JPS5819734B2 - Aluminum and aluminum alloy plate materials with excellent formability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the formability of non-heat treated semi-hard aluminum and aluminum alloy plates.

Aluminum plates for molding, which are widely used as materials for heat exchange fin materials, cap materials, can materials, etc., include industrial pure aluminum such as JISA 1050 (A7 purity of 99.0% or more) or JIS A
300 (Mn 1.0-1.5%, CuO,0
5-0.20%), and the balance between strength and elongation is important when selecting a material, but when actually processed, even if the materials have the same strength and elongation, the molding performance will be different. There are some cases where clear differences can be recognized.

In addition, in order to improve forming performance, the final tempering conditions may be changed to reduce strength and increase elongation, but increasing elongation and improving forming performance are not necessarily linked; Currently, we are struggling with countermeasures such as reviewing chemical ingredients and manufacturing processes in order to strike a balance between growth and growth.

In addition, with the recent rise in the price of aluminum ingots, there is a strong demand for aluminum plates for forming processing to be thinner in order to save resources and be inexpensive.

However, the soft plates (0 material) and 2
Hard plates (H22 material) do not have sufficient strength and may buckle during transportation, and furthermore, if such materials are used to achieve a thin wall ratio, formability may be poor during molding. This was recognized and hindered the thinning of aluminum plates for forming processing.

The present invention has been made based on the above circumstances,
The purpose of this work is to provide pure aluminum and aluminum alloy semi-hard plate materials with higher strength and excellent formability, to achieve thinner materials, and to contribute to saving aluminum resources.

That is, the present invention (translation (1)) formability with Al purity of 99.0 wt% or more, characterized in that at least 60% or more of the area covered by fine subcrystalline grains with an average grain size of 3 μ or less is included. Patents 1, 0 to 2 are characterized in that: (2) an area covered with fine subcrystalline grains with an average grain size of 3 μ or less is included in an area ratio of at least 60% or more; 1.5 wt%, CuO, 05~
It is an aluminum alloy semi-rigid plate material with excellent formability, containing 0.2 wt% and the remainder M and impurities.

The present inventors have developed an industrial pure aluminum plate (A
7 purity 99.0 wt% or more) and A I-M n-C
As a result of intensive research on U-based aluminum alloy plate (3003), we found that O material and H22 material are insufficient in terms of strength in order to prevent bending during transportation and to achieve a thin wall ratio, and semi-hard material (
HI3. It was found that a strength level of H24, H34) is required, and that the molding performance of semi-hard materials strongly depends on the grain size of fine subcrystalline grains and their area ratio.

That is, if the average subgrain size is 3 μ or more, sufficient forming performance cannot be obtained and strength is insufficient, and the area ratio of the subgrain region is 60%.
If the remainder is a processed structure or recrystallized grains, the former has poor formability and cannot withstand harsh forming conditions;
It has been found that the latter has poor moldability and lacks strength.

Therefore, in order to improve formability, it is necessary to create a structure in which 60% or more of the area is covered with subcrystalline grains of 3 μm or less in area.

There is still no established theory regarding the improvement of formability due to subcrystalline grains, but because the material is covered with fine subcrystalline grains, processing strain during forming is uniformly distributed, ductility increases, and cracking is suppressed. At the same time, it is presumed that this is due to the improved strength due to the fine grain effect (Hall-Petsch relationship), which eliminates problems such as buckling during transportation, and allows for sufficient resistance to molding even when the wall thickness is reduced.

In addition, even with the same semi-hard material, even a so-called mixed structure in which a recrystallized region of several micrometers or more and a non-recrystallized region are mixed, has the strength and strength that meet the JIS standard.
Although the standard value for elongation can be satisfied, it is thought that the mixed structure cannot withstand severe forming processing because processing strain concentrates in the recrystallized region during forming processing, making it easy to break.

This effect is remarkable in so-called multi-stage forming processes, such as fin forming in a cross-fin type radiator, in which a plate material is stretched and then the holes are expanded. Hole expandability deteriorates significantly, but with the sheet material mainly composed of fine subcrystalline grains according to the present invention, the distance traveled by the dislocations introduced in the first stage processing is short, so it is difficult to expand the hole during the second stage processing. It is estimated that the moldability is hardly impaired and shows good moldability.

The materials applied to the present invention are industrial pure aluminum and A7, which are widely used for molding as described above.
-Mn-Cu type 3003 alloy, and these materials exhibit excellent formability in semi-hard materials, as will be clarified in the examples described later.

This industrial pure aluminum has an Al purity of 99.0% or more as specified in the JIS standard, and if it is less than this,
The good moldability of pure A7 is lost.

In addition, Al-Mn-Cu based 3003 alloy is also Mn
1.0-1.5 wt%, CuO, 05-0.2w
t%, the remainder 11' and impurities, and M
If n is less than 1.0 wt%, corrosion resistance is insufficient, and if Mn is less than 1.0 wt%.
If it exceeds 5wt%, giant crystallized substances will occur during casting, and C
If u is less than 0.05 wt%, sufficient strength cannot be obtained, and Cu
If the content exceeds 2wt, the corrosion resistance will be poor.

In order to make the aluminum (alloy) plate material of the present invention have a desired fine subgrain structure, an ingot melted and cast according to a conventional method may be hot-rolled as it is or after a predetermined cold rolling process.
After intermediate annealing at a temperature of .degree. C. or lower, cold rolling is performed at a rolling reduction of 80% or higher, followed by tempering at a temperature of 300.degree. C. or lower.

At this time, it is desirable that the thermal refining be performed at as low a temperature as possible for a long period of time in order to prevent coarsening of crystal grains.

In the present invention, the aluminum ingot contains Fe, Mn,
Cu, Mg.

It is necessary to hot-roll by adding Cr or impurity components to a solid solution state, and this requires homogenization treatment at high temperature for a long time, soaking below the precipitation temperature range, or simply heating to the hot rolling start temperature. This is achieved by heating the ingot.

The components thus dissolved become fine precipitates during hot rolling or intermediate annealing, and contribute to making the cell size of dislocations generated during final cold rolling fine.

The cell structure formed by dislocations is closely related to the size of the subgrains formed during the final heat treatment, and the finer the cells, the finer the subgrains.

Therefore, the higher the final cold rolling rate, the finer the cells, and the more fine the subgrain structure can be obtained. Casting solidification is performed as quickly as possible to increase the amount of melt.

It is desirable to increase the final cold rolling rate.

In order to obtain the aluminum (alloy) plate material of the present invention, as mentioned above, it is common to use the so-called H24 treatment in which work hardening treatment is followed by annealing to make a semi-hard material, and the material is saved as a thin-walled hard material. can be achieved.

Examples of the present invention will be described below.

Example 1 JISA1050 alloy (A7≧99.5wt%) was melted and cast into two ingots, subjected to homogeneous heat treatment at 540°C for 4 hours, and then the -force was applied to a plate thickness of 400mm to 20mm.
Sample material (5) was obtained by hot rolling to a plate thickness of 400 mm and then cold rolling to a plate thickness of 0.15 mm.
The sample material (B) was hot rolled to a thickness of 6 mm and then cold rolled to a thickness of 0.15 mm.

Sample materials (A) and (B) were subjected to final tempering (H24) at 240° C. for 2 hours after completion of cold rolling, and then subjected to tests for mechanical properties and forming performance.

Table 1 shows the measurement results for mechanical properties and molding performance, and Figure 1A.

B shows the transmission electron microscope structure of sample material (5) and (B) magnified 7500 times.

According to JIS H4000, the mechanical properties of A1050P-H24 plate material with a plate thickness of 0.2 to 0.3 trun are 10 to 14/9/mm2 in tensile strength and 1% or more in elongation. The tensile strength of plate material (5) meets the JIS standard, and at the same time, the elongation has dramatically improved and it shows good formability.
This has been achieved in a thin manner.

Example 2゜JISA3'003 alloy (An-1,25wt%M
After melting and casting n-0, 10wt%Cu) into an ingot, it was homogenized at 425℃ for 2 hours, and then the plate thickness was determined *1
Hot rolling from 40mm to 6mm.

After hot rolling, immediately cold rolled to a thickness of 0.15 mm (C); after hot rolling, intermediate annealing at 300°C and then cold rolled to a thickness of 0.15 mm (C) After hot rolling and intermediate annealing at 450℃, the plate thickness is 0.1
Three types of test materials (E) were prepared by cold rolling to a thickness of 5 mm, and each material was subjected to final tempering (H) at 300°C for 1 hour.
Table 2 shows the mechanical properties and molding performance when performing 24), and 75 for sample materials (C) and (E).
A transmission electron microscope structure at 00x magnification is shown in FIG. 2 C2E.

According to Table 2, the plate materials (C) and (D) of the present invention have excellent strength and formability, but the test material (E), which has a slightly lower subgrain area ratio, has a lower strength. Hole expandability is also poor.

As stated above, the plate material of the present invention is a semi-hard material with excellent formability, so conventionally soft materials were not used from the viewpoint of workability.
It is possible to thin the cross fin coils used in the condensers and evaporators of room coolers and car coolers without impairing handling. It can be applied to complex forming processes such as hole expansion, bending, flushing, etc. and multi-stage forming processes, and has extremely high utility value industrially.

[Brief explanation of the drawing]

FIGS. 1A and 1B and 2C are transmission electron micrographs (magnification: 7500 times) of the plate material of the present invention. Figure 2E is a transmission electron micrograph of the comparative plate material (magnification: 7
500 times).

Claims (1)

[Scope of Claims] 1. A formable material having an Al purity of 99.0 wt% or more, characterized in that at least 60% or more of the region covered by fine subcrystalline grains with an average grain size of 3 μm or less is contained in terms of area ratio. Superior pure aluminum semi-rigid plate material. 2. Mn 1.0-1.5 wt%, CuO 105-105, characterized in that at least 60% or more of the area covered by fine subcrystalline grains with an average grain size of 3 μ or less is included.
A semi-rigid aluminum alloy plate material with good formability, containing 0.2 wt% and the balance being Al and impurities.