High-strength aluminum alloy treatment process

Abstract

The invention discloses a high-strength aluminum alloy treatment process which comprises the following steps: A, carrying out stress relief annealing on an aluminum alloy workpiece subjected to cold plastic deformation at the annealing temperature of 300-400 DEG C for 1-2 hours; b, under the protective atmosphere, the treated workpiece is heated to the first-stage solid solution temperature at the first heating rate V1, heat preservation is conducted for t1 time, then the treated workpiece is heated to the second-stage solid solution temperature at the second heating rate V2, heat preservation is conducted for t2 time, V2 is larger than V1, and the sum of the solid solution heat preservation time t1 and t2 is larger than 1.5 h; c, the workpiece subjected to solution treatment is quenched; the method is convenient for improving the efficiency and reducing the energy consumption, and the quenching transfer time of the 6-series wrought aluminum alloy is greatly shortened, so that the occurrence frequency of soft spots of parts can be reduced, and the problem that the parts with unqualified hardness are scrapped is further reduced.

Description

Technical Field

[0001] This invention specifically relates to a high-strength aluminum alloy processing technology. Background Technology

[0002] Compared to conventional steel car bodies, all-aluminum car bodies typically reduce weight by more than 30%, which undoubtedly improves fuel efficiency and driving performance. While aluminum alloys offer advantages in terms of lightness and corrosion resistance, their load-bearing capacity under high loads is a significant disadvantage. Currently, there is a high market demand for high-strength, high-hardness aluminum alloys, but traditional 6-series wrought aluminum alloys cannot meet these load-bearing requirements. Therefore, we propose a high-strength aluminum alloy processing technology. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength aluminum alloy processing technology to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a high-strength aluminum alloy processing technology, comprising the following steps:

[0005] Step A: Perform stress-relief annealing on the aluminum alloy workpiece after cold plastic deformation. The annealing temperature is 300-400℃, and the holding time is 1-2 hours.

[0006] Step B: The treated workpiece is heated to the first stage solution temperature at a first heating rate V1 under a protective atmosphere and held at that temperature for a time t1. Then, it is heated to the second stage solution temperature at a second heating rate V2 and held at that temperature for a time t2, where V2 is greater than V1. The sum of the solution holding times t1 and t2 is greater than 1.5 hours.

[0007] Step C: Transfer the workpiece that has completed the solution treatment within 20 seconds for quenching, and then perform a second heat treatment in a multi-stage aging furnace after quenching.

[0008] Step D: Cool the workpiece to room temperature at a controlled rate after heat preservation.

[0009] Preferably, the solution temperature of the first stage is H1, 500℃ < H1 < 510℃, and the solution temperature of the second stage is H2, 520℃ < H2 < 540℃.

[0010] Preferably, the first heating rate V1 is 1-3℃ / min, and the second heating rate V2 is 3-5℃ / min.

[0011] Preferably, the quenching medium is polyvinylpyrrolidone, and the concentration of the polyvinylpyrrolidone is 5%-15%, and the cooling rate during the quenching process is greater than 200℃ / s when the workpiece temperature is above 300℃.

[0012] Preferably, in step C, the quenched workpiece is first held at a first aging temperature of 115℃-135℃ for 3-5 hours, and then heated to a second aging temperature of 165℃-185℃ for 5-8 hours.

[0013] Preferably, in step B, the gas under the protective atmosphere is a neutral gas.

[0014] Preferably, in step C, the temperature after quenching is below 100°C.

[0015] Preferably, the aluminum alloy comprises the following microalloying elements by weight: Zr: 5-15 parts, Ag: 5-20 parts, Sn: 1-10 parts.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This invention improves efficiency and reduces energy consumption. By significantly shortening the quenching transfer time of 6-series wrought aluminum alloys, it reduces the frequency of soft spots in parts, thereby reducing the problem of scrapping parts due to insufficient hardness. Furthermore, the use of a protective atmosphere and water-based media for quenching ensures the uniformity of the product's surface and internal structure. Through multi-stage artificial aging and composite solution treatment, it achieves high density, fine spheroidization, and uniform distribution of micro-precipitates, which helps to ensure the tensile strength and hardness of the aluminum alloy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0019] 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.

[0020] Example 1

[0021] Please see Figure 1 This invention provides a technical solution: a high-strength aluminum alloy processing technology, comprising the following steps:

[0022] Step A: Perform stress-relief annealing on the aluminum alloy workpiece after cold plastic deformation. The annealing temperature is 300-400℃, and the holding time is 1-2 hours.

[0023] It facilitates the optimization of the initial state of the material through stress-relief annealing;

[0024] Step B: The treated workpiece is heated to the first stage solution temperature at a first heating rate V1 under a protective atmosphere and held at that temperature for a time t1. Then, it is heated to the second stage solution temperature at a second heating rate V2 and held at that temperature for a time t2, where V2 is greater than V1. The sum of the solution holding times t1 and t2 is greater than 1.5 hours.

[0025] By using a protective atmosphere to reduce oxidation, controlling the dezincification or demagnesification of the surface, the surface quality of the aluminum alloy is guaranteed. Furthermore, through a two-stage heating mechanism, the precursor of the precipitated phase is synergistically regulated to ensure the quality of the aluminum alloy.

[0026] Step C: Transfer the workpiece that has completed the solution treatment within 20 seconds for quenching, and then perform a second heat treatment in a multi-stage aging furnace after quenching.

[0027] Step D: Cool the workpiece to room temperature at a controlled rate after heat preservation;

[0028] This allows for the proactive and precise control of the evolution of the micro-precipitated phases within the aluminum alloy, thereby achieving ideal comprehensive performance with both strength and toughness.

[0029] Preferably, the solution temperature of the first stage is H1, 500℃ < H1 < 510℃, and the solution temperature of the second stage is H2, 520℃ < H2 < 540℃.

[0030] Preferably, the first heating rate V1 is 1-3℃ / min, and the second heating rate V2 is 3-5℃ / min.

[0031] Preferably, the quenching medium is polyvinylpyrrolidone, and the concentration of the polyvinylpyrrolidone is 5%-15%, and the cooling rate during the quenching process is greater than 200℃ / s when the workpiece temperature is above 300℃.

[0032] Preferably, in step C, the quenched workpiece is first held at a first aging temperature of 115℃-135℃ for 3-5 hours, and then heated to a second aging temperature of 165℃-185℃ for 5-8 hours.

[0033] At the relatively low temperature of the first aging stage, atomic diffusion ability is limited, but the driving force for nucleation is large. The main products of this stage are extremely fine GP regions and early nuclei of the β'' phase. After the temperature is increased in the second aging stage, atomic diffusion ability is enhanced. At this time, the numerous GP regions and β'' phase nuclei formed in the first aging stage begin to absorb surrounding solute atoms Mg and Si and grow to form a high-density, fine and uniformly distributed β'' strengthening phase.

[0034] The primary strengthening mechanism of the 6-series aluminum alloys (Al-Mg-Si series) in this invention is age hardening, which involves heat treatment to induce the precipitation of nanoscale, coherent strengthening phases within the supersaturated solid solution. These phases impede dislocation movement, thereby increasing the material's strength and hardness. The precipitation sequence is typically: supersaturated solid solution → atomic clusters → GP zones → β'' phase → β' phase → β phase (Mg2Si).

[0035] β'' phase: The most critical strengthening phase, in the form of needles or rods, is completely coherent with the aluminum matrix and can generate an extremely strong coherent strain field, which is the core for obtaining high peak strength; β' phase: A metastable phase, semi-coherent with the matrix, it is larger in size and its strengthening effect is not as good as the β'' phase, but if it coarsens excessively, it will lead to a decrease in the strength and hardness of the alloy; β phase: A stable equilibrium phase, coarse and incoherent with the matrix, it does not contribute to strength, but may instead impair toughness.

[0036] Preferably, in step B, the gas under the protective atmosphere is a neutral gas;

[0037] The neutral gas used in this invention is preferably nitrogen.

[0038] Preferably, in step C, the temperature after quenching is below 100°C.

[0039] Preferably, the aluminum alloy comprises the following microalloying elements by weight: Zr: 5-15 parts, Ag: 5-20 parts, Sn: 1-10 parts;

[0040] Microalloying elements, such as Zr, Ag, and Sn, can be added to form nanoscale reinforcing phases, thereby improving the mechanical strength properties of the product.

[0041] Example 2

[0042] This invention provides a technical solution: a high-strength aluminum alloy processing technology, comprising the following steps:

[0043] Step A: Perform stress-relief annealing on the aluminum alloy workpiece after cold plastic deformation. The annealing temperature is 300-400℃, and the holding time is 1-2 hours.

[0044] Step B: Heat the treated workpiece to a solution temperature of 515-535℃ and hold for 1.5-2.5 hours;

[0045] Step C: Transfer the solution-treated workpiece to the quenching medium within 20 seconds for quenching, and then transfer the quenched workpiece to an aging furnace at 165-185℃ for artificial aging for 7-9 hours.

[0046] Step D: Cool the aged workpiece to room temperature at a controlled rate.

[0047] Example of effect:

[0048] The changes in hardness of 6-series aluminum alloys at different temperatures are as follows:

[0049]

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-strength aluminum alloy processing technology, characterized in that, Includes the following steps: Step A: Perform stress-relief annealing on the aluminum alloy workpiece after cold plastic deformation. The annealing temperature is 300-400℃, and the holding time is 1-2 hours. Step B: The treated workpiece is heated to the first stage solution temperature at a first heating rate V1 under a protective atmosphere and held at that temperature for a time t1. Then, it is heated to the second stage solution temperature at a second heating rate V2 and held at that temperature for a time t2, where V2 is greater than V1. The sum of the solution holding times t1 and t2 is greater than 1.5 hours. Step C: Transfer the workpiece that has completed the solution treatment within 20 seconds for quenching, and then perform a second heat treatment in a multi-stage aging furnace after quenching. Step D: Cool the workpiece to room temperature at a controlled rate after heat preservation.

2. The high-strength aluminum alloy processing technology according to claim 1, characterized in that: The solution temperature in the first stage is H1, 500℃ < H1 < 510℃, and the solution temperature in the second stage is H2, 520℃ < H2 < 540℃.

3. The high-strength aluminum alloy processing technology according to claim 1, characterized in that: The first heating rate V1 is 1-3℃ / min, and the second heating rate V2 is 3-5℃ / min.

4. The high-strength aluminum alloy processing technology according to claim 1, characterized in that: The quenching medium is polyvinylpyrrolidone, and the concentration of polyvinylpyrrolidone is 5%-15%. The cooling rate during the quenching process is greater than 200℃ / s when the workpiece temperature is above 300℃.

5. The high-strength aluminum alloy processing technology according to claim 1, characterized in that: In step C, the quenched workpiece is first held at a first aging temperature of 115℃-135℃ for 3-5 hours, and then heated to a second aging temperature of 165℃-185℃ for 5-8 hours.

6. The high-strength aluminum alloy processing technology according to claim 1, characterized in that: In step B, the gas under the protective atmosphere is a neutral gas.

7. The high-strength aluminum alloy processing technology according to claim 1, characterized in that: In step C, the temperature after quenching is below 100°C.

8. The high-strength aluminum alloy processing technology according to claim 1, characterized in that: The aluminum alloy contains the following microalloying elements by weight: Zr: 5-15 parts, Ag: 5-20 parts, Sn: 1-10 parts.

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