Method for preparing a toughened traffic 6016 aluminum alloy

Abstract

The application discloses a kind of preparation methods of toughening traffic 6016 aluminum alloy, belong to metal material preparation technical field;Including the following steps: alloy uses the aluminum ingot with purity more than 99.9%, intermediate alloy Al-20Si, Al-10Mg, Al-50Cu, Al-10Mn, Al-20Cr, Al-20Zn, Al-20Er, Al-5Ti-B, according to the proportioning of element mass ratio Si:Mg:Cu:Mn:Fe:Cr:Zn:Ti:Er=(1.0~1.5):(0.25~0.6):(<0.20):(<0.50):(<0.10):(<0.20):(<0.15):(0.15,0.30,0.45) smelting, the cast ingot that smelts is homogenized annealing, rolling is obtained The plate material with the thickness of 1mm, then after heat treatment obtains the aluminum alloy plate of T4P state.The application adds rare earth element Er, heat treatment toughening traffic 6016 aluminum alloy, so that aluminum alloy has preferable plasticity under the premise of maintaining high hardness and high strength, is expected to improve the strength and plasticity of 6016 aluminum alloy in practical application, conducive to the wide application of 6016 aluminum alloy.

Description

Technical Field

[0001] This invention relates to the field of metallic materials technology, and in particular to a method for preparing a strong and toughened 6016 aluminum alloy for transportation applications. Background Technology

[0002] Lightweighting of automobiles is a major development direction for achieving energy conservation and emission reduction in the automotive industry, and also an important means to enhance the competitiveness of automotive brands. Due to its low density and high specific strength, aluminum alloy has become a primary lightweight material for automobiles. Among them, 6016 aluminum alloy is a heat-treatable aluminum alloy, and 6016 aluminum alloy sheets are currently used in the manufacture of car doors, windows, and body panels. It exhibits low yield strength after solution treatment and water quenching, good stamping performance, and its strength is further enhanced during subsequent painting processes. Its excellent stamping formability and strong paint hardening ability perfectly meet the requirements of automotive body panels, thus attracting increasing attention in recent years. However, the production cost of 6016 aluminum alloy sheets for transportation using traditional processes is 2 to 4 times that of traditional automotive body steel sheets, and its deep-drawing performance is still somewhat inferior to low-carbon steel sheets. This seriously hinders the large-scale application of 6016 aluminum alloy body panels in automobiles. Therefore, the shortcomings in strength and plasticity, as well as the excessively high production cost of existing 6016 aluminum alloy for transportation, urgently need to be addressed. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a strong and toughened 6016 aluminum alloy for transportation, which solves the problems of insufficient strength and plasticity and excessively high preparation cost of existing 6016 aluminum alloys for transportation.

[0004] The technical solution of this invention is: a method for preparing a strong and toughened 6016 aluminum alloy for transportation, characterized by comprising the following steps:

[0005] (1) Batching: Weigh aluminum ingots and weigh the master alloy of each element according to the mass ratio of alloy elements Si:Mg:Cu:Mn:Fe:Cr:Zn:Ti:Er=(1.0~1.5):(0.25~0.6):(<0.20):(<0.50):(<0.10):(<0.20):(<0.15):(<0.50). Cut the master alloy into small pieces.

[0006] (2) Smelting: Place the prepared raw materials into a graphite crucible and dry them together in a box-type muffle furnace at 280-320°C for 0.5-1 hour; then place the pure aluminum ingot and the graphite crucible together into a pit-type resistance furnace and heat the furnace to 780-820°C. When the furnace is 75-80% melted, add Al-20Er and covering agent. When the furnace temperature drops to 750-760°C, add Al-10Mn, Al-20Zn, Al-20Cr, Al-20Si, Al-10Mg, and Al-50Cu in sequence. Then, when the furnace temperature drops to 730-740°C, add Al-5Ti-B. After all the raw materials have melted, degas, let stand, and remove slag. When the furnace temperature drops to 700-720°C, take out the crucible and pour the alloy solution into a mold to cast ingots.

[0007] (3) Homogenization: The ingot is placed in a box-type resistance furnace for homogenization annealing at a temperature of 550-600℃ for 8-10 hours.

[0008] (4) Rolling: The homogenized annealed ingot is preheated at 550-580℃, and then hot rolling and cold rolling are performed respectively to obtain rolled plate.

[0009] (5) Heat treatment: The rolled plate is first subjected to solution treatment, and after solution treatment, it is taken out and water quenched at room temperature, followed by pre-aging treatment and artificial aging.

[0010] Furthermore, the purity of the aluminum ingot and the intermediate alloys Al-20Si, Al-10Mg, Al-50Cu, Al-10Mn, Al-20Cr, Al-20Zn, Al-20Er, and Al-5Ti-B is all above 99.9%.

[0011] Furthermore, in step (2), the covering agent is a mixture of MgCl2, BaCl2, and KCl, with a weight percentage of MgCl2:BaCl2:KCl = 19:3:15; this effectively isolates the aluminum melt from air, prevents secondary oxidation of the aluminum melt, reduces inclusions in the molten steel, and improves the quality of the aluminum alloy casting.

[0012] Furthermore, in the intermediate alloy Al-20Er, the mass content of Er in the aluminum alloy includes 0.15%, 0.30%, and 0.45%.

[0013] Furthermore, in step (4), the ingot thickness is 20mm, the thickness after hot rolling is 4mm, and the rolled plate after cold rolling is 1mm.

[0014] Further, in step (5), the rolled plate is solution-treated in a box-type resistance furnace at a temperature of 550-580°C for 8-12 minutes. After solution treatment, the plate is taken out and water-quenched at room temperature for 5-8 minutes, followed by pre-aging treatment at 160-180°C for 5-10 minutes, and then artificial aging is performed at a temperature of 170-180°C for 50-60 minutes.

[0015] Preferably, in step (5), the rolled plate is solution-treated in a box-type resistance furnace at a temperature of 560°C for 10 minutes. After solution treatment, the plate is taken out and water-quenched at room temperature for 5 minutes, followed by pre-aging treatment at 170°C for 10 minutes, and then artificial aging is performed at a temperature of 175°C for 60 minutes.

[0016] The advantages of this invention are:

[0017] (1) The aluminum alloy preparation method provided by the present invention uses low-cost materials, and the preparation method and conditions are simple, which is conducive to industrial production.

[0018] (2) The Er-doped 6016 aluminum alloy prepared in this invention exhibits higher strength and toughness in the T4P state compared to commercially available aluminum alloys. When the Er doping amount is 0.30%, the tensile strength (Rm) increases by 7.38%, the yield strength (Rp0.2) increases by 4.09%, and the elongation δ increases by 8.90%. After artificial aging, the tensile strength (Rm) increases by 13.88%, the yield strength (Rp0.2) increases by 6.91%, and the elongation δ increases by 15.56%.

[0019] (3) The present invention uses rare earth element Er and heat treatment to strengthen and toughen 6016 aluminum alloy for transportation, so that the aluminum alloy has better plasticity while maintaining high hardness and high strength. It is expected to improve the strength and plasticity of 6016 aluminum alloy in practical applications and facilitate the widespread application of 6016 aluminum alloy. Attached Figure Description

[0020] Figure 1 The tensile stress-strain curve of the T4P state aluminum alloy of the present invention is shown.

[0021] Figure 2 This is a tensile fracture morphology diagram of the T4P state aluminum alloy of the present invention.

[0022] Figure 3 This is the tensile stress-strain curve of the aluminum alloy after artificial aging.

[0023] Figure labels: 0# is 6016 rolled aluminum alloy sheet purchased from the market; 1# is 6016 rolled aluminum alloy sheet with Er doping of 0.15%; 2# is 6016 rolled aluminum alloy sheet with Er doping of 0.30%; 3# is 6016 rolled aluminum alloy sheet with Er doping of 0.45%. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments and accompanying drawings, but this does not limit the scope of protection and application of the present invention.

[0025] A method for preparing a strong and toughened 6016 aluminum alloy for transportation applications includes the following steps:

[0026] (1) Batching: Weigh the master alloy of Si, Mg, Cu, Mn, Fe, Cr, Zn, Ti, and Er in the proportion of (1.0~1.5):(0.25~0.6):(<0.20):(<0.50):(<0.10):(<0.20):(<0.15):(0.15,0.30,0.45), with the remainder being aluminum ingots (purity of 99.9%).

[0027] (2) Smelting: Place the prepared raw materials into a graphite crucible and dry them together in a box-type muffle furnace at 300℃ for 0.5 hours; place the pure aluminum ingot and the graphite crucible together into a pit-type resistance furnace and heat the furnace to 780℃. When about 80% of the material has melted, add Al-10Er and a covering agent (MgCl2:BaCl2:KCl=19:3:15); when the furnace temperature drops to 750℃, add Al-10Mn, Al-20Zn, Al-20Cr, Al-20Si, Al-10Mg, and Al-50Cu in sequence. When the furnace temperature drops to about 730℃, add Al-5Ti-B. After all the raw materials have melted, degas, let stand, and remove slag. When the furnace temperature drops to 720℃, remove the crucible and pour the alloy solution into a mold to cast ingots.

[0028] (3) Homogenization: The ingot is placed in a box-type resistance furnace and homogenized and annealed at an annealing temperature of 550℃ for 10 hours to obtain a homogenized ingot.

[0029] (4) Rolling: The aluminum sheet is rolled using this process (preheating at 560℃ → hot rolling (20mm-4mm) → cold rolling (4mm-2mm-1mm) to obtain the rolled aluminum sheet; the sheets with Er doping of 0.15%, 0.30%, and 0.45% are numbered as 1#, 2#, and 3# respectively.

[0030] (5) Heat treatment

[0031] ①Solution treatment: The 6016 rolled aluminum alloy sheet (number 0#) purchased from the market and samples 1#, 2# and 3# were dissolved in a box-type resistance furnace at a temperature of 560℃ for 10 minutes. After solution treatment, the sheet was taken out and quenched in room temperature water.

[0032] ② Pre-aging: After solution treatment for 5 minutes, pre-aging treatment is carried out in a box-type resistance furnace at 170℃ for 10 minutes. After treatment, the alloy is taken out and air-cooled. After air cooling, it is naturally aged for 14 days to obtain T4P state aluminum alloy.

[0033] ③ Artificial aging: Artificial aging is carried out in a box-type resistance furnace at a temperature of 175℃ and a holding time of 60 minutes. After treatment, the aluminum alloy is removed and air-cooled to obtain artificially aged aluminum alloy.

[0034] The aluminum alloy samples were subjected to composition analysis, microhardness testing, tensile property testing, and fracture morphology analysis. Rolled sheets of grades 0#, 1#, 2#, and 3# were wire-cut into... The thin sections were polished with sandpaper and then subjected to elemental analysis using an X-ray fluorescence spectrometer (XRF). The results are shown in Table 1.

[0035] Table 1 Alloy Composition (wt%)

[0036]

[0037] The T4P state and artificially aged samples were processed into Thin slices were sanded and then subjected to hardness testing using a microhardness tester. The hardness values ​​at 5 points were measured and the average value was taken. As shown in Tables 2 and 3, compared with the alloy without rare earth element Er, the hardness of the aluminum alloy in the T4P state and artificially aged state was significantly improved after adding Er.

[0038] Table 2 Microhardness values ​​of T4P state samples

[0039]

[0040] Table 3 Microhardness values ​​of the samples after artificial aging

[0041]

[0042] The alloy samples in the T4P state and after artificial aging were machined into tensile specimens with a total length of 70 mm, a gauge length of 25 mm, a gauge width of 10 mm, and a thickness of 1 mm using wire cutting. The specimens were then stretched at a speed of 2 mm / min. The tensile properties are shown in Tables 4 and 5. As can be seen from Tables 4 and 5, the strength and plasticity of the alloy in the T4P state and after artificial aging were improved after the addition of Er.

[0043] Table 4 Tensile properties of T4P state specimens

[0044]

[0045]

[0046] Table 5 Tensile properties after artificial aging

[0047]

[0048] The morphology of the fracture surface of the tensile specimen was observed using scanning electron microscopy. Figure 2 It can be seen that the fracture surfaces of all three alloys have a large number of dimples, indicating that the fracture is a typical ductile fracture.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or simple substitutions conceived without creative effort should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a strong and toughened 6016 aluminum alloy for transportation, characterized in that, Includes the following steps: (1) Batching: Weigh aluminum ingots, weigh the intermediate alloy of each element, cut the intermediate alloy into small pieces. The composition of the prepared alloy is Si 1.17, Mg 0.56, Cu 0.10, Mn 0.13, Fe 0.06, Cr 0.03, Zn 0.17, Ti 0.02, Er 0.29; (2) Smelting: Place the prepared raw materials into a graphite crucible, and then dry them together in a box-type muffle furnace at 280-320℃ for 0.5-1 hour; subsequently, place the pure aluminum ingots and the graphite crucible together into a pit-type resistance furnace and heat the furnace to 780-820℃. When the ingots are 75-80% melted, add Al-20Er and a covering agent. When the furnace temperature drops to 750-760℃, add Al-10Mn, Al-20Zn, Al-20Cr, and Al- 20Si, Al-10Mg, Al-50Cu, and then when the furnace temperature drops to 730-740℃, Al-5Ti-B is added. After all the raw materials have melted, the mixture is degassed, allowed to stand, and slag is removed. When the furnace temperature drops to 700-720℃, the crucible is removed, and the alloy solution is poured into a mold to be cast into an ingot. The covering agent is a mixture of MgCl2, BaCl2 and KCl, with a weight percentage of MgCl2:BaCl2:KCl = 19:3:

15. (3) Homogenization: The ingot is placed in a box-type resistance furnace for homogenization annealing at a temperature of 550-600℃ for 8-10 hours. (4) Rolling: The homogenized annealed ingot is preheated at 550-580℃, and then hot rolling and cold rolling are performed respectively to obtain rolled plate. (5) Heat treatment: The rolled plate is first subjected to solution treatment, and after solution treatment, it is taken out and water quenched at room temperature, followed by pre-aging treatment and artificial aging. The ingot in (4) has a thickness of 20 mm, a thickness of 4 mm after hot rolling, and a thickness of 1 mm after cold rolling. The rolled sheet is solution-treated in a box-type resistance furnace at a temperature of 550–580℃ for 8–12 minutes. After solution treatment, it is taken out and water-quenched at room temperature for 5–8 minutes, followed by pre-aging treatment at 160–180℃ for 5–10 minutes, and then artificial aging is performed at a temperature of 170–180℃ for 50–60 minutes. In step (5), the rolled plate is dissolved in a box-type resistance furnace at a temperature of 560°C for 10 minutes. After dissolution, it is taken out and quenched in water at room temperature for 5 minutes, followed by pre-aging treatment at 170°C for 10 minutes. Then, artificial aging is performed at a temperature of 175°C for 60 minutes.

2. The method for preparing a strong and toughened 6016 aluminum alloy for transportation according to claim 1, characterized in that: The purity of the aluminum ingots and the intermediate alloys Al-20Si, Al-10Mg, Al-50Cu, Al-10Mn, Al-20Cr, Al-20Zn, Al-20Er, and Al-5Ti-B is all above 99.9%.

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