Large-thickness bent aluminum profile and preparation method and application thereof

Abstract

The invention discloses a large-thickness bent aluminum profile and its preparation method and application, and relates to the technical field of aluminum alloys. Specifically, the preparation method comprises: preparing raw materials according to a formula; the formula is as follows: Si 0.4%-0.8%, Mg 0.8%-1.2%, Fe 0.15%-0.55%, Cu 0.01%-1.0%, Mn 0.2%-0.9%, Ti0.02%-0.1%, Cr 0.1%-0.5%, and the rest is Al and unavoidable impurities, and the impurity content is ≤0.15%; then, the finished product is obtained after smelting, casting, homogenization, extrusion, bending, and aging. Among them, the minimum thickness of the thick plate profile blank obtained by extrusion is ≥20mm, and its bending angle is ≥120°. By implementing the present invention, a large-thickness bent aluminum profile with no obvious defects and high strength can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to a thick bent aluminum profile and a preparation method and application thereof. Background Art

[0002] Deformed aluminum alloys have high specific strength, high toughness, good processing performance and excellent corrosion resistance, and are widely used in aerospace, rail transportation, automobiles, and civil construction. Among them, Al-Mg-Si alloys are widely used due to their low raw material cost, good forming performance, and surface treatment. Aluminum profiles are usually straight and regular in shape, but for some special applications, bent aluminum profiles are required. However, existing aluminum profiles will crack when bent, becoming waste, and it is difficult to meet process requirements. In particular, some thicker profiles are more prone to defects such as breakage when bent. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a thick bent aluminum profile and a preparation method thereof, wherein the aluminum profile has good mechanical properties and has no obvious defects.

[0004] Another technical problem to be solved by the present invention is to provide a thick bent aluminum profile for use in bridge connectors.

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a thick bent aluminum profile, which comprises the following steps:

[0006] (1) Prepare raw materials in proportion; wherein the raw material formula in weight percentage is as follows:

[0007] Si 0.4%~0.8%, Mg 0.8%~1.2%, Fe 0.15%~0.55%, Cu 0.01%~1.0%, Mn 0.2%~0.9%, Ti 0.02%~0.1%, Cr 0.1%~0.5%, the rest is Al and unavoidable impurities, the impurity content is ≤0.15%;

[0008] (2) melting and casting the raw materials to obtain cast rods;

[0009] (3) homogenizing the cast rod;

[0010] (4) Extruding the homogenized cast rod to obtain a thick plate profile blank; wherein the minimum thickness of the thick plate profile blank is ≥10 mm;

[0011] (5) bending the thick plate profile blank at a preset temperature to obtain a bent profile blank; wherein the bending angle is ≥90° and the preset temperature is 150°C to 210°C;

[0012] (6) The bent profile blank is subjected to aging treatment to obtain a thick bent aluminum profile product.

[0013] As an improvement of the above technical solution, the sum of the weight ratio of Mn and Cr is ≥ 0.4%, and / or

[0014] The sum of the weight ratios of Fe and Ti is ≤0.5%.

[0015] As an improvement of the above technical solution, the sum of the weight ratio of Mn and Cr is 0.45% to 0.85%, and / or

[0016] The sum of the weight ratios of Fe and Ti is 0.35% to 0.45%.

[0017] As an improvement of the above technical solution, the weight ratio of Mg to Si is 1.4 to 1.6.

[0018] As an improvement of the above technical solution, in step (5), the preset temperature is 180°C to 200°C, and the bending processing time is 20s to 40s.

[0019] As an improvement of the above technical solution, the minimum thickness of the thick plate profile blank is 25 mm to 100 mm.

[0020] As an improvement of the above technical solution, in step (3), the homogenization treatment is a two-stage homogenization treatment; wherein the temperature of the first-stage homogenization treatment is 460°C to 480°C, and the treatment time is 1.5h to 5h; the temperature of the second-stage homogenization treatment is 540°C to 560°C, and the treatment time is 8h to 16h; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0021] As an improvement of the above technical solution, in step (6), the aging treatment is a two-stage aging treatment, wherein the first-stage aging treatment temperature is 160°C to 180°C, and the treatment time is 3h to 8h; the second-stage aging treatment temperature is 200°C to 210°C, and the treatment time is 0.5 to 2h.

[0022] Correspondingly, the present invention also discloses a thick bent aluminum profile, which is prepared by the above-mentioned method for preparing the thick bent aluminum profile.

[0023] Correspondingly, the present invention also discloses the application of the above-mentioned thick bent aluminum profile in bridge connectors.

[0024] The implementation of the present invention has the following beneficial effects:

[0025] The thick bent aluminum profile of the present invention effectively improves the toughness and machining performance of the aluminum alloy by regulating the strengthening elements in the formula, so that the present invention can bend the thick aluminum profile blank without defects such as breakage and cracks occurring during bending. In addition, the present invention performs bending and aging treatments in sequence after extrusion, which not only reduces the defects occurring during bending, but also improves the overall strength of the aluminum profile. Specifically, the tensile strength of the thick bent aluminum profile in the present application is ≥360MPa, and the yield strength is ≥320MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a physical picture of the thick bent aluminum profile in Example 2 of the present invention (bending part);

[0027] Figure 2 This is a physical picture of the aluminum alloy profile in Comparative Example 1 of the present invention;

[0028] Figure 3 This is a physical picture of the aluminum alloy profile in Comparative Example 2 of the present invention;

[0029] Figure 4 This is a physical picture of the aluminum alloy profile in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] The present invention discloses a method for preparing a thick bent aluminum profile, which specifically comprises the following steps:

[0032] (1) Prepare the raw materials in proportion;

[0033] The raw material formula in weight percentage is as follows:

[0034] Si 0.4%~0.8%, Mg 0.8%~1.2%, Fe 0.15%~0.55%, Cu 0.01%~1.0%, Mn 0.2%~0.9%, Ti 0.02%~0.1%, Cr 0.1%~0.5%, the rest is Al and unavoidable impurities, the impurity content is ≤0.15%;

[0035] Among them, Si and Mg can generate Mg2Si phase, which plays a strengthening role. Among them, the content of Si is 0.4wt% to 0.8wt%, and is exemplified by 0.5wt%, 0.55wt%, 0.6wt% or 0.7wt%, but not limited to this. The content of Mg is 0.8wt% to 1.2wt%, and is exemplified by 0.9wt%, 1wt%, 1.05wt% or 1.1wt%, but not limited to this. Preferably, in one embodiment of the present invention, Mg / Si (ratio by weight) is controlled to be 1.4 to 1.6. When Mg / Si>1.6, the solid solution of Mg2Si phase is difficult, and it is easy to become hard and brittle, destroying toughness. For plates with larger thickness (≥10mm), defects such as fracture and cracks are prone to occur when bending. When Mg / Si<1.4, the mechanical properties of the finished aluminum profile are poor.

[0036] Among them, Fe has a lubricating effect, which is beneficial to the later bending process; but too much Fe will greatly weaken the extrusion performance, making it difficult to extrude a thick plate profile blank with good performance. For this reason, the Fe content is controlled to be 0.15wt% to 0.55wt%, and 0.2wt%, 0.25wt%, 0.3wt% or 0.4wt% is exemplified, but not limited to this. Preferably, the Fe content is controlled to be 0.35wt% to 0.45wt%.

[0037] Among them, Ti also has a lubricating effect, which is not only beneficial to the later bending process, but also beneficial to the early extrusion process. Specifically, the content of Ti is 0.02-0.1wt%, and exemplarily 0.03wt%, 0.05wt%, 0.07wt% or 0.09wt%, but not limited thereto.

[0038] Preferably, in one embodiment of the present invention, the total content of Fe and Ti is controlled to be ≤0.5%. Based on this control, not only can high-speed extrusion (≥15m / min) of thicker profiles be met, but also no defects can be ensured during bending. More preferably, the total content of Fe and Ti is controlled to be 0.35wt% to 0.45wt%, exemplarily 0.38wt%, 0.4wt%, 0.41wt% or 0.43wt%, but not limited thereto.

[0039] Among them, Cu can be dissolved in the aluminum alloy matrix, and Al2Cu phase can be precipitated after aging to improve the mechanical properties of the aluminum alloy. However, more Cu will make the aluminum alloy hard and brittle, which is not suitable for bending. Therefore, the Cu content is controlled to be 0.01wt% to 0.1wt%. Exemplary is 0.02wt%, 0.03wt%, 0.05wt% or 0.08wt%, but not limited to this. Preferably, Cu is controlled to be 0.01wt% to 0.05wt%.

[0040] Among them, Mn and Cr can play a role in refining grains and improving mechanical properties. At the same time, it can increase the amount of fiber crystal structure of the bent aluminum profile, improve its longitudinal mechanical properties, and effectively reduce defects during bending. Specifically, the content of Mn is 0.2wt% to 0.9wt%, and is exemplified by 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt% or 0.8wt%, but is not limited to this. The content of Cr is 0.1wt% to 0.5wt%, and is exemplified by 0.15wt%, 0.2wt%, 0.3wt% or 0.4wt%, but is not limited to this. Preferably, in one embodiment of the present invention, the sum of the weight ratios of Mn and Cr is controlled to be ≥0.4wt%. Based on this control, the bending angle can be effectively increased and the defects generated during large-angle bending can be reduced. More preferably, the sum of the weight ratios of Mn and Cr is controlled to be 0.45wt% to 0.85wt%.

[0041] In addition, the aluminum alloy also contains some inevitable impurities, the content of which is ≤0.15wt%.

[0042] Specifically, raw materials are prepared according to the ratio of each element in the formula, and various raw materials can be pure metals of the elements or alloys. For example, cast iron can be used as the Fe raw material, and Al-20Fe alloy can be used as the Al raw material and the Fe raw material. For another example, pure copper can be used as the Cu raw material, and Al-50Cu alloy can be used as the Al raw material and the Cu raw material, but it is not limited thereto.

[0043] (2) melting and casting the raw materials to obtain cast rods;

[0044] The raw materials may be melted simultaneously, or melted in order of difficulty from difficult to easy, and then cast. Preferably, in one embodiment of the present invention, step (2) includes:

[0045] (2.1) melting the aluminum-containing raw material to obtain a first molten metal;

[0046] The aluminum-containing raw materials include aluminum ingots and recycled scraps, but are not limited thereto. The melting temperature is 720°C to 730°C.

[0047] (2.2) adding silicon-containing raw materials, copper-containing raw materials, manganese-containing raw materials, chromium-containing raw materials and iron-containing raw materials to the first molten metal in sequence, and skimming off the slag after melting to obtain a second molten metal;

[0048] The silicon-containing raw material may be a high-purity silicon ingot, but is not limited thereto. The copper-containing raw material may be a copper ingot or an Al-50Cu alloy, but is not limited thereto. The manganese-containing raw material may be an Al-20Mn alloy, but is not limited thereto. The chromium-containing raw material may be an Al-10Cr alloy, but is not limited thereto. The Fe-containing raw material may be cast iron or an Al-20Fe alloy, but is not limited thereto.

[0049] The smelting temperature is 720°C to 730°C. After melting, a slag remover is added to remove the slag.

[0050] (2.3) adding magnesium-containing raw materials to the second molten metal, and skimming off the slag after melting to obtain a third molten metal;

[0051] The magnesium-containing raw material is magnesium ingot, but not limited thereto. The melting temperature is 710° C. to 725° C. After melting, a slag remover is added to remove the slag.

[0052] (2.4) refining the third molten metal and allowing it to stand to obtain a fourth molten metal;

[0053] The refining temperature is 710°C to 720°C, the refining time is 10min to 40min, high-purity argon is introduced during the refining process, and the mixture is allowed to stand for 30min to 90min after the refining is completed.

[0054] (2.5) Cast the fourth molten metal to obtain a cast rod.

[0055] In the casting process, aluminum titanium boron wire is evenly added into the fourth molten metal, and the casting temperature is controlled to be 670-695°C.

[0056] (3) homogenizing the cast rod;

[0057] The temperature of the homogenization treatment is 450-580°C, and the treatment time is 5-24h. After the homogenization treatment, water mist and strong wind are used for cooling. Preferably, in one embodiment of the present invention, a two-stage homogenization treatment is adopted, wherein the temperature of the first-stage homogenization treatment is 460-480°C, and the treatment time is 1.5h-5h; the temperature of the second-stage homogenization treatment is 540-560°C, and the treatment time is 8h-16h; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0058] (4) Extruding the homogenized cast rod to obtain a thick plate profile blank;

[0059] The temperature of the cast rod at the extrusion inlet is 520°C to 540°C, the temperature of the thick plate profile blank at the extrusion outlet is 530°C to 550°C, and the extrusion speed is 12m / min to 20m / min.

[0060] Among them, the thick-plate aluminum profile blank obtained by extrusion is a blank with a uniform thickness or a blank with a non-uniform thickness. Its minimum thickness ≥ 10 mm. Preferably, it is 25 mm - 100 mm, and exemplary ones are 30 mm, 40 mm, 50 mm, 60 mm or 70 mm, but not limited thereto. It should be noted that when the thick-plate aluminum profile blank is a blank with a non-uniform thickness, the width of the non-uniform thickness part is relatively large, which is not a common thin-wall profile in the art. For example, the cross-section of the thick-plate aluminum profile blank is in a character 'pin' shape, and the width of the part with a larger thickness is also relatively large to facilitate subsequent bending treatment.

[0061] (5) Perform bending treatment on the thick-plate profile blank at a preset temperature to obtain a bent profile blank;

[0062] Among them, the temperature of the bending treatment is 150°C - 210°C. Specifically, the inventor unexpectedly found through production practice that when the bending treatment temperature is within this range, it not only does not affect the hardness and strength of the original thick-plate profile blank, but also can effectively improve the elongation rate of the bending area, doubling it or more, thereby effectively reducing the defects generated during bending. Exemplary, the temperature of the bending treatment is 160°C, 170°C, 180°C, 190°C or 200°C, but not limited thereto. The preferred bending treatment temperature is 180°C - 200°C. At this temperature, the defects during large bending angles can be effectively reduced.

[0063] Among them, the bending treatment time is 20 s - 60 s. Specifically, since heating is carried out during the bending treatment, if the bending treatment time > 60 s, the alloy hardens and defects such as cracking are likely to occur. If the bending treatment time < 20 s, the alloy has poor toughness and defects such as cracking are also likely to occur. Exemplary, the bending treatment time is 25 s, 30 s, 40 s, 45 s, 50 s or 55 s, but not limited thereto. Preferably, the bending treatment time is 20 s - 40 s.

[0064] Among them, the bending angle refers to the angle by which the bent section (the section that moves during bending) is bent. Through the coordination of the formula and process, the bending angle of the thick-plate profile blank of the present invention can reach more than 90° without obvious defects. Preferably, the bending angle is 120° - 180°. The present invention can achieve double folding without obvious defects.

[0065] (6) Perform aging treatment on the bent profile blank, and then the finished product of the large-thickness bent aluminum profile is obtained.

[0066] The aging treatment temperature is 160-220°C, and the aging treatment time is 1-15h, but not limited thereto. Preferably, in one embodiment of the present invention, the aging treatment is a two-stage aging treatment, wherein the first-stage aging treatment temperature is 160-180°C, and the treatment time is 3h-8h; the second-stage aging treatment temperature is 200-210°C, and the treatment time is 0.5-2h. Through the two-stage aging treatment, the bent profile blank can be effectively strengthened and given a higher mechanical strength.

[0067] Specifically, the thick bent aluminum profile obtained by the above formula and preparation method has a tensile strength of ≥360MPa, and can reach a maximum of about 450MPa; a yield strength of ≥320MPa, and can reach a maximum of about 400MPa; and an elongation of ≥15%, and can reach a maximum of about 20%.

[0068] Correspondingly, the present invention also discloses a thick bent aluminum profile, which is prepared by the above method and can be used in bridge connectors.

[0069] The present invention is described below with specific embodiments:

[0070] Example 1

[0071] This embodiment provides a thick curved aluminum profile, the formula of which is:

[0072] Si 0.58%, Mg 0.94%, Fe 0.53%, Cu 0.1%, Mn 0.25%, Ti 0.05%, Cr 0.15%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0073] Its preparation method is:

[0074] (1) Prepare the raw materials in proportion;

[0075] (2) melting the aluminum ingot and the recycled waste at 730° C. to obtain a first molten metal;

[0076] (3) adding silicon ingot, Al-50Cu alloy, Al-20Mn alloy, Al-10Cr alloy and Al-20Fe alloy to the first molten metal in sequence, adding a slag remover after melting at 725° C., and removing the slag to obtain a second molten metal;

[0077] (4) adding magnesium ingots to the second molten metal, adding a slag remover after melting at 720° C., and removing the slag to obtain a third molten metal;

[0078] (5) refining the third molten metal at 710° C. for 20 min, and then allowing to stand for 80 min to obtain a fourth molten metal;

[0079] (6) Casting the fourth molten metal to obtain a cast rod, wherein the casting temperature is 680°C.

[0080] (7) homogenizing the cast rod; wherein the homogenization temperature is 550° C. and the homogenization time is 18 h;

[0081] (8) Extruding the homogenized cast rod to obtain a thick plate profile blank;

[0082] The temperature of the cast rod at the extrusion inlet is 530°C, and the temperature of the thick plate profile blank at the extrusion outlet is 540°C. The extrusion speed is 12m / min. The thick plate profile blank is in the shape of a plate, and its thickness is 22mm.

[0083] (9) The thick plate profile blank is bent at 170°C for 30 seconds at a bending angle of 120°.

[0084] (10) The bent profile blank is subjected to aging treatment to obtain a thick bent aluminum profile product, wherein the aging treatment temperature is 200° C. and the treatment time is 12 h.

[0085] Example 2

[0086] This embodiment provides a thick curved aluminum profile, the formula of which is:

[0087] Si 0.65%, Mg 0.95%, Fe 0.42%, Cu 0.1%, Mn 0.25%, Ti 0.05%, Cr 0.17%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0088] Its preparation method is:

[0089] (1) Prepare the raw materials in proportion;

[0090] (2) melting the aluminum ingot and the recycled waste at 730° C. to obtain a first molten metal;

[0091] (3) adding silicon ingot, Al-50Cu alloy, Al-20Mn alloy, Al-10Cr alloy and Al-20Fe alloy to the first molten metal in sequence, adding a slag remover after melting at 725° C., and removing the slag to obtain a second molten metal;

[0092] (4) adding magnesium ingots to the second molten metal, adding a slag remover after melting at 720° C., and removing the slag to obtain a third molten metal;

[0093] (5) refining the third molten metal at 710° C. for 20 min, and then allowing to stand for 80 min to obtain a fourth molten metal;

[0094] (6) Casting the fourth molten metal to obtain a cast rod, wherein the casting temperature is 680°C.

[0095] (7) subjecting the cast rod to a two-stage homogenization treatment; wherein the temperature of the first-stage homogenization treatment is 465° C., and the treatment time is 2.5 h; the temperature of the second-stage homogenization treatment is 550° C., and the treatment time is 10 h;

[0096] (8) Extruding the homogenized cast rod to obtain a thick plate profile blank;

[0097] The temperature of the cast rod at the extrusion inlet is 530°C, and the temperature of the thick plate profile blank at the extrusion outlet is 540°C. The extrusion speed is 13.5m / min. The thick plate profile blank is in the shape of a plate, and its thickness is 25mm.

[0098] (9) The thick plate profile blank is bent at 170°C for 30 seconds at a bending angle of 180°.

[0099] (10) The bent profile blank is subjected to a double-stage aging treatment to obtain a large-thickness bent aluminum profile finished product. The first-stage aging treatment temperature is 175°C and the treatment time is 5 hours; the second-stage aging treatment temperature is 200°C and the treatment time is 1 hour. The finished product is shown in the figure. Figure 1 shown.

[0100] Example 3

[0101] This embodiment provides a thick curved aluminum profile, the formula of which is:

[0102] Si 0.65%, Mg 0.95%, Fe 0.37%, Cu 0.03%, Mn 0.25%, Ti 0.05%, Cr 0.17%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0103] Its preparation method is:

[0104] (1) Prepare the raw materials in proportion;

[0105] (2) melting the aluminum ingot and the recycled waste at 730° C. to obtain a first molten metal;

[0106] (3) adding silicon ingot, Al-50Cu alloy, Al-20Mn alloy, Al-10Cr alloy and Al-20Fe alloy to the first molten metal in sequence, adding a slag remover after melting at 725° C., and removing the slag to obtain a second molten metal;

[0107] (4) adding magnesium ingots to the second molten metal, adding a slag remover after melting at 720° C., and removing the slag to obtain a third molten metal;

[0108] (5) refining the third molten metal at 710° C. for 20 min, and then allowing to stand for 80 min to obtain a fourth molten metal;

[0109] (6) Casting the fourth molten metal to obtain a cast rod, wherein the casting temperature is 680°C.

[0110] (7) subjecting the cast rod to a two-stage homogenization treatment; wherein the temperature of the first-stage homogenization treatment is 465° C., and the treatment time is 2.5 h; the temperature of the second-stage homogenization treatment is 550° C., and the treatment time is 10 h;

[0111] (8) Extruding the homogenized cast rod to obtain a thick plate profile blank;

[0112] The temperature of the cast rod at the extrusion inlet is 530°C, and the temperature of the thick plate profile blank at the extrusion outlet is 540°C. The extrusion speed is 17m / min. The thick plate profile blank is in the shape of a plate, and its thickness is 30mm.

[0113] (9) The thick plate profile blank is bent at 170°C for 30 seconds at a bending angle of 180°.

[0114] (10) The bent profile blank is subjected to a double-stage aging treatment to obtain a thick bent aluminum profile product, wherein the primary aging treatment temperature is 175° C. and the treatment time is 5 h; the secondary aging treatment temperature is 200° C. and the treatment time is 1 h.

[0115] Example 4

[0116] This embodiment provides a thick curved aluminum profile, the formula of which is:

[0117] Si 0.65%, Mg 0.95%, Fe 0.42%, Cu 0.03%, Mn 0.38%, Ti 0.05%, Cr 0.25%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0118] Its preparation method is:

[0119] (1) Prepare the raw materials in proportion;

[0120] (2) melting the aluminum ingot and the recycled waste at 730° C. to obtain a first molten metal;

[0121] (3) adding silicon ingot, Al-50Cu alloy, Al-20Mn alloy, Al-10Cr alloy and Al-20Fe alloy to the first molten metal in sequence, adding a slag remover after melting at 725° C., and removing the slag to obtain a second molten metal;

[0122] (4) adding magnesium ingots to the second molten metal, adding a slag remover after melting at 720° C., and removing the slag to obtain a third molten metal;

[0123] (5) refining the third molten metal at 710° C. for 20 min, and then allowing to stand for 80 min to obtain a fourth molten metal;

[0124] (6) Casting the fourth molten metal to obtain a cast rod, wherein the casting temperature is 680°C.

[0125] (7) subjecting the cast rod to a two-stage homogenization treatment; wherein the temperature of the first-stage homogenization treatment is 465° C., and the treatment time is 2.5 h; the temperature of the second-stage homogenization treatment is 550° C., and the treatment time is 10 h;

[0126] (8) Extruding the homogenized cast rod to obtain a thick plate profile blank;

[0127] The temperature of the cast rod at the extrusion inlet is 530°C, and the temperature of the thick plate profile blank at the extrusion outlet is 540°C. The extrusion speed is 15.2m / min. The thick plate profile blank is in the shape of a plate, and its thickness is 280mm.

[0128] (9) The thick plate profile blank is bent at 170°C for 30 seconds at a bending angle of 180°.

[0129] (10) The bent profile blank is subjected to a double-stage aging treatment to obtain a thick bent aluminum profile product, wherein the primary aging treatment temperature is 175° C. and the treatment time is 5 h; the secondary aging treatment temperature is 200° C. and the treatment time is 1 h.

[0130] Example 5

[0131] This embodiment provides a thick curved aluminum profile, the formula of which is:

[0132] Si 0.65%, Mg 0.95%, Fe 0.37%, Cu 0.03%, Mn 0.38%, Ti 0.05%, Cr 0.25%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0133] Its preparation method is:

[0134] (1) Prepare the raw materials in proportion;

[0135] (2) melting the aluminum ingot and the recycled waste at 730° C. to obtain a first molten metal;

[0136] (3) adding silicon ingot, Al-50Cu alloy, Al-20Mn alloy, Al-10Cr alloy and Al-20Fe alloy to the first molten metal in sequence, adding a slag remover after melting at 725° C., and removing the slag to obtain a second molten metal;

[0137] (4) adding magnesium ingots to the second molten metal, adding a slag remover after melting at 720° C., and removing the slag to obtain a third molten metal;

[0138] (5) refining the third molten metal at 710° C. for 20 min, and then allowing to stand for 80 min to obtain a fourth molten metal;

[0139] (6) Casting the fourth molten metal to obtain a cast rod, wherein the casting temperature is 680°C.

[0140] (7) subjecting the cast rod to a two-stage homogenization treatment; wherein the temperature of the first-stage homogenization treatment is 465° C., and the treatment time is 2.5 h; the temperature of the second-stage homogenization treatment is 550° C., and the treatment time is 10 h;

[0141] (8) Extruding the homogenized cast rod to obtain a thick plate profile blank;

[0142] The temperature of the cast rod at the extrusion inlet is 530°C, and the temperature of the thick plate profile blank at the extrusion outlet is 540°C. The extrusion speed is 19m / min. The thick plate profile blank is in the shape of a plate, and its thickness is 30mm.

[0143] (9) The thick plate profile blank is bent at 170°C for 30 seconds at a bending angle of 180°.

[0144] (10) The bent profile blank is subjected to a double-stage aging treatment to obtain a thick bent aluminum profile product, wherein the primary aging treatment temperature is 175° C. and the treatment time is 5 h; the secondary aging treatment temperature is 200° C. and the treatment time is 1 h.

[0145] Comparative Example 1

[0146] This comparative example provides an aluminum alloy profile, which is different from Example 1 in that a bending process is performed after aging, and the rest is the same as the example. The results show that when bending is performed after aging, the aluminum alloy profile is directly broken during the bending process.

[0147] Comparative Example 2

[0148] This comparative example provides an aluminum alloy profile, which differs from Example 1 in that in step (9), the bending process is performed at room temperature (30° C.) The results show that when the bending process is performed without heat treatment, cracks appear at the bending part, and even part of the part breaks.

[0149] Comparative Example 3

[0150] This comparative example provides an aluminum alloy profile, which differs from Example 1 in that in step (9), the bending process is performed at 250° C. The results show that when the profile is bent at this temperature, cracks appear on the outer side of the bend.

[0151] Since the aluminum alloy blanks of Comparative Examples 1 to 3 all have defects such as cracks and fractures, only the thick bent aluminum profiles of Examples 1 to 5 were tested, and the specific test results are as follows:

[0152] The aluminum alloys obtained in Examples 1 to 6 and Comparative Examples 1 to 2 were tested, and the specific results are shown in the following table:

[0153] Tensile strength / MPa Yield strength / MPa Elongation / % Example 1 365 330 15.3 Example 2 390 368 18.5 Example 3 435 396 19.5 Example 4 415 386 18 Example 5 455 403 20.5

[0154] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A method for preparing a thick bent aluminum profile, characterized in that: The following steps are involved: (1) Prepare raw materials in proportion; the raw material formula in weight percentage is as follows: Si 0.4%~0.8%, Mg 0.8%~1.2%, Fe 0.15%~0.55%, Cu 0.01%~1.0%, Mn 0.2%~0.9%, Ti0.02%~0.1%, Cr 0.1%~0.5%, the rest is Al and unavoidable impurities, the impurity content is ≤0.15%; the sum of the weight percentages of Mn and Cr is ≥0.4%, the sum of the weight percentages of Fe and Ti is ≤0.5%, and the weight ratio of Mg to Si is 1.4~1.6; (2) Melting and casting the raw materials to obtain cast bars; (3) homogenizing the cast rod; (4) Extruding the homogenized cast rod to obtain a thick plate profile blank; wherein the minimum thickness of the thick plate profile blank is ≥10 mm; (5) Bending the thick plate profile blank at a preset temperature to obtain a bent profile blank; wherein the bending angle is ≥90° and the preset temperature is 150°C to 210°C; (6) subjecting the bent profile blank to aging treatment to obtain a thick bent aluminum profile product; Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 160℃~180℃, and the treatment time is 3h~8h; the second-stage aging treatment temperature is 200℃~210℃, and the treatment time is 0.5~2h.

2. The method for preparing a thick bent aluminum profile according to claim 1, characterized in that: The sum of the weight percentages of Mn and Cr is 0.45% to 0.85%, and / or The sum of the weight percentages of Fe and Ti is 0.35% to 0.45%.

3. The method for preparing a thick bent aluminum profile according to claim 1, characterized in that: In step (5), the preset temperature is 180°C to 200°C, and the bending processing time is 20s to 40s.

4. The method for preparing a thick bent aluminum profile according to claim 1, characterized in that: The minimum thickness of the thick plate profile blank is 25 mm to 100 mm.

5. The method for preparing a thick bent aluminum profile according to claim 1, characterized in that: In step (3), the homogenization treatment is a two-stage homogenization treatment; wherein, the temperature of the first-stage homogenization treatment is 460°C~480°C, and the treatment time is 1.5h~5h; the temperature of the second-stage homogenization treatment is 540°C~560°C, and the treatment time is 8h~16h; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

6. A thick bent aluminum profile, characterized in that: The aluminum profile is prepared by the method for preparing a thick bent aluminum profile as described in any one of claims 1 to 5.

7. Use of the thick bent aluminum profile as claimed in claim 6 in bridge connectors.

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