An apparatus and method for controlling the deformation and solidification of a high-speed railway box body in investment casting

Abstract

The present invention discloses a device and a method for controlling the deformation and solidification of a high-speed rail box body in investment casting. By using a device for controlling the deformation and solidification of a high-speed rail box body in investment casting to perform investment casting on the high-speed rail box body, its production method includes the following steps: mold making combination, shell making, wax removal, roasting, melting, casting, shell cleaning, and heat treatment. The device for controlling the deformation and solidification of a high-speed rail box body in investment casting includes a box body. A pouring system is installed on the box body, and the left side of the pouring system is a pouring tube. At the same time, a carbon dioxide flow channel is provided on the back of the box body. A left channel tube is installed on the left side of the carbon dioxide flow channel, and a right channel tube is installed on the right side of the carbon dioxide flow channel. A heat treatment tooling is installed on the front of the box body; using carbon dioxide as a cooling medium, blowing carbon dioxide gas onto the surface of the mold shell after casting to accelerate the cooling and solidification speed of the casting and avoid shrinkage cavities and porosity in the casting.

Description

Technical Field

[0001] The present invention relates to the field of high - speed rail box body production, and particularly to a device and method for controlling the deformation and solidification of investment - cast high - speed rail box bodies. Background Art

[0002] The box body of the 600 - kilometer - per - hour super high - speed rail is a key component for installing electrical control equipment, and there are dozens of box bodies in each carriage. In the prior art, the manufacturing schemes for box bodies are as follows: 1. Using aluminum alloy plates with dimensions not less than 175 * 595 * 960 to complete part production through rough machining, heat treatment to eliminate machining stress, finish machining, surface treatment, and final inspection; the machining time on the machine tool is more than 300 hours, and the cost is high. 2. Sand - casting box bodies: mold making, molding, closing the mold, melting and pouring, sand cleaning and cutting, initial repair, initial inspection, heat treatment, correction, marking inspection, machining, surface treatment, and final part inspection; the internal quality of the castings is poor, the qualified rate is low, the deformation is large, the subsequent machining amount on the machine tool is large, and the machining is likely to cause deformation of the box body.

[0003] When producing box bodies by machining aluminum alloy plates on a machine tool, since the thickness of 80% of the area of this box body part is only 2mm, deformation is extremely likely to occur during the machining process. During finish machining, the feed rate of the machine tool is very small, and each part requires more than 300 hours of machining, resulting in very low production efficiency; at the same time, the material utilization rate is less than 4%, the material consumption is large, and the production cost is extremely high. When sand - casting aluminum alloy castings with dimensions exceeding 800mm, the minimum allowable wall thickness is not less than 6mm. Since the thickness of 80% of the area of this box body part is only 2mm, when using sand - casting production, the wall thickness of the casting needs to be increased to 6mm to ensure the formation of the casting, and then these casting process allowances are removed by machining later. The material utilization rate is only 25%, and the yield rate is low; the machining amount of the casting is large, the deformation is large after machining, and the processing efficiency is low. Generally, the maximum size of investment - cast aluminum alloy castings does not exceed 500mm, and for aluminum alloy castings with a size of 350mm, the wall thickness is not less than 3mm. Since the outer contour size of the high - speed rail box body is 175 * 595 * 960 and the wall thickness is only 2mm, such large - sized thin - wall wax parts are prone to serious deformation, difficult to pour and form, and it is not easy to ensure the internal quality of the casting, resulting in a low casting yield rate; therefore, general traditional investment casting does not produce such large - sized thin - wall castings. In view of this, this patent came into being. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and method for controlling the deformation and solidification of investment - cast high - speed rail box bodies.

[0005] The present invention is realized through the following technical solutions.

[0006] A method for controlling the deformation and solidification of investment - cast high - speed rail box bodies, the production method including the following steps: mold combination, shell making, wax removal, roasting, melting, casting, shell cleaning, and heat treatment;

[0007] Step A. Mould making combination: Make a wax part with a thickness of 2 mm and a necking structure with an inward flange. Use polystyrene soft tooling to finish and transfer the wax part. Prepare the coating, and the coating ratio is 35 - 40% silica sol, 60 - 65% mullite powder, and a small amount of defoamer and wetting agent.

[0008] Step B. Shell making: Make a mold shell. The number of shell-making layers is divided into a surface layer, a transition layer, and a reinforcement layer.

[0009] Step C. Wax removal: Use high-temperature steam for wax removal.

[0010] Step D. Roasting and melting: After completing Step C, complete the production of the mold shell through roasting.

[0011] Step E. Casting: Preheat the mold shell to a temperature of 650 - 700 °C, and carry out casting after maintaining the temperature for 0.5 - 1 hour.

[0012] Step F. Cooling: Blow carbon dioxide gas towards the mold shell that has completed casting using a pipe with an inner diameter of 8 mm.

[0013] Step G. Shell cleaning: Remove the mold shell.

[0014] Step H. Heat treatment: Carry out heat treatment work using a heat treatment tooling.

[0015] As a further technical solution, in Step B, the sand particle size of the surface layer is 120 mesh, the sand particle size of the transition layer is 30 - 60 mesh, and the sand particle size of the reinforcement layer is 16 - 30 mesh.

[0016] As a further technical solution, in Step C, when using high-temperature steam for wax removal, the wax removal steam pressure is between 0.6 and 0.8 MPa, the wax removal temperature is between 160 and 168 °C, and the steam pressure inlet time is less than 10 seconds.

[0017] As a further technical solution, in Step F, the blowing pressure of carbon dioxide is 6 - 10 MPa, and the blowing duration of carbon dioxide is 5 min. Cool the mold shell that has completed casting to complete the solidification of the casting.

[0018] As a further technical solution, in Step H, the heat treatment tooling is made of heat-resistant steel, and the tooling does not deform during the solution treatment of aluminum alloy, playing a role in restraining the box body, thereby reducing the deformation of the box body.

[0019] A device for controlling the deformation and solidification of an investment casting high-speed rail box body comprises a box body, a pouring system is installed on the box body, and a pouring pipe is on the left side of the pouring system, a carbon dioxide flow channel is arranged on the back of the box body, a left channel pipe is installed on the left side of the carbon dioxide flow channel, and a right channel pipe is installed on the right side of the carbon dioxide flow channel, a heat treatment tool is installed on the front side of the box body, and a horizontal tooling plate is arranged on the heat treatment tooling, and the horizontal tooling plate is fixedly connected to the vertical tooling plate.

[0020] Preferably, the pouring pipe is arranged on the outside of the box body, and the pouring pipe is wrapped around the outside of the carbon dioxide flow channel.

[0021] Preferably, the right channel tube, the left channel tube and the carbon dioxide flow channel are combined to form an "I" shape, and the right channel tube and the left channel tube are both connected to the carbon dioxide flow channel.

[0022] Preferably, the heat treatment tooling is in a rectangular shape as a whole, and is composed of three parts: an outer frame, a horizontal tooling plate and a vertical tooling plate. The horizontal tooling plate and the vertical tooling plate are combined together to form a "cross" shape.

[0023] The invention discloses an application of a device for controlling deformation and solidification of an investment cast high-speed rail box in a method for controlling deformation and solidification of an investment cast high-speed rail box.

[0024] A device for controlling the deformation and solidification of an investment-cast high-speed rail box is used to carry out investment casting of a high-speed rail box.

[0025] It can be seen from the above technical solutions that the beneficial effects of the present invention are:

[0026] The invention provides a device for controlling the deformation and solidification of an investment casting high-speed rail box body, which performs investment casting on the high-speed rail box body;

[0027] 1. Solve the problems of low production efficiency, low material utilization rate and high production cost when aluminum alloy sheets are processed by machine tools to produce boxes;

[0028] 2. Solve the problems of low sand casting yield, large machining volume of castings, large deformation after machining, and low machining efficiency;

[0029] 3. Generally, large thin-walled wax parts made by investment casting are prone to serious deformation, difficult to cast, difficult to ensure the internal quality of the casting, and low casting yield; for casting aluminum alloy boxes, the carbon dioxide cooling method can be used, which has a low temperature and a significant cooling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The structural diagram of a device for controlling the deformation and solidification of an investment casting high-speed rail box;

[0031] Figure 2Schematic diagram of the back of a device for controlling the deformation and solidification of a high-speed rail box in investment casting;

[0032] Figure 3 is Figure 1 side view of;

[0033] Figure 4 is Figure 1 rear view of;

[0034] Figure 5 is the internal structure of the box;

[0035] Figure 6 is the schematic diagram of the heat treatment tooling;

[0036] Figure 7 is Figure 1 3D view of;

[0037] Figure 8 is the top view of the heat treatment tooling;

[0038] Figure 9 is the comparison diagram of the pinhole state of the casting before and after use;

[0039] Figure 10 is the enlarged view of the pinhole state of the casting before use;

[0040] Figure 11 is the enlarged view of the pinhole state of the casting after use.

[0041] Reference numerals in the figure: 1. Box; 2. Gating system; 3. Carbon dioxide runner; 4. Right channel pipe; 5. Left channel pipe; 6. Pouring pipe; 7. Heat treatment tooling; 8. Horizontal tooling plate; 9. Vertical tooling plate. Detailed implementation method

[0042] The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention. The implementation conditions adopted in the embodiments can be further adjusted according to the conditions of the manufacturer, and the implementation conditions not described are usually conventional experimental conditions.

[0043] Embodiment

[0044] A method for controlling the deformation and solidification of a high-speed rail box in investment casting, and its production method includes the following steps: mold making combination, shell making, wax removal, roasting, melting, casting, shell cleaning, and heat treatment;

[0045] Step A. Mold making combination: Make a wax part with a wall thickness of 2 mm and a necking structure with an internal flanging, use polystyrene soft tooling to trim and transfer the wax part, prepare the coating, and the coating ratio is 35 - 40% silica sol, 60 - 65% mullite powder, and a small amount of defoaming agent and wetting agent;

[0046] Step B. Shell making: Make the mold shell. The number of shell-making layers is divided into the surface layer, the transition layer, and the reinforcement layer;

[0047] Step C. Wax removal: Use high-temperature steam for wax removal;

[0048] Step D. Roasting and melting: After completing Step C, further complete the production of the mold shell through roasting;

[0049] Step E. Casting: The preheating temperature of the mold shell is 650 - 700 °C. After maintaining the temperature for 0.5 - 1 hour, carry out casting;

[0050] Step F. Cooling: Use a pipeline with an inner diameter of 8 mm to blow carbon dioxide gas towards the mold shell that has completed casting;

[0051] Step G. Shell cleaning: Remove the mold shell;

[0052] Step H. Heat treatment: Carry out heat treatment work using a heat treatment tooling.

[0053] As a further technical solution, in Step B, the sand particle size of the surface layer is 120 mesh, the sand particle size of the transition layer is 30 - 60 mesh, and the sand particle size of the reinforcement layer is 16 - 30 mesh.

[0054] As a further technical solution, when using high-temperature steam for wax removal in Step C, the wax removal steam pressure is between 0.6 and 0.8 MPa, the wax removal temperature is between 160 and 168 °C, and the steam pressure inlet pressure time is less than 10 seconds.

[0055] As a further technical solution, in Step F, the blowing pressure of carbon dioxide is 6 - 10 MPa, and the blowing duration of carbon dioxide is 5 min. Cool the mold shell that has completed casting to complete the solidification work of the casting.

[0056] As a further technical solution, in Step H, the heat treatment tooling is made of heat-resistant steel, and it does not deform during the solution treatment of aluminum alloy, playing a role in restraining the box body, thereby reducing the deformation of the box body.

[0057] Such as Figure 1As shown in Figures 8 - 8: A device for controlling the deformation and solidification of a high - speed rail box body in investment casting, including a box body 1, on which a gating system 2 is installed. The left side of the gating system 2 is a pouring tube 6. At the same time, a carbon dioxide flow channel 3 is arranged on the back of the box body 1. A left channel tube 5 is installed on the left side of the carbon dioxide flow channel 3, and a right channel tube 4 is installed on the right side of the carbon dioxide flow channel 3. A heat treatment tooling 7 is installed on the front of the box body 1, and a horizontal tooling plate 8 is arranged on the heat treatment tooling 7, and the horizontal tooling plate 8 is fixedly connected to the vertical tooling plate 9; The heat treatment tooling 7 is integrally rectangular, and the heat treatment tooling 7 is composed of an outer frame, a horizontal tooling plate 8 and a vertical tooling plate 9. The horizontal tooling plate 8 and the vertical tooling plate 9 are combined to form a "cross" shape; The pouring tube 6 is arranged outside the box body 1, and the pouring tube 6 is wrapped outside the carbon dioxide flow channel 3; The right channel tube 4, the left channel tube 5 and the carbon dioxide flow channel 3 are combined to form a "worker" shape, and both the right channel tube 4 and the left channel tube 5 are communicated with the carbon dioxide flow channel 3.

[0058] As Figure 1-3 shown: Using carbon dioxide as a cooling medium, blowing carbon dioxide gas onto the surface of the mold shell after casting to accelerate the cooling and solidification speed of the casting, and avoid shrinkage cavities and porosity in the casting; The heat treatment tooling 7 is made of heat - resistant steel. The heat treatment tooling 7 is composed of a horizontal tooling plate 8 and a vertical tooling plate 9. During the solution treatment of aluminum alloy, the tooling does not deform and plays a role in restraining the box body 1, thereby reducing the deformation of the box body 1; Compared with the machining scheme, investment casting improves the production efficiency and material utilization rate of the box body 1 and reduces the processing cost of the box body 1; When trimming and transferring the wax pattern, a polystyrene soft tooling is used, which can reduce the deformation of the wax pattern, meet the dimensional requirements of the wax pattern, and further make the casting have less deformation.

[0059] The carbon dioxide cooling medium enters the interiors of the left channel tube 5 and the right channel tube 4 respectively through the carbon dioxide flow channel 3. The left channel tube 5 and the right channel tube 4 are strip - shaped and surround the inside of the box body 1. The carbon dioxide cooling medium has a low temperature, which accelerates the cooling of the casting, quickly reduces the temperature at the end, and reduces the defects of porosity and shrinkage cavities in the casting; Investment casting with shell - making and counter - gravity casting may result in lower production costs; The machining allowance of the parts is less, the production yield of the box body 1 is high, and compared with the machining scheme, investment casting improves the production efficiency and material utilization rate of the box body 1. The application of a device for controlling the deformation and solidification of a high - speed rail box body in investment casting in a method for controlling the deformation and solidification of a high - speed rail box body in investment casting.

[0060] Before use, it represents a product not prepared through carbon dioxide treatment. As Figure 9 shown is a comparison diagram of the pinhole states of the castings before use in the four groups on the left and the pinhole states of the castings after use on the right. Figure 10 is an enlarged view of the pinhole state of the casting before use. Figure 11 is an enlarged view of the pinhole state of the casting after use.

[0061] And Table 1 below is a comparison table of the performance of the main body of the box casting before and after use:

[0062] Table 1

[0063]

[0064] As can be seen from Table 1, in the method of the present invention, after using this device and this method, the tensile strength, the specified plastic extension strength, the elongation after fracture, and the Brinell hardness have all been significantly improved.

[0065] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, alterations, additions, or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for controlling the deformation and solidification of a high-speed rail box body in investment casting, characterized in that: The steps include: A. Mold making combination: Making a wax part with a necking structure with an inward flange, using polystyrene soft decoration to trim and transfer the wax part, preparing a coating, and the coating ratio is 35-40% silica sol, 60-65% mullite powder, defoaming agent and wetting agent; B. Shell making: The number of shell-making layers is divided into a surface layer, a transition layer and a reinforcement layer; C. Wax removal: Using high-temperature steam for wax removal; D. Roasting and melting: Completing the production of the mold shell through roasting; E. Casting: The preheating temperature of the mold shell is 650-700 °C, and casting is carried out after maintaining the temperature for 0.5-1 hour; F. Cooling: Using a pipeline to blow carbon dioxide gas towards the mold shell that has completed casting; G. Shell cleaning: Removing the mold shell; H. Heat treatment: Using a heat treatment tooling for heat treatment work; The device used: It includes a box body (1), a pouring system (2) is installed on the box body (1), and on the left side of the pouring system (2) is a pouring pipe (6). At the same time, a carbon dioxide flow channel (3) is arranged on the back of the box body (1), a left channel pipe (5) is installed on the left side of the carbon dioxide flow channel (3), and a right channel pipe (4) is installed on the right side of the carbon dioxide flow channel (3). A heat treatment tooling (7) is installed on the front of the box body (1), and a horizontal tooling plate (8) is arranged on the heat treatment tooling (7), and the horizontal tooling plate (8) is fixedly connected to the vertical tooling plate (9); The pouring pipe (6) is arranged outside the box body (1), and the pouring pipe (6) is wrapped outside the carbon dioxide flow channel (3); The right channel pipe (4), the left channel pipe (5) and the carbon dioxide flow channel (3) are combined together to form an "I" shape, and both the right channel pipe (4) and the left channel pipe (5) are communicated with the carbon dioxide flow channel (3); The heat treatment tooling (7) is integrally rectangular, and the heat treatment tooling (7) is composed of an outer frame, a horizontal tooling plate (8) and a vertical tooling plate (9). The horizontal tooling plate (8) and the vertical tooling plate (9) are combined together to form a "cross" shape.

2. A method for controlling the deformation and solidification of a high-speed rail box body by investment casting, characterized in that, In the described step A, the wall thickness of the wax part is 2 mm; the defoaming agent and the wetting agent are in a small amount; In the described step B, the sanding particle size of the surface layer is 120 mesh, the sanding particle size of the transition layer is 30-60 mesh, and the sanding particle size of the reinforcement layer is 16-30 mesh.

3. A method for controlling the deformation and solidification of a high-speed rail box body in investment casting, characterized in that, In the described step C, when using high-temperature steam for wax removal, the wax removal steam pressure is between 0.6 and 0.8 MPa, the wax removal temperature is between 160 and 168 °C, and the steam pressure inlet time is less than 10 seconds.

4. A method for controlling the deformation and solidification of a high-speed rail box body by investment casting, characterized in that, In the described step F, the blowing pressure of carbon dioxide is 6-10 MPa, the blowing duration of carbon dioxide is 5 min, the mold shell that has completed casting is cooled, and the solidification work of the casting is completed; the inner diameter of the pipeline is 8 mm.

5. A method for controlling the deformation and solidification of a high-speed rail box body by investment casting, characterized in that, In the described step H, the heat treatment tooling is made of heat-resistant steel, and the tooling does not deform during the solution treatment of aluminum alloy, playing a role in restraining the box body, thereby reducing the deformation of the box body.

6. A device for controlling the deformation and solidification of a high-speed rail box body in investment casting, comprising a box body (1), characterized in that, The box body (1) is installed with a pouring system (2), and the left side of the pouring system (2) is a pouring pipe (6), and the back of the box body (1) is provided with a carbon dioxide flow channel (3), the left side of the carbon dioxide flow channel (3) is provided with a left channel pipe (5), and the right side of the carbon dioxide flow channel (3) is provided with a right channel pipe (4), and the front of the box body (1) is installed with a heat treatment tool (7), and the heat treatment tool (7) is provided with a horizontal tool plate (8), and the horizontal tool plate (8) is fixedly connected to the vertical tool plate (9); The pouring pipe (6) is arranged on the outside of the box body (1), and the pouring pipe (6) is wrapped around the outside of the carbon dioxide flow channel (3); The right channel tube (4), the left channel tube (5) and the carbon dioxide flow channel (3) are combined together to form an "I" shape, and the right channel tube (4) and the left channel tube (5) are both connected to the carbon dioxide flow channel (3); The heat treatment tooling (7) is in a rectangular shape as a whole, and is composed of three parts: an outer frame, a horizontal tooling plate (8), and a vertical tooling plate (9). The horizontal tooling plate (8) and the vertical tooling plate (9) are combined together to form a "cross" shape.

7. Use of a device for controlling deformation and solidification of an investment cast high-speed rail box in a method for controlling deformation and solidification of an investment cast high-speed rail box, wherein the device is the device for controlling deformation and solidification of an investment cast high-speed rail box according to claim 6.

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