JP2721946B2 - Aluminum alloy material for blinds and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy material for blinds and a method for producing the same, particularly excellent in cold rollability after solution treatment and after baking for a total of 50 s or more at 230 ° C. or less. The present invention also relates to an aluminum alloy material for blinds with a small decrease in strength and a method for producing the same.

[0002]

2. Description of the Related Art Since blind materials require a certain level of strength and corrosion resistance, thin sheets of aluminum alloy are often used.
% Mg-0.25% Cr-based), 5086 (Al-4% Mg-0.5% Mn-0.15%
Cr-based), 5182 (Al-4.5% Mg-0.35% Mn-based)
Rolled sheets of Mg-based aluminum alloy having a thickness of 0.1 to 0.2 mm have been used. In general, since the blind is used after being painted, the aluminum alloy material for the blind is desired to be a material that does not soften by baking treatment after painting. In paint baking treatment, which is performed at a temperature of about 230 ° C. for 40 to 50 seconds, the strength, especially the proof stress, tends to be reduced, and the performance as a blind is often reduced.

As an aluminum alloy material for blinds having improved strength characteristics, an Al alloy containing 4% Mg and 1% Zn (Japanese Patent Application Laid-Open No. 60-251245), and an Al alloy further containing 1% Cu (Japanese Patent Application Laid-open No. No. 61-15937), 2% Cu, 1%
Al alloy containing Mg and 1% Si (JP-A-61-15938),
Alloys based on Al-Mg-Mn-Fe
205050, 205051, 205052), 2% Mg, 1% Mn, 0.
An Al alloy containing 35% Cu (Japanese Patent Application Laid-Open No. 4-88145) has been developed. The manufacturing method is as follows: 2% Mg, 1% Mn, 0.1% Mn.
After hot rolling an Al alloy containing 35% Cu, solution treatment is performed in the middle of cold rolling, and the final rolling degree is increased to increase the strength (Japanese Patent Laid-Open No. 4-88145). Primary and secondary cold rolling before and after intermediate heat treatment using thin slabs to increase strength and impart strength
(JP-A-2-25546) has been proposed.

However, in these aluminum alloys, when the cold working rate is increased to secure the strength,
For example, when the rolling process is performed at 70% or more, since the final plate thickness is thin, cracks at the plate edge are apt to occur, and the yield of the material is reduced, and the rolling cannot be performed in some cases. In addition, when the degree of rolling is increased, there is a problem that the number of rolling passes is increased and the working efficiency is reduced.

[0005] Recently, colorful blinds have been required in order to improve the comfort of living.
Since the paint baking process is often performed twice by changing the color of the coat (2 coats and 2 bake), the strength decrease is more likely to increase and the aluminum alloy for blinds has a smaller decrease in strength after heat treatment. Development of materials is required.

[0006]

SUMMARY OF THE INVENTION The present invention solves the conventional problems in aluminum alloy materials for blinds and, in order to meet the above-mentioned demands for development, a combination of strength and component elements after a paint baking treatment and a combination of these elements. Of the precipitation mode, cold workability, and combination of additional elements at the paint baking temperature.
i, Mg and Cu amounts were adjusted, and during the coating baking treatment, all of the precipitated Mg was changed to Mg ₂ Si phase or Al-Mg-Cu
Precipitates as a system compound, increases the strength of the alloy by containing excess Si and Cu, further minimizes the content of Mg, and adds Ti in a combination of these components to improve cold workability. It is based on the finding that it is possible to increase the final cold-rolling work rate, even if the final cold-rolling reduction rate is increased, without generating cracks at the plate edge, and reducing the rolling reduction in one pass of rolling. It can be made large and the number of rolling passes can be avoided, and paint baking treatment, for example, 200 to 230 ° C
It is an object of the present invention to provide an aluminum alloy material for blinds that has a small decrease in strength even after performing two paint baking treatments.

[0007]

The aluminum material for blinds according to the present invention for achieving the above object has the following features.
i 0.5-1.5%, Mg 0.3-0.8%, Mn0.
3 to 0.8%, Cu 0.25 to 0.5%, Zn 0.3 to
0.8% and 0.05 to 0.20% of Ti, Fe as an impurity is limited to 0.30% or less, and the balance is Al
And an aluminum alloy cold-rolled plate comprising unavoidable impurities, having an electrical resistivity of 1.3 μΩ · cm or more,
Tensile strength is 400 MPa or less, and 5
The proof stress after the paint baking treatment for 0 second or more is 35
0 MPa or more, and the method for producing an aluminum alloy material for blinds according to the present invention is characterized in that:
5 to 1.5%, Mg 0.3 to 0.8%, Mn 0.3 to
0.8%, Cu 0.25 to 0.5%, Zn 0.3 to 0.
An aluminum alloy containing 8% and 0.05 to 0.20% of Ti, Fe as an impurity is limited to 0.30% or less, and an aluminum alloy including Al and unavoidable impurities is hot-rolled and cold-rolled, 500-550 by continuous annealing furnace
After performing the solution treatment of heating to 70 ° C., the processing rate is 70 to 85.
% Final cold rolling, and the electrical resistivity is 1.3 μΩ · c
m or more, tensile strength is 400 MPa or less, 230 ° C.
The proof stress after performing the coating baking treatment for 50 seconds or more is 350 MPa or more.

The reasons for limiting the components of the aluminum alloy according to the present invention will be described. Si is obtained by precipitating an Mg ₂ Si phase together with Mg at a coating baking temperature (200 to 230 ° C.) and subjecting the alloy to a coating baking treatment. This is effective in reducing the decrease in strength. The preferred content range is 0.5 to
1.5%, and when it is less than 0.5%, the Mg content of the present invention is reduced.
Since the content is as small as 0.3 to 0.8%, the formation of the Mg ₂ Si phase is reduced, and the strength after the baking treatment is reduced. If it exceeds 1.5%, the ductility of the alloy decreases, and cracks tend to occur at the end of the sheet in cold rolling.

Mg, together with Si and Cu, precipitates an Mg ₂ Si phase and an Al—Mg—Cu compound at the paint baking treatment temperature, and is effective in reducing the decrease in the strength of the alloy after the paint bake treatment. is there. The preferred content range is 0.3 to 0.
8% and less than 0.3%, the Mg ₂ Si phase and the Al
-The formation of the Mg-Cu-based compound is small, and the strength is reduced after the baking treatment. If it exceeds 0.8%, the work hardening in cold rolling increases, and the amount of reduction in one pass decreases, leading to an increase in the number of rolling passes and the occurrence of cracks at the ends of the rolled sheet.

Mn has the effect of precipitating Al-Mn compounds in the solution treatment and the paint baking treatment, imparting heat resistance to the alloy material, and reducing the decrease in strength after the paint baking treatment. It is contained in the range. If the amount is less than 0.3%, the effect is small due to the small amount of Mg, and the amount is less than 0.3%.
If the content exceeds 8%, the work hardening in cold rolling increases, and the amount of reduction in one pass cannot be increased.
The number of rolling passes increases, and cracks tend to occur at the ends of the rolled plate. In addition, Al-Fe-Mn-based coarse crystals are formed, which tend to cause cracks during hot rolling and cold rolling, and cause defects such as pinholes.

[0011] Cu precipitates an Al-Mg-Cu-based compound together with Mg at the coating baking temperature, and has the effect of reducing the decrease in the strength of the alloy. The preferred content range is 0.
If it is 25 to 0.5%, and if it is less than 0.25%, the precipitation amount of the Al-Mg-Cu-based compound is small, and the effect of reducing the reduction in strength is small. If it exceeds 0.5%, the ductility of the alloy decreases, and cracks tend to occur at the sheet edge during cold rolling.

[0012] Zn forms a fine MgZn ₂ phase together with Mg at the coating baking temperature, and has the effect of reducing the decrease in the strength of the alloy. The preferred content range is 0.3 to 0.
If it is less than 0.3%, this effect is small, and a yield strength of 350 MPa or more cannot be obtained after baking. If it exceeds 0.8%, work hardening in cold working increases, the ductility of the material also decreases, and cracks tend to occur at the end of the sheet in cold rolling.

[0013] Ti refines the ingot structure of the alloy and forms a fine grain structure during hot rolling and solution treatment.
Without generating cracks at the plate edge in cold rolling,
It is possible to increase the final cold rolling rate. A preferable addition range is 0.05 to 0.20%, and if the addition is less than 0.05%, the effect is small, and if it exceeds 0.20%, a coarse compound of Al ₃ Ti is formed, and cracks are easily generated at the time of hot rolling or cold rolling. It also causes defects such as pinholes in the rolled sheet material.

[0014] Fe forms Al-Fe-Mn coarse crystals, which tend to cause cracks during hot rolling or cold rolling and cause defects such as pinholes in the final rolled sheet. Therefore, it is desirable to keep the Fe content as low as possible in order to obtain the effect of reducing the strength reduction after the coating baking treatment with Mn, but it is necessary to use a high-purity aluminum ingot to reduce the Fe content. Considering that the production cost is high, the alloy composition of the present invention is 0.3%
Is the upper limit.

The aluminum alloy sheet of the present invention has the above composition, and has an electrical resistivity of 1.3 μΩ as a property requirement.
It is essential that the tensile strength is not less than 400 cm and not less than 400 cm. The electrical resistivity affects the softening resistance of the alloy during the baking treatment. In order to improve the softening resistance and generate fine intermetallic compounds of alloying elements such as Si, Mg, and Cu at the time of coating baking, it is necessary to use a material in which these alloying elements are dissolved as solid solution. The resistivity increases with the amount of solid solution, and serves as an index indicating the amount of solid solution. The solid solution state for imparting sufficient softening resistance to the alloy during the baking treatment of the paint is an electric resistivity of 1.3 μΩ.・ C
m or more. Tensile strength is increased by increasing the working ratio of final cold rolling, but when the tensile strength exceeds 400 MPa, cracks tend to occur at the edges of the plate during processing, reducing the yield and making it impossible to roll. It is not preferable because it may be caused.

The production conditions will be described. The aluminum alloy of the present invention is formed into an ingot by continuous casting, for example.
After ingot homogenization, hot rolling is performed according to the usual method,
After cold rolling to the specified thickness, 500-55 in a continuous annealing furnace
Perform a solution treatment by heating to 0 ° C. The continuous annealing furnace performs heat treatment by continuously passing a heating zone while rewinding a metal plate coil, and is well known as an aluminum plate annealing facility.

By performing a solution treatment in a continuous annealing furnace,
Mg ₂ Si phase or Al-Mg-C precipitated by hot rolling
The u-type compound is re-dissolved in the matrix and reprecipitated by paint baking, thereby delaying the recovery of the processed structure and reducing the strength reduction after the paint baking. The solution treatment is performed by heating to 500 to 550 ° C. If the heating temperature is lower than 500 ° C, the Mg ₂ Si phase or Al-M
If the g-Cu-based compound is not sufficiently re-dissolved and the heating temperature exceeds 550 ° C, the eutectic formed in the alloy melts and cracks during annealing or final cold rolling. May occur. It is not necessary to particularly define the heating rate until the solution treatment temperature is reached, but the cooling rate from the solution treatment temperature is preferably maintained at about 10 ° C./s or more. If the cooling rate is slow, Mg ₂ Si
The phase and the Al-Mg-Cu-based compound are coarsely precipitated, and these fine precipitates are reduced during the coating baking treatment, so that the strength decrease after the coating baking treatment is increased.

The final cold rolling performed after the solution treatment is necessary for increasing the strength of the alloy sheet by work hardening and maintaining the strength of the sheet after the paint baking treatment. The preferred rolling reduction ratio is 70 to 85%, and if it is less than 70%, the yield strength of the alloy after the paint baking treatment, particularly the treatment by two coats and two bake, cannot be 350 MPa or more. When the cold rolling ratio exceeds 85%, the strength of the sheet increases, but dislocations accumulate and the strain energy inside the sheet becomes too large.
Since the processed structure is easily recovered at the time of heating in the paint baking treatment, the yield strength after the paint baking treatment is less than 350 MPa. In addition, cracks tend to occur at the end of the sheet during cold rolling.

[0019]

The present invention has the above-mentioned structure and comprises S in the alloy component.
The amounts of i, Mg, Mn, Cu and Zn are adjusted, and due to the interaction of these elements, intermetallic compounds between these elements or between these elements and Al are finely precipitated in the alloy matrix during the coating baking treatment. By reducing the strength of the alloy after the paint baking treatment, by limiting the Fe content and adding Ti, it is possible to perform cold rolling under high pressure without causing cracks at the end of the rolled sheet, thereby improving the strength of the alloy. After performing a heat treatment at 230 ° C. or less, which is equivalent to a paint baking treatment, for 50 seconds or more, a proof stress of 350 MPa or more is ensured.

[0020]

Hereinafter, examples of the present invention will be described in comparison with comparative examples. Example 1 An aluminum alloy shown in Table 1 was melted by a conventional method and formed into an ingot by continuous casting. The ingot was homogenized at 500 ° C. for 8 hours and then hot-rolled to a thickness of 2.5 mm. The hot rolling end temperature was adjusted to 290 to 330 ° C. Then, after cold rolling at a working ratio of 70%, a solution treatment was performed using a continuous annealing furnace. The solution treatment was performed under the conditions of raising the temperature to 500 ° C. at a rate of temperature rise of 10 ° C./s, holding at this temperature for 10 seconds, and then cooling to room temperature at a cooling rate of 10 ° C./s. In the final cold rolling after the solution treatment, a working rate of 80% was given in 6 passes, and a test material having a thickness of 0.15 mm was obtained.

[0021]

[Table 1]

With respect to the test materials, the degree of occurrence of cracks at both ends of the final rolled plate was visually observed. If no cracks were detected, ○ indicates that the crack length was 5 mm or less, and Δ indicates that the crack length exceeded 5 mm. Was evaluated as x. In addition, a tensile test was performed to measure tensile strength, proof stress, and elongation, and the sample was heated at 230 ° C for 100 seconds using an oil bath, assuming a 2-coat 2-bake baking treatment. about
Tensile performance was measured with a JIS No. 5 tensile test piece, and the proof stress reduction rate after the heating was evaluated by the following formula. Yield reduction rate (%) = (Yield strength after final cold rolling-Yield strength after heating) / (Yield strength after final cold rolling) x 100 Further, the electric resistance value (R) is measured at both ends of the test piece by current lead wires. , The lead wire was connected to a DC power supply and an ammeter, and a voltage lead wire was spot-welded to both ends of the test piece, the voltmeter was connected to the lead wire, and the whole was immersed in liquid nitrogen. Then, a DC current was passed from a power supply, and the current value (I) and the voltage value (V) were measured by a DC four-terminal method, and the electrical resistivity was obtained by the following equation. Electric resistivity (ρ) = R × S / L, where R = V / I,
S: cross-sectional area of test piece, L: distance between voltage terminals Table 2 shows the measurement and evaluation results.

[0023]

[Table 2]

As shown in Table 2, none of the test materials produced according to the present invention had cracks at the edges of the final cold-rolled sheet material, and the proof stress after heating at 230 ° C. for 100 seconds was 35.
At 3 MPa or more, a decrease in yield strength after heating was 7.1% or less, showing good results.

Example 2 For test materials No. 1, No. 4 and No. 6 of Example 1, solution treatment and final cold rolling were performed under the conditions shown in Table 3, and the same method as in Example 1 was used. Various performances were evaluated. Table 4 shows the results. The solution-treated material has a thickness adjusted to a final thickness of 0.15 mm, and has been subjected to predetermined cold rolling. The heating rate in the continuous annealing furnace was set to 10 ° C / s. As shown in the results in Table 4, the test materials manufactured using the aluminum alloy of the present invention and manufactured under the conditions of the present invention did not have any cracks at the edge of the final cold-rolled sheet material, The proof stress after heating at 100 ° C. for 100 seconds was 353 MPa or more, and the rate of decrease in proof stress was 7.1% or less, indicating good performance.

[0026]

[Table 3]

[0027]

[Table 4]

Comparative Example 1 An aluminum alloy having a composition shown in Table 5 was used in Example 1.
Casting, homogenization, hot rolling, cold rolling, solution treatment, and final cold rolling were performed in the same manner as described above to produce a test material having a thickness of 0.15 mm. Various properties of these test materials were evaluated in the same manner as in Example 1. Table 6 shows the evaluation results.
In Table 5, those which are outside the component limits of the present invention are underlined.

[0029]

[Table 5]

[0030]

[Table 6]

As shown in Table 6, in the test material using the aluminum alloy out of the composition limitation of the present invention, cracks occurred at the end of the final cold-rolled sheet or the proof stress decreased after heating. Since the test material No. 1 had a low Si content, cracks occurred at the plate edge, and the proof stress after heating at 230 ° C. also decreased. No. 2 had a Si content exceeding 1.5%, and No. 3 had a Fe content exceeding 0.30%, so that cracks occurred at the plate edges in all cases. No. 4 had a large decrease in proof stress after heating because of a low Cu content, and No. 5 had a crack during final cold rolling because of a Cu content exceeding a limited range. No. 6 has a low Mn content and No. 8 has a low Mg content.
No. 7 has a large decrease in proof stress after heating.
No. 9 had a large amount of Mg, so cracks occurred at the end of the plate during the final cold rolling. No. 10 had a large decrease in proof stress after heating due to a small Zn content, and No. 11 had cracks at the plate edge because the Zn content exceeded the limited range. In No. 12, cracks occurred during cold rolling because the Ti content exceeded the limited range.

Comparative Example 2 For the test materials No. 1, No. 4 and No. 6 prepared in Example 1,
Solution treatment and final cold rolling were performed under the conditions shown in Table 7, and various performances were evaluated in the same manner as in Example 1. Table 8 shows the evaluation results. The final thickness of the solution heat treated material is
It has a sheet thickness adjusted to 0.15 mm and is subjected to predetermined cold rolling. Heating rate in continuous annealing furnace is 10 ℃
/ s, and the heating rate of the batch furnace was 50 ° C./s.

[0033]

[Table 7]

[0034]

[Table 8]

As shown in Table 8, test materials prepared by solution treatment or final cold rolling that do not satisfy the conditions of the present invention (in Table 7, those that do not satisfy the conditions of the present invention are underlined) ), The proof stress was reduced or the plate edge was cracked. For test materials No. 13 and No. 15, re-dissolution of alloying elements was insufficient due to low solution treatment temperature,
A decrease in proof stress occurred. In No. 14, since the solution treatment temperature was high, eutectic melting occurred partially, and cracks occurred at the end of the sheet during final cold rolling. In No. 16, sufficient work hardening was not obtained because the final cold rolling reduction was below the lower limit, and the proof stress after heating was low. For test material No. 17, the final cold rolling reduction exceeded the limited range, cracks occurred at the plate edge, and at the same time, the processed structure was easily recovered by heat treatment at 230 ° C, and the reduction in proof stress increased . No. 18, No. 19, and No. 20 were all subjected to solution treatment in a batch furnace to obtain fine precipitation of Mg ₂ Si phase and Al-Mg-Cu based compound at 230 ° C heating. Since the solid solution state is not achieved, the proof stress after heating is low, and the proof stress is greatly reduced.

[0036]

According to the present invention, there is provided an aluminum alloy material for blinds having improved final cold workability and having a small decrease in strength after baking even when a two-coat or two-bake baking treatment is performed. You. 1 in cold rolling
Since the rolling reduction per turn can be increased, the production efficiency is also improved.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location C22F 1/00 673 8719-4K C22F 1/00 673 689 8719-4K 685Z 686 8719-4K 686A 691 8719 -4K 691B 694 8719-4K 694A

Claims (2)

(57) [Claims] 1. Si 0.5-1.5% (mass%, the same applies hereinafter), Mg 0.3-0.8%, Mn 0.3-0.8%,
Contains 0.25 to 0.5% of Cu, 0.3 to 0.8% of Zn, and 0.05 to 0.20% of Ti;
e is a cold rolled plate of an aluminum alloy containing 0.30% or less, and the balance being Al and unavoidable impurities, having an electric resistivity of at least 1.3 μΩ · cm and a tensile strength of 4
An aluminum alloy material for blinds, which has a proof stress of not more than 00 MPa and not less than 350 MPa after a coating baking treatment at 230 ° C. or less for 50 seconds or more. 2. 0.5% to 1.5% of Si, 0.3% of Mg
0.8%, Mn 0.3-0.8%, Cu 0.25-0.
5%, Zn 0.3-0.8% and Ti 0.05-0.
An aluminum alloy containing 20%, Fe as an impurity is limited to 0.30% or less, and an aluminum alloy consisting of the balance of Al and inevitable impurities is hot-rolled and cold-rolled, and is heated to 500 to 550 ° C. by a continuous annealing furnace. After performing the solution treatment by heating, the final cold rolling is performed at a working ratio of 70 to 85%, the electric resistivity is 1.3 μΩ · cm or more, the tensile strength is 400 MPa or less, and the temperature is 230 ° C. or less. Is 350MPa after baking for more than 50 seconds.
A method for producing an aluminum alloy material for a blind, characterized by the above.