Aluminum alloy electric auxiliary forming and electric pulse solid solution aging integrated manufacturing device and method

Abstract

The invention relates to an aluminum alloy electric auxiliary forming and electric pulse solid solution aging integrated manufacturing device and method, and the aluminum alloy electric auxiliary forming and electric pulse solid solution aging integrated manufacturing device comprises a stretch bending die, a pulse power supply, a temperature monitoring device and a cooling device, the pulse power supply outputs a plurality of groups of parallel electrode pairs which are sequentially and symmetrically arranged on the two sides of the aluminum alloy profile, the temperature monitoring device collects temperature signals of a plurality of positions on the aluminum alloy profile, and the cooling device is arranged on the stretch bending die and is used for cooling in a spraying mode. According to the method, electric auxiliary stretch-bending forming and solid solution aging treatment are combined, the comprehensive performance of the aluminum alloy stretch-bending part is improved, and therefore the part with the forming precision and the performance meeting the requirements is obtained, the complexity of the heat treatment process of the stretch-bending part is simplified, and the manufacturing period is shortened.

Description

Technical Field

[0001] The present invention relates to a technology in the field of alloy manufacturing, specifically to an integrated manufacturing device and method for electric-assisted forming and electric-pulse solid solution aging of aluminum alloy. Background Art

[0002] Aluminum alloy has many excellent properties, so it is widely used in structural parts of automobiles, aviation, aerospace, etc. Structural parts made of aluminum alloy can not only meet the requirements of strength and rigidity, but also greatly reduce the overall weight. Due to the high strength and hardness of aluminum alloy and poor elongation, it will produce large springback and error during forming. For aluminum alloy bending forming structural parts, improving plasticity and reducing forming error are key factors affecting processing quality. Summary of the invention

[0003] The present invention aims to improve the forming accuracy by improving the mold structure or pre-treating the aluminum alloy, but the processing flow is relatively complicated, the processing cycle is long, and a large amount of springback compensation is required after stretching and bending, and the aluminum alloy profile cannot be accurately processed in a single process. The present invention proposes an integrated manufacturing device and method for electric-assisted forming and electric pulse solution aging of aluminum alloy, which combines electric-assisted stretch-bending forming with solution aging treatment to improve the comprehensive performance of aluminum alloy stretch-bent parts, thereby obtaining parts with forming accuracy and performance that meet the requirements, and simplifying the complexity of the heat treatment process of the stretch-bent parts, thereby shortening the manufacturing cycle.

[0004] The present invention is achieved through the following technical solutions:

[0005] The present invention relates to an integrated manufacturing device for aluminum alloy electric-assisted forming and electric pulse solution aging, comprising: a drawing and bending die, a pulse power supply, a temperature monitoring device and a cooling device, wherein: the two ends of the aluminum alloy profile are respectively connected to the drawing and bending die and the middle part is in contact with the drawing and bending die, the pulse power supply outputs multiple groups of parallel electrode pairs and is symmetrically arranged on both sides of the aluminum alloy profile in sequence, the temperature monitoring device collects temperature signals at several positions on the aluminum alloy profile, and the cooling device is arranged on the drawing and bending die and cools down by spraying.

[0006] The stretch-bending die comprises: a forming die and a pair of stretch-bending machine arms rotatably arranged thereon, the stretch-bending machine arms are respectively connected to the two ends of the aluminum alloy profile, the forming die contacts the middle part of the aluminum alloy profile, and the forming die bends the aluminum alloy profile through the relative rotation of the stretch-bending machine arms.

[0007] The present invention relates to an integrated manufacturing method of aluminum alloy electric-assisted forming and electric pulse solid solution aging based on the above device, comprising:

[0008] Step 1) Electric-assisted stretch bending: Load the aluminum alloy profile on the clamps at both ends of the stretch bending machine, and clamp the input / output electrodes and temperature sensor wires on the aluminum alloy profile in turn, set up the liquid nitrogen cooling equipment, set the initial current density and forming temperature, start the pulse power supply to power on and heat up, and start the stretch bending machine after the overall temperature of the profile stabilizes near the forming temperature to start stretch bending. After the forming is completed, turn off the stretch bending machine.

[0009] Step 2) Electric pulse solution treatment: Keep the position of the bent part on the die unchanged, set the solution treatment temperature, and continue to heat the bent part with electricity. When the temperature of the bent part reaches the solution temperature, the pulse power supply will automatically reduce the input current to keep the bent part within the solution temperature range, and then perform solution treatment on the bent part for a certain period of time.

[0010] Step 3) Cooling and quenching: After the solution treatment is completed, the quenching temperature is set, and the liquid nitrogen cooling equipment is turned on at the same time. Liquid nitrogen is sprayed on the surface of the bent part to quickly cool it to the quenching temperature range for cooling and quenching.

[0011] Step 4) Electric pulse aging treatment: After the quenching treatment is completed, the aging treatment temperature is set, and the pulse power supply automatically increases the current density to energize and heat the bent parts. When the bent parts reach the quenching temperature, the power supply system automatically adjusts the current density to keep the temperature of the bent parts within the aging temperature range, and then performs aging treatment for a certain period of time. After the aging treatment is completed, the pulse power supply is turned off, and the bent parts are unloaded and removed after natural cooling. Technical Effects

[0012] The present invention can complete multiple processing steps such as drawing and bending forming and solid solution aging treatment of aluminum alloy profiles on a set of equipment; reduce the flow stress of aluminum alloy profiles, improve material plasticity, and reduce springback after forming through the electroplasticity of pulse current; use the Joule heating effect of pulse current to quickly heat the profiles and promote the solid solution aging treatment process of the drawn and bent parts; and achieve precise control of the profile temperature through the technical method of multi-zone power-on temperature control. Compared with the prior art, the present invention does not require multiple loading and unloading of profiles, and the bending and heat treatment processes of the profiles can be completed on the same set of equipment, thereby simplifying the processing flow; the heating by electric current greatly shortens the heating time and improves the efficiency of heat processing; during the operation, it is only necessary to set the temperature of each processing step, and the control system will automatically adjust the input current according to the temperature change of the profile, so that the temperature of the bent part can quickly reach and stabilize within the processing temperature range; through multi-zone power-on temperature control technology, the temperature of each area of ​​the bent part can be detected in real time during the processing, and the heating rate of different areas can be accurately adjusted according to the temperature change, so as to achieve precise control of the temperature, prevent local overheating or temperature concentration of the workpiece, and enable the bent part to maintain overall temperature balance during the processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the integrated manufacturing device for electric-assisted forming and electric pulse solution aging of aluminum alloy of the present invention;

[0014] In the figure: 1 bending machine arm, 2 input / output electrode, 3 forming die, 4 aluminum alloy profile, 5 temperature sensor, 6 liquid nitrogen nozzle, 7 bending machine fixture, 8 pulse power supply, 9 temperature monitoring device, 10 liquid nitrogen cooling device;

[0015] Figure 2 It is a schematic diagram of the working example. DETAILED DESCRIPTION

[0016] like Figure 1 As shown, the aluminum alloy electric-assisted forming and electric pulse solution aging integrated manufacturing device involved in this embodiment includes: a stretching and bending die, a pulse power supply 8, a temperature monitoring device and a cooling device, wherein: the two ends of the aluminum alloy profile 4 are respectively connected to the stretching and bending die and the middle part is in contact with the stretching and bending die, the pulse power supply 8 outputs multiple groups of 2 pairs of parallel electrodes and is symmetrically arranged on both sides of the aluminum alloy profile 4 in sequence, the temperature monitoring device collects temperature signals at several positions on the aluminum alloy profile 4, and the cooling device is arranged on the stretching and bending die and cools down by spraying.

[0017] The stretch-bending die comprises: a forming die 3 and a pair of stretch-bending machine arms 1 rotatably arranged thereon, the stretch-bending machine arms 1 are respectively connected to the two ends of the aluminum alloy profile 4, the forming die 3 is in contact with the middle part of the aluminum alloy profile 4, and the forming die 3 achieves 30° bending of the aluminum alloy profile 4 through the relative rotation of the stretch-bending machine arms 1.

[0018] Insulating gaskets are provided between the draw-bending machine pivot arm 1 and the aluminum alloy profile 4 and between the forming die 3 and the draw-bending machine pivot arm 1 .

[0019] There are five pairs of electrode pairs 2 in total.

[0020] The temperature monitoring device comprises four groups of temperature sensors 6 and temperature monitors 9 connected thereto.

[0021] The 7075 aluminum alloys involved in this embodiment are all industrial profiles.

[0022] Step 1) Profile pretreatment: The selected 7075 aluminum alloy profile has a length of 1m, a thickness of 10mm, and a T-shaped cross-section. The profile surface, especially the surfaces at both ends in contact with the bending machine fixture and the power chuck, is polished with sandpaper to remove surface impurities and obtain a clean and smooth surface.

[0023] Step 2) Electric-assisted stretch-bending: Load the aluminum alloy profile on the stretch-bending machine, clamp the input / output electrodes and temperature sensors at different parts of the profile, set the forming temperature and the initial output current, the forming temperature is 180°C, the initial output current of each pair of electrodes is 200A, start the pulse power supply and the temperature monitoring device to start heating. During the heating process, the heating rate in the middle area of ​​the profile is higher, so the control system will automatically reduce the input current on both sides of the profile to keep the overall temperature of the profile consistent. After the overall temperature of the profile stabilizes at around the forming temperature, start the stretch-bending machine to start stretch-bending. After the forming is completed, turn off the stretch-bending machine and the pulse power supply.

[0024] Step 3) Electric pulse solution treatment: After the bending is completed, the solution treatment temperature is set to 450°C, and the pulse power supply is restarted to heat the bent part. When the temperature of the bent part reaches 450°C, the control system automatically adjusts the input current of each area to stabilize the overall temperature of the bent part within the solution temperature range, and then maintains the bent part at this temperature for 40 minutes of solution treatment. After the solution treatment is completed, the pulse power supply is turned off.

[0025] Step 4) Cooling and quenching: After the solution treatment is completed, open the liquid nitrogen nozzle and evenly spray liquid nitrogen on each area of ​​the bent part to quickly reduce its temperature to about room temperature 25°C to complete cooling and quenching.

[0026] Step 5) Electric pulse aging treatment: After quenching treatment, the aging temperature is set to 180°C, and the pulse power supply is started to continue to heat the bent parts. When the overall temperature of the bent parts is stabilized at around 180°C, the bent parts are aged for 3 hours at this temperature. After the treatment is completed, the pulse power supply is turned off, and the bent parts are removed after natural cooling.

[0027] Comparative Example 1

[0028] In contrast, when the aluminum alloy profile is subjected to stretch bending and solution aging treatment, the stretch bent parts are heated to the corresponding processing temperature (the average heating rate will not exceed 30°C / min) in a heat treatment furnace before processing.

[0029] Compared with comparative example 1, the springback angle of the bent part after forming by the method of the present invention is only about 5°, while the springback angle of the bent part heated by the heat treatment furnace reaches 10°; the heating time to reach the solution temperature range of the present invention is 1 hour shorter than the heating time in the heat treatment furnace, and the heating time to reach the aging temperature range is 30 minutes shorter than the heating time in the heat treatment furnace; under the same mechanical property index requirements, the solution treatment time in the present invention is 2 hours shorter than that in comparative example 1, and the aging treatment time is 4 hours shorter than that in comparative example 1, and the time required for the entire heat treatment process is shortened by 6 to 7 hours, thereby greatly improving the processing efficiency.

[0030] Compared with the prior art, the present invention improves the plasticity of aluminum alloy through electric-assisted processing, significantly reduces the degree of springback of bent parts, and controls the springback angle after forming within 5°; the pulse current directly heats the blank, and the energy utilization efficiency is high; the heating rate is increased by electric current heating, and the solution aging treatment process is promoted; after each process is completed, only the processing temperature of the next process needs to be set, and the system will automatically adjust the current size to make the profile temperature reach the processing temperature range, which greatly simplifies the user's operation process.

[0031] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. An integrated manufacturing device for electric-assisted forming and electric pulse solution aging of aluminum alloy, characterized in that: include: A drawing and bending die, a pulse power supply, a temperature monitoring device and a cooling device, wherein: the two ends of the aluminum alloy profile are respectively connected to the drawing and bending die and the middle part is in contact with the drawing and bending die, the pulse power supply outputs multiple sets of parallel electrode pairs and are symmetrically arranged on both sides of the aluminum alloy profile in sequence, the temperature monitoring device collects temperature signals at several positions on the aluminum alloy profile, and the cooling device is arranged on the drawing and bending die and cools down by spraying.

2. The aluminum alloy electric-assisted forming and electric pulse solution aging integrated manufacturing device according to claim 1 is characterized in that: The stretch-bending die comprises: a forming die and a pair of stretch-bending machine arms rotatably arranged thereon, the stretch-bending machine arms are respectively connected to the two ends of the aluminum alloy profile, the forming die contacts the middle part of the aluminum alloy profile, and the forming die bends the aluminum alloy profile through the relative rotation of the stretch-bending machine arms.

3. The aluminum alloy electric-assisted forming and electric pulse solution aging integrated manufacturing device according to claim 1 is characterized in that: Insulating gaskets are arranged between the rotating arm of the stretch-bending machine and the aluminum alloy profile, and between the forming die and the rotating arm of the stretch-bending machine.

4. A method for manufacturing aluminum alloy by electric assisted forming and electric pulse solution aging based on the device described in any one of claims 1 to 3, characterized in that: include: Step 1) Electric-assisted bending: The aluminum alloy profile is loaded on the clamps at both ends of the bending machine, and the input / output electrodes and the temperature sensor wires are clamped on the aluminum alloy profile in sequence, the liquid nitrogen cooling equipment is set up, the initial current density and the forming temperature are set, the pulse power supply is started to power on and heat up, and the bending machine is started to start bending after the overall temperature of the profile is stabilized near the forming temperature, and the bending machine is closed after the forming is completed; Step 2) Electric pulse solution treatment: Keep the position of the bent part on the die unchanged, set the solution treatment temperature, and continue to heat the bent part with electricity. After the temperature of the bent part reaches the solution temperature, the pulse power supply will automatically reduce the input current to keep the bent part within the solution temperature range. Then, the bent part is subjected to solution treatment for a certain period of time. Step 3) Cooling and quenching: After the solution treatment is completed, the quenching temperature is set, and the liquid nitrogen cooling equipment is turned on at the same time, and liquid nitrogen is sprayed on the surface of the bent part to quickly cool it to the quenching temperature range for cooling and quenching; Step 4) Electric pulse aging treatment: After the quenching treatment is completed, the aging treatment temperature is set, and the pulse power supply automatically increases the current density to power on and heat the bent parts. After the bent parts reach the quenching temperature, the power supply system automatically adjusts the current density to keep the temperature of the bent parts within the aging temperature range. Then, the aging treatment is carried out for a certain period of time. After the aging treatment is completed, the pulse power supply is turned off, and the bent parts are unloaded and removed after natural cooling.

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