TW201819648A - High-strength and anti-corrosion aluminum-magnesium plate material which is obtained by performing hot rolling under a condition of controlling aluminum-magnesium alloy blank at a final rolling temperature of 250 to 300 DEG C and rolling/extending amount of 55 to 80% - Google Patents

Abstract

The present invention provides a method for manufacturing aluminum-magnesium plate material, which is obtained by performing a hot rolling under a condition in which an aluminum-magnesium alloy blank is controlled at a final rolling temperature of 250 to 300 DEG C and a rolling/extending amount of 55 to 80%. The aluminum-magnesium alloy is composed of: 0.09 to 0.14 wt% of niobium, 0.17 to 0.31 wt% of iron, 0.01 to 0.07 wt% of copper, 0.46 to 1.5 wt% of manganese, and 3.5 to 6.0 wt% of magnesium, 0.06 to 0.09 wt% of chromium, not more than 0.01 wt% of titanium, and residual amount of aluminum. In addition, this invention also provides a high-strength and anti-corrosion aluminum-magnesium plate material prepared by the manufacturing method.

Description

High-strength and corrosion-resistant aluminum-magnesium series plate and manufacturing method thereof

The invention relates to an aluminum-magnesium-based sheet material and a manufacturing method thereof, and particularly to a high-strength and corrosion-resistant aluminum-magnesium sheet material and a manufacturing method thereof.

Aluminum-magnesium alloys have the advantages of light weight, good strength, good formability, and aesthetics. Therefore, they are often used as materials for aircraft parts and ships, but in recent years, they have been developed in accordance with the energy-saving and lightweight development of the general transportation industry. , Aluminum alloy materials are also gradually applied to related parts of automobiles, locomotives and various vehicles.

The traditional aluminum-magnesium alloy sheet is generally produced by first homogenizing the aluminum-magnesium alloy blank (above 400 ° C / 2 hours + 500 ° C above / 8 hours), preheating (above 450 ° C / 1 hour), and then rolling. Hot rolling is performed at a temperature of 300 to 480 ° C, and then 20 to 50% cold rolling is applied to obtain an aluminum-magnesium alloy sheet. The aluminum-magnesium alloy sheet is finally annealed (annealing temperature: 220-245 ° C, holding temperature 2) ~ 5 hours), and cooled to room temperature within 3 hours to obtain the final finished aluminum-magnesium alloy plate. However, when the annealing temperature is lower than 200 ° C, the β phase (Mg ₂ Al ₃ ) of the aluminum-magnesium alloy will be easily precipitated at the grain boundary to form a corrosion-prone structure, and the corrosion propagation path will be provided, which will cause the aluminum-magnesium alloy to be used in the process. Prone to severe corrosion damage.

Therefore, an object of the present invention is to provide a method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium-based sheet material.

Therefore, the aluminum-magnesium-based sheet material manufacturing method of the present invention includes hot-rolling an aluminum-magnesium-based alloy blank at a finishing temperature of 250-300 ° C and a rolling reduction of 55-80%. Wherein, the composition of the aluminum-magnesium alloy includes: 0.09 to 0.14 wt% of silicon, 0.17 to 0.31 wt% of iron, 0.01 to 0.07 wt% of copper, 0.46 to 1.5 wt% of manganese, and 3.5 to 6.0 wt. % Magnesium, 0.06 ~ 0.09wt% chromium, no more than 0.01wt% titanium, and the remaining amount of aluminum.

In addition, another object of the present invention is to provide an aluminum-magnesium-based sheet material having high strength and corrosion resistance.

Therefore, the aluminum-magnesium-based sheet material of the present invention is produced by the aforementioned method for manufacturing an aluminum-magnesium-based sheet material.

The effect of the invention lies in that: by controlling the magnesium and manganese content of the aluminum-magnesium alloy blank, and by increasing the rolling amount and rolling temperature, not only can the strength of the aluminum-magnesium alloy plate obtained be improved, but also because The rolling amount can quickly reduce the temperature of the aluminum-magnesium alloy during the rolling process, and reduce the generation of easily corroded structures. Therefore, the corrosion resistance of the aluminum-magnesium alloy plate can also be effectively improved.

The method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium-based sheet material comprises rolling an aluminum-magnesium-based alloy blank at a rolling temperature between 250-300 ° C and a rolling amount controlled at 55-80%. Delayed.

In detail, the aluminum-magnesium-based sheet manufacturing method first prepares an aluminum-magnesium alloy blank containing a composition ratio as follows: 0.09 to 0.14 wt% silicon, 0.17 to 0.31 wt% iron, and 0.01 to 0.07 wt%. Copper, 0.46 to 1.5 wt% manganese, 3.5 to 6.0 wt% magnesium, 0.06 to 0.09 wt% chromium, no more than 0.01 wt% titanium, and aluminum in the remaining content. Next, the aluminum-magnesium alloy blank is homogenized and preheated, and then hot-rolled to obtain the aluminum-magnesium-based sheet material of the present invention. By adjusting the manganese (0.46 to 1.5 wt%) and magnesium (3.5 to 6.0 wt%) contents of the aluminum-magnesium alloy blank, the magnesium content is controlled to be between 3.5 to 6.0 wt%. Generally speaking, the higher the magnesium content is, the higher the overall mechanical strength is, but the disadvantage is that β phase (Mg ₂ Al ₃ ) is formed at the grain boundary. According to the experimental results, it can be obtained that its strength and corrosion characteristics are optimal. The content needs to be controlled between 3.5 ~ 6.0wt%. The present invention further controls the manganese content from 0.46 to 1.5 wt% to adjust the distribution of the precipitates, control the crystal size and softening characteristics, without impairing the corrosion resistance of the aluminum-magnesium alloy.

In addition, in conjunction with the control of the rolling process, the hot rolling temperature is controlled at 250 ~ 300 ° C, and the rolling amount is greatly increased to 55 ~ 80%. In addition to improving the strength of the rolled aluminum-magnesium alloy sheet, the aluminum-magnesium alloy can also be rapidly cooled during the rolling process, reducing the aluminum-magnesium alloy billet to stay in the temperature range that is prone to corrosion structures (100 ~ 200 ° C) to reduce the chance of continuous precipitation of the β phase (Mg ₂ Al ₃ ) of the magnesium-aluminum alloy at the grain boundaries. Therefore, compared with the aluminum-magnesium alloy plate prepared by the conventional process, the aluminum-magnesium system of the present invention The sheet manufacturing method can effectively reduce the occurrence of easily corrodible structures and improve the corrosion resistance of the finally produced aluminum-magnesium alloy sheet.

Preferably, the manganese content of the aluminum-magnesium alloy billet of the present invention is between 0.46 and 0.8 wt%, and the magnesium content is between 3.97 and 4.8 wt%; more preferably, the magnesium content is between 4.1 and 4.8 wt%. And preferably, the rolling amount is controlled at 60 to 80%, and more preferably, the rolling amount is controlled at 70 to 80%.

The following specific examples and comparative examples are used to describe in detail the manufacturing method of the aluminum-magnesium-based sheet material in this case.

Specific Example 1 First prepare an aluminum-magnesium alloy blank having a composition ratio as follows: 0.12 wt% silicon, 0.31 wt% iron, 0.06 wt% copper, 0.46 wt% manganese, 3.97 wt% magnesium, 0.08% by weight of chromium, 0.01% by weight of titanium, and the remaining content of aluminum. Next, the aluminum-magnesium alloy billet was homogenized, preheated, and then hot-rolled to obtain a test piece 1. Homogenization conditions: 400 ° C or higher for 2 hours + 500 ° C or higher for 8 hours Preheating conditions: 450 ° C or higher for 1 hour Hot rolling conditions: finish rolling temperature of 265 ° C and rolling reduction of 77%

Specific examples 2 to 8 The manufacturing methods of the specific examples 2 to 8 are similar to those of the specific example 1. The difference is that the aluminum-magnesium alloy blanks of the specific examples 2 to 8 have different manganese and magnesium contents, and have different The rolling temperature and rolling amount are used to prepare test pieces 2 to 8 respectively.

Comparative Example 1 This Comparative Example 1 is a manufacturing method using a conventional aluminum-magnesium alloy plate. It first prepares an aluminum-magnesium alloy blank with a composition ratio as follows: 0.12 wt% silicon, 0.31 wt% iron, 0.03 wt% copper, 0.45 wt% manganese, 4.6 wt% magnesium, 0.07 wt% chromium, 0.02 wt% titanium, and the remaining content of aluminum. Next, the aluminum-magnesium alloy blank is homogenized and preheated, and then hot-rolled to obtain an aluminum-magnesium alloy sheet, and then subjected to a cold rolling process with a rolling reduction of 20% to obtain an aluminum-magnesium alloy sheet. The aluminum-magnesium alloy sheet was further annealed (annealing temperature: 225 ° C./3 hours), and then cooled to room temperature within 3 hours to obtain the comparative test piece 1. Homogenization conditions: above 400 ° C / 2 hours + above 500 ° C / 8 hours Preheating conditions: above 450 ° C / 1 hour Hot rolling conditions: finish rolling temperature 400 ° C cold rolling conditions: rolling amount is 20%

Comparative Example 2 The manufacturing method of Comparative Example 2 is substantially the same as that of Comparative Example 1, except that the aluminum-magnesium alloy billet of Comparative Example 2 has different rolling amounts and annealing conditions to obtain comparative test piece 2 .

The composition and relative proportions of the aluminum-magnesium alloy alloy blanks of the foregoing specific examples 1 to 8 and comparative examples 1 and 2 are summarized in Table 1, and then the specific examples 1 to 8 and comparative examples 1 and 2 are prepared. Finishing temperature, rolling amount, and magnesium content of test pieces 1 to 8 and comparative test pieces 1 and 2 are summarized in Table 2.

Table 1

Table 2

Then, the aforementioned test pieces (test pieces 1 to 8 and comparative test pieces 1 and 2) were respectively subjected to a corrosion resistance test, a strength test (a drop strength, a tensile strength), and a tensile test.

The anti-corrosion test specifications are in accordance with ASTM B928. The test piece is sampled in the vertical rolling direction, 60mm wide and 120mm long. The test piece is placed in acetone (CH ₃ ) ₂ CO to remove surface oil, and then immersed in an aqueous solution of 80 ° C and 5% NaOH After 1 minute, rinse with water, soak in HNO ₃ for 30 seconds, and then rinse with distilled or deionized water, then air dry. The amount of test liquid used depends on the area of the test area of the test piece, and its ratio is 100L / m ² (0.1 mL / mm ² ) or more. The test piece is vertically placed in a tank containing the test solution, and the distance between the bottom of the tank and the liquid surface is more than 25mm. The temperature of the solution is maintained at 65 ± 1 ° C, and the test piece is immersed for 24 hours. Then quickly take out and wash with pure water, then immerse in HNO ³ at room temperature and observe until the test piece is clean, then wash with pure water and air dry.

Then use visual inspection and calculate the mass loss rate of these test pieces to determine the surface erosion (Exfoliation (G66)) of the test pieces; and the results of Intergranular corrosion (G67). G66: According to the ASTM G66 test, the corrosion type N / P / E is visually judged (N = no corrosion, P = porosity, E = layer peeling), and the test piece is judged as passing without layer peeling (E). G67: According to ASTM G67, the weight loss / surface area of the test piece after corrosion is calculated. For example: test piece size (mm) (length / width / height) = 20/6/50, test piece surface area = 28.4cm ² , weight before corrosion 16.3065g, weight after corrosion 16.2381g; weight loss 68.4mg; weight loss / test piece surface area ^{= 68.4mg / 28.4cm 2 = 2.4mg /} cm 2.

Strength and tensile test: According to the EN 485-1 standard, the test piece is processed into a flat test piece, and the test piece is tested for drop strength, tensile strength, and tensile length using a universal testing machine.

The corrosion resistance test (G66, G67), drop strength, tensile strength, and tensile results of these test pieces are summarized in Table 3.

table 3 ASTM b928 standard: G67: <15mg / cm ² Dropping strength: ≧ 215MPa Tensile strength: ≧ 305MPa Elongation: ≧ 10%

Refer to Figures 1 to 4. Figures 1 and 2 are metallographic photos and surface optical photos of test piece 1 after anti-corrosion test. Figures 3 and 4 are metallographic photos and surface optical photos of test piece 1 after anti-corrosion test. . It can be clearly seen from FIGS. 1 and 2 that the aluminum-magnesium alloy plate phase prepared through the embodiment of the present invention has a small b phase and discontinuous precipitation at the grain boundary, so it can achieve a significant anti-corrosion effect, compared with the traditional process. The obtained aluminum-magnesium alloy plate (such as the comparative test piece x in this case) can be clearly seen from Figs. 3 and 4 that the phase b is large and continuously precipitated. Therefore, the anticorrosive effect is poor. And according to the results in Table 3, it is clear that compared to the aluminum-magnesium alloy plate produced by the conventional process, the aluminum-magnesium alloy plate produced by the process method of the present invention has a corrosion resistance (G67) characteristic (less than 2.71). mg / cm ² , the best can reach about 1.83mg / cm ² ) and the strength performance are better than the corrosion resistance and strength of the conventional aluminum-magnesium alloy plate. This shows that the aluminum-magnesium alloy prepared by the aluminum-magnesium alloy method of the present invention The board really improves its corrosion resistance and maintains high strength.

In summary, the present invention utilizes the control of the magnesium and manganese content of the aluminum-magnesium alloy alloy blank, and the combination of increasing the rolling amount and rolling temperature can not only improve the strength of the aluminum-magnesium alloy plate produced, but also because The high rolling amount allows the aluminum-magnesium alloy to rapidly cool down during the rolling process, reducing the generation of easily corroded structures. Therefore, it can also effectively improve the corrosion resistance of the aluminum-magnesium alloy plate, and it can be more widely used. Therefore, the purpose of the invention can be achieved.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited in this way, any simple equivalent changes and modifications made in accordance with the scope of the patent application and the content of the patent specification of the present invention are still Within the scope of the invention patent.

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Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a metallographic photograph illustrating the test piece 1 after the corrosion resistance test FIG. 2 is an illustration of the test piece 1 after the corrosion resistance Optical photo of the surface after the test; FIG. 3 is a metallographic photo illustrating the comparative test piece 1 after being subjected to the corrosion resistance test; FIG. 4 is an optical photo of the surface of the comparative test piece 1 after being subjected to the corrosion resistance test.

Claims (9)

A method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium-based sheet material, comprising: performing an aluminum-magnesium-based alloy blank at a rolling temperature of 250-300 ° C and a rolling reduction of 55-80%. It is obtained after hot rolling, wherein the composition of the aluminum-magnesium alloy includes: 0.09 to 0.14 wt% silicon, 0.17 to 0.31 wt% iron, 0.01 to 0.07 wt% copper, 0.46 to 1.5 wt% manganese, 3.5 ~ 6.0wt% magnesium, 0.06 ~ 0.09wt% chromium, no more than 0.01wt% titanium, and the remaining content of aluminum. The method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium sheet material according to claim 1, wherein the aluminum-magnesium alloy does not need to be annealed after rolling. The method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium sheet material as described in claim 1, wherein the magnesium content of the aluminum-magnesium alloy is between 3.97 and 4.80 wt%. The method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium sheet material according to claim 3, wherein the magnesium content of the aluminum-magnesium alloy is between 4.10 and 4.80 wt%. The method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium sheet material according to claim 1, wherein the manganese content of the aluminum-magnesium alloy is between 0.46 and 0.8 wt%. The method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium sheet material according to claim 1, wherein the rolling reduction is controlled to 60 to 80%. The method for manufacturing a high-strength and corrosion-resistant aluminum-magnesium sheet material according to claim 1, wherein the rolling temperature is between 260 ° C and 285 ° C. An aluminum-magnesium-based sheet having high strength and corrosion resistance, wherein the aluminum-magnesium-based sheet is produced by the manufacturing method described in claim 1, and the intergranular corrosion (G67) thereof is not more than 10.0 mg / cm ² . The aluminum-magnesium-based sheet material according to claim 8, wherein the intergranular corrosion (G67) of the aluminum-magnesium-based sheet material is not more than 5.0 mg / cm ² .