A method for preparing multi-performance suspension materials with the assistance of electric pulses

Abstract

The present invention belongs to the field of automobile manufacturing technology, and specifically relates to a method for preparing multi-performance suspension materials with electric pulse assistance, the steps of which are: determining the respective electrical conductivity of the two plates to be composited; introducing one end of the two plates between the two rollers of a two-roll mill; starting the electric pulse assisted heating device to heat the contact portion of the two plates, and the two rollers of the two-roll mill drive the two plates to move forward, and when the tail end of the shorter plate passes through the closest point between the two rollers, the two-roll mill and the electric pulse assisted heating device are turned off. In the process of preparing composite plates based on this process method, local heating of the deformation zone joint tip can be achieved instead of overall heating. The process method can achieve controllable heating temperature, and can prepare composite plates with higher bonding strength, so that the composite material has multiple performance characteristics such as high strength, light weight, and fast thermal conductivity, thereby strengthening the function of the suspension system and improving NVH performance.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile manufacturing, and in particular relates to a method for preparing a multi-performance suspension material with the assistance of electric pulses. Background Art

[0002] With the rapid development of the automotive industry, end customers are not only concerned about the technical characteristics of vehicle configurations, but also about vehicle technical production processes and methods. In particular, green production processes and methods have become the main theme of development, which not only saves human resource costs but also improves production efficiency. The suspension system, as a device for vibration reduction, limiting and connection between the vehicle powertrain and the frame or body, plays an important role in affecting the NVH performance of the vehicle. However, the homogeneous materials used in the inner and outer jackets of the suspension can no longer meet the needs of high-quality development and should be developed in the direction of composite materials. Therefore, new preparation processes for composite materials have become a research focus and hot topic.

[0003] like Figure 1 The figure shows a common hot-rolling process for composite plates, consisting of a heating device 01, a base plate 02, and a rolling mill 03. During operation, the heating device heats the base plate, and once it reaches a certain temperature, the plate is fed into the rolling mill to produce a composite material. In existing technologies, the base plate is heated as a whole, and rolling begins only after the upper and lower surfaces of the plate reach a set temperature. This results in the upper and lower surfaces of the base plate being susceptible to oxidation when exposed to air before rolling, affecting the properties of the contact surfaces and limiting the efficiency of composite plate production. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing multi-performance suspension materials with the assistance of electric pulses. Under the premise of ensuring the bonding performance of the composite material, local heating is performed in the deformation area of ​​the plate to replace the overall heating, thereby avoiding large-area oxidation of the surface of the elementary plate and improving the bonding performance of the composite plate.

[0005] To achieve the above objectives, this application is implemented through the following technical solutions:

[0006] A method for preparing a multi-performance suspension material with the assistance of electric pulses, comprising the following steps:

[0007] S1. Determine the electrical conductivity of the two sheets to be composited;

[0008] S2, the length of the plate with a low conductivity coefficient in the rolling direction during cutting is greater than the length of the plate with a high conductivity coefficient;

[0009] S3, placing the two plates one above the other, and introducing one end of the two plates between the two rolls of a two-roll mill;

[0010] S4. Start the electric pulse auxiliary heating equipment to heat the contact part of the two plates. The two rollers of the two-roll mill drive the two plates to move forward. When the tail end of the shorter plate passes through the closest point between the two rollers, turn off the two-roll mill and the electric pulse auxiliary heating equipment.

[0011] Furthermore, an introduction part is provided at the front end of each of the two plates, and when the introduction part is introduced between the two rollers of the two-roller rolling mill, the electric pulse auxiliary heating device is started.

[0012] Furthermore, after the guide is introduced between the two rolls of the two-roll mill, the two rolls of the two-roll mill stop rotating for a set time, and after the electric pulse assisted heating equipment heats the contact part of the two plates to a set temperature, the two rolls of the two-roll mill continue to rotate.

[0013] Furthermore, the length S of the introduction portion is set according to the time t required for the electric pulse device to start heating until the temperature of the contact portion of the two plates reaches the rolling temperature×the speed v at which the two rollers drive the plates forward.

[0014] Furthermore, the electric pulse assisted heating device includes an electric pulse heating device, a first wire and a second wire, one end of the first wire is connected to the positive pole of the electric pulse heating device, and the other end is connected to the tail end of the plate with a small conductivity coefficient; one end of the second wire is connected to the lower roller of the two rollers of the two-roll rolling mill, and the other end is connected to the negative pole of the electric pulse heating device.

[0015] Furthermore, the first wire is connected to the tail end of the plate with a low conductivity coefficient through a connector.

[0016] Furthermore, the connecting member is a bolt or a clamping member.

[0017] Furthermore, if the connecting member is a bolt, a threaded hole is provided at the tail of the plate with a low conductivity coefficient.

[0018] The beneficial effects of the present invention are:

[0019] In the process of preparing composite plates based on this process method, local heating of the deformation zone bonding tip can be achieved instead of overall heating. The process method can control the heating temperature and can prepare composite plates with higher bonding strength, so that the composite materials have multiple performance characteristics such as high strength, light weight, and fast thermal conductivity, thereby enhancing the function of the suspension system and improving the NVH performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the hot rolling process of composite plates in existing technology.

[0021] Figure 2 Schematic diagram of the hot rolling process of the composite plate of the present invention.

[0022] Figure 3 This is the current distribution diagram of the pulse current passing through the deformation zone of the composite plate.

[0023] Figure 4 This is the current change diagram of the composite plate deformation zone after the pulse current ends.

[0024] Figure 5 This is the overall temperature distribution of the composite plate during the pulse current heating process.

[0025] Figure 6 This is the overall temperature distribution curve of the composite plate during the pulse current heating process.

[0026] Figure 7 Schematic diagram of current flow during pulse current heating process.

[0027] Description of reference numerals:

[0028] 01. Heating equipment; 02. Elementary plate; 03. Rolling mill equipment; 1. Two-roll rolling mill; 2. Composite plate; 3. Second conductor; 4. Pulse auxiliary heating equipment; 5. Bolts; 11. Roller; 21. Copper plate; 22. Aluminum plate. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is described in detail below with reference to the accompanying drawings. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solution of the present invention, and cannot be interpreted as limiting the technical solution of the present invention.

[0030] like Figure 2 and Figure 7 As shown, the present application relates to a method for preparing multi-performance suspension materials with the assistance of electric pulses. In the present technology, the rolling mill used in the composite plate rolling process is a two-roll mill 1. Because the two-roll mill is a commonly used equipment in the field, the applicant does not explain the structure of the two-roll mill. The technical personnel in this field can make a choice according to actual needs, and it will not affect the realization of the technical solution of the present application.

[0031] This technical solution focuses on the rolling process, eliminating the conventional heating equipment used in composite rolling. Specifically, the composite rolling process does not heat the entire or extensive surface of the rolled sheet. To mitigate surface oxidation during composite rolling, this solution utilizes the characteristics of electrical pulse discharge and its microscopic sensitivity to metal materials to locally heat the two sheets being composited, creating a temperature gradient across the surface.

[0032] The processing technology of this application specifically adopts the following steps:

[0033] S1. Determine the electrical conductivity of the two plates to be composited. In actual production, the materials of the two plates to be composited are usually different, and the composite plates of this technical solution are all made of metal, and do not involve the composite of metal plates and other non-metallic plates.

[0034] S2. The length of the sheet with lower conductivity in the rolling direction during cutting is greater than the length of the sheet with higher conductivity. Specifically, the sheet with lower conductivity is placed above the sheet with higher conductivity. The technical solution of this application is illustrated using the example of cladding a copper sheet 21 and an aluminum sheet 22, where the copper sheet has lower conductivity than the aluminum sheet. In this embodiment, both sheets to be clad are rectangular, where the length of the sheet with lower conductivity is greater than the length of the aluminum sheet.

[0035] In other embodiments of the present application, an introduction part is further provided at the front end of the two plates, which is used to introduce the two plates into between the two rollers 11 of the two-roll mill 1. In other embodiments of the present application, because the opposite surfaces of the two plates need to be rolled together, and the pulse-assisted heating equipment needs to perform several current pulses to heat the surfaces of the contact points of the two plates to the set temperature, an introduction part is introduced for this purpose. When the introduction parts of the two plates pass through the two rollers of the two-roll mill, the pulse-assisted heating equipment 4 heats the contact points to reach the rolling temperature.

[0036] The length S of the introduction portion is set according to the time t required for the electric pulse assisted heating device to start heating until the temperature of the contact portion of the two plates reaches the rolling temperature×the speed v at which the two rollers 11 drive the plates forward.

[0037] In other embodiments of the present application, the material waste during the rolling process can be reduced by not using the lead-in part, thereby reducing the problem of increased material costs caused by shearing the lead-in part after the composite is completed.

[0038] S3. Place the two plates one above the other and introduce one end of the two plates between the two rollers 11 of the two-roller rolling mill.

[0039] S4. Start the electric pulse auxiliary heating equipment to heat the contact part of the two plates. The two rollers of the two-roll mill drive the two plates to move forward. When the tail end of the shorter plate passes through the closest point between the two rollers, turn off the two-roll mill and the pulse auxiliary heating equipment 4.

[0040] In other embodiments of the present application, because no introduction part is provided for the two plates, waste of material can be avoided, and after the plates to be composited are introduced between the two rollers of the two-roll mill, the two rollers of the two-roll mill stop rotating for a set time, and after the pulse auxiliary heating device 4 heats the contact parts of the two plates to a set temperature, the two rollers 11 of the two-roll mill continue to rotate.

[0041] like Figure 7 As shown, the electric pulse assisted heating device of the present application includes an electric pulse heating device, a first wire, and a second wire. One end of the first wire is connected to the positive electrode of the electric pulse heating device, and the other end is connected to the tail end of the plate with a low conductivity coefficient. One end of the second wire 3 is connected to the lower roller of the two rollers of the two-roll mill, and the other end is connected to the negative electrode of the electric pulse heating device. The first wire is connected to the tail end of the plate with a low conductivity coefficient via a connector; the connector is a bolt or a clamp. If the connector is a bolt 5, a threaded hole is provided at the tail end of the plate with a low conductivity coefficient.

[0042] Working principle:

[0043] In the rolling process of composite plates, the deformation bonding area of ​​composite rolling is actually very small, and physical means cannot achieve the expected measurement target. In addition, the pulse discharge duration (pulse width) is only tens of microseconds, which also restricts the implementation of actual observation. Therefore, with the help of simulation software to illustrate the temperature gradient formation process, the electrothermal coupling pre-treatment method of the deformation zone is adopted, and the two plates are connected to the square wave pulse with parameters of 365V-500Hz-80μs. When the pulse discharges, the current flows through the deformation zone of the composite plate, and obvious current concentration appears in the bonding area, forming a disturbance effect. The maximum regional current density is 1.16×1012A / m2, as shown in Figure 2. Figure 3 At the end of the pulse discharge, the current in the entire composite plate deformation zone disappears, and the variable flow effect disappears as well, as shown in Figure 4 As shown. When a pulse is applied for a certain time, the temperature of the deformation zone will rise rapidly during discharge in a single cycle, and then drop immediately when the discharge ends. The temperature drop rate is slower than the rise rate. Under the continuous action of multiple pulse cycles, the temperature of the joint gradually increases. At 0.4s, the maximum temperature of the deformation zone can reach 85.4℃, while the temperature from the composite plate rolling entrance to the tail is still at room temperature, forming a temperature gradient, achieving the effect of preheating only the deformation zone, as shown. Figure 5 and Figure 6 shown.

[0044] In order to improve the bonding performance of the composite sheet 2, the temperature of the deformation zone is reasonably controlled by adjusting the voltage, frequency, and pulse width of the electric pulse device. In this embodiment, the positive electrode of the pulse power supply is connected to the copper plate. The pulse current with the parameters of 365V-700Hz-70μs flows from the copper plate to the aluminum plate in the common plastic forward sliding zone of the deformation zone. Then the current flows from the aluminum plate to the lower roller of the two-roll mill, and finally flows out to the bearing seats at both ends and connects to the negative electrode of the pulse current, forming a complete working circuit. Figure 7It should be noted that near the end of rolling, the rolling mill and pulse power supply were immediately turned off, the copper wires connected by bolts were manually removed, and the composite plate rolled specimen was removed. The maximum temperature of the deformation zone was measured by experimental methods to be approximately 295.5°C, and the peel strength was 6.69N / mm.

[0045] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A method for preparing a multi-performance suspension material with the aid of electric pulses, characterized in that: Use the following steps: S1. Determine the electrical conductivity of the two sheets to be composited; S2, the length of the plate with a low conductivity coefficient in the rolling direction during cutting is greater than the length of the plate with a high conductivity coefficient; S3, placing the two plates one above the other, and introducing one end of the two plates between the two rolls of a two-roll mill; S4. Starting the electric pulse auxiliary heating device to heat the contact portion of the two plates. The two rollers of the two-roll mill drive the two plates to move forward. When the tail end of the shorter plate passes the closest point between the two rollers, the two-roll mill and the electric pulse auxiliary heating device are turned off. The electric pulse assisted heating device includes an electric pulse heating device, a first wire and a second wire, one end of the first wire is connected to the positive pole of the electric pulse heating device, and the other end is connected to the tail end of the plate with a small conductivity coefficient; one end of the second wire is connected to the lower roller of the two rollers of the two-roll rolling mill, and the other end is connected to the negative pole of the electric pulse heating device.

2. The method for preparing multi-performance suspension materials with electric pulse assistance according to claim 1, characterized in that: An introduction part is provided at the front end of the two plates. When the introduction part is introduced between the two rollers of the two-roller rolling mill, the electric pulse auxiliary heating device is started.

3. The method for preparing multi-performance suspension materials with electric pulse assistance according to claim 2, characterized in that: The length S of the introduction portion is set based on the time t required for the electric pulse device to start heating until the temperature of the contact portion of the two plates reaches the rolling temperature × the speed v at which the two rollers drive the plates forward.

4. The method for preparing multi-performance suspension materials with electric pulse assistance according to claim 1, characterized in that: After the plate is introduced between the two rollers of the two-roll mill, the two rollers of the two-roll mill stop rotating for a set time. After the electric pulse auxiliary heating equipment heats the contact part of the two plates to the set temperature, the two rollers of the two-roll mill continue to rotate.

5. The method for preparing multi-performance suspension materials with electric pulse assistance according to claim 1, characterized in that: The first wire is connected to the tail end of the plate with a low conductivity coefficient through a connecting piece.

6. The method for preparing multi-performance suspension materials with electric pulse assistance according to claim 5, characterized in that: The connecting piece is a bolt or a clamp.

7. The method for preparing multi-performance suspension materials with electric pulse assistance according to claim 6, characterized in that: If the connecting piece is a bolt, a threaded hole is provided at the tail of the plate with a low conductivity coefficient.

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