Preparation process and preparation tooling of continuous furnace bimetallic cylinder and hydraulic cylinder

Abstract

This invention provides a process, tooling, and hydraulic cylinder for preparing bimetallic cylinder bodies for continuous furnaces, relating to the field of hydraulic cylinder processing. Addressing the issue that current bimetallic cylinder body preparation processes are unsuitable for continuous furnace production, this invention utilizes a heat shield to separate the steel substrate and copper raw material. After entering the continuous furnace for heating, the copper raw material, located outside the heat shield, can rapidly heat up and melt, while the steel substrate heats up more slowly, remaining below the liquidus temperature of the copper. The molten copper-containing metal, after dripping onto the steel substrate, forms a temperature gradient under the relatively low temperature of the steel substrate, thus solidifying from bottom to top to form a high-density copper coating. No additional human intervention is required during the transport process, meeting the requirements for continuous furnace production of bimetallic cylinder bodies.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder processing, specifically to a preparation process, preparation tooling, and hydraulic cylinder for a continuous furnace bimetallic cylinder body. Background Technology

[0002] The main body of the hydraulic cylinder is a bimetallic cylinder body, with an appearance like... Figure 1 As shown, the composite material includes a copper cladding layer made of copper alloy and a steel substrate made of iron alloy, with the copper cladding layer covering the end face of the steel substrate. The solid-liquid composite method is a commonly used method for preparing copper-steel composite materials. It utilizes the fact that copper has a lower melting point than steel; when the temperature reaches copper's melting point, the copper melts and covers the surface of the steel, achieving the composite effect. Compared to the traditional solid-solid composite sintering production method, this method has advantages such as high efficiency and high environmental friendliness.

[0003] A continuous mesh belt heating furnace is used to composite the copper cladding and the steel substrate. The steel substrate and the copper block used to make the copper cladding are placed together in the heating furnace for heating. During the heat preservation process, the steel substrate, as the base part of the cylinder, is heated together with the copper block. When the copper block is completely melted, the steel substrate remains solid. Subsequently, the copper-containing molten metal flows and completely covers the upper surface of the steel substrate. After heating, the cylinder enters the cooling section. However, due to the solid-liquid transition of the copper alloy, defects are prone to occur during the solidification of the copper-containing molten metal. Because of the large volume difference between the steel substrate and the copper cladding, and because copper has better thermal conductivity than steel, the surface layer of the copper-containing molten metal in contact with the cooling section environment will cool and solidify preferentially, while the copper-containing molten metal in contact with the steel substrate will remain at the same temperature as the steel. A temperature gradient with a gradual increase in temperature from top to bottom is formed in the copper-containing molten metal, resulting in a solidification direction from top to bottom when the copper-containing molten metal cools. The copper-containing molten metal at the interface between the copper-containing molten metal and the steel substrate becomes the last solidification area. There is a large shrinkage porosity at the copper-steel interface, causing premature failure of the parts. Chinese patent (publication number: CN114042918A) discloses a process for preparing copper-steel bimetallic components. The steel substrate is fixed in the deposition chamber, then filled with protective gas and preheated to a set temperature, which is lower than the solidus temperature of the steel material. The copper-containing molten metal is deposited on the surface of the steel substrate to achieve preliminary composite. After composite, it is preheated and then kept at a certain temperature. However, the steel substrate and the copper-containing molten metal need to be operated separately, which is not suitable for continuous furnaces. There is no space in the continuous furnace to operate the steel substrate and the copper-containing metal separately, which makes it difficult to achieve the current deposition of copper-containing molten metal, affecting its application in continuous furnaces and failing to meet the needs of large-scale production. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a process, tooling, and hydraulic cylinder for preparing bimetallic cylinder bodies in a continuous furnace. A heat shield separates the steel substrate and copper raw material, allowing them to heat rapidly and melt inside the continuous furnace. The steel substrate, located outside the heat shield, heats up more slowly, remaining below the liquidus temperature of the copper. The molten copper, dripping onto the steel substrate, forms a temperature gradient due to the relatively low temperature of the steel substrate, solidifying from bottom to top to form a dense copper coating. This process eliminates the need for additional human intervention during transport, meeting the requirements for continuous furnace production of bimetallic cylinder bodies.

[0005] The first objective of this invention is to provide a process for preparing a bimetallic cylinder body for a continuous furnace, employing the following method:

[0006] A process for manufacturing a bimetallic cylinder block in a continuous furnace includes:

[0007] Fabrication of the steel substrate;

[0008] The steel substrate is placed on the continuous furnace conveyor belt and covered with a heat insulation cover, and a container is arranged on the heat insulation cover.

[0009] The copper raw materials for making the copper cladding are placed in a container and fed into a continuous furnace for heating.

[0010] The copper raw material is heated to a temperature above the liquidus temperature of copper until it melts into a copper-containing metal melt. The steel substrate is heated and its temperature is maintained below the liquidus temperature of copper.

[0011] The copper-containing molten metal passes through the heat insulation cover and falls onto the steel substrate. The copper-containing molten metal solidifies on the steel substrate in a bottom-up order, forming a copper coating on the steel substrate.

[0012] The steel substrate and copper cladding are fed into the cooling section of a continuous furnace to obtain the cylinder body.

[0013] Furthermore, the heat insulation cover is separated from the steel substrate, and the air between the heat insulation cover and the steel substrate together prevents the continuous furnace from heating the steel substrate, keeping the temperature of the steel substrate below the liquidus temperature of the copper material.

[0014] Furthermore, the steel substrate, heat insulation cover, container, and copper raw material move together within the continuous furnace.

[0015] Furthermore, the container is funnel-shaped, with an opening at the top for placing copper raw materials, and an opening at the bottom after passing through a heat insulation cover, allowing copper-containing molten metal to fall onto the steel substrate.

[0016] Furthermore, after the temperature of all the copper-containing molten metal falling onto the steel substrate is lower than the liquid phase temperature of the copper material, it is then sent to the cooling section of the continuous furnace.

[0017] Furthermore, after the copper-containing molten metal falls onto the steel substrate, the copper-containing molten metal in contact with the steel substrate solidifies first, forming a temperature gradient in which the temperature gradually increases from the direction close to the steel substrate to the direction far away from the steel substrate.

[0018] The second objective of this invention is to provide a tooling for preparing a bimetallic cylinder body for a continuous furnace, employing the following scheme:

[0019] The tooling for preparing a continuous furnace bimetallic cylinder body as described in the first objective includes a continuous furnace, a heat shield, and a container.

[0020] The continuous furnace includes a heating section, a heat preservation section, and a cooling section that are sequentially distributed along the conveying direction;

[0021] The heat insulation cover has an internal cavity for housing the steel substrate;

[0022] The container, with its main body located outside the heat shield, is used to hold copper raw materials for making copper cladding. The container's outlet extends through the heat shield into the cavity.

[0023] Furthermore, the heat insulation cover is a shell structure with an opening at the bottom and an opening at the top. The bottom opening of the heat insulation cover forms a cavity with the conveyor belt of the continuous furnace, and the top opening of the heat insulation cover is used for the outlet of the container to pass through.

[0024] Furthermore, the container is funnel-shaped, with a conical groove at one end and a drain pipe at the other end. The groove area is located outside the heat insulation cover, and one end of the drain pipe is connected to the bottom of the groove, while the other end passes through the heat insulation cover to form the outlet of the container.

[0025] A third objective of the present invention is to provide a hydraulic cylinder manufactured by the process for preparing a continuous furnace bimetallic cylinder body as described in the first objective.

[0026] Compared with the prior art, the advantages and positive effects of this invention are:

[0027] (1) To address the problem that the current bimetallic cylinder preparation process is not suitable for continuous furnace production, a heat shield is used to separate the steel substrate and copper raw material. After entering the continuous furnace for heating, the copper raw material is located outside the heat shield and can heat up and melt rapidly, while the steel substrate heats up more slowly and remains below the liquidus temperature of the copper material. After the copper raw material melts, the copper-containing molten metal drips onto the steel substrate and forms a temperature gradient under the action of the relatively low-temperature steel substrate, thus solidifying in a bottom-up order to form a high-density copper coating. No additional human intervention is required during the transportation process, which meets the requirements of continuous furnace production of bimetallic cylinders.

[0028] (2) Since the copper raw material used in this invention is a copper alloy raw material, when tin-lead bronze is used as the raw material for copper cladding, the second phase Pb phase tends to aggregate in the high-temperature region under the action of temperature gradient. In this invention, the temperature gradient of the copper-containing metal melt increases from bottom to top, so that the Pb phase can be evenly dispersed and the aggregation to the copper-steel composite interface can be slowed down. At the same time, since the upper temperature is higher, that is, the upper part is in liquid state and the lower copper-steel composite interface is in semi-solid or solid state, under the action of surface tension, the Pb phase can aggregate to the liquid region, thereby achieving uniform dispersion and ensuring the interfacial bonding force. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0030] Figure 1 This is a schematic diagram of the bimetallic cylinder body in Embodiments 1-3 of the present invention.

[0031] Figure 2 This is a schematic diagram of copper-containing molten metal dripping onto a steel substrate inside a container in Embodiments 1 and 2 of the present invention.

[0032] Figure 3 The graphs show the temperature changes of the steel substrate and the copper in the container in the continuous furnace in Examples 1 and 2 of the present invention.

[0033] Figure 4 Metallographic images of the copper cladding obtained by the continuous furnace bimetallic cylinder preparation process in Examples 1 and 2 of this invention.

[0034] Figure 5 This is a metallographic image of the copper cladding produced by a conventional casting process.

[0035] In the diagram, 1. steel substrate, 2. copper cladding, 3. container, 4. copper-containing molten metal, and 5. heat insulation cover. Detailed Implementation

[0036] Example 1

[0037] In a typical embodiment of the present invention, such as Figures 1-5 As shown, a process for preparing a bimetallic cylinder block for a continuous furnace is presented.

[0038] Currently, the fabrication of bimetallic cylinders requires separate temperature control for the steel and copper materials, along with additional operations during deposition, resulting in low production efficiency and unsuitability for continuous furnace applications. Continuous furnaces struggle to provide the necessary operational space for depositing molten copper, hindering large-scale production of copper-steel bimetallic cylinders. Therefore, this embodiment provides a continuous furnace bimetallic cylinder fabrication process. This process involves placing both the steel substrate 1 and the copper raw material for the copper coating 2 into the continuous furnace. A heat shield 5 separates the steel substrate 1 and the copper raw material, creating differential heating suitable for continuous furnace production. After the copper raw material melts, it is introduced onto the lower-temperature steel substrate 1 for deposition, establishing a first-contact, first-cooling, first-solidification deposition method. This reduces the shrinkage tendency at the copper-steel interface and minimizes defects in the deposited parts.

[0039] like Figure 1 As shown, a process for manufacturing a bimetallic cylinder body for a continuous furnace includes:

[0040] Fabrication of steel substrate 1;

[0041] The steel substrate 1 is placed on the continuous furnace conveyor belt and covered with a heat insulation cover 5. A container 3 is arranged on the heat insulation cover 5.

[0042] The copper raw materials for making copper cladding 2 are placed in container 3 and fed into a continuous furnace for heating.

[0043] The copper raw material is heated to a temperature above the liquidus temperature of copper until it melts into a copper-containing metal melt 4. The steel substrate 1 is heated and its temperature is maintained below the liquidus temperature of copper.

[0044] The copper-containing molten metal 4 passes through the heat insulation cover 5 and falls onto the steel substrate 1. The copper-containing molten metal 4 solidifies on the steel substrate 1 in a bottom-up order, forming a copper coating 2 on the steel substrate 1.

[0045] The steel substrate 1 and the copper cladding 2 are fed into the cooling section of a continuous furnace to obtain the cylinder body.

[0046] It should be noted that the bottom-to-top solidification sequence mentioned in this embodiment is because the steel substrate 1 is located below the copper-containing molten metal 4. That is, along the thickness direction of the copper cladding 2 formed by the copper-containing molten metal 4, the closer to the steel substrate 1, the earlier the solidification time. In other words, the copper-steel junction is the position closest to the steel substrate 1. The copper-containing molten metal 4 at the copper-steel junction solidifies first, and the outer surface of the copper cladding 2 solidifies later.

[0047] In this embodiment, as Figure 2As shown, the heat insulation cover 5 is separated from the steel substrate 1. The heat insulation cover 5 is made of heat insulation material, and the thermal conductivity of the selected insulation material is less than or equal to the thermal conductivity of the steel substrate 1, thereby slowing down the heating rate of the steel substrate 1. The heat insulation material can be ceramic aerogel, nanofiber aerogel, aluminosilicate fiber cotton, etc. For example, silica-alumina composite ceramic aerogel (FR-SACA) is achieved by rearranging silica aerogel particles and mullite ceramic fibers using self-sacrificing polymers. It has high temperature resistance (1300–1600℃) and excellent heat insulation performance, forming a cross-interlocking reinforcing structure similar to a bird's nest, exhibiting excellent properties including low density, low thermal conductivity, and high reversible compressibility. Nanofiber aerogels can be ZrO2–Al2O3 nanofiber aerogel (ZrAlNFAs), etc.

[0048] In conventional cylinder casting, a copper block is placed on the upper surface of the steel substrate 1 of the cylinder, and both are heated together in a continuous furnace. The thermal conductivity of the copper alloy is 398 W / (m·K), while that of the steel substrate 1 is 45 W / (m·K). Their specific heat capacities are almost identical. During heating, the melting of the copper block is affected by the temperature of the steel substrate 1 in contact with it. The surface of the steel substrate 1 heats up faster than the copper block, causing the area where the copper block contacts the steel substrate 1 to melt first. This results in the copper liquid solidifying first on the side away from the steel substrate 1 during cooling, while the copper-steel interface side solidifies later, leading to shrinkage porosity and premature failure.

[0049] Therefore, in this embodiment, the heat insulation cover 5 and the air between the heat insulation cover 5 and the steel substrate 1 jointly block the continuous furnace from heating the steel substrate 1, making the heating rate of the steel substrate 1 less than the heating rate of the copper raw material. Figure 3 As shown, the heat insulation cover 5 can block the continuous high temperature environment inside the furnace from heating the steel substrate 1 and slow down the heating rate of the steel substrate 1. At the same time, the air between the heat insulation cover 5 and the steel substrate 1 can also isolate the hot atmosphere inside the heating furnace from the steel substrate 1. The thermal conductivity of air is 0.023 W / (m·K) and the specific heat capacity is 1030 J / (Kg·K), which is also a good heat insulation material. During the period when the copper raw material is heated and melted until it is completely deposited in the steel substrate 1, the temperature of the steel substrate 1 is kept below the liquidus temperature of the copper material.

[0050] The steel substrate 1, heat insulation cover 5, container 3, and copper raw material move together in the continuous furnace. The heating and heat preservation temperatures in the continuous furnace, as well as the moving speed of the continuous furnace, are controlled. In this embodiment, the continuous furnace operates at a certain melting and casting temperature T and a moving speed r to carry out corresponding heating, heat preservation, and cooling.

[0051] like Figure 2 As shown, container 3 is funnel-shaped, with an opening at the top to hold copper raw materials, and an opening at the bottom formed after passing through the heat insulation cover 5, allowing molten copper 4 to fall onto the steel substrate 1. In this embodiment, as... Figure 1 As shown, the steel substrate 1 is cylindrical, and one end of the copper coating 2 to be deposited has an annular groove. The copper raw material for preparing the copper coating 2 can be a cylindrical copper block.

[0052] After the copper-containing molten metal 4 falls onto the steel substrate 1, the copper-containing molten metal 4 in contact with the steel substrate 1 solidifies first, forming a temperature gradient with the temperature gradually increasing from the direction close to the steel substrate 1 to the direction far away from the steel substrate 1. Thus, it solidifies in the order from bottom to top, forming a high-density copper cladding layer 2. No additional human intervention is required during the transportation process, which meets the needs of continuous furnace production of bimetallic cylinders.

[0053] In this embodiment, the liquidus temperature of copper material refers to the melting temperature of copper raw material. When the steel substrate 1 is kept below the liquidus temperature of copper material, the copper-containing molten metal 4 in contact with the steel substrate 1 can be cooled and tend to solidify, thus establishing a trend of gradual solidification of the copper-containing molten metal 4 on the steel substrate 1 from the direction of contact with the steel substrate 1 to the direction away from the steel substrate 1.

[0054] The heat insulation effect of the heat insulation cover 5 reduces the heating rate of the steel substrate 1 surface, ensuring that the temperature of the steel substrate 1 remains below the liquidus temperature of the copper block. Furthermore, by controlling the temperature of the heating furnace and the conveyor belt speed, the copper raw material is fully melted and flows to cover the upper surface of the steel substrate 1. The copper-containing molten metal 4 flows through the funnel-shaped container 3 to the upper surface of the steel substrate 1. At this point, the temperature of the steel substrate 1 is lower than the liquidus temperature of the copper-containing molten metal 4, forming a temperature gradient that gradually decreases from top to bottom. The copper-containing molten metal 4 in contact with the steel substrate 1 solidifies preferentially, forming a solidification sequence from bottom to top.

[0055] Once the temperature of all the copper-containing molten metal 4 that falls onto the steel substrate 1 is lower than the liquid phase temperature of copper, all the copper-containing molten metal 4 that can form the copper coating 2 will completely cover the steel substrate 1, forming the required deposition state. The overall state has been fixed, and then it is sent to the cooling section of the continuous furnace for further cooling.

[0056] By wrapping the steel substrate 1 with heat-insulating material, the heating rate of the steel substrate 1 during the heating process in the continuous furnace is significantly lower than that of the copper raw material. Finally, at the same ambient temperature, the copper raw material melts, while the temperature of the steel substrate 1 remains lower than the liquidus temperature of the copper material. This allows the copper-containing molten metal 4 to solidify in a bottom-up sequence on the steel substrate 1.

[0057] The steel matrix 1 is made of alloy steel, specifically 42CrMoS4, with the following chemical composition: C 0.40-0.45%, Si≤0.40%, Mn 0.60-0.90%, P≤0.025%, S 0.010-0.018%, Cr 0.90-1.20%, Mo 0.15-0.30%, Cu≤0.20%, Ni≤0.30%, and the microstructure is pearlite + ferrite. The melting and casting temperature in the continuous furnace is 1080℃≤T≤1120℃, and the conveyor belt speed of the continuous furnace is 80mm / min≤r≤115mm / min.

[0058] In this embodiment, the steel substrate 1 has an external dimension of Φ108*98mm, the number of copper blocks is 4, the size is Φ35*20, the heat insulation material is 45# steel, the heat insulation cover 5 has a size of Φ170*130mm, the melting and casting temperature is T=1080℃, and the speed of the continuous furnace conveyor belt is r=85mm / min.

[0059] The temperature curves of the copper ingot and the steel portion near the copper layer during the casting process are as follows: Figure 3 As shown, when the temperature of the copper block reaches 1080℃, the temperature of the steel substrate 1 is only 790℃. No shrinkage defects were found in the copper cladding 2 of the cast cylinder body. The density of the copper cladding 2 is higher than that of conventional casting. The metallographic structure of the copper cladding 2 is as follows... Figure 4 As shown. Figure 5 The metallographic structure of the copper cladding layer of the cylinder block produced by conventional casting process.

[0060] In addition, when using the traditional casting method, a temperature gradient with a gradual increase in temperature from top to bottom is formed in the copper-containing molten metal 4. This causes the copper-containing molten metal 4 to solidify in a top-down direction when cooling. This not only leads to a large shrinkage porosity at the copper-steel interface, but also, when using a copper cladding layer 2 made of tin-lead bronze, under this solidification direction, the second phase Pb phase in the tin-lead bronze will tend to aggregate at the copper-steel composite interface under the influence of temperature gradient and surface tension, further weakening the interfacial bonding force.

[0061] In this embodiment, the copper alloy used as the copper raw material is tin-lead bronze, CuSn10Pb10, with the following chemical composition (mass percentage): Sn 7.25-7.85%, Pb 14.1-17.26%, Ni 1.24-1.86%, Zn 0.01-0.05%, P less than 0.1%, and the metallographic structure is α-Cu+spherical Pb.

[0062] The second phase, Pb, tends to aggregate in high-temperature regions under the influence of a temperature gradient. In this invention, the temperature gradient of the copper-containing molten metal 4 increases from bottom to top, which enables the Pb phase to be uniformly dispersed and slows down its aggregation at the copper-steel composite interface. At the same time, since the upper part is at a higher temperature, i.e., the upper part is in a liquid state and the lower copper-steel composite interface is in a semi-solid or solid state, the Pb phase can aggregate in the liquid region under the influence of surface tension, thereby achieving uniform dispersion and ensuring the interfacial bonding force.

[0063] Such as 4 and Figure 5 As shown, compared with the two, the Pb phase in the cast copper cladding 2 in this embodiment is uniformly distributed and has no network distribution, which greatly reduces the influence of Pb on the copper matrix and interface strength.

[0064] Example 2

[0065] In another typical embodiment of the present invention, such as Figures 1-4 As shown, a tooling for preparing a continuous bimetallic cylinder block is presented.

[0066] The tooling for preparing a continuous furnace bimetallic cylinder body, as described in Example 1, includes a continuous furnace, a heat shield 5, and a container 3.

[0067] The continuous furnace includes a heating section, a heat preservation section, and a cooling section arranged sequentially in the conveying direction. During melting and casting, the heating section and the heat preservation section can provide a melting and casting temperature of 1080℃≤T≤1120℃.

[0068] The heat shield 5 has a cavity for housing the steel substrate 1; the main body of the container 3 is located outside the heat shield 5 and is used to hold the copper raw materials for making the copper cladding 2. The outlet of the container 3 extends through the heat shield 5 into the cavity.

[0069] In this embodiment, the heat insulation cover 5 is a shell structure with an opening at the bottom and an opening at the top. The bottom opening of the heat insulation cover 5 forms a cavity with the conveyor belt of the continuous furnace, and the top opening of the heat insulation cover 5 is used for the outlet of the container 3 to pass through. The container 3 is funnel-shaped, with a conical groove at one end and a drain pipe at the other end. The groove area is located outside the heat insulation cover 5, and one end of the drain pipe is connected to the bottom of the groove, while the other end passes through the heat insulation cover 5 to form the outlet of the container 3.

[0070] The heat insulation cover 5 is made of 45# steel. The heat insulation cover 5 has a size of Φ170*130mm and can be covered over the steel base 1. The outer dimensions of the steel base 1 are Φ108*98mm. The end face is provided with an annular groove to accommodate the copper-containing molten metal 4. The continuous furnace provides a melting and casting temperature of T=1080℃ and the speed of the continuous furnace conveyor belt is r=85mm / min.

[0071] Example 3

[0072] In another typical embodiment of the present invention, such as Figure 1 As shown, a hydraulic cylinder is presented.

[0073] In this embodiment, the cylinder body of the hydraulic cylinder is manufactured using the same process as the continuous furnace bimetallic cylinder body fabrication process described in Example 1. Figure 1 As shown, after the cylinder body is manufactured, the corresponding hydraulic cylinder components are assembled to obtain the hydraulic cylinder.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for preparing a bimetallic cylinder body for a continuous furnace, characterized in that, include: Fabrication of the steel substrate; The steel substrate is placed on the continuous furnace conveyor belt and covered with a heat insulation cover, and a container is arranged on the heat insulation cover. The heat insulation cover is made of heat insulation materials, including ceramic aerogel, nanofiber aerogel, and aluminum silicate fiber cotton. The heat insulation cover is separate from the steel substrate. The heat insulation cover and the air between it and the steel substrate together block the continuous furnace from heating the steel substrate, so that the temperature of the steel substrate is kept below the liquidus temperature of the copper material. The copper raw materials for making the copper cladding are placed in a container and fed into a continuous furnace for heating. The container is funnel-shaped, with an opening at the top for placing copper raw materials, and an opening at the bottom after passing through a heat insulation cover, allowing copper-containing molten metal to fall onto the steel substrate. The copper raw material is heated to a temperature above the liquidus temperature of copper until it melts into a copper-containing metal melt. The copper-containing molten metal falls through the heat insulation cover onto the steel substrate. The copper-containing molten metal in contact with the steel substrate solidifies first, forming a temperature gradient that gradually increases in temperature from the direction of approaching the steel substrate to the direction of away from the steel substrate. The copper-containing molten metal solidifies on the steel substrate in a bottom-up order, forming a copper cladding layer on the steel substrate. After the temperature of all the copper-containing molten metal that has fallen onto the steel substrate is lower than the liquidus temperature of copper, the steel substrate and the copper cladding layer are sent into the cooling section of the continuous furnace to obtain the cylinder body.

2. The manufacturing process of the continuous furnace bimetallic cylinder as described in claim 1, characterized in that, The steel substrate, heat insulation cover, container, and copper raw material move together within the continuous furnace.

3. A tooling for preparing a bimetallic cylinder body for a continuous furnace, characterized in that, The tooling for preparing a continuous furnace bimetallic cylinder body according to any one of claims 1-2 includes a continuous furnace, a heat insulation cover, and a container. The continuous furnace includes a heating section, a heat preservation section, and a cooling section that are sequentially distributed along the conveying direction; The heat insulation cover has an internal cavity for housing the steel substrate; The container, with its main body located outside the heat shield, is used to hold copper raw materials for making copper cladding. The container's outlet extends through the heat shield into the cavity.

4. The tooling for preparing the bimetallic cylinder of the continuous furnace as described in claim 3, characterized in that, The heat insulation cover is a shell structure with an opening at the bottom and a hole at the top. The bottom opening of the heat insulation cover forms a cavity with the conveyor belt of the continuous furnace, and the top opening of the heat insulation cover is used for the outlet of the container to pass through.

5. The tooling for preparing the bimetallic cylinder body of the continuous furnace as described in claim 3, characterized in that, The container is funnel-shaped, with a conical groove at one end and a drain pipe at the other end. The groove area is located outside the heat insulation cover. One end of the drain pipe is connected to the bottom of the groove, and the other end passes through the heat insulation cover to form the outlet of the container.

6. A hydraulic cylinder, characterized in that, It is manufactured using the preparation process of the continuous furnace bimetallic cylinder as described in any one of claims 1-2.

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