Preparation method of 2A14 aluminum alloy square ingot

Abstract

The application discloses a preparation method of 2A14 aluminum alloy square ingot and belongs to the technical field of aluminum alloy. The preparation method comprises the following steps: (1) mixing and smelting original aluminum ingot, AlCu40, AlMn15, AlSi20 intermediate alloy and Mg ingot to obtain a melt; (2) sequentially performing in-furnace purification and online purification on the melt to obtain a purified melt; (3) performing grain refinement on the purified melt, wherein the grain refinement is performed by using AlTi5B1 wire, and the addition amount is 1.8-2.2 kg / t; (4) performing casting on the melt after the grain refinement, wherein the casting speed is 45-65 mm / min, the water flow is 40-70 m 3 / h / roots; and (5) performing homogenization heat treatment on the casting product to obtain a 2A14 aluminum alloy square ingot. The method and the ingot composition are jointly optimized, so that a surface flat, grid-rib basically straight grid-shaped product can be obtained after milling of a 2A14 aluminum alloy finished plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy, and particularly relates to a preparation method of 2A14 aluminum alloy square ingot. BACKGROUND

[0002] Chemical milling (chemical milling) is a processing technology that corrodes and dissolves the surface of a metal by a chemical solution. It removes the surface metal by using the corrosion of the solution to obtain the required shape and size. This processing method does not require mechanical cutting force, and is particularly suitable for removing a large amount of material, processing complex shapes and thin-walled structural parts. Chemical milling is widely used in the aerospace industry, such as the processing of large thin-walled parts such as the leading edge of an aircraft wing, the body wall plate, and the variable-thickness skin. These parts are usually made of thick plates as blanks, and are processed into thin-walled parts with complex curved surfaces and pits, grids, and ribs on the surface by chemical milling.

[0003] 2A14 aluminum alloy is a material belonging to hard aluminum alloy, and the main chemical components include zinc, iron, magnesium, aluminum and the like. The 2A14 aluminum alloy has good machinability, good resistivity, spot welding and seam welding performance, and in addition, has excellent mechanical properties, corrosion resistance and processability, and therefore is widely used in the fields of aerospace, national defense, sports equipment, automobiles and rail transportation.

[0004] However, in the preparation process of the 2A14 alloy square ingot, the 2A14 alloy liquid contains Mn, Cu alloy elements and impurity element Fe, and Al6(CuFeMn) compound phases are formed through eutectic reaction in the solidification process. The compound phases exist at the grain boundaries of the adjacent grains in the microstructure of the ingot, and will be converted into Al(CuMnFe)Si phases after homogenization process. The electrode potential of the Al(CuMnFe)Si phases is obviously different from that of the base metal, which will form a primary cell effect in the corrosion medium, and cause non-uniform corrosion. If the prepared square ingot has aggregated compound phases (Al(CuMnFe)Si phases), the square ingot will have a local string aggregation phenomenon of the Al(CuMnFe)Si phases along the rolling deformation direction. In the plate chemical milling process, the chemical milling defects such as pits, grid ribs and bending will be formed along with the aggregation of the compound, which cannot meet the chemical milling requirements.

[0005] Therefore, it is of great significance to develop a new type of 2A14 aluminum alloy square ingot preparation method to reduce the content or size of the Al(CuMnFe)Si phases, so as to reduce the string aggregation phenomenon in the plate and improve the quality of the plate chemical milling. SUMMARY

[0006] Therefore, the present application aims to provide a preparation method of 2A14 aluminum alloy square ingot.

[0007] To achieve the above object, the present application adopts the following technical solutions:

[0008] The present application provides a preparation method of 2A14 aluminum alloy square ingot, comprising the following steps:

[0009] (1) mixing and melting raw aluminum ingot, AlCu40, AlMn15, AlSi20 intermediate alloy and Mg ingot to obtain a melt;

[0010] (2) sequentially performing in-furnace purification and online purification on the melt to obtain a purified melt;

[0011] (3) performing grain refinement on the purified melt, wherein the grain refinement uses AlTi5B1 wire, and the addition amount is 1.8-2.2 kg / t;

[0012] (4) performing casting on the melt after grain refinement, wherein the casting speed is 45-65 mm / min, and the water flow rate is 40-70 m 3 / h / rod;

[0013] (5) performing homogenization heat treatment on the casting product to obtain a 2A14 aluminum alloy square ingot;

[0014] The 2A14 aluminum alloy square ingot comprises the following components:

[0015] Si 0.70%-1.10%, Fe≤0.15%, Cu 3.95%-4.20%, Mn 0.4%-1.0%, Mg 0.45%-0.75%, Ti≤0.05%, Ni<0.10, Zn≤0.30, and the balance is Al.

[0016] The present application jointly optimizes the preparation method and the components of the 2A14 aluminum alloy square ingot, so that the prepared 2A14 aluminum alloy square ingot can obtain a grid-shaped product with a smooth surface and straight grid ribs after milling.

[0017] The joint optimization reduces the content of Cu, Mn and Fe in the prepared 2A14 aluminum alloy square ingot, thereby reducing the formation of compound phases (Al(CuMnFe)Si phases).

[0018] In the 2A14 aluminum alloy square ingot, preferably, the content of Si is 0.80%-1.00%; more preferably, the content of Si is 0.88%, 0.85% or 0.87%.

[0019] Preferably, the Fe content is 0.05% to 0.08%; more preferably 0.07% or 0.06%.

[0020] Preferably, the Cu content is 3.90% to 4.00%; more preferably 3.98%, 3.92% or 4.00%.

[0021] Preferably, the Mn content is 0.60% to 0.80%; more preferably 0.70% or 0.68%.

[0022] Preferably, the Mg content is 0.50% to 0.60%; more preferably 0.60%, 0.59% or 0.57%.

[0023] Preferably, the Ti content is 0.02%;

[0024] Preferably, the Ni content is 0.01%;

[0025] Preferably, the Zn content is 0.02% to 0.04%; more preferably 0.04% or 0.02%.

[0026] Further preferably, the 2A14 aluminum alloy square ingot comprises the following components:

[0027] Si 0.88%, Fe 0.07%, Cu 3.98%, Mn 0.70%, Mg 0.60%, Ni 0.01%, Zn 0.04%, Ti 0.02%, and the balance being Al.

[0028] Alternatively, further preferably, the 2A14 aluminum alloy square ingot comprises the following components:

[0029] Si 0.85%, Fe 0.06%, Cu 3.92%, Mn 0.68%, Mg 0.59%, Ni 0.01%, Zn 0.02%, Ti 0.02%, and the balance being Al.

[0030] Alternatively, further preferably, the 2A14 aluminum alloy square ingot comprises the following components:

[0031] Si 0.87%, Fe 0.06%, Cu 4.00%, Mn 0.70%, Mg 0.57%, Ni 0.01%, Zn 0.02%, Ti 0.02%, and the balance being Al.

[0032] Preferably, in the step (4), the temperature of the aluminum liquid at the end of the flow plate is 695 to 720°C, and the temperature of the cooling water is 18 to 30°C.

[0033] Preferably, the temperature of the homogenization heat treatment in step (5) is 495-505℃, and the holding time is 24-30h.

[0034] Preferably, the temperature of the melting in step (1) is 720-760℃.

[0035] Preferably, the in-furnace purification in step (2) is selected from one or more of artificial refining, HD2000 refining, IRMA refining, and snorkel refining.

[0036] Preferably, the on-line purification in step (2) is selected from two-stage double-rotor rotary degassing and double-stage filtration.

[0037] The preparation method of the present application enables the compound phase in the 2A14 aluminum alloy square ingot to be small in size, dispersed in distribution, and free of obvious string-shaped compound formation.

[0038] The string shape of the string-shaped compound refers to the shape feature of the compound after a series of aggregation. Specifically, the string-shaped compound is formed by breaking and deforming the large compound phase (Al(CuMnFe)Si phase) in the ingot structure along the rolling direction during deformation.

[0039] Compared with the prior art, the preparation method of the 2A14 aluminum alloy square ingot provided by the present application comprises the following steps: (1) mixing and melting raw aluminum ingots, AlCu40, AlMn15, AlSi20 intermediate alloys, and Mg ingots to obtain a melt; (2) sequentially performing in-furnace purification and on-line purification on the melt to obtain a purified melt; (3) performing grain refinement on the purified melt, wherein the grain refinement is performed using AlTi5B1 wire, and the addition amount is 1.8-2.2kg / t; (4) casting the grain-refined melt, wherein the casting speed is 45-65mm / min, the water flow rate is 40-70m 3 / h / roots; and (5) performing homogenization heat treatment on the casting product to obtain a 2A14 aluminum alloy square ingot; the 2A14 aluminum alloy square ingot comprises the following components: Si 0.70%-1.10%, Fe≤0.15%, Cu 3.95%-4.20%, Mn 0.4%-1.0%, Mg 0.45%-0.75%, Ti≤0.05%, Ni<0.10, Zn≤0.30, and the balance being Al. The joint optimization of the preparation method and the components of the 2A14 aluminum alloy square ingot enables the 2A14 aluminum alloy finished plate prepared by the method to have a smooth surface and a grid-shaped product with substantially straight grid ribs after milling, and better meets the industrial demand. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1Microstructure diagrams of the 2A14 aluminum alloy square ingot and the plate thereof prepared in Example 1, wherein a diagram is a microstructure diagram of the ingot under an electron microscope at 50 times magnification, b diagram is a microstructure diagram of the ingot at 200 times magnification, and c diagram is a microstructure diagram of the plate at 50 times magnification;

[0041] Figure 2 Microstructure diagrams of the 2A14 aluminum alloy square ingot and the plate thereof prepared in Comparative Example 1, wherein a diagram is a microstructure diagram of the ingot under an electron microscope at 50 times magnification, b diagram is a microstructure diagram of the ingot at 200 times magnification, and c diagram is a microstructure diagram of the plate at 50 times magnification. DETAILED DESCRIPTION

[0042] In order to further illustrate the present application, the preparation method of the 2A14 aluminum alloy square ingot provided by the present application is described in detail below in combination with examples.

[0043] Example 1

[0044] Preparation of 2A14 aluminum alloy square ingot

[0045] The preparation process comprises, in sequence, alloy batching, alloy smelting to obtain a melt, in-furnace purification of the melt, online purification of the melt, grain refinement of the purified melt, casting of the grain-refined melt, and homogenization treatment, to prepare the 2A14 aluminum alloy square ingot.

[0046] Alloy batching: raw aluminum ingots, AlCu40, AlMn15, AlSi20 intermediate alloys, and Mg ingots are used as raw materials, and Cu element is batched at 3.95-4.20%, Mn element is batched at 0.40-1.0%, Mn element is batched at 0.40-1.0%, and Mg element is batched at 0.45-0.75%. In the present embodiment, the raw aluminum ingots are preferably of Al content of 99.90% and above in order to control the Fe content; AlCu40, AlMn15, and AlSi20 are preferably intermediate alloys with small-sized Al2Cu, Al6Mn, and coarse-grained silicon compounds and uniform distribution.

[0047] Alloy smelting: In the present embodiment, the raw aluminum ingots, AlCu40, AlMn15, and AlSi20 are added to a smelting furnace, and after complete melting into an aluminum alloy liquid, the Mg ingot is added in a pressing manner when the temperature is raised to 720-745°C, so as to reduce burning loss, and the reaction time is not less than 15 min. The temperature is controlled at 720-760°C during the smelting process.

[0048] In-furnace purification: In-furnace artificial refining, HD2000 refining, IRMA refining, and snorkel refining can be used. In the present embodiment, snorkel refining is preferred. The snorkel is installed at the bottom of the holding furnace, and the refining gas is Ar gas. The gas flow rate is 8-20 L / min / block, and preferably 15-18 L / min / block.

[0049] Grain refinement: In the present embodiment, AlTi5B1 wire is used for online refinement. The addition amount of the refining agent is 2.2 kg / t, and the addition position is before double-rotor degassing.

[0050] Online purification: In the present embodiment, two-stage double-rotor degassing is preferred for online degassing. Double-stage filtration is used for online filtration. The first stage uses a ceramic filter plate with a precision of 40PPi, and the second stage uses a ceramic filter plate with a precision of 50PPi.

[0051] Casting process: The ingot thickness is 400 mm, and the casting speed is 59-61 mm / min in the present embodiment. The water flow rate is 65-69 m 3 / h / root, and the water temperature is 28°C. The temperature at the end of the flow disc is 695°C-715°C. With these parameters, the ingot is completely formed.

[0052] Soaking process: In the present embodiment, single-stage soaking is used. The soaking temperature is 495-500 (±5) °C, preferably 500 ± 5 °C, and more preferably 500 ± 3 °C. The soaking time is 15-25 h, and preferably 24 h.

[0053] The composition of the 2A14 aluminum alloy square ingot obtained by the above preparation method is: Si 0.88%, Fe 0.07%, Cu 3.98%, Mn 0.70%, Mg 0.60%, Ni 0.01%, Zn 0.04%, Ti 0.02%, and the balance is Al.

[0054] Example 2

[0055] Preparation of 2A14 aluminum alloy square ingot

[0056] Grain refinement: In the present embodiment, AlTi5B1 wire is used for online refinement. The addition amount of the refining agent is 1.9 kg / t.

[0057] Casting process: The casting thickness is 400 mm, and the casting speed is preferably 52-54 mm / min. In the present embodiment, the water flow rate is 55-58 m 3 / h / root, and the water temperature is 21°C. The temperature at the end of the flow disc is 700°C-710°C. With these parameters, the ingot is completely formed.

[0058] The remaining preparation process is the same as that of Example 1.

[0059] The composition of the 2A14 aluminum alloy square ingot obtained by the above preparation method is: Si 0.85%, Fe 0.06%, Cu 3.92%, Mn 0.68%, Mg 0.59%, Ni 0.01%, Zn 0.02%, Ti 0.02%, and the balance is Al.

[0060] Example 3

[0061] Casting process: the thickness of the ingot is 400 mm, the casting speed of the example is 46-48 mm / min, the water flow of the example is 52-55 m 3 / h / root. With this parameter, the ingot is fully formed.

[0062] The rest of the preparation process is the same as that of Example 1.

[0063] The composition of the 2A14 aluminum alloy square ingot obtained by the above preparation method is: Si 0.87%, Fe 0.06%, Cu 4.00%, Mn 0.70%, Mg 0.57%, Ni 0.01%, Zn 0.02%, Ti 0.02%, and the balance is Al.

[0064] Comparative Example 1

[0065] Grain refinement: AlTi5B1 wire is used for online refinement in this example, and the addition amount of the refiner is 1.8-2.2 kg / t

[0066] Casting process: the thickness of the ingot is 400 mm, the casting speed of the example is 46-48 mm / min, the water flow of the example is 52-55 m 3 / h / root. With this parameter, the ingot is fully formed.

[0067] The rest of the preparation process is the same as that of Example 1.

[0068] The composition of the 2A14 aluminum alloy square ingot obtained by the above preparation method is: Si 0.89%, Fe 0.17%, Cu 3.94%, Mn 0.78%, Mg 0.56%, Ni 0.01%, Zn 0.01%, Ti 0.02%, and the balance is Al.

[0069] Comparative Example 2

[0070] Grain refinement: AlTi5B1 wire is used for online refinement in this example, and the addition amount of the refiner is 1.2 kg / t.

[0071] Casting process: the thickness of the ingot is 400 mm, the casting speed of the example is 46-48 mm / min, the water flow of the example is 52-55 m 3 / h / root. With this parameter, the ingot is fully formed.

[0072] The rest of the preparation process is the same as that of Example 1.

[0073] The composition of the 2A14 aluminum alloy square ingot prepared by the above preparation method is: Si 0.89%, Fe 0.08%, Cu 3.95%, Mn 0.72%, Mg 0.60%, Ni 0.01%, Zn 0.02%, Ti 0.02%, and the balance is Al.

[0074] The compound size of the 2A14 alloy ingot prepared in the above Examples 1-3 is smaller and more dispersed, and the compound size of the 2A14 alloy ingot prepared in the above Comparative Example 1 is larger and less dispersed. Figure 1 The contrast between FIGS. b and c shows that the compound size of the 2A14 alloy ingot of Example 1 is smaller than that of Comparative Example 1, and the compound distribution of Example 1 is more dispersed than that of Comparative Example 1. Figure 2 The contrast between FIGS. b and c shows that the compound size of the 2A14 alloy ingot of Example 1 is smaller than that of Comparative Example 1, and the compound distribution of Example 1 is more dispersed than that of Comparative Example 1.

[0075] As shown in FIGS. a and c, the 2A14 aluminum alloy square ingot prepared in Example 1 is rolled to obtain a 2A14 aluminum alloy plate, and the plate structure is better than that of the 2A14 aluminum alloy plate obtained by rolling deformation of the 2A14 aluminum alloy square ingot prepared in Comparative Example 1, which has the advantages of small compound phase size, dispersed distribution, and no obvious string-shaped compound, which indicates that the 2A14 aluminum alloy square ingot prepared in Example 1 does not contain large-size compound phases (because the compound phase size of the ingot prepared in Example 1 is small and does not aggregate at the junction to form large compound phases), that is, the compound phase (Al(CuMnFe)Si phase) contained therein is smaller than that of Comparative Example 1. Figure 1 Figure 2 The 2A14 aluminum alloy square ingot prepared in the above Examples 1-3 is rolled to obtain a 2A14 aluminum alloy plate, and the obtained plate is respectively subjected to chemical milling, to test the improvement of the preparation method of the present application on the 2A14 aluminum alloy plate.

[0076] The above chemical milling is surface treated with 40%-60% NaOH solution and 20%-30% HNO3 solution for 60-120 min, and then subjected to glue brushing, type carving and other operations, and then subjected to chemical milling with a mixed solution of 50-90 g / L Al and 60-130 g / L NaOH, to obtain a grid-shaped product with a flat surface, no local pits, and straight grid ribs, which is qualified for chemical milling.

[0077] The above chemical milling is surface treated with 40%-60% NaOH solution and 20%-30% HNO3 solution for 60-120 min, and then subjected to glue brushing, type carving and other operations, and then subjected to chemical milling with a mixed solution of 50-90 g / L Al and 60-130 g / L NaOH, to obtain a grid-shaped product with a flat surface, no local pits, and straight grid ribs, which is qualified for chemical milling.

[0078] ​The 2A14 aluminum alloy ingot prepared by Comparative Examples 1 and 2 is rolled to obtain a 2A14 aluminum alloy plate. Since there are string-shaped compounds in the plate (the string-shaped refers to the shape characteristics of the compounds after a series of aggregation. Specifically, the string-shaped compound is formed by the crushing and deformation of large compound phases (Al(CuMnFe)Si phases) in the ingot structure along the rolling direction during the deformation process), after the above milling operation, there are local pits on the surface of the plate, and the grid ribs are not straight, which is not qualified for milling.

[0079] The above examples are only used to help understand the method of the present application and its core idea. It should be noted that for those skilled in the art, without departing from the principles of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A method for producing a 2A14 aluminum alloy square ingot, characterized by, It comprises the following steps: (1) mixing and smelting original aluminum ingot, AlCu40, AlMn15, AlSi20 intermediate alloy and Mg ingot to obtain a melt; (2) sequentially performing in-furnace purification and online purification on the melt to obtain a purified melt; (3) performing grain refinement on the purified melt, wherein the grain refinement adopts AlTi5B1 wire, and the addition amount is 1.8-2.2 kg / t; (4) casting the melt after grain refinement, wherein the casting speed is 45-65 mm / min, the water flow is 40-70 m 3 / h / root; (5) performing homogenization heat treatment on the casting product to obtain a 2A14 aluminum alloy square ingot; The 2A14 aluminum alloy square ingot comprises the following components: Si 0.70%-1.10%, Fe≤0.15%, Cu 3.95%-4.20%, Mn 0.4%-1.0%, Mg 0.45%-0.75%, Ti≤0.05%, Ni<0.10, Zn≤0.30, and the balance of Al; In the step (4), the flow disc end liquid aluminum temperature is 695-720℃, and the cooling water temperature is 18-30℃ during casting; The homogenization heat treatment temperature in the step (5) is 495-505℃, and the holding time is 24-30h.

2. The production method according to claim 1, characterized by, The smelting temperature in the step (1) is 720℃-760℃.

3. The preparation method according to claim 1, characterized in that, The in-furnace purification in the step (2) is selected from one or more of artificial refining, HD2000 refining, IRMA refining and air-lancing refining; The online purification in the step (2) is selected from two-stage double-rotor rotary degassing and double-stage filtration.

Images