CN112708807A - 4XXX series aluminum alloy and preparation method thereof - Google Patents

Abstract

The application relates to a 4XXX series aluminum alloy and a preparation method thereof. The 4XXX series aluminum alloy comprises the following components in percentage by mass: 11.5% -12.5% silicon; 4.0% -5.0% of copper; 0.52-0.6% magnesium; less than or equal to 0.01% manganese; less than or equal to 0.02% titanium; less than or equal to 0.02% chromium; less than or equal to 0.15% iron; the balance being aluminum. The preparation method of the 4XXX series aluminum alloy comprises the following steps: weighing raw materials; smelting the raw materials until the raw materials are completely melted, and adding a nucleating agent into the melted raw materials; standing the raw materials, and performing online degassing and two-stage filtration on the raw materials after standing; casting the raw material by adopting a hot-top horizontal casting process to form a bar stock; homogenizing the bar stock and cooling; and (5) extruding and forming a bar stock. By adding the nucleating agent and optimizing the components of the 4XXX series aluminum alloy, the method improves the capability of the alloy to precipitate a strengthening phase, thereby improving the strength of the product.

Description

4XXX series aluminum alloy and preparation method thereof

Technical Field

The application relates to an aluminum alloy, in particular to a 4XXX series aluminum alloy and a preparation method thereof.

Background

The 4XXX series aluminum alloy is an aluminum alloy taking silicon as a main alloy element, and the series alloy is mainly used for manufacturing aluminum alloy forgings because the series alloy has high silicon content, low melting point, good melt fluidity and easy feeding and does not cause brittleness of final products.

In the course of implementing the present application, the applicant has found that the prior art has at least the following problems:

the 4XXX series aluminum alloy in the prior art has lower tensile strength and cannot meet the requirements of the prior art, so that a 4XXX series aluminum alloy and a preparation method thereof are urgently needed to prepare an aluminum alloy with higher tensile strength.

Disclosure of Invention

In order to solve the technical problems in the prior art, embodiments of the present application provide a 4XXX series aluminum alloy and a preparation method thereof. The specific technical scheme is as follows:

in a first aspect, a 4XXX series aluminum alloy is provided, the 4XXX series aluminum alloy including the following compositions in percentage by mass: 11.5% -12.5% silicon; 4.0% -5.0% of copper; 0.52-0.6% magnesium; less than or equal to 0.01% manganese; less than or equal to 0.02% titanium; less than or equal to 0.02% chromium; less than or equal to 0.15% iron; the balance being aluminum.

In a first possible implementation form of the first aspect, the 4 XXX-series aluminum alloy further includes, in mass percent, less than or equal to 0.05% of other elements.

In a second aspect, there is provided a method of making a 4XXX series aluminum alloy, comprising the steps of: weighing the 4XXX series aluminum alloy of any of the above first aspects; smelting the raw materials until the raw materials are completely melted, and adding a nucleating agent into the melted raw materials to ensure that the nucleating agent forms a large amount of dispersed artificially-made non-spontaneous crystal nuclei in the raw materials so as to obtain fine casting crystal grains; standing the raw materials, and performing online degassing and two-stage filtration on the raw materials after standing; casting the raw material by adopting a hot-top horizontal casting process to form a bar stock; homogenizing the bar stock and cooling; and (5) extruding and forming a bar stock.

In a first possible implementation manner of the second aspect, the smelting temperature of the smelting raw material is 720-770 ℃.

In a second possible implementation of the second aspect, the weight of the nucleating agent relative to the feedstock is 3 kg/ton.

In a third possible implementation manner of the second aspect, the casting speed of the casting raw material is 125-135mm/min, and the cooling water flow rate is 6500-7200L/min.

In a fourth possible implementation manner of the second aspect, the casting of the raw material further comprises the following steps: preheating equipment used in the casting process, and baking the launder, the degassing tank, the filter box and the die plate.

In a fifth possible implementation manner of the second aspect, the heating temperature of the homogenization treatment bar is 470-490 ℃, and the holding time is 3.5 h.

In a sixth possible implementation form of the second aspect, the method of cooling the bar stock is air cooling.

In a seventh possible implementation manner of the second aspect, the extrusion forming of the bar stock further comprises the following steps: and (4) placing the bar stock in an extruder heating furnace for preheating.

Compared with the prior art, the application has the advantages that:

according to the 4XXX series aluminum alloy and the preparation method thereof, the nucleating agent is added into the aluminum liquid, so that a large number of dispersed artificially-manufactured non-spontaneous crystal nuclei are formed in the aluminum liquid, and therefore fine casting crystal grains can be obtained. In addition, this application is still through preheating the used equipment of casting before the casting, toasts chute, deaerating tank, rose box, die disc etc. and reduces temperature loss, has optimized the casting condition.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic flow chart illustrating the steps of a method of making a 4XXX aluminum alloy according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In an embodiment of the present application, raw materials are weighed according to the mass percentage of a 4XXX aluminum alloy, and the raw materials comprise, by mass, 11.5% -12.5% of silicon (Si), 4.0% -5.0% of copper (Cu), 0.52% -0.6% of magnesium (Mg), less than or equal to 0.01% of manganese (Mn), less than or equal to 0.02% of titanium (Ti), less than or equal to 0.02% of chromium (Cr), less than or equal to 0.15% of iron (Fe), and the balance of aluminum (Al). Preferably, the mass percentage of the other elements is less than or equal to 0.05%.

Please refer to fig. 1, which shows a schematic flow chart of the steps of a method for preparing a 4XXX aluminum alloy according to an embodiment of the present application. Preparation method 1 for preparing 4XXX aluminum alloy from the above-weighed raw materials, the preparation method of 4XXX aluminum alloy comprises the following steps 101 to 104, wherein:

step 101, smelting raw materials and adding a nucleating agent. Adding the raw materials into a smelting furnace, executing a smelting process, setting the smelting temperature of the smelting furnace to be 720-770 ℃, smelting the raw materials until the raw materials are completely melted to form aluminum liquid, wherein the smelting temperature can be specifically set to be 720 ℃, 740 ℃ or 760 ℃, but not limited thereto. Then adding nucleating agent into the melted raw material to make the nucleating agent form a large amount of dispersed artificially-made non-spontaneous crystal nuclei (also called alterant) in the raw material and make the nucleating agent form a large amount of dispersed artificially-made non-spontaneous crystal nuclei in the molten aluminum, thereby obtaining fine casting crystal grains and further achieving the purpose of improving the material performance. Preferably, the nucleating agent is 3 kg/ton of raw material, i.e. 3kg of raw material is added to one ton of raw material/molten aluminum, but not limited thereto.

Step 102, online degassing and dual-stage filtering of the feedstock. Standing the refined raw material, and then performing online degassing and two-stage filtration on the raw material, wherein the online degassing and two-stage filtration mode is a conventional technical means of a person skilled in the art, and the details are not repeated herein. 125-135mm/min, cooling water flow rate of 6500-7200L/min

And 103, casting and forming a bar stock. Preheating equipment used in the casting process, baking a runner, a degassing tank, a filter box and a die disc, then adopting a hot-top horizontal casting process, casting the raw materials into a die, setting the casting speed to be 125-plus-135 mm/min, specifically to be 125mm/min, 130mm/min or 135mm/min, setting the cooling water flow to be 6500-plus-7200L/min, specifically to be 6500-plus-6800L/min, or 7200L/min, and forming a bar after the raw materials are cooled and solidified.

And step 104, homogenizing the bar stock and cooling. Carrying out homogenization treatment on the bar stock, setting the homogenization treatment temperature to be 470-490 ℃, specifically 470 ℃, 480 ℃ or 490 ℃, keeping the temperature for 3.5h, discharging the bar stock after the heat preservation is finished, and naturally cooling the bar stock;

and 105, extruding and forming a bar stock. And (3) placing the bar stock in an extruder heating furnace for preheating, then extruding and molding through a die, and naturally cooling the extruded bar stock in the air.

In the 4XXX aluminum alloy and the preparation method 1 thereof of the embodiment, the nucleating agent is added into the aluminum liquid, so that a large amount of dispersed artificially-produced non-spontaneous crystal nuclei are formed in the aluminum liquid, thereby obtaining fine casting crystal grains, and simultaneously, the capability of precipitating a strengthening phase from the alloy is improved by optimizing the components, homogenizing the process, preheating the blank in the extrusion process, cooling the product and other parameters, thereby improving the strength of the product. In addition, the casting equipment is preheated before casting, and the launder, the degassing tank, the filter box, the die disc and the like are baked, so that the temperature loss is reduced, and the casting conditions are optimized.

The beneficial effects of the 4XXX series aluminum alloys of the present application and methods for making the same are further described below in conjunction with specific examples and comparative examples.

Example 1

1. Weighing raw materials according to the mass percent of 4XXX aluminum alloy, wherein the raw materials comprise, by mass, 12.2% of Si, 4.2% of Cu, 0.58% of Mg, 0.005% of Mn, 0.008% of Ti, 0.0086% of Cr, 0.121% of Fe and the balance of Al.

2. Adding the weighed raw materials into a smelting furnace, smelting at the temperature of 720-770 ℃ to obtain an aluminum alloy melt, and adding a nucleating agent into the aluminum alloy melt;

3. electrically heating and baking the flow groove, the degassing box and the filter box mold disc, wherein the electric heating temperature is set to 850 ℃, when the temperature is baked to 740-;

4. performing a homogenization procedure, wherein the heating temperature is 470-;

5. cutting the cast rod to a required length, placing the cast rod in an extruder heating furnace for preheating, performing extrusion molding through a die, and testing the strength of the cast rod after solid solution and aging to be 490 MPa.

Example 2

1. Weighing raw materials according to the mass percent of 4XXX aluminum alloy, wherein the raw materials comprise 11.8 percent of Si, 4.5 percent of Cu, 0.57 percent of Mg, 0.0023 percent of Mn, 0.004 percent of Ti, 0.006 percent of Cr, 0.135 percent of Fe and the balance of Al.

2. Adding the weighed raw materials into a smelting furnace, smelting at the temperature of 720-770 ℃ to obtain an aluminum alloy melt, and adding a nucleating agent into the aluminum alloy melt;

3. electrically heating and baking the flow groove, the degassing box and the filter box mold disc, wherein the electric heating temperature is set to 850 ℃, when the temperature is baked to 740-;

4. performing a homogenization procedure, wherein the heating temperature is 470-;

5. cutting the cast rod to a required length, placing the cast rod in an extruder heating furnace for preheating, performing extrusion molding through a die, and testing the strength of the cast rod after solid solution and aging to be 487.9 MPa.

Comparative example

1. The method comprises the steps of selecting a commonly used 4-series aluminum alloy meeting the national standard in the prior art, specifically selecting a 4032 aluminum alloy, weighing raw materials according to the mass percent of the 4032 aluminum alloy, wherein the raw materials comprise 12.64% of Si, 0.75% of Cu, 1.13% of Mg, 0.03% of Mn, 0.003% of Ti, 0.005% of Cr, 0.31% of Fe, 0.62% of nickel (Ni) and the balance of Al.

2. Adding the weighed raw materials into a smelting furnace, and smelting and refining at 760 +/-5 ℃ to obtain an aluminum alloy melt;

3. electrically heating and baking the flow groove, the degassing box and the filter box mold disc, wherein the electric heating temperature is set to 850 ℃, when the temperature is baked to 740-;

4. performing a homogenization procedure, wherein the heating temperature is 470-;

5. cutting the cast rod to a required length, placing the cast rod in an extruder heating furnace for preheating, performing extrusion molding through a die, and testing the strength of the cast rod after solid solution and aging to be 397.4 MPa.

As is clear from the comparison of the tensile strength data of examples 1 and 2 with the tensile strength data of the comparative example, the tensile strength of the 4XXX aluminum alloy of the present application after casting can be about 490MPa, and under the same conditions, the tensile strength is much higher than that (397.4MPa) of the other 4 series aluminum alloys.

In summary, the present application provides a 4XXX series aluminum alloy and a preparation method thereof, wherein a nucleating agent is added into the aluminum liquid, so that the nucleating agent forms a large amount of dispersed artificially-produced non-spontaneous crystal nuclei in the aluminum liquid, thereby obtaining fine casting crystal grains, and simultaneously, the present application also improves the capability of the alloy to precipitate a strengthening phase by optimizing the components and homogenization process of the 4XXX series aluminum alloy, and parameters of blank preheating, product cooling and the like in the extrusion process, thereby improving the strength of the product. In addition, this application is still through preheating the used equipment of casting before the casting, toasts chute, deaerating tank, rose box, die disc etc. and reduces temperature loss, has optimized the casting condition.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims (10)

1. A4 XXX series aluminium alloy, characterized in that, the 4XXX series aluminium alloy comprises the following components by mass percent:

11.5% -12.5% silicon;

4.0% -5.0% of copper;

0.52-0.6% magnesium;

less than or equal to 0.01% manganese;

less than or equal to 0.02% titanium;

less than or equal to 0.02% chromium;

less than or equal to 0.15% iron;

the balance being aluminum.

2. The 4XXX series aluminum alloy of claim 1, wherein the 4XXX series aluminum alloy further includes, in the range of from 0.05% by weight or less, other elements.

3. A method for preparing a 4XXX series aluminum alloy, which is characterized by comprising the following steps:

weighing the 4XXX series aluminum alloy of any of claims 1-2;

smelting the raw materials to be completely molten, and adding a nucleating agent into the molten raw materials, so that the nucleating agent forms a large amount of dispersed artificially-made non-spontaneous crystal nuclei in the raw materials to obtain fine casting crystal grains;

standing the raw materials, and performing online degassing and two-stage filtration on the raw materials after standing;

casting the raw material by adopting a hot-top horizontal casting process to form a bar stock;

homogenizing the bar stock, and cooling;

and extruding and forming the bar stock.

4. The method of claim 3, wherein the melting temperature of the feedstock is 720-770 ℃.

5. The method of claim 3, wherein the weight of the nucleating agent relative to the weight of the feedstock is 3 kg/ton.

6. The method of claim 3, wherein the casting speed of the raw material is 125-135mm/min, and the cooling water flow rate is 6500-7200L/min.

7. The method of claim 3, further comprising the step of, prior to casting the feedstock, forming a 4XXX series aluminum alloy by: preheating equipment used in the casting process, and baking the launder, the degassing tank, the filter box and the die plate.

8. The method of claim 3, wherein the bar is homogenized at a heating temperature of 470-490 ℃ and a holding time of 3.5 h.

9. The method of claim 3, wherein the bar is cooled by air cooling.

10. The method of claim 3, further comprising the step of, prior to extruding the billet, forming the 4XXX series aluminum alloy as in claim 3: and placing the bar stock in an extruder heating furnace for preheating.

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