A ZL114A casting alloy smelting process

Abstract

The present invention provides a high-performance ZL114A casting alloy smelting process. This process differs from conventional ZL114A alloy smelting processes and subverts traditional aluminum alloy smelting technology. It utilizes a five-stage resistance furnace process, including high-temperature purification, medium-temperature refinement, medium-temperature purification, metamorphism, and low-temperature degassing and purification. Titanium is added in the form of rod-shaped aluminum-titanium-boron wire during the medium-temperature refinement; a mixed refining agent of C2Cl6 and Al2O3 is wrapped in aluminum foil and pressed into the molten aluminum using a steel bell jar; strontium is added in the form of an AlSr10A master alloy during the metamorphism; and finally, high-purity argon is used for low-temperature composite refining. The ZL114A casting alloy produced using this process exhibits superior tensile strength, yield strength, elongation δ5 at 5% tensile deformation, and gas content compared to castings produced using conventional processes.

Description

Technical Field

[0001] The invention belongs to the field of aluminum alloy smelting, and in particular relates to a high-performance and high-quality casting alloy smelting process. Background Art

[0002] Aluminum alloy is a common lightweight metal material, among which ZL114A is a casting alloy with high strength and toughness. Due to its good fluidity and filling capacity, its internal structure is denser than other cast aluminum alloys. It has been widely used in missile casings and casing castings. It is also widely used in the casting molding process of various large-scale structural products in industries such as aviation, aerospace, automobiles, and ships.

[0003] In order to ensure high mechanical properties, the ZL114A aluminum alloy material used is generally prepared in a vacuum test furnace using refined aluminum (Al≥99.85%). However, in the actual production process, the operation is relatively complicated, the smelting time is long, and the alloy is not easy to absorb air, resulting in low production efficiency, poor quality of the obtained alloy, and the control of gas content, light impurities and impurity elements in the alloy is not ideal. Therefore, it is urgent to develop a smelting method for ZL114A alloy to solve the problems in the prior art. The traditional casting aluminum silicon alloy smelting process cannot meet the needs of high-performance and high-quality castings. At the same time, due to the high silicon content in the alloy, if no deterioration measures are taken, the alloy plasticity will be poor, which limits its use in certain high-strength, high-pressure oil pipeline castings. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a high-performance ZL114A casting alloy smelting process. This process is different from the traditional ZL114A alloy smelting process and subverts the traditional aluminum alloy smelting technology. It adopts a five-stage treatment process in an electric resistance furnace, including high-temperature purification, medium-temperature refinement, medium-temperature purification, metamorphic treatment and low-temperature degassing purification. The technical features are as follows:

[0005] A high-performance ZL114A casting alloy smelting process comprises the following steps:

[0006] S1. High temperature purification: Heat the charge to melt and stir; heat the aluminum liquid to 800℃~830℃ for superheat treatment and stir again;

[0007] S2. Medium temperature refinement: cool the alloy liquid to 740-760°C, add titanium in the form of rod-shaped aluminum titanium boron wire, and stir after the aluminum titanium boron wire is completely melted;

[0008] S3, medium temperature purification: the alloy liquid temperature is lowered to 710-730 ℃ for purification, and the alloy liquid is refined with a mixed refining agent of C2Cl6 and Al2O3. The mixed refining agent is wrapped with aluminum foil and pressed into the aluminum liquid with a steel bell jar;

[0009] S4. Modification treatment: After refining, the alloy liquid temperature is controlled to 700-710°C, and strontium is added slowly in the form of AlSr10A master alloy. After the AlSr10A master alloy is completely melted, stir;

[0010] S5. Suspension treatment: let the alloy liquid stand, add titanium again in the form of rod-shaped aluminum titanium boron wire, melt and stir;

[0011] S6. Low-temperature composite refining: reduce the alloy liquid temperature to 690-710℃ and refine it with high-purity argon; finally, use vacuum equipment to perform vacuum treatment.

[0012] Preferably, in step S1, the stirring time is 12 min to 15 min; the overheating time is 20 min to 45 min; and the re-stirring time is 15 to 20 min.

[0013] Preferably, the mass of titanium added in step S2 is 0.10-0.17% of the total mass of the aluminum liquid.

[0014] Preferably, in the step S3, C2Cl6 is analytically pure; and the mesh size of Al2O3 is greater than 300 mesh.

[0015] Preferably, in step S3, the mass ratio of C2Cl6 to Al2O3 is 1:2.5-3; the mass of C2Cl6 is 5-7‰ of the total mass of the aluminum liquid.

[0016] Preferably, the total weight of the mixed refining agent wrapped in aluminum foil in step S3 is controlled to be 400-500 g.

[0017] Preferably, in step S3, the aluminum is pressed into the crucible to a depth of 100 to 150 mm from the bottom surface; and the refining time is 20 to 30 min.

[0018] Preferably, in step S4, the mass of strontium is 0.04-0.06% of the total mass of the aluminum liquid; and the stirring time is 5 minutes.

[0019] Preferably, the standing time in step S5 is 15 to 20 minutes; the mass of the added titanium is 0.05-0.08% of the total mass of the aluminum liquid; and the stirring time is 5 minutes.

[0020] Preferably, in step S6, the argon flow rate is 15 L / min, the argon blowing time is 20 min, the vacuum condition is 600-1000 Pa, and the vacuum treatment is 5-15 min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention provides a high-performance ZL114A casting alloy smelting process, which subverts the traditional aluminum alloy smelting technology and adopts a five-stage treatment process in an electric resistance furnace, including high-temperature purification (≥830℃), medium-temperature refinement (740-760℃), medium-temperature purification (710-720℃), metamorphic treatment, and low-temperature (690-710℃) degassing and purification steps, which greatly improves the mechanical properties of the casting.

[0023] 2. The ZL114A casting alloy obtained by the process of the present invention is superior to the traditional process in tensile strength, yield strength and elongation, and the gas content of the casting is also significantly reduced.

[0024] 3. In the low-temperature composite refining step, argon is introduced into the alloy body to form bubbles. The hydrogen in the melt diffuses into these bubbles under the action of the partial pressure difference and is removed as the bubbles float upward to achieve the purpose of degassing. At the same time, the bubbles can also absorb some oxide inclusions during the floating process to play a role in removing impurities. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to specific embodiments.

[0026] The following examples are provided to illustrate the present invention but are not intended to limit the scope of the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the methods, steps or conditions of the present invention are within the scope of the present invention.

[0027] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art; unless otherwise specified, the reagents used in the examples are commercially available.

[0028] Example 1

[0029] Melting high performance ZL114A casting alloy

[0030] 1. High-temperature purification: Power on to heat up the furnace to melt the charge, and stir for 15 minutes; heat the aluminum liquid to 830℃ for overheating treatment, the overheating treatment time is 45 minutes, and then stir with a stirring spoon for 20 minutes;

[0031] 2. Medium temperature refinement: Cool the alloy liquid to 760℃, add 0.17% titanium, Ti is added in the form of rod-shaped aluminum titanium boron wire (AlTi5BA), and stir for 15min after the aluminum titanium boron wire is completely melted;

[0032] 3. Medium-temperature purification: The alloy liquid temperature is lowered to 730℃ for purification. The alloy liquid is refined with a mixture of C2Cl6 and Al2O3. The C2Cl6 is analytical grade, the Al2O3 mesh is 350 mesh, the mass ratio of Al2O3 to C2Cl6 is 3:1, and the total amount of C2Cl6 is 7‰ of the molten aluminum liquid. The mixed refining agent is wrapped in aluminum foil, and the weight of one package is controlled at 500g. The mixed refining agent is pressed into the aluminum liquid with a steel bell jar. The pressing depth is 150mm from the bottom of the crucible. The refining time is 30min.

[0033] 4. Modification treatment: After refining, control the alloy liquid temperature to 710℃, add 0.06% strontium, strontium is added in the form of AlSr10A master alloy, use a stirring spoon to hold the AlSr10A master alloy and slowly add it into the alloy liquid. Stir for 5min after the AlSr10A master alloy is completely melted;

[0034] 5. Suspension treatment: let the alloy stand for 20 minutes, add 0.08% titanium in the form of rod-shaped aluminum titanium boron wire, and stir for 5 minutes;

[0035] 6. Low-temperature composite refining: Cool the alloy liquid to 690°C and refine it with high-purity argon (argon flow rate: 15L / min, blowing for 20min); finally, use vacuum equipment to perform vacuum treatment: 600~1000Pa, treatment for 5~15min.

[0036] Example 2

[0037] Melting high performance ZL114A casting alloy

[0038] 1. High-temperature purification: Power on to heat up the furnace to melt the charge, and stir for 12 minutes; heat the aluminum liquid to 800℃ for overheating treatment, the overheating treatment time is 20 minutes, and then stir with a stirring spoon for 15 minutes;

[0039] 2. Medium temperature refinement: Cool the alloy liquid to 740℃, add 0.10% titanium, Ti is added in the form of rod-shaped aluminum titanium boron wire (AlTi5BA), and stir for 15min after the aluminum titanium boron wire is completely melted;

[0040] 3. Medium-temperature purification: The alloy liquid temperature is lowered to 710℃ for purification. The alloy liquid is refined with a mixture of C2Cl6 and Al2O3. The C2Cl6 is analytical grade, the Al2O3 mesh is 400 mesh, the mass ratio of Al2O3 to C2Cl6 is 2.5:1, and the total amount of C2Cl6 is 5‰ of the molten aluminum liquid. The mixed refining agent is wrapped in aluminum foil, and the weight of one package is controlled at 400g. The mixed refining agent is pressed into the aluminum liquid with a steel bell jar. The pressing depth is 100mm from the bottom of the crucible. The refining time is 20min.

[0041] 4. Modification treatment: After refining, control the alloy liquid temperature to 700℃, add 0.04% strontium, strontium is added in the form of AlSr10A master alloy, use a stirring spoon to hold the AlSr10A master alloy and slowly add it into the alloy liquid. After the AlSr10A master alloy is completely melted, stir for 5min;

[0042] 5. Suspension treatment: let the alloy stand for 15 minutes, add 0.05% titanium in the form of rod-shaped aluminum titanium boron wire, and stir for 5 minutes;

[0043] 6. Low-temperature composite refining: Cool the alloy liquid to 690°C and refine it with high-purity argon (argon flow rate: 15L / min, blowing for 20min); finally, use vacuum equipment to perform vacuum treatment: 600~1000Pa, treatment for 5~15min.

[0044] Experimental Example 1

[0045] Investigate the performance comparison of smelting high performance ZL114A casting alloy and traditional processing technology

[0046] The high performance ZL114A casting alloy prepared in Example 1 was compared with the ZL114A casting alloy obtained by the conventional process in terms of tensile strength σb, yield strength σ0.2, elongation δ5 when the casting was tensilely deformed to 5%, and gas content at the same position.

[0047] σb, σ0.2, and δ5 were tested in accordance with GB / T 228-2010, and the gas content was tested in accordance with GB / T 20975.30-2019. The results are shown in Table 1:

[0048] Table 1 Comparison of properties of castings treated with conventional process and castings of Example 1

[0049] Craftsmanship σb σ0.2 δ5(%) Gas content Traditional processing technology 340 270 5 0.12~0.21ml / 100g Example 1 365 285 8 0.09ml~0.2ml / 100g

[0050] The results show that the ZL114A casting alloy obtained by smelting the process of the present invention is superior to those obtained by the traditional process in terms of tensile strength, yield strength and elongation, and the gas content of the casting is also significantly reduced. This shows that the mechanical properties of the castings produced by the high-performance ZL114A casting alloy smelting process provided by the present invention are far superior to those prepared by the traditional process.

[0051] The above is only a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiment. For those skilled in the art, improvements and modifications obtained without departing from the technical concept of the present invention should also be considered as the scope of protection of the present invention.

Claims

1. A ZL114A casting alloy smelting process, characterized in that: The steps include: S1. High temperature purification: Heat up to melt the charge and stir; heat the aluminum liquid to 800℃~830℃ for superheat treatment and then stir; S2. Medium temperature refinement: cool the alloy liquid to 740-760°C, add titanium in the form of rod-shaped aluminum titanium boron wire, and stir after the aluminum titanium boron wire is completely melted; S3, medium temperature purification: the alloy liquid temperature is lowered to 710-730 ℃ for purification, and the alloy liquid is refined with a mixed refining agent of C2Cl6 and Al2O3. The mixed refining agent is wrapped with aluminum foil and pressed into the aluminum liquid with a steel bell jar; The mass ratio of C2Cl6 to Al2O3 is 1:2.5-3; the mass of C2Cl6 is 5-7‰ of the total mass of the aluminum liquid; the depth of the aluminum foil pressed into the crucible is 100-150 mm; S4. Modification treatment: After refining, the alloy liquid temperature is controlled to 700-710°C, and strontium is added slowly in the form of AlSr10A master alloy. After the AlSr10A master alloy is completely melted, stir; S5. Suspension treatment: let the alloy liquid stand, add titanium again in the form of rod-shaped aluminum titanium boron wire, melt and stir; S6. Low-temperature composite refining: reduce the alloy liquid temperature to 690-710°C and refine with high-purity argon; finally, use vacuum equipment to perform vacuum treatment; wherein, the argon flow rate is 15L / min, the argon blowing time is 20min; the vacuum condition is 600-1000Pa, and the vacuum treatment time is 5-15min.

2. The ZL114A casting alloy smelting process according to claim 1, characterized in that: The superheat treatment time in step S1 is 20 min to 45 min.

3. The ZL114A casting alloy smelting process according to claim 1, characterized in that: The mass of titanium added in step S2 is 0.10-0.17% of the total mass of the aluminum liquid.

4. The ZL114A casting alloy smelting process according to claim 1, characterized in that: In the step S3, C2Cl6 is analytically pure; and the mesh size of Al2O3 is greater than 300 mesh.

5. The ZL114A casting alloy smelting process according to claim 1, characterized in that: In the step S3, the total weight of the mixed refining agent wrapped in aluminum foil is controlled to be 400-500 g.

6. The ZL114A casting alloy smelting process according to claim 1, characterized in that: The refining time in the S3 step is 20-30 minutes.

7. The ZL114A casting alloy smelting process according to claim 1, characterized in that: The mass of strontium in step S4 is 0.04-0.06% of the total mass of the aluminum liquid.

8. The ZL114A casting alloy smelting process according to claim 1, characterized in that: The standing time in step S5 is 15 to 20 minutes; the mass of the added titanium is 0.05 to 0.08% of the total mass of the aluminum liquid.