weighed.

[0060] (2) Pure aluminum ingots, pure copper, pure magnesium, aluminum-silicon master alloy, and aluminum-nickel master alloy are placed in a melting furnace and heated to 740°C for pre-melting.

[0061] (3) After the alloy in step (2) is melted, the temperature is controlled at 755°C, and refining agent MK4357B (dosage is 0.8 kg / t aluminum) is added for refining. At the same time, electromagnetic stirring is turned on, and the electromagnetic frequency is set to 1.2 Hz. Stir and refine for 25 minutes. After refining, the surface scum is scraped off.

[0062] Take samples from the melt and test the chemical composition of the alloy. If it meets the requirements, it will be transferred to the next process. If it does not meet the requirements, it will be diluted or supplemented.

[0063] (4) The melt obtained in step (3) is transferred to a holding furnace, the temperature of which is controlled at 755°C, and aluminum-strontium alloy is added for modification, and the strontium content is controlled at 0.03%. Then, a refining agent MK4357B (the dosage is 0.8 kg / t aluminum) is added to refine the melt, and electromagnetic stirring is turned on at the same time, and the electromagnetic frequency is set to 1.2 Hz. The stirring and refining are carried out for 20 minutes. After the refining is completed, the surface scum is scraped off and the melt is allowed to stand for 40 minutes.

[0064] (5) Casting: The melt obtained in step (4) is cast, the starting temperature is controlled at 745°C, the casting speed is 50 mm / min, and the water flow rate is 210 m 3 / h, the casting is completed and a 4032 aluminum alloy ingot is obtained.

[0065] Comparative Example 2 (A)Ingredients: The target alloy composition is: Si 11.8%, Ni 0.8%, Cu 0.9%, Mg 1.1%, and the balance is Al and inevitable impurities. According to the above target alloy composition, pure aluminum ingot, aluminum-silicon master alloy, aluminum-nickel master alloy, pure metal copper and pure metal magnesium are weighed.

[0066] (B) Pre-melting: The aluminum-silicon master alloy and 80% pure aluminum ingot are placed in a melting furnace and heated to 740°C for pre-melting.

[0067] (C) Overheating treatment: After the alloy in step (B) is melted, nitrogen protection is introduced into the melting furnace until the nitrogen gas volume reaches 9m 3 The melt was heated to 880°C and kept warm for 30 min.

[0068] (D) Cooling treatment: Put the remaining 20% ​​pure aluminum ingot into the furnace, and then put pure copper, pure magnesium, and aluminum-nickel intermediate alloy into the furnace, and control the temperature at 755℃.

[0069] (E) Stirring and refining: Refining agent MK4357B (dosage: 0.8kg / t aluminum) was added to the smelting furnace for refining treatment. At the same time, electromagnetic stirring was turned on and the electromagnetic frequency was set to 1.2HZ. The stirring and refining were performed for 25 minutes. After the refining was completed, the surface slag was scraped off.

[0070] Take samples from the melt and test the chemical composition of the alloy. If it meets the requirements, it will be transferred to the next process. If it does not meet the requirements, it will be diluted or supplemented.

[0071] (F) Refining and standing: The melt obtained in step (E) was transferred to a holding furnace, the temperature was controlled at 755°C, and refining agent MK4357B (dosage: 0.8 kg / t aluminum) was added to refine the melt. At the same time, electromagnetic stirring was turned on, and the electromagnetic frequency was set to 1.2 Hz. The stirring and refining were performed for 20 minutes. After the refining was completed, the surface scum was scraped off and the melt was allowed to stand for 40 minutes.

[0072] (G) Casting: The melt obtained in step (F) was cast, the starting temperature was controlled at 745°C, the casting speed was 50 mm / min, and the water flow rate was 210 m 3 / h, the casting is completed and a 4032 aluminum alloy ingot is obtained.

[0073] The microstructures of the alloys obtained in Example 1, Comparative Example 1 and Comparative Example 2 are as follows: Figure 1-3 As shown, among which, Figure 1 It can be seen that the silicon phase of the 4032 aluminum alloy ingot prepared by the method of the present invention can be controlled below 0.03 mm; Figure 2-3 It can be seen that the 4032 aluminum alloy ingots obtained by the conventional method of Comparative Example 1 and the method of Comparative Example 2 without adding medium and low frequency electromagnetic assisted stirring in the melt superheating treatment both have silicon phases greater than 0.03 mm. The 4032 aluminum alloy melting and casting method provided by the present invention utilizes melt superheating treatment + low frequency electromagnetic assisted stirring to eliminate the original silicon phase and the corresponding high silicon content cluster characteristics, and combines gas protection to obtain a homogeneous and pure melt; combined with a rapid cooling method, the melt is regulated to a lower temperature state, and then a post-adapted casting process is used to obtain an ingot without a coarse silicon phase.

[0074] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for melting and casting 4032 aluminum alloy, characterized in that: The following steps are involved: (A)Ingredients: The raw materials are batched according to the target alloy composition; Wherein, in terms of mass percentage, the composition of the target alloy is as follows: Si: 11%~13.5%; Ni: 0.5%~1.3%; Cu: 0.5%~1.3%; Mg: 0.8%~1.3%; The balance is Al and unavoidable impurities; The raw materials include: aluminum ingot, aluminum-silicon master alloy, aluminum-nickel master alloy, copper and magnesium; (B) Pre-melting: Put the aluminum-silicon master alloy and part of the aluminum ingot into a melting furnace and heat them for pre-melting; Among them, the said part of aluminum ingots accounts for 70% to 85% of the mass of all aluminum ingots; (C) Overheating and electromagnetic assistance: After the alloy in step (B) is melted, introduce protective gas into the smelting process until the protective gas volume reaches 8-10m 3 When the melt is heated to 850-950°C, electromagnetic stirring is turned on, and the mixture is kept warm and stirred for a certain period of time; (D) Cooling treatment: Put the remaining aluminum ingots, copper, magnesium and aluminum-nickel master alloy into the smelting furnace and control the temperature at 740~760℃; (E) Stirring and refining: Add refining agent to the smelting furnace for refining treatment, turn on electromagnetic stirring at the same time, and scrape off the surface slag after refining; (F) Refining and standing: The melt obtained in step (E) is transferred to a holding furnace, the temperature is controlled at 740-770°C, a refining agent is added to refine the melt, and electromagnetic stirring is turned on at the same time. After the refining is completed, the surface scum is scraped off and the melt is allowed to stand; (G) Casting: The melt obtained in step (F) is cast to obtain a 4032 aluminum alloy ingot.

2. The melting and casting method according to claim 1, characterized in that: In step (B), the heating pre-melting temperature is 740-760°C.

3. The melting and casting method according to claim 1, characterized in that: In step (C), the electromagnetic frequency of the electromagnetic stirring is 5-20 Hz, and the time of the heat preservation stirring is 20-40 min.

4. The melting and casting method according to claim 1, characterized in that: In step (C), the protective gas is nitrogen.

5. The melting and casting method according to claim 1, characterized in that: In step (E), the electromagnetic frequency of the electromagnetic stirring is 0.7-4 Hz; and the refining time is 15-30 min.

6. The melting and casting method according to claim 1, characterized in that: In step (E), the refining agent is MK4357B, and the amount used is 0.8-1.2 kg / t aluminum.

7. The melting and casting method according to claim 1, characterized in that: In step (E), after the refining is completed and the surface scum is removed, the process further comprises: sampling and analysis; The sampling and analysis includes: sampling in the melt, detecting the chemical composition of the alloy, if it meets the requirements, transferring to the next process, if it does not meet the requirements, diluting or supplementing.

8. The melting and casting method according to claim 1, characterized in that: In step (F), the electromagnetic frequency of the electromagnetic stirring is 0.7-4 Hz; the refining time is 15-30 min; and the standing time is 20-50 min.

9. The melting and casting method according to claim 1, characterized in that: In step (F), the refining agent is MK4357B, and the amount used is 0.8-1.2 kg / t aluminum.

10. The melting and casting method according to claim 1, characterized in that: In step (G), the starting temperature of the casting is 730-760°C, the casting speed is 40-65 mm / min, and the water flow rate is 180-270 m / min. 3 / h.

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