JPH0813108A - Production of aluminum-manganese-magnesium alloy sheet for building panel - Google Patents

Abstract

PURPOSE:To produce an Al alloy sheet suitable for panel for high temp. baking finish by subjecting a hot rolled plate of Al-Mn-Mg alloy to cold rolling, to process annealing, and further to cold rolling at specific draft and then applying heat treatment to the resulting cold rolled sheet. CONSTITUTION:An ingot of an Al-Mn-Mg alloy, consisting of, by weight, 0.8-1.5% Mn, 0.5-1.5% Mg, and.the balance Al, is heated at 480-620 deg.C for 2-5hr to undergo homogenizing heat treatment and then hot-rolled at 300-500 deg.C into a hot rolled plate of 4-6mm thickness. Subsequently, this hot rolled Al alloy plate is cold-rolled by the conventional method, process-annealed at 320-400 deg.C for 1-3hr, cold-rolled again at 15-25% draft, and successively subjected to final heat treatment at 260-300 deg.C. By this method, the Al alloy sheet for building panel, excellent in strength, flatness characteristic, and bendability after high temp. baking finish, can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exterior panel of a building such as a building, particularly Al-M suitable as a panel for high temperature baking coating.
It also relates to a method for manufacturing an n-Mg-based alloy plate.

[0002]

Al used for exterior panels of buildings
Conventionally, as a plate and an Al alloy plate, A1100-H
14 materials (Al type) and A3003-H24 materials (Al alloy type) are used. These general manufacturing steps are
Ingot-making → homogenizing heat treatment → hot rolling → cold rolling → if necessary, finish annealing (partial annealing) is used to manufacture building board materials (board thickness: 1 to 6 mm), and this board material is used as a curtain wall maker. After cutting into a predetermined size and bending the end portion, surface treatment such as painting or anodic oxidation is performed.

[0003]

In recent years, high-temperature baking coating such as fluororesin coating has been increasing for construction board materials in view of corrosion resistance, weather resistance, stain resistance and the like. But A
For 1100 material, this high temperature baking treatment (usually 240-2
60 ° C.) causes a large decrease in material strength, and there is a problem that the proof stress value (95 N / mm ² ) required for strength design cannot be satisfied. Further, the A3003 material had a problem that cracks were generated during bending (inner radius [R] = 0 ° bending). That is, the ends of these panels are often bent as shown in FIG. 1 (FIG. 1.a). Bending is
The inner radius R = 0 °. At this time, there was a problem of cracking and roughening of the surface (Fig. 1.B). See also Figure 1. There was also a problem that the inside did not bend sharply like Ha.
Further, in any of the materials, there is a problem that the strength and flatness of the plate change during high temperature baking coating. The term "flatness" as used herein means that, when the plate is baked at a high temperature, internal stress of the plate is released, so that the plate is warped or bent, and the flatness changes. This flatness is required for building panels. The present invention, these conventional problems (the problem of strength and stability after high temperature baking coating,
It was made as a result of extensive studies to solve the problems of flatness and bending workability).

[0004]

That is, the present invention is a method for producing an Al-Mn-Mg alloy plate for a building panel, which comprises the following steps and conditions. (1) An ingot obtained by melting and casting an Al-Mn-Mg alloy is
Homogenizing heat treatment by a usual method, hot rolling it (2), then cold rolling it by a usual method, and then annealing it intermediately (3) then rolling it at a rolling ratio of 15- 25
% Cold rolling, (4) then 260-300 ° C
Final heat treatment in.

[0005]

Next, the reason why the method of the present invention is as described above will be explained. Al alloys are limited to Al-Mn-Mg alloys because pure Al alloys such as A1100 and Al-Mn alloys such as A3003 lack sufficient strength.
The Mn-Mg alloy was used. In this case, Mn is 0.8-1.
5 wt% and Mg are preferably 0.5 to 1.5 wt%. Respectively, if it is less than the lower limit, a predetermined strength cannot be obtained, and if it exceeds the upper limit, a coarse intermetallic compound crystallizes and becomes a surface defect,
This is because rolling becomes difficult. If necessary, 0.25 wt% or less of Cu or Cr may be added for the purpose of improving strength and the like. In addition, Ti is used to refine the crystal grains.
You may add 0.05 wt% or less and B0.005 wt% or less. Impurities such as Fe, Si and Zn are general Al.
The degree of inclusion in the metal has no effect on the present invention.

Such an alloy ingot is subjected to a homogenizing heat treatment according to a conventional method and then hot rolling to a plate thickness of 4 to 6 mm. The homogenizing heat treatment is usually performed at 480 to 620 ° C. for 2 to 5 hours, and the hot rolling is usually performed at 500 to 300 ° C. Next, this is cold-rolled and then annealed according to a conventional method. 20 cold rolling
% Or more is preferable. This is because if it is less than this, the material cannot be well kneaded. Annealing is usually 320 to 400 ° C for 1 to 3
Will be carried out for hours.

Next, this is cold-rolled at a rolling rate of 15 to 25%. This is to obtain a predetermined strength by this cold rolling. 1
If it is less than 5%, the strength will be low, and if it exceeds 25%, the strength and flatness after high temperature baking coating will be unstable, and the bending workability will be poor. Next, this cold-rolled sheet is heated to 260 to 300 ° C.
Final heat treatment at. This heat treatment is for stabilizing strength and flatness by high temperature baking coating and for improving bending workability. If the temperature is lower than 260 ° C, these characteristics cannot be obtained, and if the temperature exceeds 300 ° C, predetermined strength cannot be obtained. The heat treatment time is preferably 1 to 3 hours within this temperature range. A produced by the method described above
The l-alloy plate has excellent bending workability, the strength (proof stress) after high temperature baking coating is 90 N / mm ² or more, and the strength and flatness before and after high temperature baking coating are almost unchanged and stable.
It has excellent properties as a building panel material.

[0008]

EXAMPLES Next, examples of the present invention will be described together with conventional examples and comparative examples. Example 1 An alloy having the composition shown in Table 1 as an Al—Mn—Mg-based alloy according to the present invention and A1100 as a conventional alloy.
Alloy (Al-0.15 wt% Cu alloy), A3003 alloy (Al-1.2 wt% Mn-0.15 wt% Cu alloy) are melt-cast, and thickness 600 mm x width 2200 mm x
The ingot had a length of 4000 mm. Both sides (10 mm per side) of this were ground and subjected to homogenizing heat treatment. This was hot rolled at 500 to 300 ° C. to have a plate thickness of 5.0 mm.

After this, each material was manufactured as follows. -Al-Mn-Mg alloy sheet material according to the present invention Hot rolling → Cold rolling → Intermediate annealing → Cold rolling Sheet thickness 4.2 mm 360 ° C x 2H Sheet thickness 3.0 mm → Final heat treatment 280 ° C x 2H ・ Conventional material A1100-H14 sheet material hot rolling → cold rolling sheet thickness 3.0 mm ・ Conventional material A3003-H24 sheet material hot rolling → cold rolling → finish annealing (partial annealing) sheet thickness 3.0 mm 255 ° C. × 3H

Tensile tests (measurement of proof stress values), bending tests and flatness tests shown in Fig. 1.a were conducted on these plate materials. The bending test is shown in Fig. 1. When the inner radius R = 0 ° as shown in b, it was judged by the presence of surface cracks, rough skin, and whether the inner side can be sharply bent (○ good, △ rough, sharply bent). Those that do not exist, x cause cracks). The flatness test is 3mm x 2500mm x 2500mm on Joban.
Put the board of No. 2 and measure the maximum clearance (mm) between the Joban and the board,
Those with a size of 1 mm or less were passed, and those with a size exceeding 1 mm were rejected. The results are shown in Table 1. In addition, these plates were baked and coated with a fluororesin (baking and coating conditions: 250
(° C. × 20 minutes). Tensile tests (measurement of proof stress values) were performed on these plates, and flatness of the plates was measured. The results are shown in Table 1.

[0011]

[Table 1]

As is apparent from Table 1, the material of the present invention is excellent in bending workability and has a high strength after high temperature baking coating (proof strength 90 N / m).
m ² or more) is also excellent, and it can be seen that the strength and flatness before and after high-temperature baking is superior stable and and flatness itself.

[Second Embodiment] N according to the first embodiment of the present invention
o. For the Al-Mn-Mg alloy of No. 1, as shown in Table 2, a plate having a cold rolling rate and a final heat treatment condition within the range of the present invention and a plate outside the range were manufactured and tested. The manufacturing conditions and test methods for the other plates are the same as in Example 1. The results of these tests are shown in Table 2.

[0014]

[Table 2]

As is clear from Table 2, the manufacturing method of the present invention shows that bending workability, strength before and after high temperature baking coating,
It can be seen that the flatness is excellent.

[0016]

As described above, according to the method of the present invention, the strength (proof strength) and bending workability are particularly excellent, and the strength (proof strength) and flatness before and after high temperature baking coating are excellent, as compared with the conventional plate materials for building panels. It is stable and stable, and has excellent flatness itself required for building panels, and is suitable as a plate material for large building panels.

[Brief description of drawings]

FIG. 1 is an explanatory view of a bending process according to the present invention, in which (a) shows a normal state, (b) shows a state in which a crack is generated on the surface, and (c) shows a state in which it does not bend sharply.

[Explanation of symbols]

 1 plate 2 inner radius R = 0 ° part 3 bending surface part 4 crack

Claims (1)

[Claims] 1. A method for producing an Al—Mn—Mg-based alloy plate for a building panel, comprising the following steps and conditions: (1) An ingot obtained by melting and casting an Al—Mn—Mg-based alloy;
Homogenizing heat treatment by a usual method and hot rolling it (2) Then, this is cold rolled by a usual method and then annealed (3) Next, a rolling rate of 15 to 25% Cold rolling at (4), followed by final heat treatment at 260 to 300 ° C.