A hydraulic actuator housing and a preparation method thereof

Abstract

The present invention discloses a hydraulic actuator housing and a preparation method thereof, relating to the technical field of metal material preparation, and aiming to solve the problems of weak compressive resistance and poor vibration and noise reduction ability of the existing hydraulic actuator housing. The hydraulic actuator housing includes a foam metal sandwich composite pipe, a foam metal sandwich flange, and a foam metal sandwich end cover; one end of the foam metal sandwich composite pipe is connected to one end of the foam metal sandwich flange, and the foam metal sandwich end cover is connected to the other end of the foam metal sandwich flange; the foam metal sandwich composite pipe includes a first metal pipe layer, a first foam metal layer, and a second metal pipe layer which are sequentially arranged from inside to outside; the first bonding interface between the first metal pipe layer, the first foam metal layer, and the second metal pipe layer is a metallurgical bonding interface. The hydraulic actuator housing provided by the present invention is used to improve the compressive resistance, corrosion resistance, and vibration and noise reduction ability of the hydraulic actuator housing.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material preparation, and particularly relates to a hydraulic actuator housing and a preparation method thereof. Background Art

[0002] As a core transmission component for deep-sea operations and ocean exploration, deep-sea hydraulic actuators not only need to withstand harsh conditions such as high pressure, high temperature, and high humidity, but also have to cope with the dual challenges of seawater corrosion and mechanical vibration. To ensure the survivability of equipment under high hydrostatic pressure in the deep sea, the housing of marine equipment must possess excellent compressive performance. At the same time, to broaden the application scope, these housings also need to have multiple functions under the coupling action of complex multi-physical fields such as force, sound, electricity, and magnetism.

[0003] By combining the advantages of two different metal elements, bimetallic composite materials and bimetallic composite plates have unique properties such as light weight, high strength, corrosion resistance, fatigue resistance, and impact resistance, and have been widely used in fields such as aerospace, shipbuilding, and petrochemical industry. However, their high density, high rigidity, and solid physical characteristics cause sound waves to be more inclined to reflect rather than absorb when contacting their surfaces, especially in the absorption of high-frequency sound waves. In addition, the multi-layer interfaces inside the composite structure may also cause complex reflection and refraction of sound waves, further weakening their sound absorption performance.

[0004] Foam metals, on the other hand, have shown significant advantages in terms of light weight, high strength, energy absorption and vibration damping, good thermal conductivity, and excellent acoustic performance due to their unique pore structures. Especially in the field of acoustics, the high-efficiency sound insulation and absorption effects of foam metals have made them a new star in the field of sound absorption materials. However, the relatively low strength of foam metals limits their load-bearing capacity and energy absorption characteristics. Therefore, the method of filling foam metals into thin-walled structures is usually adopted to improve the overall structural stability, high strength, and buffer vibration damping ability. However, currently, foam metal composite materials mainly rely on mechanical bonding, which is difficult to meet the high standards of high strength, high stability, and high corrosion resistance.

[0005] Therefore, there is an urgent need for a hydraulic actuator housing and a preparation method thereof. Summary of the Invention

[0006] The purpose of the present invention is to provide a hydraulic actuator housing and a preparation method thereof, which are used to improve the compressive capacity, corrosion resistance, and vibration reduction and noise reduction ability of the hydraulic actuator housing during deep-sea operations and ocean exploration.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] In the first aspect, the present invention provides a hydraulic actuator housing, including a foam metal sandwich composite pipe, a foam metal sandwich flange, and a foam metal sandwich end cap;

[0009] One end of the foamed metal sandwich composite pipe is connected to one end of the foamed metal sandwich flange, and the foamed metal sandwich end cover is connected to the other end of the foamed metal sandwich flange;

[0010] The foamed metal sandwich composite pipe includes a first metal pipe layer, a first foamed metal layer, and a second metal pipe layer which are arranged in sequence from inside to outside; the first bonding interface between the first metal pipe layer, the first foamed metal layer, and the second metal pipe layer is a metallurgical bonding interface.

[0011] Optionally, the foamed metal sandwich flange is in a ring-shaped cylinder structure, the foamed metal sandwich end cover is in a cylinder structure, the outer diameter of the foamed metal sandwich flange is the same as the diameter of the foamed metal sandwich end cover, and a plurality of first through holes are uniformly arranged along the circumferential direction on the ring surface of the foamed metal sandwich flange, and a plurality of second through holes corresponding to the first through holes one by one are arranged on the circular surface of the foamed metal sandwich end cover.

[0012] Optionally, the foamed metal sandwich end cover and the foamed metal sandwich flange are obtained by cutting a foamed metal sandwich composite plate, and the foamed metal sandwich composite plate includes a first corrugated metal layer, a second foamed metal layer, and a second corrugated metal layer in sequence from top to bottom. The bonding interface between the first corrugated metal layer, the second corrugated metal layer, and the second foamed metal layer is a second bonding interface of metallurgical bonding, and the second bonding interface is a corrugated interface.

[0013] Compared with the prior art, a hydraulic actuator housing provided by the present invention includes a foamed metal sandwich composite pipe, a foamed metal sandwich flange, and a foamed metal sandwich end cover; the foamed metal sandwich composite pipe includes a first metal pipe layer, a first foamed metal layer, and a second metal pipe layer which are arranged in sequence from inside to outside; the first bonding interface between the first metal pipe layer, the first foamed metal layer, and the second metal pipe layer is a metallurgical bonding interface; the foamed metal sandwich composite pipe in this solution is a foamed metal sandwich material and the bonding interfaces of each structure are metallurgical bonding interfaces. This foamed metal sandwich composite pipe material has high strength, high stability, high corrosion resistance, and excellent sound absorption and vibration damping performance. The hydraulic actuator housing prepared from this material not only has lightweight and high strength and excellent sound absorption and vibration damping performance, but also can maintain excellent performance in extreme environments such as deep sea high pressure, low temperature, and high salt, so as to meet the urgent needs of deep sea hydraulic actuators for high-performance functional housing materials.

[0014] In a second aspect, the present invention provides a preparation method of a hydraulic actuator housing for preparing the hydraulic actuator housing, and the method includes:

[0015] Providing a tube blank composite blank; the tube blank composite blank includes a first metal pipe layer, an annular prefabricated foaming blank, and a second metal pipe layer from inside to outside;

[0016] Heat the tubular blank composite blank to a target temperature, and form it by extruding the tubular blank composite blank. During the forming process, raise the temperature of the first contact interface between the structures of the tubular blank composite blank to a preset temperature, where the preset temperature is greater than or equal to the melting point temperature of the annular prefabricated foamed blank. The first contact interface remelts to form a metallurgical-bonded first bonding interface, obtaining a target composite tubular blank; the target temperature is less than the melting point temperature;

[0017] Place the target composite tubular blank in a heating furnace to foam the intermediate layer of the target composite tubular blank to form a first foam metal layer, obtaining a foam metal sandwich composite tube;

[0018] Assemble the foam metal sandwich composite tube, the foam metal sandwich flange, and the foam metal sandwich end cap to form a hydraulic actuator housing.

[0019] Optionally, the target temperature includes a first target temperature and a second target temperature; the step of heating the tubular blank composite blank to a target temperature and forming it by extruding the tubular blank composite blank, during which the temperature of the first contact interface between the structures of the tubular blank composite blank is raised to a preset temperature, where the preset temperature is greater than or equal to the melting point temperature of the annular prefabricated foamed blank, and the first contact interface remelts to form a metallurgical-bonded first bonding interface, obtaining a target composite tubular blank includes:

[0020] Place the tubular blank composite blank into the first annular inner cavity formed by an extrusion inner die and an extrusion outer die;

[0021] Fix the extrusion outer die through an extruder, start the first induction heating coil arranged on the extrusion inner die to heat the first metal tube layer to the first target temperature; start the second induction heating coil arranged on the extrusion outer die to heat the second metal tube layer to the second target temperature;

[0022] Push one end of the extrusion inner die along the axial direction of the tubular blank composite blank through a punch head, so that the tubular blank composite blank is extruded and formed from the extrusion end of the first annular inner cavity, and the temperature of the first contact interface rises to the preset temperature during the extrusion process, where the preset temperature is greater than or equal to the melting point temperature, and the first contact interface remelts to form a metallurgical-bonded first bonding interface, obtaining a target composite tubular blank, and the extrusion end is used to apply radial pressure to the tubular blank composite blank.

[0023] Optionally, before assembling the foam metal sandwich composite tube, the foam metal sandwich flange, and the foam metal sandwich end cap to form a hydraulic actuator housing, further include:

[0024] Prepare the foam metal sandwich flange and the foam metal sandwich end cap;

[0025] The preparation of the foam metal sandwich flange and the foam metal sandwich end cover includes:

[0026] Providing a composite slab; the composite slab sequentially includes a first corrugated metal layer, a square prefabricated foaming blank, and a second corrugated metal layer from top to bottom; the first corrugated metal layer and the second corrugated metal layer are corrugated metal plates with a corrugated interface on one side.

[0027] Heating the composite slab, heating the first corrugated metal layer to a first target temperature, and heating the second corrugated metal layer to a second target temperature to obtain a composite slab with different temperatures.

[0028] Performing rolling treatment on the composite slab with different temperatures to make the first corrugated metal layer, the square prefabricated foaming blank layer, and the second corrugated metal layer combine tightly, and during the deformation process, the temperature of the second contact interface between the structures of the composite slab with different temperatures rises to a preset temperature, the preset temperature is greater than or equal to the melting point temperature, and the second contact interface remelts to form a metallurgical-bonded second bonding interface to obtain a target composite slab.

[0029] Placing the target composite slab in a heating furnace at a third target temperature and keeping it warm for a preset time to make the middle layer of the target composite slab foam to form a second foam metal layer to obtain a foam metal sandwich composite slab.

[0030] Cutting the foam metal sandwich composite slab according to a preset size to obtain two foam metal sandwich flanges and two foam metal sandwich end covers.

[0031] Optionally, before providing a composite slab, it further includes:

[0032] Preparing a composite slab.

[0033] The preparation of the composite slab includes:

[0034] Providing two metal plates.

[0035] Putting the second foaming powder into a square mold and pressing the second foaming powder to obtain a square prefabricated foaming blank.

[0036] Rolling the two metal plates by a wave-flat rolling mill to obtain a first corrugated metal layer and a second corrugated metal layer; the upper roll of the wave-flat rolling mill is a corrugated roll, and the lower roll is a flat roll.

[0037] Placing the square prefabricated foaming blank between the first corrugated metal layer and the second corrugated metal layer for blank assembly to obtain a composite slab.

[0038] Optionally, the foam metal sandwich composite pipe is prepared by an extrusion tooling, and the extrusion tooling includes:

[0039] The extrusion inner die, the extrusion inner die includes an inner die cylinder body with a T-shaped structure, the inner die cylinder body includes a head and a tail, a cylindrical inner cavity is provided in the tail, a first induction heating coil is provided in the cylindrical inner cavity, an inner die insulating pad is provided between the first induction heating coil and the cylindrical inner cavity, an inner die end cover is provided at one end of the cylindrical inner cavity far from the head, the inner die end cover is connected to the inner die cylinder body through inner die fastening screws, and the inner die end cover is used to form a closed space in the cylindrical inner cavity;

[0040] The extrusion outer die, a second induction heating coil is provided in the extrusion outer die, the inner wall of the extrusion outer die includes a large-diameter section, a ramp section and a small-diameter section, the large-diameter section and the small-diameter section are connected by transition through the ramp section, the large-diameter section of the extrusion outer die is sleeved in cooperation with the head of the inner die cylinder body, a first annular inner cavity is formed between the inner wall of the extrusion outer die and the tail of the extrusion inner die, and one end of the first annular inner cavity close to the small-diameter section is the extrusion end;

[0041] An extruder, which is used to clamp and fix the outer wall of the extrusion outer die;

[0042] A punch head, which is used to push the extrusion inner die to make the tube blank composite blank move axially and be extruded and formed from the extrusion end of the first annular inner cavity.

[0043] Optionally, the main body of the extrusion outer die is an outer die cylinder body, a second annular inner cavity is provided between the inner wall and the outer wall of the large-diameter section, a second induction heating coil is provided in the second annular inner cavity, the second induction heating coil is separated from the second annular inner cavity by an outer die insulating pad, an outer die end cover is provided at one end of the second annular inner cavity far from the small-diameter section, and the outer die end cover is connected to the outer die cylinder body to form a closed space in the second annular inner cavity.

[0044] Optionally, before providing a tube blank composite blank, it further includes:

[0045] Preparing a tube blank composite blank;

[0046] The preparation of the tube blank composite blank includes:

[0047] Mixing metal powder, tackifier and foaming agent powder in a preset ratio to obtain foaming powder; the foaming powder includes first foaming powder and second foaming powder;

[0048] Pour the first foaming powder into a third annular inner cavity formed by a tube blank forming outer die and a tube blank forming inner die, start the first oscillation base of the tube blank sleeving mold, and use an annular punch head to press the foaming powder into an annular pre-foamed blank during the oscillation of the first oscillation base;

[0049] Place the annular pre-foamed blank in the gap between the first metal tube layer and the second metal tube layer of the tube blank composite blank to obtain the tube blank composite blank.

[0050] Compared with the prior art, a preparation method of a hydraulic actuator housing provided by the present invention heats the tube blank composite blank to a target temperature, and extrudes and forms the tube blank composite blank. At the same time, the deformation heat under the extrusion and composite deformation causes the temperature of the first contact interface between the structures of the tube blank composite blank to rise to a preset temperature. The preset temperature is greater than or equal to the melting point temperature of the annular pre-foamed blank, and the first contact interface remelts to form a metallurgical-bonded first bonding interface, obtaining the target composite tube blank. Since the temperature of the first contact interface reaches the preset temperature under the action of deformation heat, the temperature will not rise particularly much, and it can be realized that the temperature of the first contact interface reaches the melting point temperature without reaching the foaming temperature of the intermediate layer of the tube blank composite blank. The intermediate layer of the tube blank composite blank will not foam during the extrusion and composite process. Therefore, under the action of extrusion, the structures of the tube blank composite blank are more tightly combined; then the target composite tube blank is placed in a heating furnace to foam the intermediate layer of the target composite tube blank, thereby obtaining a foam metal sandwich composite tube. Then, the foam metal sandwich composite tube, the foam metal sandwich flange, and the foam metal sandwich end cover are assembled to obtain the hydraulic actuator housing. This method forms a metallurgical bond by remelting the first contact interface of the tube blank composite blank during the extrusion process, and at the same time avoids the premature foaming of the foamed blank in the intermediate layer of the tube blank composite blank, achieving precise control of the foaming process and effectively solving the problem that it is difficult to achieve a tight metallurgical bond between the foam metal and the matrix metal in the prior art. The foam metal sandwich composite tube material prepared by this method has high strength, high stability, high corrosion resistance, and excellent sound absorption and vibration damping performance. The hydraulic actuator housing prepared based on this material not only has light weight, high strength, and excellent sound absorption and vibration damping performance, but also can maintain excellent performance in extreme environments such as deep sea high pressure, low temperature, and high salinity, thus meeting the urgent needs of deep sea hydraulic actuators for high-performance functional housing materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0052] Figure 1 is a schematic structural diagram of a hydraulic actuator housing provided by the present invention;

[0053] Figure 2 is a top view of a foam metal sandwich composite tube provided by the present invention;

[0054] Figure 3 is a schematic structural diagram of a foam metal sandwich composite plate provided by the present invention;

[0055] Figure 4 Top view of the foam metal sandwich flange provided by the present invention;

[0056] Figure 5 Cross-sectional view of the foam metal sandwich flange provided by the present invention;

[0057] Figure 6 Top view of the foam metal sandwich end cap provided by the present invention;

[0058] Figure 7 Cross-sectional view of the foam metal sandwich end cap provided by the present invention;

[0059] Figure 8 Flow chart of the preparation method of a hydraulic actuator housing provided by the present invention;

[0060] Figure 9 Structural schematic diagram of the tube blank composite blank provided by the present invention;

[0061] Figure 10 Forming schematic diagram of the annular prefabricated foamed blank provided by the present invention;

[0062] Figure 11 Cross-sectional schematic diagram of the extrusion inner die provided by the present invention;

[0063] Figure 12 Cross-sectional schematic diagram of the extrusion outer die provided by the present invention;

[0064] Figure 13 Extrusion forming schematic diagram of the target composite tube blank provided by the present invention;

[0065] Figure 14 Preparation schematic diagram of the square prefabricated foamed blank layer provided by the present invention;

[0066] Figure 15 Schematic diagram of the corrugated metal sheet rolling process provided by the present invention;

[0067] Figure 16 Structural schematic diagram of the induction heating device for the foam metal sandwich composite plate provided by the present invention;

[0068] Figure 17 Rolling forming schematic diagram of the composite plate blank provided by the present invention.

[0069] Reference numerals:

[0070] 1 - Foam metal sandwich composite pipe, 11 - First metal pipe layer, 12 - First foam metal layer, 13 - Second metal pipe layer, 14 - Annular prefabricated foaming blank, 2 - Foam metal sandwich flange, 21 - First through hole, 3 - Foam metal sandwich end cap, 31 - Second through hole, 4 - Foam metal sandwich composite plate, 41 - First corrugated metal layer, 42 - Second foam metal layer, 43 - Second corrugated metal layer, 101 - Inner die for tube blank forming, 102 - Outer die for tube blank forming, 103 - First vibration base, 104 - Annular pressing head, 5 - Extrusion inner die, 51 - Inner die cylinder body, 52 - Circular insulating gasket for inner die, 53 - First induction heating coil, 54 - End cap for inner die, 55 - Strip-shaped insulating rubber pad for inner die, 56 - Inner die fastening screw, 6 - Extrusion outer die, 61 - Outer die cylinder body, 62 - Second induction heating coil, 63 - End cap for outer die, 64 - Outer die fastening screw, 65 - Strip-shaped insulating rubber pad for outer die, 66 - Annular insulating gasket for outer die, 7 - Extrusion machine, 8 - Pressing head, 9 - Graphite gasket, 10 - Target composite tube blank, 141 - Square pressing head, 142 - Square die, 143 - Second vibration base, 144 - Square prefabricated foaming blank, 161 - Third induction heating coil, 162 - Fourth induction heating coil. Detailed implementation manners

[0071] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0072] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0073] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined. "Several" means one or more unless otherwise specifically defined.

[0074] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0075] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0076] With the increasing depletion of onshore and coastal resources, global marine powers have shifted their development focus from shallow waters to the deep sea. The rapid progress of deep-sea equipment has made it possible to develop and utilize deep-sea resources on a large scale. However, the extreme environments such as high pressure, low temperature, and high salinity in the deep sea pose severe challenges to the shell design of marine equipment. Currently, foam metal sandwich materials mainly combined by mechanical means are usually used to prepare the shells of deep-sea hydraulic brakes, which are difficult to meet the requirements of high strength, high stability, and high corrosion resistance.

[0077] To solve the above problems, the present invention provides a hydraulic actuator shell and a preparation method thereof, which will be described below with reference to the accompanying drawings.

[0078] See Figure 1 , a hydraulic actuator shell provided by the present invention includes a foam metal sandwich composite pipe 1, a foam metal sandwich flange 2, and a foam metal sandwich end cap 3;

[0079] One end of the foam metal sandwich composite pipe 1 is connected to one end of the foam metal sandwich flange 2, and the foam metal sandwich end cap 3 is connected to the other end of the foam metal sandwich flange 2;

[0080] See Figure 2 , the foam metal sandwich composite pipe includes a first metal pipe layer 11, a first foam metal layer 12, and a second metal pipe layer 13 arranged in sequence from the inside to the outside; the first bonding interface between the first metal pipe layer 11, the first foam metal layer 12, and the second metal pipe layer 13 is a metallurgical bonding interface.

[0081] Among them, the bonding interfaces between the structures of the foam metal sandwich flange 2 are metallurgical bonding interfaces, and the bonding interfaces between the structures of the foam metal sandwich end cap 3 are metallurgical bonding interfaces.

[0082] The first bonding interface is formed after the temperature of the first contact interface rises to a preset temperature under extrusion and the interface remelts. The first contact interface is the contact interface between the various structures of the tube blank composite blank.

[0083] In the above structure, the materials of the first metal tube layer 11 and the second metal tube layer 13 can both be seamless metal tubes.

[0084] From the above structure, it can be seen that the hydraulic actuator housing provided by the present invention is composed of a foam metal sandwich composite pipe, a foam metal sandwich flange, and a foam metal sandwich end cap, which can effectively meet the performance requirements of vibration reduction and sound absorption. At the same time, a variety of outer layer cladding metals can be selected according to different needs, such as titanium / stainless steel, titanium / aluminum, titanium / copper, etc. for a variety of foam metal sandwich composite pipes, flanges, and end caps. The foam metal sandwich composite pipe, the foam metal sandwich flange, and the foam metal sandwich end cap are all made of foam metal sandwich materials, and the bonding interfaces of each structure are metallurgical bonding interfaces. The materials such as the foam metal sandwich composite pipe, the foam metal sandwich flange, and the foam metal sandwich end cap have high strength, high stability, and high corrosion resistance, and have excellent sound absorption and vibration reduction performance. The hydraulic actuator housing prepared from these materials not only has the characteristics of light weight and high strength and excellent sound absorption and vibration reduction performance, but also can maintain excellent performance in extreme environments such as deep sea high pressure, low temperature, and high salt, thus meeting the urgent needs of deep sea hydraulic actuators for high-performance functional housing materials.

[0085] See Figure 3 , the foam metal sandwich flange 2 and the foam metal sandwich end cap 3 in the above structure are cut from the foam metal sandwich composite plate 4. As Figure 3 shown, the foam metal sandwich composite plate 4 sequentially includes a first corrugated metal layer 41, a second foam metal layer 42, and a second corrugated metal layer 43 from top to bottom. The bonding interfaces between the first corrugated metal layer 41 and the second foam metal layer 42 and between the second corrugated metal layer 43 and the second foam metal layer 42 are collectively referred to as the second bonding interface. The second bonding interface is a metallurgical bonding interface and is a corrugated interface. The material of the first corrugated metal layer is the same as that of the first metal tube layer, and the material of the second corrugated metal layer is the same as that of the second metal tube layer.

[0086] See Figures 4 to 7 , the foam metal sandwich flange 2 in the above structure is an annular cylinder structure, the foam metal sandwich end cap 3 is a cylinder structure. The outer diameter of the foam metal sandwich flange 2 is the same as the diameter of the foam metal sandwich end cap 3, and the inner diameter of the foam metal sandwich flange 2 is the same as the inner diameter of the foam metal sandwich composite pipe 1. A plurality of first through holes 21 are uniformly arranged on the circumferential direction of the circular ring surface of the foam metal sandwich flange 2, and a plurality of second through holes 31 corresponding to the first through holes 21 one by one are arranged on the circular surface of the foam metal sandwich end cap 3.

[0087] Combined with Figure 1 , the number of the foam metal sandwich flanges and the foam metal sandwich end caps that make up the hydraulic actuator housing is 2 each. One foam metal sandwich flange is welded to one end of the foam metal sandwich composite pipe, and the other foam metal sandwich flange is welded to the other end of the foam metal sandwich composite pipe. The foam metal sandwich flange and the foam metal sandwich end cap are fastened together by bolts, and the bolts pass through the first through hole and the second through hole.

[0088] The metals in the first foam metal layer and the second foam metal layer in the above structure can be metals or alloys such as aluminum, copper, iron, nickel, titanium, or stainless steel that can form stable bubbles through heating and foaming.

[0089] The foam metal has high sound insulation and sound absorption effects, but the strength of the foam metal is low, which limits its load-bearing capacity and energy absorption characteristics. Currently, the method of adding a thin-walled structure to the foam metal is usually used to improve the stability, strength, and buffer vibration damping ability of the overall structure. However, the structures are only mechanically combined, and the obtained foam metal sandwich composite material cannot meet the high standards of high strength, high stability, and high corrosion resistance in the deep-sea extreme environment; moreover, the preparation of the existing foam metal composite material is difficult to achieve a tight metallurgical bond between the foam metal and the matrix metal.

[0090] To solve this technical problem, the present invention also provides a preparation method for a hydraulic actuator housing, which is used to prepare the above-mentioned hydraulic actuator housing. As Figure 8 shown, a preparation method for a hydraulic actuator housing includes the following steps:

[0091] Step S1: Provide a tube blank composite blank;

[0092] As Figure 9 shown, the tube blank composite blank sequentially includes a first metal tube layer 11, an annular prefabricated foaming blank 14, and a second metal tube layer 13 from the inside to the outside.

[0093] The first metal tube layer and the second metal tube layer are two different high-strength and corrosion-resistant seamless metal tubes.

[0094] Step S2: Heat the tube blank composite blank to a target temperature, and by extruding the tube blank composite blank, the temperature of the first contact interface between the structures of the tube blank composite blank is raised to a preset temperature during the forming process. The preset temperature is greater than or equal to the melting point temperature of the annular prefabricated foaming blank, and the first contact interface remelts to form a metallurgical combined first bonding interface, obtaining a target composite tube blank;

[0095] The melting point temperature is the melting point temperature of the annular prefabricated foaming blank, and the target temperature is less than the melting point temperature;

[0096] Between step S2, it also includes calculating the target temperature according to formula (1) as shown in formula (1):

[0097] (1)

[0098] Wherein, is the target temperature, is the melting point temperature of the annular pre-foamed blank, is the density of the first metal tube layer or the density of the second metal tube layer, is the specific heat capacity of the first metal tube layer or the specific heat capacity of the second metal tube layer.

[0099] When the materials of the first metal tube layer and the second metal tube layer are different, the heating temperatures are different. The target temperature calculated according to the density and specific heat capacity of the first metal tube layer is the first target temperature, and the target temperature calculated according to the density and specific heat capacity of the second metal tube layer is the second target temperature; both the first target temperature and the second target temperature are less than the melting point temperature.

[0100] Step S3: Place the target composite tube blank in a heating furnace to foam the intermediate layer of the target composite tube blank to form a first foam metal layer, obtaining a foam metal sandwich composite tube;

[0101] Specifically, place the target composite tube blank in a heating furnace at the third target temperature for a certain period of time. During the heating process, the foaming agent decomposes to generate bubbles, and the annular pre-foamed blank in the intermediate layer of the target composite tube blank forms a second metal foam layer. After the heat preservation is completed, a foam metal sandwich composite tube with a metallurgical bonding interface is obtained. The third target temperature is greater than or equal to the foaming temperature of the annular pre-foamed blank.

[0102] Step S4: Assemble the foam metal sandwich composite tube, the foam metal sandwich flange, and the foam metal sandwich end cover to form a hydraulic actuator housing.

[0103] It should be noted that the foam metal sandwich composite tube is prepared by steps such as heating, extrusion, and heat preservation foaming of the tube blank composite blank.

[0104] In the preparation method of a hydraulic actuator housing provided by the present invention, since the temperature of the first contact interface reaches the preset temperature under the action of deformation heat, the temperature does not increase particularly much. It can be realized that the temperature of the first contact interface reaches the melting point temperature but does not reach the foaming temperature of the annular pre-foamed blank of the tube blank composite blank. The intermediate layer of the tube blank composite blank will not foam during the extrusion composite process. Therefore, under the action of extrusion, the structures of the tube blank composite blank are more closely combined; then the target composite tube blank is placed in a heating furnace to foam the intermediate layer of the target composite tube blank, thereby obtaining a foam metal sandwich composite tube. Then, the foam metal sandwich composite tube, the foam metal sandwich flange, and the foam metal sandwich end cap are assembled to obtain a hydraulic actuator housing. This method forms a metallurgical bond by remelting the first contact interface of the tube blank composite blank during the extrusion process, while avoiding the premature foaming of the annular pre-foamed blank of the intermediate layer of the tube blank composite blank, achieving precise control of the foaming process, and effectively solving the problem that it is difficult to achieve a tight metallurgical bond between the foam metal and the base metal in the prior art. The foam metal sandwich composite tube material prepared by this method has two high corrosion-resistant seamless metal tubes on the inner and outer layers, and the core layer is filled with foam metal. This foam metal sandwich composite tube has high strength, high stability, high corrosion resistance, and excellent sound absorption and vibration damping performance. The hydraulic actuator housing prepared based on this material not only has lightweight and high strength and excellent sound absorption and vibration damping performance, but also can maintain excellent performance in extreme environments such as deep sea high pressure, low temperature, and high salt, thus meeting the urgent needs of deep sea hydraulic actuators for high-performance functional housing materials.

[0105] Based on the above method, the present invention also provides some specific implementation manners, which will be described in detail next.

[0106] As an optional manner, before providing a tube blank composite blank, it further includes:

[0107] Preparing a tube blank composite blank through a tube blank sleeving die;

[0108] See Figure 10 , the above tube blank sleeving die includes a tube blank forming inner die 101, a tube blank forming outer die 102, an annular press head 104, and a first oscillation base 103. The tube blank forming inner die 101 is a cylindrical structure. The tube blank forming outer die 102 is sleeved on the outer surface of the tube blank forming inner die 101. A third annular inner cavity is formed between the tube blank forming inner die 101 and the tube blank forming outer die 102. The lower surface of the tube blank forming inner die 101 and the lower surface of the tube blank forming outer die 102 are connected to the upper surface of the first oscillation base 103. The annular press head 104 includes a head and a tail. The head of the annular press head 104 can be a metal plate with circular upper and lower surfaces. The tail of the annular press head 104 is an annular cylinder, and the tail of the annular press head 104 is fitted and sleeved with the third annular inner cavity. Preparing the tube blank composite blank includes the following steps:

[0109] Mix metal powder, tackifier and foaming agent powder in a preset ratio to obtain foaming powder;

[0110] Since the foaming powders used for the first foamed metal layer of the foamed metal sandwich composite pipe and the second foamed metal layer of the foamed metal sandwich panel are of the same material, the foaming powder is divided into the first foaming powder and the second foaming powder;

[0111] Pour the first foaming powder into the third annular inner cavity formed by the tube blank forming outer die 102 and the tube blank forming inner die 101, start the first vibration base 103, and use the annular pressing head 104 to press the foaming powder into an annular pre-foamed blank 14 during the vibration of the first vibration base 103;

[0112] Place the annular pre-foamed blank 14 in the gap between the first metal tube layer 11 and the second metal tube layer 13 of the tube blank composite blank to obtain a tube blank composite blank.

[0113] As an optional method, when the materials of the first metal tube layer and the second metal tube layer in the above step S2 are different, the target temperature includes a first target temperature and a second target temperature; the target composite tube blank in step S2 can be prepared by using an extrusion tooling. First, place the tube blank composite blank in the first annular inner cavity between the extrusion inner die and the extrusion outer die, heat the first metal tube layer of the tube blank composite blank to the first target temperature, heat the second metal tube layer of the tube blank composite blank to the second target temperature, and then push one end of the extrusion inner die to drive the tube blank composite blank to be extruded and formed from the extrusion end of the first annular inner cavity, so that the temperature of the first contact interface between the structures of the tube blank composite blank rises to a preset temperature, the preset temperature is greater than or equal to the melting point temperature, and the first contact interface remelts to form a metallurgical combined first bonding interface to obtain the target composite tube blank.

[0114] See Figures 11 - 13 In the above steps, the extrusion tooling used includes:

[0115] The extrusion inner die 5, as Figure 11 shown, the extrusion inner die 5 includes an inner die cylinder body 51 with a T-shaped structure. The inner die cylinder body 51 includes a head and a tail. A cylindrical inner cavity is provided at the tail. A first induction heating coil 53 is provided in the cylindrical inner cavity. An inner die insulating pad is provided between the first induction heating coil 53 and the cylindrical inner cavity. The inner die insulating pad includes an inner die circular insulating gasket 52 and an inner die strip-shaped insulating rubber pad 55. The inner die circular insulating gasket 52 and the inner die strip-shaped insulating rubber pad 55 separate the first induction heating coil from the inner surface of the inner die cylinder body to avoid contact conduction; an inner die end cover 54 is provided at one end of the cylindrical inner cavity far from the head of the inner die cylinder body. The inner die end cover 54 is connected to the inner die cylinder body 51 through an inner die fastening screw 56. The inner die end cover 54 is used to form a closed space for the cylindrical inner cavity;

[0116] The extrusion outer die 6 is provided with a second induction heating coil 62 inside. The inner wall of the extrusion outer die 6 includes a large-diameter section, a ramp section, and a small-diameter section. The large-diameter section and the small-diameter section are connected by a transition through the ramp section. As Figure 13 shown, the large-diameter section of the extrusion outer die 6 is fitted and sleeved with the head of the inner die cylinder. A first annular inner cavity is formed between the inner wall of the extrusion outer die 6 and the tail of the extrusion inner die. One end of the first annular inner cavity close to the small-diameter section is the extrusion end;

[0117] As Figure 12 shown, the main body of the extrusion outer die 6 in the above structure is the outer die cylinder 61. A second annular inner cavity is provided between the inner wall of the large-diameter section of the outer die cylinder and the outer wall of the outer die cylinder. The second induction heating coil 62 is arranged in the second annular inner cavity. The second induction heating coil 62 is separated from the second annular inner cavity by an outer die insulating pad. The outer die insulating pad includes an outer die strip insulating rubber pad 65 and an outer die annular insulating gasket 66. An outer die end cover 63 is arranged at one end of the second annular inner cavity far from the small-diameter section. The outer die end cover 63 is connected to the outer die cylinder 61 by an outer die fastening screw 64 to form a closed space for the second annular inner cavity.

[0118] An extruder 7 for clamping and fixing the outer wall of the extrusion outer die 6;

[0119] A pressure head 8 for pushing the extrusion inner die 5 to make the tubular blank composite blank move axially and extrude and form from the extrusion end of the first annular inner cavity. A graphite gasket 9 is arranged between the pressure head 8 and the extrusion inner die 5.

[0120] Specifically, step S2 can be realized based on the following steps:

[0121] Step S21: Place the tubular blank composite blank into the first annular inner cavity formed by the extrusion inner die and the extrusion outer die;

[0122] Step S22: Fix the extrusion outer die 6 through the extruder 7. Start the first induction heating coil 53 arranged on the extrusion inner die 5 to heat the first metal tube layer of the tubular blank composite blank to the first target temperature; start the second induction heating coil 62 arranged on the extrusion outer die 6 to heat the second metal tube layer of the tubular blank composite blank to the second target temperature;

[0123] The set different first target temperature and second target temperature are less than and close to the melting point temperature of the annular pre-foamed blank.

[0124] Step S23: Push one end of the extrusion inner die along the axial direction of the tube blank composite blank by the indenter, so that the tube blank composite blank is extruded and formed from the extrusion end of the first annular inner cavity, and the temperature of the first contact interface rises to a preset temperature during the extrusion process. The preset temperature is greater than or equal to the melting point temperature, and the first contact interface remelts to form a metallurgical-bonded first bonding interface, obtaining a target composite tube blank. The extrusion end is used to apply radial pressure to the tube blank composite blank.

[0125] The above method uses an extrusion tooling to prepare the target composite tube blank. The extrusion tooling uses independent induction heating coils to simultaneously perform induction heating on different metal tube layers, achieving precise temperature control, ensuring that the deformation resistance of the materials of the first metal tube layer and the second metal tube layer at high temperature is similar to that of the annular pre-foamed blank at normal temperature, effectively avoiding the oxidation of the first contact surface to be compounded during the heating process, and at the same time achieving coordinated deformation, greatly improving the success rate and stability of the preparation of the target composite tube blank. When extruding the tube blank composite blank, the electromagnetic induction frequency can be adjusted according to the extrusion speed, achieving precise on-line temperature control and further improving production efficiency and stability. In addition, the extrusion tooling realizes the preparation of the target composite tube blank through electromagnetic temperature control and extrusion gap coordination, making the target composite tube blank have a metallurgical bonding interface, effectively solving the problem of difficult forming of the tube blank composite blank of the clearance-fitting casing.

[0126] As an optional way, before assembling the foam metal sandwich composite tube, the foam metal sandwich flange and the foam metal sandwich end cover to form a hydraulic actuator housing, it further includes:

[0127] Preparing the foam metal sandwich flange and the foam metal sandwich end cover;

[0128] The preparation of the foam metal sandwich flange and the foam metal sandwich end cover includes the following steps:

[0129] Step S31: Provide a composite plate blank; the composite plate blank includes a first corrugated metal layer, a square pre-foamed blank layer, and a second corrugated metal layer from top to bottom in sequence; the first corrugated metal layer and the second corrugated metal layer are corrugated metal plates with a corrugated interface on one side; the material of the first corrugated metal layer is the same as that of the first metal tube layer, and the material of the second corrugated metal layer is the same as that of the second metal tube layer;

[0130] See Figures 14 - 16 , the steps for preparing the composite plate blank are:

[0131] Provide two metal plates;

[0132] Such as Figure 14As shown, the second foaming powder is placed into the square inner cavity formed by the square mold 142. The second vibration base 143 is started, and the second foaming powder is pressed by the square pressing head 141. Under the continuous vibration of the second vibration base and the extrusion of the square pressing head, the square pre-formed foamed blank 144 is formed.

[0133] The two metal plates are rolled by a wave-flat rolling mill to obtain the first corrugated metal layer and the second corrugated metal layer; as Figure 15 shown, the upper roll of the wave-flat rolling mill is a corrugated roll, and the lower roll is a flat roll; the first corrugated metal layer and the second corrugated metal layer are corrugated metal layers with a corrugated interface on one side.

[0134] The square pre-formed foamed blank is placed between the first corrugated metal layer and the second corrugated metal layer to form a composite blank. The square pre-formed foamed blank is in contact with the corrugated interfaces of the two corrugated metal layers, and the composite blank has a sandwich structure.

[0135] Step S32: The composite blank is heated by a foam metal sandwich composite plate induction heating device. As Figure 16 shown, the first corrugated metal layer is heated to the first target temperature by the third induction heating coil 161 arranged at the top, and the second corrugated metal layer is heated to the second target temperature by the fourth induction heating coil 162 arranged at the bottom to obtain a non-isothermal composite blank.

[0136] Step S33: As Figure 17 shown, the non-isothermal composite blank is rolled to make the first corrugated metal layer, the square pre-formed foamed blank and the second corrugated metal layer combine tightly, and the temperature of the second contact interface between the structures of the non-isothermal composite blank rises to a preset temperature. The preset temperature is greater than or equal to the melting point temperature, and the second contact interface remelts to form a metallurgical-bonded second bonding interface to obtain the target composite plate; the square pre-formed foamed blank and the annular pre-formed foamed blank are made of the same material, have the same melting point, and the same foaming temperature.

[0137] The target composite plate is placed in a heating furnace at the third target temperature and kept warm for a preset time to make the square pre-formed foamed blank in the middle layer of the target composite plate foam to form the second foam metal layer, obtaining a foam metal sandwich composite plate; the third target temperature is greater than or equal to the foaming temperature.

[0138] In the above steps S32 and S33, separate induction heating coils are used to heat the first corrugated metal layer and the second corrugated metal layer of the composite slab to different temperatures, achieving precise control of the temperature before rolling and compounding, ensuring that the deformation resistances of the first corrugated metal layer and the second corrugated metal layer at high temperature are close to those of the square prefabricated foamed blank at normal temperature, effectively avoiding oxidation of the surfaces to be compounded during heating, realizing coordinated deformation, and greatly improving the success rate and stability of preparing the foamed metal sandwich composite plate. The surfaces of the foamed metal sandwich flange and the foamed metal sandwich end cap prepared by the above steps are two high-strength and corrosion-resistant metal plates, and the core layer is filled with foamed metal, having high strength, high stability, high corrosion resistance, and excellent sound absorption and vibration damping performance.

[0139] Cut the foamed metal sandwich composite plate according to the preset size to obtain two foamed metal sandwich flanges and two foamed metal sandwich end caps.

[0140] Next, a preparation method of a hydraulic actuator housing provided by the present invention will be described in detail by way of example.

[0141] A TA1 / 304 foamed aluminum sandwich housing for a deep-sea hydraulic actuator is composed of a TA1 / 304 foamed metal sandwich composite pipe, a TA1 / 304 foamed metal sandwich flange, and a TA1 / 304 foamed metal sandwich end cap. The TA1 / 304 foamed metal sandwich composite pipe and the TA1 / 304 foamed metal sandwich flange are connected by welding, and the TA1 / 304 foamed metal sandwich flange and the TA1 / 304 foamed metal sandwich end cap are connected by bolts and sealing gaskets. Its preparation method consists of two parts:

[0142] The first part is the preparation method of the TA1 / 304 foamed metal sandwich composite pipe. The material of the first metal layer of the foamed metal sandwich composite pipe is a TA1 seamless pipe, and the material of the second metal layer is a 304 stainless steel seamless pipe. The method includes the following steps:

[0143] Step 11: Preparation of foaming powder: Select metal Ca as a tackifier and titanium metal hydride as a foaming agent powder, and perform pre-oxidation treatment on the foaming agent powder to delay its decomposition rate during the heating and foaming process. Mix the aluminum alloy powder, the tackifier, and the foaming agent powder according to the mass percentages of 95%, 3%, and 2% to obtain the foaming powder. Then pour the foaming powder into the third annular inner cavity formed by the tube blank forming outer mold and the tube blank forming inner mold, and use an annular pressing head to press it into an annular prefabricated foamed blank with an outer diameter of 178 mm, a wall thickness of 18 mm, and a length of 500 mm. During the pressing process, the first vibration base continuously works to ensure obtaining a compact foamed aluminum annular prefabricated foamed blank;

[0144] Step 12: Blank assembling: Select a TAI seamless tube with an outer diameter of 200 mm, a wall thickness of 10 mm, and a length of 500 mm, and a 304 stainless steel seamless tube with an outer diameter of 140 mm, a wall thickness of 10 mm, and a length of 500 mm. Use alcohol to clean and remove the oil stain, then polish the inner surface of the TAI seamless tube and the outer surface of the 304 stainless steel seamless tube. Assemble the blanks in a gap sequence of the TAI seamless tube, the annular pre-foamed blank, and the 304 stainless steel seamless tube to obtain a TAI / 304 foam aluminum sandwich tube blank composite blank;

[0145] Step 13: Calculate the first target temperature and the second target temperature according to formula (1). Among them, the density of the TAI seamless tube in the TAI / 304 foam aluminum sandwich tube blank composite blank is 4.51 g / cm3, and the specific heat capacity is 0.526 J / g. The density of the 304 stainless steel seamless tube in the TAI / 304 foam aluminum sandwich tube blank composite blank is 7.93 g / cm3, and the specific heat capacities are 0.5 J / g respectively. The melting point temperature of the annular pre-foamed blank is 660 °C. Substituting these data into formula (1), the first target temperature of the TAI seamless tube is 550 °C, and the second target temperature of the 304 stainless steel seamless tube is 600 °C.

[0146] Step 13: Electromagnetic temperature-controlled extrusion compounding: Insert the TAI / 304 tube blank composite blank into an extrusion inner die with an outer diameter of 110 mm, and send the extrusion inner die and the tube blank composite blank together into the undeformed area of the extrusion outer die. Then start the induction heating coils set in the extrusion inner die and the extrusion outer die, heat the TAI seamless tube and the 304 stainless steel seamless tube to 550 °C and 600 °C respectively, turn off the induction heating coils, and at the same time start the extruder. The pressure head pushes the extrusion inner die to drive the tube blank composite blank through the extrusion outer die with an inner diameter of 170 mm in the forming area, and extrude a seamless metal composite tube blank from the extrusion die; Before starting the extrusion compounding, the TAI seamless tube and the 304 stainless steel seamless tube are heated to 550 °C and 600 °C respectively, and the temperatures are both lower than the melting point temperature of the pre-foamed blank material, 660 °C. After the induction heating is completed, the temperature of the annular pre-foamed blank in the middle layer of the tube blank composite blank is lower than the temperature of the seamless tube. Since titanium has a lower thermal conductivity and a higher coefficient of thermal expansion, it is easier to absorb heat and quickly heat up during the plastic deformation process. Under the same conditions, titanium usually heats up faster than stainless steel. Therefore, the TAI seamless tube is set to have a higher starting temperature than the 304 stainless steel seamless tube. Under the action of the extrusion compounding deformation heat, the contact interface temperature between the TAI seamless tube, the 304 stainless steel seamless tube and the annular pre-foamed blank rises above the melting point temperature of the annular pre-foamed blank, realizing interface remelting to form a metallurgical bond, but the annular pre-foamed blank does not reach the foaming temperature of 550 °C and will not pre-foam;

[0147] Step 14 Heat preservation and foaming forming: Place the target composite tube blank prepared in Step 13 in a heating furnace at a temperature of 550 °C for heat preservation for 3 minutes. During the heating process, the annular prefabricated foaming blank decomposes to generate bubbles, and the prefabricated foaming blank in the middle layer forms foamed aluminum. After the heat preservation and foaming are completed, cut off the ends to obtain a TA1 / 304 foamed aluminum sandwich composite tube with interfacial metallurgical bonding;

[0148] The second part is a preparation method for a TA1 / 304 foamed aluminum sandwich flange and a TA1 / 304 foamed aluminum sandwich end cover, which includes the following steps:

[0149] Step 21 Preparation of prefabricated foaming blank: Select metallic Ca as the viscosity-increasing agent and titanium metal hydride as the foaming agent powder. Perform pre-oxidation treatment on the foaming agent powder to delay its decomposition rate during the heating and foaming process. Mix the aluminum alloy powder, viscosity-increasing agent, and foaming agent powder according to the mass percentages of 95%, 3%, and 2% to obtain foaming powder. Then use a square mold to press the foaming powder to obtain a square prefabricated foaming blank of foamed aluminum with dimensions of 250 mm * 250 mm * 10 mm;

[0150] Step 22 Preparation of prefabricated corrugated metal plates: Roll a TA1 titanium plate and a 304 stainless steel plate with dimensions of 250 * 250 mm * 5 mm using a wave-flat rolling mill with a corrugated roll on the upper roll and a flat roll on the lower roll to obtain two TA1 titanium plates and 304 stainless steel plates with a corrugated interface on one side;

[0151] Step 23 Grinding and blank assembly: Use a wire brush to grind the corrugated interfaces of the TA1 titanium plate and the 304 stainless steel plate. After removing the oxides on the corrugated interfaces, stack and assemble them in the order of the TA1 titanium plate, the square prefabricated foaming blank of foamed aluminum, and the 304 stainless steel plate to obtain a TA1 / 304 foamed aluminum sandwich plate composite blank. Ensure that the corrugated interface is in contact with the square prefabricated foaming blank of foamed aluminum during blank assembly;

[0152] Step 24 Electromagnetic induction heating of the composite blank: Place the TA1 / 304 foamed aluminum sandwich plate composite blank in an induction heating device, turn on the induction heating coils at the top and bottom, and heat the TA1 titanium plate and the 304 stainless steel plate to the target temperatures of 550 °C and 600 °C respectively. The target temperatures are both lower than the melting point temperature of 660 °C of the square prefabricated foaming blank. Since titanium has a lower thermal conductivity and a higher coefficient of thermal expansion, it is easier to absorb heat and quickly heat up during the rolling process. Under the same conditions, titanium usually heats up faster than stainless steel, so the heating temperature of the TA1 titanium plate is higher than that of the 304 stainless steel plate;

[0153] Step 25: Rolling compounding: Feed the heated TA1 / 304 foam aluminum sandwich plate composite blank into a two-high flat rolling mill for rolling compounding. After cooling, a composite metal slab is finally obtained. Under the action of rolling deformation, the deformation heat causes the contact interface temperature between the TA1 titanium plate and the 304 stainless steel plate and the square pre-formed foam blank to rise above the melting point temperature of the square pre-formed foam blank, realizing interface remelting to form a metallurgical bond. However, the square pre-formed foam blank does not reach the foaming temperature of 550 °C and will not pre-foam.

[0154] Step 26: Insulation foaming and forming: Place the composite metal slab in a heating furnace at a temperature of 550 °C for 3 minutes of insulation. During the heating process, the square pre-formed foam blank decomposes to generate bubbles, and the square pre-formed foam blank in the middle layer forms foam metal aluminum. After the insulation foaming is completed, a foam aluminum sandwich composite plate is obtained. The material of the first corrugated metal layer is TA1, and the material of the second corrugated metal layer is 304 stainless steel. Cut and process the foam aluminum sandwich composite plate to obtain a TA1 / 304 foam aluminum sandwich flange and a TA1 / 304 foam aluminum sandwich end cover with a corrugated metallurgical bond interface. The outer diameter of the foam metal sandwich flange is 240 mm, the inner diameter is 100 mm, and the thickness is 15 mm. The diameter of the foam metal sandwich end cover is 240 mm, and the thickness is 15 mm. Six through holes with a diameter of 8 mm are machined on the circumference with a diameter of 230 mm of the foam metal sandwich flange and the foam metal sandwich end cover, and bolts pass through the through holes for fastening connection.

[0155] Finally, clean the prepared TA1 / 304 foam aluminum sandwich composite pipe, TA1 / 304 foam aluminum sandwich flange, and TA1 / 304 foam aluminum sandwich end cover, and then weld the TA1 / 304 foam aluminum sandwich flange to both ends of the TA1 / 304 foam aluminum sandwich composite pipe, and use bolts to connect the TA1 / 304 foam aluminum sandwich flange and the TA1 / 304 foam aluminum sandwich end cover for sealing to obtain the required TA1 / 304 foam aluminum sandwich shell.

[0156] In the description of the above embodiments, the specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

Claims

1. A hydraulic actuator housing, characterized in that, It includes a foam metal sandwich composite pipe, a foam metal sandwich flange, and a foam metal sandwich end cap; One end of the foam metal sandwich composite pipe is connected to one end of the foam metal sandwich flange, and the foam metal sandwich end cap is connected to the other end of the foam metal sandwich flange; the foam metal sandwich flange is a ring-shaped cylinder structure, the foam metal sandwich end cap is a cylinder structure, the outer diameter of the foam metal sandwich flange is the same as the diameter of the foam metal sandwich end cap, and a plurality of first through holes are uniformly arranged along the circumferential direction on the ring surface of the foam metal sandwich flange, and a plurality of second through holes corresponding to the first through holes one by one are arranged on the circular surface of the foam metal sandwich end cap; the foam metal sandwich end cap and the foam metal sandwich flange are obtained by cutting a foam metal sandwich composite plate, and the foam metal sandwich composite plate sequentially includes a first corrugated metal layer, a second foam metal layer, and a second corrugated metal layer from top to bottom. The bonding interface between the first corrugated metal layer, the second corrugated metal layer, and the second foam metal layer is a metallurgical bonding second bonding interface, and the second bonding interface is a corrugated interface; The foam metal sandwich composite pipe includes a first metal pipe layer, a first foam metal layer, and a second metal pipe layer arranged in sequence from inside to outside; the first bonding interface between the first metal pipe layer, the first foam metal layer, and the second metal pipe layer is a metallurgical bonding interface; The foam metal composite pipe is obtained by placing a target composite pipe blank in a heating furnace and foaming the middle layer of the target composite pipe blank to form a first foam metal layer; The target composite pipe is placed in a first annular inner cavity formed by an extrusion inner die and an extrusion outer die; the extrusion outer die is fixed by an extruder, and a first induction heating coil arranged on the extrusion inner die is started to heat the first metal pipe layer to a first target temperature; A second induction heating coil arranged on the extrusion outer die is started to heat the second metal pipe layer to a second target temperature; one end of the extrusion inner die is pushed by a punch to move axially along the pipe blank composite blank, so that the pipe blank composite blank is extruded and formed from the extrusion end of the first annular inner cavity, and the first contact interface is heated to a preset temperature during the extrusion process, and the first contact interface remelts to form a metallurgical bonding first bonding interface; the preset temperature is greater than or equal to the melting point temperature of the annular pre-foamed blank, the target temperature includes the first target temperature and the second target temperature, and both the first target temperature and the second target temperature are less than the melting point temperature; The pipe blank composite blank includes a first metal pipe layer, an annular pre-foamed blank, and a second metal pipe layer from inside to outside; The foam metal sandwich composite pipe is prepared by an extrusion tooling, and the extrusion tooling includes: Extrusion inner die, the extrusion inner die includes an inner die cylinder body with a T-shaped structure, the inner die cylinder body includes a head and a tail, a cylindrical inner cavity is provided at the tail, a first induction heating coil is arranged in the cylindrical inner cavity, an inner die insulating pad is arranged between the first induction heating coil and the cylindrical inner cavity, an inner die end cover is arranged at one end of the cylindrical inner cavity away from the head, and the inner die end cover is connected to the inner die cylinder body through inner die fastening screws, and the inner die end cover is used to form a closed space in the cylindrical inner cavity; Extrusion outer die, a second induction heating coil is arranged in the extrusion outer die, the inner wall of the extrusion outer die includes a large-diameter section, a slope section and a small-diameter section, the large-diameter section and the small-diameter section are connected by transition through the slope section, the large-diameter section of the extrusion outer die is sleeved in cooperation with the head of the inner die cylinder body, a first annular inner cavity is formed between the inner wall of the extrusion outer die and the tail of the extrusion inner die, and one end of the first annular inner cavity close to the small-diameter section is the extrusion end; Extrusion machine, used to clamp and fix the outer wall of the extrusion outer die; Press head, used to push the extrusion inner die to make the tube blank composite blank move axially and extrude and form from the extrusion end of the first annular inner cavity.

2. A preparation method of a hydraulic actuator housing, characterized in that, For preparing the hydraulic actuator housing described in claim 1, the method includes: Providing a tube blank composite blank; the tube blank composite blank includes a first metal tube layer, an annular pre-formed foam blank and a second metal tube layer from inside to outside; Heating the tube blank composite blank to a target temperature, and by extruding and forming the tube blank composite blank, the temperature of the first contact interface between the structures of the tube blank composite blank is raised to a preset temperature during the forming process, the preset temperature is greater than or equal to the melting point temperature of the annular pre-formed foam blank, and the first contact interface remelts to form a metallurgical-bonded first bonding interface to obtain a target composite tube blank; the target temperature is less than the melting point temperature; Placing the target composite tube blank in a heating furnace to foam the intermediate layer of the target composite tube blank to form a first foam metal layer to obtain a foam metal sandwich composite tube; Assembling the foam metal sandwich composite tube, the foam metal sandwich flange and the foam metal sandwich end cover to form a hydraulic actuator housing; The target temperature includes a first target temperature and a second target temperature; heating the tube blank composite blank to the target temperature, and by extruding and forming the tube blank composite blank, the temperature of the first contact interface between the structures of the tube blank composite blank is raised to a preset temperature during the forming process, the preset temperature is greater than or equal to the melting point temperature of the annular pre-formed foam blank, and the first contact interface remelts to form a metallurgical-bonded first bonding interface to obtain a target composite tube blank includes: Placing the tube blank composite blank into the first annular inner cavity formed by the extrusion inner die and the extrusion outer die; Fixing the extrusion outer die through the extrusion machine, starting the first induction heating coil arranged in the extrusion inner die to heat the first metal tube layer to the first target temperature; starting the second induction heating coil arranged in the extrusion outer die to heat the second metal tube layer to the second target temperature; By pushing one end of the extrusion inner die with a punch to move axially along the tube blank composite blank, the tube blank composite blank is extruded and formed from the extrusion end of the first annular inner cavity, and the temperature of the first contact interface rises to a preset temperature during the extrusion process. The preset temperature is greater than or equal to the melting point temperature, and the first contact interface remelts to form a metallurgical-bonded first bonding interface, obtaining a target composite tube blank. The extrusion end is used to apply radial pressure to the tube blank composite blank; The main body of the extrusion outer die is an outer die cylinder body. A second annular inner cavity is provided between the inner wall and the outer wall of the large-diameter section. A second induction heating coil is arranged in the second annular inner cavity. The second induction heating coil is separated from the second annular inner cavity by an outer die insulating pad. An outer die end cover is arranged at one end of the second annular inner cavity far from the small-diameter section. The outer die end cover is connected to the outer die cylinder body to form a closed space for the second annular inner cavity.

3. The preparation method of the hydraulic actuator housing according to claim 2, characterized in that, Before assembling the foam metal sandwich composite tube, the foam metal sandwich flange, and the foam metal sandwich end cover to form a hydraulic actuator housing, it further includes: Preparing the foam metal sandwich flange and the foam metal sandwich end cover; The preparation of the foam metal sandwich flange and the foam metal sandwich end cover includes: Providing a composite plate blank; the composite plate blank sequentially includes a first corrugated metal layer, a square prefabricated foaming blank, and a second corrugated metal layer from top to bottom; the first corrugated metal layer and the second corrugated metal layer are corrugated metal plates with a corrugated interface on one side; Heating the composite plate blank, heating the first corrugated metal layer to a first target temperature, and heating the second corrugated metal layer to a second target temperature to obtain a non-isothermal composite plate blank; Performing a rolling process on the non-isothermal composite plate blank to make the first corrugated metal layer, the square prefabricated foaming blank layer, and the second corrugated metal layer combine tightly, and the temperature of the second contact interface between the structures of the non-isothermal composite plate blank rises to a preset temperature during the forming process. The preset temperature is greater than or equal to the melting point temperature, and the second contact interface remelts to form a metallurgical-bonded second bonding interface, obtaining a target composite plate; Placing the target composite plate in a heating furnace at a third target temperature and keeping it warm for a preset time to make the intermediate layer of the target composite plate foam to form a second foam metal layer, obtaining a foam metal sandwich composite plate; Cutting the foam metal sandwich composite plate according to a preset size to obtain two foam metal sandwich flanges and two foam metal sandwich end covers.

4. The preparation method of the hydraulic actuator housing according to claim 3, characterized in that Before providing a composite plate blank, it further includes: Preparing the composite plate blank; The preparation of the composite plate blank includes Providing two metal plates; Putting the second foaming powder into a square mold and pressing the second foaming powder to obtain a square prefabricated foaming blank; Rolling the two metal plates with a wave-flat rolling mill to obtain a first corrugated metal layer and a second corrugated metal layer; the upper roll of the wave-flat rolling mill is a corrugated roll, and the lower roll is a flat roll; Placing the square prefabricated foaming blank between the first corrugated metal layer and the second corrugated metal layer for blank assembling to obtain a composite plate blank.

5. The preparation method of the hydraulic actuator housing according to claim 2, characterized in that, Before providing a tube blank composite blank, it further includes: Preparing the tube blank composite blank; The prepared tube blank composite blank includes: Mixing metal powder, a tackifier, and foaming agent powder in a preset ratio to obtain foaming powder; the foaming powder includes first foaming powder and second foaming powder; Pouring the first foaming powder into a third annular inner cavity formed by an outer die for tube blank forming and an inner die for tube blank forming, starting the first oscillation base of the tube blank sleeve mold, and using an annular pressing head to press the foaming powder into an annular pre-formed foamed blank during the oscillation of the first oscillation base; Placing the annular pre-formed foamed blank in the gap between the first metal tube layer and the second metal tube layer of the tube blank composite blank to obtain the tube blank composite blank.

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