An electromagnetic launch rail surface reconstruction method

Abstract

The present invention relates to a method for reconstructing the surface of an electromagnetic launch track, belonging to the technical field of electromagnetic track launch. The present invention uses the electromagnetic launch armature material and the track material as a friction pair, adopts a pin-on-disk friction device, and introduces an electric current to the friction pair in the pin-on-disk friction device; by changing at least one parameter among the magnitude of the electric current, the contact pressure of the friction pair, the friction speed, the friction time, and the arcing distance, the surface microstructure of the track material under the corresponding conditions is obtained; based on the surface microstructure obtained from the experiment, the surface structure of the electromagnetic launch track is reconstructed. The present invention realizes for the first time the accumulation of original data of topography reconstruction such as friction and wear on the surface of the track material, material transfer on the surface, and arc ablation on the surface, providing necessary conditions for the subsequent systematic reconstruction of the surface of the electromagnetic launch track. The method of the present invention is reasonable, the process is simple and controllable, the obtained data is true and reliable, and it is convenient for large-scale application.

Description

Technical Field

[0001] The present invention relates to a method for reconstructing the surface of an electromagnetic launch rail, belonging to the technical field of electromagnetic rail launch. Background Art

[0002] The electromagnetic rail launch technology is a new launch method that uses electromagnetic energy to push an object to achieve ultra-high-speed launch, which consists of two parallel metal rails and a current-carrying armature sandwiched between them. During the launch process, after a pulsed current flows into one of the rails, it flows out through the armature in the middle and then through the other rail. A strong magnetic field is formed between the parallel metal rails. The current-carrying armature in the middle generates a Lorentz force under the action of the strong magnetic field, thereby pushing the armature carrying the warhead out at high speed. In order to ensure good electrical contact performance between the armature and the rail and form a complete closed loop, an interference fit assembly method is generally used between the armature and the rail.

[0003] The copper alloy rail is a key part of the electromagnetic rail launch device. Its surface topography and physical properties have a decisive impact on the launch behavior and launch accuracy. During the actual launch process, due to the high-speed current-carrying friction and wear between the rail and the armature, the tissue topography and physical properties of the rail surface will change with the increase in the number of launches, and the tissue topography and physical properties of different regions on the rail surface are also very different. The existing research methods for the rail surface mainly involve disassembling and sampling the rail after actual launch. Limited by the structure and assembly method of the electromagnetic rail launch device, the disassembly cost is high, and it cannot be restored after disassembly. Therefore, it is not advisable to directly take a large number of samples from the electromagnetic rail launcher to study the rail surface. Therefore, a laboratory electromagnetic launch rail surface reconstruction technology is needed to obtain sufficient samples for studying the tissue structure and physical properties of the rail surface.

[0004] In view of the above problems, most of the existing solutions obtain the surface microstructure and performance parameters of the rail by means of in-bore detection and disassembly sampling detection. Chinese Patent Publication No. CN 108760768B discloses an in-bore automatic scanning detection trolley for an electromagnetic rail launch device. The device drives the trolley to move in the in-bore of the electromagnetic rail launch device through a motor. A line laser with a thin and bright line is emitted by a laser scanning mechanism and reflected by the emission surface so that the line laser is perpendicularly irradiated on the rail surface. The line laser on the guide rail surface is obtained through a high-definition camera mechanism to obtain the rail morphology point cloud, so as to realize the acquisition of the rail surface morphology. This method can only analyze and detect the rail surface morphology and cannot obtain the surface microstructure and physical property information; Chinese Patent Publication No. CN 111076607B discloses a rail-type electromagnetic material performance test platform, which can simulate the real launch of a rail electromagnetic gun in the laboratory and test the armature performance and rail performance after the launch of the rail electromagnetic gun. The device of this invention can facilitate the disassembly of the rail. When testing the performance of the disassembled rail, it is necessary to take samples by damaging the rail, so the detection cost is relatively high. To sum up, limited by the limited size in the bore, the in-bore detection method cannot detect its organizational structure and physical properties; while the complex assembly method and destructive physical property research result in too high research losses to accept the process research cost. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention first proposes to obtain data samples through a pin-on-disc friction experiment under laboratory conditions and reconstruct the surface microstructure of the electromagnetic launch rail based on the data samples.

[0006] The present invention aims to provide a method with reasonable process and easy-to-control technological process, which can reconstruct the microstructural organization of the rail in different launch times and different position areas by changing the current-carrying friction process parameters, and provide sufficient samples for the evolutionary research of the surface organizational structure and physical properties of the electromagnetic launch rail.

[0007] The present invention uses the electromagnetic launch armature material and the rail material as the friction pair, adopts a pin-on-disc friction device, and introduces current to the friction pair in the pin-on-disc friction device; by changing at least one parameter among the current magnitude, the contact pressure of the friction pair, the friction speed, the friction time, and the arcing distance, the surface organizational structure of the rail material under the corresponding conditions is obtained; the surface structure of the electromagnetic launch rail is reconstructed based on the surface organizational structure obtained from the experiment.

[0008] The surface organizational structure obtained by the rail material under the corresponding experimental conditions is selected from at least one of a surface friction and wear structure, a material transfer structure, and an arc ablation structure.

[0009] The present invention adopts a high-speed current-carrying friction and wear method on a pin-on-disc friction device, and by changing at least one parameter among the current magnitude, the contact pressure of the friction pair, the friction speed, the friction time, and the arcing distance, an orbital surface morphology structure and physical properties similar to those after actual launch are formed, thereby achieving the purpose of the present invention. The current used therein is less than or equal to 1000 A (far lower than 300 kA in the prior art, and the data source is "The Development and Current Situation of Electromagnetic Railgun Launch Technology" published by Li Jun et al. in the journal "High Voltage Engineering"), and preferably 200 - 600 A; in combination with the present invention, the current density is preferably 2 - 8 A / mm 2 .

[0010] The contact pressure of the friction pair is 1 - 5 MPa, and the friction speed is 4000 - 7000 rpm; preferably 4000 - 6000 rpm.

[0011] During arcing, the spacing between the friction pair is 1 - 10 mm, preferably 2 - 8 mm, which is conducive to obtaining morphologies such as arc ablation.

[0012] The pin-on-disc friction device used in the present invention can greatly reduce the space and site required for experiments. Moreover, by adopting corresponding experimental parameters (differences in orders of magnitude) that are much smaller than the current, pressure, friction speed, etc. used in the existing electromagnetic rail launch technology (especially electromagnetic guns), as many samples as possible are obtained in the parameter environment achievable in the laboratory, thereby providing necessary conditions for constructing the evolution of the surface tissue structure of the electromagnetic launch track.

[0013] The present invention uses the pin-on-disc friction and wear method. Although the current density, pressure, and friction speed during the reconstruction process are lower than those in the actual launch condition, due to the use of a rotary friction method, the wear degree, material transfer amount, and ablation degree of the disc specimen can produce a superimposed effect, and controlling the relevant parameters can achieve the reconstruction of a morphology similar to that of the actual launch track surface.

[0014] The current-carrying function of the pin-on-disc friction device in the present invention is realized by externally installing a power supply system. After the current is generated by the power supply system, it flows from one pin into the disc specimen and then flows out from another pin specimen ( Figure 6 ), where the diameter of the disc specimen is 180 mm, and the pin specimen is a cylinder with a diameter of 10 mm. In the present invention, the material of the disc specimen is the same as that used for the rail, and the pin specimen is the same as that used for the armature. The pin specimen is connected to the power supply, and there is an insulating layer between the pin specimen and the pressurizing device. Such a design is conducive to further enhancing the superimposed effect.

[0015] In the research and development process of the present invention, it is found that: in the friction process, it is relatively difficult to reconstruct the structure of material transfer and the structure of arc ablation. Through research, it is found that for the problem of insignificant material transfer, the present invention first attempts to heat the friction environment with a resistance wire to soften the armature material and accelerate material transfer. For the reconstruction of the arc ablation structure, it is mainly necessary to control the arc starting distance. Therefore, the present invention uses a motor slide rail to accurately control the position of the friction pair, so that the distance between the friction pairs can be accurately adjusted, thereby realizing the actual control of the arc starting.

[0016] A method for reconstructing the surface of an electromagnetic launch track according to the present invention. This technology is carried out on a pin-on-disc friction and wear testing machine, with the electromagnetic launch armature material and the track material as the friction pair. A certain amount of current is passed between the friction pairs to realize the current-carrying friction process of the friction pair, and at least one of the morphologies such as friction and wear, material transfer, and arc ablation is formed on the surface of the friction pair.

[0017] The present invention has realized for the first time the accumulation of original data on the reconstruction of the morphologies such as friction and wear, surface material transfer, and surface arc ablation on the surface of the electromagnetic track material under pressure and conductive conditions, providing the necessary conditions for the subsequent system reconstruction.

[0018] A method for reconstructing the surface of an electromagnetic launch track according to the present invention. When the track material is CuCrZr alloy and the armature material is 7075Al alloy,

[0019] Control the current density of the current-carrying friction process to be 2-8 A / mm 2 、preferably 4-8 A / mm 2 ;

[0020] Control the contact pressure of the friction pair to be 1-5 MPa, preferably 1.5-3 MPa;

[0021] Control the friction speed to be 4000-6000 rpm.

[0022] For the above-mentioned controlled parameters, if the parameters are controlled below the above range, the reconstruction effect is not obvious and it is impossible to realize the reconstruction of a morphology similar to the surface of the actual launch track; if the parameters are controlled above the above range, first, the requirements for the experimental equipment are higher and the required cost is too large, and second, the reconstruction time is not easy to control and the reconstructed morphology is prone to excessive accumulation.

[0023] A technology for reconstructing the surface of an electromagnetic launch track according to the present invention. When the track material is CuCrZr alloy and the armature material is 7075Al alloy, control the ambient temperature to be 300-500 °C; this temperature can be used to compensate the temperature of the current-carrying friction process; the ambient temperature is heated and controlled by a resistance wire.

[0024] It was found during the research that when the environmental temperature is greater than 400 - 500 °C, the armature material can be softened during the friction process, resulting in obvious material transfer.

[0025] For a surface reconstruction technology of an electromagnetic emission track according to the present invention, when the track material is a CuCrZr alloy, the armature material is a 7075Al alloy, and the current density during the current-carrying friction process is 2 - 8 A / mm 2 、when controlling the contact pressure of the friction pair to be 1.5 - 3 MPa and the friction speed to be 4000 - 6000 rpm, after friction for at least 4 minutes, arcing occurs, and the distance between the friction pair during arcing is 3 - 8 mm, obtaining an arc ablation morphology.

[0026] When applied industrially, power is continuously supplied and the rotation speed is continuously maintained after arcing. Experiments have found that under the conditions defined in the present invention, an obvious arc ablation morphology can be obtained 2 minutes after arcing.

[0027] For a surface reconstruction technology of an electromagnetic emission track according to the present invention, when the track material is a CuCrZr alloy, the armature material is a 7075Al alloy, and the current density during the current-carrying friction process is 2 - 8 A / mm 2 、when controlling the contact pressure of the friction pair to be 1.5 - 3 MPa and the friction speed to be 4000 - 6000 rpm, after friction for at least 4 minutes, a friction and wear morphology is obtained as the main one.

[0028] For a surface reconstruction technology of an electromagnetic emission track according to the present invention, when the track material is a CuCrZr alloy, the armature material is a 7075Al alloy, and the current density during the current-carrying friction process is 2 - 8 A / mm 2 、when controlling the contact pressure of the friction pair to be 1.5 - 3 MPa, the friction speed to be 4000 - 6000 rpm, and the environmental temperature to be 450 - 500 °C, after friction for at least 5 minutes, a material transfer morphology is obtained as the main one.

[0029] Based on the morphologies obtained from the above experiments, the present invention can reconstruct the surface structure of the electromagnetic emission track.

[0030] The reconstruction method of the present invention is reasonable, the process is easy to control, and it can simply and efficiently obtain reconstructed samples of the track microstructural organization with different numbers of launches and different position regions.

[0031] The method of the present invention for reconstructing the microstructure of the track in different firing times and different position regions by using the laboratory current-carrying wear experiment can reconstruct the surface friction and wear, material transfer, arc ablation and other morphologies of the track after electromagnetic launch by controlling the current-carrying friction and wear process, temperature compensation and the arc starting moment by controlling the distance between the friction pairs. Since the morphological characteristics of different regions of the track are different during the actual launch process and the degree of morphological characteristics also varies with the accumulation of the firing times, and the current-carrying friction and wear experiment is used in the present invention, and by controlling the process parameters, three different morphologies can be reconstructed, and morphologies with different degrees of characteristics can also be obtained by adjusting the parameters. Therefore, the reconstruction of the microstructure of the track in different firing times and different position regions can be realized.

[0032] For the material analysis samples after the track is in service, the current basic method is to disassemble and analyze the track after launch. In the present invention, a method is formed to obtain samples similar to the track after actual launch under laboratory conditions, avoiding the destructive disassembly of the electromagnetic launcher. Its cost and cycle are greatly improved compared with the disassembly method, and the reconstruction process is simple, and the process method is easy to operate and control. Description of the Drawings

[0033] Attached Figure 1 is the actual morphology diagram of the track (made of CuCrZr alloy) that has reached the service life;

[0034] Attached Figure 2 is the reconstructed surface morphology diagram obtained in Example 1;

[0035] Attached Figure 3 is the reconstructed surface morphology diagram obtained in Example 2;

[0036] Attached Figure 4 is the reconstructed surface morphology diagram obtained in Example 3;

[0037] Attached Figure 5 is the reconstructed surface morphology diagram obtained in Comparative Example 2;

[0038] Attached Figure 6 is the schematic diagram of the current-carrying friction and wear equipment. Detailed Embodiments

[0039] In the embodiments and comparative examples, the structure of the current-carrying friction and wear equipment is as Figure 6 shown, wherein the material of the disc specimen is the same as that of the guide rail (specifically CuCrZr alloy material); the pin specimen is the same as the material of the armature (specifically 7075Al alloy material); the diameter of the disc specimen is 180 mm, and the pin specimen is a cylinder with a diameter of 10 mm.

[0040] Example 1

[0041] First, adjust the contact pressure of the friction pair to 2.5 MPa. After the pressure stabilizes, increase the rotational speed to 5000 rpm and heat the ambient temperature to 350 °C. Then, apply a voltage between the friction pair until the current density reaches 4 A / mm 2 (At this time, the current is 314 A). During the process, keep the rotational speed and pressure unchanged and continue to friction for 10 min. A morphology mainly dominated by friction and wear is formed on the upper surface of the disc specimen; its morphology is as Figure 2 shown.

[0042] Accumulate pictures of different pressures, different current densities, different rotational speeds, and different ambient temperatures to provide necessary conditions for subsequent reconstruction.

[0043] Example 2

[0044] First, adjust the contact pressure of the friction pair to 2 MPa. After the pressure stabilizes, start to increase the rotational speed to 4500 rpm and heat the ambient temperature to 480 °C. Then, apply a voltage between the friction pair until the current density reaches 5 A / mm 2 (At this time, the current is 392.5 A). During the process, keep the rotational speed and pressure unchanged and continue to friction for 8 min. A morphology mainly dominated by material transfer is formed on the upper surface of the disc specimen; its morphology is as Figure 3 shown.

[0045] Accumulate pictures of different pressures, different current densities, different rotational speeds, and different ambient temperatures to provide necessary conditions for subsequent reconstruction.

[0046] Example 3

[0047] First, adjust the contact pressure of the friction pair to 1.5 MPa. After the pressure stabilizes, start to increase the rotational speed to 4000 rpm and heat the ambient temperature to 350 °C. Then, apply a voltage between the friction pair until the current density reaches 7 A / mm 2 (At this time, the current is 549.5 A). During the process, keep the rotational speed and pressure unchanged. After friction for 5 min, control the distance between the friction pair to 2 mm to reach the arc starting condition. After arcing for 2 min, turn off the power supply. The rotational speed remains unchanged during the arcing process. After this experiment ends, a morphology mainly dominated by arc ablation is formed on the upper surface of the disc specimen; its morphology is as Figure 4 shown.

[0048] Accumulate pictures of different pressures, different current densities, different rotational speeds, and different ambient temperatures to provide necessary conditions for subsequent reconstruction.

[0049] Comparative Example 1

[0050] First, adjust the contact pressure of the friction pair to 0.5 MPa. After the pressure stabilizes, increase the rotational speed to 3500 rpm and heat the ambient temperature to 350 °C. Then, apply a voltage between the friction pair until the current density reaches 4 A / mm2 The process maintained the rotational speed and pressure unchanged and continued to friction for 5 minutes. As a result, the surface of the disc specimen was relatively flat, and no obvious friction and wear morphology was observed.

[0051] Comparative Example 2

[0052] First, adjust the contact pressure of the friction pair to 2 MPa. After the pressure is stable, increase the rotational speed to 4500 rpm and heat the ambient temperature to 350 °C. Subsequently, apply a voltage between the friction pairs until the current density reaches 5 A / mm 2 The process maintained the rotational speed and pressure unchanged and continued to friction for 8 minutes. A morphology mainly dominated by friction and wear was formed on the upper surface of the disc specimen, as Figure 5 shown. It can be seen from Figure 5 that the morphology of material transfer is not obvious.

[0053] Comparative Example 3

[0054] First, adjust the contact pressure of the friction pair to 1.5 MPa. After the pressure is stable, increase the rotational speed to 4000 rpm and heat the ambient temperature to 350 °C. Subsequently, apply a voltage between the friction pairs until the current density reaches 7 A / mm 2 The process maintained the rotational speed and pressure unchanged and continued to friction for 5 minutes. Then, control the distance between the friction pairs at 12 mm. A morphology mainly dominated by friction and wear was formed on the upper surface of the disc specimen, and the morphology of arc ablation was hardly visible.

Claims

1. An electromagnetic launch rail surface reconstruction method, characterized in that: Taking the electromagnetic launch armature material and the rail material as the friction pair, using a pin-on-disk friction device, introducing current to the friction pair in the pin-on-disk friction device; by changing at least one parameter among the current magnitude, the contact pressure of the friction pair, the friction speed, the friction time, and the arcing distance, obtaining the surface microstructure of the rail material under the corresponding conditions; reconstructing the surface structure of the electromagnetic launch rail based on the experimentally obtained surface microstructure; The current used is less than or equal to 1000 A; the contact pressure of the friction pair is 1.0 - 5 MPa, and the friction speed is 4000 - 7000 rpm; The surface microstructure of the rail material under the corresponding conditions includes at least one of a surface friction and wear structure, a material transfer structure, and an arc ablation structure; When an arc ablation structure is required, during arcing, control the distance between the friction pair to be 2 - 10 mm.

2. A method for reconstructing the surface of an electromagnetic launch rail according to claim 1, wherein: The current used is 200 - 600 A; The friction speed is 4000 - 6000 rpm.

3. A method for reconstructing the surface of an electromagnetic launch track according to claim 1, characterized in that: When an arc ablation structure is required, during arcing, control the distance between the friction pair to be 3 - 8 mm.

4. A method for reconstructing the surface of an electromagnetic launch track according to claim 2, characterized in that: When the rail material is CuCrZr alloy and the armature material is 7075Al alloy, The current density controlling the current-carrying friction process is 2 - 8 A / mm 2 ; Control the contact pressure of the friction pair to be 1.5 - 3 MPa; Control the friction speed to be 4000 - 6000 rpm.

5. A method for electromagnetic emission track surface reconstruction according to claim 4, characterized in that: When the rail material is CuCrZr alloy and the armature material is 7075Al alloy, control the ambient temperature to be 300 - 500 °C; this temperature can be used to compensate for the temperature during the current-carrying friction process, and the ambient temperature is heated and controlled by a resistance wire.

6. A method for electromagnetic launch track surface reconstruction according to claim 5, characterized in that: When the track material is CuCrZr alloy, the armature material is 7075Al alloy, and the current density during the current-carrying friction process is 2 - 8 A / mm 2 , the friction pair contact pressure is controlled at 1.5 - 3 MPa, and the friction speed is 4000 - 6000 rpm. After at least 4 minutes of friction, arcing occurs. When arcing occurs, the distance between the friction pair is 3 - 8 mm, and the arc ablation morphology is obtained.

7. A method for electromagnetic emission track surface reconstruction according to claim 5, characterized in that: When the track material is CuCrZr alloy, the armature material is 7075Al alloy, and the current density during the current-carrying friction process is 2 - 8 A / mm 2 , the contact pressure of the friction pair is controlled at 1.5 - 3 MPa, and the friction speed is 4000 - 6000 rpm. After friction for at least 4 minutes, the friction and wear morphology can be obtained.

8. A method for reconstructing the surface of an electromagnetic launch track according to claim 5, characterized in that: When the track material is CuCrZr alloy, the armature material is 7075Al alloy, and the current density during the current-carrying friction process is 2 - 8 A / mm 2 , the contact pressure of the friction pair is controlled at 1.5 - 3 MPa, the friction speed is 4000 - 6000 rpm, and the ambient temperature is 450 - 500 °C. After friction for at least 5 minutes, the material transfer morphology is obtained.

9. A method for electromagnetic launch rail surface reconstruction according to any one of claims 1-8, characterized in that: The current-carrying function of the pin-on-disk friction device is realized by externally adding a power supply system. After the current is generated by the power supply system, it flows into the disk specimen from one pin and then flows out from another pin specimen. The diameter of the disk specimen is 180 mm, and the pin specimen is a cylinder with a diameter of 10 mm; the material of the disk specimen is the same as the material used for the rail; the pin specimen is the material used for the armature; the pin specimen is connected to the power supply, and there is an insulating layer between the pin specimen and the pressurizing device.

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