Preparation method of ultra-thick 5083 aluminum alloy plate

Abstract

The invention discloses a preparation method of an ultra-thick 5083 aluminum alloy plate, and belongs to the field of aluminum alloy processing. In order to solve the problems that when an ultra-thick 5083 plate is prepared through a traditional technology, layering and tearing are prone to occurring during cold rolling, and performance unbalance is caused due to the low total machining rate, the method comprises the steps of smelting casting, saw milling, heating, hot rolling, annealing and cold rolling coiling, annealing is conducted at the temperature of 250-300 DEG C for 6-12 h after hot rolling and before cold rolling, grain boundary Mg2Al3 phases are redissolved or spheroidized, and internal stress is eliminated. The final plate can meet the indexes of 285MPa < = Rm < = 385MPa, Rp0.2 > = 200MPa, A > = 10%, intergranular corrosion weight loss < = 15mg / cm and exfoliation corrosion PB and above.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum alloy processing and manufacturing, and particularly relates to a preparation method of an ultra-thick 5083 aluminum alloy plate. BACKGROUND

[0002] The 5083-H321 state plate has good mechanical properties and excellent corrosion performance, and is often used in marine environments. The thickness of the commonly used 5083-H321 state plate is 3-50 mm. For the ultra-thick 5083 plate with a thickness of more than 80 mm, the traditional production process is melting-casting-sawing-milling-hot rolling-cold rolling-annealing, and the following problems exist: in the cold rolling process, the plate thickness is too large, the rolling force required is large, and the rolling deformation at the center position of the thickness and the surface layer position is uneven, which will cause the plate to be torn from the center position of the thickness during the rolling process. In order to avoid plate tearing, the cold rolling single pass processing rate needs to be controlled, and the total processing rate is also reduced. However, the reduction of the total processing rate will lead to the imbalance of the plate strength and elongation, corrosion after cold rolling and annealing, and the performance indicators of the plate cannot meet the performance indicators of 285MPa≤Rm≤385MPa, Rp0.2≥200MPa, A≥10%, intergranular corrosion weight loss≤15mg / cm 2 , and peeling corrosion PB and above. SUMMARY

[0003] Therefore, the application discloses a preparation method of an ultra-thick 5083 aluminum alloy plate, which comprises the following steps:

[0004] S1. The 5083 aluminum alloy raw material is put into a melting furnace for melting, and then cast to obtain a 5083 aluminum alloy slab;

[0005] S2. The tail end and the gate end of the 5083 aluminum alloy slab are sawn, and the surface condensate shell layer is milled;

[0006] S3. The sawed and milled cast slab is heated in a push-type heating furnace, the heating temperature is 450-520 DEG C, and the heating time is 2-12 h;

[0007] S4. The heated 5083 aluminum alloy slab is hot-rolled to a target thickness, the final rolling temperature is 350-400 DEG C, and a 5083 aluminum alloy hot-rolled plate is obtained;

[0008] S5. The aluminum alloy hot-rolled plate is annealed at an annealing temperature of 250 DEG C-300 DEG C for 6-12 h. Through the setting of the annealing system, the corrosion performance of the product can be improved, and the internal stress of the plate can be eliminated, which is beneficial to avoiding the technical problem of cold rolling cracking of the plate in the subsequent rolling process.

[0009] S6. The 5083 aluminum alloy hot-rolled plate is cold-rolled and coiled to obtain a 5083 aluminum alloy cold-rolled plate.

[0010] The application can improve the corrosion performance of the product by adding an annealing process before cold rolling to dissolve or spheroidize the Mg2Al3 phase at the grain boundary of the product in advance, and can also eliminate the internal stress of the plate and further prevent the cold rolling cracking of the plate. After the large cold rolling processing rate of the traditional process, the stable annealing is processed, the work hardening is large, and the continuous distribution of the beta phase (Mg2Al3) at the grain boundary is released by the stable annealing in the temperature range of 200-250 DEG C, the plasticity is improved, the intergranular corrosion performance is improved, and the like, the precipitated phase is dissolved or spheroidized in advance, and the continuous distribution of the grain boundary is prevented to cause the intergranular corrosion to be poor.

[0011] As a supplement to the technical scheme of the application, in the step S1, the 5083 aluminum alloy raw material contains, by mass fraction, Si≤0.25%, Fe≤0.35%, Cu≤0.10%, 0.40%≤Mn≤1.0%, 4.2%≤Mg≤4.7%, 0.05%≤Cr≤0.20%, Zn≤0.20%, Ti≤0.10%, single impurity≤0.05%, total impurities≤0.15%, and the balance is Al.

[0012] As a supplement to the technical scheme of the application, in the step S1, the aluminum alloy smelting temperature is 730-770 DEG C, and after the smelting is completed, the aluminum alloy liquid is transferred to a holding furnace, argon-chlorine mixed gas is introduced into the holding furnace for refining, and the refining time is 0.5-2h. The casting temperature is 670-690 DEG C, the casting speed is 40-50mm / min, argon is introduced into the flow tank to remove hydrogen, and AlTi5B1 refiner is added to refine the ingot grain.

[0013] As a supplement to the technical scheme of the application, in the step S2, the ingot is sawed to 300-500mm at the ingot end, and sawed to 50-200mm at the gate end, then the flat ingot is milled to 10-25mm on the upper and lower surfaces, and milled to 5-10mm on the side surface.

[0014] As a supplement to the technical scheme of the application, in the step S4, the total hot rolling processing rate is 45%-85%.

[0015] As a supplement to the technical scheme of the application, in the step S4, the total hot rolling pass is 11-21 passes, and the reduction of each pass is 5-35mm.

[0016] As a supplement to the technical scheme of the application, in the step S6, the total cold rolling processing rate is 7-15%. For thick plates, in order to prevent the plate from tearing due to too large rolling processing rate, and at the same time meet the strength requirement of the finished product, the cold rolling processing rate is controlled to be 7%-15%. In the cold rolling process, the pass reduction needs to be strictly controlled, small reduction is easy to cause the plate to warp, and large reduction will cause the plate to fail to bite into the roll gap during rolling, and needs to be controlled between 0.5-2mm

[0017] As a supplement to the technical scheme of the present application, in step S6, the total cold rolling passes are 9-27 passes, and the reduction of each pass is 0.5-2 mm, and the cold rolling pass number is adjusted according to the cold rolling amount.

[0018] Beneficial effects: The preparation method of the ultra-thick 5083 aluminum alloy plate disclosed in the present application effectively reduces the impurities of raw materials and the hydrogen content of the ingot by precisely controlling the composition of the 5083 aluminum alloy raw material, matching the smelting at 730-770 DEG C, the chlorine-argon mixed gas refining, the casting at 670-690 DEG C, and the addition of AlTi5B1 refiner, and laying a foundation for excellent performance of the plate. The heating at 450-520 DEG C in the heating furnace and the final rolling temperature control at 350-400 DEG C in the hot rolling link, combined with the annealing process at 250-300 DEG C for 6-12 h before cold rolling, can make the grain boundary Mg2Al3 phase dissolve or spheroidize in advance, significantly eliminate the internal stress of the plate, avoid the problem of cold rolling delamination tearing in the traditional process from the root, and significantly improve the corrosion performance. In addition, the total cold rolling rate is controlled at 7%-15%, the pass reduction is set to 0.5-2 mm, and the total pass is 9-27 passes, which can not only avoid tearing caused by too large processing rate or warping and biting failure caused by too small processing rate, but also meet the strength requirement of the finished product, so that the ultra-thick plate finally reaches the mechanical indexes of 285 MPa≤Rm≤385 MPa, Rp0.2≥200 MPa, A≥10%, and the corrosion indexes of intergranular corrosion weight loss≤15 mg / cm2, and exfoliation corrosion PB and above, which is especially suitable for use in marine environment, and solves the problem that the traditional process is difficult to balance the processability and performance of the ultra-thick plate. DETAILED DESCRIPTION

[0019] The embodiments of the present application will be further described in detail below in combination with the examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0020] Example 1:

[0021] A 95mm thick 5083 aluminum alloy plate preparation method, characterized in that it comprises the following steps:

[0022] S1. Ingredients are prepared according to the following mass fraction: Si: 0.07%, Fe: 0.17%, Cu: 0.05%, Mn: 0.7%, Mg: 4.4%, Cr: 0.1%, Zn: 0.10%, Ti: 0.03%, single impurity ≤0.05%, total impurities ≤0.15%, and the balance is Al. The 5083 aluminum alloy raw material is put into a smelting furnace for smelting, the smelting temperature is 750℃, after smelting, the aluminum alloy liquid is transferred to a holding furnace, and chlorine-argon mixed gas is introduced into the holding furnace for refining, and the refining time is 1h. The casting temperature is 680℃, the casting speed is 45mm / min, argon is introduced into the runner to remove hydrogen, AlTi5B1 refiner is added to refine the ingot grain, and a 5083 aluminum alloy flat ingot is obtained;

[0023] S2. The starting end and the sprue end of the 5083 aluminum alloy flat ingot are sawn, and the surface crust layer is milled. Specifically, the starting end of the ingot is sawn 400mm, the sprue end is sawn 100mm, then the upper and lower surfaces of the flat ingot are milled 20mm, and the side surface is milled 8mm.

[0024] S3. The sawed and milled ingot is heated in a push-type heating furnace, the heating temperature is 500℃, and the heating time is 5h.

[0025] S4. The heated 5083 aluminum alloy flat ingot is hot-rolled, and the ingot is rolled from 600mm to 106mm through 21 passes. The thickness of the plate after each pass is 600mm, 585mm, 570mm, 549mm, 527mm, 501mm, 470mm, 441mm, 411mm, 382mm, 355mm, 327mm, 299mm, 268mm, 237mm, 208mm, 180mm, 155mm, 140mm, 127mm, 115mm, 106mm, and the final pass is completed at a finish rolling temperature of 360℃, and a 5083 aluminum alloy hot-rolled plate is obtained.

[0026] S5. The aluminum alloy hot-rolled plate is annealed at an annealing temperature of 270℃ for 8h.

[0027] S6. The 5083 aluminum alloy hot-rolled plate is cold-rolled and coiled to obtain a 5083 aluminum alloy cold-rolled plate. The hot-rolled plate with a thickness of 106mm is cold-rolled to a target thickness of 95mm. The entire cold-rolling process consists of 11 passes, and the thickness of the plate after each pass is 106mm (initial thickness), 105.5mm, 104.8mm, 103.8mm, 102.5mm, 101mm, 99.5mm, 98.3mm, 97.3mm, 96.5mm, 95.5mm, 95mm (finished thickness), and the cold-rolling reduction rate is 10.38%.

[0028] S7. Cut to size according to the size of the finished product.

[0029] Example 2:

[0030] A method for preparing a 155mm-thick 5083 aluminum alloy plate, characterized by comprising the following steps:

[0031] S1. Ingredients are prepared according to the following mass fractions: Si: 0.08%, Fe: 0.17%, Cu: 0.04%, Mn: 0.7%, Mg: 4.4%, Cr: 0.1%, Zn: 0.10%, Ti: 0.03%, individual impurities ≤0.05%, total impurities ≤0.15%, and the balance being Al. The 5083 aluminum alloy raw material is put into a smelting furnace for smelting, the smelting temperature is 750℃, after smelting is completed, the aluminum alloy liquid is transferred to a holding furnace, and chlorine-argon mixed gas is introduced into the holding furnace for refining, the refining time is 1h. The casting temperature is 680℃, the casting speed is 45mm / min, argon is introduced into the runner to remove hydrogen, AlTi5B1 refiner is added to refine the ingot grain, and a 5083 aluminum alloy slab is obtained;

[0032] S2. The starting end and the sprue end of the 5083 aluminum alloy slab are sawn, and the surface crust layer is milled, specifically, the starting end of the ingot is sawn by 400mm, the sprue end is sawn by 100mm, then the upper and lower surfaces of the slab are milled by 20mm, and the side surface is milled by 8mm.

[0033] S3. The sawed and milled ingot is heated in a push-type heating furnace, the heating temperature is 500℃, and the heating time is 5h;

[0034] S4. The heated 5083 aluminum alloy slab is hot-rolled, and the ingot is rolled from 600mm to 180mm through 17 passes, and the thickness of the slab after each pass is 600mm, 585mm, 570mm, 549mm, 527mm, 501mm, 470mm, 441mm, 411mm, 382mm, 355mm, 327mm, 299mm, 270mm, 242mm, 215mm, 190mm, 180mm, and the final pass is completed at a finish rolling temperature of 380℃, and a 5083 aluminum alloy hot-rolled plate is obtained;

[0035] S5. The aluminum alloy hot-rolled plate is annealed at an annealing temperature of 270℃ for 10h.

[0036] S6. The hot-rolled 5083 aluminum alloy plate is cold-rolled and coiled to obtain a 5083 aluminum alloy cold-rolled plate. The cold-rolling process is to cold-roll the hot-rolled plate with a thickness of 180 mm to a target thickness of 155 mm. The entire cold-rolling process has 19 passes, and the plate thickness after each pass is 180 mm (initial thickness), 179.5 mm, 178.8 mm, 177.8 mm, 176.3 mm, 174.9 mm, 173.1 mm, 171.5 mm, 169.8 mm, 168.2 mm, 166.5 mm, 165 mm, 163.7 mm, 162 mm, 160.5 mm, 159 mm, 157.5 mm, 156.5 mm, 155.5 mm, and 155 mm (finished product thickness), with a cold-rolling rate of 13.89%.

[0037] S7. The finished product is sawn to size.

[0038] Example 3:

[0039] A method for preparing a 290 mm thick 5083 aluminum alloy plate, characterized in that it comprises the following steps:

[0040] S1. The ingredients are prepared according to the following mass fractions: Si: 0.06%, Fe: 0.15%, Cu: 0.05%, Mn: 0.7%, Mg: 4.4%, Cr: 0.1%, Zn: 0.10%, Ti: 0.03%, individual impurities ≤0.05%, total impurities ≤0.15%, and the balance is Al. The 5083 aluminum alloy raw material is put into a melting furnace for melting, the melting temperature is 750℃, and after melting is completed, the aluminum alloy liquid is transferred to a holding furnace, argon-chlorine mixed gas is introduced into the holding furnace for refining, and the refining time is 1h. The casting temperature is 680℃, the casting speed is 45mm / min, argon is introduced into the runner to remove hydrogen, AlTi5B1 refiner is added to refine the ingot grains, and a 5083 aluminum alloy slab is obtained.

[0041] S2. The ingot end and the sprue end of the 5083 aluminum alloy slab are sawn, and the surface crust layer is milled. Specifically, the ingot end is sawn to 400mm, the sprue end is sawn to 100mm, then the upper and lower surfaces of the slab are milled to 20mm, and the side surface is milled to 8mm.

[0042] S3. The sawed and milled ingot is heated in a push-type heating furnace, the heating temperature is 500℃, and the heating time is 5h.

[0043] S4. The heated 5083 aluminum alloy slab is hot-rolled, and the cast slab is rolled from 600 mm to 330 mm through 13 passes, and the thickness of the slab after each pass is 600 mm, 585 mm, 570 mm, 549 mm, 527 mm, 501 mm, 470 mm, 441 mm, 412 mm, 389 mm, 368 mm, 348 mm, 335 mm, 330 mm, and the final pass is completed at a finish rolling temperature of 400 DEG C, and a 5083 aluminum alloy hot-rolled plate is obtained;

[0044] S5. The aluminum alloy hot-rolled plate is annealed at a temperature of 300 DEG C for 10 h.

[0045] S6. The 5083 aluminum alloy hot-rolled plate is cold-rolled and coiled to obtain a 5083 aluminum alloy cold-rolled plate. The cold-rolling process is to cold-roll the hot-rolled plate with a thickness of 330 mm to a target thickness of 95 mm, and the entire cold-rolling process is divided into 25 passes, and the thickness of the plate after each pass is 330 mm (initial thickness), 329.5 mm, 328.7 mm, 327.0 mm, 325.0 mm, 323.0 mm, 321.0 mm, 319.0 mm, 317.0 mm, 315.0 mm, 313.0 mm, 311.0 mm, 309.0 mm, 307.0 mm, 305.0 mm, 303.0 mm, 301.0 mm, 299.0 mm, 297.0 mm, 296.2 mm, 294.7 mm, 293.4 mm, 292.3 mm, 291.4 mm, 290.6 mm, 290 mm (finished thickness), and the cold-rolling rate is 12.1%.

[0046] S7. The finished size is sawn.

[0047] The mechanical properties of the plate obtained by rolling in the above embodiment are detected, and the results are shown in the following table:

[0048] Table 1. Mechanical properties and corrosion resistance detection table of the plate

[0049]

[0050] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can make equivalent replacement or change according to the technical scheme and inventive concept of the present application within the disclosed technical scope, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing ultra-thick 5083 aluminum alloy sheet, characterized in that, Includes the following steps: S1. 5083 aluminum alloy raw material is put into a melting furnace for melting, and then cast to obtain 5083 aluminum alloy flat ingot; S2. Sawing the ingot end and gate end of the 5083 aluminum alloy flat ingot and milling the solidified shell layer on its surface. S3. The milled ingot is heated in a pusher furnace at a temperature of 450-520℃ for 2-12 hours. S4. Hot-roll the heated 5083 aluminum alloy flat ingot to the target thickness, with a final rolling temperature of 350-400℃, to obtain a 5083 aluminum alloy hot-rolled plate. S5. Anneal the hot-rolled aluminum alloy sheet at a temperature of 250℃~300℃ for 6~12 hours. By setting the annealing process, the corrosion resistance of the product can be improved while eliminating internal stress in the sheet, which helps to avoid the technical problem of cold rolling cracking during subsequent rolling. S6. The 5083 aluminum alloy hot-rolled sheet is cold-rolled and coiled to obtain the 5083 aluminum alloy cold-rolled sheet.

2. The method for preparing ultra-thick 5083 aluminum alloy sheet according to claim 1, characterized in that, In step S1, the 5083 aluminum alloy raw material is as follows by mass fraction: Si≤0.25%, Fe≤0.35%, Cu≤0.10%, 0.40%≤Mn≤1.0%, 4.2%≤Mg≤4.7%, 0.05%≤Cr≤0.20%, Zn≤0.20%, Ti≤0.10%, single impurity ≤0.05%, total impurities ≤0.15%, and the balance is Al.

3. The method for preparing ultra-thick 5083 aluminum alloy sheet according to claim 1, characterized in that, In step S1, the aluminum alloy melting temperature is 730℃~770℃. After melting, the molten aluminum alloy is transferred to a holding furnace, where a chlorine-argon mixed gas is introduced for refining for 0.5-2 hours. The casting temperature is 670℃~690℃, the casting speed is 40~50mm / min, and argon gas is introduced into the casting channel to remove hydrogen. AlTi5B1 refining agent is added to refine the ingot grains.

4. The method for preparing ultra-thick 5083 aluminum alloy sheet according to claim 1, characterized in that, In step S2, the ingot drawing end is sawn off by 300-500mm, the gate end is sawn off by 50-200mm, and then the upper and lower surfaces of the flat ingot are milled by 10-25mm, and the side surface is milled by 5-10mm.

5. The method for preparing an ultra-thick 5083 aluminum alloy sheet according to claim 1, characterized in that, In step S4, the total hot rolling processing rate is 45%-85%.

6. The method for preparing an ultra-thick 5083 aluminum alloy sheet according to claim 1, characterized in that, In step S4, the total number of hot rolling passes is 11 to 21, and the reduction amount for each pass is 5 to 35 mm.

7. The method for preparing an ultra-thick 5083 aluminum alloy sheet according to claim 1, characterized in that, In step S6, the total cold rolling processing rate is 7-15%.

8. The method for preparing ultra-thick 5083 aluminum alloy sheet according to claim 1, characterized in that, In step S6, the total number of cold rolling passes is 9 to 27, and the processing rate of each pass is 0.5 to 2 mm.

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