Preparation method of aluminum alloy for molecular pump rotor

Abstract

The invention provides a preparation method of an aluminum alloy for a molecular pump rotor, which comprises the following steps: sequentially carrying out annealing treatment, forging treatment, solution treatment and aging treatment on a blank to obtain the aluminum alloy, the blank comprises, by mass, 0.10%-0.20% of Si, 0.8%-1.2% of Fe, 2.0%-2.5% of Cu, smaller than or equal to 0.05% of Mn, 1.4%-1.8% of Mg, smaller than or equal to 0.05% of Cr, smaller than or equal to 0.05% of Zn, smaller than or equal to 0.05%-0.10% of Ti and the balance aluminum. The aluminum alloy prepared by the preparation method has excellent heat resistance, and can maintain good mechanical properties at a high temperature of 120 DEG C or above.

Description

Technical Field

[0001] The invention belongs to the field of metal material preparation, and relates to a method for preparing an aluminum alloy for a molecular pump rotor. Background Art

[0002] The molecular pump uses a high-speed rotating rotor to transfer momentum to gas molecules. In the molecular flow area, the gas molecules collide with the surface of the high-speed rotating blades, and the momentum is transferred to the gas molecules, so that some gas molecules produce directional flow in the direction of motion of the rigid surface and are discharged from the pump, thereby achieving the purpose of pumping. The core components of the molecular pump are rotating blades and fixed blades. When the molecular pump is working at a uniform speed, the rotor blades are subjected to the centrifugal force (the resistance is very small and can be ignored under vacuum), that is, the pulling force in the direction away from the axis; when accelerating and decelerating, the blades are also subjected to the force in the direction of the rotation tangent, which is equivalent to the force that bends the blades. At the same time, the molecular pump needs to be preheated when working, so it has high requirements for the high-temperature mechanical properties of the material. The existing material blades can operate normally during normal temperature use, but when facing a high-temperature environment, the mechanical properties of the blades are significantly reduced, and the violent collision with the gas molecules during rotation and pumping causes fragmentation.

[0003] CN 110005639A discloses a composite turbomolecular pump rotor and a preparation method thereof, wherein the turbomolecular pump rotor comprises at least one set of first rotor ring, second rotor ring, third rotor ring and blades which are stacked in sequence; wherein the first rotor ring and the third rotor ring are aluminum or aluminum alloy rotor rings, the second rotor ring is titanium or titanium alloy interval rotor ring, and the blades are titanium or titanium alloy blades. The molecular pump rotor needs to use titanium or titanium alloy to enhance the strength of the rotor, and is not an improvement on the aluminum alloy itself used for the molecular pump rotor.

[0004] CN 112458442 A discloses a preparation method for improving the bonding strength between titanium aluminum alloy and oxide coating, comprising the following steps: step 1, preparing a TiO2 buffer layer on the surface of the titanium aluminum alloy by a sol-gel method; step 2, using high-energy argon ions to perform ion bombardment treatment on the surface of the TiO2 buffer layer; step 3, dipping the coating slurry on the surface of the TiO2 buffer layer treated by ion bombardment, drying and sintering, and completing the bonding between the titanium aluminum alloy and the oxide coating. The titanium aluminum alloy is improved in heat resistance by a composite oxide coating, which requires the use of ion bombardment and other processes, and the preparation method is complex and costly. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a method for preparing an aluminum alloy for a molecular pump rotor. The aluminum alloy prepared by the preparation method has excellent heat resistance and can maintain good mechanical properties even at high temperatures above 120°C.

[0006] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing an aluminum alloy for a molecular pump rotor. The preparation method comprises:

[0008] The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence to obtain an aluminum alloy;

[0009] Calculated by mass fraction, the composition of the billet includes Si: 0.10-0.20%, Fe: 0.8-1.2%, Cu: 2.0-2.5%, Mn: ≤0.05%, Mg: 1.4-1.8%, Cr: ≤0.05%, Zn: ≤0.05%, Ti: ≤0.05-0.10%, and the balance is aluminum.

[0010] As a preferred technical solution of the present invention, the annealing temperature is 450-500° C. and the time is 12-24 hours.

[0011] As a preferred technical solution of the present invention, the blank is subjected to heat preservation treatment before forging.

[0012] As a preferred technical solution of the present invention, the temperature of the heat preservation treatment is 350-450° C. and the time is 6-12 hours.

[0013] As a preferred technical solution of the present invention, the forging process includes sequentially performing drawing and upsetting.

[0014] As a preferred technical solution of the present invention, the ratio of drawing to upsetting forging is 2-3.

[0015] As a preferred technical solution of the present invention, the stretching and upsetting are repeated 2 to 3 times.

[0016] As a preferred technical solution of the present invention, the temperature of the solution treatment is 510-540° C. and the time is 6-10 hours.

[0017] As a preferred technical solution of the present invention, the temperature of the aging treatment is 180-220° C. and the time is 12-20 hours.

[0018] As a preferred technical solution of the present invention, the method for preparing the aluminum alloy for the molecular pump rotor comprises:

[0019] The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence;

[0020] The annealing temperature is 450-500°C and the time is 12-24h;

[0021] Before forging, the blank is subjected to heat preservation treatment at a temperature of 350 to 450° C. for a time of 6 to 12 hours;

[0022] The forging process includes sequential drawing and upsetting, the drawing and upsetting forging ratio is 2 to 3, and the drawing and upsetting are repeated 2 to 3 times;

[0023] The temperature of solution treatment is 510-540°C and the time is 6-10h;

[0024] The temperature of aging treatment is 180-220°C and the time is 12-20h.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] The invention provides a method for preparing an aluminum alloy for a molecular pump rotor. The aluminum alloy prepared by the preparation method has excellent heat resistance and can maintain good mechanical properties even at a high temperature above 120°C. DETAILED DESCRIPTION

[0027] The technical solution of the present application is further described below through specific implementation methods.

[0028] A specific embodiment of the present invention provides a method for preparing an aluminum alloy for a molecular pump rotor. The preparation method comprises:

[0029] The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence to obtain an aluminum alloy;

[0030] Calculated by mass fraction, the composition of the billet includes Si: 0.10-0.20%, Fe: 0.8-1.2%, Cu: 2.0-2.5%, Mn: ≤0.05%, Mg: 1.4-1.8%, Cr: ≤0.05%, Zn: ≤0.05%, Ti: ≤0.05-0.10%, and the balance is aluminum.

[0031] Among them, the mass fraction of silicon can be 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19% or 0.20%, etc., the mass fraction of iron can be 0.8%, 0.9%, 1.0%, 1.1% or 1.2%, etc., the mass fraction of copper can be 2.0%, 2.1%, 2.2%, 2.3%, 2.4% or 2.5%, etc., the mass fraction of manganese can be 0.01%, 0.02%, 0.03%, 0.04% or 0.05%, etc., The mass fraction of magnesium can be 1.4%, 1.5%, 1.6%, 1.7% or 1.8%, etc., the mass fraction of chromium can be 0.01%, 0.02%, 0.03%, 0.04% or 0.05%, etc., the mass fraction of zinc can be 0.01%, 0.02%, 0.03%, 0.04% or 0.05%, etc., the mass fraction of titanium can be 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.10%, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical ranges are equally applicable.

[0032] In a specific embodiment of the present invention, the annealing temperature is 450-500°C and the time is 12-24h. The temperature may be 450°C, 460°C, 470°C, 480°C, 490°C or 500°C, and the time may be 12h, 14h, 16h, 18h, 20h, 22h or 24h, but is not limited to the listed values. Other values ​​not listed within the above ranges are also applicable.

[0033] In a specific embodiment of the present invention, the blank is subjected to a heat preservation treatment before forging.

[0034] In a specific embodiment of the present invention, the temperature of the heat preservation treatment is 350-450°C, and the time is 6-12h. The temperature can be 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C or 450°C, and the time can be 6h, 7h, 8h, 9h, 10h, 11h or 12h, but it is not limited to the listed values, and other values ​​not listed in the above ranges are also applicable.

[0035] In one embodiment of the present invention, the forging process includes sequentially performing drawing and upsetting.

[0036] In a specific embodiment of the present invention, the ratio of drawing to upsetting forging is 2-3.

[0037] In one specific embodiment of the present invention, the stretching and upsetting are repeated 2 to 3 times.

[0038] In a specific embodiment of the present invention, the temperature of the solution treatment is 510-540°C, and the time is 6-10 hours. The temperature may be 510°C, 515°C, 520°C, 525°C, 530°C, 535°C or 540°C, and the time may be 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, but is not limited to the listed values, and other values ​​not listed within the above ranges are also applicable.

[0039] In a specific embodiment of the present invention, the temperature of the aging treatment is 180-220°C, and the time is 12-20h. The time can be 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C or 220°C, and the time can be 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h or 20h, but is not limited to the listed values, and other values ​​not listed within the above numerical ranges are also applicable.

[0040] In a specific embodiment of the present invention, the billet is cooled after the aging treatment to obtain the aluminum alloy, and the cooling method is preferably air cooling.

[0041] In the present invention, by selecting the elements added to the aluminum alloy, combining the heat treatment and forging process, and further controlling the heat treatment and forging process conditions, the high temperature resistance of the aluminum alloy is improved, and the aluminum alloy is not only suitable for the manufacture of molecular pump rotors, but also can adapt to the heating high-temperature working environment, and the mechanical properties fluctuate little under high temperature conditions, thereby avoiding the fragmentation phenomenon caused by the violent collision between the molecular pump rotor and the gas molecules during rotation and pumping.

[0042] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0043] Example 1

[0044] This embodiment provides a method for preparing an aluminum alloy for a molecular pump rotor, the preparation method comprising:

[0045] The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence;

[0046] The annealing temperature is 450°C and the time is 24h;

[0047] The blank is subjected to heat preservation treatment before forging, the temperature of the heat preservation treatment is 350° C., and the time is 12 hours;

[0048] The forging process includes sequential drawing and upsetting, the drawing and upsetting forging ratio is 2, and the drawing and upsetting are repeated 3 times;

[0049] The temperature of solution treatment is 510℃ and the time is 10h;

[0050] The aging treatment temperature is 220°C and the time is 20h;

[0051] After aging treatment, air cooling is performed to obtain an aluminum alloy for a molecular pump rotor.

[0052] Example 2

[0053] This embodiment provides a method for preparing an aluminum alloy for a molecular pump rotor, the preparation method comprising:

[0054] The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence;

[0055] The annealing temperature is 500°C and the time is 12h;

[0056] The blank is subjected to heat preservation treatment before forging, the temperature of the heat preservation treatment is 450° C., and the time is 6 hours;

[0057] The forging process includes sequential drawing and upsetting, the drawing and upsetting forging ratio is 3, and the drawing and upsetting are repeated 2 times;

[0058] The temperature of solution treatment is 540℃ and the time is 6h;

[0059] The aging treatment temperature is 220°C and the time is 12h;

[0060] After aging treatment, air cooling is performed to obtain an aluminum alloy for a molecular pump rotor.

[0061] Example 3

[0062] This embodiment provides a method for preparing an aluminum alloy for a molecular pump rotor, the preparation method comprising:

[0063] The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence;

[0064] The annealing temperature is 475°C and the time is 18h;

[0065] The blank is subjected to heat preservation treatment before forging, the temperature of the heat preservation treatment is 400° C., and the time is 9 hours;

[0066] The forging process includes sequential drawing and upsetting, the drawing and upsetting forging ratio is 2, and the drawing and upsetting are repeated 3 times;

[0067] The temperature of solution treatment is 520℃ and the time is 8h;

[0068] The aging treatment temperature is 200°C and the time is 16h;

[0069] After aging treatment, air cooling is performed to obtain an aluminum alloy for a molecular pump rotor.

[0070] Example 4

[0071] This embodiment provides a method for preparing an aluminum alloy for a molecular pump rotor, the preparation method comprising:

[0072] The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence;

[0073] The annealing temperature is 460°C and the time is 20h;

[0074] Before forging, the blank is subjected to a heat preservation treatment at a temperature of 380° C. for 10 hours;

[0075] The forging process includes sequential drawing and upsetting, the drawing and upsetting forging ratio is 3, and the drawing and upsetting are repeated 3 times;

[0076] The solution treatment temperature was 530 °C and the time was 7 h;

[0077] The aging treatment temperature is 210°C and the time is 15h;

[0078] After aging treatment, air cooling is performed to obtain an aluminum alloy for a molecular pump rotor.

[0079] Example 5

[0080] Except for the composition of the blank, other conditions of this embodiment are the same as those of embodiment 4.

[0081] Comparative Example 1

[0082] Except that the annealing treatment is not performed, the other conditions of this comparative example are the same as those of Example 4.

[0083] Comparative Example 2

[0084] Except that the forging process is not performed, the other conditions of this comparative example are the same as those of Example 4.

[0085] Comparative Example 3

[0086] In this comparative example, the conditions are the same as those of Example 4 except that the forging treatment is directly performed after the billet temperature reaches 380°C, that is, no heat preservation treatment is performed.

[0087] Comparative Example 4

[0088] Except for the forging ratio being 5, the other conditions of this comparative example are the same as those of Example 4.

[0089] Comparative Example 5

[0090] Except that the solution treatment is not performed, the other conditions of this comparative example are the same as those of Example 4.

[0091] Comparative Example 6

[0092] Except that the aging treatment is not performed, the other conditions of this comparative example are the same as those of Example 4.

[0093] The elemental composition (mass fraction, unit %) of the blanks in Examples 1-5 is shown in Table 1.

[0094] Table 1

[0095]

[0096] The aluminum alloys provided in Examples 1-5 and Comparative Examples 1-6 were subjected to impact tests. The impact tests adopted GB / T229-2007, and the notch type was a V-notch (depth 2 mm). The tests were performed at 25°C and 125°C, respectively, and the energy absorbed by the completely broken sample at 125°C was divided by the energy absorbed by the completely broken sample at 25°C as the test result. The results are shown in Table 2.

[0097] Table 2

[0098]

[0099]

[0100] It can be seen from the test results in Table 2 that the mechanical properties of the aluminum alloy material prepared by the preparation method of the aluminum alloy for the molecular pump rotor provided in Examples 1-5 of the present invention at a high temperature of 125°C are only reduced by no more than 7% compared with the mechanical properties at a normal temperature of 25°C, and the production requirements of the molecular pump rotor can be met under high temperature conditions. Comparative Examples 1-6 do not perform certain heat treatment steps or adjust the heat treatment conditions, resulting in a significant decrease in the mechanical properties of the prepared aluminum alloy at a high temperature of 125°C compared with the mechanical properties at a normal temperature of 25°C, making it difficult to meet the production requirements of the molecular pump rotor.

[0101] The applicant declares that the present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an aluminum alloy for a molecular pump rotor, characterized in that: The preparation method comprises: The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence to obtain the aluminum alloy; Calculated by mass fraction, the composition of the billet includes Si: 0.10-0.20%, Fe: 0.8-1.2%, Cu: 2.0-2.5%, Mn: ≤0.05%, Mg: 1.4-1.8%, Cr: ≤0.05%, Zn: ≤0.05%, Ti: ≤0.05-0.10%, and the balance is aluminum.

2. The preparation method according to claim 1, characterized in that: The annealing treatment is carried out at a temperature of 450 to 500° C. and for a time of 12 to 24 hours.

3. The preparation method according to claim 1, characterized in that: The blank is subjected to heat preservation treatment before forging.

4. The preparation method according to claim 3, characterized in that: The temperature of the heat preservation treatment is 350-450° C., and the time is 6-12 hours.

5. The preparation method according to claim 1, characterized in that: The forging process includes sequential drawing and upsetting.

6. The preparation method according to claim 5, characterized in that: The ratio of drawing to upsetting forging is 2 to 3.

7. The preparation method according to claim 5, characterized in that: The stretching and upsetting are repeated 2 to 3 times.

8. The preparation method according to claim 1, characterized in that: The temperature of the solution treatment is 510-540° C. and the time is 6-10 hours.

9. The preparation method according to claim 1, characterized in that: The temperature of the aging treatment is 180-220° C., and the time is 12-20 hours.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The preparation method comprises: The blank is subjected to annealing treatment, forging treatment, solution treatment and aging treatment in sequence; The annealing temperature is 450-500°C and the time is 12-24h; Before forging, the blank is subjected to heat preservation treatment at a temperature of 350 to 450° C. for a time of 6 to 12 hours; The forging process includes sequential drawing and upsetting, the drawing and upsetting forging ratio is 2 to 3, and the drawing and upsetting are repeated 2 to 3 times; The temperature of solution treatment is 510-540°C and the time is 6-10h; The temperature of aging treatment is 180-220°C and the time is 12-20h.

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