6-series aluminum alloy and manufacturing method thereof

Abstract

The invention discloses a 6-series aluminum alloy and a manufacturing method thereof, and relates to the technical field of aluminum alloy materials. The 6-series aluminum alloy comprises the following components in percentage by mass: 0.65%-0.72% of Si, 1.02%-1.1% of Mg, 0.15%-0.2% of Mn, 0.05%-0.1% of Cr, 0.05%-0.1% of Cu, 0.1%-0.2% of Zr, 0.2%-0.4% of Ce, 0.1%-0.15% of La, 0.05%-0.1% of Fe, less than or equal to 0.05% of Ti and the balance of Al. The 6-series aluminum alloy disclosed by the invention has high strength and excellent corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy materials, and in particular to a 6 series aluminum alloy and a manufacturing method thereof. Background Art

[0002] 6 series aluminum alloy is a commonly used aluminum alloy material with the characteristics of light weight, medium strength, good plasticity and excellent processing performance. In recent years, with the popularization of automobile lightweight and energy-saving and emission reduction concepts, 6 series aluminum alloy has been more and more widely used in the automotive industry. It is mainly used to manufacture automobile body panels, frames and engine parts. However, the strength of 6 series aluminum alloy is not high, and it is difficult to meet the high strength requirements of automobiles when driving at high speeds. In addition, the corrosion resistance of 6 series aluminum alloy is general. When a car is driven at high speed in a humid environment, there is a greater risk of corrosion to the aluminum alloy body or parts, which leads to performance degradation or even failure. Therefore, in order to improve safety and durability, it is necessary to develop 6 series aluminum alloys with both high strength and excellent corrosion resistance. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a 6 series aluminum alloy and a manufacturing method thereof.

[0004] The invention provides a 6 series aluminum alloy, comprising the following components in percentage by mass: Si 0.65% to 0.72%, Mg 1.02% to 1.1%, Mn 0.15% to 0.2%, Cr 0.05% to 0.1%, Cu 0.05% to 0.1%, Zr 0.1% to 0.2%, Ce 0.2% to 0.4%, La 0.1% to 0.15%, Fe 0.05% to 0.1%, Ti≤0.05%, and the balance being Al.

[0005] Preferably, in the composition of the 6 series aluminum alloy, the mass ratio of Mg to Si is 1.58 to 1.66:1.

[0006] Preferably, the 6 series aluminum alloy includes the following components in mass percentage: Si 0.67%, Mg 1.08%, Mn 0.18%, Cr 0.06%, Cu 0.07%, Zr 0.12%, Ce 0.24%, La 0.14%, Fe 0.08%, Ti≤0.05%, and the balance is Al.

[0007] The present invention also discloses a method for manufacturing the 6 series aluminum alloy, comprising the following steps:

[0008] S1. Raw materials are prepared according to the composition and mass percentage of the aluminum alloy, added into a smelting furnace, heated to 725-740° C. for melting, then cooled to 705-715° C., subjected to ultrasonic treatment, refined, degassed and deslagging, cooled to 690-700° C., subjected to ultrasonic treatment, cast to obtain an ingot, and cooled;

[0009] S2, subjecting the ingot obtained in S1 to a two-stage homogenization treatment and cooling;

[0010] S3, hot extruding the ingot treated in S2, performing artificial aging treatment after cooling, and cooling to obtain the 6 series aluminum alloy.

[0011] Preferably, in S1, the power of the ultrasonic treatment is 200-500 W, and the time is 2-5 min.

[0012] Preferably, in S2, the step of double-stage homogenization treatment includes: firstly performing a first-stage homogenization treatment by keeping the temperature at 515-525°C for 8-10 hours, and then heating the temperature to 535-550°C and keeping the temperature for 20-24 hours for a second-stage homogenization treatment.

[0013] Preferably, in S3, the temperature of hot extrusion molding is 490-520° C., and the extrusion speed is 6-8 mm / s.

[0014] Preferably, in S3, the temperature of the artificial aging treatment is 170-190° C., and the time is 6-8 hours.

[0015] The beneficial effects of the present invention are as follows:

[0016] In the 6 series aluminum alloy formula of the present invention, a large amount of Mg2Si reinforcing phase can be formed in the aluminum alloy by controlling the contents of Mg and Si, and the mass ratio of Mg / Si. At the same time, due to a slight excess of Si, it can form Al(MnCrFe)Si phase and Al(MnFe)Si phase with Mn, Cr and Fe, which can not only improve the mechanical properties and corrosion resistance, but also consume Fe in the aluminum alloy to avoid the presence of Fe causing the solubility of the Mg2Si phase to decrease; appropriate amounts of Zr, Ce and La can promote grain refinement, enhance the mechanical strength of the aluminum alloy, and improve the corrosion resistance of the aluminum alloy; in the manufacturing method, by performing appropriate ultrasonic treatment before melt casting, the uniformity of the alloy structure can be improved, the solid solution effect of the Mg2Si reinforcing phase in the matrix can be improved, thereby improving the mechanical strength and intergranular corrosion resistance of the aluminum alloy; by performing appropriate two-stage homogenization treatment, the solid solution effect of the Mg2Si reinforcing phase in the matrix can be further improved, and the mechanical strength and intergranular corrosion resistance of the aluminum alloy can be improved. In summary, the present invention optimizes the formula and manufacturing process of the 6-series aluminum alloy, so that the 6-series aluminum alloy obtained has high strength and excellent corrosion resistance, and is an aluminum alloy material for automobiles with excellent performance. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below through specific embodiments.

[0018] Example 1

[0019] A 6 series aluminum alloy comprises the following components in percentage by mass: 0.65% Si, 1.07% Mg, 0.15% Mn, 0.05% Cr, 0.05% Cu, 0.1% Zr, 0.2% Ce, 0.1% La, 0.05% Fe, 0.05% Ti, and the balance is Al.

[0020] The manufacturing method of the above 6 series aluminum alloy comprises the following steps:

[0021] S1. Raw materials are prepared according to the composition and mass percentage of the aluminum alloy, added into a smelting furnace, heated to 725° C. and melted, then the melt is cooled to 705° C., ultrasonically treated for 2 min at a power of 200 W, refined, degassed and deslagging, then cooled to 690° C., ultrasonically treated for 2 min at a power of 200 W, cast to obtain an ingot, and air-cooled;

[0022] S2, the ingot obtained in S1 is firstly kept at 515°C for 8 hours for the first stage homogenization treatment, then the temperature is raised to 535°C, kept for 20 hours for the second stage homogenization treatment, and then air-cooled;

[0023] S3. The ingot treated in S2 is hot extruded at 490°C with an extrusion speed of 6 mm / s; then water-cooled, artificially aged at 170°C for 6 h, and air-cooled to obtain.

[0024] Example 2

[0025] A 6 series aluminum alloy comprises the following components in percentage by mass: 0.69% Si, 1.1% Mg, 0.2% Mn, 0.1% Cr, 0.1% Cu, 0.2% Zr, 0.4% Ce, 0.15% La, 0.1% Fe, 0.03% Ti, and the balance is Al.

[0026] The manufacturing method of the above 6 series aluminum alloy comprises the following steps:

[0027] S1. Raw materials are prepared according to the composition and mass percentage of the aluminum alloy, added into a smelting furnace, heated to 740° C. and melted, then the melt is cooled to 715° C., subjected to ultrasonic treatment at a power of 500 W for 5 min, refined, degassed and deslagging, then cooled to 700° C., subjected to ultrasonic treatment at a power of 500 W for 5 min, cast to obtain an ingot, and air-cooled;

[0028] S2, the ingot obtained in S1 is firstly kept at 525°C for 10 hours for the first stage homogenization treatment, then the temperature is raised to 550°C, kept at this temperature for 24 hours for the second stage homogenization treatment, and then air-cooled;

[0029] S3. The ingot treated in S2 is hot extruded at 520°C with an extrusion speed of 8 mm / s; then water-cooled, artificially aged at 190°C for 8 h, and air-cooled to obtain.

[0030] Example 3

[0031] A 6 series aluminum alloy comprises the following components in percentage by mass: 0.67% Si, 1.08% Mg, 0.18% Mn, 0.06% Cr, 0.07% Cu, 0.12% Zr, 0.24% Ce, 0.14% La, 0.08% Fe, 0.05% Ti, and the balance is Al.

[0032] The manufacturing method of the above 6 series aluminum alloy comprises the following steps:

[0033] S1. Raw materials are prepared according to the composition and mass percentage of the aluminum alloy, added into a smelting furnace, heated to 730° C. and melted, then the melt is cooled to 710° C., subjected to ultrasonic treatment at a power of 300 W for 3 min, refined, degassed and deslagging, then cooled to 695° C., subjected to ultrasonic treatment at a power of 300 W for 3 min, cast to obtain an ingot, and air-cooled;

[0034] S2, the ingot obtained in S1 is firstly kept at 520°C for 9 hours for the first stage homogenization treatment, then the temperature is raised to 540°C, kept for 24 hours for the second stage homogenization treatment, and then air-cooled;

[0035] S3. The ingot treated in S2 is hot extruded at 500°C with an extrusion speed of 8 mm / s; then water-cooled, artificially aged at 180°C for 6 hours, and air-cooled to obtain.

[0036] Example 4

[0037] A 6 series aluminum alloy comprises the following components in percentage by mass: 0.65% Si, 1.1% Mg, 0.15% Mn, 0.05% Cr, 0.05% Cu, 0.1% Zr, 0.2% Ce, 0.1% La, 0.05% Fe, 0.05% Ti, and the balance is Al.

[0038] The manufacturing method of the above 6 series aluminum alloy is the same as that of Example 1.

[0039] Example 5

[0040] A 6 series aluminum alloy comprises the following components in percentage by mass: 0.72% Si, 1.02% Mg, 0.15% Mn, 0.05% Cr, 0.05% Cu, 0.1% Zr, 0.2% Ce, 0.1% La, 0.05% Fe, 0.05% Ti, and the balance is Al.

[0041] The manufacturing method of the above 6 series aluminum alloy is the same as that of Example 1.

[0042] Comparative Example 1

[0043] A 6 series aluminum alloy comprises the following components in percentage by mass: 0.65% Si, 1.07% Mg, 0.15% Mn, 0.05% Cr, 0.05% Cu, 0.1% Zr, 0.2% Ce, 0.1% La, 0.05% Fe, 0.05% Ti, and the balance is Al.

[0044] The manufacturing method of the above 6 series aluminum alloy comprises the following steps:

[0045] S1. Raw materials are prepared according to the composition and mass percentage of the aluminum alloy, added into a smelting furnace, heated to 725° C. for melting, then cooled to 705° C., refined, degassed and deslagged, and then cooled to 690° C., cast to obtain an ingot, and air-cooled;

[0046] S2, the ingot obtained in S1 is firstly kept at 515°C for 8 hours for the first stage homogenization treatment, then the temperature is raised to 535°C, kept for 20 hours for the second stage homogenization treatment, and then air-cooled;

[0047] S3. The ingot treated in S2 is hot extruded at 490°C with an extrusion speed of 6 mm / s; then water-cooled, artificially aged at 170°C for 6 h, and air-cooled to obtain.

[0048] Comparative Example 2

[0049] A 6 series aluminum alloy comprises the following components in percentage by mass: 0.65% Si, 1.07% Mg, 0.15% Mn, 0.05% Cr, 0.05% Cu, 0.1% Zr, 0.2% Ce, 0.1% La, 0.05% Fe, 0.05% Ti, and the balance is Al.

[0050] The manufacturing method of the above 6 series aluminum alloy comprises the following steps:

[0051] S1. Raw materials are prepared according to the composition and mass percentage of the aluminum alloy, added into a smelting furnace, heated to 725° C. and melted, then the melt is cooled to 705° C., ultrasonically treated for 2 min at a power of 200 W, refined, degassed and deslagging, then cooled to 690° C., ultrasonically treated for 2 min at a power of 200 W, cast to obtain an ingot, and air-cooled;

[0052] S2, the ingot obtained in S1 is kept at 535°C for 24 hours for homogenization treatment, and then cooled by air cooling;

[0053] S3. The ingot treated in S2 is hot extruded at 490°C with an extrusion speed of 6 mm / s; then water-cooled, artificially aged at 170°C for 6 h, and air-cooled to obtain.

[0054] Test example

[0055] The aluminum alloys of Examples 1 to 5 and Comparative Examples 1 to 2 were subjected to performance tests, wherein the mechanical properties test was performed in accordance with GB / T228.1-2010; the intergranular corrosion test was performed by corroding the sample in a mixed solution of sodium chloride and hydrochloric acid at 35±2°C for 48 hours, and measuring the maximum corrosion depth with a metallographic microscope. The sodium chloride and hydrochloric acid solution was prepared by placing 30±0.1g of sodium chloride in a beaker, adding 1L of distilled water and mixing evenly, and then adding 10mL of hydrochloric acid (ρ1.19g / mL) and mixing evenly. The test results are shown in Table 1:

[0056] Table 1

[0057]

[0058]

[0059] It can be seen from Table 1 that the 6 series aluminum alloy manufactured by the present invention has both high strength and toughness and excellent corrosion resistance.

[0060] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A 6 series aluminum alloy, characterized in that: The 6 series aluminum alloy includes the following components in mass percentage: Si 0.65% to 0.72%, Mg 1.02% to 1.1%, Mn 0.15% to 0.2%, Cr 0.05% to 0.1%, Cu 0.05% to 0.1%, Zr 0.1% to 0.2%, Ce 0.2% to 0.4%, La 0.1% to 0.15%, Fe 0.05% to 0.1%, Ti≤0.05%, and the balance is Al.

2. The 6 series aluminum alloy according to claim 1, characterized in that: In the composition of the 6 series aluminum alloy, the mass ratio of Mg to Si is 1.58 to 1.66:

1.

3. The 6 series aluminum alloy according to claim 1, characterized in that: The 6 series aluminum alloy includes the following components in mass percentage: Si 0.67%, Mg 1.08%, Mn 0.18%, Cr 0.06%, Cu 0.07%, Zr 0.12%, Ce 0.24%, La 0.14%, Fe 0.08%, Ti≤0.05%, and the balance is Al.

4. A method for manufacturing a 6 series aluminum alloy as claimed in claim 1, characterized in that: The steps include: S1. Raw materials are prepared according to the composition and mass percentage of the aluminum alloy, added into a smelting furnace, heated to 725-740° C. for melting, then cooled to 705-715° C., subjected to ultrasonic treatment, refined, degassed and deslagging, cooled to 690-700° C., subjected to ultrasonic treatment, cast to obtain an ingot, and cooled; S2, subjecting the ingot obtained in S1 to a two-stage homogenization treatment and cooling; S3, hot extruding the ingot after the S2 treatment, performing artificial aging treatment after cooling, and cooling to obtain the 6 series aluminum alloy.

5. The method for producing a 6 series aluminum alloy according to claim 4, characterized in that: In S1, the power of ultrasonic treatment is 200-500 W, and the time is 2-5 min.

6. The method for producing a 6 series aluminum alloy according to claim 1, characterized in that: In S2, the steps of double-stage homogenization treatment include: firstly, keeping the temperature at 515-525°C for 8-10 hours for the first stage homogenization treatment, and then raising the temperature to 535-550°C and keeping the temperature for 20-24 hours for the second stage homogenization treatment.

7. The method for producing a 6 series aluminum alloy according to claim 1, characterized in that: In S3, the temperature of hot extrusion molding is 490-520°C, and the extrusion speed is 6-8 mm / s.

8. The method for producing a 6 series aluminum alloy according to claim 1, characterized in that: In S3, the temperature of artificial aging treatment is 170-190°C and the time is 6-8h.

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