Preparation method of aluminum-based composite strip

Abstract

The invention discloses a preparation method of an aluminum-based composite strip. The preparation method comprises the following steps: preparing a skin material and a core material; stacking the first skin material, the core material and the second skin material in sequence to obtain a composite cast ingot; sequentially carrying out first heating and composite rolling on the composite cast ingot to obtain a composite plate blank; two opposite side faces of the composite plate blank are cut off; the cut composite plate blank is turned over by 90 degrees; sequentially carrying out secondary heating and hot rolling on the composite plate blank to obtain a hot-rolled strip; sequentially performing cold rough rolling, cleaning, intermediate annealing, cold finish rolling, cleaning, finished product annealing, trimming, cleaning and straightening on the hot-rolled strip to obtain a cold-rolled strip; longitudinally cutting the cold-rolled strip to obtain a coiled material; and the coiled material is sequentially subjected to anodic oxidation and electrolytic coloring, and the aluminum-based composite strip is obtained. According to the preparation method, the aluminum-based composite strip can have two different colors through one-time coloring.

Description

[Technical field]

[0001] The invention relates to the technical field of aluminum processing, and in particular to a method for preparing an aluminum-based composite strip. [Background technology]

[0002] After sandblasting, anodizing, electrolytic coloring and sealing treatment, a dense oxide film and uniform color can be formed on the surface of the aluminum alloy plate, which improves the corrosion resistance, wear resistance, insulation and ornamental properties of the aluminum alloy plate. It is now widely used in the appearance of 3C electronic appliances such as laptops and building wall decoration. Figure 1 shown.

[0003] In order to meet the aesthetic needs of consumers, a new anodizing process has been developed, which can produce two different colors on the surface of aluminum alloy plates, making them more beautiful when used for the appearance of 3C electronic appliances such as laptops. Figure 2 The new anodizing process is to immerse the entire aluminum alloy sheet in a coloring tank for the first coloring, and then immerse part of the aluminum alloy sheet in another coloring tank with different formula and different working conditions for the second coloring.

[0004] In summary, in order to produce two different colors on the surface of the aluminum alloy sheet in the related art, it is necessary to put it into two different coloring tanks for coloring twice in sequence. This new anodizing process is not only complicated but also costly. [Summary of the invention]

[0005] The purpose of the embodiment of the present invention is to provide a method for preparing an aluminum-based composite strip to solve the problem in the related art that in order to produce two different colors on the surface of an aluminum alloy plate, it is necessary to put it into two different coloring tanks for coloring twice in sequence, which leads to complex process and high cost.

[0006] An embodiment of the present invention provides a method for preparing an aluminum-based composite strip, which comprises the following steps:

[0007] Step S1, preparing a skin material and a core material respectively; wherein the skin material comprises a first skin material and a second skin material, and the constituent elements of the skin material and the constituent elements of the core material have at least one same element with a different content range;

[0008] Step S2, stacking and fixing the first skin material, the core material and the second skin material in order to obtain a composite ingot;

[0009] Step S3, sequentially performing a first heating and composite rolling on the composite ingot to obtain a composite slab; wherein the temperature of the composite ingot is maintained at 490-500° C. during heating;

[0010] Step S4, cutting off two opposite sides of the composite slab; wherein the cutting is calculated starting from the lowest point of the concave part of the side of the composite slab, and each side of the composite slab is cut off by 10-12 mm;

[0011] Step S5, turning the cut composite slab by 90°;

[0012] Step S6, heating and hot rolling the flipped composite slab for the second time in sequence to obtain a hot-rolled strip with a thickness of 5.0-8.0 mm; wherein the temperature of the composite slab during the second heating is 490-500° C., and the final rolling temperature of the hot rolling is 345±5° C.;

[0013] Step S7, sequentially performing cold rough rolling, first cleaning, intermediate annealing under nitrogen protection, cold finishing rolling, second cleaning, finished annealing under nitrogen protection, trimming, third cleaning and straightening on the hot-rolled strip to obtain a cold-rolled strip with a thickness of 0.5-3.0 mm;

[0014] Step S8, longitudinally cutting the cold-rolled strip to obtain a coil; wherein the coil at least includes a width of the skin material and a portion of the width of the core material;

[0015] Step S9: anodize and electrolytically color the coil in sequence to obtain an aluminum-based composite strip.

[0016] Preferably, in step S1, the core material is an aluminum alloy of one grade among 1 series, 3 series, 5 series, 6 series and 7 series aluminum alloys; the skin material and the core material are aluminum alloys of different series or aluminum alloys of the same series but different grades.

[0017] Preferably, in step S1, the leather material is prepared by melt casting, sawing, milling and wire brushing in sequence; or, the leather material is prepared by melt casting, sawing, milling, heating, hot rolling, cut-to-length sawing and slab wire brushing in sequence;

[0018] The core material is prepared by melt casting, sawing, milling and wire brush grinding in sequence; or, the core material is prepared by melt casting, sawing, milling, heating, hot rolling, cut-to-length sawing and slab wire brush grinding in sequence.

[0019] Preferably, the flat ingots obtained from the skin material and the core material in the melting and casting step both meet the following conditions:

[0020] Slag content less than or equal to 0.012mm 2 / Kg, the size of inclusions is less than or equal to 5μm, the hydrogen content is less than or equal to 0.12mL / 100g-Al, the coarse grain layer is less than or equal to 8mm, and the composition is uniform.

[0021] Preferably, after the skin material and the core material are obtained as flat ingots in the melting and casting step, the head of the flat ingot is cut off by 350-360mm, and the tail is cut off by 150-160mm; the large surface of the flat ingot obtained by the skin material in the melting and casting step close to the core material is milled by 15-20mm, and the large surface away from the core material is milled by 5-7mm; the large surface of the flat ingot obtained by the core material in the melting and casting step close to the first skin material and the large surface close to the second skin material are milled by 15-20mm respectively; the two opposite side surfaces of the flat ingot obtained by the skin material in the melting and casting step and the two opposite side surfaces of the flat ingot obtained by the core material in the melting and casting step are milled by 5-7mm respectively.

[0022] Preferably, the skin material and the core material satisfy the following conditions after milling the flat ingots obtained in the melting and casting step:

[0023] The thickness tolerance is less than or equal to 2mm, the large surface curvature is less than or equal to 2mm, the side curvature is less than or equal to 2mm, and the end curvature is less than or equal to 2mm.

[0024] Preferably, the bristle diameter of the wire brush used for polishing the leather material and the core material during the preparation process is 0.3-0.4 mm, and the assembly density is 100 wires / cm 2 -120 pieces / cm 2 , and the grinding process is equipped with an air pipe with compressed air. After grinding, a magnetic rod with a magnetic force greater than or equal to 12000GS is used to remove magnetic materials, and then a towel dipped in D30 cleaning agent is used to wipe and remove foreign matter.

[0025] Preferably, in step S3, the composite rolling preparation method comprises the following steps:

[0026] Step S31, hot rolling and laminating the heated composite ingot; wherein the hot rolling and laminating is performed by a hot rolling mill, and the emulsion spraying of the hot rolling mill is turned off before the hot rolling and laminating;

[0027] Step S32, transporting the composite ingot to between the working rolls of the hot rolling mill until half of the length of the composite ingot is transported to between the working rolls of the hot rolling mill, stopping the transport of the composite ingot and shutting down the hot rolling mill;

[0028] Step S33, adjusting the working rolls of the hot rolling mill to statically press the composite ingot; wherein the static rolling force is 120-200T;

[0029] Step S34, starting the hot rolling mill to perform composite rolling on the composite ingot without separating both ends from the working rolls, to obtain the composite slab; wherein the composite rolling includes five passes, and the reduction amounts of the five passes are 1mm, 3mm, 5mm, 7mm and 9mm respectively.

[0030] Step S35, after the composite rolling is completed, the emulsion spraying of the hot rolling mill is started and rolling is performed again until the composite slab is obtained.

[0031] Preferably, the maximum opening of the upper working roll and the lower working roll in the hot rolling mill is 1700 mm; in the step S4, the equipment used for cutting is a precision saw installed on the roller table of the hot rolling mill, and the maximum opening of the precision saw is 1700 mm.

[0032] Preferably, in step S3, the thickness of the core material is defined as H0, the thickness of the skin material is defined as H1, the thickness of the composite slab is defined as H3, and the thickness of the composite slab satisfies the following formula:

[0033] H3 / (2H1+H0)≥0.9.

[0034] Compared with the related art, the preparation method of the aluminum-based composite strip in the present invention limits the constituent elements of the skin material and the constituent elements of the core material to have a different content range of at least one same element, and composite-rolls the skin material and the core material and then performs anodizing and electrolytic coloring, so that the aluminum-based composite strip can have two or more different colors through one coloring, which greatly simplifies its preparation process and reduces production costs.

Brief Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0036] Figure 1 A schematic diagram of a notebook shell of a single color in the related art;

[0037] Figure 2 A schematic diagram of a notebook shell with two different colors in the related art;

[0038] Figure 3 A schematic flow chart of the steps of a method for preparing an aluminum-based composite strip provided in an embodiment of the present invention;

[0039] Figure 4 A schematic diagram of the structure of a composite ingot in a method for preparing an aluminum-based composite strip provided in an embodiment of the present invention;

[0040] Figure 5 A schematic diagram of the structure of a composite slab after flipping in a method for preparing an aluminum-based composite strip provided by an embodiment of the present invention;

[0041] Figure 6 A schematic structural diagram of a hot-rolled strip in a method for preparing an aluminum-based composite strip provided by an embodiment of the present invention;

[0042] Figure 7 A schematic structural diagram of a coil in a method for preparing an aluminum-based composite strip provided by an embodiment of the present invention;

[0043] Figure 8 A schematic structural diagram of an aluminum-based composite strip in a method for preparing an aluminum-based composite strip provided in a specific embodiment of the present invention;

[0044] Fig. 9 A schematic structural diagram of an aluminum-based composite strip in a method for preparing an aluminum-based composite strip provided in a second specific embodiment of the present invention. [Specific implementation method]

[0045] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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 are within the scope of protection of the present invention.

[0046] An embodiment of the present invention provides a method for preparing an aluminum-based composite strip, which comprises the following steps:

[0047] S1. Prepare skin material and core material separately.

[0048] The leather material includes a first leather material and a second leather material, and the constituent elements of the leather material and the constituent elements of the core material have different content ranges of at least one same element.

[0049] The core material is an aluminum alloy of one of the grades of 1 series, 3 series, 5 series, 6 series and 7 series aluminum alloys, such as 1050, 3003, 5005, 5052, 5754, 5182, 5083, 6063 and 7075. The skin material and the core material can be aluminum alloys of different series, such as when the core material is 5052, the skin material is 1070. The skin material and the core material can also be aluminum alloys of the same series but different grades, such as when the core material is 5052, the skin material is 5005. The skin material and the core material can also be aluminum alloys of the same series and brand, but the content range of the same element is different. For example, when the core material is 5052-A, the element Cu therein is ≤0.003%, and when the skin material is 5052-B, the element Cu therein is 0.07-0.095%, that is, the element Cu content of the skin material is 23-31 times the element Cu content of the core material. This design can make the aluminum-based composite strip have two different colors through one coloring. The reason is that when the content of elements such as Si, Fe, Cu, Mn, Mg, Cr, and Zn in the aluminum alloy is different, the solid solution type in the aluminum alloy is different, and the type, content and size of the second phase are different. The product composition after anodizing and coloring is very complex, and may be mixed in the state of "single substance, oxide or intermetallic compound" and there are differences, which further affects the type, thickness and morphology of the oxide film layer, and finally leads to different reflections of light, that is, color difference occurs when observed with the naked eye, resulting in two different colors.

[0050] The leather material is prepared by melting, sawing, milling and wire brushing in sequence; or, the leather material is prepared by melting, sawing, milling, heating, hot rolling, cut-to-length sawing and slab wire brushing in sequence.

[0051] The core material is prepared by melt casting, sawing, milling and wire brush grinding in sequence; or, the core material is prepared by melt casting, sawing, milling, heating, hot rolling, cut-to-length sawing and slab wire brush grinding in sequence.

[0052] The flat ingots obtained from the skin material and the core material in the melting and casting step both meet the following conditions:

[0053] Slag content less than or equal to 0.012mm 2 / Kg, the size of inclusions is less than or equal to 5μm, the hydrogen content is less than or equal to 0.12mL / 100g-Al, the coarse grain layer is less than or equal to 8mm, and the composition is uniform. This ensures that the aluminum-based composite strip will not have excessive and basic defects such as material lines and stripes during subsequent anodizing.

[0054] The "large surface" described below refers to the upper surface and / or lower surface of the flat ingot obtained by the core material and / or skin material in the melting and casting step; the "side surface (or small surface)" refers to the left side surface and / or right side surface of the flat ingot obtained by the core material and / or skin material in the melting and casting step; the "end surface" refers to the front end (or head) or rear end (or tail) of the flat ingot obtained by the core material and / or skin material in the melting and casting step.

[0055] The skin material and the core material satisfy the following conditions after milling of the flat ingot obtained in the melting and casting step:

[0056] The thickness tolerance is less than or equal to 2mm, the large surface curvature is less than or equal to 2mm, the side curvature is less than or equal to 2mm, and the end curvature is less than or equal to 2mm. These conditions must be controlled because they will affect the process and effect of composite rolling, and will also affect the final anodizing and coloring effects, such as the width of different colors, the straightness of the boundary between the skin material and the core material, etc.

[0057] After the skin material and the core material are melted and cast to obtain a flat ingot, the head of the flat ingot is cut off by 350-360 mm, and the tail is cut off by 150-160 mm. This design can avoid excessive defects such as cracks, slag inclusions, looseness and element segregation at the head and tail of the flat ingot.

[0058] The large surface of the flat ingot obtained by the skin material in the step of melting and casting is milled 15-20mm near the core material, and the large surface away from the core material is milled 5-7mm; the large surface of the flat ingot obtained by the core material in the step of melting and casting is milled 15-20mm respectively near the first skin material and the large surface near the second skin material; the two opposite side surfaces of the flat ingot obtained by the skin material in the step of melting and casting and the two opposite side surfaces of the flat ingot obtained by the core material in the step of melting and casting are milled 5-7mm respectively. By milling the side surfaces, it is possible to avoid the defects of cracks, slag inclusions, looseness, coarse crystals and element segregation exceeding the standard on the side of the flat ingot, so as to ensure that the ingot does not crack during hot rolling; by milling the large surfaces of the skin material and the core material, it is possible to avoid the defects of cracks, slag inclusions, looseness, coarse crystals and element segregation exceeding the standard on the large surface of the flat ingot, so as to ensure that the ingot does not crack during hot rolling, and at the same time will not affect the effects of composite rolling, final anodizing and coloring.

[0059] The diameter of the bristles of the wire brush used for polishing the leather material and the core material during the preparation process is 0.3-0.4 mm, and the assembly density is 100 pieces / cm 2 -120 pieces / cm 2, and the grinding process is equipped with an air pipe with compressed air. After grinding, a magnetic bar with a magnetic force greater than or equal to 12000GS is used to remove magnetic substances, and then a towel dipped in D30 cleaning agent is used to wipe and remove foreign matter. The magnetic bar can absorb and remove aluminum powder generated on the upper and lower surfaces of the flat ingot or slab, while the towel can wipe and remove dust and other foreign matter. This design can better achieve metallurgical grade welding when the skin material and the core material are composited, and prevent subsequent cracks and holes from occurring at the interface between the skin material and the core material.

[0060] S2. Stacking and fixing the first skin material, the core material and the second skin material in this order to obtain a composite ingot.

[0061] Wherein, the structure of the composite ingot is as follows Figure 4 As shown, 1 is the first leather material, 2 is the core material, and 3 is the second leather material; the first leather material and the second leather material are respectively fixed to the gaps at the head, middle and tail of both sides of the core material by spot welding, and the length of the spot welding is 30-40mm. This design can facilitate the stacking and fixing of the first leather material, the core material and the second leather material.

[0062] S3, sequentially performing first heating and composite rolling on the composite ingot to obtain a composite slab.

[0063] During heating, the temperature of the composite ingot is maintained at 490-500°C, and the holding time is 2 hours.

[0064] The thickness of the core material is defined as H0, the thickness of the skin material is defined as H1, and the thickness of the composite slab is defined as H3. The thickness of the composite slab satisfies the following formula:

[0065] H3 / (2H1+H0)≥0.9.

[0066] The composite rolling preparation method comprises the following steps:

[0067] S31, hot rolling and cladding the heated composite ingot.

[0068] The hot rolling composite is performed by a hot rolling mill, and the emulsion spray of the hot rolling mill is turned off before the hot rolling composite. Turning off the emulsion spray of the hot rolling mill can better achieve metallurgical grade welding of the skin material and the core material during subsequent composite rolling, thereby preventing cracks and holes from occurring at the interface between the skin material and the core material, or even peeling and separation between the skin material and the core material.

[0069] The maximum opening of the upper working roll and the lower working roll in the hot rolling mill is 1700 mm. The opening between the working rolls of the hot rolling mill in the related art is generally 320-670 mm. In order to facilitate the smooth implementation of the preparation method under industrial mass production conditions, the maximum opening between the working rolls of the hot rolling mill must be limited to 1700 mm.

[0070] S32, transporting the composite casting to between the working rolls of the hot rolling mill until half of the length of the composite ingot is transported to between the working rolls of the hot rolling mill, stopping the transportation of the composite ingot and shutting down the hot rolling mill.

[0071] S33, adjusting the working rolls of the hot rolling mill to statically press the composite ingot.

[0072] Among them, the static pressing rolling force is 120-200T.

[0073] S34, starting the hot rolling mill to perform composite rolling on the composite ingot without both ends being separated from the working rolls, to obtain the composite slab.

[0074] The composite rolling process includes five passes, and the reduction amounts of the five passes are 1 mm, 3 mm, 5 mm, 7 mm and 9 mm, respectively. Of course, the composite rolling process and the reduction amount can be adjusted according to actual needs.

[0075] Step S35, after the composite rolling is completed, the emulsion spraying of the hot rolling mill is started and rolling is performed again until the composite slab is obtained.

[0076] Among them, the second rolling also belongs to the rolling part of the composite rolling. The difference from the rolling in steps S2-S4 is that the emulsion spraying of the hot rolling mill needs to be turned on.

[0077] S4, cutting off two opposite side surfaces of the composite slab.

[0078] The cutting is calculated from the lowest point of the concave part of the side of the composite slab, and each side of the composite slab is cut by 10-12mm, that is, each side is cut by 10-12mm from the lowest point toward the middle of the composite slab. This ensures that the end face of the composite slab is smooth, without metal or non-metal indentation, and without obvious knife marks.

[0079] The equipment used for cutting is a precision saw installed on the roller table of the hot rolling mill, and the maximum opening of the precision saw is 1700mm. In the related art, the roller table of the hot rolling mill is not equipped with a large precision saw. In order to facilitate the smooth implementation of the preparation method under industrial mass production conditions and to deal with sudden abnormal situations during the production process, a large precision saw device must be installed on the hot rolling mill.

[0080] Of course, according to actual needs, the equipment used for cutting can also be a milling machine.

[0081] S5, turning the cut composite slab by 90°.

[0082] The structure of the composite slab after flipping is as follows: Figure 5 As shown; a large slab turning machine is used for turning.

[0083] S6. The flipped composite slab is sequentially heated and hot-rolled for a second time to obtain a hot-rolled strip with a thickness of 5.0-8.0 mm.

[0084] Wherein, the structure of the hot-rolled strip is as follows Figure 6 As shown; during the second heating, the temperature of the composite slab is 490-500°C, the insulation time is 2h, and a heating furnace is used. Hot rolling is performed after the heating is completed.

[0085] The hot rolling process is the process of anodizing aluminum alloy strip, and the final rolling temperature of hot rolling is 345±5℃.

[0086] S7, the hot-rolled strip is sequentially subjected to cold rough rolling, first cleaning, intermediate annealing under nitrogen protection, cold finishing rolling, second cleaning, finished product annealing under nitrogen protection, trimming, third cleaning and straightening to obtain a cold-rolled strip with a thickness of 0.5-3.0 mm.

[0087] Among them, the process parameters and quality requirements of this step adopt the process parameters and quality requirements of aluminum alloy strip for anodizing.

[0088] S8. Slitting the cold-rolled strip to obtain a coil.

[0089] Wherein, the structure of the coil is as follows Figure 7 As shown, a is a structural schematic diagram including only the first leather material and the core material, and b is a structural schematic diagram including the first leather material, the core material and the second leather material; the coiled material at least includes the width of the leather material and a part of the width of the core material at the same time.

[0090] S9, anodizing and electrolytic coloring the coiled material in sequence to obtain an aluminum-based composite strip.

[0091] The anodizing and electrolytic coloring in this step can also be performed after the coil is cross-cut to form a small sheet structure.

[0092] Compared with the related art, the preparation method of the aluminum-based composite strip in this embodiment limits the constituent elements of the skin material and the constituent elements of the core material to have a different content range of at least one same element, and composite-rolls the skin material and the core material and then performs anodizing and electrolytic coloring, so that the aluminum-based composite strip can have two or more different colors through one coloring, which greatly simplifies its preparation process and reduces production costs.

[0093] In order to better reflect the specific effects brought about by the method for preparing the aluminum-based composite strip in the present invention, two specific embodiments are used as examples below. Specific embodiment 1

[0095] This embodiment provides a method for preparing an aluminum-based composite strip, which comprises the following steps:

[0096] S1. Prepare the required skin material and core material according to the requirements of aluminum alloy materials for anodizing.

[0097] Among them, the leather material includes a first leather material and a second leather material. The leather material is made of aluminum alloy with grade 5052-A. It is prepared through the steps of melting, sawing, milling and wire brush grinding to obtain a leather slab with specifications of thickness 380mm*width 890mm*length 5500mm.

[0098] The chemical composition and weight percentage of 5052-A aluminum alloy are shown in Table 1:

[0099] Table 1. Chemical composition and weight percentage of 5052-A aluminum alloy

[0100]

[0101] The test results of the melt are: slag content is 0.009mm 2 / Kg, the size of inclusions less than or equal to 3μm accounts for 95%, 4-5μm accounts for 5%, the hydrogen content is 0.10mL / 100g-A, and the coarse grain layer is 5-6mm.

[0102] The specifications of the rough ingot after melting and casting are: thickness 400mm*width 900mm*length 6000mm, the head is sawed 350mm, the tail is sawed 150mm, then the specifications of the ingot after sawing are: thickness 400mm*width 900mm*length 5500mm; one large face of the flat ingot is milled 15mm, the other large face is milled 5mm; the two opposite sides of the flat ingot are milled 5mm respectively. Then the specifications of the net ingot after milling are: thickness 380mm*width 890mm*length 5500mm.

[0103] The appearance dimension inspection of the flat ingot after milling: the thickness tolerance is 1mm, the large surface curvature is 1mm, the side curvature is 1mm, and the end curvature is 1mm.

[0104] The core material is made of aluminum alloy with the grade of 5052-B, which is prepared through the steps of melting, sawing, milling and wire brush grinding to obtain a core material blank with the specification of thickness 600mm*width 890mm*length 5500mm.

[0105] The chemical composition and weight percentage of 5052-B aluminum alloy are shown in Table 2:

[0106] Table 2. Chemical composition and weight percentage of 5052-B aluminum alloy

[0107]

[0108] The test results of the melt are: slag content is 0.010mm 2 / Kg, the size of inclusions less than or equal to 3μm accounts for 93%, 4-5μm accounts for 7%, the hydrogen content is 0.09mL / 100g-A, and the coarse grain layer is 6-7mm.

[0109] The specifications of the rough ingot after melting and casting are: thickness 630mm*width 900mm*length 6000mm, the head is sawed 350mm, the tail is sawed 150mm, then the specifications of the ingot after sawing are: thickness 630mm*width 900mm*length 5500mm; the two large faces of the flat ingot are milled 15mm respectively, and the two opposite sides of the flat ingot are milled 5mm respectively. Then the specifications of the net ingot after milling are: thickness 600mm*width 890mm*length 5500mm.

[0110] The appearance dimension inspection of the flat ingot after milling: the thickness tolerance is 1.5mm, the large surface curvature is 1mm, the side curvature is 1mm, and the end curvature is 1.3mm.

[0111] S2. After the first skin material, core material and second skin material are cooled to room temperature, they are neatly stacked in sequence. It should be noted that the large surface of the skin material with a milling length of 15 mm needs to be fixed in contact with the core material, and the other large surface of the skin material with a milling length of 5 mm faces outwards. Then the gaps at the head, middle and tail on both sides between the skin material and the core material are spot welded and fixed. The length of the spot welding is 30-40 mm to obtain a composite ingot. At this time, the specifications of the composite ingot are: thickness 1360 mm* width 890 mm* length 5500 mm.

[0112] S3. After the composite ingot is heated to a metal temperature of 495°C and a holding time of 2h, it is taken out of the furnace, the hot rolling mill emulsion spray is turned off, and the composite ingot is transported to the gap between the working rolls. When 1 / 2 of the length of the composite ingot reaches the gap between the working rolls, the movement of the composite ingot is stopped, and the upper and lower working rolls are pressed down for static pressing. When the static rolling force reaches 140T, the working rolls are rotated to start compounding at both ends without going out of the gap, and then the composite ingot is rolled for 5 passes according to the requirements of the pass reduction of 1mm, 3mm, 5mm, 7mm and 9mm, respectively, to achieve metallurgical grade welding between the skin material and the core material. After the compounding is completed, the hot rolling mill emulsion spray is turned on and conventional rolling is started. After rolling to a thickness of 1224mm, the slab is sawed to obtain a composite slab with a specification of thickness 1224mm*width 890mm*length 6111mm.

[0113] S4. After the composite slab is cooled to room temperature, the two opposite sides are cut and milled off by 10 mm (starting from the lowest point of the side depression) using a milling machine. At this time, the specifications of the composite slab are thickness 1204 mm* width 890 mm* length 6111 mm.

[0114] S5, turn the composite slab 90 degrees on the turning machine, that is, put the original side flat as the large side of the composite slab, and put the original large side vertically as the side of the composite slab. The specifications of the composite slab at this time are thickness 890mm*width 1204mm*length 6111mm.

[0115] S6. The composite slab is sent into a heating furnace, and after being heated at a metal temperature of 490°C and a holding time of 2h, it is taken out of the furnace, and hot rolled according to the process of anodized aluminum alloy strips, with a final rolling temperature of 348°C, to finally obtain a hot-rolled strip with a thickness of 5.0mm and a width of 1164mm.

[0116] S7. The hot-rolled strip is processed according to the process route of "cold rough rolling to 1.25 mm → cleaning → nitrogen protection intermediate annealing → cold finishing rolling to 1.0 mm → cleaning → nitrogen protection finished product annealing → trimming by a bending and straightening machine (trimming amount is 10 mm on each side), cleaning and straightening" and the process parameters and quality requirements of anodized aluminum alloy strips to obtain a finished cold-rolled strip with a thickness of 1.0 mm and a width of 1144 mm.

[0117] S8. The cold-rolled strip is slid and cut longitudinally to obtain a cold-rolled strip with a thickness of 1.0 mm and a width of 258 mm, i.e., the following coils. The width of the skin material is 129 mm and the width of the core material is 129 mm. This width can be further cut into 15.6 inches, i.e., a cold-rolled strip with a thickness of 1.0 mm, a width of 238 mm, and a length of 366 mm, for use in notebook computer panels.

[0118] S9, anodizing and electrolytic coloring the coil at one time, or first cross-cutting the coil to form a small sheet structure and then anodizing and electrolytic coloring, so as to obtain an aluminum-based composite strip with two different colors, such as Figure 8 shown. Specific embodiment 2

[0120] This embodiment provides a method for preparing an aluminum-based composite strip, which comprises the following steps:

[0121] S1. Prepare the required skin material and core material according to the requirements of aluminum alloy materials for anodizing.

[0122] Among them, the leather material includes the first leather material and the second leather material. The leather material is made of 1070 aluminum alloy, which is prepared through the steps of melting, sawing, milling, heating, hot rolling, cut-to-length sawing and wire brush grinding to obtain a leather slab with a specification of thickness 380mm*width 990mm*length 5789mm.

[0123] The chemical composition and weight percentage of 1070 aluminum alloy are shown in Table 3:

[0124] Table 3. Chemical composition and weight percentage of 1070 aluminum alloy

[0125]

[0126] The test results of the melt are: slag content is 0.008mm 2 / Kg, the size of inclusions less than or equal to 3μm accounts for 98%, 4-5μm accounts for 2%, the hydrogen content is 0.095mL / 100g-A, and the coarse grain layer is 5-6mm.

[0127] The specifications of the rough ingot after melting and casting are: thickness 420mm*width 1000mm*length 6000mm, the head is sawed 350mm, the tail is sawed 150mm, then the specifications of the ingot after sawing are: thickness 420mm*width 1000mm*length 5500mm; one large face of the flat ingot is milled 15mm, the other large face is milled 5mm; the two opposite sides of the flat ingot are milled 5mm respectively. Then the specifications of the net ingot after milling are: thickness 400mm*width 990mm*length 5500mm, and the specifications after hot rolling are: thickness 380mm*width 990mm*length 5789mm.

[0128] The appearance dimension inspection of the flat ingot after milling: the thickness tolerance is 1.2mm, the large surface curvature is 1.4mm, the side curvature is 1.9mm, and the end curvature is 1.1mm.

[0129] The core material is made of aluminum alloy with grade 5052, which is prepared through the steps of melting, sawing, milling, heating, hot rolling, cut-to-length sawing and wire brush grinding to obtain a core material slab with specifications of thickness 570mm*width 990mm*length 5789mm.

[0130] The chemical composition and weight percentage of 5052 aluminum alloy are shown in Table 4:

[0131] Table 2. Chemical composition and weight percentage of 5052 aluminum alloy

[0132]

[0133] The test results of the melt are: slag content is 0.011mm 2 / Kg, the size of inclusions less than or equal to 3μm accounts for 92%, 4-5μm accounts for 8%, the hydrogen content is 0.01mL / 100g-A, and the coarse grain layer is 6-7mm.

[0134] The specifications of the rough ingot after melting and casting are: thickness 630mm*width 1000mm*length 6000mm, the head is sawed 350mm, the tail is sawed 150mm, then the specifications of the ingot after sawing are: thickness 630mm*width 1000mm*length 5500mm; the two large faces of the flat ingot are milled 15mm respectively, and the two opposite sides of the flat ingot are milled 5mm respectively. Then the specifications of the net ingot after milling are: thickness 600mm*width 990mm*length 5500mm, and the specifications after hot rolling are: thickness 570mm*width 990mm*length 5789mm.

[0135] The appearance dimension inspection of the flat ingot after milling: the thickness tolerance is 1.8mm, the large surface curvature is 1.2mm, the side curvature is 1.1mm, and the end curvature is 1.7mm.

[0136] S2. After the first skin material, core material and second skin material are cooled to room temperature, they are neatly stacked in sequence. It should be noted that the large surface of the skin material with a milling length of 15 mm needs to be fixed in contact with the core material, and the other large surface of the skin material with a milling length of 5 mm faces outwards. Then the gaps at the head, middle and tail on both sides between the skin material and the core material are spot welded and fixed. The length of the spot welding is 30-40 mm to obtain a composite ingot. At this time, the specifications of the composite ingot are: thickness 1330 mm* width 990 mm* length 5789 mm.

[0137] S3. After the composite ingot is heated to a metal temperature of 492°C and a holding time of 2h, it is taken out of the furnace, the hot rolling mill emulsion spray is turned off, and the composite ingot is transported to the gap between the working rolls. When 1 / 2 of the length of the composite ingot reaches the gap between the working rolls, the movement of the composite ingot is stopped, and the upper and lower working rolls are pressed down for static pressing. When the static rolling force reaches 135T, the working rolls are rotated to start compounding at both ends without going out of the gap, and then the composite ingot is rolled for 5 passes according to the requirements of the pass reduction of 1mm, 3mm, 5mm, 7mm and 9mm, respectively, to achieve metallurgical grade welding between the skin material and the core material. After the compounding is completed, the hot rolling mill emulsion spray is turned on and conventional rolling is started. After rolling to a thickness of 1197mm, the slab is sawed to obtain a composite slab with a specification of thickness 1197mm*width 990mm*length 6433mm.

[0138] S4. After the composite slab is cooled to room temperature, the two opposite sides are cut and milled off by 10 mm (starting from the lowest point of the side depression) using a milling machine. At this time, the specifications of the composite slab are thickness 1177 mm* width 990 mm* length 6433 mm.

[0139] S5, turn the composite slab 90 degrees on the turning machine, that is, put the original side flat as the large side of the composite slab, and put the original large side vertically as the side of the composite slab. The specifications of the composite slab at this time are thickness 990mm*width 1177mm*length 6433mm.

[0140] S6. The composite slab is sent into a heating furnace, and after being heated to a metal temperature of 499° C. and a holding time of 2 h, it is taken out of the furnace, and hot rolled according to the process of anodized aluminum alloy strips, with a final rolling temperature of 346° C., and finally a hot-rolled strip with a thickness of 5.0 mm and a width of 1137 mm is obtained.

[0141] S7. The hot-rolled strip is processed according to the process route of "cold rough rolling to 1.25 mm → cleaning → nitrogen protection intermediate annealing → cold finishing rolling to 1.0 mm → cleaning → nitrogen protection finished product annealing → trimming by a bending and straightening machine (trimming amount is 10 mm on each side), cleaning and straightening" and the process parameters and quality requirements of anodized aluminum alloy strips to obtain a finished cold-rolled strip with a thickness of 1.0 mm and a width of 1117 mm.

[0142] S8. The cold-rolled strip is cut longitudinally and slit longitudinally, with the trimming amount of 10mm on each side, and no strip is drawn in the middle, to obtain a cold-rolled strip with a thickness of 1.0mm and a width of 548mm, i.e. the following coil. In this width, the width of the skin material is 292mm and the width of the core material is 256mm. This width can be further cut into 3C electronic product panels required by customers.

[0143] S9, anodizing and electrolytic coloring the coil at one time, or first cross-cutting the coil to form a small sheet structure and then anodizing and electrolytic coloring, so as to obtain an aluminum-based composite strip with two different colors, such as Fig. 9 shown.

[0144] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing an aluminum-based composite strip, characterized in that: The method for preparing the aluminum-based composite strip comprises the following steps: Step S1, preparing a skin material and a core material respectively; wherein the skin material comprises a first skin material and a second skin material, and the constituent elements of the skin material and the constituent elements of the core material have at least one same element with a different content range; Step S2, stacking and fixing the first skin material, the core material and the second skin material in order to obtain a composite ingot; Step S3, sequentially performing a first heating and composite rolling on the composite ingot to obtain a composite slab; wherein the temperature of the composite ingot is maintained at 490-500° C. during heating; Step S4, cutting off two opposite sides of the composite slab; wherein the cutting is calculated starting from the lowest point of the concave part of the side of the composite slab, and each side of the composite slab is cut off by 10-12 mm; Step S5, turning the cut composite slab by 90°; Step S6, heating and hot rolling the flipped composite slab for the second time in sequence to obtain a hot-rolled strip with a thickness of 5.0-8.0 mm; wherein the temperature of the composite slab during the second heating is 490-500° C., and the final rolling temperature of the hot rolling is 345±5° C.; Step S7, sequentially performing cold rough rolling, first cleaning, intermediate annealing under nitrogen protection, cold finishing rolling, second cleaning, finished annealing under nitrogen protection, trimming, third cleaning and straightening on the hot-rolled strip to obtain a cold-rolled strip with a thickness of 0.5-3.0 mm; Step S8, longitudinally cutting the cold-rolled strip to obtain a coil; wherein the coil at least includes a width of the skin material and a portion of the width of the core material; Step S9, anodizing and electrolytic coloring the coiled material in sequence to obtain an aluminum-based composite strip.

2. The method for preparing the aluminum-based composite strip according to claim 1, characterized in that: In the step S1, the core material is an aluminum alloy of one of the grades of 1 series, 3 series, 5 series, 6 series and 7 series aluminum alloys; the skin material and the core material are aluminum alloys of different series or aluminum alloys of the same series but different grades.

3. The method for preparing the aluminum-based composite strip according to claim 1, characterized in that: In the step S1, the leather material is prepared by melting, sawing, milling and wire brushing in sequence; or, the leather material is prepared by melting, sawing, milling, heating, hot rolling, cut-to-length sawing and slab wire brushing in sequence; The core material is prepared by melt casting, sawing, milling and wire brush grinding in sequence; or, the core material is prepared by melt casting, sawing, milling, heating, hot rolling, cut-to-length sawing and slab wire brush grinding in sequence.

4. The method for preparing the aluminum-based composite strip according to claim 3, characterized in that: The flat ingots obtained from the skin material and the core material in the melting and casting step both meet the following conditions: Slag content less than or equal to 0.012mm 2 / Kg, the size of inclusions is less than or equal to 5μm, the hydrogen content is less than or equal to 0.12mL / 100g-Al, the coarse grain layer is less than or equal to 8mm, and the composition is uniform.

5. The method for preparing the aluminum-based composite strip according to claim 3, characterized in that: After the skin material and the core material are obtained as flat ingots in the melting and casting step, the head of the flat ingot is cut off by 350-360mm, and the tail is cut off by 150-160mm; the large surface of the flat ingot obtained by the skin material in the melting and casting step close to the core material is milled by 15-20mm, and the large surface away from the core material is milled by 5-7mm; the large surface of the flat ingot obtained by the core material in the melting and casting step close to the first skin material and the large surface close to the second skin material are milled by 15-20mm respectively; the two opposite side surfaces of the flat ingot obtained by the skin material in the melting and casting step and the two opposite side surfaces of the flat ingot obtained by the core material in the melting and casting step are milled by 5-7mm respectively.

6. The method for preparing the aluminum-based composite strip according to claim 5, characterized in that: The skin material and the core material satisfy the following conditions after milling of the flat ingot obtained in the melting and casting step: The thickness tolerance is less than or equal to 2mm, the large surface curvature is less than or equal to 2mm, the side curvature is less than or equal to 2mm, and the end curvature is less than or equal to 2mm.

7. The method for preparing the aluminum-based composite strip according to claim 3, characterized in that: The diameter of the bristles of the wire brush used for polishing the leather material and the core material during the preparation process is 0.3-0.4 mm, and the assembly density is 100 pieces / cm 2 -120 pieces / cm 2 , and the grinding process is equipped with an air pipe with compressed air. After grinding, a magnetic rod with a magnetic force greater than or equal to 12000GS is used to remove magnetic materials, and then a towel dipped in D30 cleaning agent is used to wipe and remove foreign matter.

8. The method for preparing the aluminum-based composite strip according to claim 1, characterized in that: In step S3, the composite rolling preparation method comprises the following steps: Step S31, hot rolling and laminating the heated composite ingot; wherein the hot rolling and laminating is performed by a hot rolling mill, and the emulsion spraying of the hot rolling mill is turned off before the hot rolling and laminating; Step S32, transporting the composite ingot to between the working rolls of the hot rolling mill until half of the length of the composite ingot is transported to between the working rolls of the hot rolling mill, stopping the transport of the composite ingot and shutting down the hot rolling mill; Step S33, adjusting the working rolls of the hot rolling mill to statically press the composite ingot; wherein the static rolling force is 120-200T; Step S34, starting the hot rolling mill to perform composite rolling on the composite ingot without separating both ends from the working rolls, to obtain the composite slab; wherein the composite rolling includes five passes, and the reduction amounts of the five passes are 1mm, 3mm, 5mm, 7mm and 9mm respectively. Step S35, after the composite rolling is completed, the emulsion spraying of the hot rolling mill is started and rolling is performed again until the composite slab is obtained.

9. The method for preparing the aluminum-based composite strip according to claim 8, characterized in that: The maximum opening of the upper working roll and the lower working roll in the hot rolling mill is 1700 mm; in the step S4, the equipment used for cutting is a precision saw installed on the roller table of the hot rolling mill, and the maximum opening of the precision saw is 1700 mm.

10. The method for preparing the aluminum-based composite strip according to claim 1, characterized in that: In step S3, the thickness of the core material is defined as H0, the thickness of the skin material is defined as H1, the thickness of the composite slab is defined as H3, and the thickness of the composite slab satisfies the following formula: H3 / (2H1+H0)≥0.9.

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