6xxx aluminum alloy wire rod and application thereof

Abstract

The invention belongs to the technical field of aluminum alloy, and particularly relates to a 6xxx aluminum alloy wire rod and application thereof. The 6xxx aluminum alloy comprises the following components in percentage by mass: more than 1.0% and less than 1.1% of Mg; 0.8% < = Si < = 1.3%; cu is more than 0.5% and less than 0.65%; mn is more than 0.40% and less than 0.5%; zr is greater than or equal to 0.08% and less than 0.1%; 0.1% < = Fe < 0.15%; zn < = 0.005%; cr is more than 0.15% and less than or equal to 0.2%; 0.06% < = Ti < = 0.1%; the total mass content of the inevitable impurities is less than or equal to 0.5%. According to the 6xxx aluminum alloy, the component content is optimized, meanwhile, the wire rod is prepared through the hot continuous rolling technology, the O-state elongation of the 6xxx aluminum alloy is larger than or equal to 30%, and the cold heading deformation is larger than or equal to 85%. After T6 heat treatment, the yield strength of the prepared 6xxx aluminum alloy wire rod is larger than or equal to 410 MPa and the tensile strength of the 6xxx aluminum alloy wire rod is larger than or equal to 450 MPa at the room temperature, the yield strength of the 6xxx aluminum alloy wire rod is larger than or equal to 355 MPa and the tensile strength of the 6xxx aluminum alloy wire rod is larger than or equal to 385 MPa at the temperature of 150 DEG C in the T6 state, and the 6xxx aluminum alloy wire rod can meet the application requirements in complex environments with large temperature differences.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloys, and in particular relates to a 6xxx aluminum alloy wire rod and applications thereof. Background Art

[0002] The demand for automotive fasteners accounts for about 23% of the total sales of the entire fastener industry, the highest share in the industry. A passenger car has about 5,000 fasteners, and the automotive fastener market exceeded 2.85 million tons in 2023. 6xxx aluminum alloy is widely used in the field of automotive fasteners due to its low density, moderate strength, easy processing and good corrosion resistance. However, due to the complex use environment and large temperature changes of fasteners, the requirements for 6xxx aluminum alloy and processing technology are relatively high. At present, domestic high-end fasteners with high strength, high toughness and heat resistance for automobiles still rely on imports.

[0003] In addition, domestic fastener wire rods are generally produced by extrusion-drawing and continuous casting and rolling-drawing. The alloy performance of the extrusion-drawing method is stable but the coil weight is small. Large coil weight has more welded joints, and the production process is long and the cost is high. The continuous casting and rolling-drawing method has large production capacity and high efficiency, but it is difficult to produce high-alloy products, and the performance fluctuates greatly and the forgeability is poor.

[0004] At present, there are many studies related to aluminum alloys for automotive fasteners, but there are some shortcomings. CN106834822A discloses a high-strength 6-series aluminum alloy for automotive fasteners and a preparation method thereof, and its tensile strength can reach 530MPa, but more Ag and Er elements are added to the material, and the manufacturing cost is greatly increased, which is difficult to meet the demand of the automotive field. CN114892050A provides a high-Cu 6-series aluminum alloy, and its yield strength is 370-410MPa, but the elongation is only 10-15%, which is difficult to meet the demand of high plasticity for cold heading deformation. CN112853169A provides a high-strength 6-series aluminum alloy bolt and a manufacturing method thereof, although the material has a high tensile strength, the yield strength is relatively low (T6 state yield strength <400MPa), which cannot simultaneously meet the requirements of high strength and high toughness and high temperature resistance, and the elongation and cold heading deformation of the material are not mentioned, and the specific preparation process of the wire rod is not involved. CN103339276A provides aluminum alloy wire for bolts, bolts and manufacturing methods thereof. Although the material has high tensile strength, its yield strength is relatively low (T6 state yield strength <390MPa), which cannot simultaneously meet the requirements of high strength and high toughness, and cannot meet the performance requirements of high temperature resistance. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a 6xxx aluminum alloy wire rod and its application, and the present invention specifically includes the following contents:

[0006] A 6xxx aluminum alloy wire rod, wherein the composition and mass percentage of the 6xxx aluminum alloy are as follows:

[0007] 1.0%<Mg<1.1%;

[0008] 0.8%≤Si≤1.3%;

[0009] 0.5%<Cu<0.65%;

[0010] 0.40%<Mn<0.5%;

[0011] 0.08%≤Zr<0.1%;

[0012] 0.1%≤Fe<0.15%;

[0013] Zn≤0.005%;

[0014] 0.15%<Cr≤0.2%;

[0015] 0.06%≤Ti≤0.1%;

[0016] The total mass content of inevitable impurities is ≤0.5%, the balance is Al; where (Mg+Si) / Cu=3.33-3.83;

[0017] The preparation method of the 6xxx aluminum alloy wire rod comprises the following steps:

[0018] S1, ingot casting: alloy ingots are prepared by semi-continuous casting;

[0019] S2, homogenization annealing treatment: heat the alloy ingot to 380-420℃ and keep it for 2-10h, then heat it to 560-575℃ at a rate of 20-30℃ / h and keep it for 6-12h;

[0020] S3, rolling: the annealed alloy ingot is hot-rough rolled at 520-550℃ to The bars are then hot rolled at 420-450℃ Rods;

[0021] S4, annealing: The rod is kept at 380-420℃ for 1-1.5h;

[0022] S5, drawing: the annealed Rod pull to Wire poles;

[0023] S6, finished product annealing: The wire rod is kept at 360-420℃ for 1-2h.

[0024] Preferably, the 6xxx aluminum alloy in O state has an average grain size of ≤40 μm, a diameter of Mg2Si of ≤5 μm, an elongation of ≥30%, and a cold heading deformation of ≥85%.

[0025] Preferably, after the T6 heat treatment, the 6xxx aluminum alloy wire rod has a yield strength of ≥410MPa and a tensile strength of ≥450MPa at room temperature, and a yield strength of ≥355MPa and a tensile strength of ≥385MPa at 150°C.

[0026] Preferably, the process of T6 heat treatment of the 6xxx aluminum alloy wire rod is: keeping at 555-565°C for 1-2h, then water quenching, and finally keeping at 170-185°C for 6-10h.

[0027] A fastener prepared using the 6xxx aluminum alloy wire rod.

[0028] An application of the fastener in an automobile.

[0029] Beneficial effects of the present invention:

[0030] The present invention optimizes the content of components such as Mg, Cu, Fe, Cr, Ti, and adjusts the content of Zr. At the same time, the hot rolling process is used to prepare the wire rod, and the preparation process is improved and optimized in combination with the characteristics of the material components, thereby reducing the volume fraction of coarse intermetallic compounds, optimizing and refining the grains in a coordinated annealing process, and improving the strength and cold heading performance of the material. The 6xxx aluminum alloy described in the present invention has an average grain size of ≤40μm in the O state, wherein the diameter of Mg2Si is ≤5μm, the elongation is ≥30%, and the cold heading deformation is ≥85%.

[0031] In addition, the present invention adjusts the content of Mn and further limits the content of Zn. At the same time, combined with the adjustment of the homogenization annealing process, the precipitation of A3Zr and AlFeMnSi particles is effectively controlled, and the heat resistance of the alloy is improved. After the T6 heat treatment, the 6xxx aluminum alloy wire rod prepared by the present invention has a yield strength of ≥410MPa and a tensile strength of ≥450MPa at room temperature. It has the characteristics of high strength and high toughness, and can fully meet the performance requirements of automotive fasteners. In addition, the 6xxx aluminum alloy wire rod of the present invention also has the characteristics of high temperature resistance. The yield strength of the T6 state at 150°C is ≥355MPa and the tensile strength is ≥385MPa, which can meet the application requirements in complex environments with large temperature differences. DETAILED DESCRIPTION

[0032] A 6xxx aluminum alloy wire rod, wherein the composition and mass percentage of the 6xxx aluminum alloy are as follows:

[0033] 1.0%<Mg<1.1%;0.8%≤Si≤1.3%;0.5%<Cu<0.65%;0.40%<Mn<0.5%;0.08%≤Zr<0.1%;0.1%≤Fe<0.15%;Zn≤0.005%;0.15%<Cr≤0.2%;0.06%≤Ti≤0.1%;Total mass content of inevitable impurities≤0.5%, the balance is Al, and (Mg+Si) / Cu=3.33-3.83

[0034] The preparation method of the 6xxx aluminum alloy wire rod comprises the following steps:

[0035] S1, ingot casting: alloy ingots are prepared by semi-continuous casting;

[0036] S2, homogenization annealing treatment: heat the alloy ingot to 380-420℃ and keep it for 2-10h, then heat it to 560-575℃ at a rate of 20-30℃ / h and keep it for 6-12h;

[0037] S3, rolling: the annealed alloy ingot is hot-rough rolled at 520-550℃ to The bars are then hot rolled at 420-450℃ Rods;

[0038] S4, annealing: The rod is kept at 380-420℃ for 1-1.5h;

[0039] S5, drawing: the annealed Rod pull to Wire poles;

[0040] S6, finished product annealing: The wire rod is kept at 360-420℃ for 1-2h.

[0041] The 6xxx aluminum alloy O state prepared by the above composition and method has the following characteristics: average grain size ≤40μm, diameter of Mg2Si ≤5μm, elongation ≥30%, and cold heading deformation ≥85%.

[0042] After T6 heat treatment (T6 state), the 6xxx aluminum alloy wire rod prepared by the above composition and method has a yield strength of ≥410MPa and a tensile strength of ≥450MPa at room temperature, and a yield strength of ≥355MPa and a tensile strength of ≥385MPa at 150°C. The T6 heat treatment process of the 6xxx aluminum alloy wire rod is: heat preservation at 555-565°C for 1-2h, then water quenching, and finally heat preservation at 170-185°C for 6-10h.

[0043] The present invention is described in detail below in conjunction with specific embodiments. The embodiments shown below do not limit the invention content described in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary as solutions to the invention described in the claims.

[0044] Example 1

[0045] The aluminum alloy components, in mass percentage, are: Mg 1.0wt.%, Si 0.8wt.%, Mn 0.4wt.%, Zr 0.08wt.%, Cu 0.52wt.%, Ti 0.1wt.%, Fe 0.14wt.%, Cr 0.2wt.%, and Zn 0.005wt.%.

[0046] The above alloy components are cast into The semi-continuous ingot was heated to 400℃ and kept at this temperature for 10h, then heated to 565℃ at a rate of 30℃ / h and kept at this temperature for 12h. The ingot after homogenization treatment was milled and heated to 520℃ and hot rolled to The bars are then hot rolled at 450°C After annealing at 420℃ / 1h, the bar is drawn to Wire rod. The finished product annealing system of wire rod is 420℃ / 1h.

[0047] The T6 heat treatment process of the wire rod is: 565℃, keep warm for 1h, water quench, and then keep warm at 175℃ for 10h.

[0048] Example 2

[0049] The aluminum alloy components, in mass percentage, are: Mg 1.08wt.%, Si 1.3wt.%, Mn 0.48wt.%, Zr0.095wt.%, Cu 0.64wt.%, Ti 0.06wt.%, Fe 0.1wt.%, Cr 0.155wt%, and Zn0.002wt.%.

[0050] The above alloy components are cast into The semi-continuous ingot was heated to 420℃ and kept at this temperature for 4h, then heated to 575℃ at a rate of 20℃ / h and kept at this temperature for 6h. The homogenized ingot was milled and heated to 550℃ and hot rolled to The bars are then hot rolled at 420°C. After annealing at 380℃ / 1h, the bar is drawn to Wire rod. The finished product annealing system of wire rod is 360℃ / 2h.

[0051] The T6 heat treatment process of the wire rod is: 555℃, keep warm for 2h, water quench, and then keep warm at 185℃ for 6h.

[0052] Example 3

[0053] The aluminum alloy components, in mass percentage, are: Mg 1.06wt.%, Si 0.9wt.%, Mn 0.45wt.%, Zr0.09wt.%, Cu 0.55wt.%, Ti 0.06wt.%, Fe 0.12wt.%, Cr 0.16wt.%, and Zn 0.003wt.%.

[0054] The above alloy components are cast into The semi-continuous ingot was heated to 380℃ and kept at this temperature for 8h, then heated to 570℃ at a rate of 25℃ / h and kept at this temperature for 10h. The ingot after homogenization treatment was milled and heated to 530℃ and hot rolled to The bars are then hot rolled at 430°C. After annealing at 400℃ / 1h, the bar is drawn to Wire rod. The finished product annealing system of wire rod is 400℃ / 2h.

[0055] The T6 heat treatment process of the wire rod is: 560℃, keep warm for 1h, water quench, and then keep warm at 175℃ for 8h.

[0056] Example 4

[0057] The aluminum alloy components, in mass percentage, are: Mg 1.07wt.%, Si 0.9wt.%, Mn 0.48wt.%, Zr0.09wt.%, Cu 0.59wt.%, Ti 0.1wt.%, Fe 0.13wt.%, Cr 0.17wt.%, and Zn 0.003wt.%.

[0058] The above alloy components are cast into The semi-continuous ingot was heated to 400℃ and kept at this temperature for 8h, then heated to 565℃ at a rate of 25℃ / h and kept at this temperature for 12h. The homogenized ingot was milled and heated to 542℃ and hot rolled to The bars are then hot rolled at 450°C After intermediate annealing at 380℃ / 1h, the bar is drawn to Wire rod. The finished product annealing system of wire rod is 380℃ / 1h.

[0059] The T6 heat treatment process of the wire rod is: 555℃, keep warm for 1h, water quench, and then keep warm at 180℃ for 6h.

[0060] Example 5

[0061] The aluminum alloy components, in mass percentage, are: Mg 1.06wt.%, Si 1.0wt.%, Mn 0.46wt.%, Zr0.09wt.%, Cu 0.6wt.%, Ti 0.08wt.%, Fe 0.14wt.%, Cr 0.17wt.%, and Zn 0.003wt.%.

[0062] The above alloy components are cast into The semi-continuous ingot was heated to 370℃ at a rate of 23℃ / h and kept at this temperature for 5h, then heated to 570℃ and kept at this temperature for 10h. The ingot after homogenization treatment was milled and heated to 540℃ and hot rolled to The bars are then hot rolled at 450°C After annealing at 400℃ / 1h, the bar is drawn to Wire rod. The finished product annealing system of wire rod is 400℃ / 2h.

[0063] The T6 heat treatment process of the wire rod is: 560℃, keep warm for 1h, water quench, and then keep warm at 175℃ for 8h.

[0064] Example 6

[0065] The aluminum alloy components, in mass percentage, are: Mg 1.03wt.%, Si 1.15wt.%, Mn 0.43wt.%, Zr 0.08wt.%, Cu 0.57wt.%, Ti 0.1wt.%, Fe 0.12wt.%, Cr 0.17wt.%, and Zn 0.002wt.%.

[0066] The above alloy components are cast into The semi-continuous ingot was heated to 320℃ at a rate of 25℃ / h and kept at this temperature for 6h, then heated to 570℃ and kept at this temperature for 10h. The ingot after homogenization treatment was milled and heated to 536℃ and hot rolled to The bars are then hot rolled at 410°C. After annealing at 380℃ / 1h, the bar is drawn to Wire rod. The finished product annealing system of wire rod is 400℃ / 2h.

[0067] The T6 heat treatment process of the wire rod is: 565℃, keep warm for 1h, water quench, and then keep warm at 175℃ for 8h.

[0068] Comparative Example 1

[0069] The aluminum alloy components are, by mass percentage, Mg 0.5wt.%, Si 0.8wt.%, Mn 0.12wt.%, Cr 0.03wt.%, Cu 0.25wt.%, Ti 0.25wt.%, Fe 0.4wt.%.

[0070] The same process as in the first embodiment is adopted.

[0071] Comparative Example 2

[0072] The ingredients are consistent with those in Example 1.

[0073] The above alloy components are cast into The semi-continuous ingot is heated to 500℃ and kept at this temperature for 20h. The ingot after homogenization treatment is milled and heated to 420℃ and hot rolled to The bars are then hot rolled at 400°C After intermediate annealing at 380℃ / 1h, the bar is drawn to Wire rod. The finished product annealing system of wire rod is 350℃ / 1h.

[0074] The T6 heat treatment process of the wire rod is: 540°C, heat preservation for 1 hour, water quenching, and then heat preservation for 8 hours at 175°C. Table 1 shows the performance and microstructure characteristics of the wire rod after annealing in the embodiment and the comparative example (tested according to the national standard GB / T 228.1-2010).

[0075] Table 1 Performance and microstructure characteristics of the wire rod after annealing of the finished product in the embodiment and the comparative example

[0076]

[0077]

[0078] Table 2 shows the mechanical properties of the T6 state materials in the embodiments and comparative examples after being kept at 150°C for 24 hours (tested according to the national standard GB / T 228.1-2010). The material of the present invention still has a higher strength (compared with the comparative example) after being subjected to high temperature for a long time in the T6 state, which fully demonstrates the high temperature resistance of the material of the present invention.

[0079] Table 2 Performance of materials in T6 state at room temperature and 150°C in the examples and comparative examples

[0080]

[0081] Since Comparative Example 1 contains a high Fe content, it is easy to crack during the cold heading process; and the Mg and Si contents are low, resulting in low mechanical properties of the material in the T6 state; and the low Mn and Zr contents result in low tensile properties of the material after being kept at 150°C for 24 hours; although the composition of Comparative Example 2 is consistent with that of Example 1, the homogenization temperature used in Comparative Example 2 is low, and there is no slow heating process, which is not conducive to the precipitation of dispersed particles that can control grain growth and the dissolution of coarse phases, resulting in poor subsequent elongation and poor high-temperature stability.

[0082] In summary, the present invention reasonably adjusts the content of each element in the aluminum alloy and the processing technology, so that the material has high strength, high plasticity (forming performance) and high-temperature mechanical stability.

[0083] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A 6xxx aluminum alloy wire pole, characterized in that: The composition and mass percentage of the 6xxx aluminum alloy are as follows: 1.0%<Mg<1.1%; 0.8%≤Si≤1.3%; 0.5%<Cu<0.65%; 0.40%<Mn<0.5%; 0.08％≤Zr＜0.1％； 0.1%≤Fe<0.15%; Zn≤0.005%; 0.15％＜Cr≤0.2％； 0.06%≤Ti≤0.1%; The total mass content of inevitable impurities is ≤0.5%, the balance is Al; where (Mg+Si) / Cu=3.33-3.83; Preparation method of the 6xxx aluminum alloy wire rod The following steps are involved: S1, ingot casting: alloy ingots are prepared by semi-continuous casting; S2, homogenization annealing treatment: heat the alloy ingot to 380-420℃ and keep it for 2-10h, then heat it to 560-575℃ at a rate of 20-30℃ / h and keep it for 6-12h; S3, rolling: hot rough rolling the annealed alloy ingot at 520-550°C to φ18-22 mm bars, and then hot finish rolling at 420-450°C to φ8-10.8 mm bars; S4, annealing: keeping the φ8-10.8 mm rod at 380-420° C. for 1-1.5 h; S5, drawing: drawing the annealed φ8-10.8mm bar to φ6-8mm wire rod; S6, finished product annealing: the φ6-8 mm wire rod is kept at 360-420° C. for 1-2 hours.

2. A 6xxx aluminum alloy wire rod according to claim 1, characterized in that: The average grain size of the 6xxx aluminum alloy in the O state is ≤40 μm, and the diameter of Mg2Si is ≤5 μm.

3. A 6xxx aluminum alloy wire rod according to claim 2, characterized in that: The 6xxx aluminum alloy has an O-state elongation of ≥30% and a cold heading deformation of ≥85%.

4. The 6xxx aluminum alloy wire rod according to any one of claims 1-3, characterized in that: After T6 heat treatment, the 6xxx aluminum alloy wire rod has a yield strength of ≥410MPa and a tensile strength of ≥450MPa at room temperature, and a yield strength of ≥355MPa and a tensile strength of ≥385MPa at 150°C.

5. A 6xxx aluminum alloy wire rod according to claim 4, characterized in that: The process of T6 heat treatment of the 6xxx aluminum alloy wire rod is: keeping at 555-565° C. for 1-2 hours, then water quenching, and finally keeping at 170-185° C. for 6-10 hours.

6. A fastener made from the 6xxx aluminum alloy wire rod of any one of claims 1-5.

7. Use of the fastener according to claim 6 in an automobile.

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