A short process heat treatment method for casting Al-Mg-Si series aluminum alloy

Abstract

The application discloses a short-process heat treatment method for casting Al-Mg-Si series aluminum alloy, and belongs to the technical field of metal materials and preparation. Compared with a traditional complicated preparation process of "casting-homogenization-solid solution-aging", the heat treatment method provided by the application adopts a combination mode of solid solution treatment and different aging treatments, wherein the solid solution and aging temperatures gradually increase, so that the heat treatment holding time is greatly shortened, the aluminum alloy plate is prepared in a short process, cost and energy are saved, and the strength and hardness performance of the aluminum alloy plate is greatly improved.

Description

Technical Field

[0001] This application relates to the field of metallic materials and preparation technology, and in particular to a short-process heat treatment method for casting Al-Mg-Si aluminum alloys. Background Technology

[0002] Modern automobiles are developing towards lightweighting, high speed, safety, comfort, low cost, and energy conservation. Currently, the most effective solution is to reduce the overall weight of the vehicle, which requires more systematic and in-depth research in areas such as automotive structural design, material selection, and optimization. Lightweight alloys such as aluminum and magnesium alloys, compared to traditional iron-carbon alloys, have advantages such as lower density and higher specific strength, making them the preferred materials for achieving automotive lightweighting. Cast aluminum alloys, typical Al-Si alloys, possess excellent casting properties, such as good fluidity, low linear shrinkage, and no tendency for hot cracking, allowing for the casting of relatively complex shapes. Furthermore, with appropriate heat treatment, an ideal combination of high strength, good plasticity, and impact toughness can be achieved. Therefore, aluminum alloys are now widely used in casting automotive subframes.

[0003] Cast aluminum alloys typically require a complex manufacturing process (casting-homogenization-solution-aging) in actual production, resulting in low production efficiency. Therefore, there is an urgent need for a shorter process that is simpler, more efficient, and produces alloys that meet performance requirements after heat treatment. Summary of the Invention

[0004] Existing technologies suffer from problems such as excessively long aluminum alloy preparation processes, high energy consumption, insufficient strength, and significant differences in corrosion resistance.

[0005] In view of this, the purpose of this application is to propose a novel short-process aluminum alloy heat treatment process based on the existing foundation. The new process adopts a combination of solution treatment and different aging treatments, in which the solution and aging temperatures are gradually increased to significantly shorten the heat treatment holding time, realize the short-process preparation of aluminum alloy plates, save costs and energy, and greatly improve the strength and hardness properties of the aluminum alloy plates.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] In a first aspect, embodiments of this application provide a short-process heat treatment method for casting Al-Mg-Si aluminum alloys, comprising three stages: solution treatment, water quenching, and aging treatment; the process parameters for the solution treatment stage are a temperature of 530–550°C and a holding time of 5–7 h; the water quenching stage is located between the solution treatment stage and the aging treatment stage, and the process parameters for the water quenching stage are 50–80°C, the aluminum alloy transfer time after the solution treatment is not more than 0.5 min, and the water quenching time is 1.5 min; the temperature range for the aging treatment is 60–220°C, and the holding time is 3–6 h.

[0008] Furthermore, the time-sensitive processing is any one of the following (1) to (4):

[0009] (1) Medium-temperature aging treatment, wherein the process parameters of the medium-temperature aging treatment are 150-180℃ and heat preservation for 4-6 hours;

[0010] (2) High-temperature aging treatment, wherein the process parameters for the high-temperature aging treatment are 190-220℃ and heat preservation for 3-5 hours;

[0011] (3) Two-stage aging treatment, the two-stage aging treatment includes two temperature aging treatment processes, in the order of the two temperature aging treatments, the process parameters of the two temperature aging treatments are 100~120℃, holding for 1~2h and 170~190℃, holding for 2~4h respectively;

[0012] (4) Intermittent aging treatment, which includes three temperature aging treatment processes. The process parameters for the three temperature aging treatments are 150-180℃ for 0.5-1h, 60-80℃ for 1.5-3h, and 170-190℃ for 1-2h, respectively.

[0013] Furthermore, the temperature rise efficiency in the solution treatment stage is 10℃ / min, and the temperature rise rate in the aging treatment stage is 5℃ / min.

[0014] Secondly, embodiments of this application provide an Al-Mg-Si aluminum alloy, which is prepared by the aforementioned short-process heat treatment method.

[0015] Further, the Al-Mg-Si aluminum alloy comprises the following components by mass percentage: Si 6.5%–7.50%, Mg 0.25%–0.45%, Ti 0.05%–0.25%, Mn 0.05%–0.10%, Fe 0.10%–0.20%, Zn <0.10%, Cu 0.01%–0.06%, total impurity element content <0.25%, and the balance being Al.

[0016] Thirdly, embodiments of this application provide an application of the aforementioned short-process heat treatment method in the preparation of Al-Mg-Si aluminum alloys.

[0017] This application provides a short-process heat treatment method for casting Al-Mg-Si aluminum alloys, which has at least the following advantages compared with the prior art:

[0018] Compared with the traditional single-stage process, this process refines the solution treatment and aging treatment stages. The step-by-step heating aging takes into account the initial precipitation and high-temperature precipitation stages, which maximizes the precipitation strengthening effect of the alloy and makes the alloy have excellent comprehensive mechanical properties. Attached Figure Description

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the invention. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0020] Figure 1 This is a flowchart of the heat treatment process for the medium-temperature aging treatment used in Embodiment 1 of this application.

[0021] Figure 2 This is a flowchart of the heat treatment process for high-temperature aging treatment used in Embodiment 2 of this application.

[0022] Figure 3 This is a flowchart of the heat treatment process using the two-stage aging process employed in Embodiment 3 of this application.

[0023] Figure 4 This is a flowchart of the heat treatment process using intermittent aging treatment in Embodiment 4 of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] For the purpose of better understanding this application and not limiting its scope, all figures and other numerical values ​​used herein to indicate quantities, percentages, or other values ​​should, in all cases, be understood to be modified by the word "approximately." Therefore, unless otherwise stated, the numerical parameters listed in the specification and appended claims are approximate values ​​and may vary depending on the desired properties being sought. Each numerical parameter should at least be considered as obtained based on the reported significant figures and through conventional rounding methods.

[0026] The ambient temperature mentioned in the following embodiments of this application refers to the natural room temperature conditions in all four seasons, without additional cooling or heating treatment. The ambient temperature is generally controlled between 10 and 30°C, preferably between 15 and 25°C.

[0027] In this embodiment, the solution treatment and aging treatment equipment is a high-temperature resistance furnace, such as the KSL-1200x box-type high-temperature sintering furnace, and the water quenching treatment equipment is a water tank with temperature control equipment. In this embodiment, the term "transfer time" refers to the interval between when the aluminum alloy material is taken out of the high-temperature resistance furnace and put into the water tank for water quenching treatment at the end of the solution treatment.

[0028] In the embodiments of this application, the term "β″" or "β′" represents a transition phase. During the aging process, Mg2Si is the most important strengthening phase, and its precipitation process is as follows: α supersaturated solid solution → GP region → β″ transition phase → β' transition phase → β stable phase. At lower aging temperatures, the α supersaturated solid solution is obtained during the solution treatment, and Mg and Si atoms form a weakly dense atom segregation region, namely the GP(Ⅰ) region. At higher aging temperatures, solute atoms can bypass the GP(Ⅱ) region and directly form a semi-coherent β' transition phase. Therefore, the appropriate temperature for the aging process is around 180°C, and the aging process can obtain better strength and hardness.

[0029] This application embodiment refines the solution treatment stage and aging treatment stage in the heat treatment process of cast aluminum alloys. By adopting a step-by-step heating and aging method, it fully considers the initial precipitation and high-temperature precipitation stages in the aluminum alloy casting process. This heat treatment process not only maximizes the precipitation strengthening effect of aluminum alloys, but also significantly improves the mechanical properties of the alloys, such as strength and hardness.

[0030] Based on this, this application provides a short-process heat treatment method for casting Al-Mg-Si aluminum alloys, comprising three stages: solution treatment, water quenching, and aging treatment; the process parameters for the solution treatment stage are a temperature of 530–550°C and a holding time of 5–7 h; the water quenching stage is located between the solution treatment stage and the aging treatment stage, and the process parameters for the water quenching stage are 50–80°C, the aluminum alloy transfer time after the solution treatment is no more than 0.5 min, and the water quenching time is 1.5 min; the process parameters for the aging treatment are 60–220°C and a holding time of 4–7 h.

[0031] In some embodiments, the aging treatment is a medium-temperature aging treatment, wherein the process parameters for the medium-temperature aging treatment are 150–180°C and the holding time is 4–6 hours. In some preferred embodiments, the process parameters for the medium-temperature aging treatment are 180°C and the holding time is 4–6 hours.

[0032] In some embodiments, the aging treatment is a high-temperature aging treatment, with process parameters of 190–220°C and holding time of 3–5 hours. In some preferred embodiments, the process parameters of the medium-temperature aging treatment are 220°C and holding time of 3–5 hours.

[0033] In some embodiments, the aging treatment is a two-stage aging treatment, comprising two temperature aging processes. The process parameters for the two temperature aging processes, in sequence, are 100–120°C for 1–2 hours and 170–190°C for 2–4 hours, respectively. In some preferred embodiments, the aging treatment is a two-stage aging treatment, comprising two temperature aging processes. The process parameters for the two temperature aging processes, in sequence, are 120°C for 1–2 hours and 190°C for 2–4 hours, respectively.

[0034] In some embodiments, the aging treatment is an intermittent aging treatment, which includes three temperature aging treatment processes in sequence. The process parameters for the three temperature aging treatments are 150–180°C, holding for 0.5–1 h; 60–80°C, holding for 2–3 h; and 170–190°C, holding for 2–4 h. In some preferred embodiments, the aging treatment is an intermittent aging treatment, which includes three temperature aging treatment processes in sequence. The process parameters for the three temperature aging treatments are 180°C, holding for 0.5–1 h; 80°C, holding for 2–3 h; and 190°C, holding for 2–4 h.

[0035] In some embodiments, the temperature rise efficiency in the solution treatment stage is 10°C / min, and the temperature rise rate in the aging treatment stage is 5°C / min.

[0036] Based on this, this application provides an Al-Mg-Si aluminum alloy, which is prepared by the aforementioned short-process heat treatment method.

[0037] In some embodiments, the Al-Mg-Si aluminum alloy is available through ordinary commercial channels and comprises the following components by mass percentage: 6.5%–7.50% Si, 0.25%–0.45% Mg, 0.05%–0.25% Ti, 0.05%–0.10% Mn, 0.10%–0.20% Fe, <0.10% Zn, 0.01%–0.06% Cu, <0.25% total impurity elements, and the balance being Al.

[0038] Based on this, this application also provides an application of the aforementioned short-process heat treatment method in the preparation of Al-Mg-Si aluminum alloys.

[0039] The present application will be further described below with reference to more specific embodiments. Of course, the following embodiments should not be construed as limiting the present application.

[0040] 1. Main experimental equipment

[0041] KSL-1200x box-type high-temperature sintering furnace: PID control, temperature control range: room temperature to 1200℃; ordinary heating water bath, temperature control range: room temperature to 100℃; ETM-305D microcomputer-controlled electronic universal testing machine.

[0042] 2. Experimental materials

[0043] This application uses ZL101A aluminum alloy as the experimental raw material, which can be purchased through ordinary commercial channels. ZL101A aluminum alloy is currently the main material for manufacturing aluminum wheels for automobiles. This alloy has excellent casting performance, good fluidity, low linear shrinkage, low tendency to hot cracking, and good airtightness. In the following embodiments and comparative examples, the ZL101A aluminum alloy is a 20mm diameter bar. The aluminum alloy comprises the following components by mass percentage: Si 6.5%–7.50%, Mg 0.25%–0.45%, Ti 0.05%–0.25%, Mn 0.05%–0.10%, Fe 0.10%–0.20%, Zn content <0.10%, Cu 0.01%–0.06%, total impurity element content <0.25%, and the balance being Al.

[0044] 3. Experimental Methods

[0045] The qualified ZL101A aluminum alloy produced in batches was placed in a KSL-1200x box-type high-temperature sintering furnace for heat treatment processes such as solution treatment, water quenching, and aging treatment. After heat treatment, the aluminum alloy billets were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine to further verify their mechanical properties. The tensile test method was carried out in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method.

[0046] Example 1

[0047] Figure 1 The heat treatment process diagram used in this embodiment is as follows: a 20mm diameter bar is cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, were selected, with the furnace temperature fluctuation range controlled within ±1℃. The cut aluminum alloy billets were placed in sintering furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 was raised from room temperature to 550℃ at a rate of 10℃ / min. After maintaining the temperature of 550℃ in sintering furnace No. 1 for 5 hours, the aluminum alloy billets were removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing the billets from the furnace to transferring them into the hot water bath was controlled within 30 seconds, and the water temperature was controlled at around 50-80℃. The quenching time of the aluminum alloy billets in the hot water bath was controlled within 1.5 minutes. After removing the aluminum alloy billets from the hot water bath, the surface water was wiped dry, and then the billets were placed in sintering furnace No. 2. Sintering furnace No. 2 was set to heat up to 180℃ and hold for 4-6 hours for aging treatment, with a heating rate of 5℃ / min. After the aging treatment is completed, the aluminum alloy billet is taken out from the No. 2 sintering furnace and placed in an atmospheric environment to cool naturally to room temperature.

[0048] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0049] Example 2

[0050] Figure 2The heat treatment process diagram used in this embodiment is as follows: a 20mm diameter bar is cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, were selected, with the furnace temperature fluctuation range controlled within ±1℃. The cut aluminum alloy billets were placed in sintering furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 was raised from room temperature to 545℃ at a rate of 10℃ / min. After maintaining the temperature of 545℃ in sintering furnace No. 1 for 6 hours, the aluminum alloy billets were removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing the billets from the furnace to transferring them into the hot water bath was controlled within 30 seconds, and the water temperature was controlled at around 50-80℃. The quenching time of the aluminum alloy billets in the hot water bath was controlled within 1.5 minutes. After removing the aluminum alloy billets from the hot water bath, the surface water was wiped dry, and then the billets were placed in sintering furnace No. 2. Sintering furnace No. 2 was set to be heated to 220℃ and held for 3-5 hours for aging treatment, with a heating rate of 5℃ / min. After the aging treatment is completed, the aluminum alloy billet is taken out from the No. 2 sintering furnace and placed in an atmospheric environment to cool naturally to room temperature.

[0051] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0052] Example 3

[0053] Figure 3The heat treatment process used in this embodiment is as follows: A 20mm diameter bar is cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x tubular heat treatment furnace or a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, are selected, with the furnace temperature fluctuation range controlled within ±1℃. The cut aluminum alloy billet is placed in sintering furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 is raised from room temperature to 540℃ at a rate of 10℃ / min. After maintaining the temperature at 540℃ in sintering furnace No. 1 for 7 hours, the aluminum alloy billet is removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing the billet from the furnace to transferring it into the hot water bath is controlled within 30 seconds, and the water temperature is controlled at 50℃. At approximately 80℃, the aluminum alloy billet is quenched in a hot water bath for 1.5 minutes. After removing the billet from the hot water bath and wiping off any water, it is placed back into sintering furnace No. 2. The temperature control program for furnace No. 2 is set as follows: heat to 120℃ and hold for 1–2 hours, then heat to 190℃ and hold for 2–4 hours, with a heating rate of 5℃ / min. After the aging treatment, the aluminum alloy billet is removed from furnace No. 2 and allowed to cool naturally to room temperature in an atmospheric environment.

[0054] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0055] Example 4

[0056] Figure 4The heat treatment process used in this embodiment is as follows: A 20mm diameter bar is cut from a ZL101A cast aluminum alloy billet and processed in a KSL-1200x tubular heat treatment furnace or a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, are selected, with the furnace temperature fluctuation range controlled within ±1℃. The cut aluminum alloy billet is placed in sintering furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 is raised from room temperature to 530℃ at a rate of 10℃ / min. After maintaining the temperature of sintering furnace No. 1 at 530℃ for 7 hours, the aluminum alloy billet is removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing the billet from the furnace to transferring it into the hot water bath is controlled within 30 seconds, and the water temperature is controlled at approximately 50-80℃. The quenching time in the hot water bath is controlled at 1.5 minutes. After removing the aluminum alloy billet from the hot water bath, wipe the surface water off the billet and place it into sintering furnace No. 2. The temperature control program for sintering furnace No. 2 is set as follows: heat to 180℃ and hold for 0.5-1 hour, cool to 60-80℃ and hold for 1.5-3 hours, then heat to 190℃ and hold for 1-2 hours. The heating rate of furnace No. 2 is 5℃ / min. After the aging treatment is completed, remove the aluminum alloy billet from sintering furnace No. 2 and allow it to cool naturally to room temperature in an atmospheric environment.

[0057] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0058] Comparative Example 1

[0059] This comparative example can refer to the heat treatment process of Example 1. Except for the parameter settings in the aging treatment stage, the other parameters and conditions are the same. Specifically, a 20mm diameter bar is cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, were selected, with the furnace temperature fluctuation range controlled within ±1℃. The cut aluminum alloy billets were placed in sintering furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 was raised from room temperature to 550℃ at a rate of 10℃ / min. After maintaining the temperature of 550℃ in sintering furnace No. 1 for 7 hours, the aluminum alloy billets were removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing the billets from the furnace to transferring them into the hot water bath was controlled within 30 seconds, and the water temperature was controlled at around 0-80℃. The quenching time of the aluminum alloy billets in the hot water bath was controlled within 1.5 minutes. After removing the aluminum alloy billets from the hot water bath, the surface water was wiped dry, and then the billets were placed in sintering furnace No. 2. Sintering furnace No. 2 was set to heat up to 120℃ and hold for 4-6 hours for aging treatment, with a heating rate of 5℃ / min. After the aging treatment is completed, the aluminum alloy billet is taken out from the No. 2 sintering furnace and placed in an atmospheric environment to cool naturally to room temperature.

[0060] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0061] Comparative Example 2

[0062] This comparative example can refer to the heat treatment process of Example 1. Except for the difference in the aging treatment stage time, the other parameters and conditions are the same. Specifically, a 20mm diameter bar is cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, were selected, with the furnace temperature fluctuation range controlled within ±1℃. The cut aluminum alloy billets were placed in sintering furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 was raised from room temperature to 550℃ at a rate of 10℃ / min. After maintaining the temperature of 550℃ in sintering furnace No. 1 for 7 hours, the aluminum alloy billets were removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing the billets from the furnace to transferring them into the hot water bath was controlled within 30 seconds, and the water temperature was controlled at around 50-80℃. The quenching time of the aluminum alloy billets in the hot water bath was controlled within 1.5 minutes. After removing the aluminum alloy billets from the hot water bath, the surface water was wiped dry, and then the billets were placed in sintering furnace No. 2. Sintering furnace No. 2 was set to heat up to 120℃ and hold for 10 hours for aging treatment. The heating rate of furnace No. 2 was 5℃ / min. After the aging treatment is completed, the aluminum alloy billet is taken out from the No. 2 sintering furnace and placed in an atmospheric environment to cool naturally to room temperature.

[0063] Comparative Example 3

[0064] This comparative example can refer to the heat treatment process of Example 3, except that the aging treatment stage time is different, and other parameters and conditions are the same. Specifically, 20mm diameter bars are cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x tubular heat treatment furnace or a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, are selected, and the furnace temperature fluctuation range is controlled within ±1℃. The cut aluminum alloy billet is placed in heat treatment furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 is raised from room temperature to 540℃ at a heating rate of 10℃ / min. After maintaining 540℃ in sintering furnace No. 1 for 7 hours, the aluminum alloy billet is removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing it from the furnace to transferring it into the hot water bath is controlled within 30 seconds, and the water temperature is controlled at [temperature range missing]. The aluminum alloy billet is quenched in a hot water bath at approximately 50–80℃ for 1.5 minutes. After removing the billet from the hot water bath and wiping off any water, it is placed back into sintering furnace No. 2. The temperature control program for furnace No. 2 is set as follows: heat to 80℃ and hold for 2 hours, then heat to 160℃ and hold for 4 hours, with a heating rate of 5℃ / min. After the aging treatment, the aluminum alloy billet is removed from furnace No. 2 and allowed to cool naturally to room temperature in an atmospheric environment.

[0065] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0066] Comparative Example 4

[0067] This comparative example can refer to the heat treatment process of Example 3, except that the aging treatment stage time is different, and other parameters and conditions are the same. Specifically, 20mm diameter bars are cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x tubular heat treatment furnace or a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, are selected, and the furnace temperature fluctuation range is controlled within ±1℃. The cut aluminum alloy billet is placed in heat treatment furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 is raised from room temperature to 540℃ at a heating rate of 10℃ / min. After maintaining 540℃ in sintering furnace No. 1 for 7 hours, the aluminum alloy billet is removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing it from the furnace to transferring it into the hot water bath is controlled within 30 seconds, and the water temperature is controlled at [temperature range missing]. The aluminum alloy billet is quenched in a hot water bath at approximately 50–80℃ for 1.5 minutes. After removing the billet from the hot water bath and wiping off any water, it is placed in sintering furnace No. 2. The temperature control program for furnace No. 2 is set as follows: heat to 80℃ and hold for 3 hours, then heat to 160℃ and hold for 5 hours, with a heating rate of 5℃ / min. After the aging treatment, the aluminum alloy billet is removed from furnace No. 2 and allowed to cool naturally to room temperature in an atmospheric environment.

[0068] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0069] Comparative Example 5

[0070] This comparative example can refer to the heat treatment process of Example 4, except that the aging treatment stage time is different, and other parameters and conditions are the same. Specifically, 20mm diameter bars are cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x tubular heat treatment furnace or a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, are selected, and the furnace temperature fluctuation range is controlled within ±1℃. The cut aluminum alloy billet is placed in heat treatment furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 is raised from room temperature to 530℃ at a rate of 10℃ / min. After maintaining 530℃ in sintering furnace No. 1 for 7 hours, the aluminum alloy billet is removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing it from the furnace to transferring it into the hot water bath is controlled within 30 seconds, and the water temperature is controlled between 50 and 80℃. The quenching time of the aluminum alloy billet in the hot water bath was controlled at 1.5 minutes. After removing the aluminum alloy billet from the hot water bath, the surface water was wiped dry, and then it was placed in sintering furnace No. 2. The temperature control program of sintering furnace No. 2 was set as follows: heat up to 90℃ and hold for 1 hour, cool down to 50℃ and hold for 3 hours, and then heat up to 160℃ and hold for 2 hours. The heating rate of furnace No. 2 was 5℃ / min. After the aging treatment, the aluminum alloy billet was removed from sintering furnace No. 2 and allowed to cool naturally to room temperature in an atmospheric environment.

[0071] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0072] Comparative Example 6

[0073] This comparative example can refer to the heat treatment process of Example 4, except that the aging treatment stage time is different, and other parameters and conditions are the same. Specifically, 20mm diameter bars are cut from the ZL101A cast aluminum alloy billet and processed in a KSL-1200x tubular heat treatment furnace or a KSL-1200x box-type high-temperature sintering furnace with a rated power of 4kW. Two sintering furnaces, No. 1 and No. 2, are selected, and the furnace temperature fluctuation range is controlled within ±1℃. The cut aluminum alloy billet is placed in heat treatment furnace No. 1 for solution treatment. The furnace temperature of sintering furnace No. 1 is raised from room temperature to 530℃ at a rate of 10℃ / min. After maintaining 530℃ in sintering furnace No. 1 for 7 hours, the aluminum alloy billet is removed from sintering furnace No. 1 and placed in a hot water bath for quenching. The time from removing it from the furnace to transferring it into the hot water bath is controlled within 30 seconds, and the water temperature is controlled between 50 and 80℃. The quenching time of the aluminum alloy billet in the hot water bath was controlled at 1.5 minutes. After removing the aluminum alloy billet from the hot water bath, the surface water was wiped dry, and then it was placed in sintering furnace No. 2. The temperature control program of sintering furnace No. 2 was set as follows: heat up to 90℃ and hold for 2 hours, cool down to 50℃ and hold for 3 hours, and then heat up to 160℃ and hold for 3 hours. The heating rate of furnace No. 2 was 5℃ / min. After the aging treatment, the aluminum alloy billet was removed from sintering furnace No. 2 and allowed to cool naturally to room temperature in an atmospheric environment.

[0074] The heat-treated aluminum alloy blanks were subjected to room temperature tensile tests using an ETM-305D microcomputer-controlled electronic universal testing machine. The test method was in accordance with GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method, with a tensile rate of 2 mm / min.

[0075] The hardness of the aluminum alloy samples obtained in Examples 1-4 and Comparative Examples 1-6 was measured using a Vickers hardness tester with a load of 10 kgf and a holding time of 30 s.

[0076] The data from tensile tests and hardness measurements of the aluminum alloy samples obtained in Examples 1-4 and Comparative Examples 1-6 are shown in Table 1 below.

[0077] Table 1

[0078]

[0079] Results analysis: (1) By comparing Examples 1-4 with Comparative Examples 1-6, the aluminum alloy of Example 3 has the highest tensile strength and hardness, with values ​​of 298 MPa and 121 HV respectively, while the aluminum alloy of Example 4 has the highest yield strength and elongation after fracture, with values ​​of 250.1 MPa and 9.3% respectively.

[0080] (2) By comparing the mechanical properties and hardness results of aluminum alloys in Example 1 with those in Comparative Examples 1 and 2, the strength properties and hardness results of aluminum alloys in Example 3 with those in Comparative Examples 3 and 4, and the strength properties and hardness results of aluminum alloys in Example 4 with those in Comparative Examples 5 and 6, it can be seen that when the aging temperature is lower than that of the embodiments of this application, the mechanical strength and hardness are significantly lower than those of the aluminum alloys in each embodiment. By extending the aging time, the strength and hardness of the aluminum alloy can be improved, but they are still lower than those of the aluminum alloys obtained in each embodiment. It can be seen that the temperature range in the aging treatment provided in the embodiments of this application is the optimal choice. The aluminum alloy obtained by using the heat treatment technology provided in the embodiments of this application can not only improve the comprehensive mechanical properties, but also shorten the heat treatment time and reduce energy consumption.

[0081] (3) The short-process heat treatment technology provided in this application, compared with the traditional solution treatment process, ensures that the multiphase eutectic structure can significantly improve the solubility of Mg in the matrix without overheating, thereby increasing the number density of subsequent aging-induced strengthening phases. The stepwise heating aging treatment mode divides the precipitation of aluminum alloy into preliminary precipitation and high-temperature precipitation stages. The first-stage aging treatment uses a relatively low temperature and a short time. Under these conditions, a large number of Mg2Si atomic clusters can be formed in the grains. At the same time, the difference between the diffusion energy of the grains and the grain boundaries is widened, causing the precipitates near the original grain boundaries to grow rapidly. The second-stage aging treatment uses a relatively high temperature and a short time. Under these conditions, the Mg2Si clusters in the grains can grow rapidly to form β″ or β′. At the same time, the precipitates at the grain boundaries grow further, greatly improving the mechanical properties of the alloy. By strictly controlling the temperature and time of the aging treatment, the generation and distribution of the second phase in the cast aluminum alloy can be well controlled, giving the alloy excellent comprehensive mechanical properties.

[0082] The present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are only for the purpose of helping to understand the invention and its core ideas. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A short-process heat treatment method for casting Al-Mg-Si aluminum alloys, characterized in that, include: The process consists of three stages: solution treatment, water quenching, and aging treatment. The solution treatment stage has a temperature of 530–550℃ and a holding time of 5–7 hours. The water quenching stage occurs between the solution treatment and aging treatment stages, with a temperature of 50–80℃. After solution treatment, the aluminum alloy transfer time should not exceed 0.5 minutes, and the water quenching time is 1.5 minutes. The aging treatment has a temperature range of 60–220℃ and a holding time of 3–6 hours. The aging treatment is an intermittent aging treatment, which includes three temperature aging treatment processes. In order, the process parameters for the three temperature aging treatments are 180℃ for 0.5-1h, 60-80℃ for 1.5-3h, and 190℃ for 1-2h. The temperature rise efficiency in the solution treatment stage is 10℃ / min, and the temperature rise rate in the aging treatment stage is 5℃ / min. The Al-Mg-Si aluminum alloy comprises the following components by mass percentage: Si 6.5%–7.50%, Mg 0.25%–0.45%, Ti 0.05%–0.25%, Mn 0.05%–0.10%, Fe 0.10%–0.20%, Zn <0.10%, Cu 0.01%–0.06%, total impurity element content <0.25%, and the balance being Al.

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