Preparation method of 6110A aluminum alloy bar for automobile forging

Abstract

The invention discloses a preparation method of a 6110A aluminum alloy bar for automobile forging, and belongs to the field of aluminum alloy bar machining. The method comprises the following steps: heating a pure aluminum ingot to 720-740 DEG C for melting, uniformly dispersing an intermediate alloy in a Sudoku position, putting the intermediate alloy into a smelting furnace, stirring, refining, degassing, filtering and casting to obtain an aluminum alloy ingot, carrying out three-stage homogenization treatment on the ingot, carrying out low-temperature extrusion on the homogenized ingot, carrying out on-line solution treatment on an extruded bar, and carrying out high-temperature treatment on the extruded bar to obtain the aluminum alloy. And then spray quenching is carried out, and aging treatment is carried out after quenching. The intermediate alloy is put in a Sudoku mode, and a three-section homogenization process is combined, so that the grain size grade of the prepared aluminum alloy bar can reach more than 7 grades; low-temperature extrusion is adopted, and heating solution treatment is carried out after extrusion, so that the thickness of a coarse grain layer on the surface of the bar is smaller than 0.2 mm, heat energy consumption is reduced by about 30%, the tensile strength is larger than or equal to 410 MPa, the yield strength is larger than or equal to 385 MPa, and the percentage elongation after fracture is larger than or equal to 10%.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy bar processing, specifically relating to a method for preparing 6110A aluminum alloy bars for automotive forging. Background Technology

[0002] With the deepening trend of automotive lightweighting, aluminum alloys are increasingly used in high-strength structural components such as chassis and suspension systems, including control arms and steering knuckles. 6110A alloy, due to its good strength, toughness, and formability, has become an ideal candidate material for automotive forgings. However, existing production processes for 6110A aluminum alloy bars used in automotive forging suffer from difficulties in grain refinement during the casting process. During casting, the centralized feeding of the aluminum master alloy easily leads to uneven distribution of alloying elements in the melt, resulting in segregation and coarse, uneven grains, which affects subsequent processing performance and the mechanical properties of the final product.

[0003] Therefore, there is an urgent need to develop a preparation method that can stabilize and refine grains, suppress the formation of coarse grain layers, and achieve energy saving. Summary of the Invention

[0004] This invention aims to overcome the shortcomings of existing technologies and provide a method for preparing 6110A aluminum alloy bars for automotive forging. This method optimizes the melting, casting, homogenization, extrusion, and heat treatment processes, achieving grain refinement, coarse grain layer control, and energy conservation and consumption reduction in the production process.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for preparing 6110A aluminum alloy bars for automotive forging, wherein the components and their weight percentages in the aluminum alloy bars are as follows:

[0007] The Si content is 0.75%-1.05%;

[0008] The Mg content is 0.85%-1.15%;

[0009] The Cu content is 0.25%-0.45%;

[0010] The Mn content is 0.15%-0.35%;

[0011] The Zr content is 0.08%-0.18%;

[0012] The Ti content is 0.04%-0.08%;

[0013] The Fe content is ≤0.08%;

[0014] The Cr content is ≤0.08%;

[0015] The total content of other individual impurity elements is ≤0.03%, with the balance being Al;

[0016] The method for preparing the 6110A aluminum alloy bar for automotive forging includes:

[0017] S1. Melting and casting and online processing: Pure aluminum ingots are put into a melting furnace and heated to 720-740℃ to melt. Then, alloy raw materials are put into the melting furnace and stirred, refined, degassed, filtered and cast to obtain aluminum alloy ingots.

[0018] S2. Three-stage ingot homogenization treatment: The ingot is subjected to three-stage heating and staged room temperature resting homogenization treatment.

[0019] S3. Extrusion forming and online solution aging: The homogenized ingot is heated to 390-410℃ for extrusion. The extruded bar is subjected to online solution treatment, followed by quenching, and then aging treatment.

[0020] The addition of Cu can significantly reduce the quenching sensitivity of the alloy, allowing the core of the extruded bar to form a supersaturated solid solution during quenching, thereby improving the mechanical properties of the extruded bar.

[0021] Zr is the core element of this design. During the casting and homogenization process of extruded bars, Zr forms extremely fine nanoparticles with extremely high thermal stability. In the subsequent bar extrusion and forging preheating process, Zr can strongly pin the grain boundaries and subgrain boundaries.

[0022] Mn, by forming a dispersed phase, synergistically inhibits recrystallization and grain growth with Zr. Ti refines the grains during the casting stage, resulting in a uniform and fine as-cast microstructure and reducing macroscopic segregation.

[0023] Fe is the most common harmful impurity in aluminum alloys. The Fe content is strictly limited to ≤0.08%, far below the general standard. The aim is to minimize the formation of coarse acicular phases and reduce the initiation of microcracks.

[0024] Low-temperature extrusion at 390-410℃ can reduce the deformation resistance of metals, decrease the tendency for grain growth, and effectively control the formation of coarse-grained layers. At the same time, the lower temperature can also improve the surface quality and dimensional accuracy of the bars.

[0025] As a further supplement to the present invention, the charging port of the melting furnace is divided into a 9-grid pattern. Each alloy raw material is divided into 9 parts according to the weight of the components and mixed. The raw materials are then fed into the melting furnace at the corresponding 9-grid positions to avoid the intermediate alloy from being concentrated in a certain area, which would result in the local alloy composition being too high or too low.

[0026] As a further supplement to the present invention, in step S2, the three-stage ingot homogenization treatment specifically includes:

[0027] (1) First stage: Heat to 300-320℃ at 100-120℃ / h, keep warm for 4-6 hours, then remove from the furnace and let stand at room temperature for 8-10 hours. In this stage, the lower temperature and longer holding time can allow the solute atoms in the ingot to diffuse slowly, eliminate some casting stress, and prepare for subsequent grain refinement and homogenization treatment.

[0028] (2) Second stage: Heat to 420-440℃ at 130-150℃ / h, hold for 4-6 hours, then remove from the furnace and let stand at room temperature for 8-10 hours. The diffusion rate of solute atoms is accelerated, the grain boundary migration and recrystallization process can be fully carried out, the grains are further refined and homogenized, and at the same time, some coarse second phase particles begin to dissolve, further improving the uniformity of the alloy structure.

[0029] (3) Third stage: Heat to 520-540℃ at 150-170℃ / h, hold for 6-8 hours, then slowly cool to 200-220℃ at a rate of 80-100℃ / h, and air cool to room temperature after removal from the furnace. During the cooling process, avoid the ingot being subjected to violent airflow impact to prevent the generation of new stress, and ensure the stability and uniformity of the grains. Air cooling can quickly cool the ingot to room temperature, ensuring the microstructure after homogenization treatment.

[0030] As a further supplement to the present invention, in step S3, the extruded bar is subjected to online solution treatment. The inlet temperature of the bar is controlled at 350-370℃ and the outlet temperature is controlled at 540-560℃. The solution treatment time is 8-10 minutes. After solution treatment, the bar is sprayed and quenched, and then aged at 175℃ for 8 hours.

[0031] By precisely controlling the temperature and residence time of the bars in the online solution furnace, the full dissolution of the strengthening phases and the homogenization of the solid solution in 6110A aluminum alloy are achieved, while avoiding grain growth and mechanical property degradation caused by overheating or burning. The inlet temperature is controlled at 350-370℃ to ensure uniform heating of the bars and gradual attainment of the solution critical temperature, preventing local overheating that could lead to the melting of low-melting-point eutectic phases. The outlet temperature is maintained at 540-560℃ to ensure that the strengthening phases (such as nano-precipitates) are completely integrated into the solid solution, forming a supersaturated solid solution, laying the foundation for subsequent aging strengthening. The 8-10 minute solution time ensures the full decomposition of the strengthening phases while avoiding grain boundary weakening or distortion that may be caused by prolonged holding.

[0032] As a further supplement to the present invention, the extrusion speed is controlled at 0.8-1m / min, and the diameter of the extruded bar is 80-100mm.

[0033] The extruded bar, carrying the residual heat from the extrusion, is transported to an online continuous heating solution furnace for solution treatment. This ensures that the second phase in the alloy is fully dissolved into the aluminum matrix to form a supersaturated solid solution. Compared with the traditional method of cooling before solution treatment after extrusion, this method significantly reduces energy consumption.

[0034] As a further supplement to the present invention, the 6110A aluminum alloy bar for automotive forging achieves grain refinement and effective control of the coarse grain layer through optimized melting, casting, homogenization, extrusion and heat treatment processes. The production process is energy-saving and consumption-reducing, and the obtained bar has a grain size grade ≥ 7; a coarse grain layer thickness of less than 0.2 mm; tensile strength ≥ 410 MPa, yield strength ≥ 385 MPa, and elongation after fracture ≥ 10%.

[0035] The beneficial effects of this invention are as follows:

[0036] By employing a nine-square grid for intermediate alloy input and combining it with a three-stage homogenization process, compositional segregation is effectively eliminated, and the grain size grade of the prepared aluminum alloy rods can reach level 7 or above.

[0037] The material is extruded at a low temperature of 380-420℃, followed by a solution treatment at a higher temperature. This significantly reduces the temperature rise during deformation and the tendency for grain growth, resulting in a coarse grain layer thickness of less than 0.2 mm on the surface of the bar, reducing heat consumption by about 30%. The tensile strength is ≥410 MPa, the yield strength is ≥385 MPa, and the elongation after fracture is ≥10%.

[0038] The beneficial effects of this invention are as follows:

[0039] 1. By adopting a nine-square grid for intermediate alloy input and combining it with a three-stage homogenization process, compositional segregation is effectively eliminated, and the grain size grade of the prepared aluminum alloy rods can reach level 7 or above.

[0040] 2. Low-temperature extrusion at 380-420℃ is adopted, followed by heat treatment to significantly reduce the deformation temperature rise and grain growth tendency, resulting in a coarse grain layer thickness of less than 0.2mm on the surface of the bar, tensile strength ≥410 MPa, yield strength ≥385 MPa, and elongation after fracture ≥10%. Attached Figure Description

[0041] Figure 1 This is a grain size classification diagram from Example 1 of the present invention;

[0042] Figure 2 This is a diagram showing the thickness of the coarse-grained layer in Embodiment 1 of the present invention;

[0043] Figure 3 This is a grain size classification diagram from Example 2 of the present invention;

[0044] Figure 4 This is a diagram showing the thickness of the coarse-grained layer in Embodiment 2 of the present invention;

[0045] Figure 5 This is a grain size classification diagram for Example 3 of the present invention;

[0046] Figure 6 This is a diagram showing the thickness of the coarse-grained layer in Embodiment 3 of the present invention;

[0047] Figure 7 This is a grain size classification diagram for Comparative Example 1 of the present invention;

[0048] Figure 8 This is a diagram showing the coarse-grained layer thickness in Comparative Example 1 of the present invention;

[0049] Figure 9 This is a grain size classification diagram for Comparative Example 2 of the present invention;

[0050] Figure 10 This is a diagram showing the coarse-grained layer thickness in Comparative Example 2 of the present invention;

[0051] Figure 11 This is a grain size classification diagram for Comparative Example 3 of the present invention;

[0052] Figure 12 This is a diagram showing the thickness of the coarse-grained layer in Comparative Example 3 of the present invention. Detailed Implementation

[0053] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0054] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described herein are only some embodiments of the present invention and are not intended to limit the present invention. All other embodiments implemented by those skilled in the art based on the embodiments of the present invention without creative improvements are within the protection scope of the present invention.

[0055] Example 1: The components and their weight percentages in the aluminum alloy are as follows:

[0056] The Si content is 0.95%;

[0057] The Mg content is 1.0%;

[0058] The Cu content is 0.3%;

[0059] The Mn content is 0.25%;

[0060] The Zr content is 0.12%;

[0061] The Ti content is 0.06%;

[0062] The Fe content is 0.06%;

[0063] The Cr content is 0.06%;

[0064] The total content of other individual impurity elements is ≤0.03%, with the balance being Al;

[0065] This invention provides a method for preparing 6110A aluminum alloy bars for automotive forging, comprising the following steps:

[0066] S1. Melting and casting and online processing: Pure aluminum ingots are put into the melting furnace and heated to 730℃ to melt. The furnace feed port is divided into a 9-grid pattern. Each alloy raw material is divided into 9 parts according to the weight of the components and mixed. The parts are put into the melting furnace at the corresponding 9-grid positions. After stirring, refining, degassing, filtering and casting, aluminum alloy ingots are obtained.

[0067] S2. Three-stage ingot homogenization treatment: The ingot undergoes a three-stage heating and staged room temperature resting homogenization treatment, specifically as follows:

[0068] (1) First stage: Heat to 310℃ at 110℃ / h, hold for 5 hours, then remove from the furnace and let stand at room temperature for 9 hours. In this stage, the lower temperature and longer holding time can allow solute atoms in the ingot to diffuse slowly, eliminate some casting stress, and prepare for subsequent grain refinement and homogenization treatment.

[0069] (2) Second stage: The temperature is raised to 430℃ at 140℃ / h, and after holding at the temperature for 5 hours, it is taken out of the furnace and left at room temperature for 9 hours. The diffusion rate of solute atoms is accelerated, the grain boundary migration and recrystallization process can be fully carried out, the grains are further refined and homogenized, and at the same time, some coarse second phase particles begin to dissolve, further improving the uniformity of the alloy structure.

[0070] (3) Third stage: Heat to 530℃ at 160℃ / h, hold for 7 hours, then slowly cool to 210℃ at a rate of 90℃ / h, and air cool to room temperature after removal from the furnace. During the cooling process, avoid the ingot being subjected to violent airflow impact to generate new stress, and ensure the stability and uniformity of the grains. Air cooling can quickly cool the ingot to room temperature, ensuring the microstructure after homogenization treatment.

[0071] S3. Extrusion Molding and Online Solution Aging: The homogenized ingot is heated to 400℃ and extruded at a speed of 0.9 m / min to produce a 90 mm diameter bar. The extruded bar undergoes online solution treatment at an inlet temperature of 360℃ and an outlet temperature of 550℃ for 9 minutes. After solution treatment, the bar is spray-quenched and then aged at 175℃ for 8 hours.

[0072] Example 2: The components and their weight percentages in the aluminum alloy are as follows:

[0073] The Si content is 0.75%;

[0074] The Mg content is 0.85%;

[0075] The Cu content is 0.25%;

[0076] The Mn content is 0.15%;

[0077] The Zr content is 0.08%;

[0078] The Ti content is 0.04%;

[0079] The Fe content is 0.04%;

[0080] The Cr content is 0.04%;

[0081] The total content of other individual impurity elements is ≤0.03%, with the balance being Al;

[0082] This invention provides a method for preparing 6110A aluminum alloy bars for automotive forging, comprising the following steps:

[0083] S1. Melting and casting and online processing: Pure aluminum ingots are put into the melting furnace and heated to 720℃ to melt. The furnace feed port is divided into a 9-grid pattern. Each alloy raw material is divided into 9 parts according to the weight of the components and mixed. The parts are put into the melting furnace at the corresponding 9-grid positions. After stirring, refining, degassing, filtering and casting, aluminum alloy ingots are obtained.

[0084] S2. Three-stage ingot homogenization treatment: The ingot undergoes a three-stage heating and staged room temperature resting homogenization treatment, specifically as follows:

[0085] (1) First stage: Heat to 300℃ at 100℃ / h, keep warm for 6 hours, then remove from the furnace and let stand at room temperature for 10 hours. In this stage, the lower temperature and longer holding time can allow the solute atoms in the ingot to diffuse slowly, eliminate some casting stress, and prepare for subsequent grain refinement and homogenization treatment.

[0086] (2) Second stage: The temperature is raised to 420℃ at 130℃ / h, and after holding at the temperature for 6 hours, the furnace is removed and left at room temperature for 10 hours. The diffusion rate of solute atoms is accelerated, the grain boundary migration and recrystallization process are fully carried out, the grains are further refined and homogenized, and at the same time, some coarse second phase particles begin to dissolve, further improving the uniformity of the alloy structure.

[0087] (3) Third stage: Heat to 520℃ at 150℃ / h, hold for 6 hours, then slowly cool to 200℃ at a rate of 80℃ / h, and air cool to room temperature after removal from the furnace. During the cooling process, avoid the ingot being subjected to violent airflow impact to generate new stress, and ensure the stability and uniformity of the grains. Air cooling can quickly cool the ingot to room temperature, ensuring the microstructure after homogenization treatment.

[0088] S3. Extrusion Molding and Online Solution Aging: The homogenized ingot is heated to 390℃ and extruded at a speed controlled at 0.8 m / min. The diameter of the extruded bar is 80 mm. The extruded bar undergoes online solution treatment. The inlet temperature of the solution furnace is 350℃, the outlet temperature is 540℃, and the solution treatment time is 8 min. After solution treatment, the bar is spray-quenched and then aged at 175℃ for 8 h.

[0089] Example 3: The components and their weight percentages in the aluminum alloy are as follows:

[0090] The Si content is 1.05%;

[0091] The Mg content is 1.15%;

[0092] The Cu content is 0.45%;

[0093] The Mn content is 0.35%;

[0094] The Zr content is 0.18%;

[0095] The Ti content is 0.08%;

[0096] The Fe content is 0.08%;

[0097] The Cr content is 0.08%;

[0098] The total content of other individual impurity elements is ≤0.03%, with the balance being Al;

[0099] This invention provides a method for preparing 6110A aluminum alloy bars for automotive forging, comprising the following steps:

[0100] S1. Melting and casting and online processing: Pure aluminum ingots are put into the melting furnace and heated to 740℃ to melt. The furnace feed port is divided into a 9-grid pattern. Each alloy raw material is divided into 9 parts according to the weight of the components and mixed. The parts are put into the melting furnace at the corresponding 9-grid positions. After stirring, refining, degassing, filtering and casting, aluminum alloy ingots are obtained.

[0101] S2. Three-stage ingot homogenization treatment: The ingot undergoes a three-stage heating and staged room temperature resting homogenization treatment, specifically as follows:

[0102] (1) First stage: Heat to 320℃ at 120℃ / h, keep warm for 4 hours, then remove from the furnace and let stand at room temperature for 8 hours. In this stage, the lower temperature and longer holding time can allow solute atoms in the ingot to diffuse slowly, eliminate some casting stress, and prepare for subsequent grain refinement and homogenization treatment.

[0103] (2) Second stage: The temperature is raised to 440℃ at 150℃ / h, and after holding at the temperature for 4 hours, the furnace is removed and left at room temperature for 8 hours. The diffusion rate of solute atoms is accelerated, the grain boundary migration and recrystallization process are fully carried out, the grains are further refined and homogenized, and at the same time, some coarse second phase particles begin to dissolve, further improving the uniformity of the alloy structure.

[0104] (3) Third stage: Heat to 540℃ at 170℃ / h, hold for 8 hours, then slowly cool to 220℃ at a rate of 100℃ / h, and air-cool to room temperature after removal from the furnace. During the cooling process, avoid the ingot being subjected to violent airflow impact to prevent the generation of new stress, and ensure the stability and uniformity of the grains. Air cooling can quickly cool the ingot to room temperature, ensuring the microstructure after homogenization treatment.

[0105] S3. Extrusion Molding and Online Solution Aging: The homogenized ingot is heated to 410℃ and extruded at a speed of 1m / min to produce a 100mm diameter bar. The extruded bar undergoes online solution treatment at an inlet temperature of 370℃ and an outlet temperature of 560℃ for 10 minutes. After solution treatment, the bar is spray-quenched and then aged at 175℃ for 8 hours.

[0106] Comparative Example 1: The components and their weight percentages in the aluminum alloy are as follows:

[0107] The Si content is 0.95%;

[0108] The Mg content is 1.0%;

[0109] The Cu content is 0.3%;

[0110] The Mn content is 0.25%;

[0111] The Zr content is 0.12%;

[0112] The Ti content is 0.06%;

[0113] The Fe content is 0.06%;

[0114] The Cr content is 0.06%;

[0115] The total content of other individual impurity elements is ≤0.03%, with the balance being Al;

[0116] A method for preparing 6110A aluminum alloy bars for automotive forging includes the following steps:

[0117] S1. Melting and casting and online processing: Pure aluminum ingots are put into a melting furnace and heated to 730°C to melt. Alloy raw materials are then added into the melting furnace according to the weight of the components. After stirring, refining, degassing, filtering and casting, aluminum alloy ingots are obtained.

[0118] S2. Three-stage ingot homogenization treatment: The ingot undergoes a three-stage heating and staged room temperature resting homogenization treatment, specifically as follows:

[0119] (1) First stage: Heat to 310℃ at 110℃ / h, hold for 5 hours, then remove from the furnace and let stand at room temperature for 9 hours. In this stage, the lower temperature and longer holding time can allow solute atoms in the ingot to diffuse slowly, eliminate some casting stress, and prepare for subsequent grain refinement and homogenization treatment.

[0120] (2) Second stage: The temperature is raised to 430℃ at 140℃ / h, and after holding at the temperature for 5 hours, it is taken out of the furnace and left at room temperature for 9 hours. The diffusion rate of solute atoms is accelerated, the grain boundary migration and recrystallization process can be fully carried out, the grains are further refined and homogenized, and at the same time, some coarse second phase particles begin to dissolve, further improving the uniformity of the alloy structure.

[0121] (3) Third stage: Heat to 530℃ at 160℃ / h, hold for 7 hours, then slowly cool to 210℃ at a rate of 90℃ / h, and air cool to room temperature after removal from the furnace. During the cooling process, avoid the ingot being subjected to violent airflow impact to generate new stress, and ensure the stability and uniformity of the grains. Air cooling can quickly cool the ingot to room temperature, ensuring the microstructure after homogenization treatment.

[0122] S3. Extrusion Molding and Online Solution Aging: The homogenized ingot is heated to 400℃ and extruded at a speed of 0.9 m / min to produce a 90 mm diameter bar. The extruded bar undergoes online solution treatment at an inlet temperature of 360℃ and an outlet temperature of 550℃ for 9 minutes. After solution treatment, the bar is spray-quenched and then aged at 175℃ for 8 hours.

[0123] Comparative Example 2: The components and their weight percentages in the aluminum alloy are as follows:

[0124] The Si content is 0.95%;

[0125] The Mg content is 1.0%;

[0126] The Cu content is 0.3%;

[0127] The Mn content is 0.25%;

[0128] The Zr content is 0.12%;

[0129] The Ti content is 0.06%;

[0130] The Fe content is 0.06%;

[0131] The Cr content is 0.06%;

[0132] The total content of other individual impurity elements is ≤0.03%, with the balance being Al;

[0133] A method for preparing 6110A aluminum alloy bars for automotive forging includes the following steps:

[0134] S1. Melting and casting and online processing: Pure aluminum ingots are put into the melting furnace and heated to 730℃ to melt. The furnace feed port is divided into a 9-grid pattern. Each alloy raw material is divided into 9 parts according to the weight of the components and mixed. The parts are put into the melting furnace at the corresponding 9-grid positions. After stirring, refining, degassing, filtering and casting, aluminum alloy ingots are obtained.

[0135] S2. Homogenization treatment of ingots: The ingots are homogenized by heating them to 530°C, holding them at that temperature for 7 hours, and then air-cooling them to room temperature after they are taken out of the furnace.

[0136] S3. Extrusion Molding and Online Solution Aging: The homogenized ingot is heated to 400℃ and extruded at a speed of 0.9 m / min to produce a 90 mm diameter bar. The extruded bar undergoes online solution treatment at an inlet temperature of 360℃ and an outlet temperature of 550℃ for 9 minutes. After solution treatment, the bar is spray-quenched and then aged at 175℃ for 8 hours.

[0137] Comparative Example 3: The components and their weight percentages in the aluminum alloy are as follows:

[0138] The Si content is 0.95%;

[0139] The Mg content is 1.0%;

[0140] The Cu content is 0.3%;

[0141] The Mn content is 0.25%;

[0142] The Zr content is 0.12%;

[0143] The Ti content is 0.06%;

[0144] The Fe content is 0.06%;

[0145] The Cr content is 0.06%;

[0146] The total content of other individual impurity elements is ≤0.03%, with the balance being Al;

[0147] A method for preparing 6110A aluminum alloy bars for automotive forging includes the following steps:

[0148] S1. Melting and casting and online processing: Pure aluminum ingots are put into the melting furnace and heated to 730℃ to melt. The furnace feed port is divided into a 9-grid pattern. Each alloy raw material is divided into 9 parts according to the weight of the components and mixed. The parts are put into the melting furnace at the corresponding 9-grid positions. After stirring, refining, degassing, filtering and casting, aluminum alloy ingots are obtained.

[0149] S2. Three-stage ingot homogenization treatment: The ingot undergoes a three-stage heating and staged room temperature resting homogenization treatment, specifically as follows:

[0150] (1) First stage: Heat to 310℃ at 110℃ / h, hold for 5 hours, then remove from the furnace and let stand at room temperature for 9 hours. In this stage, the lower temperature and longer holding time can allow solute atoms in the ingot to diffuse slowly, eliminate some casting stress, and prepare for subsequent grain refinement and homogenization treatment.

[0151] (2) Second stage: The temperature is raised to 430℃ at 140℃ / h, and after holding at the temperature for 5 hours, it is taken out of the furnace and left at room temperature for 9 hours. The diffusion rate of solute atoms is accelerated, the grain boundary migration and recrystallization process can be fully carried out, the grains are further refined and homogenized, and at the same time, some coarse second phase particles begin to dissolve, further improving the uniformity of the alloy structure.

[0152] (3) Third stage: Heat to 530℃ at 160℃ / h, hold for 7 hours, then slowly cool to 210℃ at a rate of 90℃ / h, and air cool to room temperature after removal from the furnace. During the cooling process, avoid the ingot being subjected to violent airflow impact to generate new stress, and ensure the stability and uniformity of the grains. Air cooling can quickly cool the ingot to room temperature, ensuring the microstructure after homogenization treatment.

[0153] S3. Extrusion forming and solution aging: The homogenized ingot is heated to 400℃ and extruded at a speed of 0.9m / min. The diameter of the extruded bar is 90mm. The extruded bar is sprayed and quenched, and then subjected to offline solution treatment at a temperature of 530℃ for 2 hours. After cooling to room temperature in the furnace, it is then aged at 175℃ for 8 hours.

[0154] The mechanical property testing methods for the above embodiments and comparative examples were in accordance with GB / T228.1-2010 "Metallic materials - Tensile testing - Part 1: Test at room temperature", and the testing equipment was an AG-X 100KN electronic universal testing machine.

[0155] The standard test method for grain size and coarse grain layer thickness is GB / T3246.1-2024 "Methods for Inspection of Microstructure of Wrought Aluminum and Aluminum Alloy Products" Part 1: Microstructure Inspection Method, and the test equipment is AXIO universal research-grade inverted material microscope.

[0156] Table 1. Performance test results of aluminum alloy bars in Examples 1-3 and Comparative Examples 1-3

[0157]

[0158] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for preparing 6110A aluminum alloy bars for automotive forging, characterized in that, The components and their weight percentages in the aluminum alloy rod are as follows: The Si content is 0.75%-1.05%; The Mg content is 0.85%-1.15%; The Cu content is 0.25%-0.45%; The Mn content is 0.15%-0.35%; The Zr content is 0.08%-0.18%; The Ti content is 0.04%-0.08%; The Fe content is ≤0.08%; The Cr content is ≤0.08%; The total content of other individual impurity elements is ≤0.03%, with the balance being Al; The preparation method of the 6110A aluminum alloy bar for automotive forging includes: S1. Melting and casting and online processing: Pure aluminum ingots are put into a melting furnace and heated to 720-740℃ to melt. Then, alloy raw materials are put into the melting furnace and stirred, refined, degassed, filtered and cast to obtain aluminum alloy ingots. S2. Three-stage ingot homogenization treatment: The ingot is subjected to three-stage heating and staged room temperature resting homogenization treatment. S3. Extrusion forming and online solution aging: The homogenized ingot is heated to 390-410℃ for extrusion. The extruded bar is subjected to online solution treatment, followed by quenching, and then aging treatment.

2. The method for preparing 6110A aluminum alloy bars for automotive forging according to claim 1, characterized in that, In step S1, the charging port of the smelting furnace is divided into a 9-grid pattern, and each alloy raw material is divided into 9 equal parts according to the weight of the components and mixed, and then fed into the smelting furnace at the corresponding 9-grid positions.

3. The method for preparing 6110A aluminum alloy bars for automotive forging according to claim 1, characterized in that, In step S2, the three-stage ingot homogenization treatment is specifically as follows: first, the temperature is raised to 300-320℃ at 100-120℃ / h and held for 4-6 hours, then removed from the furnace and left at room temperature for 8-10 hours; then, the temperature is raised to 420-440℃ at 130-150℃ / h and held for 4-6 hours, then removed from the furnace and left at room temperature for 8-10 hours; finally, the temperature is raised to 520-540℃ at 150-170℃ / h and held for 6-8 hours, then slowly cooled to 200-220℃ at a rate of 80-100℃ / h and then air-cooled to room temperature.

4. The method for preparing 6110A aluminum alloy bars for automotive forging according to claim 1, characterized in that, In step S3, the extruded bar is fed into an online solution furnace for solution treatment. The temperature of the bar at the inlet of the solution furnace is controlled at 350-370℃, and the temperature at the outlet of the solution furnace is controlled at 540-560℃. The solution treatment time is 8-10 minutes.

5. The method for preparing 6110A aluminum alloy bars for automotive forging according to claim 4, characterized in that, The bar stock is solution treated and then spray-quenched, followed by aging treatment at 175℃ for 8 hours.

6. The method for preparing 6110A aluminum alloy bars for automotive forging according to claim 1, characterized in that, In step S3, the extrusion speed is 0.8-1 m / min.

7. The method for preparing 6110A aluminum alloy bars for automotive forging according to claim 1, characterized in that, In step S3, the diameter of the rod is 80-100mm.

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