Cylindrical workpiece preparation system with flexible distribution of radial composition gradient

Abstract

The present invention relates to the field of material forming, specifically a system for preparing cylindrical workpieces with a flexible radial gradient distribution of composition. The designed rolling nozzle can realize the extrusion of the melt solidifying layer by layer, making the solidified structure denser. It is mainly used to prepare a cylindrical gradient material workpiece with a radial distribution of composition. It has the characteristics of high efficiency and flexible setting of the gradient composition distribution law. It is more suitable for the preparation of large-sized gradient material cylindrical workpieces; it has the characteristics of large size of formed workpieces and flexible gradient distribution. It can be prepared in large quantities with high efficiency, and can also be flexibly prepared in small batches and with multiple varieties. Compared with the additive manufacturing process achieved by directly spraying gradient composition droplets, the inner wall layer of the workpiece in contact with the rolling nozzle remains in a semi-solid paste zone, which can significantly reduce pore defects and slag inclusions.

Description

Technical Field

[0001] The invention relates to the technical field of material forming, in particular to a cylindrical workpiece preparation system with radial component gradient flexible distribution. Background Art

[0002] Gradient materials refer to materials whose chemical composition, microstructure, porosity and other factors change continuously or quasi-continuously from one side to the other along the thickness or length of the material, so that their physical, chemical and other properties change continuously in a gradient according to design requirements. These new composite materials with special functions have been widely used in aerospace, optical engineering, energy engineering, biomedical engineering, electromagnetic engineering, nuclear engineering and other fields.

[0003] Currently, the main technologies for preparing gradient materials include powder metallurgy, plasma spraying, self-propagating high-temperature synthesis (SHS), laser cladding, and centrifugal casting. However, these technologies still have many limitations when it comes to rapidly forming cylindrical workpieces with flexible radial composition gradients. For example, powder metallurgy and SHS are complex processes, plasma spraying and laser cladding are expensive, and centrifugal casting cannot quantitatively control the composition gradient distribution. Therefore, the challenge of efficiently and cost-effectively preparing cylindrical workpieces with radial composition gradients remains. Summary of the Invention

[0004] In response to the above problems, an embodiment of the present invention provides a cylindrical workpiece preparation system with a flexible distribution of radial component gradient.

[0005] An embodiment of the present invention provides a cylindrical workpiece preparation system with a flexible distribution of radial composition gradient, comprising a mold body, a rolling nozzle, a temperature control device, a rotary drive device, a mixer, N melting furnaces, and a flow control device; wherein,

[0006] N melting furnaces store raw materials of different compositions respectively, and are connected to the mixer via pipelines respectively, for melting the stored raw materials into melt and sending the melt to the mixer;

[0007] The mixer is used to heat the melt flowing into it while stirring and mixing to obtain a mixed melt, and heat the mixed melt to a set temperature;

[0008] The temperature control device is used to preheat and cool the mold body, and the rotation drive device is used to drive the mold body to roll at a certain speed;

[0009] The mold body has an inner cavity for solidifying the mixed melt flowing into the inner cavity from the rolling nozzle layer by layer to prepare the molding;

[0010] The rolling nozzle is connected to the mixer through a pressurized pipe and is used to extend into the inner cavity of the mold body and squeeze with the inner wall of the mold body during the preparation process, so that the mixed melt flowing out is poured layer by layer on the inner surface of the mold body under the action of extrusion during the rolling process of the mold body;

[0011] The flow control device is used to monitor and control the flow of the melt or mixed melt in the pipes flowing into and out of the mixer.

[0012] Optional, preparation phase:

[0013] According to the composition requirements of the outer surface of the cylindrical workpiece, corresponding alloy raw materials are placed in N melting furnaces. The N melting furnaces melt the alloy raw materials into a melt. The flow rate of each pipeline connecting the N melting furnaces and the mixer is controlled by valves in each pipeline so that the mixer is filled with a melt with the same composition as the outer surface of the cylindrical workpiece. The mixer heats the melt to a preset temperature and stirs and mixes it to obtain a mixed melt. The temperature control device is activated to heat the mold body to the preheating temperature.

[0014] Preparation stage:

[0015] The flow control device adjusts the valve on the boost pipe so that the flow rate of the mixed melt flowing out of the mixer meets the set requirements. Then, the valves on each pipe are adjusted to calculate the flow rate of the melt in each pipe according to the gradient composition and the workpiece size, so that the amount of melt flowing into the mixer is the same as the amount of mixed melt flowing out of the mixer.

[0016] The rolling nozzle extends into the inner cavity of the mold body and squeezes against the inner wall of the mold body; the rotary drive device is started to drive the mold body to roll, and the mixed melt sprayed from the rolling nozzle contacts the inner wall of the mold body and begins to solidify when it cools. The solidified melt layer on the inner wall of the mold body contacts the poured superheated melt and melts and mixes until it becomes a semi-solid paste. At this time, the flow rate of the mixed melt flowing out of the rolling nozzle is reduced; as the mold body rotates and the outer wall cools, the mixed melt in the mold body is stably solidified layer by layer; the flow control device adjusts the opening of each valve so that the composition of the mixed melt flowing out of the rolling nozzle changes continuously, so that the radial composition gradient change law of the cylindrical workpiece meets the set requirements.

[0017] Optionally, the mold body is composed of two semi-cylinders, which are molded together to form a cylinder with a cylindrical inner cavity, and one side of the cylinder has a circular hole for the rolling nozzle to enter.

[0018] Optionally, the rolling nozzle includes a nozzle body, the cross-section of the nozzle body is an inverted trapezoid with an arc-shaped upper side, a cylindrical first inner cavity and a second inner cavity are arranged in parallel in the upper and lower parts of the nozzle body, a connecting channel is provided between the first inner cavity and the second inner cavity, a liquid inlet pipe connected to the first inner cavity is provided on the side of the nozzle body, a liquid outlet gap of equal length to the second inner cavity is provided on the bottom surface of the nozzle body, a liquid outlet mechanism is provided at the liquid outlet gap, and when the rolling nozzle is squeezed against the inner wall of the mold body, a gap appears between the liquid outlet mechanism and the liquid outlet gap, so that the mixed melt flows out from the gap.

[0019] Optionally, the liquid discharge mechanism includes a fixed elastic connecting rod and a rolling cylinder, one end of the fixed elastic connecting rod is fixed to the inner wall of the first inner cavity, and the other end is fixed to the rolling cylinder. In the natural state, the rolling cylinder is sealed in the liquid discharge gap under the action of the fixed elastic connecting rod. In the working state, the rolling cylinder and the mold body are squeezed to form a gap between the rolling cylinder and the liquid discharge gap, so that the mixed melt flows out from the gap.

[0020] Optionally, the process of calculating the flow rate of the melt in each pipe based on the gradient composition and the workpiece size includes:

[0021] When the gradient law ω of the cylindrical workpiece component i is obtained i (s), the calculation process is as follows:

[0022] 1) Before pouring begins, the concentration of ω flows from N melting furnaces into the mixer i The melt volume of (0) is V0, and the melt volume flowing out of each melting furnace meets the conditions:

[0023] (1)

[0024] 2) During the pouring process, monitor the concentration of ω ij The melt flows out of the jth pipe at time t with a velocity v j , based on the fact that the flow rates flowing into and out of the mixer are the same, calculate the mixer outflow flow rate V out for:

[0025] (2)

[0026] 3) Further calculate the wall thickness s of the formed cylindrical workpiece at time t:

[0027] (3)

[0028] Wherein, R is the inner cavity radius of the mold body, and L is the inner cavity length of the mold body;

[0029] 4) Since the amount of component i flowing out of the mixer and in the mixer is equal to the amount of component i flowing into the mixer, we have:

[0030] (4)

[0031] Combining the above formulas, we can calculate the flow rate v of the melt in each pipe at each moment t. j .

[0032] Compared with the existing technology, the beneficial effect of the present invention is that the designed rolling nozzle can realize the extrusion effect on the melt solidifying layer by layer, making the solidified structure denser. It is mainly used to prepare a cylindrical gradient material workpiece with radial component distribution. It has the characteristics of high efficiency and flexible setting of gradient component distribution law. It is more suitable for the preparation of large-sized gradient material cylindrical workpieces; it has the characteristics of large formed workpiece size and flexible gradient distribution. It can be prepared in large quantities with high efficiency, and can also be flexibly prepared in small batches and with multiple varieties. Compared with the additive manufacturing process achieved by directly spraying gradient component droplets, the inner wall layer of the workpiece in contact with the rolling nozzle remains in a semi-solid paste zone, which can significantly reduce porosity defects and slag inclusions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. In the drawings:

[0034] Figure 1 A schematic diagram of the system layout is provided for an embodiment of the present invention;

[0035] Figure 2 It is a three-dimensional schematic diagram of the main part of the mold of the present invention;

[0036] Figure 3 This is a cross-sectional view of the main body of the mold of the present invention;

[0037] Figure 4 This is a schematic diagram of the three-dimensional structure of the rolling nozzle of the present invention;

[0038] Figure 5 This is a cross-sectional view of the rolling nozzle of the present invention when no mixed melt flows out;

[0039] Figure 6 This is a cross-sectional view of the rolling nozzle of the present invention when the mixed melt flows out.

[0040] Figure 7 This is a schematic diagram of the logic control principle of the flow control device of the present invention.

[0041] Among them, there are a semi-cylinder 1, a cylindrical inner cavity 2, a circular hole 3, a nozzle body 4, a first inner cavity 5, a second inner cavity 6, a connecting channel 7, a liquid inlet pipe 8, a fixed elastic connecting rod 9, and a rolling cylinder 10. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0043] See also Figure 1 , an embodiment of the present invention provides a cylindrical workpiece preparation system with a flexible distribution of radial component gradient.

[0044] An embodiment of the present invention provides a cylindrical workpiece preparation system with a flexible distribution of radial composition gradient, comprising a mold body, a rolling nozzle, a temperature control device, a rotary drive device, a mixer, N melting furnaces, and a flow control device; wherein,

[0045] N melting furnaces store raw materials of different compositions respectively, and are connected to the mixer via pipelines respectively, for melting the stored raw materials into melt and sending the melt to the mixer;

[0046] The mixer is used to heat the melt flowing into it while stirring and mixing to obtain a mixed melt, and heat the mixed melt to a set temperature;

[0047] The temperature control device is used to preheat and cool the mold body, and the rotation drive device is used to drive the mold body to roll at a certain speed;

[0048] The mold body has an inner cavity for solidifying the mixed melt flowing into the inner cavity from the rolling nozzle layer by layer to prepare the molding;

[0049] The rolling nozzle is connected to the mixer through a pressurized pipe and is used to extend into the inner cavity of the mold body and squeeze with the inner wall of the mold body during the preparation process, so that the mixed melt flowing out is poured layer by layer on the inner surface of the mold body under the action of extrusion during the rolling process of the mold body;

[0050] The flow control device is used to monitor and control the flow of the melt or mixed melt in the pipes flowing into and out of the mixer.

[0051] In practice, the temperature control device, the rotary drive device, the mixer and the flow control device are not the invention points of this application. Existing equipment that can realize the corresponding functions can be selected and will not be described in detail here.

[0052] In the specific implementation, preparation stage:

[0053] According to the composition requirements of the outer surface of the cylindrical workpiece, corresponding alloy raw materials are placed in N melting furnaces. The N melting furnaces melt the alloy raw materials into a melt. The flow rate of each pipeline connecting the N melting furnaces and the mixer is controlled by valves in each pipeline so that the mixer is filled with a melt with the same composition as the outer surface of the cylindrical workpiece. The mixer heats the melt to a preset temperature and stirs and mixes it to obtain a mixed melt. The temperature control device is activated to heat the mold body to the preheating temperature.

[0054] Preparation stage:

[0055] The flow control device adjusts the valve on the boost pipe so that the flow rate of the mixed melt flowing out of the mixer meets the set requirements. Then, the valves on each pipe are adjusted to calculate the flow rate of the melt in each pipe according to the gradient composition and the workpiece size, so that the amount of melt flowing into the mixer is the same as the amount of mixed melt flowing out of the mixer.

[0056] The rolling nozzle extends into the inner cavity of the mold body and squeezes against the inner wall of the mold body; the rotary drive device is started to drive the mold body to roll, and the mixed melt sprayed from the rolling nozzle contacts the inner wall of the mold body and begins to solidify when it cools. The solidified melt layer on the inner wall of the mold body contacts the poured superheated melt and melts and mixes until it becomes a semi-solid paste. At this time, the flow rate of the mixed melt flowing out of the rolling nozzle is reduced; as the mold body rotates and the outer wall cools, the mixed melt in the mold body is stably solidified layer by layer; the flow control device adjusts the opening of each valve so that the composition of the mixed melt flowing out of the rolling nozzle changes continuously, so that the radial composition gradient change law of the cylindrical workpiece meets the set requirements.

[0057] In implementation, see Figure 2 and Figure 3 The mold body consists of two semi-cylinders 1. After the two semi-cylinders are molded together, a cylinder with a cylindrical inner cavity 2 is formed. A circular hole 3 is provided on one side of the cylinder to allow the rolling nozzle to enter.

[0058] See also Figure 4 、 Figure 5 and Figure 6 The rolling nozzle includes a nozzle body 4. The cross-section of the nozzle body 4 is an inverted trapezoid with an arc-shaped upper side. A cylindrical first inner cavity 5 and a second inner cavity 6 are arranged in parallel in the upper and lower parts of the nozzle body 4. A connecting channel 7 is provided between the first inner cavity 5 and the second inner cavity 6. A liquid inlet pipe 8 connected to the first inner cavity 5 is provided on the side of the nozzle body 4. A liquid outlet gap of equal length is provided on the bottom surface of the nozzle body 4. A liquid outlet mechanism is provided at the liquid outlet gap. When the rolling nozzle is squeezed against the inner wall of the mold body, a gap appears between the liquid outlet mechanism and the liquid outlet gap, so that the mixed melt flows out from the gap.

[0059] Specifically, the liquid discharge mechanism includes a fixed elastic connecting rod 9 and a rolling cylinder 10. One end of the fixed elastic connecting rod 9 is fixed to the inner wall of the first inner cavity 5, and the other end is fixed to the rolling cylinder 10. In the natural state, the rolling cylinder 10 is sealed in the liquid discharge gap under the action of the fixed elastic connecting rod 9. In the working state, the rolling cylinder 10 is squeezed with the mold body to form a gap between the rolling cylinder 10 and the liquid discharge gap, so that the mixed melt flows out from the gap.

[0060] During implementation, the flow control device can automatically adjust the alloy melt outflow rate of each melting furnace according to the target composition gradient along the radial direction. Specifically, the process of calculating the flow rate of the melt in each pipe according to the gradient composition and the workpiece size includes:

[0061] When the gradient law ω of the cylindrical workpiece component i is obtained i (s), the calculation process is as follows:

[0062] 1) Before pouring begins, the concentration of ω flows from N melting furnaces into the mixer i The melt volume of (0) is V0, and the melt volume flowing out of each melting furnace meets the conditions:

[0063] (1)

[0064] 2) During the pouring process, monitor the concentration of ω ij The melt flows out of the jth pipe at time t with a velocity v j , based on the fact that the flow rates flowing into and out of the mixer are the same, calculate the mixer outflow flow rate V out for:

[0065] (2)

[0066] 3) Further calculate the wall thickness s of the formed cylindrical workpiece at time t:

[0067] (3)

[0068] Wherein, R is the inner cavity radius of the mold body, and L is the inner cavity length of the mold body;

[0069] 4) Since the amount of component i flowing out of the mixer and in the mixer is equal to the amount of component i flowing into the mixer, we have:

[0070] (4)

[0071] Combining the above formulas, we can calculate the flow rate v of the melt in each pipe at each moment t. j .

[0072] Examples

[0073] The goal is to prepare a 2m long, 0.3m outer radius, and 0.1m thick component i with a gradient law along the radial thickness direction of ω i (s)=2s 2 +s+0.05 cylindrical workpiece. It is known that the concentrations of i in three melting furnaces are 0.2, 0.1, and 0.02 respectively, and the melt volume V0 in the mixer is 0.2m 3 . From formula (2), we can calculate:

[0074]

[0075] The mixer outflow rate V out The relationship between the concentration of component i is:

[0076]

[0077] According to the conservation of melt volume and composition i, the flow rate of each pipeline satisfies the following relationship:

[0078]

[0079]

[0080] Among them, the flow rate V out It is obtained through equipment monitoring.

[0081] The solution provided by the embodiment of the present invention can realize the extrusion effect on the melt solidifying layer by layer through the designed rolling nozzle, making the solidified structure denser. It is mainly used to prepare a cylindrical gradient material workpiece with radial component distribution. It has the characteristics of high efficiency and flexible setting of gradient component distribution law. It is more suitable for the preparation of large-sized gradient material cylindrical workpieces; it has the characteristics of large-sized formed workpieces and flexible gradient distribution. It can be prepared in large quantities with high efficiency, and can also be flexibly prepared in small batches and with multiple varieties. Compared with the additive manufacturing process achieved by directly spraying gradient component droplets, the inner wall layer of the workpiece in contact with the rolling nozzle remains in a semi-solid paste zone, which can significantly reduce porosity defects and slag inclusions.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A cylindrical workpiece preparation system with flexible radial gradient distribution, characterized in that: It includes a mold body, a rolling nozzle, a temperature control device, a rotary drive device, a mixer, N melting furnaces and a flow control device; wherein, N melting furnaces store raw materials of different compositions respectively, and are connected to the mixer via pipelines respectively, for melting the stored raw materials into melt and sending the melt to the mixer; The mixer is used to heat the melt flowing into it while stirring and mixing to obtain a mixed melt, and heat the mixed melt to a set temperature; The temperature control device is used to preheat and cool the mold body, and the rotation drive device is used to drive the mold body to roll at a certain speed; The mold body has an inner cavity for solidifying the mixed melt flowing into the inner cavity from the rolling nozzle layer by layer to prepare the molding; The rolling nozzle is connected to the mixer through a pressurized pipe and is used to extend into the inner cavity of the mold body and squeeze with the inner wall of the mold body during the preparation process, so that the mixed melt flowing out is poured layer by layer on the inner surface of the mold body under the action of extrusion during the rolling process of the mold body; The flow control device is used to monitor and control the flow of the melt or mixed melt in the pipes flowing into and out of the mixer; The mold body consists of two semi-cylinders, which are combined to form a cylindrical body with a cylindrical inner cavity. One side of the cylinder has a circular hole for the roller nozzle to enter. The rolling nozzle includes a nozzle body, the cross-section of the nozzle body is an inverted trapezoid with an arc-shaped upper side, a cylindrical first inner cavity and a second inner cavity are arranged in parallel in the upper and lower parts of the nozzle body, a connecting channel is provided between the first inner cavity and the second inner cavity, a liquid inlet pipe connected to the first inner cavity is provided on the side of the nozzle body, and a liquid outlet gap connected to the second inner cavity and of equal length is provided on the bottom surface of the nozzle body, and a liquid outlet mechanism is provided at the liquid outlet gap. When the rolling nozzle is squeezed against the inner wall of the mold body, a gap is formed between the liquid outlet mechanism and the liquid outlet gap, so that the mixed melt flows out from the gap. The process of calculating the flow rate of the melt in each pipe based on the gradient composition and the workpiece size includes: When the gradient law ω of the cylindrical workpiece component i is obtained i (s), the calculation process is as follows: 1) Before pouring begins, the concentration of ω flows from N melting furnaces into the mixer i The melt volume of (0) is V0, and the melt volume flowing out of each melting furnace meets the conditions: （1） 2) During the pouring process, monitor the concentration of ω ij The melt flows out of the jth pipe at time t with a flow rate of v j , based on the fact that the flow rates flowing into and out of the mixer are the same, calculate the mixer outflow flow rate V out for: （2） 3) Further calculate the wall thickness s of the formed cylindrical workpiece at time t: （3） Wherein, R is the inner cavity radius of the mold body, and L is the inner cavity length of the mold body; 4) Since the amount of component i flowing out of the mixer and in the mixer is equal to the amount of component i flowing into the mixer, we have: （4） Combining the above formulas, we can calculate the flow rate v of the melt in each pipe at each moment t. j .

2. The cylindrical workpiece preparation system with radial component gradient flexible distribution according to claim 1, characterized in that: Preparation stage: According to the composition requirements of the outer surface of the cylindrical workpiece, corresponding alloy raw materials are placed in N melting furnaces. The N melting furnaces melt the alloy raw materials into a melt. The flow rate of each pipeline connecting the N melting furnaces and the mixer is controlled by valves in each pipeline so that the mixer is filled with a melt with the same composition as the outer surface of the cylindrical workpiece. The mixer heats the melt to a preset temperature and stirs and mixes it to obtain a mixed melt. The temperature control device is activated to heat the mold body to the preheating temperature. Preparation stage: The flow control device adjusts the valve on the boost pipe so that the flow rate of the mixed melt flowing out of the mixer meets the set requirements. Then, the valves on each pipe are adjusted to calculate the flow rate of the melt in each pipe according to the gradient composition and the workpiece size, so that the amount of melt flowing into the mixer is the same as the amount of mixed melt flowing out of the mixer. The rolling nozzle extends into the inner cavity of the mold body and squeezes against the inner wall of the mold body; The rotary drive device is started to drive the mold body to roll. The mixed melt sprayed from the rolling nozzle contacts the inner wall of the mold body and begins to solidify when it cools. The solidified melt layer on the inner wall of the mold body contacts the superheated melt poured and melts and mixes until it becomes a semi-solid paste. At this time, the flow rate of the mixed melt flowing out of the rolling nozzle is reduced; as the mold body rotates and the outer wall cools, the mixed melt in the mold body is stably solidified layer by layer; the flow control device adjusts the opening of each valve so that the composition of the mixed melt flowing out of the rolling nozzle changes continuously, so that the radial composition gradient change law of the cylindrical workpiece meets the set requirements.

3. The cylindrical workpiece preparation system with radial gradient flexible distribution according to claim 1, characterized in that: The liquid discharge mechanism includes a fixed elastic connecting rod and a rolling cylinder. One end of the fixed elastic connecting rod is fixed to the inner wall of the first inner cavity, and the other end is fixed to the rolling cylinder. In the natural state, the rolling cylinder is sealed in the liquid discharge gap under the action of the fixed elastic connecting rod. In the working state, the rolling cylinder and the mold body are squeezed to form a gap between the rolling cylinder and the liquid discharge gap, so that the mixed melt flows out from the gap.

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