JP2002155331A - Method for producing aluminum alloy clad plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost method for brazing an aluminum lap joint which is excellent in working easiness in the air while requiring no flux. SOLUTION: Aluminum thin clad sheet materials are previously inserted into the lap boundaries of several aluminum base materials. The aluminum base materials are brazed and hot-rolled to produce an aluminum alloy clad plate. In the production, the aluminum thin clad sheet materials 3 are consisting of three or five layers. The layer below the surface material is consisting of a brazing filler metal whose melting point is <=600 deg.C. Mg of 0.1 to 6% and possibly Bi of 0.01 to 1% are added to either one or more constitutional members. The whole of the clad members is heated to the liquidus temperature of the brazing filler metal or higher and to a range where the lowest value of the solidus temperature of each member is not exceeded while they are closely adhered under pressure. In this way, the plural aluminum base materials are brazed. After that, a rolling is performed thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a low-cost, high-precision aluminum alloy laminated plate having a high clad ratio, which allows a wider range of member combinations.

[0002]

2. Description of the Related Art A laminated plate of an aluminum alloy is mainly used for a brazing sheet in which a brazing material and a core material are combined. This brazing sheet is used in heat exchangers for automobiles, for example, radiators and coolers, and its usage is increasing year by year. Also, the variation of the alloy composition to be combined with the number of layers tends to increase.
The manufacturing method of this laminated plate is usually performed by hot press bonding in which the thin brazing material and the core material are heated in a superposed state and hot rolling is performed as it is.

[0003]

In this hot press bonding, in order to ensure the press bonding between the skin material and the core material, it is necessary to effectively expose an active new surface due to the destruction of the surface oxide film of both members. Therefore, there is a limitation in the alloy combination of the members, for example, a combination in which the extensibility between the two members is different is preferable. Further, since the extensibility differs in the thickness direction, the combination of the thickness of the members and the number of combinations are limited, and it is difficult to press the crimp especially with an extremely thick skin material or an extremely thin skin material. Also, in rolling to complete compression, the extensibility of the skin material and the core material is different, so the clad ratio (the ratio of the skin material thickness to the total thickness) fluctuates greatly at the ends in the longitudinal and width directions, and a predetermined clad ratio is obtained. There is a problem that the yield is low and the material yield is low. In addition, although the clad ratio range is within a predetermined range, the dispersion is large, and it is not enough to meet the strict quality requirements that are becoming more severe year by year. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to manufacture a low-cost, high-precision aluminum alloy laminated plate with a high clad ratio, which can expand the range of member combinations of the laminated plate.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, in the present invention, brazing is performed in place of the conventional hot press bonding in the production of a laminated plate, and the brazing is performed by heat. This is performed in a heating furnace before cold rolling under the condition of no air and no flux. At this time, air-free and flux-free brazing can be performed by inserting an aluminum laminated plate material, which is made by coating and protecting a Mg-added solder material or brazing material with an aluminum skin material, at the bonding interface and applying pressure and heating. Was found. Here, the brazing is a general term for soldering and brazing. That is, one aspect of the present invention is a method of manufacturing an aluminum alloy laminated plate in which an aluminum laminated plate material is inserted and brazed in advance at a superposed interface of a plurality of aluminum base materials and then hot-rolled. The laminated material is a three-layered laminated material, the core material of which is a brazing material having a melting point of 600 ° C. or less, the skins of which are made of an aluminum alloy having a higher melting point than the core material, and at least the skin material and the core. 0.1-6% Mg (mass%,
The same applies hereinafter) or Bi is added in an amount of 0.01% to 1%, and the whole of the superposed members is pressed and adhered to the solid phase of each member other than the brazing material at a temperature not lower than the liquidus temperature of the brazing material. This is a method for manufacturing an aluminum alloy laminated plate, characterized in that a plurality of aluminum base materials are brazed by heating to a temperature not exceeding the lowest value among the linear temperatures, and then rolling is performed.

[0005] The invention of claim 2 is directed to a method of manufacturing an aluminum alloy laminated plate in which an aluminum laminated plate is inserted in advance at a superposed interface of a plurality of aluminum base materials, brazed, and then hot-rolled. The laminated plate is made of a thin laminated plate having a five-layer structure, and the intermediate material between the both skins and the core is made of a brazing material having a melting point of 600 ° C. or less, and both the skin and the core have a higher melting point than the intermediate material. An aluminum alloy, wherein at least one of a skin material, a core material and an intermediate material is added with 0.1 to 6% of Mg or 0.01 to 1% of Bi, and In the state where the aluminum alloy is pressed and adhered, the aluminum alloy is brazed by heating it to a temperature not lower than the liquidus temperature of the brazing material and not exceeding the minimum value of the solidus temperature of each member other than the brazing material. And then pressure Which is a method for producing an aluminum alloy laminated plate, characterized in that applied. In this specification, brazing is a general term for soldering and brazing.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, the alloy of the aluminum base material only needs to be an alloy having a melting point higher than the melting point of the brazing material to be combined.
50, 1100, 1200, 3003, 3203, 30
04, 4003, 4004, 4104, 4N04, 50
051, 5N01, 6061, 6063, 6N01, etc., and AC1A, AC1B, AC2A, AC
2B, AC3A, AC4A, AC4B, AC4C, AC
5A, AC8A, AC8B, AC8C and the like can be preferably used.

The combination and the number of alloys are not particularly limited as long as they are in accordance with the purpose of use. The total thickness of the three-layer and five-layer aluminum laminated plate materials to be inserted may be generally 0.1 to 1.0 mm. The clad ratio of the brazing material is preferably 10 to 80% of the total plate thickness. If the total thickness and the cladding ratio are less than the lower limits, the production becomes difficult, and the brazing property is reduced due to insufficient brazing material. If the total thickness and the upper limit of the cladding ratio exceed the upper limits, it is not preferable because it is not economical because of an unnecessary thickness or a different alloy having a low melting point is inserted.

[0008] The two-layered material in the three-layer laminated plate material, the two-layered material and the core material in the five-layer laminated plate material, and the core material of the three-layer laminated plate material as the skin material and the core material There is no particular limitation except for the use of an aluminum alloy having a higher melting point than the intermediate material of the base material, the five-layer laminated plate material and the three-layer laminated plate base material.
A 1070, 1050, 1100, 1200, 30
03, 3203, 3004, 4003, 4004, 41
04, 4N045005, 5N01, 5052, 545
4, 5086, 5083, 6061, 6063, 6N0
1 and the like can be preferably used.

A brazing material having a melting point of 600 ° C. or less is used as the core material of the three-layer laminated plate material, the intermediate material of the five-layer laminated plate material, and the intermediate material of the three-layer laminated plate base material. Examples of the brazing material satisfying this condition include metals such as Zn, Sn, and Bi, Al—Si, and Al.
—Cu, Al—Cu—Si, Zn—Al, and Al—Ge alloys can be preferably used. Then, 0.1 to 6% of Mg is added to at least one or more of the constituent members. Mg is effective in improving the wettability of the brazing filler metal when it is melted. If the addition amount is less than 0.1%, the effect is insufficient, and if it exceeds 6%, the addition effect is saturated and becomes meaningless. However, there is a problem that workability is deteriorated, which is not preferable. When the degree of pressure adhesion during brazing heating is strong, Mg may be added to any one of the constituent members, but if the degree of pressure adhesion is not particularly strong, the wettability deteriorates. In this case, it is preferable to add each component to a plurality of components.

In the case of adding to a brazing material such as a core material of a three-layer laminated plate material, an intermediate material of a five-layer laminated plate material, or an intermediate material of a three-layer laminated plate base material, the molten material is naturally Mg Are alloyed. In the case of adding to the skin material and core material of the three-layer laminated material and the core material of the five-layer laminated material or the base material of the three-layer laminated material, the brazing material is melted. At times, the skin material or the core material is eroded by the erosion of intrusion and melting, and Mg is alloyed in the molten brazing material. Which of the components is to be added with Mg, for example, may be added to other components if the rollability of the brazing material is significantly reduced when added to the brazing material.

Further, Bi is preferably added to any one of the constituent members. Especially the aluminum base material to be joined is M
g (containing 3004, 40 in the above example)
03, 4004, 4104, 4N04, 5052, etc.), the wettability of the molten brazing material usually deteriorates, but Bi acts to prevent this deterioration.
It is preferred to add. The amount added is 0.01
%, The effect is not sufficient, and if it exceeds 1.0%, the effect is saturated.
1.0% is desirable.

Further, Li may be further added to these in an amount of 0.01 to 5%.

In the case where a laminated plate is used for at least one of the base materials in place of the insertion type laminated plate system, the total plate thickness is not particularly limited. In this case, the thickness of the base material of the main member constituting the joint may be set at any time according to the purpose of use. Also, an aluminum laminated plate may be used for both. However, the thickness of the skin material and the thickness of the intermediate material (brazing material) at this time are desirably 0.1 to 1.0 mm.

In general, it is preferable to apply a pressure of 0.001 MPa or more to the extent that the entire superposed member is pressed and adhered. In this case, if the load is 0.1 MPa or more, the exudation of wax will occur not only from the cut portion but also from the end of the plate. One way to prevent this is to increase the thickness of the oxide film at the edge of the thin laminated plate. For this purpose, laser and plasma are used for cutting the laminated plate.
It is desirable to perform melting cutting such as arcing.

As another measure for preventing seepage, a thin foil is placed around the overlapping surface so that only the periphery is strongly pressurized so that the molten solder inside from the periphery does not seep outside. It is conceivable that the end of the plate is melted by laser, arc or the like in the entire thickness direction and mixed and alloyed to make the melting point of this portion higher than that of the brazing material alone. The heating of the brazing joint is made to be higher than the liquidus temperature of the brazing material because it is necessary to melt the solder material or brazing material because of the brazing, and the upper limit heating temperature is set for each member other than the brazing material. The reason why the temperature does not exceed the minimum value of the solidus temperature is to prevent deformation and deterioration of members other than the brazing material.

The liquidus temperature of the brazing material is usually 380-5.
90 ° C. The solidification of the brazed member may be carried out at a reduced temperature, or may be carried out by liquid phase diffusion solidification while maintaining the brazing temperature for a long time. At this time, the holding time is not particularly limited, but is preferably about 1 to 10 hours. If the time is less than 1 hour, the diffusion is not sufficient, and if it is 10 hours or more, the diffusion is sufficient, and further heating is meaningless.

The hot rolling temperature may be any value as long as the integrated member is completely solidified.

The reason why the integrated brazing of the present invention is possible in the atmosphere and under the condition of no flux is presumed to be as follows. In other words, in order to enable brazing of aluminum, it is generally necessary to cause wetting of the molten braze, but in order to satisfy this condition, it is necessary to prevent oxidation of the brazing material and the joining base material during brazing heating. It is considered necessary to have an action and an oxide film destruction action. At this time, it is considered that the sensitivity of these two actions is particularly high in the molten brazing material, and that the control of the brazing material needs to be stricter for the base material. Therefore, in the current brazing method, as described above, in order to prevent the oxidation and destruction of the oxide film, heating in a vacuum and simultaneously utilizing the evaporation phenomenon of Mg added to the brazing material (vacuum brazing) or non-oxidizing The use of flux in a non-oxidizing atmosphere (non-corrosive flux brazing in a non-oxidizing atmosphere) has been performed. On the other hand, the prevention of oxidation in the atmosphere and under the condition of no flux according to the present invention is shown in FIGS.
As shown in (1), a highly sensitive brazing material is used as a core material in a three-layer aluminum laminated plate or an intermediate material in a five-layer aluminum laminated plate to prevent direct oxidation by air, and It is considered that the oxidation by the atmosphere is suppressed to the minimum for the base material and the skin material due to the close lap joint. In the present invention, the brazing is possible even though the brazing material is not exposed on the surface, because the brazing material on the inner surface erodes the skin material and melts out on the surface during melting as shown in FIG. Conceivable. At this time, it is considered that the prevention of oxidation of the surface liquefied wax due to erosion is due to insufficient growth of the oxide film immediately after exposure to the surface and the suppression of oxidation by the close joint.

On the other hand, although there is no clear point about oxide film destruction, it is considered as follows. It is considered that Mg in the brazing material works to evaporate and reduce the aluminum oxide film in a very small overlapping space, similarly to vacuum brazing. At this time, the supply of Mg is performed by adding M to one or more of the skin material and the core material (brazing material) in the three-layer aluminum laminated plate material.
g is added, and in the case of adding only the cladding material, the low melting point brazing material is eroded by erosion which penetrates and melts in the cladding material at the time of melting, and Mg is alloyed in the molten brazing material. . In a five-layer aluminum laminated plate, Mg is added to at least one of a skin material, a core material, and an intermediate material (brazing material), and Mg is not added to the intermediate material (brazing material). When the brazing material is melted,
Mg is supplied to the brazing material by eroding the skin material and the core material by erosion of infiltration and melting to form Mg into the molten brazing material.

There are many unclear points about the mechanism by which Bi prevents the deterioration of the wettability of the molten brazing material with respect to the Mg-containing base material, but it is considered as follows. That is, in the case of the Mg-containing base material, the surface oxide film is formed of an Mg-based oxide film, but in this case, the action of reducing the oxide film by Mg in the molten brazing material does not work. Bi under these circumstances M
It has a peel-off action of the g-based oxide film (Materials
Science and Technology, April 1999, p. 419)
It is thought to be.

Incidentally, even if a low melting point metal is inserted into an aluminum alloy, it is possible to minimize the adverse effects such as deterioration of corrosion resistance due to the combination of different metals. This is because the insertion plate is a thin laminated plate as described above, so that the ratio of the dissimilar metal thickness to the total plate thickness after insertion is kept extremely low, and hot working such as hot rolling and annealing after brazing is performed. This is considered to be due to the diffusion of the dissimilar metal over the entire thickness of the sheet due to the addition.

[0022]

EXAMPLE 1 As shown in FIG. 4, a base material 1: Al-1.1% Mn was used as a core material.
Using an alloy (8 mm × 100 × 200 mm), a base material 2: Al-2% Zn alloy (8 mm ×
Base material 3: Al-1.1% Mn alloy (8 mm × 100 × 20 mm) as an intermediate material 1 on the skin side using 100 × 200 mm).
0 mm), base material 4: Al-2% as intermediate material 2 on the core material side
In order to manufacture a seven-layer aluminum alloy laminated plate using a Zn alloy (8 mm × 100 × 200 mm), three types of three-layer laminated plates (each having a cladding ratio of 8% for both sides and a cladding ratio of 0.8%) shown in Table 1 as examples of the invention. The same type (1 mm × 100 × 200 mm) was inserted into each superposed interface of each base material and combined. The 7-layer aluminum alloy composite material was placed in an atmospheric furnace at a temperature shown in Table 1 in a state where the mating surface was strongly pressure clamped using a steel restraining jig. After that, it was held for 5 hours, brazed integrally, taken out and cooled to 370 ° C., and at the time when it was cooled to 370 ° C., the restraining jig was removed and hot rolling was performed to finish to a sheet thickness of 3 mm. Then 0.5 more
The sheet was cold-rolled to a thickness of 2 mm and annealed at 350 ° C. × 2 hours. As a result of observing the plate surface, a plate material having good swelling and peeling and a good clad pressure bonding state was obtained. In addition,
As a comparative example, the same combination as that of the invention example was adopted except that the insertion of the three-layer laminated plate into the lap interface was omitted, and the ends of the lap base material were temporarily fixed by MIG welding as shown in FIG. While being heated to 500 ° C. by hot rolling. As a result, the skin material and the intermediate material 1 and the intermediate material 1 and the intermediate material 2 were pressure-bonded, but the intermediate material 2 and the core material were separated without being pressure-bonded, and cladding of the seven-layer material was impossible. Table 1 shows the structure of the laminated plate, the heating temperature, and the results of the clad pressure bonding.

[0023]

[Table 1]

As a result, it was confirmed that the clad method of the present invention exhibited good bonding properties.

EXAMPLE 2 Base material 1: Aluminum plate Al-1.1% Mn alloy (40 mm × 100 × 200 mm) was used as a core material, and base material 5: Al-10% Si— was used on both surfaces as a skin material. 1.5% Mg
For the production of a three-layer aluminum alloy laminate using an alloy (8 mm × 100 × 200 mm), Table 2 was used as an example of the invention.
The three types of laminated plates of the five-layer structure shown in (5% each on both sides of the cladding rate skin material, 25% of the intermediate material, total dimensions 0.1 mm × 100
× 200 mm) were inserted into each superposed interface of each base material and combined. The three-layer aluminum alloy composite material was integrally brazed in the same manner as in Example 1,
It was rolled to a thickness of 0.5 mm. The cladding ratio distribution in the plate width direction of this plate was examined. The result is shown in FIG. As a comparative example, the same combination as that of the invention example was adopted except that the insertion of the five-layer laminated plate into the lap interface was omitted, and the ends of the lap material were temporarily fixed by MIG welding as shown in FIG. In this state, hot pressing was performed while heating to 500 ° C. Then, the distribution of the cladding ratio in the sheet width direction at a thickness of 0.5 mm was examined in the same manner as in the invention example, and is shown in FIG. Table 2 shows the composition and heating temperature of the laminated plate.
Shown in

[0026]

[Table 2]

As a result, it was confirmed that the clad method of the present invention exhibited stable and good clad ratio distribution characteristics.

[0028]

According to the present invention, the range of combination of the base materials can be expanded, and a laminated plate of an aluminum alloy having a uniform clad ratio distribution can be manufactured.

[Brief description of the drawings]

FIG. 1 shows a combination of components in a brazing method of the present invention. FIG. 1 (a) shows the configuration and arrangement when three layers of aluminum laminated plates are inserted between aluminum base materials.
FIG. 1 (b) shows the configuration and arrangement in the case where five aluminum laminated plates are inserted between the aluminum base materials.

FIG. 2 is a schematic view showing a laminated structure of aluminum laminated plates. FIG. 2A shows a laminated structure of a three-layer aluminum laminated plate, and FIG. 2B shows a laminated structure of a five-layer aluminum laminated plate.

FIG. 3 is a schematic diagram showing the exudation of a brazing material and the spread of the molten brazing material.

FIG. 4 is a sectional view showing a combination of base materials of a seven-layer aluminum alloy laminated plate of Example 1.

FIG. 5 is a schematic diagram showing a state in which an overlapped base material whose ends are temporarily attached by MIG welding is rolled. (Comparative example)

FIG. 6 is a distribution of cladding ratio in a plate width direction.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base material 2 aluminum thin laminated plate material 3 core material of aluminum thin laminated plate material 4 skin material of aluminum thin laminated plate material 5 intermediate material of aluminum thin laminated plate material 6 oxide film 7 base material 1 = core material 8 base material 2 = skin material 9 Base material 3 = Intermediate material 1 10 Base material 4 = Intermediate material 2 11 Temporary weld 12 Rolling roll

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 627 C22F 1/00 627 1/04 1/04 A F28F 21/08 F28F 21/08 D / / B23K 1/00 B23K 1/00 S 1/19 1/19 A 35/40 340 35/40 340J B23K 103: 10 B23K 103: 10

Claims (2)

[Claims] 1. In manufacturing an aluminum alloy laminated plate in which an aluminum laminated plate is inserted and brazed in advance at an overlapping interface of a plurality of aluminum base materials and then hot-rolled, the aluminum laminated plate has a three-layer structure. The core material is made of a brazing material having a melting point of 600 ° C. or less, and the both skin materials are made of an aluminum alloy having a higher melting point than the core material, and at least one of the skin material and the core material 0.1 to 6% (mass%, the same applies hereinafter) or 0.01 to 1% of Bi is further added thereto. Aluminum is characterized by being heated to a temperature not lower than the minimum value of the solidus temperature of each member other than the brazing material and brazing a plurality of aluminum base materials, and then rolling. Manufacturing method of alloy plywood. 2. In the production of an aluminum alloy laminated plate in which an aluminum laminated plate is inserted in advance at an overlapping interface of a plurality of aluminum base materials and brazed and then hot-rolled, the aluminum laminated plate has a five-layer structure. The intermediate material between the both skin materials and the core material is made of a brazing material having a melting point of 600 ° C. or less, and the both skin materials and the core material are made of an aluminum alloy having a higher melting point than the intermediate material, and at least M on any one or more of the skin material, core material and intermediate material
g of 0.1 to 6% or Bi of 0.01 to 1% is added, and in a state where the entire superposed member is pressed and adhered, the temperature is equal to or higher than the liquidus temperature of the brazing material and other than the brazing material. A method for producing an aluminum alloy laminated plate, comprising heating a plurality of aluminum base materials by heating to a temperature not exceeding a minimum value of a solidus temperature of each member, and then rolling.