Method for manufacturing composite metal shell

Abstract

The present application discloses a method for manufacturing a composite metal shell, comprising the following steps: providing a metal substrate; stamping the metal substrate to form a shell outer frame, the shell outer frame having a bonding surface; performing mechanical surface treatment and chemical microporous etching on the bonding surface; and die-casting an inner frame metal on the bonding surface to obtain the composite metal shell. The present application stamps a metal substrate to form a shell outer frame having a three-dimensional shape, the shell outer frame having a bonding surface, and performs mechanical surface treatment and chemical microporous etching on the bonding surface to reduce the thickness of the shell outer frame and increase the bonding force between the bonding surface and the inner frame metal, so that the prepared composite metal shell has good tensile strength and shear strength at the bonding surface between the shell outer frame and the inner frame metal.

Description

Technical Field

[0001] The present application relates to the field of composite metal materials, and in particular to a method for manufacturing a composite metal shell. Background Art

[0002] In the prior art, two metal materials are pressed together by hot pressing and rolling to prepare a composite metal material. However, this method can only produce composite materials with a planar bonding surface, and cannot produce composite materials with a three-dimensional and complex bonding surface. Summary of the invention

[0003] In view of this, the present application provides a method for manufacturing a composite metal shell that can solve the above technical problems.

[0004] A method for manufacturing a composite metal shell, comprising: Providing a metal substrate; Punching the metal substrate to form a shell outer frame, wherein the shell outer frame has a bonding surface; Performing mechanical surface treatment and chemical micropore etching on the bonding surface; The inner frame metal is die-casted on the joint surface to obtain the composite metal shell.

[0005] In some embodiments, the metal substrate is made of titanium alloy, and the inner frame metal is made of aluminum.

[0006] In some embodiments, the thickness of the metal substrate is 1.95 mm to 2.05 mm, the stamping temperature is 910° C. to 950° C., the stamping pressure is 155 Torr to 165 Torr, and the stamping time is 9.5 min to 10.5 min.

[0007] In some embodiments, the shell frame includes a back plate, two oppositely disposed first side plates, and two oppositely disposed second side plates, and the two first side plates and the two second side plates surround one side of the back plate to form a groove.

[0008] In some embodiments, before the bonding surface is subjected to mechanical surface treatment and chemical micropore etching, it also includes: using a de-hardening layer reagent to remove the hardened layer on one side of the bonding surface of the shell outer frame, the composition of the de-hardening layer reagent includes nitric acid and sulfuric acid, and the pH of the de-hardening layer reagent is less than 2.

[0009] In some embodiments, the chemical micropore etching comprises: Placing the outer frame of the shell in a sodium hydroxide solution for degreasing; The outer frame of the shell is placed in a corrosive solution for corrosion, wherein the temperature of the corrosive solution is 45° C. to 65° C., the corrosion voltage is 10V to 95V, and the corrosion time is 30s to 600s.

[0010] In some embodiments, the die-casting temperature is 640° C. to 660° C., and the die-casting pressure is 460 MPa to 470 MPa.

[0011] In some embodiments, the micropore density of the chemical micropore etching is 31% to 40%, the average micropore depth is 35 μm to 50 μm, and the average micropore diameter is 48 μm to 65 μm.

[0012] In some embodiments, the step of mechanical surface treatment comprises: The first side panel includes a first outer side surface and a first inner side surface that are opposite to each other. The first side panel is thinned by 0.30 mm to 0.50 mm along a direction from the first outer side surface to the first inner side surface. The second side panel includes a second outer side surface and a second inner side surface that are opposite to each other. The second side panel is thinned by 0.30 mm to 0.50 mm along a direction from the second outer side surface to the second inner side surface. The first side panel and the second side panel are thinned by 0.39 mm to 0.49 mm in a direction toward the back panel. The back panel is thinned by 0.10 mm to 0.20 mm in a direction away from the first side panel and the second side panel.

[0013] In some embodiments, the composite metal shell includes the shell outer frame and the inner frame metal, the shell outer frame is provided with the groove, the inner frame metal is accommodated in the groove, and the shell outer frame and the inner frame metal are joined via the joining surface.

[0014] The present application punches a metal substrate to form a shell outer frame with a three-dimensional shape, and the shell outer frame has a bonding surface. The bonding surface is subjected to mechanical surface treatment and chemical microporous etching to reduce the thickness of the shell outer frame and increase the bonding force between the bonding surface and the inner frame metal, so that the prepared composite metal shell has good tensile strength and shear strength at the bonding surface between the shell outer frame and the inner frame metal. The manufacturing method provided by the present application enables the composite metal shell to have a complex three-dimensional shape to meet various appearance requirements, and also has structural reliability, that is, the two metals can be tightly combined and not easily separated. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of a method for manufacturing a composite metal shell provided in one embodiment of the present application.

[0016] Figure 2 A schematic structural diagram of a metal substrate provided in one embodiment of the present application.

[0017] Figure 3 A schematic diagram of the structure of a shell frame provided in one embodiment of the present application.

[0018] Figure 4 A schematic structural diagram of a composite metal shell provided in one embodiment of the present application.

[0019] Main component symbols The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0020] The embodiments of the present application are described in detail below. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application. The reagents and materials described in the following embodiments can all be obtained from commercial sources.

[0021] See also Figures 1 to 4 The present application provides a method for manufacturing a composite metal shell 100, comprising: Providing a metal substrate 1; The metal substrate 1 is stamped to form a housing outer frame 10, and the housing outer frame 10 has a bonding surface 30; Performing mechanical surface treatment and chemical micropore etching on the bonding surface 30; The inner frame metal 20 is die-casted on the joint surface 30 to obtain the composite metal shell 100 .

[0022] In some embodiments, the material of the metal substrate 1 is titanium alloy, and the material of the inner frame metal 20 is aluminum. In other embodiments, the materials of the metal substrate 1 and the inner frame metal 20 may also be other metals.

[0023] In some embodiments, the thickness of the metal substrate 1 is 1.95 mm to 2.05 mm, the stamping temperature is 910° C. to 950° C., the stamping pressure is 155 Torr to 165 Torr, and the stamping time is 9.5 min to 10.5 min.

[0024] For example, the thickness of the metal substrate 1 can be 1.95 mm, 2.00 mm, 2.05 mm, or any value within the range formed by any two of the above values; the stamping temperature can be 910°C, 920°C, 930°C, 940°C, 950°C, or any value within the range formed by any two of the above values; the stamping pressure can be 155 Torr, 158 Torr, 160 Torr, 162 Torr, 165 Torr, or any value within the range formed by any two of the above values; the stamping time can be 9.5 min, 9.8 min, 10 min, 10.2 min, 10.5 min, or any value within the range formed by any two of the above values. The stamping temperature, pressure, and time match the thickness of the metal substrate 1, so that the stamping temperature, pressure, and time are within the above range, the metal substrate 1 within the above thickness range can be stamped into a three-dimensional shape, and the stamped housing frame 10 has sufficient hardness.

[0025] In some embodiments, see Figure 3 The shell frame 10 includes a back plate 11, two oppositely disposed first side plates 12 and two oppositely disposed second side plates 13. The two first side plates 12 and the two second side plates 13 surround one side of the back plate 11 to form a groove 14.

[0026] In some embodiments, before the mechanical surface treatment and chemical micropore etching are performed on the bonding surface 30, the process further includes: removing the hardened layer with a hardened layer removal reagent, wherein the hardened layer removal reagent comprises nitric acid and sulfuric acid, wherein the proportion of nitric acid and sulfuric acid in the hardened layer removal reagent is 35wt% to 45wt%, and the pH of the hardened layer removal reagent is less than 2. By using a hardened layer removal reagent having a strong acidity to treat the bonding surface 30, the hardened layer such as the oxide layer at the bonding surface 30 can be effectively removed, thereby facilitating the subsequent chemical micropore etching step.

[0027] In some embodiments, the step of mechanical surface treatment includes: the first side panel 12 includes a first outer side surface 121 and a first inner side surface 122 relative to each other, and the first side panel 12 is thinned by 0.30 mm to 0.50 mm in a direction from the first outer side surface 121 to the first inner side surface 122; the second side panel 13 includes a second outer side surface 131 and a second inner side surface 132 relative to each other, and the second side panel 13 is thinned by 0.30 mm to 0.50 mm in a direction from the second outer side surface 131 to the second inner side surface 132; the first side panel 12 and the second side panel 13 are thinned by 0.39 mm to 0.49 mm in a direction toward the back panel 11; and the back panel 11 is thinned by 0.10 mm to 0.20 mm in a direction away from the first side panel 12 and the second side panel 13.

[0028] For example, the first side plate 12 can be thinned by 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm or any value within the range formed by any two of the above values ​​in the direction from the first outer side surface 121 to the first inner side surface 122; the second side plate 13 can be thinned by 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm or any value within the range formed by any two of the above values ​​in the direction from the second outer side surface 131 to the second inner side surface 132; the first side plate 12 and the second side plate 13 can be thinned by 0.39 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.49 mm or any value within the range formed by any two of the above values ​​in the direction toward the back plate 11; the back plate 11 can be thinned by 0.10 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm in the direction away from the first side plate 12 and the second side plate 13 mm, 0.20 mm or any value within the range formed by any two of the above values. Reasonably controlling the thinning thickness of the first side plate 12, the second side plate 13 and the back plate 11 within the above range can not only make the shell frame 10 thinner and fully remove the oxide layer on the surface that will affect the bonding strength of the bonding surface 30, but also ensure that the bonding surface 30 is intact without destroying the structure of the bonding surface 30.

[0029] In some embodiments, the step of chemical microporous etching includes: placing the outer frame 10 of the housing in a sodium hydroxide solution for degreasing; placing the outer frame 10 of the housing in a corrosive solution for etching. In this embodiment, a direct current electrochemical etching technique can be used to perform microporous etching on the bonding surface 30. The corrosive solution can be a perchloric acid solution with a concentration of 1% to 51%. The temperature of the corrosive solution is 45°C to 65°C, the corrosion voltage is 10V to 95V, and the corrosion time is 30s to 600s. In other embodiments, the corrosive solution can also be a solution including nitric acid, chromic acid or hypochlorous acid.

[0030] For example, the temperature of the etching liquid can be 45°C, 50°C, 55°C, 60°C, 65°C, or any value within the range formed by any two of the above values; the etching voltage can be 10V, 20V, 30V, 40V, 50V, 60V, 70V, 80V, 90V, 95V, or any value within the range formed by any two of the above values; the etching time can be 30s, 50s, 100s, 200s, 300s, 400s, 500s, 600s, or any value within the range formed by any two of the above values. The temperature of the etching liquid, the etching voltage, and the etching time are within the above ranges, which is conducive to etching the bonding surface 30 into micropores with a suitable number, suitable density, suitable depth, and suitable diameter, so as to increase the bonding force between the bonding surface 30 and the inner frame metal 20.

[0031] In some embodiments, the micropore density of chemical micropore etching is 31% to 40%, the average micropore depth is 35 μm to 50 μm, and the average micropore diameter may be 48 μm to 65 μm.

[0032] For example, the micropore density of chemical micropore etching can be 32%, 33%, 34%, 35% or any value within the range formed by any two of the above values, the average micropore depth can be 35μm, 36μm, 37μm, 38μm, 39μm, 40μm or any value within the range formed by any two of the above values, and the average micropore diameter can be 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm or any value within the range formed by any two of the above values. Appropriate micropore density, average micropore depth and average micropore diameter can enhance the good bonding force between the bonding surface 30 and the subsequent inner frame metal 20, so that the outer frame 10 of the shell and the inner frame metal 20 have good tensile strength and shear strength at the bonding surface 30.

[0033] In some embodiments, the die-casting temperature is 640°C to 660°C, and the die-casting pressure is 460Mpa to 470Mpa. For example, the die-casting temperature can be 640°C, 645°C, 650°C, 655°C, 660°C, or any value within the range formed by any two of the above values, and the die-casting pressure can be 460Mpa, 462Mpa, 464Mpa, 466Mpa, 468Mpa, 470Mpa, or any value within the range formed by any two of the above values. The die-casting temperature and pressure within the above range are conducive to improving the bonding strength between the outer frame 10 of the housing and the inner frame metal 20.

[0034] In some embodiments, see Figure 4 The composite metal shell 100 includes a shell outer frame 10 and an inner frame metal 20 . The shell outer frame 10 is provided with a groove 14 . The inner frame metal 20 is accommodated in the groove 14 . The shell outer frame 10 and the inner frame metal 20 are joined via a bonding surface 30 .

[0035] The present application is described in detail below through specific embodiments.

[0036] Example 1 S1: Please refer to Figure 2 A metal substrate 1 is provided. The material composition of the metal substrate 1 is Ti-6Al-4V. The length of the metal substrate 1 is 173 mm, the width is 89.1 mm, and the thickness is 2.0 mm.

[0037] S2: Use a precision punching machine of model SN1-160 to punch the metal substrate 1 to form the following Figure 3The shell frame 10 shown has a bonding surface 30. Specifically, the precision punch press is first heated to 300°C for preheating, and then heated to 930°C to stamp the metal substrate 1. The stamping time is 10 minutes and the stamping pressure is 160 Torr. The shell frame 10 includes a back plate 11, two first side plates 12 arranged opposite to each other along a first direction X, and two second side plates 13 arranged opposite to each other along a second direction Y. The two first side plates 12 and the two second side plates 13 surround one side of the back plate 11 to form a groove 14.

[0038] S3: Degrease and wash the outer shell frame 10, prepare a de-hardening agent using nitric acid and sulfuric acid, the proportion of nitric acid and sulfuric acid in the de-hardening agent is 40wt%, and the pH of the de-hardening agent is adjusted to 1.5. Then immerse the outer shell frame 10 in the de-hardening agent for 0.75h to remove the oxide layer on the bonding surface 30 and other substances that will affect its bonding strength, and then take it out and wash it with water and dry it.

[0039] S4: Please refer to Figure 3 The shell frame 10 is thinned using a CNC machine tool, the first side plate 12 is thinned by 0.40 mm along the first direction X, the second side plate 13 is thinned by 0.40 mm along the second direction Y, the first side plate 12 and the second side plate 13 are thinned by 0.44 mm along a third direction Z perpendicular to the first direction X and the second direction Y, and the back plate 11 is thinned by 0.15 mm along the third direction Z.

[0040] S5: Place the outer shell frame 10 in a sodium hydroxide solution with a temperature of 55°C and a concentration of 55g / L for degreasing for 4 minutes, and then wash it in deionized water for 30 seconds. Then place the outer shell frame 10 in a corrosive solution (the components of the corrosive solution are perchloric acid, water and ethanol, wherein the volume ratio of perchloric acid, water and ethanol is 2:4:4) for surface chemical micropore etching, wherein the temperature of the corrosive solution is 55°C, the corrosion voltage is 50V, and the corrosion time is 200 seconds. After the chemical micropore etching is completed, the outer shell frame 10 is fully washed with water to remove the corrosion liquid residue on its surface, and then dried.

[0041] S6: Please refer to Figure 4 Liquid aluminum is die-casted on the joint surface 30, and after the liquid aluminum is cooled and solidified, the inner frame metal 20 is formed on the joint surface 30 to obtain the composite metal shell 100. The die-casting temperature is 650°C and the die-casting pressure is 465Mpa.

[0042] The differences between Examples 2 to 6 and the example are shown in Table 1, and the other conditions are the same as those of Example 1.

[0043] Table 1 <Performance Test> Pore ​​density, pore depth, and pore diameter: Detected using Keyence instruments.

[0044] Appearance: Observe whether the outer frame of the shell has a three-dimensional structure.

[0045] Tensile strength: The tensile strength of the bonding surface is tested using the universal dynamic tensile method.

[0046] Shear strength: The shear strength of the joint surface is tested using the Shear transverse shear method. The above performance tests were performed on Examples 1 to 6, and the test results are shown in Table 2.

[0047] Table 2 It can be seen from Table 1 and Table 2 that the composite metal shell produced according to the method provided in the present application can have a three-dimensional shape, and the outer frame and inner frame metal of the shell have good tensile strength and shear strength.

[0048] By comparing Example 1 with Examples 4 and 5, it can be seen that suitable corrosion conditions, including the temperature of the corrosion solution, the corrosion voltage and the corrosion time, are conducive to chemical micropore etching, and suitable micropore density, average micropore depth and average micropore diameter can be etched out, thereby improving the tensile strength and shear strength between the outer frame and the inner frame metal of the shell. The temperature, voltage and time of chemical micropore etching in Example 5 are higher than the upper limit, and the micropore density, average micropore depth and average micropore diameter obtained by etching will also be relatively too high, and the metal component of the outer frame of the shell will be reduced due to excessive corrosion, thereby weakening the tensile strength and shear strength of the composite metal shell.

[0049] By comparing Example 1 with Example 6, it can be seen that suitable die-casting temperature and die-casting pressure are conducive to improving the bonding force between the outer frame of the shell and the inner frame metal, that is, improving the tensile strength and shear strength between the outer frame of the shell and the inner frame metal.

[0050] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application is described in detail with reference to the above implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for manufacturing a composite metal shell, characterized in that: include: Providing a metal substrate; Punching the metal substrate to form a shell outer frame, wherein the shell outer frame has a bonding surface; Performing mechanical surface treatment and chemical micropore etching on the bonding surface; The inner frame metal is die-casted on the joint surface to obtain the composite metal shell.

2. The method for manufacturing a composite metal shell according to claim 1, characterized in that: The material of the metal substrate is titanium alloy, and the material of the inner frame metal is aluminum.

3. The method for manufacturing a composite metal shell according to claim 1, wherein: The thickness of the metal substrate is 1.95 mm to 2.05 mm, the stamping temperature is 910° C. to 950° C., the stamping pressure is 155 Torr to 165 Torr, and the stamping time is 9.5 min to 10.5 min.

4. The method for manufacturing a composite metal shell according to claim 1, characterized in that: The shell outer frame includes a back plate, two first side plates arranged opposite to each other, and two second side plates arranged opposite to each other. The two first side plates and the two second side plates surround one side of the back plate to form a groove.

5. The method for manufacturing a composite metal shell according to claim 1, characterized in that: Before the bonding surface is subjected to mechanical surface treatment and chemical micropore etching, the method further includes: removing the hardened layer on one side of the bonding surface of the shell outer frame with a hardening layer removal reagent, wherein the composition of the hardening layer removal reagent includes nitric acid and sulfuric acid, and the pH of the hardening layer removal reagent is less than 2.

6. The method for manufacturing a composite metal shell according to claim 1, characterized in that: The chemical micropore etching comprises: Placing the outer frame of the shell in a sodium hydroxide solution for degreasing; The outer frame of the shell is placed in a corrosive solution for corrosion, wherein the temperature of the corrosive solution is 45° C. to 65° C., the corrosion voltage is 10V to 95V, and the corrosion time is 30s to 600s.

7. The method for manufacturing a composite metal shell according to claim 1, characterized in that: The temperature of the die-casting is 640° C. to 660° C., and the pressure of the die-casting is 460 MPa to 470 MPa.

8. The method for manufacturing a composite metal shell according to claim 1, wherein: The micropore density of the chemical micropore etching is 31% to 40%, the average micropore depth is 35 μm to 50 μm, and the average micropore diameter is 48 μm to 65 μm.

9. The method for manufacturing a composite metal shell according to claim 4, characterized in that: The mechanical surface treatment steps include: The first side panel includes a first outer side surface and a first inner side surface that are opposite to each other. The first side panel is thinned by 0.30 mm to 0.50 mm along a direction from the first outer side surface to the first inner side surface. The second side panel includes a second outer side surface and a second inner side surface that are opposite to each other. The second side panel is thinned by 0.30 mm to 0.50 mm along a direction from the second outer side surface to the second inner side surface. The first side panel and the second side panel are thinned by 0.39 mm to 0.49 mm in a direction toward the back panel. The back panel is thinned by 0.10 mm to 0.20 mm in a direction away from the first side panel and the second side panel.

10. The method for manufacturing a composite metal shell according to claim 4, characterized in that: The composite metal shell comprises the shell outer frame and the inner frame metal, the shell outer frame is provided with the groove, the inner frame metal is accommodated in the groove, and the shell outer frame and the inner frame metal are joined via the joining surface.

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