JP2000303132A - Aluminum alloy brazing sheet excellent in erosion characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al alloy brazing sheet excellent in erosion characteristics and used, e.g. for automobile heat-exchanger parts material. SOLUTION: A brazing filler metal 2, composed of an Al alloy containing 6.0-13.5% (by weight, the same applies to the following) Si or 0.4-5.5% Ge, is laminated on one side or both sides of a core material 1 composed of an Al alloy containing 0.05-2.0% Mn. The core material 1 is composed of an Al alloy further containing, besides Mn, 0.1-5.0% Ca, 0.1-10.0% Li, 0.05-0.8% Sr, 0.05-0.8% Sc, and 0.05-1.0% Y, and further one kind among prescribed amounts of Ti, Zr, V, Nb, Co, Ni, Ba, Be, and Ta. Because Be, etc., precipitate and fix, as compounds, Si and Ge which infiltrate from the brazing filler metal into the core material at the time of brazing, erosion can be controlled and prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Al alloy brazing sheet used as a component material of a heat exchanger for an automobile.

[0002]

2. Description of the Related Art A heat exchanger for an automobile, for example, an evaporator of a car air conditioner is composed of a tube material and a fin material formed by processing an Al alloy brazing sheet, and both are assembled by vacuum brazing or the like.
As the Al alloy brazing sheet, JI
Al alloy such as SA3003 is used as a core material, and Al-S
A clad brazing material such as an i-based alloy or an Al-Ge alloy is used.

In recent years, as part of weight reduction of automobiles, reduction in weight of heat exchangers and, in turn, reduction in thickness of Al alloy brazing sheets have been required. When the thickness of the Al alloy brazing sheet is reduced, it is necessary to reduce the allowable corrosion depth. It is known that when the degree of erosion is large, the eutectic portion becomes a preferential corrosion path, and therefore, corrosion is promoted. For this reason, when the brazing sheet is made thinner as an Al alloy used as a core material of the Al alloy brazing sheet, it is desired to improve not only corrosion resistance but also erosion resistance. The erosion refers to a phenomenon in which the brazing material of the Al alloy brazing sheet erodes the core material during brazing and reduces the thickness of the core material.

As a technique for suppressing such erosion, as described in JP-A-2-153048, in order to complete recrystallization of a core material during brazing,
In order to prevent the sub-grains from remaining, the brazing sheet is previously cold-rolled at a working ratio of 5 to 15%,
There is a technique of annealing at 195 ° C.

[0005]

However, the technology described in the above-mentioned publication adds a cold working and annealing process which is not originally required to the manufacturing process, which complicates the manufacturing process and increases the manufacturing cost. I do.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an Al alloy brazing sheet having excellent erosion resistance, which can be manufactured without adding an extra manufacturing step.

[0007]

The present inventors have found that erosion of the core material in the Al alloy brazing sheet is caused by Si or Ge contained in the brazing material entering the core material during brazing. Focusing on this, based on the technical idea that erosion can be suppressed or reduced if these elements can be deposited as a compound at the very surface layer of the core material before or even after they enter the core material, The invention has been completed.

That is, A of the present invention described in claim 1
1 alloy brazing sheet, Mn: 0.05-2.0
% (Wt%, the same applies hereinafter) of an Al alloy containing Si: 6.0 to 13.5% or Ge: 0.4 to 5.5% on both or one surface of a core material formed of an Al alloy containing An Al alloy brazing sheet in which the brazing material formed by the above is laminated, wherein the core material is Mn and Ca: 0.4.
1 to 5.0%, Li: 0.1 to 10.0%, Sr: 0.
05-0.8%, Sc: 0.05-0.8%, Y: 0.
05 to 1.0%, Ti: 0.17 to 1.0%, Zr:
0.3-1.0%, V: 0.2-1.0%, Nb: 0.
05 to 1.0%, Co: 0.1 to 0.5%, Ni: 0.
05 to 0.5%, Ba: 0.05 to 0.8%, Be:
It is formed of an Al alloy containing one of 0.05 to 0.8% and Ta: 0.05 to 1.0%.

The basic structure of the Al alloy brazing sheet according to the present invention is as shown in FIG.
The core material 1 made of an Al alloy containing 2.0% (wt%, the same applies hereinafter) has a Si content of 0.8 to 2 on both surfaces (see FIG. 1A) or on one surface (see FIG. 1B). The brazing material 2 made of an Al alloy containing 13.5% or Ge: 0.4 to 5.5% is formed by lamination.

The reason why the core material 1 is formed of an Al alloy containing Mn: 0.05 to 2.0% is that Mn is effective for improving the high temperature strength and the strength after brazing. This is because the effect is too small. On the other hand, if it exceeds 2.0%, the effect of improving the strength is saturated, and the moldability is reduced. Preferably it is 0.5 to 1.5%. In addition,
As a core material component, Cu:
0.05-0.8%, Mg: 0.05-0.5%, T
i: 0.05 to 0.3% may be contained. Further, the brazing material 2 is made to contain Si: 6.0 to 13.5% or Ge: 0.
The Al alloy containing 4 to 5.5% is made of S
This is because i and Ge lower the liquidus temperature of Al, and in this range, good fluidity can be obtained when the brazing material is melted. The Al alloy brazing material used in the present invention is composed of Si: 6.0 to 13.5% or Ge: 0.4%.
As long as the content of the element is from 5.5% to 5.5%, the object of the present invention is achieved. However, other elements may be contained as long as the effects of the present invention are not impaired. For example, if Mg is set to 0.
It is effective for an Al oxide film that inhibits brazing properties by containing 0.05 to 2.5%.

According to the first aspect of the present invention, the Al alloy forming the core material 1 includes, in addition to Mn, a predetermined range (a preferable lower limit of each element is the lower limit of the predetermined range × 1.2, and a preferable upper limit is Upper limit of the above predetermined range x 0.8
%) Ca, Li, Sr, Sc, Y, Ti, Zr, V,
It is characterized in that it contains one of Nb, Co, Ni, Ba, Be, and Ta (hereinafter, these elements may be referred to as erosion suppressing elements). The erosion suppressing elements are bonded to Si or Ge which have penetrated the brazing material from the brazing material during brazing and fix these elements as Si compounds (silicide) or Ge compounds. Erosion due to the intrusion of the gas can be effectively suppressed. If the content of each erosion suppressing element is below the lower limit, Si and Ge penetrating the core material from the brazing material cannot be sufficiently trapped as compounds, and the erosion suppressing effect will be deteriorated. On the other hand, when the content of each erosion suppressing element exceeds the upper limit, a large amount of coarse intermetallic compound with Al is formed, which adversely affects mechanical properties and the like. Among the above erosion suppressing elements, in particular, Ca and Li
Is a suitable element because it easily bonds to Si and Ge.

The content range of the erosion suppressing element is as follows:
In the case where individual elements are added alone, even when the addition amount of each element is less than the lower limit, Si and Ge which have entered from the brazing material by the composite addition can be converted into a Si compound or G.
By fixing as an e-compound, erosion can be suppressed and prevented.

According to a second aspect of the present invention, an erosion suppressing element is added to an Al alloy forming a core material in a complex manner, and Mn is 0.05 to 2.0% (wt%, the same applies hereinafter).
Si: 6.0-13.5% or Ge: 0.4- on both surfaces or one surface of a core material formed of an Al alloy containing
An Al alloy brazing sheet in which a brazing material formed of an Al alloy containing 5.5% is laminated, wherein the core material is Ca, Li, Sr, Sc, Y, T in addition to Mn.
It contains one or more of i, Zr, V, Nb, Co, Ni, Ba, Be and Ta, and the content of the contained element is as follows:
Equations (1) and (2) are satisfied. [Ca] /0.1+ [Li] /0.1+ [Sr] /0.05+ [Sc] /0.05+ [Y] /0.05+ [Ti] /0.17+ [Zr] /0.3+ [V] /0.2+ [Nb ] /0.05+ [Co] /0.1+ [Ni] /0.05+ [Ba] /0.05+ [Be] /0.05+ [Ta] /0.05≧1 ... (1) [Ca] /5.0+ [Li] / 10.0+ [Sr] /0.8+ [Sc] /0.8+ [Y] /1.0+ [Ti] /1.0+ [Zr] /1.0+ [V] /1.0+ [Nb] /1.0+ [Co] /0.5+ [Ni] /0.5+ [Ba] /0.8+ [Be] /0.8+ [Ta] /1.0≤1 ... (2) where [X] is the content of element X (wt%)

In the present invention, the expression (1) showing the lower limit in the case where the erosion suppressing element is added in combination is expressed by a formula (1) in which the sum of (content / lower limit) of each erosion suppressing element is 1 or more (preferably 1. 2 or more)
Equation (2), which indicates the upper limit in the case where the erosion suppressing element is added in combination, shows that the sum of (content / upper limit) of each erosion suppressing element is 1 or less (preferably 0.8%).
Below). By defining the upper limit and the lower limit of the total amount of the additional elements in this manner, as in claim 1, the compound can be fixed as a compound by the erosion suppressing element to which Si and Ge which have invaded the core material from the brazing material are added in combination.
Erosion can be suppressed and prevented.

When the erosion suppressing element is added alone or in combination of more than 1.0%, if the brazing temperature is high, the core material may be melted. Therefore, when brazing at a high temperature, the content of the additional element is determined by adding the concentration of the Al alloy on the solidus line at the brazing temperature + 1.0%
It is better to stop below.

According to the first and second aspects of the present invention,
Erosion inhibiting elements are added alone or in combination to the Al alloy forming the core material, and Si and Ge that have entered the core material from the brazing material during brazing are trapped as Si compounds and Ge compounds, and these elements enter. The erosion caused by the above is suppressed and prevented. In this case, Si, G
Since e is trapped at the very surface portion of the core material from the interface between the brazing material and the core material, it is not always necessary for the entire core material to contain the erosion suppressing element. The inventions according to claims 3 and 4 have been made from such a viewpoint.

That is, the invention described in claim 3 is:
Si: 6.0-13.5% on both sides or one side of a core material formed of an Al alloy containing Mn: 0.05-2.0% (wt%, the same applies hereinafter) via an erosion suppressing layer. An erosion suppressing layer according to claim 1, wherein the erosion suppressing layer is an Al alloy brazing sheet in which a brazing material formed of an Al alloy containing Ge: 0.4 to 5.5% is laminated. Are formed of an Al alloy containing one of them.

Further, the invention described in claim 4 is an invention that
n: Si: 6.0-13.5% on both sides or one side of a core material formed of an Al alloy containing 0.05-2.0% (wt%, the same applies hereinafter) via an erosion suppressing layer. An Al alloy brazing sheet in which a brazing material formed of an Al alloy containing Ge: 0.4 to 5.5% is laminated, wherein the erosion suppressing layer is selected from the erosion suppressing elements described in claim 2. Contains one or more,
Further, it is formed of an Al alloy that satisfies the above formulas (1) and (2).

The basic structure of the Al alloy brazing sheet according to the third and fourth aspects of the present invention is as shown in FIG.
n: Both surfaces (see FIG. 2 (A)) or one surface (FIG. 2) of a core material 1A formed of an Al alloy containing 0.05 to 2.0%.
(B)) through the erosion suppressing layer 3 to form Si: 6.
A brazing material 2 formed of an Al alloy containing 0 to 13.5% or Ge: 0.4 to 5.5% is formed by lamination, and M contained in the Al alloy forming the core 1A.
n, the reasons for limiting the contents of Si or Ge contained in the Al alloy forming the brazing material 2 and the contents of the erosion suppressing elements added to the Al alloy forming the erosion suppressing layer 3 are the same as in the first and second aspects of the invention. It is. Regarding components other than the erosion suppressing element of the Al alloy forming the erosion suppressing layer 3, the erosion suppressing layer 3 is laminated by a clad or the like between the brazing material 2 and the core material 1A, and does not melt during brazing ( The melting point is not particularly limited as long as it is higher than the brazing temperature. Further, if the thickness of the erosion suppressing layer is 10 μm or more, preferably 50 μm or more, the effect of the present invention can be sufficiently exhibited, but from the viewpoint of reducing the thickness of the brazing sheet, the erosion suppressing layer has a thickness of 120 μm or less. Preferably, it is 100 μm or less.

The method for producing the Al alloy brazing sheet of the present invention is usually carried out by melting a core material and a brazing material, or each material of the core material, the erosion suppressing layer and the brazing material, and then hot rolling to a thin plate. It may be processed, laminated in the above order, clad rolled, cold rolled after annealing, and processed to a predetermined product thickness. Annealing may be performed as necessary during or after the cold rolling.

As a brazing sheet having an erosion preventing layer provided between an Al alloy core material and an Al alloy brazing material, there is one described in Japanese Patent Application Laid-Open No. 9-310139. The layer basically uses pure Al. Pure Al is liable to recrystallize during brazing, thereby preventing intrusion of Si from the brazing material, and has different functions and effects from those of the erosion suppressing layer of the present invention. It is to be.

[0022]

EXAMPLES Based on JIS A3003 Al alloy having the following components, various erosion suppressing elements were added to the alloys so as to have the contents shown in Tables 1 and 2 below.
1 alloy was melted, thinned by hot rolling, and further cold rolled and annealed to obtain a thin sheet for core material. On the other hand, Al-1
A brazing material thin plate made of a 0% Si-1.2% Mg alloy was laminated on both sides of the core material sheet, and clad and rolled. After annealing, cold rolling and annealing were performed, and FIG. A brazing sheet was obtained in which the brazing material (90 μm × 2) was laminated on both sides of the indicated core material (thickness: 420 μm). In the annealing after the cold rolling, the processing strain was completely removed, so that the brazing sheet became a completely annealed material.・ JISA3003 Al alloy component (substantially Al) Si: 0.6%, Fe: 0.7%, Mn: 1.2%, Z
n: 0.1%

[0023] The Al alloy brazing sheet is given a strain of 3% or 7% as the amount of elongation strain due to tensile processing,
Heat treatment simulating brazing conditions was performed, and the erosion depth of the core material caused by erosion was measured using an optical microscope. The reason why the above strain was applied to the Al alloy brazing sheet is that, in the conventional example (Sample No. 1 in Table 1) using the 3003 Al alloy as the core material, the erosion had a maximum value when the strain of 3 to 7% was applied. In order to take the most severe conditions. In the heat treatment, the strained Al alloy brazing sheet was heated in a vacuum using an infrared image heating furnace, kept at 590 ° C. for 2 minutes, and then cooled in the furnace. The heating rate during heating is 1 from room temperature to 550 ° C.
0 ° C./min, and 5 ° C./min up to 550-590 ° C. Although the cooling rate after the holding is not clear, it is considered to be several tens of degrees Celsius / minute.

Regarding the evaluation of the erosion resistance,
% And 7% strain imparting material, at least one of which has a core erosion depth of 50 μm from the interface between the brazing material and the core material before brazing.
m was judged as good or bad. When there is erosion of 50 μm or more, there is not much difference from the conventional case, and the cost is increased by adding alloying elements. If both the 3% and 7% strain imparting materials are less than 50 μm, thinning of the core material can be expected, and the industrial significance is significant. Tables 1 and 2 also show the measurement results of the core erosion depth of the larger of the 3% and 7% strain imparting materials. In the following description, the larger core erosion depth of the 3% and 7% strain imparting materials may be referred to as the maximum core erosion depth.

[0025]

[Table 1]

[0026]

[Table 2]

In the conventional example of Sample No. 1 in which the erosion suppressing element was not added, a maximum core material erosion depth of 80 μm was observed. It can be seen that all the erosion depths are less than 50 μm and that they have excellent erosion resistance. In addition, in the invention examples, an unrecrystallized region is observed in the core material after brazing, and the present invention is clearly different from the conventional erosion suppression technology using recrystallization.

On the other hand, in sample No. 5 in which Ca was added in excess of the range of the present invention, the measurement of the erosion depth was omitted because a large amount of coarse crystals which inhibited the mechanical properties and the like were formed in the core material. In addition, since Li is very expensive and may explode with an active metal, the addition of about 5% is limited in the embodiment, but if it exceeds 10.0% from the Al-Li binary system phase diagram, It can be seen that the coarse AlLi intermetallic compound is crystallized, and the corrosion resistance and workability deteriorate.

Further, Y, Ti, Zr, V, Nb, Co,
Samples No. 12, 16, 19, 22, 25, 29, 34, in which Ni and Ta were added in excess of the invention range, respectively.
In No. 38, the erosion depth was not measured because a coarse crystallized substance considered to deteriorate mechanical properties and corrosion resistance was formed on the core material. Further, even when the erosion suppressing element is added in combination, it is below the upper limit of the case where each individual element is individually added, but the left side value of the equation (2) exceeds 1, and excessive addition causes coarse crystallization. Things have formed.

Although samples to which Ba and Be were added were not prepared, the erosion suppressing effect was observed for Ca and Sr, which are homologous elements on the periodic table that show chemically similar behaviors. It is clear that these elements also have a similar erosion suppressing effect. Since Ba and Be have similar reaction behaviors in Sr and an Al alloy within the same genus, the upper and lower limits of these elements are specified to be equal to Sr.

[0031]

According to the present invention, a core material or an erosion suppressing layer in which a brazing material containing a predetermined amount of Si or Ge is laminated adjacent to an aluminum alloy containing a predetermined erosion suppressing element alone or in combination. Since it is formed of an alloy, S that has penetrated from the brazing material to the core material side during brazing
Since i or Ge can be precipitated and fixed as a Si compound or a Ge compound, penetration of these elements into the core material can be suppressed or prevented, and the erosion resistance is excellent.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the structure of an Al alloy brazing sheet of the present invention.

FIG. 2 is a schematic sectional view showing another structure of the Al alloy brazing sheet of the present invention.

[Explanation of symbols]

 1, 1A core material 2 brazing material 3 erosion suppression layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigenobu Namba 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Inside Kobe Research Institute, Kobe Steel Ltd. (72) Inventor Toshiki Ueda Kinuga, Moka City, Tochigi Prefecture Hill 15 Kobe Steel Works Moka Works Co., Ltd.

Claims (4)

[Claims] 1. A core material made of an Al alloy containing Mn: 0.05 to 2.0% (wt%, the same applies hereinafter), Si: 6.0 to 13.5% or Ge on both surfaces or one surface. :
An Al alloy brazing sheet in which a brazing material formed of an Al alloy containing 0.4 to 5.5% is laminated,
The core material is, in addition to Mn, Ca: 0.1 to 5.0%,
Li: 0.1 to 10.0%, Sr: 0.05 to 0.8
%, Sc: 0.05 to 0.8%, Y: 0.05 to 1.0
%, Ti: 0.17 to 1.0%, Zr: 0.3 to 1.0
%, V: 0.2 to 1.0%, Nb: 0.05 to 1.0
%, Co: 0.1-0.5%, Ni: 0.05-0.5
%, Ba: 0.05-0.8%, Be: 0.05-0.
A formed of an Al alloy containing one of 8% and Ta: 0.05 to 1.0% and having excellent erosion resistance.
1 alloy brazing sheet. 2. A core material made of an Al alloy containing Mn: 0.05 to 2.0% (wt%, the same applies hereinafter), Si: 6.0 to 13.5% or Ge on both surfaces or one surface. :
An Al alloy brazing sheet in which a brazing material formed of an Al alloy containing 0.4 to 5.5% is laminated,
The core material is, in addition to Mn, Ca, Li, Sr, Sc,
Y, Ti, Zr, V, Nb, Co, Ni, Ba, Be,
An Al alloy brazing sheet containing at least one of Ta and having an element content satisfying the following formulas (1) and (2) and having excellent erosion resistance. [Ca] /0.1+ [Li] /0.1+ [Sr] /0.05+ [Sc] /0.05+ [Y] /0.05+ [Ti] /0.17+ [Zr] /0.3+ [V] /0.2+ [Nb ] /0.05+ [Co] /0.1+ [Ni] /0.05+ [Ba] /0.05+ [Be] /0.05+ [Ta] /0.05≧1 ... (1) [Ca] /5.0+ [Li] / 10.0+ [Sr] /0.8+ [Sc] /0.8+ [Y] /1.0+ [Ti] /1.0+ [Zr] /1.0+ [V] /1.0+ [Nb] /1.0+ [Co] /0.5+ [Ni] /0.5+ [Ba] /0.8+ [Be] /0.8+ [Ta] /1.0≤1 ... (2) where [X] is the content of element X (wt%) 3. A core material formed of an Al alloy containing Mn: 0.05 to 2.0% (wt%, the same applies hereinafter), Si: 6.0 to both surfaces or one surface via an erosion suppressing layer.
An Al alloy brazing sheet in which a brazing material formed of an Al alloy containing 13.5% or Ge: 0.4 to 5.5% is laminated, wherein the erosion suppressing layer is
Ca: 0.1 to 5.0%, Li: 0.1 to 10.0%,
Sr: 0.05 to 0.8%, Sc: 0.05 to 0.8
%, Y: 0.05 to 1.0%, Ti: 0.17 to 1.0
%, Zr: 0.3-1.0%, V: 0.2-1.0%,
Nb: 0.05 to 1.0%, Co: 0.1 to 0.5%,
Ni: 0.05 to 0.5%, Ba: 0.05 to 0.8
%, Be: 0.05-0.8%, Ta: 0.05-1.
An Al alloy brazing sheet formed of an Al alloy containing one of 0% and having excellent erosion resistance. 4. A core material formed of an Al alloy containing Mn: 0.05 to 2.0% (wt%, the same applies hereinafter), Si: 6.0 to both surfaces or one surface via an erosion suppressing layer.
An Al alloy brazing sheet in which a brazing material formed of an Al alloy containing 13.5% or Ge: 0.4 to 5.5% is laminated, wherein the erosion suppressing layer is C
a, Li, Sr, Sc, Y, Ti, Zr, V, Nb, C
Excellent erosion resistance formed by an Al alloy containing at least one of o, Ni, Ba, Be, and Ta and having a content of contained elements satisfying the following formulas (1) and (2): Al alloy brazing sheet. [Ca] /0.1+ [Li] /0.1+ [Sr] /0.05+ [Sc] /0.05+ [Y] /0.05+ [Ti] /0.17+ [Zr] /0.3+ [V] /0.2+ [Nb ] /0.05+ [Co] /0.1+ [Ni] /0.05+ [Ba] /0.05+ [Be] /0.05+ [Ta] /0.05≧1 ... (1) [Ca] /5.0+ [Li] / 10.0+ [Sr] /0.8+ [Sc] /0.8+ [Y] /1.0+ [Ti] /1.0+ [Zr] /1.0+ [V] /1.0+ [Nb] /1.0+ [Co] /0.5+ [Ni] /0.5+ [Ba] /0.8+ [Be] /0.8+ [Ta] /1.0≤1 ... (2) where [X] is the content of element X (wt%)