Composite metal shell and manufacturing method thereof

Abstract

The invention discloses a composite metal shell and a manufacturing method thereof. The manufacturing method of the composite metal shell comprises the following steps: providing a first metal base material; the first metal base material is subjected to hot forging machining to form a metal inner shell, the metal inner shell comprises a main body and a boss, and the boss protrudes from the main body; performing chemical micropore etching on the metal inner shell; a shell metal layer comprising second metal is formed on the side, provided with the boss, of the main body through die casting, and the boss is embedded in the shell metal layer; a groove is formed in the side, away from the boss, of the main body, and the groove penetrates through the main body and extends into the boss. In the composite metal shell provided by the invention, the groove can avoid the junction of the metal inner shell and the metal layer of the outer shell, so that a chemical film with uniform thickness can be formed on the inner wall of the groove in a chemical process, the composite metal shell can be effectively protected, and the probability of corrosion at the groove is reduced.

Description

Technical Field

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

[0002] In the traditional scheme, the titanium-aluminum composite material includes a stacked titanium layer and an aluminum layer, and the junction of the titanium layer and the aluminum layer is a bonding line. For the chemical process of the titanium-aluminum composite material, a through hole is opened in the titanium-aluminum composite material that penetrates the titanium layer and the aluminum layer. Taking the anode process as an example, after the titanium-aluminum composite material undergoes the anode process, an anode film grows on the inner wall of the through hole. However, for the titanium-aluminum composite material, after the anode process is completed, the thickness of the anode film grown by the titanium layer and the aluminum layer is inconsistent, and usually the anode film thickness of the aluminum layer is greater than that of the titanium layer. Due to the different expansion coefficients of titanium and aluminum materials, once exposed to a high temperature environment, the bonding line will be used as a breakthrough point, and the anode film at the junction of the titanium layer and the aluminum layer will crack or break. The cracked or broken part is exposed to the outside world, making the titanium-aluminum composite material susceptible to corrosion at the through hole. Summary of the invention

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

[0004] The first aspect of the present application provides a method for manufacturing a composite metal shell, comprising: providing a first metal substrate; Performing hot forging on the first metal substrate to form a metal inner shell, wherein the metal inner shell comprises a main body and a boss, wherein the boss protrudes from the main body; Performing chemical micropore etching on the metal inner shell; An outer shell metal layer including a second metal is formed by die-casting on one side of the metal inner shell provided with the boss, and the boss is embedded in the outer shell metal layer; A groove is formed on a side of the main body away from the boss, and the groove penetrates the main body and extends into the boss.

[0005] In some embodiments, the first metal substrate comprises a titanium alloy and the second metal comprises aluminum.

[0006] In some embodiments, the step of "performing hot forging on the first metal substrate to form a metal inner shell" includes: heating the first metal substrate to 850°C~950°C, pouring it into a first mold with a temperature of 300°C~350°C, applying pressure to the first mold to shape the first metal substrate into the metal inner shell.

[0007] In some embodiments, the thickness of the main body is 5.4 mm~5.7 mm, the height of the boss is greater than 0 and less than 5.0 mm, the width of the boss is greater than 1.0 mm, the top R angle of the boss is greater than 0.5 mm, and the bottom R angle of the boss connected to the main body is greater than 0.5 mm.

[0008] In some embodiments, the micropores obtained by the chemical micropore etching are in the shape of a water droplet-shaped structure.

[0009] In some embodiments, the pore diameter of the micropores is 60 μm to 160 μm, the pore depth of the micropores is 50 μm to 130 μm, and the pore density of the micropores is 50% to 80%.

[0010] In some embodiments, the step of "forming an outer shell metal layer including a second metal by die-casting on a side of the metal inner shell provided with the boss" includes: heating the second metal to 660°C~690°C, pouring it into a second mold with a temperature of 260°C~300°C, and die-casting the second mold with the second metal on a side of the metal inner shell provided with the boss to form the outer shell metal layer, the die-casting speed is 0.8 m / s~1.6m / s, the die-casting pressure is 300 Mpa~500Mpa, and the die-casting time is 0.08s~0.2s.

[0011] In some embodiments, the outer shell metal layer has a bonding surface, the metal inner shell covers the bonding surface, and the distance between the groove and the bonding surface is 0.7 mm to 0.8 mm.

[0012] A second aspect of the present application provides a composite metal shell, comprising a metal inner shell and an outer metal layer, the metal inner shell comprising a main body and a boss, the boss protruding from the main body, the outer metal layer covering the boss exposed on the surface of the main body, the boss embedded in the outer metal layer, and a groove is provided on the side of the metal inner shell facing away from the boss, the groove passes through the main body and extends into the boss.

[0013] In some embodiments, the outer shell metal has a bonding surface, the metal inner shell covers the bonding surface, and the distance between the groove and the bonding surface is 0.7 mm to 0.8 mm.

[0014] The present application forms a metal inner shell by processing a first metal substrate, the metal inner shell includes a main body and a boss, the boss protrudes from the main body; chemical microporous etching is performed on the metal inner shell; a shell metal layer including a second metal is formed by die-casting on a side of the metal inner shell where the boss is provided, the boss is embedded in the shell metal layer; a groove is formed on a side of the main body away from the boss, the groove passes through the main body and extends to and at least partially into the boss. In this way, the groove can avoid the junction of the metal inner shell and the outer shell metal layer, which is conducive to forming a chemical film of uniform thickness on the inner wall of the groove during the chemical process, and the chemical film does not crack or break, which can effectively protect the composite metal shell and reduce the probability of corrosion at the groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic structural diagram of a metal substrate provided in one embodiment of the present application.

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

[0017] Figure 3 A schematic structural diagram of a composite metal shell provided in one embodiment of the present application.

[0018] Figure 4 A partial cross-sectional schematic diagram of a composite metal shell provided with a groove provided in one embodiment of the present application.

[0019] Figure 5 A partial cross-sectional schematic diagram of a metal inner shell provided in one embodiment of the present application.

[0020] Figure 6 A schematic diagram of the structure of a micropore provided in one embodiment of the present application.

[0021] Figure 7 This is a scanning electron microscope image of the metal bonding surface between the main body and the outer shell of the metal inner shell provided in one embodiment of the present application.

[0022] Main component symbols The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0023] 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.

[0024] See also Figures 1 to 5The present application provides a method for manufacturing a composite metal shell 100, comprising: Providing a first metal substrate 10; The first metal substrate 10 is hot forged to form a metal inner shell 20, wherein the metal inner shell 20 includes a main body 21 and a boss 22, wherein the boss 22 protrudes from the main body 21; Performing chemical micropore etching on the metal inner shell 20; An outer shell metal layer 30 including a second metal is formed by die casting on one side of the metal inner shell 20 provided with the boss 22, and the boss 22 is embedded in the outer shell metal layer 30; A groove 40 is formed on a side of the main body 21 away from the boss 22 . The groove 40 penetrates the main body 21 and extends into the boss 22 .

[0025] In some embodiments, the first metal substrate 10 includes a titanium alloy and the second metal includes aluminum.

[0026] In some embodiments, the step of "forming a metal inner shell 20 by hot forging the first metal substrate 10" includes: heating the first metal substrate 10 to 850°C~950°C, pouring it into a first mold with a temperature of 300°C~350°C, applying pressure to the first mold, and forming the first metal substrate 10 into the metal inner shell 20.

[0027] The hot forging process includes using a forging machine to apply pressure to the upper die and the lower die to press them together, so that the heated first metal substrate 10 is integrally formed into the desired shape and structure in the die. The hot forging method can form multiple and various shapes and structures at one time, and the shape and position size of the formed product are highly accurate and the production efficiency is high. The tonnage of the forging machine can be selected according to the size of the product.

[0028] In some embodiments, the first metal substrate 10 can be heated to 850°C, 880°C, 900°C, 920°C, 950°C, or any value within the range formed by any two of the above values; the temperature of the mold can be 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, or any value within the range formed by any two of the above values. Controlling the heating temperature of the first metal substrate 10 within the above range is conducive to the first metal substrate 10 reaching a state of plastic deformation and is conducive to its molding into a metal inner shell 20. The temperature of the mold within the above range can reduce the occurrence of the situation where the plastic deformation effect of the first metal substrate 10 is deteriorated due to a sudden drop in temperature of the heated first metal substrate 10.

[0029] In some embodiments, see Figure 5, the thickness T of the main body 21 is 5.4 mm to 5.7 mm, the height H of the boss 22 is greater than 0 and less than 5.0 mm, the width W of the boss 22 is greater than 1.0 mm, the top R angle (R1) of the boss 22 is greater than 0.5 mm, and the bottom R angle (R2) of the connection between the boss 22 and the main body 21 is greater than 0.5 mm. When the thickness T of the main body 21 is within the above range, the composite metal shell 100 can be made thinner; when the height H, width W, top R angle and bottom R angle of the boss 22 are within the above range, the occurrence of material shortage, cracks and other undesirable conditions in the formed boss 22 structure can be reduced, thereby improving the structural strength of the boss 22.

[0030] In some embodiments, the shape of the boss 22 may be cylindrical, cube, or cuboid, etc. The shape or shape of the boss 22 may be selected and designed according to actual needs.

[0031] In some embodiments, see Figure 6 , Figure 7 The micropores 50 obtained by chemical micropore etching are in the shape of a water droplet-shaped structure. After the metal inner shell 20 is die-casted with the outer shell metal layer 30, part of the outer shell metal layer 30 penetrates into the micropores 50, which can make the bonding strength between the outer shell metal layer 30 and the metal inner shell 20 higher. In this application, the "water droplet-shaped structure" means that the width of the micropores gradually increases from top to bottom.

[0032] In some embodiments, the pore size of the micropore 50 is 60 μm to 160 μm, the pore depth of the micropore 50 is 50 μm to 130 μm, and the pore density of the micropore 50 is 50% to 80%. For example, the pore size of the micropore 50 can be 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, or any value within the range formed by any two of the above values; the pore depth of the micropore 50 can be 50 μm, 70 μm, 90 μm, 110 μm, 130 μm, or any value within the range formed by any two of the above values; the pore density of the micropore 50 can be 50%, 60%, 70%, 80%, or any value within the range formed by any two of the above values. The pore diameter, pore depth and pore density of the micropores 50 are within the above ranges, which is conducive to forming a suitable number of micropores 50 with a water droplet-shaped structure, and the second metal is easy to penetrate into the micropores 50 during subsequent die casting, thereby increasing the bonding strength between the outer shell metal layer 30 and the metal inner shell 20. The present application does not specifically limit the method of chemical micropore etching, and micropores with pore diameter, pore depth and pore density within the above ranges can be obtained by conventional chemical micropore etching methods in the art.

[0033] In some embodiments, the step of "forming an outer shell metal layer 30 including a second metal by die casting on a side of the metal inner shell 20 where the boss 22 is provided" includes: heating the second metal to 660°C~690°C, pouring it into a second mold with a temperature of 260°C~300°C, and die casting the second mold with the second metal on the side of the metal inner shell 20 where the boss 22 is provided to form the outer shell metal layer 30, the die casting speed is 0.8 m / s~1.6 m / s, the die casting pressure is 300 Mpa~500 Mpa, and the die casting time is 0.08s~0.2s.

[0034] For example, the second metal can be heated to 660°C, 670°C, 680°C, 690°C, or any value within the range formed by any two of the above values; the temperature of the mold can be 260°C, 270°C, 280°C, 290°C, 300°C, or any value within the range formed by any two of the above values; the die-casting speed can be 0.8 m / s, 1.0 m / s, 1.2 m / s, 1.4 m / s, 1.6 m / s, or any value within the range formed by any two of the above values; the die-casting pressure can be 300 MPa, 350 MPa, 400 MPa, 450 MPa, 500 MPa, or any value within the range formed by any two of the above values; the die-casting time can be 0.08 s, 0.10 s, 0.12 s, 0.14 s, 0.16 s, 0.18 s, 0.2 s, or any value within the range formed by any two of the above values.

[0035] The heating temperature of the second metal is controlled within the above range, which is conducive to its molding in the mold. When the temperature of the mold is within the above range, on the one hand, it can reduce the problem of the second metal being difficult to mold due to too low temperature, and can also reduce the flow marks and cracks on the surface of the shell metal layer 30 after molding. On the other hand, it can avoid the low operability of the method caused by too high temperature. When the speed, pressure and time of die casting are within the above range, it can reduce the phenomenon of incomplete structure of the molded shell metal layer 30 due to insufficient filling in the second mold, and can also reduce the flow marks, cracks, bulges and the like on the surface of the molded shell metal layer 30, thereby reducing the defective rate.

[0036] In some embodiments, the outer shell metal layer 30 has a bonding surface 60, the metal inner shell 20 covers the bonding surface 60, and the distance d between the groove 40 and the bonding surface 60 is 0.7 mm to 0.8 mm. For example, the distance d between the groove 40 and the bonding surface 60 can be 0.7 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.8 mm, or any value within the range formed by any two of the above values. The distance d between the groove 40 and the bonding surface 60 is controlled within the above range, so that the groove 40 can avoid the junction of the metal inner shell 20 and the outer shell metal layer 30, which is conducive to forming an anode film with uniform thickness on the inner wall of the groove 40 during a chemical process, such as an anodic process, and the anode film does not crack or break, thereby effectively protecting the composite metal shell 100 and reducing the probability of corrosion at the groove 40.

[0037] In some embodiments, the groove 40 may be formed by machining, such as drilling, boring, etc.

[0038] The present application also provides a composite metal shell 100, including a metal inner shell 20 and an outer metal layer 30, the metal inner shell 20 includes a main body 21 and a boss 22, the boss 22 protrudes from the main body 21, the outer metal layer 30 covers the boss 22 and is exposed on the surface of the main body 21, the boss 22 is embedded in the outer metal layer 30, and a groove 40 is provided on the side of the metal inner shell 20 away from the boss 22, the groove 40 passes through the main body 21 and extends into the boss 22, the groove 40 includes a top 41 and a side wall 42 arranged around the top 41, part of the boss 22 is exposed at the top 41, and the main body 21 and part of the boss 22 are exposed at the side wall 42.

[0039] In some embodiments, the outer shell metal layer 30 has a bonding surface 60, the metal inner shell 20 covers the bonding surface 60, and the distance between the groove 40 and the bonding surface 60 is 0.7 mm to 0.8 mm. For example, the distance d between the groove 40 and the bonding surface 60 can be 0.7 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.8 mm, or any value within the range formed by any two of the above values. The distance d between the groove 40 and the bonding surface 60 is controlled within the above range, so that at the boss 22, the metal inner shell 20 still covers the outer shell metal layer 30, and the outer shell metal layer 30 is protected by the metal inner shell 20, which has a good anti-corrosion and waterproof effect on the bonding surface 60.

[0040] The present application is described in detail below through specific embodiments.

[0041] Example 1 S1: providing a titanium rod substrate, and heating the titanium rod substrate to 900° C.; S2: providing a first die, heating the temperature of the first die to 320°C, the first die comprising an upper die and a lower die, transferring the heated titanium rod substrate into the lower die of the first die, and then covering the surface of the lower die with the upper die, and pressing the upper die and the lower die with a forging machine, so that the titanium rod substrate is formed into a titanium metal inner shell, the titanium metal inner shell comprising a main body and a boss, the boss protruding from the main body, the thickness of the main body is 5.5 mm, the height of the boss is 3 mm, the width of the boss is 5 mm, the top R angle (R1) of the boss is 0.6 mm, and the bottom R angle (R2) of the connection between the boss and the main body is 0.6 mm; S3: chemically etching the titanium metal inner shell to produce micropores with a water droplet-shaped structure on the surface of the titanium metal inner shell, with a pore diameter of 60-110 μm, a pore depth of 70-100 μm, and a pore density of 60%; S4: Aluminum is provided as a raw material of the outer shell metal, and the aluminum is heated to 680°C, and then the aluminum is poured into a second mold with a temperature of 280°C, and the second mold is die-casted toward the titanium inner shell, the die-casting speed is 1 m / s, the die-casting pressure is 400 MPa, and the die-casting time is 0.1s. After molding, the aluminum covering boss is exposed on the surface of the titanium inner shell body, and the boss is embedded in the aluminum; S5: A groove is formed by machining on the side of the titanium metal inner shell away from the boss to obtain a composite metal shell. The groove runs through the main body and part of the boss, and the groove includes a top and a side wall arranged around the top. Part of the boss is exposed at the top of the groove, and the main body is exposed at the side wall of the groove. The aluminum material has a bonding surface, and the titanium metal inner shell covers the bonding surface. The distance between the groove and the bonding surface is 0.75 mm.

[0042] The differences between Examples 2 to 7 and Example 1 are shown in Tables 1 and 2, and the rest are the same as Example 1.

[0043] Table 1 Table 2 <Performance Test> Appearance: Observe whether the surface of the prepared composite metal shell is smooth, whether there are burrs or flow marks, and whether the structure is defective. If the surface is smooth, has no flow marks, no burrs, and the structure is complete, the appearance is rated as good; if the appearance is slightly rough, has burrs, has flow marks, or has structural defects and incompleteness, the appearance is rated as medium; if the appearance is seriously rough, has burrs, has flow marks, or has structural defects and incompleteness, the appearance is rated as poor. If the appearance grade reaches medium or good, the appearance of the composite metal shell can be judged to be qualified; if the appearance grade is poor, the appearance of the composite metal shell is judged to be unqualified.

[0044] Bonding strength: The prepared composite metal shell is placed in a universal testing machine to test the shear strength.

[0045] The composite metal shells prepared in Examples 1 to 6 were subjected to performance tests on appearance and bonding strength. The test results are shown in Table 3.

[0046] Table 3 It can be seen from Tables 1 to 3 that the composite metal shell prepared in the present application has good bonding strength between the metal inner shell and the outer shell metal, and the appearance can reach medium or good.

[0047] By comparing Example 4 with Example 1, it can be seen that the pore diameter, pore depth and pore density of the micropores are appropriate, which is conducive to forming an appropriate number of micropores with a water droplet-shaped structure, and the shell metal can easily penetrate into the micropores during subsequent die-casting, thereby increasing the bonding strength between the shell metal and the metal inner shell.

[0048] It can be seen from the comparison between Examples 5 and 6 and Example 1 that the speed, pressure and time of die casting affect the appearance and bonding strength of the composite metal shell. When the speed, pressure and time of die casting are appropriate, the appearance of the composite metal shell is smooth, without flow marks, burrs and a complete structure, and the bonding strength of the composite metal shell is also better.

[0049] 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 first metal substrate; Performing hot forging on the first metal substrate to form a metal inner shell, wherein the metal inner shell comprises a main body and a boss, wherein the boss protrudes from the main body; Performing chemical micropore etching on the metal inner shell; An outer shell metal layer including a second metal is formed by die-casting on one side of the metal inner shell provided with the boss, and the boss is embedded in the outer shell metal layer; A groove is formed on a side of the main body away from the boss, and the groove penetrates the main body and extends into the boss.

2. The method for manufacturing a composite metal shell according to claim 1, characterized in that: The first metal substrate includes a titanium alloy, and the second metal includes aluminum.

3. The method for manufacturing a composite metal shell according to claim 1, characterized in that: The step of "performing hot forging on the first metal substrate to form a metal inner shell" includes: heating the first metal substrate to 850°C~950°C, pouring it into a first mold with a temperature of 300°C~350°C, applying pressure to the first mold, and forming the first metal substrate into the metal inner shell.

4. The method for manufacturing a composite metal shell according to claim 1, wherein: The thickness of the main body is 5.4mm~5.7mm, the height of the boss is greater than 0 and less than 5.0mm, the width of the boss is greater than 1.0mm, the top R angle of the boss is greater than 0.5mm, and the bottom R angle of the connection between the boss and the main body is greater than 0.5mm.

5. The method for manufacturing a composite metal shell according to claim 1, characterized in that: The micropores obtained by the chemical micropore etching are in the shape of a water droplet structure.

6. The method for manufacturing a composite metal shell according to claim 5, characterized in that: The pore diameter of the micropores is 60 μm to 160 μm, the pore depth of the micropores is 50 μm to 130 μm, and the pore density of the micropores is 50% to 80%.

7. The method for manufacturing a composite metal shell according to claim 1, wherein: The step of "forming an outer shell metal layer including a second metal by die-casting on a side of the metal inner shell provided with the boss" includes: heating the second metal to 660°C~690°C, pouring it into a second mold with a temperature of 260°C~300°C, and die-casting the second mold with the second metal on a side of the metal inner shell provided with the boss to form the outer shell metal layer, the die-casting speed is 0.8 m / s~1.6m / s, the die-casting pressure is 300 Mpa~500Mpa, and the die-casting time is 0.08s~0.2s.

8. The method for manufacturing a composite metal shell according to claim 1, wherein: The outer shell metal layer has a bonding surface, the metal inner shell covers the bonding surface, and the distance between the groove and the bonding surface is 0.7 mm to 0.8 mm.

9. A composite metal shell, characterized in that: It comprises a metal inner shell and an outer metal layer, the metal inner shell comprises a main body and a boss, the boss protrudes from the main body, the outer metal layer covers the boss and is exposed on the surface of the main body, the boss is embedded in the outer metal layer, and a groove is provided on the side of the metal inner shell away from the boss, the groove passes through the main body and extends into the boss.

10. The composite metal shell according to claim 9, characterized in that: The outer shell metal layer has a bonding surface, the metal inner shell covers the bonding surface, and the distance between the groove and the bonding surface is 0.7 mm to 0.8 mm.

Images