High yield, high fatigue pressure die casting aluminum alloy material and preparation method thereof

Abstract

The application discloses a kind of high yield, high fatigue die-casting aluminum alloy material and preparation method thereof;The application is by designing the range of Mg+Zn total amount and the range of Cu / Mg and simultaneously controlling the design range of X element, while maintaining high alloy strength, avoiding the existence of too much coarse second phase in organization to deteriorate alloy performance, reducing the tendency of alloy hot cracking, adding trace elements, through the synergistic effect between elements, breaking the limitation of single element, doubling the strengthening effect of microalloying, realizing the substantial improvement of material comprehensive performance.Aluminum alloy component after high-pressure casting forming does not need to be heat treated, high room temperature yield strength is obtained, tensile strength ≥330MPa, yield strength ≥220MPa, elongation after break ≥3.0%, fatigue strength ≥120Mpa, which can meet the high requirements of current integrated multi-in-one electric drive on materials under severe and complex working conditions, and solves the failure phenomena such as stress exceeding standard, leakage, deformation and fracture of electric drive products under special working conditions.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, specifically to a high-yield, high-fatigue die-cast aluminum alloy material and its preparation method. Background Technology

[0002] High yield and high fatigue aluminum alloy materials are widely in demand in the fields of electric vehicle three-electric system housings and other areas. With the rapid development of electric vehicle technology, electric drive systems are constantly developing towards higher speed, multi-integration, and higher power density.

[0003] The shortcomings of existing technology: Currently, automotive electric drive systems (especially structural components such as housings, end caps, and rotors) widely use aluminum-silicon-copper cast aluminum alloys such as ADC12 and AlSi9Cu3. Their typical properties are: yield strength: 140-180 MPa; tensile strength: 230-280 MPa; elongation: 1-2%; Brinell hardness: 80-100 HB. Under the harsh and complex conditions brought about by integration—including high motor speeds, random vibrations transmitted from the road surface, and torque fluctuations generated by the internal rotor rotation—deformation, cracking, and fatigue failure are highly likely to occur. Summary of the Invention

[0004] The purpose of this invention is to provide a high-yield, high-fatigue die-cast aluminum alloy material and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-yield, high-fatigue die-cast aluminum alloy material, wherein the aluminum alloy material comprises: Si 8.5%-10.0%, Cu 1.8%-3.0%, Zn 0.5-1.5%, Mn 0.4-0.8%, Mg 0.6%-1.5%, Fe≤0.25%, Sr 0.010%-0.045%, X 0.1%-0.25%, with the balance being Al, and the total content of other impurities not exceeding 0.25%; the aluminum alloy material further comprises any two or more elements selected from V, Mo, Sc, Zr and Ni.

[0006] Preferably, the mass relationship between Mg and Zn is as follows: 2.0 wt.% ≤ Mg + Zn ≤ 3.0 wt.%.

[0007] Preferably, the mass relationship between Cu and Mg is as follows: 2 < Cu / Mg < 3.

[0008] Preferably, the content of a single element in element X is less than or equal to 0.20%, and element X includes element V or element Sc.

[0009] Preferably, when X1 is added as an element of V, the sum of X1 and the remaining elements X n The mass ratio is 1 / 7 to 1.5; when X1 is added as an element of Sc, the sum of Sc and the remaining elements is X. n The mass ratio is 1 / 4 to 3.

[0010] This invention also provides a method for preparing a high-yield, high-fatigue die-cast aluminum alloy material, the preparation method specifically including the following steps: S1. Prepare aluminum alloy raw materials and obtain alloy melt; S2. Add refining agent to the alloy melt to remove gas and slag; S3. The alloy melt is shaped into aluminum alloy components using equipment.

[0011] Preferably, step S1 specifically includes: a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy to the melting furnace in sequence, and add any two or more of Al-V, Al-Ni, Al-Mo, Al-Sc, and Al-Zr alloys as needed. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 150-250℃, the melting temperature is set to 730-780℃, and the stirring time is set to 10-15min.

[0012] Preferably, in step S2: a protective gas is introduced into the alloy melt, the refining time is set to 20-30 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 0.15-6 L / min; the degassing rotor speed is set to 400-550 r / min, the pressure is set to 0.2-0.4 MPa, and the flow rate is set to 16-20 L / min.

[0013] Preferably, the aluminum alloy material has a yield strength greater than 220 MPa and an elongation greater than 3% at room temperature.

[0014] Preferably, the aluminum alloy material is used in the electric drive system of new energy vehicles.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention relates to a high-yield, high-fatigue die-cast aluminum alloy material and its preparation method. By designing the total Mg+Zn content range and the Cu / Mg ratio range, while simultaneously controlling the design range of X element, it maintains high alloy strength while avoiding excessive coarse second phases in the microstructure that would degrade alloy performance and reduce the alloy's tendency for hot cracking. The addition of trace elements, through synergistic effects, overcomes the limitations of single elements, significantly enhancing the strengthening effect of micro-alloying and achieving a substantial improvement in the material's overall performance. After high-pressure die casting, the aluminum alloy component requires no heat treatment, achieving high room-temperature yield strength, tensile strength ≥330MPa, yield strength ≥220MPa, elongation after fracture ≥3.0%, and fatigue strength ≥120MPa. This material can meet the high requirements of current integrated multi-functional electric drives under harsh and complex operating conditions, solving failure phenomena such as excessive stress, leakage, deformation, and fracture in electric drive products under special operating conditions. Attached Figure Description

[0016] Figure 1 This is a representative microstructure of the aluminum alloy after high-pressure casting in Example 1 of the present invention. Figure 2 This is a representative microstructure diagram of the aluminum alloy after tensile fracture following high-pressure casting in Example 1 of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, 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. Therefore, they should not be construed as limitations on this invention.

[0019] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integrated connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0021] Example 1 Please see Figure 1-2 As shown, this invention provides a high-yield, high-fatigue die-cast aluminum alloy material technical solution: the aluminum alloy material comprises: Si 9.95%, Cu 1.83%, Zn 1.43%, Mn 0.52%, Mg 0.65%, Fe 0.10%, Sr 0.025%, V 0.10%, 0.10% Mo, with the balance being Al, and the total content of other impurities not exceeding 0.25%; the mass relationship between Mg and Zn is Mg+Zn = 2.08 wt.%, and the mass relationship between Cu and Mg is Cu / Mg = 2.82. The aluminum alloy material can also be applied to the electric drive system of new energy vehicles.

[0022] This invention also provides a method for preparing high-yield, high-fatigue die-cast aluminum alloy materials: S1. Prepare aluminum alloy raw materials and obtain alloy melt; a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy, Al-V and Al-Mo alloy as needed to the melting furnace in sequence. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 250℃, the melting temperature is set to 780℃, and the stirring time is set to 10min. S2. Add a refining agent to the alloy melt to degas and remove slag; introduce a protective gas into the alloy melt, set the refining time to 20 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 3 L / min. S3. The alloy melt is formed into aluminum alloy components using high-pressure casting equipment.

[0023] The main mechanical properties of the standard specimens prepared above are as follows: tensile strength 342 MPa, yield strength 232 MPa, elongation after fracture 3.26%, and fatigue strength 128 MPa.

[0024] Example 2 This invention provides a high-yield, high-fatigue die-cast aluminum alloy material technical solution: the aluminum alloy material comprises: Si 9.70%, Cu 2.53%, Zn 1.23%, Mn 0.48%, Mg 1.08%, Fe 0.09%, Sr 0.028%, V 0.03%, 0.10% Mo, 0.05% Sc, with the balance being Al, and the total content of other impurities not exceeding 0.25%. The mass relationship between Mg and Zn is Mg + Zn = 2.31 wt.%, and the mass relationship between Cu and Mg is Cu / Mg = 2.34. The aluminum alloy material can also be applied to the electric drive system of new energy vehicles.

[0025] This invention also provides a method for preparing high-yield, high-fatigue die-cast aluminum alloy materials: S1. Prepare aluminum alloy raw materials and obtain alloy melt; a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy, Al-V, Al-Mo, and Al-Sc alloy as needed to the melting furnace in sequence. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 250℃, the melting temperature is set to 780℃, and the stirring time is set to 10min. S2. Add a refining agent to the alloy melt to degas and remove slag; introduce a protective gas into the alloy melt, set the refining time to 20 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 3 L / min. S3. The alloy melt is formed into aluminum alloy components using high-pressure casting equipment.

[0026] The main mechanical properties of the standard specimens prepared above are as follows: tensile strength 362 MPa, yield strength 228 MPa, elongation after fracture 3.35%, and fatigue strength 124 MPa.

[0027] Example 3 This invention provides a high-yield, high-fatigue die-cast aluminum alloy material technical solution: the aluminum alloy material comprises: Si 9.67%, Cu 2.79%, Zn 1.31%, Mn 0.50%, Mg 1.11%, Fe 0.10%, Sr 0.023%, V 0.03%, 0.10% Zr, 0.10% Sc, with the balance being Al, and the total content of other impurities not exceeding 0.25%. The mass relationship between Mg and Zn is Mg + Zn = 2.42 wt.%, and the mass relationship between Cu and Mg is Cu / Mg = 2.51. This aluminum alloy material can also be applied to electric drive systems for new energy vehicles.

[0028] This invention also provides a method for preparing high-yield, high-fatigue die-cast aluminum alloy materials: S1. Prepare aluminum alloy raw materials and obtain alloy melt; a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy, Al-V, Al-Zr, and Al-Sc alloy to the melting furnace in sequence. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 250℃, the melting temperature is set to 780℃, and the stirring time is set to 10min. S2. Add a refining agent to the alloy melt to degas and remove slag; introduce a protective gas into the alloy melt, set the refining time to 20 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 3 L / min. S3. The alloy melt is formed into aluminum alloy components using high-pressure casting equipment.

[0029] The main mechanical properties of the standard specimens prepared above are as follows: tensile strength 337MPa, yield strength 235MPa, elongation after fracture 3.18%, and fatigue strength 122MPa.

[0030] Example 4 This invention provides a high-yield, high-fatigue die-cast aluminum alloy material technical solution: the aluminum alloy material comprises: Si 9.96%, Cu 2.77%, Zn 1.24%, Mn 0.47%, Mg 1.12%, Fe 0.11%, Sr 0.021%, V 0.10%, Ni 0.10%, with the balance being Al, and the total content of other impurities not exceeding 0.25%. The mass ratio of Mg to Zn is Mg + Zn = 2.36 wt.%, and the mass ratio of Cu to Mg is Cu / Mg = 2.47. This aluminum alloy material can also be applied to electric drive systems for new energy vehicles.

[0031] This invention also provides a method for preparing high-yield, high-fatigue die-cast aluminum alloy materials: S1. Prepare aluminum alloy raw materials and obtain alloy melt; a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy, Al-V and Al-Ni alloy as needed to the melting furnace in sequence. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 250℃, the melting temperature is set to 780℃, and the stirring time is set to 10min. S2. Add a refining agent to the alloy melt to degas and remove slag; introduce a protective gas into the alloy melt, set the refining time to 20 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 3 L / min. S3. The alloy melt is formed into aluminum alloy components using high-pressure casting equipment.

[0032] The main mechanical properties of the standard specimens prepared above are as follows: tensile strength 351 MPa, yield strength 230 MPa, elongation after fracture 3.07%, and fatigue strength 125 MPa.

[0033] Example 5 This invention provides a high-yield, high-fatigue die-cast aluminum alloy material technical solution: the aluminum alloy material comprises: Si 8.99%, Cu 2.12%, Zn 1.21%, Mn 0.65%, Mg 1.05%, Fe 0.17%, Sr 0.031%, 0.05% Ni, 0.05% Mo, 0.10% Sc, with the balance being Al, and the total content of other impurities not exceeding 0.25%. The mass relationship between Mg and Zn is Mg + Zn = 2.26 wt.%, and the mass relationship between Cu and Mg is Cu / Mg = 2.02. The aluminum alloy material can also be applied to the electric drive system of new energy vehicles.

[0034] This invention also provides a method for preparing high-yield, high-fatigue die-cast aluminum alloy materials: S1. Prepare aluminum alloy raw materials and obtain alloy melt; a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy, Al-Ni, Al-Mo, and Al-Sc alloy to the melting furnace in sequence. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 250℃, the melting temperature is set to 780℃, and the stirring time is set to 10min. S2. Add a refining agent to the alloy melt to degas and remove slag; introduce a protective gas into the alloy melt, set the refining time to 20 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 3 L / min. S3. The alloy melt is formed into aluminum alloy components using high-pressure casting equipment.

[0035] The main mechanical properties of the standard specimens prepared above are as follows: tensile strength 358 MPa, yield strength 224 MPa, elongation after fracture 3.28%, and fatigue strength 121 MPa.

[0036] Example 6 This invention provides a high-yield, high-fatigue die-cast aluminum alloy material technical solution: the aluminum alloy material comprises: Si 8.91%, Cu 2.06%, Zn 1.98%, Mn 0.69%, Mg 0.73%, Fe 0.13%, Sr 0.030%, 0.05% Ni, 0.05% Mo, 0.03% Sc, 0.10% Zr, with the balance being Al, and the total content of other impurities not exceeding 0.25%. The mass ratio of Mg to Zn is Mg + Zn = 2.71 wt.%, and the mass ratio of Cu to Mg is Cu / Mg = 2.82. This aluminum alloy material can also be applied to electric drive systems for new energy vehicles.

[0037] This invention also provides a method for preparing high-yield, high-fatigue die-cast aluminum alloy materials: S1. Prepare aluminum alloy raw materials and obtain alloy melt; a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy, Al-Ni, Al-Mo, Al-Sc, and Al-Zr alloy to the melting furnace in sequence. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 250℃, the melting temperature is set to 780℃, and the stirring time is set to 10min. S2. Add a refining agent to the alloy melt to degas and remove slag; introduce a protective gas into the alloy melt, set the refining time to 20 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 3 L / min. S3. The alloy melt is formed into aluminum alloy components using high-pressure casting equipment.

[0038] The main mechanical properties of the standard specimens prepared above are as follows: tensile strength 345MPa, yield strength 229MPa, elongation after fracture 3.64%, and fatigue strength 125MPa.

[0039] Comparative Example Another aluminum alloy material technical solution is provided: the aluminum alloy material is an Al-Si-Cu series aluminum alloy.

[0040] The main mechanical properties of the standard specimens prepared above are as follows: tensile strength 247MPa, yield strength 127MPa, elongation after fracture 1.94%, and fatigue strength 90MPa.

[0041] In summary, through Examples 1-6 and the comparative examples, it was found that by designing the total Mg+Zn range, the total Si+Cu+Mn+Mg+Zn range, and the Cu / Mg range, and utilizing the solid solution strengthening, second-phase strengthening, and age-hardening effects of conventional strengthening elements, aluminum alloy components can achieve considerable strength. Simultaneously, by controlling the design range of element X, while maintaining high alloy strength, the effects of transition elements such as dispersion strengthening, increased undercooling, and heterogeneous nucleation are utilized to refine the grains and microstructure, reduce the alloy's hot cracking tendency, avoid excessive coarse second phases in the microstructure which would degrade alloy properties, and significantly improve the alloy's fatigue strength. After adding trace amounts of transition elements, the alloy microstructure is uniform and fine, and no coarse second phases were found in the microstructure. Conventional Al-Si-Cu alloys used in electric drives have poor overall strength and toughness, and low fatigue strength. The newly developed high-yield and high-fatigue die-cast aluminum alloy has excellent mechanical properties, with tensile strength greater than 330 MPa, yield strength greater than 220 MPa, elongation greater than 3%, and fatigue strength greater than 120 MPa. Its comprehensive performance is significantly better than that of traditional Al-Si-Cu alloys.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-yield, high-fatigue die-cast aluminum alloy material, characterized in that: The aluminum alloy material comprises: Si 8.5%-10.0%, Cu 1.8%-3.0%, Zn 0.5%-1.5%, Mn 0.4%-0.8%, Mg 0.6%-1.5%, Fe≤0.25%, Sr 0.010%-0.045%, X 0.1%-0.25%, with the balance being Al, and the total content of other impurities not exceeding 0.25%; the aluminum alloy material also includes any two or more elements selected from V, Mo, Sc, Zr and Ni.

2. The high yield strength and high fatigue strength die-cast aluminum alloy material according to claim 1, characterized in that: The mass relationship between Mg and Zn is as follows: 2.0 wt.% ≤ Mg + Zn ≤ 3.0 wt.%.

3. The high yield strength and high fatigue strength die-cast aluminum alloy material according to claim 1, characterized in that: The mass relationship between Cu and Mg is as follows: 2 < Cu / Mg < 3.

4. The high-yield, high-fatigue die-cast aluminum alloy material according to claim 1, characterized in that: The content of a single element in element X is less than or equal to 0.20%, and element X includes element V or element Sc.

5. The high-yield, high-fatigue die-cast aluminum alloy material according to claim 1, characterized in that: When X1 is added as an element of V, the sum of X1 and the remaining elements is X. n The mass ratio is 1 / 7 to 1.5; when X1 is added as an element of Sc, the sum of Sc and the remaining elements is X n The mass ratio is 1 / 4 to 3.

6. A method for preparing a high-yield, high-fatigue die-cast aluminum alloy material according to any one of claims 1-5, characterized in that: The preparation method specifically includes the following steps: S1. Prepare aluminum alloy raw materials and obtain alloy melt; S2. Add refining agent to the alloy melt to remove gas and slag; S3. The alloy melt is shaped into aluminum alloy components using equipment.

7. The method for preparing a high-yield, high-fatigue die-cast aluminum alloy material according to claim 6, characterized in that: Step S1 specifically includes: a1. Prepare raw materials according to the composition range of aluminum alloy materials, and weigh the raw materials according to the corresponding weight percentage; a2. Add the A00 aluminum ingot to the smelting furnace and melt it completely; a3. Add metallic silicon, recycled copper, Zn ingot, Al-Mn alloy to the melting furnace in sequence, and add any two or more of Al-V, Al-Ni, Al-Mo, Al-Sc, and Al-Zr alloys as needed. After complete melting, add Mg ingot and Al-Sr master alloy. a4. Drying and preheating, batch melting and stirring are carried out to obtain alloy melt, wherein the drying and preheating temperature is set to 150-250℃, the melting temperature is set to 730-780℃, and the stirring time is set to 10-15min.

8. The method for preparing a high-yield, high-fatigue die-cast aluminum alloy material according to claim 6, characterized in that: Step S2: A protective gas is introduced into the alloy melt, the refining time is set to 20-30 min, the protective gas is nitrogen or argon, and the protective gas flow rate is 0.15-6 L / min; the degassing rotor speed is set to 400-550 r / min, the pressure is set to 0.2-0.4 MPa, and the flow rate is set to 16-20 L / min.

9. The method for preparing a high-yield, high-fatigue die-cast aluminum alloy material according to claim 6, characterized in that: The aluminum alloy material has a yield strength greater than 220 MPa and an elongation greater than 3% at room temperature.

10. The method for preparing a high-yield, high-fatigue die-cast aluminum alloy material according to claim 6, characterized in that: The aluminum alloy material is used in the electric drive system of new energy vehicles.

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