Aluminum alloy high-pressure cylinder extrusion forming gradient heating device and heating method

Abstract

The present application relates to the technical field of aluminum alloy high-pressure gas cylinder forming, and provides an aluminum alloy high-pressure gas cylinder extrusion forming gradient heating device and a heating method, which comprises gradient heating structures, lubricating devices, molds and mold heat preservation devices arranged along the blank conveying direction respectively, further comprises temperature sensors arranged on the gradient heating structures or arranged outside for detecting temperature; the gradient heating structures comprise at least two independent temperature control zones and are distributed along the blank conveying direction; the mold heat preservation device is used for controlling the mold temperature in a preset temperature difference range with the blank temperature; through real-time temperature difference control of the mold heat preservation module and the blank temperature, the solidification or shrinkage of the lubricating film caused by excessive temperature difference when the lubricating film contacts the mold is eliminated, and meanwhile, the flexible arrangement of the gradient heating structure of the present application can meet the requirements of different temperatures in the forming process of aluminum alloy high-pressure gas cylinders with different materials and different models.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy high-pressure gas cylinder forming technology, and in particular to a gradient heating device and heating method for extrusion forming of aluminum alloy high-pressure gas cylinders. Background Technology

[0002] With the rapid development of high-pressure hydrogen storage applications such as fuel cell vehicles, unprecedented demands have been placed on the lightweight, high safety, and high reliability of aluminum alloy high-pressure cylinders. Aluminum alloy inner liners have become the mainstream choice due to their excellent specific strength. When using a hot extrusion integrated molding process, temperature control throughout the process has a significant impact on production quality. Current extrusion molding processes for aluminum alloy high-pressure cylinders generally employ a three-stage series configuration of billet heating, lubrication spraying, and die extrusion, with some insulation to minimize cooling. However, even with independent temperature control at these three stages, temperature measurement and real-time adjustments are frequently required during production.

[0003] Specifically, this involves heat loss and temperature range drift between workstations. After the billet is preheated in the furnace, it cools down during transport to the lubrication and extrusion stations due to radiation, convection, and contact heat transfer. If the temperature is too low, the lubricant cannot fully melt and spread; if the temperature is too high, it may decompose prematurely. Traditional lubrication stations typically lack active temperature control, operating only at room temperature. This results in poor film uniformity and insufficient adhesion, failing to provide continuous and effective isolation and friction reduction during subsequent high-pressure extrusion. Furthermore, the die temperature is usually preset independently and lacks real-time linkage with the billet temperature. At the moment of extrusion, a temperature difference exists between the billet and the die. When this temperature difference is significant, the high-temperature billet typically contacts the lower-temperature die, causing the surface of the billet and the attached lubricant film to solidify or shrink, leading to cracking and peeling. After lubrication failure, the aluminum alloy billet and the die steel surface directly adhere and scrape under high pressure, causing a series of problems such as die sticking, surface scratches, and drastic fluctuations in extrusion pressure. Based on this, this application proposes a gradient heating device and heating method for extruding aluminum alloy high-pressure gas cylinders, which realizes precise, coordinated and dynamic control of the temperature field throughout the process. Summary of the Invention

[0004] (a) Technical problems to be solved This invention addresses the aforementioned deficiencies in existing technologies by proposing a gradient heating device and method for extruding aluminum alloy high-pressure gas cylinders. This solution aims to overcome the problem that existing aluminum alloy extrusion molding processes cannot meet the high precision, high reliability, and high consistency requirements of high-pressure gas cylinders.

[0005] (II) Technical Solution To solve the above-mentioned technical problems, the present invention provides a gradient heating device for extrusion molding of aluminum alloy high-pressure gas cylinders, including a gradient heating structure, a lubrication device, a mold and a mold insulation device arranged along the billet conveying direction, and a temperature sensor disposed on the gradient heating structure or disposed externally for detecting temperature. The gradient heating structure includes at least two independent temperature control zones, distributed along the billet conveying direction, for real-time compensation of heat loss during billet conveying; and to stabilize the billet at the lubrication device within the optimal film-forming temperature range of the lubricant. The mold insulation device is used to control the mold temperature within a preset temperature difference range from the billet temperature.

[0006] The lubrication device is equipped with a heatable support platform and an insulation area to maintain the actual temperature of the blank after the lubricant is sprayed.

[0007] Each independent temperature control zone is equipped with an independent heating element and a temperature sensor. When the actual temperature of the billet detected by the temperature sensor is lower than the preset temperature of the billet, the heating element heats the billet.

[0008] At least one independent temperature control zone is located between the lubrication device and the mold and mold insulation device.

[0009] The heating power of the heating element can be dynamically adjusted.

[0010] The independent temperature control zone includes a first temperature control zone, which is located before the lubrication device. After the billet is preheated and discharged, it first passes through the first temperature control zone. The independent temperature control zone also includes a second temperature control zone, which is located between the lubrication device and the mold and the mold insulation device.

[0011] A gradient heating method for extruding aluminum alloy high-pressure gas cylinders includes the following steps: S1. Collect the billet discharge temperature and billet conveying speed, and dynamically adjust the heating power of each independent temperature control zone of the gradient heating structure to stabilize the actual billet temperature at the outlet of the first temperature control zone at the preset billet temperature. S2. The temperature of the insulation zone of the synchronous adjustment lubrication device is consistent with the preset temperature of the billet. Lubricant is sprayed onto the billet on the bearing platform, and then the billet is left to stand in the insulation zone to form a film. S3. The working temperature of the mold is dynamically adjusted by the mold insulation device to keep the temperature difference between the mold and the actual temperature of the lubricated billet within the allowable range, and then extrusion is carried out.

[0012] In the lubrication device, the blank is kept warm for 5 to 10 seconds after the lubricant is sprayed in the heat preservation area.

[0013] The mold insulation device aims to keep the mold's target temperature within ±30℃ of the actual temperature of the billet.

[0014] In S1, the independent temperature control zone controls the heating time of the billet based on the temperature difference between the preset temperature of the billet and the actual temperature of the billet, as well as the billet conveying speed.

[0015] (III) Beneficial Effects Compared with existing technologies, this invention achieves high-precision and high-stability temperature control throughout the extrusion process. Through the closed-loop feedback of dynamic compensation of the gradient heating structure, the temperature fluctuation of the billet entering the lubrication station can be strictly controlled, effectively solving the problems of uncontrolled temperature drop and inaccurate control of the lubrication temperature range in traditional processes. The resulting lubricating film is uniform in thickness, firmly adhered, and has excellent continuity, fundamentally reducing the risk of localized die sticking caused by uneven lubrication or insufficient adhesion, and making the initial temperature state of the entire extrusion process highly controllable.

[0016] By controlling the real-time temperature difference between the mold insulation module and the billet temperature, the solidification or shrinkage of the lubricating film caused by excessive temperature difference when the lubricating film contacts the mold is eliminated. Simultaneously, the flexible design of the gradient heating structure of this invention enables the achievement of different temperature requirements during the forming process of high-pressure gas cylinders made of different materials and models of aluminum alloy. With precise and coordinated control of the temperature field throughout the extrusion process, the plastic flow of the metal becomes more stable and uniform, helping to reduce internal stress concentration and improve the uniformity of the microstructure. This is ultimately reflected in the product, resulting in higher dimensional accuracy, more uniform wall thickness distribution, and effectively improved consistency and reliability of mechanical properties in the finished gas cylinders. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structural layout of the present invention; Detailed Implementation

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Example 1

[0019] See Figure 1 The aluminum alloy high-pressure gas cylinder extrusion molding gradient heating device provided in this embodiment includes a gradient heating structure, a lubrication device, a mold, and a mold insulation device arranged sequentially along the billet conveying direction.

[0020] The gradient heating structure comprises two independent temperature control zones, a first temperature control zone and a second temperature control zone, distributed along the billet conveying direction. The first temperature control zone is located before the lubrication device, and the billet first enters the first temperature control zone after exiting the preheating furnace. The second temperature control zone is located between the lubrication device and the mold and mold insulation device. Each independent temperature control zone is equipped with an independent heating element and a temperature sensor. The temperature sensor is located on or outside its respective temperature control zone to detect the actual temperature of the billet passing through that zone. Based on the temperature sensor readings, when the actual temperature of the billet is lower than a preset temperature, the control system controls the corresponding heating element to heat the billet, and the heating power can be dynamically adjusted to compensate for heat loss during billet conveying in real time. Through the cooperation of the first and second temperature control zones, it is ensured that the billet remains stable within the optimal temperature range of the lubricant when entering the lubrication device, and that the lubrication effect is not affected by temperature drop before leaving the lubrication device and entering extrusion. In this embodiment, the first and second temperature control zones employ electromagnetic induction heating.

[0021] The lubrication device includes a heatable support platform and a heat-insulating zone. The support platform holds the blank, and the temperature of the heat-insulating zone is adjustable to maintain the temperature of the bottom of the blank during lubricant spraying. The heat-insulating zone is a closed or semi-closed chamber, and its temperature is synchronously adjusted to match the outlet temperature of the first temperature control zone. It is used to allow the blank to stand and form a film after lubricant spraying. Preferably, the heat-insulating time lasts for 5-10 seconds to ensure that the lubricant fully melts, spreads, and adheres firmly.

[0022] In this embodiment, the mold insulation device uses electromagnetic induction heating to heat and maintain the mold. The control system collects the actual temperature of the billet at the outlet of the second temperature control zone or before it enters the mold in real time, and dynamically adjusts the heating power of the mold insulation device to keep the temperature difference between the working temperature of the mold and the actual temperature of the billet within the allowable range of ±30℃. This minimizes the temperature difference between the billet and the mold during extrusion, preventing the lubricating film from failing due to temperature shock.

[0023] This embodiment also provides a gradient heating method using the above-described device, including: S1. Collect the billet discharge temperature and billet conveying speed, and control the system to dynamically adjust the power of the heating elements in the first and second temperature control zones of the gradient heating structure. Based on the temperature difference between the preset temperature and the actual temperature of the billet and the conveying speed, control the heating time and heat of the billet so that the actual temperature of the billet after passing through the first temperature control zone stabilizes at the preset temperature.

[0024] S2. Simultaneously adjust the temperature of the insulation zone of the lubrication device to match the outlet temperature of the first temperature control zone. Place the blank on a heatable support platform for lubricant spraying, then move it into the insulation zone and let it stand for 5-10 seconds to form a film.

[0025] S3. The working temperature of the mold is dynamically adjusted by the mold insulation device to keep the temperature difference between the mold and the actual temperature of the lubricated billet within ±30℃, and then extrusion is carried out. Example 2

[0026] This embodiment is an optimization based on embodiment 1. The gradient heating structure includes multiple independent temperature control zones. This layout can achieve more precise and earlier temperature compensation for working conditions with longer conveying distances or greater thermal inertia of billets.

[0027] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An aluminum alloy high-pressure gas cylinder extrusion forming gradient heating device, characterized by, The aluminum alloy high-pressure gas cylinder extrusion molding gradient heating device includes a gradient heating structure, a lubrication device, a mold and a mold insulation device arranged along the billet conveying direction, and also includes a temperature sensor installed on the gradient heating structure or installed externally for detecting temperature. The gradient heating structure includes at least two independent temperature control zones, distributed along the billet conveying direction, for real-time compensation of heat loss during billet conveying; and to stabilize the billet at the lubrication device within the optimal film-forming temperature range of the lubricant. The mold insulation device is used to control the mold temperature within a preset temperature difference range from the billet temperature.

2. The aluminum alloy high-pressure gas cylinder extrusion forming gradient heating device according to claim 1, characterized in that, The lubrication device is equipped with a heatable support platform and an insulation area to maintain the actual temperature of the blank after the lubricant is sprayed.

3. The aluminum alloy high-pressure gas cylinder extrusion forming gradient heating device according to claim 1, characterized in that, Each independent temperature control zone is equipped with an independent heating element and temperature sensor. When the actual temperature of the billet detected by the temperature sensor is lower than the preset temperature of the billet, the heating element heats the billet.

4. The aluminum alloy high-pressure gas cylinder extrusion forming gradient heating device according to claim 3, characterized in that, At least one independent temperature control zone is set between the lubrication device and the mold and mold insulation device.

5. The aluminum alloy high-pressure gas cylinder extrusion forming gradient heating device according to claim 3, characterized in that, The heating power of the heating element can be dynamically adjusted.

6. The gradient heating device for extrusion molding of aluminum alloy high-pressure gas cylinders as described in claim 3, characterized in that, The independent temperature control zone includes a first temperature control zone, which is located before the lubrication device. After the billet is preheated and discharged, it first passes through the first temperature control zone. The independent temperature control zone also includes a second temperature control zone, which is located between the lubrication device and the mold and the mold insulation device.

7. A gradient heating method for extrusion molding of aluminum alloy high-pressure gas cylinders, characterized in that, The aluminum alloy high-pressure gas cylinder extrusion molding gradient heating device according to any one of claims 1 to 6 includes the following steps: S1. Collect the billet discharge temperature and billet conveying speed, and dynamically adjust the heating power of each independent temperature control zone of the gradient heating structure to stabilize the actual billet temperature at the outlet of the first temperature control zone at the preset billet temperature. S2. The temperature of the insulation zone of the synchronous adjustment lubrication device is consistent with the preset temperature of the billet. Lubricant is sprayed onto the billet on the bearing platform, and then the billet is left to stand in the insulation zone to form a film. S3. The working temperature of the mold is dynamically adjusted by the mold insulation device to keep the temperature difference between the mold and the actual temperature of the lubricated billet within the allowable range, and then extrusion is carried out.

8. The gradient heating method for extrusion molding of aluminum alloy high-pressure gas cylinders as described in claim 7, characterized in that, In the lubrication device, the blank is kept warm for 5 to 10 seconds after the lubricant is sprayed in the heat preservation area.

9. The gradient heating method for extrusion molding of aluminum alloy high-pressure gas cylinders as described in claim 7, characterized in that, The mold insulation device controls the temperature difference between the mold and the actual temperature of the billet to be within ±30℃.

10. The gradient heating method for extrusion molding of aluminum alloy high-pressure gas cylinders as described in claim 7, characterized in that, In S1, the independent temperature control zone controls the heating time of the billet based on the temperature difference between the preset temperature of the billet and the actual temperature of the billet, as well as the billet conveying speed.

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