Heat treatment method for eliminating room-temperature parking effect of 6000-series aluminum alloy

Abstract

The invention discloses a heat treatment method for eliminating room temperature parking effect of a 6000-series aluminum alloy, which comprises the following steps of: firstly, putting the 6000-series aluminum alloy into a heat preserving furnace, heating to 500-560 DEG C, preserving heat for 4-16 hours, then taking out the 6000-series aluminum alloy from the heat preserving furnace, and putting the 6000-series aluminum alloy into heat conducting oil for oil quenching; then taking out the 6000-series aluminum alloy from the heat conduction oil, and then putting the 6000-series aluminum alloy into water for water quenching; then putting the 6000-series aluminum alloy into an aging furnace, heating to 80-120 DEG C, and keeping the temperature for 2-8 hours; and finally, heating the 6000-series aluminum alloy in an aging furnace to 170-220 DEG C, preserving heat for 2-8 hours, taking out the 6000-series aluminum alloy, and carrying out air cooling to room temperature. According to the method, the tendency that Si-Si and Mg-Mg atomic clusters are formed between Si atoms and Mg atoms in the 6000-series aluminum alloy can be effectively inhibited, the room temperature parking effect of the traditional 6000-series aluminum alloy is effectively inhibited, and the peak aging strength of the 6000-series aluminum alloy is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy processing, and in particular relates to a heat treatment method for eliminating room temperature parking effect of 6000 series aluminum alloy. Background Art

[0002] 6000 series aluminum alloy is the most widely used type of deformed aluminum alloy. Commonly used models include 6063, 6061, 6082, 6005, 6056, 6069, 6013, etc. The application scope covers various fields of national economy such as doors and windows, curtain walls, industrial profiles, trusses, aviation rivets, ship profiles, etc. 6000 series aluminum alloy has an inherent defect, namely the room temperature parking effect. The so-called room temperature parking effect refers to the fact that after the solution treatment of 6000 series aluminum alloy, at room temperature, the supersaturated Si and Mg atoms in the solid solution will undergo short-range migration and segregation, forming Si-Si and Mg-Mg atomic clusters and gradually growing, replacing the generation of GP zone dominated by Si-Mg atom segregation, and manifesting as natural aging behavior of increased hardness and strength on a macro scale. When this natural aging behavior is fully developed, it will make it difficult for subsequent artificial aging to achieve the highest strength. Taking 6082 as an example, if the alloy is subjected to artificial aging treatment immediately after solution treatment, its tensile strength can reach 380MPa, while if the 6082 alloy after solution treatment is left at room temperature for 2 to 4 hours and then subjected to the same artificial aging treatment, its tensile strength is only 330MPa. In the actual production process, such as extrusion profiles, forging, rolling, etc., 6000 series aluminum alloy products or workpieces will inevitably be left for a period of time after solution treatment, or the production enterprises must leave them at room temperature until natural aging is stable before artificial aging treatment in order to ensure product quality stability. This results in the actual mechanical properties of 6000 series aluminum alloy materials being relatively low, and the performance potential of 6000 series aluminum alloys cannot be fully utilized. Summary of the invention

[0003] In view of the above shortcomings, the present invention discloses a heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy, which can effectively eliminate the room temperature parking effect of 6000 series aluminum alloy and improve the mechanical properties of 6000 series aluminum alloy materials.

[0004] The present invention is achieved by adopting the following technical solutions: A heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy comprises the following steps: (1) First-stage solution treatment: the 6000 series aluminum alloy is placed in a holding furnace and heated to 500-560°C and then kept at this temperature for 4-16 hours. The 6000 series aluminum alloy is then taken out of the holding furnace and placed in heat transfer oil for oil quenching for 30-60 minutes. (2) Second stage solid solution treatment: the 6000 series aluminum alloy treated in step (1) is taken out from the heat transfer oil, and then placed in water for water quenching. When the temperature of the 6000 series aluminum alloy drops to room temperature, it is taken out; (3) First artificial aging treatment: the 6000 series aluminum alloy treated in step (2) is placed in an aging furnace and heated to 80-120°C and then kept at this temperature for 2-8 hours; (4) Second artificial aging treatment: The 6000 series aluminum alloy treated in step (3) is heated in an aging furnace to a temperature of 170-220°C and then kept at that temperature for 2-8 hours. The 6000 series aluminum alloy is then taken out and air-cooled to room temperature.

[0005] Furthermore, the 6000 series aluminum alloy is a 6000 series aluminum alloy material and product containing any one or more of the rare earth elements Sc, Y, La, Ce, Er, Yb, and Ho, and the content of a single rare earth element is not less than 0.03%. The model of the 6000 series aluminum alloy can be any one of 6061, 6082, 6013, 6066, 6069, 6056, 6060, and 6005.

[0006] Furthermore, in step (1), the 6000 series aluminum alloy is placed in a heat preservation furnace and heated to 500-560° C. at a rate of 2-5° C. / min and then kept warm.

[0007] Furthermore, in step (1), the temperature of the heat transfer oil is 140-200°C.

[0008] Furthermore, in step (2), the temperature of water used in the water quenching process is 20 to 40°C.

[0009] Furthermore, after step (2) is completed, the 6000 series aluminum alloy can be stored at room temperature according to actual production conditions.

[0010] Furthermore, in step (3), the 6000 series aluminum alloy treated in step (2) is placed in an aging furnace and heated to 80 to 120° C. at a rate of 2 to 5° C. / min and then kept warm.

[0011] Furthermore, in step (4), the 6000 series aluminum alloy treated in step (3) is heated in an aging furnace at a rate of 2 to 5°C / min to a temperature of 170 to 220°C and then kept at this temperature.

[0012] Compared with the prior art, this technical solution has the following beneficial effects: 1. The present invention effectively inhibits the generation, segregation and growth of Si-Si and Mg-Mg atomic clusters in the saturated solid solution of 6000 series aluminum alloy by performing a two-stage solid solution treatment on the alloy. The first stage solid solution treatment mainly utilizes oil quenching and heat preservation in a heat transfer oil medium at 140-200°C to inhibit the generation of Si-Si and Mg-Mg atomic clusters, so that the Si and Mg atoms in the supersaturated solid solution of the alloy are in a disordered state, which is conducive to the formation of GP zone in the subsequent artificial aging process.

[0013] 2. The present invention effectively promotes the formation of GP zone and mainly enhances the generation of β' phase precipitates by performing double-stage artificial aging treatment on 6000 series aluminum alloy. The main principle is that Si-Si and Mg-Mg atomic clusters in 6000 series aluminum alloy treated by double-stage solid solution are suppressed, and a large number of β' phase precipitates are generated in the first stage of artificial aging, thereby improving the peak strength of artificial aging and eliminating the negative impact of room temperature parking effect. DETAILED DESCRIPTION

[0014] The present invention is further described by the following examples, but is not intended to be limiting of the present invention. Specific experimental conditions and methods not specified in the following examples are conventional methods commonly known to those skilled in the art.

[0015] Embodiment 1: Taking 6082 aluminum alloy as an example, its main components are: Si: 0.98%, Mg: 1.02%, Mn: 0.83%, Cr: 0.14%, Ti: 0.03%, Fe: 0.16%, the balance is Al, and the content of other individual impurities is ≤0.05%, and the total amount of impurities is ≤0.15; after smelting, casting and extrusion, a profile blank is obtained, and then the profile blank is heat treated according to the method of the present invention, which comprises the following steps: (1) First-stage solution treatment: The 6082 series aluminum alloy is placed in a holding furnace and heated to 545°C at a rate of 3°C / min and then kept at this temperature for 616 hours. The 6082 series aluminum alloy is then taken out of the holding furnace and placed in heat transfer oil at a temperature of 160°C for oil quenching for 45 minutes. (2) Second stage solution treatment: the 6082 series aluminum alloy treated in step (1) is taken out from the heat transfer oil, and then placed in water at a temperature of 25°C for water quenching. When the temperature of the 6082 series aluminum alloy drops to room temperature, it is taken out; The 6082 series aluminum alloy is left at room temperature for 2 days; (3) First artificial aging treatment: the 6082 series aluminum alloy treated in step (2) is placed in an aging furnace and heated to 90°C at a rate of 3°C / min and then kept at this temperature for 4 hours; (4) Second artificial aging treatment: The 6082 series aluminum alloy treated in step (3) is heated to 200°C in an aging furnace at a rate of 3°C / min and then kept at this temperature for 4 hours. The 6082 series aluminum alloy is then taken out and air-cooled to room temperature.

[0016] Example 2: Taking 6013 aluminum alloy as an example, its main components are: Si: 0.82%, Mg: 1.09%, Cu: 0.89%, Mn: 0.65%, Zn: 0.18%, Cr: 0.09%, Ti: 0.03%, Fe: 0.24%, the balance is Al, and the content of other individual impurities is ≤0.05%, and the total amount of impurities is ≤0.15; after smelting, casting and extrusion, a profile blank is obtained, and then the profile blank is heat treated according to the method of the present invention, which includes the following steps: (1) First-stage solution treatment: The 6013 series aluminum alloy is placed in a holding furnace and heated to 535°C at a rate of 4°C / min and then kept at this temperature for 8 hours. The 6013 series aluminum alloy is then taken out of the holding furnace and placed in heat transfer oil at a temperature of 180°C for oil quenching for 45 minutes. (2) Second stage solid solution treatment: the 6013 series aluminum alloy treated in step (1) is taken out from the heat transfer oil, and then placed in water at a temperature of 25°C for water quenching. When the temperature of the 6013 series aluminum alloy drops to room temperature, it is taken out; The 6013 series aluminum alloy is left at room temperature for 4 days; (3) First artificial aging treatment: the 6013 series aluminum alloy treated in step (2) is placed in an aging furnace and heated to 100°C at a rate of 4°C / min and then kept at that temperature for 3 hours; (4) Second artificial aging treatment: The 6013 series aluminum alloy treated in step (3) is heated in an aging furnace at a rate of 3°C / min to 185°C and then kept at that temperature for 8 hours. The 6013 series aluminum alloy is then taken out and air-cooled to room temperature.

[0017] Embodiment 3: Taking 6056 aluminum alloy as an example, its main components are: Si: 1.17%, Mg: 0.98%, Cu: 0.92%, Mn: 0.76%, Zn: 0.59%, Cr: 0.17%, Ti: 0.03%, Zr: 0.13%, Fe: 0.31%, the balance is Al, and the content of other individual impurities is ≤0.05%, and the total amount of impurities is ≤0.15; after smelting, casting and extrusion, a profile blank is obtained, and then the profile blank is heat treated according to the method of the present invention, which comprises the following steps: (1) First-stage solution treatment: The 6056 series aluminum alloy is placed in a holding furnace and heated to 540°C at a rate of 3°C / min and then kept at this temperature for 6 hours. The 6056 series aluminum alloy is then taken out of the holding furnace and placed in heat transfer oil at a temperature of 160°C for oil quenching for 45 minutes. (2) Second stage solution treatment: the 6056 series aluminum alloy treated in step (1) is taken out from the heat transfer oil, and then placed in water at a temperature of 25°C for water quenching. When the temperature of the 6056 series aluminum alloy drops to room temperature, it is taken out; The 6056 series aluminum alloy is left at room temperature for 1 day; (3) First artificial aging treatment: the 6056 series aluminum alloy treated in step (2) is placed in an aging furnace and heated to 95°C at a rate of 3°C / min and then kept at this temperature for 5 hours; (4) Second artificial aging treatment: The 6056 series aluminum alloy treated in step (3) is heated in an aging furnace at a rate of 3°C / min to 190°C and then kept at that temperature for 6 hours. The 6056 series aluminum alloy is then taken out and air-cooled to room temperature.

[0018] Example 4: Taking the 6082 aluminum alloy described in Example 1 as an example, a profile blank is obtained after smelting, casting and extrusion, and then the profile blank is heat treated according to the method of the present invention, which includes the following steps: (1) First-stage solution treatment: The 6082 series aluminum alloy is placed in a holding furnace and heated to 500°C at a rate of 2°C / min and then kept at this temperature for 16 hours. The 6082 series aluminum alloy is then taken out of the holding furnace and placed in heat transfer oil at a temperature of 140°C for oil quenching for 30 minutes. (2) Second stage solid solution treatment: the 6082 series aluminum alloy treated in step (1) is taken out from the heat transfer oil, and then placed in water at a temperature of 20°C for water quenching. When the temperature of the 6082 series aluminum alloy drops to room temperature, it is taken out; The 6082 series aluminum alloy is left at room temperature for half a day; (3) First artificial aging treatment: the 6082 series aluminum alloy treated in step (2) is placed in an aging furnace and heated at a rate of 2°C / min to 80°C and then kept at that temperature for 8 hours; (4) Second artificial aging treatment: The 6082 series aluminum alloy treated in step (3) is heated to 170°C in an aging furnace at a rate of 2°C / min and then kept at this temperature for 8 hours. The 6082 series aluminum alloy is then taken out and air-cooled to room temperature.

[0019] Example 5: Taking the 6013 aluminum alloy described in Example 2 as an example, a profile blank is obtained after smelting, casting and extrusion, and then the profile blank is heat treated according to the method of the present invention, which includes the following steps: (1) First-stage solution treatment: The 6013 series aluminum alloy is placed in a holding furnace and heated to 560°C at a rate of 5°C / min and then kept at this temperature for 4 hours. Then, the 6012 series aluminum alloy is taken out of the holding furnace and placed in heat transfer oil at a temperature of 200°C for oil quenching for 60 minutes. (2) Second stage solid solution treatment: the 6012 series aluminum alloy treated in step (1) is taken out from the heat transfer oil, and then placed in water at a temperature of 40°C for water quenching. When the temperature of the 6013 series aluminum alloy drops to room temperature, it is taken out; The 6013 series aluminum alloy is left at room temperature for 1 day; (3) First artificial aging treatment: the 6013 series aluminum alloy treated in step (2) is placed in an aging furnace and heated at a rate of 5°C / min to 120°C and then kept at this temperature for 2 hours; (4) Second artificial aging treatment: The 6013 series aluminum alloy treated in step (3) is heated in an aging furnace at a rate of 5°C / min to 220°C and then kept at this temperature for 2 hours. The 6013 series aluminum alloy is then taken out and air-cooled to room temperature.

[0020] Comparative Example 1: Take the 6082 aluminum alloy described in Example 1, and obtain a profile blank after melting, casting and extrusion. Then, the profile blank is treated by the conventional T6 heat treatment process for deformed aluminum alloys and cast aluminum alloys, wherein the profile blank is kept at 545°C for 6 hours and then water quenched, then left at room temperature for 2 days, and then kept at 175°C for 8 hours for peak aging.

[0021] Comparative Example 2: Take the 6013 aluminum alloy described in Example 2, and obtain a profile blank after melting, casting and extrusion. Then, the profile blank is treated by the conventional T6 heat treatment process for deformed aluminum alloys and cast aluminum alloys, wherein the profile blank is kept at 535°C for 8 hours and then water quenched, then left at room temperature for 4 days, and then kept at 175°C for 8 hours for peak aging.

[0022] Comparative Example 3: Take the 6056 aluminum alloy described in Example 3, and obtain a profile blank after melting, casting and extrusion. Then, the profile blank is treated by the conventional T6 heat treatment process for deformed aluminum alloys and cast aluminum alloys, wherein the profile blank is kept at 540°C for 6 hours and then water quenched, then left at room temperature for 1 day, and then kept at 175°C for 8 hours for peak aging.

[0023] Experimental Example: The aluminum alloys treated according to the methods described in Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to room temperature mechanical tests. The test results are shown in Table 1.

[0024] Table 1 Performance test results of aluminum alloys treated by different methods

[0025] It can be seen from Table 1 that the aluminum alloy obtained by the method of the present invention has good yield strength, tensile strength and elongation.

[0026] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy, characterized in that: The following steps are involved: (1) First-stage solution treatment: the 6000 series aluminum alloy is placed in a holding furnace and heated to 500-560°C and then kept at this temperature for 4-16 hours. The 6000 series aluminum alloy is then taken out of the holding furnace and placed in heat transfer oil for oil quenching for 30-60 minutes. (2) Second stage solid solution treatment: the 6000 series aluminum alloy treated in step (1) is taken out from the heat transfer oil, and then placed in water for water quenching. When the temperature of the 6000 series aluminum alloy drops to room temperature, it is taken out; (3) First artificial aging treatment: the 6000 series aluminum alloy treated in step (2) is placed in an aging furnace and heated to 80-120°C and then kept at this temperature for 2-8 hours; (4) Second artificial aging treatment: The 6000 series aluminum alloy treated in step (3) is heated in an aging furnace to a temperature of 170-220°C and then kept at that temperature for 2-8 hours. The 6000 series aluminum alloy is then taken out and air-cooled to room temperature.

2. The heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy according to claim 1, characterized in that: The 6000 series aluminum alloy is a 6000 series aluminum alloy material and product containing any one or more of the rare earth elements Sc, Y, La, Ce, Er, Yb, and Ho, and the content of a single rare earth element is not less than 0.03%.

3. The heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy according to claim 1, characterized in that: In step (1), the 6000 series aluminum alloy is placed in a heat preservation furnace and heated to 500-560° C. at a rate of 2-5° C. / min and then kept warm.

4. The heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy according to claim 1, characterized in that: In step (1), the temperature of the heat transfer oil is 140-200°C.

5. The heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy according to claim 1, characterized in that: In step (2), the temperature of water used in the water quenching process is 20 to 40°C.

6. The heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy according to claim 1, characterized in that: After step (2) is completed, the 6000 series aluminum alloy can be stored at room temperature according to actual production conditions.

7. The heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy according to claim 1, characterized in that: In step (3), the 6000 series aluminum alloy treated in step (2) is placed in an aging furnace and heated to 80 to 120° C. at a rate of 2 to 5° C. / min and then kept warm.

8. The heat treatment method for eliminating the room temperature parking effect of 6000 series aluminum alloy according to claim 1, characterized in that: In step (4), the 6000 series aluminum alloy treated in step (3) is heated in an aging furnace at a rate of 2 to 5°C / min to a temperature of 170 to 220°C and then kept at this temperature.

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