Preparation method and application of low-melting-point high-cleanliness AlFe10 intermediate alloy

Abstract

The invention discloses a preparation method of a low-melting-point high-cleanliness AlFe10 intermediate alloy. The low-melting-point high-cleanliness AlFe10 intermediate alloy comprises the following components: 9-11% of Fe, 0.03-0.40% of Mn, less than or equal to 0.02% of Pb, less than or equal to 0.02% of Sn, less than or equal to 0.04% of Zn, less than or equal to 0.10% of C, less than or equal to 0.04% of single impurities, less than or equal to 0.15% of total impurities and the balance of Al. The preparation method of the intermediate alloy comprises the following steps: 1) melting aluminum; (2) the temperature is increased to 900-1000 DEG C, pure iron is slowly added, and a graphite rod is used for blowing argon and stirring while the pure iron is added; (3) after the pure iron is completely melted, the temperature is increased to 950-1050 DEG C, the argon pressure is adjusted to 0.01-0.03 MPa, a ventilated graphite rod is immersed into the molten aluminum for argon refining, and the refining time is 10-20 minutes; 4, after refining is finished, the graphite rod is taken out, an argon valve is closed, standing is conducted for 2-5 minutes, slagging-off, pouring and cooling are conducted, operation is easy, the obtained intermediate alloy is uniform, fine, free of burning loss and low in melting point, the preparation temperature of adding iron into the aluminum alloy is remarkably reduced, operation is simplified, the conversion rate of iron is increased, and the product quality of the obtained alloy is improved.

Description

Technical Field

[0001] This invention relates to a method for preparing a low-melting-point, high-purity AlFe10 master alloy and its application, belonging to the field of AlFe10 master alloy preparation technology. Background Technology

[0002] Aluminum alloys are widely used in various industrial fields such as construction, automobiles, and electronics due to their advantages such as low density, high specific strength, and good processability. During the production of aluminum alloys, iron is a common alloying or impurity element, and its content has a decisive influence on the properties of aluminum alloys.

[0003] Due to the significant difference in melting points between aluminum and iron, iron is difficult to dissolve uniformly in molten aluminum during conventional smelting processes, which easily leads to local segregation. This results in large fluctuations in iron content in different parts of the ingot, as well as high operating temperatures, severe burn-off, poor uniformity, and low conversion rates.

[0004] This invention provides a method for preparing a low-melting-point, high-purity AlFe10 master alloy and its application. The preparation method is simple, the resulting master alloy has a low melting point, significantly reduces the preparation temperature for adding iron, simplifies the operation, improves the iron conversion rate, and enhances the product quality of the resulting alloy. Summary of the Invention

[0005] This invention provides a method for preparing a low-melting-point, high-purity AlFe10 master alloy and its application, which solves the technical problems of high temperature, severe burn-off, and poor uniformity when iron is added.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a low-melting-point, high-purity AlFe10 master alloy, wherein the composition of the low-melting-point, high-purity AlFe master alloy is: Fe: 9~11%, Mn: 0.03~0.40%, Pb≤0.02%, Sn≤0.02%, Zn≤0.04%, C≤0.10%, single impurity ≤0.04%, total impurities ≤0.15%, Al: balance; all percentages are by mass.

[0008] The preparation method of low-melting-point, high-purity AlFe master alloy includes the following steps:

[0009] 1) Put aluminum ingots into an intermediate frequency furnace and melt them completely at a temperature of 750-850℃, or transfer molten aluminum at a temperature of 750-850℃;

[0010] 2) After the aluminum ingots have completely melted, heat the temperature to 900-1000℃ and slowly add the weighed pure iron. While adding the pure iron, use a graphite rod to blow argon gas and stir to prevent the unalloyed iron from sinking to the bottom of the crucible and accelerating the "melting and erosion".

[0011] 3) After the pure iron is completely melted, heat it to 950-1050℃, adjust the argon pressure to 0.01-0.03MPa, immerse the vented graphite rod in the aluminum liquid for argon refining. When degassing, pay attention to liquid splashing and do not blow air at a fixed point. The refining time is 10-20 minutes.

[0012] 4) After refining, remove the graphite rod, close the argon valve, let it stand for 2-5 minutes, remove the slag, pour and cool.

[0013] After casting, packaging and other operations are carried out.

[0014] The above method involves low temperature, simple operation, and easy control.

[0015] Unless otherwise specified, all percentages in this application are percentages by mass.

[0016] To further improve the uniformity of the obtained low-melting-point, high-purity AlFe10 master alloy, the pure iron is added for 20-60 minutes in step 2) above.

[0017] To further improve product quality, in step 2) above, the argon flow rate is 1.2-1.4 m³ / h. In step 3) above, during the refining process, the argon flow rate is 1.2-1.4 m³ / h.

[0018] In step 4) above, during casting, the temperature of the alloy liquid is 950-1050℃, and the mold temperature is 100-250℃. In step 4) above, during cooling, cooling water at a temperature of 20-40℃ is used to cool the mold.

[0019] The AlFe master alloy obtained by the above method has fine crystals, high internal purity, no burn-off, high yield, and low melting point. It also significantly improves the yield during use and reduces the addition temperature.

[0020] In step 2) above, the mass ratio of molten aluminum to pure iron is 1000:103.

[0021] The low-melting-point, high-purity AlFe10 master alloy obtained above is used as an additive in aluminum alloys.

[0022] As one preferred implementation, the raw materials used in the aluminum alloy include: pure aluminum ingots, high-iron aluminum ingots and low-melting-point, high-purity AlFe10 master alloy, with a mass ratio of pure aluminum ingots, high-iron aluminum ingots and low-melting-point, high-purity AlFe10 master alloy of 32:2:0.83; the iron content in the high-iron aluminum ingots is 0.50%.

[0023] The above-mentioned aluminum alloy is prepared using a one-step feeding method, which includes the following steps:

[0024] 1) Melt all the pure aluminum ingots, high-iron aluminum ingots, and low-melting-point, high-purity AlFe10 master alloy at a temperature of 700~720℃ and stir well;

[0025] 2) Add light calcium carbonate and crush. After crushing, keep warm at 700~720℃ and stir for 10~15 minutes.

[0026] 3) Heat to 740~760℃ and transfer to a refining furnace for refining in three stages: First refining: purge with argon gas, turn on the graphite rotor to stir, add refining agent, refine for 15~20 minutes, and remove slag; Second refining: purge with argon gas, stir with the graphite rotor, add refining agent, refine for 5~10 minutes, and remove slag; Third refining: purge with argon gas, stir with the graphite rotor, refine for 15~20 minutes, remove slag, and cast.

[0027] To further improve the uniformity of the alloy, in step 3), the refining agent is a mixture of a eutectic salt and a regulator with a mass ratio of (98~99):(2~1); the eutectic salt is a KCl-NaCl eutectic salt, wherein the mass ratio of KCl to NaCl is 6:4; the regulator is a mixture of CeCl3·7H2O and LaCl3·7H2O with a mass ratio of 1:1.

[0028] In step 3) above, the argon pressure is maintained at 0.1~0.3MPa during the three refining processes; the graphite rotor speed is 300~350R / min.

[0029] Any techniques not mentioned in this invention are based on existing technologies.

[0030] The present invention provides a method for preparing a low-melting-point, high-purity AlFe10 master alloy. The method is simple to operate and produces a uniform, fine AlFe10 master alloy with no burn-off and a low melting point. It significantly reduces the preparation temperature of aluminum alloy with added iron, simplifies the operation, improves the iron conversion rate, and enhances the product quality of the resulting alloy. Attached Figure Description

[0031] Figure 1 This is a photograph of the low-melting-point, high-purity AlFe master alloy obtained in Example 1 of the present invention.

[0032] Figure 2 The image shows the fracture surface of the low-melting-point, high-purity AlFe master alloy obtained in Example 1 of this invention.

[0033] Figure 3 A photograph of the AlFe10 master alloy obtained in Comparative Example 2;

[0034] Figure 4 The fracture surface photograph of the AlFe10 master alloy obtained in Comparative Example 2 is shown. Detailed Implementation

[0035] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0036] Example 1

[0037] Preparation of low-melting-point, high-purity AlFe10 master alloy:

[0038] Materials: 1000 kg of aluminum ingots (Al content ≥ 99.7%, iron content: 0.12%); 103 kg of pure iron (Fe content ≥ 99.5%, iron cylinders with a diameter of 20 mm, cut into 2 cm long granules after pre-shearing).

[0039] The preparation method of low-melting-point, high-purity AlFe master alloy includes the following steps:

[0040] 1) The aluminum ingots are placed into an intermediate frequency furnace and melted completely at a temperature of 760℃;

[0041] 2) After the aluminum ingots have completely melted, heat the temperature to 920℃ and slowly add the weighed pure iron (addition time is 30min). While adding the pure iron, blow argon gas (1.3m³ / h) with a graphite rod and stir (300R / min) to prevent the unalloyed iron from sinking to the bottom of the crucible and accelerating the "melting".

[0042] 3) After the pure iron is completely melted, heat it to 960℃, adjust the argon pressure to 0.02MPa, immerse the vented graphite rod in the aluminum liquid for argon (1.3m³ / h) refining. When degassing, pay attention to liquid splashing and do not blow air at a fixed point. The refining time is 15 minutes.

[0043] 4) After refining, remove the graphite rod, close the argon valve, let it stand for 5 minutes, remove the slag, and pour (alloy liquid temperature 960℃, mold temperature 200℃), then cool (using cooling water at 20-25℃ to cool the mold) to obtain a low-melting-point, high-purity AlFe10 master alloy with a melting point of 680℃. Figure 1-2 As shown, the alloy surface and interior exhibit fine crystallization with no burn-off or oxides.

[0044] The composition of the low-melting-point, high-purity AlFe10 master alloy was determined by spectrometer, and the results are shown in the table below.

[0045] Example 2:

[0046] The 35-ton furnace was charged with the following materials: 32 tons of pure aluminum ingots (aluminum content ≥99.7%, iron content: 0.12%) + 2 tons of high-speed iron aluminum ingots (aluminum content ≈99.5%, iron content: 0.50%) + 0.83 tons of AlFe10 master alloy (prepared according to Example 1).

[0047] Aluminum-iron alloys were prepared using a one-step feeding method.

[0048] 1) Melt all the pure aluminum ingots, high-iron aluminum ingots, and low-melting-point, high-purity AlFe10 master alloy at 700℃ and stir well;

[0049] 2) Add 32kg of light calcium carbonate and crush it. After crushing, keep it at 700℃ and stir (300R / min) for 15min.

[0050] 3) Heat to 750℃ and transfer to a refining furnace for refining in three stages: First refining: purge with argon gas (0.3MPa), start the graphite rotor stirring (300R / min), and add 32kg of refining agent (a mixture of eutectic salt and regulator with a mass ratio of 98:2; the eutectic salt is a KCl-NaCl eutectic salt, where the mass ratio of KCl to NaCl is 6:4; the regulator is a mixture of CeCl3·7H2O and LaCl3·7H2O with a mass ratio of 1:1), refine for 15min, and skim off the slag; Second refining: purge with argon gas (0.3MPa), start the graphite rotor stirring (300R / min), and... Add 32 kg of refining agent (a mixture of eutectic salt and regulator with a mass ratio of 98:2; the eutectic salt is KCl-NaCl eutectic salt, wherein the mass ratio of KCl to NaCl is 6:4; the regulator is a mixture of CeCl3·7H2O and LaCl3·7H2O with a mass ratio of 1:1), refine for 5 min, and remove slag; third refining: pass argon gas (0.3 MPa), stir with a graphite rotor (300 R / min), refine for 15 min, remove slag, and cast (the alloy liquid temperature is 750℃, the mold temperature is 150℃, and the mold is cooled with cooling water at a temperature of 20-25℃) to obtain an aluminum-iron alloy.

[0051] Test points were taken at three cross-sections (top, middle, and bottom) of the aluminum-iron alloy, with nine test points at each cross-section: one point at the center, four points at the inner ring, and four points at the outer ring, totaling 27 points. The iron content was determined using a spectrometer. The average iron content was 0.382%, with a yield of 99.5%; the relative standard deviation (RSD) was 0.11%.

[0052] Comparative Example 1

[0053] The difference from Example 2 is that the AlFe10 master alloy in Example 2 was replaced with 0.085 tons of pure iron and 0.745 tons of pure aluminum, while the rest remained the same as in Example 2. The iron could not be melted.

[0054] Comparative Example 2

[0055] The difference from Example 2 is that pure iron was replaced with Q195 carbon steel in the preparation of the AlFe10 master alloy. All other aspects are the same as in Example 2. Figure 3-4It can be seen that the AlFe10 master alloy obtained in this example has coarse grains on the surface and inside, and obvious burn-off problems. The iron yield is 93.2%, and the RSD is 8.6%.

[0056] Comparative Example 3

[0057] The difference from Example 2 is that in preparing the AlFe10 master alloy, the refining agent in step 3) was replaced with a KCl-NaCl eutectic salt. All other steps were the same as in Example 2. The RSD was 2.0%.

[0058] Comparative Example 4

[0059] The difference from Example 2 is that in preparing the AlFe10 master alloy, the refining agent in step 3) was replaced with a regulator. All other steps were the same as in Example 2. The RSD was 1.9%.

Claims

1. A method for preparing a low-melting-point, high-purity AlFe10 master alloy, characterized in that: The composition of the low-melting-point, high-purity AlFe master alloy is as follows: Fe: 9~11%, Mn: 0.03~0.40%, Pb≤0.02%, Sn≤0.02%, Zn≤0.04%, C≤0.10%, single impurity ≤0.04%, total impurities ≤0.15%, Al: balance; all percentages are by mass. The preparation method of low-melting-point, high-purity AlFe master alloy includes the following steps: 1) Put aluminum ingots into an intermediate frequency furnace and melt them completely at a temperature of 750-850℃, or transfer molten aluminum at a temperature of 750-850℃; 2) After the aluminum ingots have completely melted, heat the temperature to 900-1000℃, slowly add the weighed pure iron, and stir with argon gas using a graphite rod while adding the pure iron. 3) After the pure iron is completely melted, heat it to 950-1050℃, adjust the argon pressure to 0.01-0.03MPa, and immerse the ventilated graphite rod in the aluminum liquid for argon refining. The refining time is 10-20 minutes. 4) After refining, remove the graphite rod, close the argon valve, let it stand for 2-5 minutes, remove the slag, pour and cool.

2. The method for preparing the low-melting-point, high-purity AlFe10 master alloy according to claim 1, characterized in that: In step 2), the pure iron is added over a period of 20-60 minutes.

3. The method for preparing the low-melting-point, high-purity AlFe10 master alloy according to claim 1 or 2, characterized in that: In step 2), the argon flow rate is 1.2-1.4 m³ / h.

4. The method for preparing the low-melting-point, high-purity AlFe10 master alloy according to claim 1 or 2, characterized in that: In step 3), during the refining process, the argon flow rate is 1.2-1.4 m³ / h.

5. The method for preparing the low-melting-point, high-purity AlFe10 master alloy according to claim 1 or 2, characterized in that: In step 2), the mass ratio of molten aluminum to pure iron is 1000:

103.

6. The use of an intermediate alloy prepared by the method for preparing a low-melting-point, high-purity AlFe10 intermediate alloy according to any one of claims 1-5, characterized in that: Used for adding to aluminum alloy components.

7. The use according to claim 6, characterized in that: The raw materials used in the aluminum alloy include: pure aluminum ingots, high-iron aluminum ingots and low-melting-point, high-purity AlFe10 master alloy. The mass ratio of pure aluminum ingots, high-iron aluminum ingots and low-melting-point, high-purity AlFe10 master alloy is 32:2:0.83; the iron content in the high-iron aluminum ingots is 0.50%.

8. The use according to claim 7, characterized in that: Aluminum alloys are prepared using a one-step feeding method, which includes the following steps: 1) Melt all the pure aluminum ingots, high-iron aluminum ingots, and low-melting-point, high-purity AlFe10 master alloy at a temperature of 700~720℃ and stir well; 2) Add light calcium carbonate and crush. After crushing, keep warm at 700~720℃ and stir for 10~15 minutes. 3) Heat to 740~760℃ and transfer to a refining furnace for refining in three stages: First refining: purge with argon gas, turn on the graphite rotor to stir, add refining agent, refine for 15~20 minutes, and remove slag; Second refining: purge with argon gas, stir with the graphite rotor, add refining agent, refine for 5~10 minutes, and remove slag; Third refining: purge with argon gas, stir with the graphite rotor, refine for 15~20 minutes, remove slag, cast, and cool.

9. The use according to claim 8, characterized in that: In step 3), the refining agent is a mixture of a eutectic salt and a regulator in a mass ratio of (98~99):(2~1); the eutectic salt is a KCl-NaCl eutectic salt, wherein the mass ratio of KCl to NaCl is 6:4; the regulator is a mixture of CeCl3·7H2O and LaCl3·7H2O in a mass ratio of 1:

1.

10. The use according to claim 8, characterized in that: In step 3), the argon pressure was maintained at 0.1~0.3MPa during the three refining processes; the graphite rotor speed was 300~350R / min.

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