A copper-steel dual alloy component cast shell and a method of manufacturing the same

Abstract

The application discloses a copper-steel double-alloy part casting mold shell and a preparation method thereof. The preparation method comprises the following steps: designing a melting mold structure according to the specification of a target copper-steel double-alloy part, then designing and manufacturing a metal mold based on the melting mold structure, coating and hanging multiple layers of ceramic materials and refractory materials on the outer surface of the melting mold, drying the melting mold, and removing the wax material by high-temperature water vapor to obtain a casting mold shell; then, a steel core and oxygen-free copper raw material are loaded into the casting mold shell, and the casting mold shell is sealed to obtain a part mold shell; then, the part mold shell is placed into a vacuum heating furnace and heated to 1150 DEG C to 1180 DEG C, so that the oxygen-free copper is melted and wrapped around the steel core; finally, the ceramic casting mold shell is knocked to pieces, and a double-metal casting part is obtained. The application has low requirements for the material of the metal mold, is convenient to process, has low requirements for the heating temperature because the casting mold shell directly participates in heating during the forming stage, has low production cost and maintenance cost, reduces the process control difficulty in the production process, and ensures the quality of the final product.

Description

Technical Field

[0001] This invention belongs to the field of investment casting technology, specifically relating to a copper-steel bialloy casting mold shell and its preparation method. Background Technology

[0002] In recent years, with increasingly stringent requirements for the comprehensive performance of engineering materials, components made from single-metal materials are finding it increasingly difficult to meet their all-around performance needs. Furthermore, the gradual scarcity of precious metal resources has led to the growing industrial adoption and application of bimetallic materials. While maintaining the original properties of each metal, bimetallic materials offer significantly improved overall performance, and their manufacturing processes are receiving increasing attention.

[0003] Taking copper-steel bimetallic components used in aerospace, high-end medical, and automotive fields as an example, existing technologies typically employ pressure casting. This process involves fixing a steel core within a metal mold cavity, then injecting molten copper into the cavity under pressure after mold closing. The copper then encapsulates the steel core and cools and solidifies, forming a bimetallic casting. While pressure casting offers high production efficiency, it suffers from the following problems: Firstly, to ensure the molding quality of the product, oxygen-free copper needs to be heated to a high temperature (1230℃) before die casting. However, the high degree of superheat places high demands on the mold material. Therefore, nickel-based high-temperature alloys are usually used to make metal molds. In addition to the high material cost, the processing difficulty is also higher than that of ordinary mold steel. Secondly, die casting molds need to be assembled on die casting machines for production operations, and there are many control parameters, each of which has a significant impact on the final metallurgical quality of the product. Third, in addition to reducing the service life of the mold, the high degree of overheating will also cause the copper liquid to absorb O and H in the air at high temperature, reducing the conductivity of copper and thus reducing the final performance of the component. Fourth, due to the high degree of superheat, the process of heating copper will increase energy consumption.

[0004] In addition, in order to effectively avoid the absorption of O and H during the melting process of copper liquid and improve the conductivity of copper, thereby ensuring the performance of the final copper-steel bialloy components, some manufacturers use vacuum gravity casting. However, this method has a complex metal mold sealing structure, which is difficult to manufacture, install and maintain, resulting in higher costs. It also has the problems of poor air permeability of metal molds (the cavity cannot be effectively vented during pouring, which can easily lead to insufficient filling), difficulty in controlling temperature parameters, and difficulty in handling and opening the high-temperature mold after pouring, ultimately resulting in a low product qualification rate.

[0005] In view of this, this invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a copper-steel bialloy casting mold shell and its preparation method. This invention produces a corresponding ceramic casting mold shell according to the specifications of the target copper-steel bialloy component to be processed. The ceramic casting mold shell is a one-time casting mold, and there is no need to open the mold immediately after casting. After the casting mold has cooled sufficiently, it is only necessary to break and remove the ceramic casting mold shell to obtain the corresponding casting, which ensures the product qualification rate. At the same time, the metal mold used to prepare the ceramic casting mold shell can be reused, reducing production costs.

[0007] The objective of this invention is achieved through the following technical solution: On one hand, the present invention provides a method for preparing a copper-steel bialloy component, comprising the following steps: Step 1: Making a metal mold Design the structure of the upper and lower mold according to the specifications of the target copper-steel bialloy component, and then design and manufacture the corresponding metal molds according to the structure of the upper and lower molds. Step 2: Making the casting mold assembly Based on the upper and lower mold design in step one, and using medium-temperature casting wax material under set process parameters, the upper and lower molds are made using the metal mold obtained in step one. Then, the upper and lower molds are filled with wax liquid and the metal connecting rod is fixed to obtain the upper mold assembly and the lower mold assembly. Finally, the upper and lower mold assemblies are cleaned and dried. Step 3: Making the casting mold shell First, ceramic slurry and refractory material are coated on the outer surfaces of the upper and lower mold modules in step two. After the ceramic slurry dries and hardens, the initial upper mold shell and the initial lower mold shell are formed. Then, the wax mold is removed and the metal connecting rod is taken out. Then, the initial upper mold shell and the initial lower mold shell are checked to see if they are qualified. After confirming that they are qualified, the initial upper mold shell and the initial lower mold shell are fired at a set temperature to form a casting shell composed of the upper mold shell and the lower mold shell. Step 4: Fabrication of copper-steel bialloy components First, install the steel core of the target copper-steel bialloy component into the lower mold shell obtained in step three. Then, place the oxygen-free copper raw material that makes up the target copper-steel bialloy component onto the upper end of the steel core. Next, assemble and seal the upper and lower mold shells obtained in step three. Finally, vacuum heat the entire casting shell containing the copper-steel bialloy component raw material. Utilize the melting point difference between the oxygen-free copper raw material and the steel core to pour the molten oxygen-free copper between the casting shell cavity and the steel core. After the entire casting shell cools down, break the casting shell to obtain the target copper-steel bialloy component.

[0008] Furthermore, in step two, 162 wax material is used to create the upper and lower mold casting patterns on a 16T hydraulic wax injection machine.

[0009] Furthermore, the process parameters for making the upper mold in step two are as follows: wax tank temperature 58±5℃, cooling tank temperature 58±5℃, cooling time 30s~50s, and wax injection pressure 5Kg / cm². 2 ~15Kg / cm 2 Wax injection flow rate 20%, wax injection time 15s~25s, nozzle pressure holding time 10s~20s; The process parameters for the lower mold casting process are: wax tank temperature 58±5℃, cooling tank temperature 58±5℃, cooling time 40s~60s, and wax injection pressure 10Kg / cm³. 2 ~18Kg / cm 2 The wax injection flow rate is 20%, the wax injection time is 20s to 30s, and the nozzle pressure holding time is 15s to 25s.

[0010] Furthermore, in step two, when the wax liquid fills the upper mold and lower mold and fixes the metal connecting rod, the temperature of the wax liquid is 110℃~130℃, and the pressed upper mold and lower mold should be allowed to cool down for more than 2 hours before filling with wax liquid.

[0011] Furthermore, in step three, when making the casting shell, the order of coating the lower mold casting slurry and refractory material is as follows: surface layer → transition layer → reinforcing layer → sealing layer; The surface slurry consists of silica sol, zircon powder, penetrant, and defoamer; the refractory material (sand) is 80-120 mesh zircon; the drying time should be greater than 8 hours; the coating layer consists of 2 layers; the drying room temperature is 19℃-23℃; and the drying room humidity is 50%-70%. The transition layer slurry consists of silica sol and refractory powder, and the refractory material (sand) is 30-60 mesh refractory sand. The drying time should be greater than 6 hours, the coating layer is 1 layer, the drying room temperature is 19℃-23℃, and the drying room humidity is 50%-70%. The reinforcing layer slurry consists of silica sol and refractory powder, and the refractory material (sand) is 30-60 mesh refractory sand. The drying time should be greater than 6 hours, the coating layer should be 3 layers, the drying room temperature should be 19℃-23℃, and the drying room humidity should be 30%-60%. The sealing layer slurry consists of silica sol and styrene powder. The drying time should be greater than 12 hours. The coating layer is 1 layer. The drying room temperature is 19℃~23℃ and the drying room humidity is 30%~60%.

[0012] Furthermore, the wax casting removal in step three is carried out in a high-pressure steam dewaxing kettle, as detailed below: The parameters for removing the wax from the initial upper mold shell are: steam pressure 0.6MPa~0.8MPa, dewaxing temperature 165℃~175℃, and dewaxing time 10min~20min; The initial parameters for removing the wax from the lower mold shell are: steam pressure 0.6MPa~0.8MPa, dewaxing temperature 165℃~175℃, and dewaxing time 15min~25min.

[0013] Furthermore, before firing the initial upper and lower model shells in step three, the dewaxed initial upper and lower model shells should be allowed to dry naturally for more than 24 hours. In step three, when the initial upper and lower mold shells are fired, the temperature is set to 800℃~900℃. After holding at this temperature for 1h~2h, the temperature is cooled to below 100℃ in the furnace. The shells are then removed and cooled to room temperature to obtain the casting shell.

[0014] Furthermore, in step four, before preparing the copper-steel bialloy component, the cavities of the upper and lower mold shells are cleaned, and after cleaning, they are naturally dried for more than 24 hours or dried in a furnace at 100℃~150℃ for more than 4 hours.

[0015] Furthermore, after the upper and lower model shells are assembled, refractory putty is used to seal the gaps at the junction of the dividing line. After sealing, the casting shell is naturally dried for 24 hours and then vacuum heated at a temperature of 1150℃~1180℃.

[0016] On the other hand, the present invention provides a copper-steel bialloy casting shell, which is prepared based on the above-mentioned preparation method. The casting shell includes an upper mold shell and a lower mold shell that cooperate with each other, and both the upper mold shell and the lower mold shell are ceramic shells.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention first fabricates a corresponding metal mold based on the specifications of the target copper-steel bialloy component. Then, using medium-temperature casting wax as raw material, a wax casting mold assembly is created based on the metal mold. A ceramic casting shell is then fabricated using the wax casting mold assembly. The steel core and oxygen-free copper raw material from the target copper-steel bialloy component are then installed inside the ceramic casting shell. The ceramic casting shell with the copper-steel bialloy component raw material installed is then sealed. Finally, the entire casting shell is vacuum-heated. Utilizing the melting point difference between the oxygen-free copper raw material and the steel core, the molten oxygen-free copper is poured between the casting shell cavity and the steel core. After cooling, simply breaking the ceramic casting shell yields a high-quality copper-steel bialloy casting. Compared to existing die-casting processes, this invention has the following advantages: First, this invention reduces the requirements for the material and processing difficulty of the metal mold. The metal mold of this invention can be made of ordinary mold steel or forged aluminum alloy, which is easier to process than nickel-based high-temperature alloy mold. This is because in this invention, the metal mold is only used to make the casting mold assembly and does not come into direct contact with the heated copper-steel bialloy component raw material. Secondly, this invention only requires controlling the vacuum degree, temperature and holding time during oxygen-free copper casting, thus reducing the difficulty of process control in the production process; Third, the casting shell of this invention is made of ceramic material, so it can be heated as a whole with the raw materials. Therefore, it does not need to be heated to an excessively high temperature, that is, it only needs to be heated to 1150℃~1180℃ (no high superheat is required), which saves energy and cost. Fourth, this invention, combined with vacuum casting, reduces the probability of oxygen and hydrogen accumulation in oxygen-free copper, thereby improving the conductivity of copper. Fifth, the ceramic casting shell of this invention is a one-time casting mold. After pouring, there is no need to open the mold immediately. After sufficient cooling, the target copper-steel bialloy part can be obtained simply by breaking and removing the ceramic casting shell, which reduces the labor intensity of workers, improves the permeability of the casting mold, and increases the qualification rate of the casting products. Attached Figure Description

[0018] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the preparation method of the copper-steel bialloy component of the present invention; Figure 2 This is a schematic diagram of the upper mold casting structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the lower mold casting structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the upper casting mold module structure in an embodiment of the present invention; Figure 5 This is a schematic diagram of the lower casting mold module structure in an embodiment of the present invention; Figure 6 This is a schematic diagram of the casting shell in use in an embodiment of the present invention; Wherein: 1 is the upper mold casting mold; 2 is the lower mold casting mold; 3 is the wax material; 4 is the metal connecting rod (connecting the shell-making robotic arm); 5 is the dividing line; 6 is the upper model shell; 7 is the lower model shell; 8 is the refractory putty; 9 is the steel core; 10 is the oxygen-free copper raw material. Detailed Implementation

[0021] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses consistent with some aspects of the invention as detailed in the appended claims.

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] Please see Figure 1 This invention provides a method for preparing copper-steel bialloy components, specifically including the following steps: Step 1: Making a metal mold Design the structure of the upper and lower mold according to the specifications of the target copper-steel bialloy component, and then design and manufacture the corresponding metal molds according to the structure of the upper and lower molds. Step 2: Making the casting mold assembly Based on the upper and lower mold design in step one, and using medium-temperature casting wax material under set process parameters, the upper and lower molds are made using the metal mold obtained in step one. Then, the upper and lower molds are filled with wax liquid and the metal connecting rod is fixed to obtain the upper mold assembly and the lower mold assembly. Finally, the upper and lower mold assemblies are cleaned and dried. Specifically, the upper and lower mold casting molds are made using 162 wax material on a 16T hydraulic wax injection machine. The process parameters are shown in Table 1 below. After the casting mold is pressed, it is cooled for more than 2 hours. The casting mold is then filled with 162 medium-temperature wax liquid at 110℃~130℃ and the metal connecting rod is fixed to form the upper and lower casting mold groups. The casting mold groups are then immersed in water-based wax mold cleaning agent and shaken up and down 3 to 4 times to clean the release agent on the surface of the casting mold groups. The total cleaning time is 3s to 5s. Finally, the casting mold groups are immersed in running clean water to clean the residual degreasing agent on the surface and air-dried naturally.

[0024] Table 1. Investment casting process parameters Step 3: Making the casting mold shell First, ceramic slurry and refractory material are coated on the outer surfaces of the upper and lower mold modules in step two. After the ceramic slurry dries and hardens, the initial upper mold shell and the initial lower mold shell are formed. Then, the wax mold is removed and the metal connecting rod is taken out. Then, the initial upper mold shell and the initial lower mold shell are checked to see if they are qualified. After confirming that they are qualified, the initial upper mold shell and the initial lower mold shell are fired at a set temperature to form a casting shell composed of the upper mold shell and the lower mold shell. Specifically, the initial shell is made on the fully automated shell-making line according to the shell-making process in Table 2. When making the initial shell, the order of coating the slurry and refractory material is as follows: surface layer → transition layer → reinforcing layer → sealing layer. After each layer is coated, the slurry on the dividing line between the upper and lower molds is scraped off with a blade to ensure that the initial shell is divided into two parts by the dividing line after dewaxing. The part on the side of the metal connecting rod is the excess shell and should be discarded. During the scraping process, care should be taken to minimize damage to the casting mold and not to damage the initial shell in other positions.

[0025] Table 2 Shell making process parameters Remove the wax material in a high-pressure steam dewaxing kettle and take out the metal connecting rod; check whether there are cracks on the surface of the initial shell and whether the initial shell has fallen off the inner surface of the cavity. If there are no cracks or falling off, the initial shell is qualified; otherwise, the initial shell is unqualified. After dewaxing, let it dry naturally for more than 24 hours, then put the initial shell into an electric heating furnace at room temperature; close the furnace door, set the heating temperature to 800℃~900℃, hold it for 1~2 hours, and then cool it down to below 100℃ with the furnace. Take it out to obtain the casting shell.

[0026] Step 4: Fabrication of copper-steel bialloy components First, install the steel core of the target copper-steel bialloy component into the lower mold shell obtained in step three. Then, place the oxygen-free copper raw material that makes up the target copper-steel bialloy component onto the upper end of the steel core. Next, assemble and seal the upper and lower mold shells obtained in step three. Finally, vacuum heat the entire casting shell containing the copper-steel bialloy component raw material. Utilize the melting point difference between the oxygen-free copper raw material and the steel core to pour the molten oxygen-free copper between the casting shell cavity and the steel core. After the entire casting shell cools down, break the casting shell to obtain the target copper-steel bialloy component.

[0027] Specifically, before preparing the copper-steel bialloy components, the cavities of the upper and lower mold shells are cleaned. After cleaning, they are naturally dried for more than 24 hours or dried in a furnace at 100℃~150℃ for more than 4 hours. During assembly, the steel core is first placed into the lower mold shell, then the oxygen-free copper raw material is placed on the upper end of the steel core, and finally the upper mold shell is covered. During the assembly process, care is taken to prevent foreign objects from falling into the cavity. After assembly, the casting shell is always placed facing upwards (upper mold on top, lower mold on bottom), and shaking or vibration of the casting shell is avoided. After the upper and lower mold shells are assembled, refractory mortar is used to seal the gaps at the joint. After sealing, the casting shell is naturally dried for 24 hours, and then vacuum heated at a temperature of 1150℃~1180℃.

[0028] To further verify the effectiveness of the preparation method of the present invention, the inventors conducted the following specific experiments: Example

[0029] Taking the preparation of a copper-steel bialloy casting for a certain medical device as an example, the specific preparation process is as follows: 1) Design the structure of the upper and lower investment molds based on the structure and dimensions of the copper-steel bialloy casting, specifically as follows: Figure 2 , 3 As shown; 2) Design and manufacture corresponding metal molds (including upper and lower molds) according to the structure of the upper and lower molds. 3) Prepare the investment mold (including the upper investment mold and the lower investment mold) using 162 wax material (casting medium temperature wax material) on a 16T hydraulic wax injection machine. The process parameters for the upper mold casting process are as follows: wax tank temperature 58℃, cooling tank temperature 58℃, cooling time 40s, and wax injection pressure 10Kg / cm³. 2 The wax injection flow rate is 20%, the wax injection time is 20 seconds, and the nozzle holding time is 15 seconds. The process parameters for the lower mold casting are: wax tank temperature 58℃, cooling tank temperature 58℃, cooling time 50 seconds, and wax injection pressure 14 kg / cm². 2 Wax injection flow rate 20%, wax injection time 25s, nozzle pressure holding time 20s; 4) After the investment mold has been pressed and cooled for 4 hours, the investment mold is filled with 120°C medium-temperature wax liquid at 162°C, and the metal connecting rod 4 is fixed to obtain the upper investment mold module and the lower investment mold module, as detailed below. Figure 4 , 5 As shown; 5) Immerse the mold assembly (upper mold assembly and lower mold assembly) in water-based wax mold cleaner and shake it up and down 3 times to clean the mold release agent on the surface of the mold, with a total cleaning time of 4 seconds; then immediately immerse the mold assembly in running water to clean the residual degreasing agent on its surface and let it air dry naturally. 6) Produce the initial shell (including the initial upper mold shell and the initial lower mold shell) on the fully automated shell-making line according to the following shell-making process. Immediately after each layer of coating is applied, use a blade to remove the coating. Figure 4 , 5 Remove the adhesive and refractory material on the boundary line 5 shown. During the scraping process, minimize damage to the casting mold and avoid damaging other parts of the shell. The shell-making process involves coating the outer surfaces of the upper and lower investment mold modules with ceramic slurry and refractory material. The coating sequence is: surface layer → transition layer → reinforcing layer → sealing layer. Specifically, the surface layer slurry consists of silica sol + zircon powder + penetrant + defoamer, with 100-mesh zircon sand (refractory material) applied. The drying time is 10 hours, with two coating layers. The drying room temperature is 21℃, and the humidity is 60%. The transition layer slurry consists of silica sol + zircon powder, with 100-mesh zircon sand (refractory material) applied. The first layer of refractory slurry consists of 50-mesh refractory sand, dried for 8 hours, with one coating layer, at a drying room temperature of 22℃ and a drying room humidity of 65%. The second layer of refractory slurry consists of silica sol and refractory powder, with 40-mesh refractory sand, dried for 8 hours, with three coating layers, at a drying room temperature of 23℃ and a drying room humidity of 40%. The third layer of refractory slurry consists of silica sol and refractory powder, dried for 16 hours, with one coating layer, at a drying room temperature of 19℃ and a drying room humidity of 30%. 7) Remove the wax material in the high-pressure steam dewaxing kettle according to the following process parameters, and take out the metal connecting rod; The process parameters for the initial upper mold shell during wax removal are: steam pressure 0.67 MPa, dewaxing temperature 170℃, and dewaxing time 15 min; the parameters for the initial lower mold shell during wax removal are: steam pressure 0.7 MPa, dewaxing temperature 163℃, and dewaxing time 20 min. 8) Check whether there are cracks on the surface of the initial shell and whether the shell has fallen off the inner surface of the cavity. If there are no cracks or falling off, the initial shell is qualified; otherwise, the initial shell is unqualified. 9) After the initial shell is dewaxed, it is naturally dried for 14 hours, and then the initial shell is put into an electric heating furnace at room temperature. 10) Close the furnace door, set the heating temperature to 850℃, hold for 1.5 hours, then cool it down to 30℃ with the furnace and remove it to obtain the casting shell; 11) After cooling the casting shell to room temperature, rinse the cavity of the shell with running water 5 times. 12) After cleaning, the casting shell is dried in a furnace at 120℃ for 5 hours, then removed and placed at room temperature; 13) According to Figure 6 The casting mold shell is assembled in steps as shown. Specifically, first, the steel core 9 is placed into the lower mold shell 6, then the oxygen-free copper raw material 10 is placed on top of the steel core 6, and finally the upper mold shell 7 is placed on top. During the assembly process, care should be taken to prevent foreign objects from falling into the cavity. After assembly, the mold shell should always be placed facing upwards (i.e., the upper mold is on top and the lower mold is on the bottom), and shaking or vibration of the mold shell should be avoided. 14) Seal the gaps between the upper and lower mold shells with refractory putty 8, and allow the casting shell to dry naturally for 24 hours after sealing. 15) Place the casting shell containing the raw materials into a vacuum heating furnace and heat it to 1180°C so that the molten oxygen-free copper is poured between the casting shell cavity and the steel core. 16) After the casting shell has cooled to room temperature, the ceramic casting shell is broken to obtain the target copper-steel bialloy casting.

[0030] Finally, after testing, the chemical composition, conductivity, and dimensions of the copper-steel bialloy parts prepared using the above steps all met the drawings and user requirements. After installation and testing, their performance was better than or comparable to that of the copper-steel bialloy parts obtained by die casting.

[0031] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0032] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a copper-steel bialloy component, characterized in that, Includes the following steps: Step 1: Making a metal mold Design the structure of the upper and lower molds according to the specifications of the target copper-steel bialloy component, and then design and manufacture the corresponding metal molds according to the structure of the upper and lower molds. Step 2: Making the casting mold assembly Based on the upper and lower mold design in step one, and using casting medium-temperature wax material under set process parameters, the upper and lower molds are made using the metal mold obtained in step one. Then, the upper and lower molds are filled with wax liquid and the metal connecting rod is fixed to obtain the upper mold assembly and the lower mold assembly. Finally, the upper and lower mold assemblies are cleaned and dried. Step 3: Making the casting mold shell First, ceramic slurry and refractory material are coated on the outer surfaces of the upper and lower mold modules in step two. After the ceramic slurry dries and hardens, the initial upper mold shell and the initial lower mold shell are formed. Then, the wax mold is removed and the metal connecting rod is taken out. Then, the initial upper mold shell and the initial lower mold shell are checked to see if they are qualified. After confirming that they are qualified, the initial upper mold shell and the initial lower mold shell are fired at a set temperature to form a casting shell composed of the upper mold shell and the lower mold shell. Step 4: Fabrication of copper-steel bialloy components First, install the steel core of the target copper-steel bialloy component into the lower mold shell obtained in step three. Then, place the oxygen-free copper raw material that makes up the target copper-steel bialloy component onto the upper end of the steel core. Next, assemble and seal the upper and lower mold shells obtained in step three. Finally, vacuum heat the entire casting shell containing the copper-steel bialloy component raw material. Utilize the melting point difference between the oxygen-free copper raw material and the steel core to pour the molten oxygen-free copper between the casting shell cavity and the steel core. After the entire casting shell cools down, break the casting shell to obtain the target copper-steel bialloy component.

2. The method for preparing the copper-steel bialloy component according to claim 1, characterized in that, In step two, 162 wax material is used, and upper and lower mold castings are made on a 16T hydraulic wax injection machine.

3. The method for preparing the copper-steel bialloy component according to claim 2, characterized in that, The process parameters for making the upper mold in step two are as follows: wax tank temperature 58±5℃, cooling tank temperature 58±5℃, cooling time 30s~50s, and wax injection pressure 5Kg / cm. 2 ~15Kg / cm 2 Wax injection flow rate 20%, wax injection time 15s~25s, nozzle pressure holding time 10s~20s; The process parameters for the lower mold casting process are: wax tank temperature 58±5℃, cooling tank temperature 58±5℃, cooling time 40s~60s, and wax injection pressure 10Kg / cm³. 2 ~18Kg / cm 2 The wax injection flow rate is 20%, the wax injection time is 20s to 30s, and the nozzle pressure holding time is 15s to 25s.

4. The method for preparing the copper-steel bialloy component according to claim 1, characterized in that, In step two, when the wax liquid fills the upper and lower mold casting molds and fixes the metal connecting rod, the temperature of the wax liquid is set to 110℃~130℃, and the pressed upper and lower mold casting molds should be allowed to cool down for more than 2 hours before filling with wax liquid.

5. The method for preparing the copper-steel bialloy component according to claim 1, characterized in that, In step three, when making the casting shell, the order of coating ceramic slurry and refractory material is as follows: surface layer → transition layer → reinforcement layer → sealing layer. The surface slurry consists of silica sol, zircon powder, penetrant, and defoamer; the refractory material is 80-120 mesh zircon; the drying time should be greater than 8 hours; the coating layer consists of 2 layers; the drying room temperature is 19℃-23℃; and the drying room humidity is 50%-70%. The transition layer slurry consists of silica sol and slag powder, the refractory material is 30-60 mesh slag sand, the drying time should be greater than 6 hours, the coating layer is 1 layer, the drying room temperature is 19℃-23℃, and the drying room humidity is 50%-70%. The reinforcing layer slurry consists of silica sol and slag powder, the refractory material is 30-60 mesh slag sand, the drying time should be greater than 6 hours, the coating layer is 3 layers, the drying room temperature is 19℃-23℃, and the drying room humidity is 30%-60%. The sealing layer slurry consists of silica sol and styrene powder. The drying time should be greater than 12 hours. The coating layer is 1 layer. The drying room temperature is 19℃~23℃ and the drying room humidity is 30%~60%.

6. The method for preparing the copper-steel bialloy component according to claim 1, characterized in that, In step three, the wax casting process is carried out in a high-pressure steam dewaxing kettle, as detailed below: The parameters for removing the wax from the initial upper mold shell are: steam pressure 0.6MPa~0.8MPa, dewaxing temperature 165℃~175℃, and dewaxing time 10min~20min; The initial parameters for removing the wax from the lower mold shell are: steam pressure 0.6MPa~0.8MPa, dewaxing temperature 165℃~175℃, and dewaxing time 15min~25min.

7. The method for preparing the copper-steel bialloy component according to claim 1, characterized in that, Before firing the initial upper and lower model shells in step three, the dewaxed initial upper and lower model shells should be allowed to dry naturally for more than 24 hours. In step three, when the initial upper and lower mold shells are fired, the temperature is set to 800℃~900℃. After holding at this temperature for 1h~2h, the temperature is cooled to below 100℃ in the furnace. The shells are then removed and cooled to room temperature to obtain the casting shell.

8. The method for preparing the copper-steel bialloy component according to claim 1, characterized in that, In step four, before preparing the copper-steel bialloy component, the cavities of the upper and lower mold shells are cleaned. After cleaning, they are naturally dried for more than 24 hours or dried in a furnace at 100℃~150℃ for more than 4 hours.

9. The method for preparing the copper-steel bialloy component according to claim 1, characterized in that, After the upper and lower model shells are assembled, refractory putty is used to seal the gaps at the joint of the dividing line. After sealing, the casting shell is naturally dried for 24 hours and then vacuum heated at a temperature of 1150℃~1180℃.

10. A copper-steel bialloy casting mold shell, characterized in that, The casting shell is prepared by any one of the preparation methods in claims 1 to 9. The casting shell includes an upper model shell and a lower model shell that fit together, and both the upper model shell and the lower model shell are ceramic shells.

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