A 6-series aluminum alloy plate homogenization process method and its application in aluminum alloy plate production

Abstract

The invention provides a 6-series aluminum alloy plate homogenization process method and application of the process method in aluminum alloy plate production. The process of the homogenization process method is as follows: the primary homogenization condition of the ingot is 565-580°C, and the temperature is kept for 4-12 hours; the secondary homogenization condition is 460-480°C, and the temperature is kept for 6-8 hours; the homogenization process method is used in the production of the aluminum alloy plate, the primary homogenization mainly aims to eliminate the uneven phenomenon of organization and chemical composition, and can make the iron-rich phase transformation complete and dispersed phase nucleation; the secondary homogenization mainly focuses on the coarsening of the dispersed phase, so that the dispersed phase grows to 1-3μm and is evenly distributed in the matrix, thereby improving the flanging performance of the 6-series aluminum alloy.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy automobile sheet processing, and in particular to a 6-series aluminum alloy sheet homogenization process method and application of the process method in aluminum alloy sheet production. Background Art

[0002] With the gradual improvement of environmental protection and emission standards, new energy vehicles with the characteristics of environmental protection and low energy consumption have become the key development direction of the automotive industry. Among them, automobile lightweighting is of great significance to the energy conservation and emission reduction of new energy vehicles. The application of lightweight body materials represented by aluminum alloy is precisely one of the effective ways to achieve energy conservation and emission reduction.

[0003] 6 series aluminum alloy has excellent properties in forming and baking hardening, and is widely used in transportation fields such as automobiles and ships. The semi-continuous casting method is used in the casting of 6 series aluminum alloy, which leads to the formation of non-equilibrium eutectic phase and dendrite segregation in 6 series aluminum alloy sheets, thus affecting the flanging performance of 6 series aluminum alloy sheets.

[0004] Homogenization treatment is an important means to improve dendrite segregation. In the application document with application number CN202210269892.X and subject name "A 6-series aluminum-magnesium-silicon alloy rod homogenization heat treatment process", a three-stage homogenization process is adopted, and the temperature is gradually raised to 563°C; among them, the first-stage homogenization is 347-353°C, and the holding time is 2.4-2.6h; the second-stage homogenization is 487-493°C, and the holding time is 2.9-3.1h; the third-stage homogenization is 557-563°C, and the holding time is 9.8-10.2h. The effect of improving strength and plasticity is achieved by improving dendrite segregation; but the three-stage homogenization is used, and the process and cooling method are cumbersome, which increases the difficulty of production; in the patent document with application number CN202110618380.5 and subject name A heat treatment method for inhibiting deformation recrystallization and coarse grains of Al-Mg-Si-Cu-Mn-Cr aluminum alloy, a two-stage homogenization is performed to make the ingot precipitate high-density, small-sized (micro-nano level) and uniformly distributed α-Al(MnCr)Si phase during heat treatment, which can inhibit the formation of coarse grains, thereby achieving the purpose of controlling the uniformity of grain size; but the method of using dispersed phase to inhibit the formation of coarse grains only considers the corrosion resistance and fatigue resistance of automotive structural parts, and does not involve the forming performance.

[0005] It can be seen that homogenization treatment is an important process to improve the plasticity of 6 series aluminum alloy. However, due to the shortcomings of cumbersome processing process and long processing time, the production process is difficult to control and has high cost in actual production. Therefore, providing a process method with fewer steps and good product flanging performance is of great significance to the application of 6 series aluminum alloy in automotive sheets. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a 6-series aluminum alloy plate homogenization process method and the application of the process method in the production of aluminum alloy plates. In the homogenization process method, a two-stage homogenization method of first high temperature and then cooling is adopted; when the homogenization process method is used in the production of aluminum alloy plates, the iron-rich phase transformation can be complete, and at the same time, the dispersed phase nucleation can be made to grow to 1-3μm and be evenly distributed in the matrix. Particles with larger sizes are more likely to produce the PSN effect, thereby improving the flanging performance of the 6-series aluminum alloy.

[0007] The technical solution of the present invention is as follows:

[0008] A 6 series aluminum alloy plate homogenization process method, the process is: the first-level homogenization condition of the ingot is 565-580 DEG C, and the heat preservation is 4-12 hours; the second-level homogenization condition is 460-480 DEG C, and the heat preservation is 6-8 hours; the homogenization process method is used in the production of aluminum alloy plates, the main purpose of the first-level homogenization is to eliminate the uneven phenomenon of organization and chemical composition, and the iron-rich phase can be completely transformed and the dispersed phase can be nucleated; if the iron-rich phase cannot be completely transformed, the β iron-rich phase has a sharp shape, which will have a splitting effect on the matrix during the flanging process, which is not conducive to the flanging; the second-level homogenization mainly focuses on the coarsening of the dispersed phase, so that the dispersed phase grows to 1-3μm and is evenly distributed in the matrix.

[0009] Preferably, the ingot comprises the following elements in weight percentage:

[0010] Si 0.95-1.15%, Mg 0.3-0.5%, Cu≤0.15%, Fe≤0.3%, Mn≤0.2%, Zn≤0.1%, Ti≤0.1%, and the balance is Al and unavoidable impurities.

[0011] The application of the above-mentioned 6 series aluminum alloy plate homogenization process method in the production of aluminum alloy plates includes ingot homogenization treatment, hot rolling, cooling, cold rolling, solution treatment and pre-aging.

[0012] Preferably, in the hot rolling, the ingot is directly hot rolled after being homogenized and taken out of the furnace, and the starting rolling temperature is 500-510°C.

[0013] Preferably, the cooling process is: uncoiling the hot rolled coil on an uncoiling machine and cooling it to 70±10°C.

[0014] Preferably, in the cold rolling, the hot rolled coil is cooled to 70±10° C. and then directly cold rolled.

[0015] Preferably, the solutionizing temperature is 540°C-580°C and the holding time is 20s-40s.

[0016] Preferably, the pre-aging temperature is 70°C-85°C.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. In the present invention, the primary homogenization is carried out at a high temperature and the secondary homogenization temperature is carried out at a temperature 85°C-120°C lower than the primary homogenization, which can achieve a complete transformation of the iron-rich phase, and at the same time, the dispersed phase can be nucleated and grown to 1-3μm and evenly distributed in the matrix. Particles with larger sizes are more likely to produce the PSN effect, thereby improving the flanging performance of the 6 series aluminum alloy.

[0019] 2. The homogenization process of the present invention is applied to the production of 6 series aluminum alloys. Under the premise of ensuring the flanging performance of the product, the production process is reduced, the production time is shortened, and the production cost is effectively saved.

[0020] 3. When the homogenization process method of the present invention is applied to the production of 6 series aluminum alloys, the proportion of the dispersed phase after double-stage homogenization in the matrix reaches more than 90%, and is evenly distributed; among the 1-3μm dispersed phase, the dispersed phase of about 1μm and the dispersed phase of about 2-3μm are staggered, among which the dispersed phase of 2-3μm accounts for more than about 65%, and the dispersed phase of about 1μm accounts for less than about 25%, which helps to improve the flanging performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a process flow chart of the 6 series aluminum alloy production process of the present invention.

[0023] Figure 2 This is the metallographic diagram of Example 1.

[0024] Figure 3 This is the metallographic dark field image of Example 1.

[0025] Figure 4 This is the flanging diagram corresponding to the flanging factor of Example 1.

[0026] Figure 5 This is the metallographic diagram of Example 2.

[0027] Figure 6 This is the metallographic dark field image of Example 2.

[0028] Figure 7 This is the flanging diagram corresponding to the flanging factor of Example 2.

[0029] Figure 8 This is the metallographic diagram of Example 3.

[0030] Fig. 9 This is the metallographic dark field image of Example 3.

[0031] Fig.10 This is the flanging diagram corresponding to the flanging factor of Example 3.

[0032] Fig.11 This is the metallographic diagram of Example 4.

[0033] Fig.12 This is the metallographic dark field image of Example 4.

[0034] Fig.13 This is the flanging diagram corresponding to the flanging factor of Example 4.

[0035] Fig.14 This is the metallographic diagram of Comparative Example 1.

[0036] Fig.15 This is the metallographic dark field image of Comparative Example 1.

[0037] Fig.16 This is the flanging diagram corresponding to the flanging factor of comparative example 1. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] Example 1

[0040] Combination Figure 1 This embodiment provides an application of a 6-series aluminum alloy plate homogenization process method in the production of aluminum alloy plates, and the process is as follows:

[0041] (1) Ingots containing the following elements in the following weight percentages:

[0042] Si 0.97%, Mg 0.36%, Cu 0.065%, Fe 0.18%, Mn 0.10%, Zn 0.004%, Ti 0.01%, the balance is Al and unavoidable impurities;

[0043] Casting is performed according to the above composition to obtain an ingot;

[0044] (2) Homogenization treatment:

[0045] The ingot was homogenized, the first homogenization condition was 565℃, and the temperature was kept for 4h; the second homogenization condition was 480℃, and the temperature was kept for 8h, and the cooling stage was air-cooled, and the cooling stage took 1h;

[0046] (3) Hot rolling:

[0047] After the ingot is homogenized, it is directly hot rolled out of the furnace, and the starting rolling temperature is 510℃;

[0048] (4) Uncoil cooling:

[0049] After hot rolling and coiling, the steel is uncoiled and cooled on the uncoiler to 70°C;

[0050] (5) Cold rolling

[0051] The hot rolled coil is cooled to 70±10℃ and then directly cold rolled;

[0052] (6) Solid solution

[0053] After cold rolling, solution treatment is carried out, the solution temperature is 540℃, and the holding time is 20s;

[0054] (7) Pre-aging

[0055] The pre-aging temperature is 70°C to obtain the product;

[0056] The product obtained in Example 1 was tested and the results are shown in Figure 2-Figure 4 ; Combine Figure 2-Figure 4 It can be seen that the iron-rich phase transformation of Example 1 is incomplete, the dispersed phase is small in size and unevenly distributed, the center of the grain is petal-shaped, and its flanging factor is 0.85.

[0057] Example 2

[0058] Combination Figure 1 This embodiment provides an application of a 6-series aluminum alloy plate homogenization process method in the production of aluminum alloy plates, and the process is as follows:

[0059] (1) Ingots containing the following elements in the following weight percentages:

[0060] Si 0.98%, Mg 0.37%, Cu 0.07%, Fe 0.20%, Mn 0.12%, Zn 0.0045%, Ti0.01%, the balance is Al and unavoidable impurities;

[0061] Casting is performed according to the above composition to obtain an ingot;

[0062] (2) Homogenization treatment:

[0063] The ingot was homogenized, the first homogenization condition was 565℃, and the temperature was kept for 8h; the second homogenization condition was 470℃, and the temperature was kept for 7h. The cooling stage was cooled by water mist, and the cooling stage took 1h.

[0064] (3) Hot rolling:

[0065] After the ingot is homogenized, it is directly hot rolled out of the furnace, and the starting rolling temperature is 500℃;

[0066] (4) Uncoil cooling:

[0067] After hot rolling and coiling, the steel is uncoiled and cooled on the uncoiler to 70°C;

[0068] (5) Cold rolling

[0069] The hot rolled coil is cooled to 70±10℃ and then directly cold rolled;

[0070] (6) Solid solution

[0071] After cold rolling, solution treatment is carried out, the solution temperature is 550℃, and the holding time is 30s;

[0072] (7) Pre-aging

[0073] The pre-aging temperature is 75°C to obtain the product;

[0074] The product obtained in Example 2 was tested and the results are shown in Figure 5-Figure 7 ; Combine Figure 5-Figure 7 It can be seen that the transformation ratio of the iron-rich phase in Example 2 is increased, but it still has not reached complete transformation. The size of the dispersed phase is increased, and the center of some grains is petal-shaped, and its flanging factor is 0.75.

[0075] Example 3

[0076] Combination Figure 1 This embodiment provides an application of a 6-series aluminum alloy plate homogenization process method in the production of aluminum alloy plates, and the process is as follows:

[0077] (1) Ingots containing the following elements in the following weight percentages:

[0078] Si 1.01%, Mg 0.40%, Cu 0.075%, Fe 0.21%, Mn 0.13%, Zn 0.005%, Ti0.01%, the balance is Al and unavoidable impurities;

[0079] Casting is performed according to the above composition to obtain an ingot;

[0080] (2) Homogenization treatment:

[0081] The ingot was homogenized, the first-level homogenization condition was 565℃, and the temperature was kept for 12h; the second-level homogenization condition was 460℃, and the temperature was kept for 6h. The cooling stage was cooled by water mist, and the cooling stage took 1h.

[0082] (3) Hot rolling:

[0083] After the ingot is homogenized, it is directly hot rolled out of the furnace, and the starting rolling temperature is 510℃;

[0084] (4) Uncoil cooling:

[0085] After hot rolling and coiling, the steel is uncoiled and cooled on the uncoiler to 70°C;

[0086] (5) Cold rolling

[0087] The hot rolled coil is cooled to 70±10℃ and then directly cold rolled;

[0088] (6) Solid solution

[0089] After cold rolling, solution treatment is carried out, the solution temperature is 560℃, and the holding time is 30s;

[0090] (7) Pre-aging

[0091] The pre-aging temperature is 80°C to obtain the product;

[0092] The product obtained in Example 3 was tested and the results are shown in Figure 8-Figure 10 ; Combine Figure 8-Figure 10 It can be seen that the iron-rich phase transformation of Example 3 is basically complete, and the dispersed phase size is coarsened, but it also has a dispersed phase of about 1 μm, and the dispersed phase is distributed relatively evenly, without the petal-shaped center of the grain, and its flanging factor is 0.5.

[0093] Example 4

[0094] Combination Figure 1 This embodiment provides an application of a 6-series aluminum alloy plate homogenization process method in the production of aluminum alloy plates, and the process is as follows:

[0095] (1) Ingots containing the following elements in the following weight percentages:

[0096] Si 1.00%, Mg 0.39%, Cu 0.068%, Fe 0.19%, Mn 0.11%, Zn 0.0048%, Ti0.01%, the balance is Al and unavoidable impurities;

[0097] Casting is performed according to the above composition to obtain an ingot;

[0098] (2) Homogenization treatment:

[0099] The ingot was homogenized at 560°C for 21 hours;

[0100] (3) Hot rolling:

[0101] After the ingot is homogenized, it is directly hot rolled out of the furnace, and the starting rolling temperature is 510℃;

[0102] (4) Uncoil cooling:

[0103] After hot rolling and coiling, the steel is uncoiled and cooled on the uncoiler to 70°C;

[0104] (5) Cold rolling

[0105] The hot rolled coil is cooled to 70±10℃ and then directly cold rolled;

[0106] (6) Solid solution

[0107] After cold rolling, solution treatment is carried out, the solution temperature is 560℃, and the holding time is 40s;

[0108] (7) Pre-aging

[0109] The pre-aging temperature is 85°C to obtain the product;

[0110] The product obtained in Example 4 was tested and the results are shown in Figure 11-13 ; Combine Figure 11-13 It can be seen that the iron-rich phase transformation of Example 4 is basically complete, the dispersed phase size is coarsened, and the distribution is uneven. It is basically enriched around the grain boundary, and the center of the grain is in the shape of a grain. Its flanging factor is 0.65.

[0111] Comparative Example 1

[0112] This comparative example provides an application of a 6-series aluminum alloy plate homogenization process method in the production of aluminum alloy plates, and the process is as follows:

[0113] (1) Ingots containing the following elements in the following weight percentages:

[0114] Si 0.60%, Mg 0.67%, Cu 0.12%, Fe 0.20%, Mn 0.12%, Zn 0.006%, Ti0.025%, the balance is Al and unavoidable impurities;

[0115] Casting is performed according to the above composition to obtain an ingot;

[0116] (2) Homogenization treatment:

[0117] The ingot was homogenized, the first-level homogenization condition was 580℃, and the temperature was kept for 12h; the second-level homogenization condition was 480℃, and the temperature was kept for 6h. The cooling stage was cooled by water mist, and the cooling stage took 1h.

[0118] (3) Hot rolling:

[0119] After the ingot is homogenized, it is directly hot rolled out of the furnace, and the starting rolling temperature is 500℃;

[0120] (4) Uncoil cooling:

[0121] After hot rolling and coiling, the steel is uncoiled and cooled on the uncoiler to 70°C;

[0122] (5) Cold rolling

[0123] The hot rolled coil is cooled to 70±10℃ and then directly cold rolled;

[0124] (6) Solid solution

[0125] After cold rolling, solution treatment is carried out, the solution temperature is 580℃, and the holding time is 40s;

[0126] (7) Pre-aging

[0127] The pre-aging temperature is 85°C to obtain the product;

[0128] The product obtained in Comparative Example 1 was tested and the results are shown in Figure 14-16 ; Combine Figure 14-16 It can be seen that the iron-rich phase transformation of Comparative Example 1 is basically complete, overburning occurs, the dispersed phase size is coarsened, and the coarsening degree of single-stage homogenization is not reached. In addition, the dispersed phase is unevenly distributed, and the centers of some grains are in the shape of grains and petals, and its flanging factor is 1.0.

[0129] The two-stage homogenization (high temperature first and then cooling) adopted in the present application has the advantages of reducing the process and simple cooling method compared to the two-stage homogenization of low temperature first and then high temperature in the prior art, saving production costs; among them, the first-stage high-temperature homogenization is conducive to the transformation of β to α iron-rich phase, and the transformation process is from network to chain, accompanied by the nucleation of dispersed phase; the second-stage cooling section homogenization adopts air cooling / water mist cooling (selected according to the temperature of the cooling section, the final cooling section takes 1h), and its main purpose is to make the dispersed phase grow. When it coarsens to a certain size (1-3μm), it can stimulate the PSN effect, randomize its texture, and improve the flanging performance.

[0130] Although the present invention has been described in detail by reference to the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A homogenization process for 6 series aluminum alloy plates, characterized in that: The process is: (1) Ingots containing the following elements in the following percentages by weight: Si 1.01%, Mg 0.40%, Cu 0.075%, Fe 0.21%, Mn 0.13%, Zn 0.005%, Ti 0.01%, the balance is Al and unavoidable impurities; Casting is performed according to the above composition to obtain an ingot; (2) Homogenization treatment: The ingot was homogenized, the first-level homogenization condition was 565℃, and the temperature was kept for 12h; the second-level homogenization condition was 460℃, and the temperature was kept for 6h. The cooling stage was cooled by water mist, and the cooling stage took 1h. (3) Hot rolling: After the ingot is homogenized, it is directly hot rolled out of the furnace, and the starting rolling temperature is 510℃; (4) Uncoil cooling: After hot rolling and coiling, the steel is uncoiled and cooled on the uncoiler to 70°C; (5) Cold rolling The hot rolled coil is cooled to 70±10℃ and then directly cold rolled; (6) Solid solution After cold rolling, solution treatment is carried out, the solution temperature is 560℃, and the holding time is 30s; (7) Pre-aging The pre-aging temperature is 80°C to obtain the product.

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