Heat treatment method for improving structure and performance of 7xxx series aluminum alloy

A heat treatment method and technology for aluminum alloys are applied in the heat treatment to improve the microstructure and properties of 7xxx series aluminum alloys, and in the field of heat treatment of 7xxx series aluminum alloys, which can solve the problems of large quenching residual stress and excessive machining deformation of alloy structural parts. The effect of reducing quenching residual stress, improving production efficiency, and strong operability

Active Publication Date: 2021-06-29
GRIMAT ENG INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Adopting the fastest possible quenching and cooling rate is beneficial to obtain higher strength, but at the same time it will bring larger quenching residual stress, which is easy to cause problems such as out-of-tolerance machining deformation of alloy structural parts

Method used

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  • Heat treatment method for improving structure and performance of 7xxx series aluminum alloy
  • Heat treatment method for improving structure and performance of 7xxx series aluminum alloy
  • Heat treatment method for improving structure and performance of 7xxx series aluminum alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] In this embodiment, a 25mm plate of 7055 alloy (Al-8.0Zn-2.3Cu-2.0Mg-0.16Zr) is used as the research object. The solution treatment system of the hot-rolled 7055 alloy plate is 470°C / 2h+475°C / 2h, the pre-stretch deformation is 2.0%, and different schemes of staged quenching and single-stage aging heat treatment are adopted. The heat treatment system is shown in Table 3 . The properties of the plates after different heat treatments were tested, and the results are shown in Table 4.

[0038] table 3

[0039]

[0040] Table 4

[0041]

Embodiment 2

[0043] In this embodiment, a 78mm plate of 7050 alloy (Al-6.2Zn-2.3Cu-2.2Mg-0.12Zr) is used as the research object. The solution treatment system of the hot-rolled 7055 alloy plate is 470°C / 3h+480°C / 1h, the pre-stretch deformation is 2.3%, and different schemes of staged quenching and single-stage aging heat treatment are adopted. The heat treatment system is shown in Table 5 . The properties of the plates after different heat treatments were tested, and the results are shown in Table 6.

[0044] table 5

[0045]

[0046] Table 6

[0047]

Embodiment 3

[0049] In this embodiment, a 152mm plate of 7085 alloy (Al-7.5Zn-1.6Cu-1.5Mg-0.12Zr) is used as the research object. The solution treatment system of the hot-rolled 7085 alloy plate is 475°C / 2h, and the pre-stretching deformation is 2.5%. Different schemes of staged quenching and single-stage aging heat treatment are adopted. The heat treatment system is shown in Table 7. The properties of the plates after different heat treatments were tested, and the results are shown in Table 8.

[0050] Table 7

[0051]

[0052] Table 8

[0053]

[0054]

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Abstract

Provided is a heat treatment method for improving the structure and performance of a 7xxx series aluminum alloy. The method includes the steps that firstly, single-stage or graded solid solution heat preservation heat treatment is conducted on a deformation form, and the final solid solution heat preservation temperature is T1, wherein T1 is greater than or equal to 460 DEG C and less than or equal to 485 DEG C; the alloy is cooled from T1 to T2 at an average cooling rate V1, and then from T2 to room temperature at an average cooling rate V2, wherein T2 is greater than or equal to 150 DEG C and less than or equal to 190 DEG C, V1 is greater than or equal to 20 DEG C / s and less than or equal to 60 DEG C / s, and V2 is greater than or equal to 3 DEG C / s and less than or equal to 10 DEG C / s; and 1-5% of cold deformation treatment is conducted on the quenched aluminum alloy, and then aging heat treatment is conducted at the temperature T3 for the heat preservation time t1, wherein T3 is greater than or equal to 110 DEG C and less than or equal to 140 DEG C, and t1 is greater than or equal to 10 h and less than or equal to 32 h. According to the heat treatment method for improving the structure and performance of the 7xxx series aluminum alloy, under the condition that the residual stress is controlled, the 7xxx series aluminum alloy can obtain an ideal precipitated phase structure form, and good matching of obdurability and corrosion resistance is obtained. Compared with the prior art, the method greatly shortens the heat treatment time, and has the characteristics of simplicity and convenience in operation, high efficiency and feasibility.

Description

technical field [0001] The invention relates to a heat treatment method for 7xxx series (Al-Zn-Mg-Cu series) aluminum alloys, more specifically, relates to a heat treatment method for improving the microstructure and performance of 7xxx series aluminum alloys, and belongs to the technical field of aluminum alloy heat treatment. Background technique [0002] 7xxx series (Al-Zn-Mg-Cu series) aluminum alloys are typical heat-treated aluminum alloys that can be strengthened. Solution, quenching, pre-stretching and aging treatment are the key process steps to obtain the ideal uniform structure and excellent comprehensive properties of the alloy. In order to obtain the 7xxx series aluminum alloy with good comprehensive properties, it is required that the strengthening elements of the alloy fully dissolve back into the matrix during solution treatment; after aging treatment, the alloy finally forms small, numerous and densely distributed intragranular precipitates , and grain bound...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22F1/053
CPCC22F1/053C22F1/002
Inventor 李锡武熊柏青温凯李志辉李亚楠张永安闫丽珍闫宏伟刘红伟
Owner GRIMAT ENG INST CO LTD
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