A green cyclic preparation method for rapid oil removal annealing of aluminum alloy coiled material

Abstract

The present application relates to a kind of green cycle preparation methods of aluminum alloy coil quick oil removal annealing, including annealing furnace connected with vacuum pump, and preparation method is as follows: after cold rolling, aluminum alloy coil is sent into annealing furnace, after annealing furnace is evacuated, make air pressure in annealing furnace at 0~10pa, ensure that the pressure in the process of oil removal annealing is in the vacuum state of 0~10pa;Annealing furnace is heated to 90~120 degrees Celsius and is kept for 10h or more, in the process of keeping, open vacuum pump, exhaust gas generated in annealing furnace is extracted to the recovery tray outside annealing furnace, the liquid part recovered can be recycled for cold rolling, and annealing furnace is treated to aluminum alloy coil for oil removal annealing.By increasing the temperature of aluminum coil to a certain temperature under vacuum, the rolling oil on the surface of the aluminum coil is volatilized, and the rolling oil is recycled for use, effectively improving the shortcomings of traditional preparation methods, improving the efficiency and effect of oil removal annealing, and realizing low-carbon green environmental protection, rolling oil recycling, making production cost and efficiency more advantageous.

Description

Technical fields:

[0002] This invention belongs to the field of aluminum alloy strip degreasing and annealing technology, and particularly relates to a green and circular preparation method for rapid degreasing and annealing of aluminum alloy coils. Background technology:

[0004] After rolling, aluminum alloy coils often have a significant amount of residual rolling oil on their surface. This is typically addressed by cleaning with deionized water, alkaline solutions, or acidic solutions, followed by annealing in a protective atmosphere furnace to improve surface smoothness and prevent annealing oil spots. However, improper cleaning or annealing of the aluminum coil can lead to the sintering of this rolling oil after high-temperature treatment, resulting in surface oil spots. Currently, some methods involve pre-annealing degreasing, such as raising the furnace temperature to 180 degrees Celsius and holding it for 2–8 hours before the coil reaches the annealing temperature. While this method can remove oil, it is prone to ineffective degreasing and can cause the aluminum temperature to exceed the stabilization annealing temperature (generally above 120 degrees Celsius), negatively impacting the material's ideal properties.

[0005] Therefore, it is necessary to improve the aforementioned technical issues, hence this case. Summary of the Invention:

[0007] This invention addresses the problems of the prior art by providing a green and recyclable preparation method for rapid degreasing and annealing of aluminum alloy coils.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a green and cyclical preparation method for rapid degreasing and annealing of aluminum alloy coils, wherein the cold-rolled aluminum alloy coils are fed into an annealing furnace, the annealing furnace is evacuated, the annealing furnace is heated to 90-120 degrees Celsius and held at that temperature for more than 10 hours, and the annealing furnace performs degreasing and annealing treatment on the aluminum alloy coils.

[0009] Furthermore, after the annealing furnace is evacuated, the air pressure inside the annealing furnace is between 0 and 10 Pa, ensuring that the pressure is in a vacuum state of 0 to 10 Pa during the degreasing annealing process.

[0010] Furthermore, the annealing furnace is connected to a vacuum pump; during the heat preservation process, the vacuum pump is turned on to draw the waste gas generated in the annealing furnace to the recovery tray outside the annealing furnace, and the recovered liquid portion can be recycled again for cold rolling.

[0011] Furthermore, the annealing furnace is a vacuum-capable box-type or bell-type annealing furnace.

[0012] Compared with the prior art, the present invention has the following advantages: The present invention is reasonably designed. By raising the temperature of the aluminum coil to a certain temperature under vacuum, the rolling oil on the surface of the aluminum coil can be volatilized and recycled. This effectively improves the shortcomings of traditional preparation methods, improves the efficiency and effect of degreasing and annealing, and achieves low carbon and green environmental protection. The recycling of rolling oil makes production cost and efficiency more advantageous. Detailed implementation method:

[0014] The present invention will now be described in further detail with reference to specific embodiments.

[0015] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientation or positional relationship only for the convenience of describing this invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0016] This invention discloses a green and circular preparation method for rapid degreasing and annealing of aluminum alloy coils, comprising a vacuum-capable annealing furnace connected to a vacuum pump. The annealing furnace is evacuated by the vacuum pump. The method is as follows: the cold-rolled aluminum alloy coil is fed into a vacuum-capable box-type or bell-type annealing furnace. After evacuating the annealing furnace, the air pressure inside the furnace is maintained at 0-10 Pa to ensure a vacuum state of 0-10 Pa during the degreasing and annealing process. The annealing furnace is heated to 90-120 degrees Celsius and held at that temperature for more than 10 hours. During the holding process, the vacuum pump is turned on to pump the waste gas generated inside the annealing furnace to a recovery tray outside the furnace. The recovered liquid portion can be recycled again for cold rolling. The annealing furnace performs degreasing and annealing treatment on the aluminum alloy coil. This method employs vacuum degreasing annealing, combined with low-temperature long-term heat preservation and air extraction, effectively overcoming the problem of annealing oil spots that are easily generated during the current coil annealing process. It breaks with conventional preparation processes, greatly improves the surface quality of aluminum alloy coils, shortens the process flow, and increases operating efficiency.

[0017] In this embodiment, the annealing furnace is a box-type or bell-type annealing furnace.

[0018] Working principle explanation:

[0019] (1) In order to ensure the rapid degreasing and green recycling of aluminum alloy coils, the annealing furnace can be vacuumed to ensure that the pressure during the degreasing process is in a vacuum state of 0-10pa. If the pressure is higher than this, the degreasing effect will not be achieved, or the degreasing will be incomplete, resulting in annealing oil spot defects.

[0020] (2) The degreasing temperature of the annealing furnace should be heated to 90-120 degrees Celsius. If the temperature is lower than this, the degreasing effect will not be achieved. If the temperature is higher than this, it will easily affect the properties of the aluminum alloy. The holding time should be sufficient. If it is less than 10 hours, the volatilization will not be thorough enough, resulting in incomplete degreasing.

[0021] (3) The vacuum pump is turned on during the heat preservation process to extract the generated waste gas, avoid the increase of gas pressure in the furnace, and ensure that the rolling oil can be recovered and reused, thus avoiding the consumption of alkali or acid and the generation of sewage caused by conventional control methods.

[0022] It should be noted that the vacuum pressure, annealing degreasing temperature, and annealing degreasing holding time should all fall within the aforementioned ranges. However, it is best to avoid both the degreasing temperature and holding time being at their upper or lower limits simultaneously. When both are at the lower limit, the surface rolling oil is difficult to evaporate, which is detrimental to the degreasing effect; when both are at the upper limit, significant changes in the properties of the aluminum material are likely to occur. The vacuum pressure should be reduced as much as possible. If it is difficult to reduce it further, the degreasing temperature should be appropriately increased and the holding time extended.

[0023] The aluminum alloy coils produced by the above method can achieve rapid degreasing of the surface of the aluminum alloy coils without cleaning or annealing in a protective atmosphere furnace, and can also achieve the effect of recycling and reuse of the rolling oil on the surface of the aluminum coils.

[0024] This invention utilizes the principle that the evaporation point temperature of rolling oil decreases under vacuum conditions to design a vacuum degreasing annealing process. It effectively combines a vacuum pump to extract the evaporating rolling oil vapors to a recovery pan, where the recovered oil vapors are restored to liquid form at room temperature and then recycled. Because the processing temperature is low, it does not affect the properties of the aluminum alloy coil itself, nor does it affect the properties of the rolling oil.

[0025] Example 1:

[0026] Aluminum alloy coils of 1050 alloy in H19 condition, with specifications of 0.290*1350*C, were cold-rolled and their surface grayscale value A1 was measured. Subsequently, the surface was cleaned with deionization according to conventional processes, and its grayscale value B1 and yield strength C1 were measured.

[0027] Example 2:

[0028] Aluminum alloy coils of 1050 alloy in H19 condition, with specifications of 0.290*1350*C, were cold-rolled and their surface grayscale value A2 was measured. The cold-rolled aluminum alloy coils were then sent to a vacuum-capable box-type annealing furnace. The annealing furnace was evacuated (air pressure inside the annealing furnace was 5pa), and then heated to 95 degrees Celsius and held for 15 hours. During the holding process, the vacuum pump was turned on to draw the waste gas generated inside the furnace to a recovery tray outside the annealing furnace. The recovered liquid portion could be recycled for cold rolling again. After degreasing and annealing, the grayscale value B2 of the coils was measured, and the yield strength C2 was also measured.

[0029] Example 3:

[0030] Aluminum alloy coils in H24 state of 5052 alloy, with specifications of 1.47*1250*C, were cold-rolled and their surface grayscale value A3 was measured. Then, the surface was cleaned with deionization according to conventional processes, and then stabilized and annealed according to the H24 process to obtain aluminum coils in H24 state. The obtained H24 state aluminum coils were measured for their grayscale value B3 and yield strength C3.

[0031] Example 4:

[0032] 5052 alloy H24 temper aluminum alloy coils with specifications of 1.47*1250*C were cold-rolled and their surface grayscale value A4 was measured. The cold-rolled aluminum alloy coils were then sent to a vacuum-capable box-type annealing furnace. The annealing furnace was evacuated (air pressure inside the annealing furnace was 5pa), and then heated to 95 degrees Celsius and held for 20 hours. During the holding process, the vacuum pump was turned on to draw the waste gas generated in the furnace to a recovery tray outside the annealing furnace. The recovered liquid portion can be recycled for cold rolling again. After degreasing and annealing, the coils were then stabilized and annealed according to the H24 process to obtain H24 temper aluminum coils. The obtained H24 temper aluminum coils were measured for their grayscale value B4 and yield strength C4.

[0033] Example 5:

[0034] 5052 alloy H24 temper aluminum alloy coils with specifications of 1.47*1250*C were cold-rolled and their surface grayscale value A5 was measured. The cold-rolled aluminum alloy coils were then sent to a vacuum-capable box-type annealing furnace. The annealing furnace was evacuated (air pressure inside the annealing furnace was 5pa) and heated to 140 degrees Celsius, and held for 20 hours. During the holding process, the vacuum pump was turned on to draw the waste gas generated in the furnace to a recovery tray outside the annealing furnace. The recovered liquid portion can be recycled for cold rolling again. After degreasing and annealing, the coils were then stabilized and annealed according to the H24 process to obtain H24 temper aluminum coils. The obtained H24 temper aluminum coils were measured for their grayscale value B5 and yield strength C5.

[0035] Example 6:

[0036] Aluminum alloy coils of 5052 alloy in H24 condition, with specifications of 1.47*1250*C, were cold-rolled and their surface grayscale value A6 was measured. The cold-rolled aluminum alloy coils were then sent to a vacuum-capable box-type annealing furnace. The annealing furnace was evacuated (air pressure inside the annealing furnace was 5pa), and then heated to 120 degrees Celsius and held for 5 hours. During the holding process, the vacuum pump was turned on to draw the waste gas generated in the furnace to a recovery tray outside the annealing furnace. The recovered liquid portion could be recycled for cold rolling again. After degreasing and annealing, the coils were then stabilized and annealed according to the H24 process to obtain aluminum coils in H24 condition. The obtained H24 condition aluminum coils were measured for their grayscale value B6 and yield strength C6.

[0037] Example 7:

[0038] Aluminum alloy coils of 5052 alloy in H24 condition, with specifications of 1.47*1250*C, were cold-rolled and their surface grayscale value was measured to be A7. The cold-rolled aluminum alloy coils were then sent to a vacuum-capable box-type annealing furnace. The annealing furnace was evacuated (air pressure inside the annealing furnace was 5pa), and then heated to 70 degrees Celsius and held for 25 hours. During the holding process, the vacuum pump was turned on to draw the waste gas generated in the furnace to a recovery tray outside the annealing furnace. The recovered liquid portion could be recycled for cold rolling again. After degreasing and annealing, the coils were then stabilized and annealed according to the H24 process to obtain aluminum coils in H24 condition. The obtained H24 condition aluminum coils were tested for their grayscale value B7 and yield strength C7.

[0039] Example 8:

[0040] 5052 alloy H24 temper aluminum alloy coils with specifications of 1.47*1250*C were cold-rolled and their surface grayscale value A8 was measured. The cold-rolled aluminum alloy coils were then sent to a vacuum-capable box-type annealing furnace. The annealing furnace was evacuated (air pressure inside the annealing furnace was 1000pa), and then heated to 95 degrees Celsius and held for 20 hours. During the holding process, the vacuum pump was turned on to draw the waste gas generated in the furnace to a recovery tray outside the annealing furnace. The recovered liquid portion could be recycled for cold rolling again. After degreasing and annealing, the coils were then stabilized and annealed according to the H24 process to obtain H24 temper aluminum coils. The obtained H24 temper aluminum coils were measured for their grayscale value B8 and yield strength C8.

[0041] The changes in grayscale values ​​and yield strength obtained under different production conditions are shown in the table below.

[0042]

[0043] In Examples 1 and 2, by comparing with conventional control methods, it can be seen that this embodiment can obtain aluminum coils with high cleanliness without cleaning, that is, without generating wastewater.

[0044] In Examples 3 through 8, different degreasing control pressures, temperatures, and times resulted in different grayscale values ​​or material properties. When the temperature exceeded the range, significant changes in material properties were easily caused; when the degreasing control pressure exceeded the range or the degreasing temperature or holding time was insufficient, surface cleanliness was difficult to improve.

[0045] If this invention discloses or relates to components or structural parts that are fixedly connected to each other, then, unless otherwise stated, a fixed connection can be understood as: a fixed connection that can be detached (e.g., using bolts or screws), or a fixed connection that cannot be detached (e.g., riveting, welding). Of course, a fixed connection can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0046] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0047] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A green and recyclable preparation method for rapid degreasing and annealing of aluminum alloy coils, characterized in that: The cold-rolled aluminum alloy coil is fed into an annealing furnace. After the annealing furnace is evacuated, it is heated to 90-120 degrees Celsius and held for more than 10 hours. The annealing furnace performs degreasing annealing on the aluminum alloy coil. After the annealing furnace is evacuated, the air pressure inside the annealing furnace is 0-10 Pa to ensure that the pressure is in a vacuum state of 0-10 Pa during the degreasing annealing process.

2. The green and recyclable preparation method for rapid degreasing and annealing of aluminum alloy coils according to claim 1, characterized in that: The annealing furnace is connected to a vacuum pump; during the heat preservation process, the vacuum pump is turned on to draw the waste gas generated in the annealing furnace to the recovery tray outside the annealing furnace, and the recovered liquid can be recycled again for cold rolling.

3. The green and recyclable preparation method for rapid degreasing and annealing of aluminum alloy coils according to claim 1, characterized in that: The annealing furnace is a box-type or bell-type annealing furnace that can be vacuumed.

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