5083 aluminum alloy plate for deep drawing and preparation method of 5083 aluminum alloy plate

Abstract

The invention discloses a 5083 aluminum alloy plate for deep drawing and a preparation method of the 5083 aluminum alloy plate. The 5083 aluminum alloy plate is prepared through the procedures of burdening, smelting, casting, sawing and milling, homogenizing treatment, hot rolling, primary cold rolling, intermediate annealing, secondary cold rolling, finished product annealing and slitting in sequence. The homogenization treatment adopts a three-stage heating process: in the first stage of soaking, the furnace gas temperature is 490-510 DEG C, the metal temperature is 440-460 DEG C, and heat preservation is performed for 4-8 hours; second-stage soaking is conducted, specifically, the furnace gas temperature is 550-570 DEG C, the metal temperature is 510-530 DEG C, and heat preservation is conducted for 12-16 h; and in the third stage of soaking, the furnace gas temperature is 480-500 DEG C, the metal temperature is 475-485 DEG C, and heat preservation is conducted for 2-4 h. The problems of quality defects of wrinkling and cracking in the punching process of the 5083 aluminum alloy plate are solved, and the product quality is improved.

Description

Technical Field

[0001] The invention relates to the field of aluminum alloy manufacturing, and in particular to a 5083 aluminum alloy plate for deep drawing and a preparation method thereof. Background Art

[0002] Aluminum alloys are widely used in transportation and daily necessities due to their excellent forming properties, oxidation resistance and high specific density. The common production process of existing aluminum alloy plates is: casting → sawing and milling → heating → hot rolling → cold rolling → cleaning → annealing → finished product slitting. The alloy plates produced by this process have low yield strength ratio in O state, and have quality defects such as stamping wrinkling (Lüders band), low elongation in H32 state, and stamping cracking. Summary of the invention

[0003] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a 5083 aluminum alloy plate for deep drawing and a preparation method thereof, so as to solve the problems of metal overburning and easy cracking in the prior art and improve product quality.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A method for preparing a 5083 aluminum alloy plate for deep drawing, which comprises the following steps: batching - melting - casting - sawing and milling - homogenization treatment - hot rolling - first cold rolling - intermediate annealing - second cold rolling - finished product annealing - slitting.

[0006] The homogenization treatment adopts a three-stage heating process:

[0007] The first stage of equalization: furnace gas temperature 490 ~ 510 ℃, metal temperature 440 ~ 460 ℃, keep warm for 4 ~ 8 hours;

[0008] The second stage of equalization: furnace gas temperature 550-570℃, metal temperature 510-530℃, keep warm for 12-16h;

[0009] The third stage of equalizing: furnace gas temperature 480 ~ 500 ℃, metal temperature 475 ~ 485 ℃, keep warm for 2 ~ 4h.

[0010] Furthermore, the ingredients are prepared according to the following alloy element mass percentages: Si 0-0.2%; Fe 0-0.3%; Cu 0-0.05%; Mn 0.5-0.8%; Mg 4.1-4.6%; Cr 0.05-0.15%; Zn 0.015-0.025%; Ti 0.01-0.02%; single impurity ≤0.05%; total impurities ≤0.15%; the balance is Al.

[0011] Furthermore, in the batching process, the aluminum raw material includes solid aluminum and liquid aluminum, and the aluminum raw material is prepared according to the following mass percentages: 40% to 60% solid aluminum and 40% to 60% liquid aluminum.

[0012] Furthermore, the smelting process specifically includes:

[0013] Melting: 5083 aluminum alloy raw materials are added into a melting furnace to melt into aluminum alloy melt, and the melt temperature is 740-760℃;

[0014] Sodium removal: adding a sodium removal agent to the above smelting furnace, the amount of the sodium removal agent added is 3-5‰ of the total amount of the aluminum alloy raw materials, and the sodium removal time is 35-45 minutes;

[0015] First refining: After sodium removal, add refining agent to the smelting furnace. The amount of refining agent added is 1.5-2.5‰ of the total amount of aluminum alloy raw materials. Keep the temperature at 740-760℃ and the refining time is 55-65min.

[0016] Second refining: the aluminum alloy melt after the first refining is sent to a holding furnace, kept at 730-750°C, and the refining time is 55-65 minutes.

[0017] Furthermore, the hot rolling start temperature is 450-500°C, and the final rolling temperature is 300-350°C.

[0018] Furthermore, the processing rate of the first cold rolling is ≥70%, and the thickness of the product obtained by the first cold rolling is 0.9-1.4 mm; the processing rate of the second cold rolling is 10-20%, and the thickness of the product obtained by the second cold rolling is 0.8-1.0 mm.

[0019] Furthermore, the intermediate annealing process adopts two-stage low-temperature rapid annealing:

[0020] The first stage of intermediate annealing: furnace gas temperature 230 ~ 250 ℃, metal temperature 140 ~ 160 ℃, keep warm for 3 ~ 6 hours;

[0021] The second stage intermediate annealing: furnace gas temperature 390 ~ 410 ℃, metal temperature 310 ~ 320 ℃, keep warm for 3 ~ 5h.

[0022] Furthermore, the finished product annealing process adopts two-stage high temperature slow annealing:

[0023] The first stage of finished product annealing: furnace gas temperature 330 ~ 350 ℃, metal temperature 230 ~ 250 ℃, heat preservation 4 ~ 6h;

[0024] The second stage of finished product annealing: furnace gas temperature 370 ~ 390 ℃, metal temperature 320 ~ 340 ℃, keep warm for 3 ~ 5h.

[0025] The present invention also provides a 5083 aluminum alloy sheet for deep drawing, and the 5083 aluminum alloy sheet for deep drawing is prepared by the preparation method as described above.

[0026] Furthermore, the tensile strength of the 5083 aluminum alloy sheet for deep drawing is 310-325Mp, the yield strength is 160-200Mp, the elongation is 18-24%, and the yield strength ratio is 0.57-0.65.

[0027] The beneficial effects of the present invention are as follows: a 5083 aluminum alloy plate for deep drawing is prepared by sequentially adopting the processes of batching-smelting-casting-sawing-homogenization-hot rolling-first cold rolling-intermediate annealing-second cold rolling-finished product annealing-slitting; a three-stage heating process is adopted in the homogenization process, which solves the problems of metal overburning, insufficient diffusion of segregated atoms, poor organizational uniformity, and easy cracking in the prior art, improves metal uniformity, prevents metal overburning, and improves the quality of the plate surface during rolling. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a metallographic image of the sample after intermediate annealing in Example 1 of the present invention;

[0029] Figure 2 is a metallographic image of the finished product after annealing of the finished product of Example 1 of the present invention;

[0030] Figure 3 is a force-displacement curve diagram of a tensile test of the finished product of Example 1 of the present invention;

[0031] Figure 4 is a cupping experiment diagram of Example 1 of the present invention;

[0032] Figure 5 is a force-displacement curve diagram of a tensile test of a finished product of Example 2 of the present invention;

[0033] Figure 6 It is a schematic diagram of a new energy vehicle battery pack cover plate formed by stamping the finished product of Example 2 of the present invention;

[0034] Figure 7 is a force-displacement curve diagram of a tensile test of a finished product of Example 3 of the present invention;

[0035] Figure 8 It is a schematic diagram of a finished product of Example 3 of the present invention being punched into a bag. DETAILED DESCRIPTION

[0036] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with embodiments.

[0037] The present invention provides a method for preparing a 5083 aluminum alloy plate for deep drawing, which is prepared by sequentially adopting the steps of batching-smelting-casting-sawing-homogenization-hot rolling-first cold rolling-intermediate annealing-second cold rolling-finished product annealing-slitting;

[0038] The homogenization treatment adopts a three-stage heating process:

[0039] The first stage of equalization: furnace gas temperature 490 ~ 510 ℃, metal temperature 440 ~ 460 ℃, keep warm for 4 ~ 8 hours;

[0040] The second stage of equalization: furnace gas temperature 550-570℃, metal temperature 510-530℃, keep warm for 12-16h;

[0041] The third stage of equalizing: furnace gas temperature 480 ~ 500 ℃, metal temperature 475 ~ 485 ℃, keep warm for 2 ~ 4h.

[0042] The invention prepares a 5083 aluminum alloy plate for deep drawing through the process of batching-melting-casting-sawing-homogenization-hot rolling-first cold rolling-intermediate annealing-second cold rolling-finished product annealing-slitting. The aluminum alloy ingot after casting and sawing is heated in three stages. The furnace gas temperature in the first stage is low and the heating speed is slow, which can effectively reduce the temperature difference of the ingot and prolong the soaking time, so that the segregated atoms can be fully diffused and the uniformity of the ingot is improved. The second stage of low-temperature soaking can ensure the full diffusion of the segregated atoms and prevent the ingot from being overburned due to excessive homogenization temperature, resulting in the problem of low plasticity and easy cracking of the material. In the third stage, the ingot is cooled to 480°C and kept warm before being taken out of the furnace for rolling. Rolling at this temperature can improve the aluminum sticking problem in the rolling process and improve the plate surface quality. The three-stage heating solves the problems of metal overburning, insufficient diffusion of segregated atoms, poor organizational uniformity and easy cracking in the prior art, and further reduces the possibility of cracking in the stamping process.

[0043] The preparation method of a 5083 aluminum alloy sheet for deep drawing of the present invention comprises the following specific processes:

[0044] (1) Ingredients:

[0045] Adjusting the solid-liquid ratio: Aluminum raw materials include solid aluminum and liquid aluminum. The aluminum raw materials are prepared according to the following mass percentages: 40% to 60% solid aluminum and 40% to 60% liquid aluminum. Preferably, 50% solid aluminum (solid material) and 50% liquid aluminum (aluminum water) are mixed to form aluminum raw materials. Solid aluminum includes aluminum alloy scrap and remelted aluminum ingots. When preparing the materials, the raw and auxiliary materials are checked to ensure that they are clean and free of oil and dirt. The process of completing solid-liquid batching in the smelting furnace is as follows:

[0046] Charging: The order is solid material (from small particles to large particles, i.e. first waste material and then remelting aluminum ingots, waste particles are small) → electrolytic aluminum liquid. When adding solid material, spread it evenly from the middle position to both sides, and do not pile it up on both sides of the furnace to ensure uniform melting;

[0047] When the aluminum liquid is timely and sufficient (i.e. the aluminum liquid is ready), after all the solid materials and aluminum liquid are loaded into the furnace, the furnace door is closed and the furnace is ignited to heat up, and the furnace temperature is 1050℃;

[0048] After the charge collapses, turn on the electromagnetic stirrer to accelerate melting, and measure the temperature of the melt, which is 740-760°C.

[0049] Among them, when waiting for molten aluminum (during the preparation process), after the solid material is loaded into the furnace, the furnace door is closed and the fire is turned on to melt the solid material, but be careful not to overheat the melt temperature after adding molten aluminum. Appropriate melting temperature and solid material ratio increase the melt supercooling, which is beneficial to recrystallization nucleation, refine casting grains, and improve deep drawing performance. The existing process solid-liquid ratio is 25-35% solid material and 65-75% molten aluminum. Increasing the solid material ratio can improve the defect of insufficient nucleation of electrolytic aluminum water and effectively refine the grains.

[0050] Alloy composition adjustment: Add corresponding alloying raw materials according to the alloy composition ratio, alloy element ratio: Si 0-0.2%; Fe 0-0.3%; Cu 0-0.05%; Mn 0.5-0.8%; Mg 4.1-4.6%; Cr0.05-0.15%; Zn0.015-0.025%; Ti 0.01-0.02%; single impurity ≤ 0.05%; total impurity ≤ 0.15%. Control each component according to the national standard of 5083 alloy. It can be adjusted according to the following preferred ratio: Si 0-0.08%; Fe 0.15-0.22%; Mn0.65-0.75%; Mg 4.3-4.4%; Cr 0.05-0.15%; Zn 0.015-0.025%; Ti 0.01-0.02%. Among them, aluminum-manganese master alloy can be used to adjust the Mn content. The specific process of adjusting each component is:

[0051] a. Pre-analysis: When all the solid materials are melted and the electromagnetic stirrer is turned on for stirring for 20 minutes, samples are taken for component pre-analysis. The sampling positions are one mushroom sample each in the middle and on both sides of the furnace.

[0052] b. Alloying: Alloying temperature is 740-750℃. Calculate the type and weight of metal additives (such as metal elements, magnesium ingots) or intermediate alloys (such as aluminum-manganese alloys) according to the preliminary analysis results, add them evenly into the furnace, and start the alloying reaction for 20-30 minutes (determined by the added weight). Then turn on the electromagnetic stirrer and stir for 20 minutes. After stirring, take samples for component analysis, adjust the composition again according to the analysis results, and cast in a converter when the composition meets the process requirements.

[0053] Si is a harmful element in 5083 alloy, and forms Mg2Si phase (brittle phase) with Mg element. The excess Mg element in high magnesium alloy reduces the solubility of Mg2Si in the matrix, and gathers at the grain boundary in a free state, reducing the elongation performance of the material. Fe forms a hardly soluble compound with Mn and Cr in 5083 alloy. This phase is hard and brittle, reducing the plasticity of the material. Cu reduces the corrosion resistance of the material and controls the lower limit of the national standard. That is, in 5083 aluminum alloy, Si, Fe and Cu are all harmful elements, which can easily reduce the quality of aluminum alloy products. The less the content, the better. The content of Si, Fe and Cu can be 0.

[0054] Mn forms MnAl6 series manganese-aluminum alloy compounds with Al in 5083 alloy, which increases the recrystallization temperature and prevents grain coarsening. At the same time, it has a significant effect on increasing the yield strength, controlling the upper and lower limits, and can effectively improve the stamping wrinkling defects.

[0055] Mg is the main strengthening phase in 5083 alloy, existing in solid solution and β phase (Mg2Al3 and Mg5Al8); if the Mg content is too low, the material strength is insufficient, and if the Mg content is too high, the solubility of Si in the matrix is ​​reduced, causing it to exist in a free state at the grain boundary, increasing the brittleness of the material. At the same time, if the Mg content is too high, it is easy to form more solid solution atomic clusters, pin dislocations, reduce the yield strength of the material, and easily cause stamping wrinkling defects.

[0056] The alloy composition is adjusted online in the smelting furnace, because the aluminum raw material contains aluminum alloy scrap, which contains some alloy elements. That is, the content of each element is analyzed by online detection of the molten metal, and then precise adjustment is made.

[0057] (2) Melting

[0058] The smelting process specifically includes:

[0059] Melting: 5083 aluminum alloy raw materials are added into a melting furnace and melted into aluminum alloy melt;

[0060] Sodium removal: adding a sodium removal agent to the above smelting furnace, the amount of the sodium removal agent added is 3-5‰ of the total amount of the aluminum alloy raw materials, and the sodium removal time is 35-45 minutes;

[0061] First refining: After sodium removal, add refining agent to the smelting furnace. The amount of refining agent added is 1.5-2.5‰ of the total amount of aluminum alloy raw materials. Keep the temperature at 740-760℃ and the refining time is 55-65min.

[0062] Second refining: the aluminum alloy melt after the first refining is sent to a holding furnace, kept at 730-750°C, and the refining time is 55-65 minutes.

[0063] In the existing process, the amount of sodium removal agent is 2‰, the amount of particle refining agent is 1.2‰, the melting furnace is refined once, and the refining time is 40 minutes. In the present invention, the Na content in the melt can be reduced by increasing the amount of sodium removal agent, and the adjusted Na content is reduced from 5ppm to 3ppm, which can effectively reduce the sodium brittleness defect of the alloy and improve the deep drawing performance of the material; increasing the amount of refining agent, refining time and refining in a holding furnace once can effectively remove impurity elements in the melt, reduce the generation of crack sources during stamping, improve deep drawing performance, reduce the pinning of impurity elements on dislocations, and reduce the occurrence of stamping wrinkling defects.

[0064] The smelting process is specifically operated as follows:

[0065] a. Sodium removal in smelting furnace: Use 3-5‰ sodium removal agent to remove sodium from the melt through high-purity argon gas and refining furnace. During the powder spraying process, pay attention to controlling the powder spraying time to 20-30 minutes and the sodium removal time to 35-45 minutes. For example, if the aluminum alloy raw material is 80 tons, 300kg sodium removal agent can be used.

[0066] b. Refining in smelting furnace: The melt refining temperature is controlled at 740-760℃, the refining agent dosage is 1.5-2.5‰, the refining time is 55-65min, and multiple refining furnaces can be used simultaneously. The time for spraying granular refining agent is controlled at 15-20min. The refining tube is inserted into the middle and lower part of the melt and moves slowly without leaving dead corners. The bubbles are like boiling water, and the melt tumbling height does not exceed 100mm.

[0067] c. Slag removal from smelting furnace: Slag removal begins after refining is completed. Avoid waves when removing slag. Slag on the surface of the melt should be removed to the furnace edge at the furnace door and stay there for 3 to 10 seconds before removing.

[0068] d. Converter: Converter can be used only after melt composition is adjusted to meet the standards. The melt temperature during converter operation is 730-750℃.

[0069] e. Refining in holding furnace: The melt refining temperature is controlled at 730-750℃, and the refining method is the same as that of the smelting furnace. 20 minutes before the end of refining, titanium boron blocks (to refine the grains) are added according to the chemical composition test report, and the titanium content of the holding furnace is controlled at 0.006-0.008%.

[0070] f. Slag removal from holding furnace: The operation is the same as that of smelting furnace. Make sure there is no floating slag on the surface after slag removal.

[0071] g. Standing: After slag removal, let it stand for 50 minutes before casting. If a sudden failure occurs and the standing time exceeds 120 minutes, argon gas must be used to supplement refining for 30 minutes, and then continue to stand for 50 minutes after refining.

[0072] (3) Casting

[0073] Before casting, the chute must be cleaned and painted with boron nitride. After painting, no residual powdery debris should be left in the chute, and the chute must be baked. Online grain refinement uses aluminum titanium boron wire (Al-5Ti-1B) for online grain refinement, online double wire addition, and the online addition amount of aluminum titanium boron wire is 170-220kg. Casting temperature: 690-700℃; casting speed: 46-48mm / min; cooling water flow: 280-300m 3 / h; cooling water temperature: 25~40℃; liquid level height 60~70mm.

[0074] (4) Sawing and milling

[0075] Defective parts such as the head and tail and the surface of the ingot are removed by sawing and milling. After the ingot is milled, there should be no sticky aluminum, pores, oxide scale, cutting fluid, slag inclusion, corrosion, surface cracks, aluminum chips, and dirt on the surface.

[0076] (5) Homogenization

[0077] The homogenization process adopts a three-stage heating process:

[0078] The first stage of equalization: furnace gas temperature 490 ~ 510 ℃, metal temperature 440 ~ 460 ℃, keep warm for 4 ~ 8 hours;

[0079] The second stage of equalization: furnace gas temperature 550-570℃, metal temperature 510-530℃, keep warm for 12-16h;

[0080] The third stage of equalizing: furnace gas temperature 480 ~ 500 ℃, metal temperature 475 ~ 485 ℃, keep warm for 2 ~ 4h.

[0081] The existing process uses a furnace gas temperature of 560℃, a metal temperature of 540℃, and is kept warm for 8 hours for homogenization treatment; the homogenization temperature is high, and the metal temperature overheating during the annealing process is easy to cause overburning, which is easy to reduce the plasticity of the material; the annealing time is short, the diffusion of segregated atoms is insufficient, the uniformity of the organization is poor, and the anisotropy is obvious during the stamping process, which is easy to cause cracking defects. In the present invention, a three-stage heating method is adopted for the aluminum alloy ingot after casting and sawing and milling. The furnace gas temperature of the first stage is low and the heating speed is slow, which can effectively reduce the temperature difference of the ingot, and at the same time prolong the annealing time, so that the segregated atoms are fully diffused and the uniformity of the ingot is improved; the second stage of low-temperature annealing can ensure that the segregated atoms are fully diffused, and can prevent the homogenization temperature from being too high, causing the ingot to be overburned, resulting in the problem of reducing the plasticity of the material; the third stage is cooled to 480℃ and kept warm before rolling out of the furnace. Rolling at this temperature can improve the aluminum sticking during the rolling process and improve the plate surface quality.

[0082] (6) Hot rolling

[0083] The hot rolling start temperature is 450-500℃, and the final rolling temperature is 300-350℃, preferably 330-350℃. The thickness of the intermediate plate before hot rolling is 30mm, and the thickness of the finished product after finishing rolling is 4.0-6.0mm. Before rolling, check all nozzles and clean the roller system to ensure clean production. Check the emulsion index to meet the production process requirements of the oxidized material.

[0084] (7) First cold rolling

[0085] The hot-rolled billet has a thickness of 4.0 to 6.0 mm, and the first cold rolling is 5 to 6 passes to 0.9 to 1.4 mm, preferably 1.0 to 1.2 mm. The cold rolling work roll has a convexity of +0.02 mm and a roughness of 0.4 to 0.45 um. Before rolling, the roll system is cleaned, the nozzle and the oil quality are checked to ensure that the rolling mill conditions meet the rolling requirements of the product; wherein, the total processing rate of the first cold rolling is greater than 70%. The first cold rolling uses a high processing rate to effectively crush the grains, increase nucleation, and refine the grains during intermediate annealing. At the same time, the large deformation can accumulate a large amount of distortion energy in the material, which can achieve low-temperature rapid annealing, refine the grains, and improve the stamping performance of the material. After the first cold rolling, the billet is cleaned to effectively remove the residue on the surface of the billet, ensuring the cleanliness of the billet and the smooth progress of subsequent processing.

[0086] (8) Intermediate annealing

[0087] The intermediate annealing process adopts two-stage low-temperature rapid annealing:

[0088] The first stage of intermediate annealing: furnace gas temperature 230 ~ 250 ℃, metal temperature 140 ~ 160 ℃, keep warm for 3 ~ 6 hours;

[0089] The second stage intermediate annealing: furnace gas temperature 390 ~ 410 ℃, metal temperature 310 ~ 320 ℃, keep warm for 3 ~ 5h.

[0090] Among them, low-temperature rapid annealing can effectively prevent grain growth, refine grains, and improve material stamping performance. During the annealing process, the temperature measurement annealing is performed by punching. The temperature of the thermocouple used for temperature measurement needs to be calibrated in advance. The hole is punched on the coil in the middle position. The hole is 30-35mm from the sleeve and the hole depth is 70-80mm. The thermocouple must be inserted to the bottom of the hole and plugged with iron wire or steel chisel without looseness. Record the furnace gas and metal temperature every 60 minutes. When the temperature of each zone is stable, the temperature difference is within ±3℃.

[0091] (9) Second cold rolling

[0092] The second cold rolling is rolled to the finished product thickness in one pass, and the finished product thickness tolerance is controlled within the customer's requirements (the tolerance is generally controlled within ±0.04mm), and the plate shape is controlled to have no obvious looseness and rib waves. The final finished product thickness is 0.8-1.0mm. After intermediate annealing, it is preferred to reserve a 10-20% processing rate for the second cold rolling. At this processing rate, the material is in a low-energy state, the driving force for recrystallization nucleation is insufficient, and the high-temperature annealed material recovers and the grains grow. The elongation is significantly increased, but the recrystallization cannot be completely completed, and the yield strength is high, thereby achieving a high yield strength ratio and high elongation 5083 aluminum alloy. After the second cold rolling, the billet is cleaned to effectively remove the residue on the surface of the billet, ensuring the cleanliness of the billet and the smooth progress of subsequent processing.

[0093] (10) Finished product annealing

[0094] The finished product annealing process adopts two-stage high temperature slow annealing:

[0095] The first stage of finished product annealing: furnace gas temperature 330 ~ 350 ℃, metal temperature 230 ~ 250 ℃, heat preservation 4 ~ 6h;

[0096] The second stage of finished product annealing: furnace gas temperature 370 ~ 390 ℃, metal temperature 320 ~ 340 ℃, keep warm for 3 ~ 5h.

[0097] This process has a long annealing time and a high annealing temperature, which can allow the material to fully complete the recovery and grain growth process, increase the material elongation, and improve the material stamping effect.

[0098] (11) Cutting: The prepared 5083 aluminum alloy sheet for deep drawing is cut and packaged.

[0099] The present invention solves the wrinkling and cracking quality defects of such products during the stamping process by controlling the melt quality, adjusting the specific gravity of alloy elements, refining grains, homogenizing treatment, adjusting the heat treatment process and adjusting the process route, thereby improving the product quality. The 5083 aluminum alloy sheet for deep drawing obtained by the present invention through the above-mentioned preparation method has a tensile strength of 310-325Mp, a yield strength of 160-200Mp, an elongation of 18-24%, and a yield strength ratio of 0.57-0.65. It has a high yield strength ratio and high elongation, can ensure that the material does not crack during stamping, and avoids the occurrence of stamping wrinkles.

[0100] The 5083 aluminum alloy sheet for deep drawing and the preparation method thereof of the present invention are further introduced below in conjunction with specific embodiments.

[0101] Example 1

[0102] Ingredients: 50% solid material and 50% aluminum liquid to prepare raw aluminum;

[0103] Alloy element adjustment ratio: Si 0.073%; Fe 0.201%; Mn 0.67%; Mg 4.33%; Cr 0.068%; Zn 0.0178%; Ti 0.0162%.

[0104] Melting: The melting temperature of the molten body is 745°C. After the alloying reaction time is 25 minutes, the electromagnetic stirrer is turned on for stirring for 20 minutes.

[0105] Sodium removal and refining: Sodium removal agent 4.0‰, granular refining agent 2.0‰, refining once in the smelting furnace and the holding furnace, the refining time is 60 minutes for both times, and the sodium removal time is 40 minutes. The melting temperature of the melting furnace is 745℃, and the melting temperature of the holding furnace is 740℃.

[0106] Casting: Aluminum titanium boron wire online addition amount 200kg. Casting temperature: 695℃; Casting speed: 46mm / min; Cooling water flow: 290m 3 / h; cooling water temperature: 30℃; liquid level height 65mm.

[0107] Sawing and milling: The end is not sawn, and the head is sawn 100 (+30 / -0) mm. The large surface of the milling surface is 15 mm / single side, and the bevel surface is 8 mm / single side.

[0108] Even fire:

[0109] The first stage of soaking: furnace gas temperature 500℃, metal temperature 450℃, keep warm for 5h;

[0110] The second stage of equalization: furnace gas temperature 560℃, metal temperature 520℃, keep warm for 12h;

[0111] The third stage of equalization: furnace gas temperature 490℃, metal temperature 480℃, keep warm for 3h.

[0112] Hot rolling: hot rolling starting temperature is 480℃, final rolling temperature is 330℃. The thickness of the intermediate plate is 30mm, and the thickness of the finished product is 5.0mm.

[0113] First cold rolling: The first cold rolling is 5 to 6 passes to a thickness of 1.18 mm, and the total processing rate of the first cold rolling is 77%. The crown of the cold rolling work roll is +0.02 mm and the roughness is 0.42 um.

[0114] Intermediate annealing:

[0115] The first intermediate annealing: furnace temperature 240℃, metal temperature 15℃, keep warm for 5h;

[0116] The second intermediate annealing: furnace gas temperature 400℃, metal temperature 315℃, keep warm for 4h.

[0117] Record the furnace gas and metal temperature every 60 minutes. When the temperature of each zone is stable, the temperature difference is within ±3℃. After the intermediate annealing is completed, take samples for metallographic analysis.

[0118] Second cold rolling: The second cold rolling is rolled to the finished product thickness of 1.0mm in one pass. The finished product thickness tolerance is controlled within the customer's requirements, and the plate shape is controlled to have no obvious looseness and rib waves. The processing rate of the second cold rolling is 15%.

[0119] Finished product annealing:

[0120] The first stage of finished product annealing: furnace gas temperature 340℃, metal temperature 240℃, keep warm for 5h;

[0121] The second stage of finished product annealing: furnace gas temperature 380℃, metal temperature 330℃, keep warm for 4h;

[0122] After the finished product is annealed, samples are taken for metallographic analysis.

[0123] In Example 1, the intermediate annealing was performed and the grains were sampled and tested, and the following results were obtained: Figure 1 The metallographic diagram of the aluminum alloy sheet shown in the figure shows that the grain size is level 8 and the structure is uniform, which meets the requirements of deep drawing material structure. After annealing of the finished product, the grain size is sampled and tested, and the following is obtained: Figure 2 The metallographic image of the aluminum alloy sheet shown shows a grain size of level 5. Compared with intermediate annealing, the grain size grows, the material elongation increases, and the material stamping effect is improved.

[0124] The finished product of the deep drawing 5083 aluminum alloy sheet obtained in Example 1 was subjected to a metal tensile test, and the following results were obtained: Figure 3 The force-displacement curve is shown in the figure, and the test results are shown in Table 1.

[0125] Table 1 Tensile test properties of the finished product of 5083 aluminum alloy sheet for deep drawing of Example 1

[0126] Dimensions (mm) 21.45*1.005 <![CDATA[Cross-sectional area (mm 2 )]]> 21.56 Original gauge length (mm) 50 Elastic modulus(Gpa) 13.56 Maximum force (kN) 6.78 Tensile strength(Mpa) 314 Lower yield stress(kN) 5.77 Lower yield strength(Mpa) 268 Gauge length after breaking (mm) 61.7 Elongation after break (%) 23.5 <![CDATA[Cross-sectional area after fracture (mm 2 )]]> 0.000 Sectional shrinkage (%) 100 Specified non-proportional extension force (kN) 3.89 Specified non-proportional elongation strength (Mpa) 180

[0127] As can be seen from Table 1, through experiments and analytical calculations, the tensile strength of the finished 5083 aluminum alloy plate of Example 1 is 314 MPa, the yield strength is 195 MPa, the elongation is 23.5%, and the yield strength ratio is 0.62. It has a high yield strength ratio and high elongation, which can ensure that the material does not crack during stamping and avoid the occurrence of stamping wrinkles.

[0128] like Figure 4 As shown, a cupping test was performed on the finished product of Example 1, and the maximum thinning rate of the cupping test was 5.2%, the anisotropy was small, and the crack resistance was good.

[0129] Example 2

[0130] Ingredients: 45% solid material and 55% aluminum liquid to prepare raw aluminum;

[0131] Alloy element adjustment ratio: Si 0.078%; Fe 0.258%; Mn 0.559%; Mg 4.48%; Cr0.0711%; Zn 0.0199%; Ti 0.0182%.

[0132] Even fire:

[0133] The first stage of soaking: furnace gas temperature 490℃, metal temperature 440℃, keep warm for 4h;

[0134] The second stage of equalization: furnace gas temperature 550℃, metal temperature 510℃, keep warm for 12h;

[0135] The third stage of equalization: furnace gas temperature 480℃, metal temperature 475℃, keep warm for 2h.

[0136] Hot rolling: hot rolling starting temperature is 482℃, final rolling temperature is 336℃. The thickness of the intermediate plate is 28mm, and the thickness of the finished product is 4.0mm.

[0137] First cold rolling: The first cold rolling is performed in 5 passes to a thickness of 1.17 mm, and the total processing rate of the first cold rolling is 71%.

[0138] Intermediate annealing:

[0139] The first intermediate annealing: furnace temperature 240℃, metal temperature 15℃, keep warm for 5h;

[0140] The second intermediate annealing: furnace gas temperature 400℃, metal temperature 315℃, keep warm for 4h.

[0141] Second cold rolling: The second cold rolling is rolled to a finished product thickness of 1.0 mm in one pass. The processing rate of the second cold rolling is 15%.

[0142] Finished product annealing:

[0143] The first stage of finished product annealing: furnace gas temperature 340℃, metal temperature 240℃, keep warm for 5h;

[0144] The second stage of finished product annealing: furnace gas temperature 380℃, metal temperature 330℃, keep warm for 4h.

[0145] The finished product of the deep drawing 5083 aluminum alloy sheet obtained in Example 2 was subjected to a metal tensile test, and the following results were obtained: Figure 5 The force-displacement curve is shown in the figure, and the test results are shown in Table 2.

[0146] Table 2 Tensile test properties of the finished product of 5083 aluminum alloy sheet for deep drawing of Example 2

[0147] Dimensions (mm) 11.90*1.005 <![CDATA[Cross-sectional area (mm 2 )]]> 11.96 Original gauge length (mm) 50 Elastic modulus(Gpa) 18.52 Maximum force (kN) 3.69 Tensile strength(Mpa) 309 Lower yield stress(kN) 2.21 Lower yield strength(Mpa) 185 Gauge length after breaking (mm) 61.0 Elongation after break (%) 22.0 <![CDATA[Cross-sectional area after fracture (mm 2 )]]> 0.000 Sectional shrinkage (%) 100 Specified non-proportional extension force (kN) 2.21 Specified non-proportional elongation strength (Mpa) 185

[0148] As shown in Table 2, through experiments and analytical calculations, the tensile strength of the 5083 aluminum alloy sheet product of Example 2 is 309 MPa, the yield strength is 185 MPa, the elongation is 22.0%, and the yield strength ratio is 0.60, which can meet the stamping requirements of the battery cover sheet of new energy vehicles, and the surface after stamping is good. The specific product after stamping is as follows Figure 6 shown.

[0149] Example 3

[0150] Ingredients: 47% solid material and 53% aluminum liquid to prepare raw aluminum;

[0151] Alloy element adjustment ratio: Si 0.073%; Fe 0.201%; Mn 0.67%; Mg 4.33%; Cr 0.068%; Zn 0.0178%; Ti 0.0162%.

[0152] Even fire:

[0153] The first stage of soaking: furnace gas temperature 510℃, metal temperature 460℃, keep warm for 8h;

[0154] The second stage of equalization: furnace gas temperature 570℃, metal temperature 530℃, keep warm for 16h;

[0155] The third stage of equalization: furnace gas temperature 500℃, metal temperature 485℃, keep warm for 4h.

[0156] Hot rolling: hot rolling starting temperature is 483℃, final rolling temperature is 334℃. The thickness of the intermediate plate is 32mm, and the thickness of the finished product is 6.0mm.

[0157] First cold rolling: The first cold rolling is 6 passes to a thickness of 1.1 mm, and the total processing rate of the first cold rolling is 82%.

[0158] Intermediate annealing:

[0159] The first intermediate annealing: furnace temperature 240℃, metal temperature 15℃, keep warm for 5h;

[0160] The second intermediate annealing: furnace gas temperature 400℃, metal temperature 315℃, keep warm for 4h.

[0161] Second cold rolling: The second cold rolling is rolled in one pass to a finished product thickness of 0.9 mm, and the processing rate of the second cold rolling is 20%.

[0162] Finished product annealing:

[0163] The first stage of finished product annealing: furnace gas temperature 340℃, metal temperature 240℃, keep warm for 5h;

[0164] The second stage of finished product annealing: furnace gas temperature 380℃, metal temperature 330℃, keep warm for 4h.

[0165] The finished product of the deep drawing 5083 aluminum alloy sheet obtained in Example 3 was subjected to a metal tensile test, and the following results were obtained: Figure 7 The force-displacement curve is shown in the figure, and the test results are shown in Table 3.

[0166] Table 3 Tensile test properties of the finished product of 5083 aluminum alloy sheet for deep drawing of Example 3

[0167] Dimensions (mm) 11.81*0.902 <![CDATA[Cross-sectional area (mm 2 )]]> 10.65 Original gauge length (mm) 50 Elastic modulus (Gpa) 15.76 Maximum force (kN) 3.33 Tensile strength(Mpa) 313 Lower yield stress(kN) 1.97 Lower yield strength(Mpa) 185 Gauge length after breaking (mm) 60.7 Elongation after break (%) 21.5 <![CDATA[Cross-sectional area after fracture (mm 2 )]]> 0.000 Sectional shrinkage (%) 100 Specified non-proportional extension force (kN) 1.97 Specified non-proportional elongation strength (Mpa) 185

[0168] As shown in Table 3, through experiments and analytical calculations, the tensile strength of the 5083 aluminum alloy plate product of Example 3 is 313 MPa, the yield strength is 185 MPa, the elongation is 21.5%, and the yield strength ratio is 0.59, which meets the stamping requirements of luggage materials, and the surface after stamping is good. The specific product after stamping is as follows Figure 8 shown.

[0169] In summary, through testing and analysis of the finished 5083 aluminum alloy sheets for deep drawing prepared in Examples 1-3, it can be seen that the 5083 aluminum alloy sheets for deep drawing prepared in the present invention have a high yield strength ratio and high elongation, which can ensure that the 5083 aluminum alloy sheets do not crack during stamping, and also avoid the occurrence of wrinkling during stamping, and the surface after stamping is good.

[0170] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to the technical contents disclosed above without departing from the scope of the technical solution of the present invention, which are equivalent embodiments of equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a 5083 aluminum alloy sheet for deep drawing, characterized in that: The process of batching, melting, casting, sawing and milling, homogenization, hot rolling, first cold rolling, intermediate annealing, second cold rolling, finished product annealing and slitting is adopted in sequence for preparation; The homogenization treatment adopts a three-stage heating process: The first stage of equalization: furnace gas temperature 490 ~ 510 ℃, metal temperature 440 ~ 460 ℃, keep warm for 4 ~ 8 hours; The second stage of equalization: furnace gas temperature 550-570℃, metal temperature 510-530℃, keep warm for 12-16h; The third stage of equalizing: furnace gas temperature 480 ~ 500 ℃, metal temperature 475 ~ 485 ℃, keep warm for 2 ~ 4h.

2. The method for preparing a 5083 aluminum alloy sheet for deep drawing according to claim 1, characterized in that: The ingredients are prepared according to the following alloy element mass percentages: Si 0-0.2%; Fe 0-0.3%; Cu 0-0.05%; Mn 0.5-0.8%; Mg 4.1-4.6%; Cr 0.05-0.15%; Zn 0.015-0.025%; Ti 0.01-0.02%; single impurity ≤0.05%; total impurities ≤0.15%; the balance is Al.

3. The method for preparing a 5083 aluminum alloy sheet for deep drawing according to claim 1, characterized in that: In the batching process, the aluminum raw material includes solid aluminum and liquid aluminum, and the aluminum raw material is prepared according to the following mass percentages: 40% to 60% solid aluminum and 40% to 60% liquid aluminum.

4. The method for preparing a 5083 aluminum alloy sheet for deep drawing according to claim 1, characterized in that: The smelting process specifically includes: Melting: 5083 aluminum alloy raw materials are added into a melting furnace to melt into aluminum alloy melt, and the melt temperature is 740-760℃; Sodium removal: adding a sodium removal agent to the above smelting furnace, the amount of the sodium removal agent added is 3-5‰ of the total amount of the aluminum alloy raw materials, and the sodium removal time is 35-45 minutes; First refining: After sodium removal, add refining agent to the smelting furnace. The amount of refining agent added is 1.5-2.5‰ of the total amount of aluminum alloy raw materials. Keep the temperature at 740-760℃ and the refining time is 55-65min. Second refining: the aluminum alloy melt after the first refining is sent to a holding furnace, kept at 730-750°C, and the refining time is 55-65 minutes.

5. The method for preparing a 5083 aluminum alloy sheet for deep drawing according to claim 1, characterized in that: The hot rolling start temperature is 450-500°C, and the final rolling temperature is 300-350°C.

6. The method for preparing a 5083 aluminum alloy sheet for deep drawing according to claim 1, characterized in that: The processing rate of the first cold rolling is ≥70%, and the thickness of the product obtained by the first cold rolling is 0.9-1.4 mm; the processing rate of the second cold rolling is 10-20%, and the thickness of the product obtained by the second cold rolling is 0.8-1.0 mm.

7. The method for preparing a 5083 aluminum alloy sheet for deep drawing according to claim 1, characterized in that: The intermediate annealing process adopts two-stage low-temperature rapid annealing: The first stage of intermediate annealing: furnace gas temperature 230 ~ 250 ℃, metal temperature 140 ~ 160 ℃, keep warm for 3 ~ 6 hours; The second stage intermediate annealing: furnace gas temperature 390 ~ 410 ℃, metal temperature 310 ~ 320 ℃, keep warm for 3 ~ 5h.

8. The method for preparing a 5083 aluminum alloy sheet for deep drawing according to claim 1, characterized in that: The finished product annealing process adopts two-stage high temperature slow annealing: The first stage of finished product annealing: furnace gas temperature 330 ~ 350 ℃, metal temperature 230 ~ 250 ℃, heat preservation 4 ~ 6h; The second stage of finished product annealing: furnace gas temperature 370 ~ 390 ℃, metal temperature 320 ~ 340 ℃, keep warm for 3 ~ 5h.

9. A 5083 aluminum alloy sheet for deep drawing, characterized in that: The 5083 aluminum alloy sheet for deep drawing is prepared by the preparation method as described in any one of claims 1 to 8.

10. The 5083 aluminum alloy sheet for deep drawing according to claim 9, characterized in that: The 5083 aluminum alloy sheet for deep drawing has a tensile strength of 310-325Mp, a yield strength of 160-200Mp, an elongation of 18-24%, and a yield strength ratio of 0.57-0.65.

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