JP2011068933A - Aluminum alloy clad material for heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy clad material for heat exchanger which has high strength after brazing, and has excellent pitting corrosion resistance and brazability. <P>SOLUTION: The aluminum alloy clad material 1a for heat exchanger comprises: a core material 2; a sacrificial material 3 formed at one face side of the core material 2; and a brazing filler metal 4 made of an Al-Si based alloy which is formed on the other face side of the core material 2. The sacrificial material 3 comprises, by mass, 0.001 to 0.01% Ca and 2.0 to 10.0% Zn, and the balance Al with inevitable impurities, and the core material 2 comprises, by mass, 0.1 to 1.5% Si, 0.3 to 2.0% Mn, 0.1 to 1.0% Cu and 0.02 to 0.30% Ti, and the balance Al with inevitable impurities. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an aluminum alloy clad material used for heat exchangers of automobiles and various industrial equipment.

  In general, an aluminum alloy clad material used for a heat exchanger for automobiles is one in which a brazing material and a sacrificial material (sacrificial anticorrosive material for the core material) are arranged on one and both sides of the core material. Currently, such aluminum alloy clad materials for heat exchangers are required to be thin so that the total plate thickness is about 0.3 mm or less while having high strength and high corrosion resistance in order to reduce the weight of automobiles. .

  The brazing material in the aluminum alloy clad material for heat exchanger is clad on the core material for brazing and joining in the case of producing a tube with the clad material when the heat exchanger is manufactured. In addition, the sacrificial material, for example, acts as a sacrificial anode material in contact with a fluid flowing inside a tube made of a clad material, and prevents pitting corrosion and crevice corrosion of the core material.

  For example, in Patent Document 1, the amounts of Zn and Mn in a sacrificial material (sacrificial anode material) are defined as Zn: 1.0 to 6.0% by mass, Mn: 0.2 to 2.0% by mass. Aluminum alloy clad material for heat exchangers with reduced corrosion current value of sacrificial material and improved corrosion resistance by controlling the particle size and distribution of Al-Mn intermetallic compound in the material (composite material in Patent Document 1) Is disclosed.

JP-A-11-61306

  However, in heat exchangers for automobiles, further weight reduction is required in order to reduce the weight, size and cost of automobiles, and aluminum alloy clad materials for heat exchangers are also reduced in weight, that is, thinner. Requests are getting stronger. Although the conventional aluminum alloy clad material for heat exchangers has improved corrosion resistance, it is not possible to use it as a heat exchanger that has not occurred so far due to thinning (tubes) (A hole penetrating from the inner surface to the outer surface) may occur. Thus, the aluminum alloy clad material for heat exchangers is required to have higher corrosion resistance in order to reduce the thickness. In addition, aluminum alloy clad materials for heat exchangers are also required to have excellent brazing properties for processing.

  Generally, in an aluminum alloy clad material for a heat exchanger, alloy elements such as Mn, Fe, Si, and Cu are added to an aluminum alloy for the purpose of increasing the strength. In such an aluminum alloy clad material for a heat exchanger, for example, as in Patent Document 1, sufficient corrosion resistance cannot be ensured by thinning only by controlling an Al—Mn intermetallic compound. In particular, when used in a situation where pitting corrosion (pitting corrosion) is formed, for example, in a radiator tube of an automobile, there is a possibility that perforation may occur in a relatively short time. In addition, it becomes necessary to control the inclusions and the production becomes difficult.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide an aluminum alloy clad material for a heat exchanger that has high strength after brazing and is excellent in pitting corrosion resistance and brazing property. .

  As means for solving the above problems, an aluminum alloy clad material for a heat exchanger according to the present invention (hereinafter referred to as “clad material” as appropriate) includes a core material and a sacrificial material formed on one surface side of the core material. And an aluminum alloy clad material for a heat exchanger comprising an Al—Si alloy brazing material formed on the other surface side of the core material, wherein the sacrificial material is Ca: 0.001 to. 01% by mass, Zn: 2.0-10.0% by mass, the balance is made of Al and inevitable impurities, and the core material is Si: 0.1-1.5% by mass, Mn: 0.00. It contains 3 to 2.0 mass%, Cu: 0.1 to 1.0 mass%, Ti: 0.02 to 0.30 mass%, and the balance is made of Al and inevitable impurities.

  According to such a configuration, the sacrificial material contains a predetermined amount of Ca and Zn, and the core material contains a predetermined amount of Si, Mn, Cu, and Ti, so that the pitting corrosion resistance of the aluminum alloy clad material for heat exchangers, The brazing performance is improved and the strength after brazing is increased.

In the aluminum alloy clad material for a heat exchanger according to the present invention, the sacrificial material further contains at least one of Mn: 0.3 to 2.0% by mass and Si: 0.1 to 1.0% by mass. It is characterized by.
According to such a configuration, the sacrificial material further contains a predetermined amount of at least one of Mn and Si, whereby the strength of the sacrificial material is improved and pitting corrosion resistance is maintained.

The aluminum alloy clad material for a heat exchanger according to the present invention is characterized in that the sacrificial material further contains Cr: 0.01 to 0.3% by mass.
According to such a configuration, the sacrificial material further contains a predetermined amount of Cr, thereby improving the pitting corrosion resistance of the sacrificial material.

The aluminum alloy clad material for a heat exchanger according to the present invention is characterized in that the core material further contains Mg: 0.05 to 0.7 mass%.
According to such a configuration, when the core material further contains a predetermined amount of Mg, an Mg ₂ Si compound is formed, the strength of the core material is improved, and brazing properties are maintained.

The aluminum alloy clad material for a heat exchanger according to the present invention is characterized in that an intermediate material made of an aluminum alloy not containing Mg is provided between the core material and the brazing material.
According to such a configuration, by providing the intermediate material between the core material and the brazing material, when Mg is contained in the core material, heat diffusion of Mg into the brazing material is suppressed. Therefore, brazability is maintained.

  According to the aluminum alloy clad material for a heat exchanger according to the present invention, the strength after brazing is increased, and the pitting corrosion resistance and the brazing property can be improved.

(A), (b) is sectional drawing which shows the structure of the aluminum alloy clad material for heat exchangers which concerns on this invention.

An embodiment of an aluminum alloy clad material for a heat exchanger according to the present invention (hereinafter referred to as a clad material as appropriate) will be described with reference to the drawings.
As shown in FIG. 1A, a clad material 1a is a three-layer structure in which a sacrificial material 3 is clad on one surface side of a core material 2 and a brazing material 4 is clad on the other surface side of the core material 2. Basic configuration. The clad material only needs to have the sacrificial material 3 formed on the outermost surface on one side of the core material and the brazing material 4 formed on the outermost surface on the other surface side. As shown in FIG. A four-layer clad material 1b in which a sacrificial material 3 is formed on one surface side 2 and an intermediate material 5 and a brazing material 4 are formed on the other surface side of the core material 2 may be used. Further, although not shown, a clad material having five or more layers in which the number of layers of the sacrificial material 3, the brazing material 4, and the intermediate material 5 is increased may be used.

  Below, the significance of the alloy components in the core material 2, the sacrificial material 3, the brazing material 4 and the intermediate material 5 constituting the clad materials 1a and 1b and the reason for limiting the numerical values will be described.

《Core material》
Core material 2 is Si: 0.1-1.5 mass%, Mn: 0.3-2.0 mass%, Cu: 0.1-1.0 mass%, Ti: 0.02-0.30 It contains mass%, and the balance consists of Al and inevitable impurities.

<Si: 0.1 to 1.5% by mass>
Si has an effect of improving the strength of the core material 2. When the core material 2 contains Mg forms a Mg 2 _Si, the effect of further improving the strength. However, when the Si content is less than 0.1% by mass, the strength is not improved, and the strength after brazing becomes insufficient. On the other hand, when it contains exceeding 1.5 mass%, the melting | fusing point will fall, and the core material 2 will fuse | melt at the time of brazing. Therefore, the Si content is 0.1 to 1.5 mass%. In addition, Preferably it is 0.5-1.2 mass%.

<Mn: 0.3 to 2.0% by mass>
Mn has the effect of improving the strength of the core material 2. Mn dissolves in the core material 2 and improves the strength of the core material 2. However, if the Mn content is less than 0.3% by mass, the strength is not improved, and the strength after brazing becomes insufficient. On the other hand, if the content exceeds 2.0% by mass, coarse precipitates are formed, the workability is reduced and cracks are generated, and when pitting corrosion reaches the core material 2, it acts as a cathode site, It promotes food (corrosion). Therefore, the Mn content is set to 0.3 to 2.0 mass%. In addition, Preferably it is 0.5-1.2 mass%.

<Cu: 0.1 to 1.0% by mass>
Cu has the effect of improving the strength of the core material 2. However, when the Cu content is less than 0.1% by mass, the potential difference of the core material 2 with respect to the sacrificial material 3 is not sufficiently ensured, and when pitting corrosion reaches the core material 2, pitting corrosion (corrosion) develops. On the other hand, when it contains exceeding 1.0 mass%, the melting | fusing point will fall, and the core material 2 will fuse | melt at the time of brazing. Therefore, the Cu content is set to 0.1 to 1.0% by mass. In addition, Preferably it is 0.6-1.0 mass%.

<Ti: 0.02-0.30 mass%>
Ti is distributed in a layered manner in the core material 2 and has an effect of improving the corrosion resistance because the corrosion form is layered. However, when the Ti content is less than 0.02% by mass, the effect of stratifying the corrosion form is not exhibited. On the other hand, if the content exceeds 0.30% by mass, a coarse Al-Ti intermetallic compound is produced, which causes cracks during molding and processing. Therefore, the Ti content is 0.02 to 0.30 mass%. In addition, Preferably it is 0.02-0.20 mass%.

<Balance: Al and inevitable impurities>
The remainder of the core material 2 is made of Al and inevitable impurities. Inevitable impurities include, for example, Zr, B, and Fe. Even if these inevitable impurities are contained up to 0.5% by mass in total, the effect of the present invention is not disturbed. Therefore, the total content of inevitable impurities is allowed up to 0.5% by mass.

  In addition to the above composition, the core material 2 preferably further contains Mg: 0.05 to 0.7% by mass in order to improve the strength.

<Mg: 0.05 to 0.7% by mass>
Mg has the effect of forming Mg ₂ Si and improving the strength of the core material 2. However, when the Mg content is less than 0.05% by mass, the strength is not improved, and the strength after brazing becomes insufficient. On the other hand, if the content exceeds 0.7% by mass, the flux component and Mg react with each other during brazing using a general flux (Nocolok method), and the brazing property tends to be lowered. Therefore, the content of Mg is preferably 0.05 to 0.7% by mass. In addition, More preferably, it is 0.1-0.5 mass%.

《Sacrificial material》
The sacrificial material 3 contains Ca: 0.001 to 0.01% by mass, Zn: 2.0 to 10.0% by mass, and the balance is made of Al and inevitable impurities.

<Ca: 0.001 to 0.01% by mass>
Ca has an effect of suppressing the pH reduction of the pitting corrosion starting point generated in the sacrificial material 3 and suppressing the progress of pitting corrosion. However, when the Ca content is less than 0.001% by mass, sufficient pitting corrosion resistance is not exhibited. On the other hand, if the Ca content exceeds 0.01% by mass, cracking occurs during rolling. Therefore, the Ca content is set to 0.001 to 0.01% by mass. In addition, Preferably it is 0.005-0.01 mass%.

<Zn: 2.0 to 10.0% by mass>
Zn has an effect of lowering the potential of the sacrificial material 3 which is a sacrificial anode material, improving the sacrificial anode effect on the core material 2, and suppressing the occurrence of pitting corrosion on the core material 2. However, if the Zn content is less than 2.0% by mass, sufficient sacrificial anode effect cannot be obtained, intergranular corrosion also occurs, and pitting corrosion resistance (corrosion resistance) decreases. On the other hand, if the Zn content exceeds 10.0% by mass, not only cracking occurs during clad rolling, but also self-corrosion properties increase. Therefore, the Zn content is set to 2.0 to 10.0% by mass. In addition, Preferably it is 4.0-9.0 mass%.

<Balance: Al and inevitable impurities>
The remaining part of the sacrificial material 3 is made of Al and inevitable impurities. Inevitable impurities include, for example, Ti, Zr, B, and Fe. Even if these inevitable impurities are contained up to 0.5% by mass in total, the effect of the present invention is not disturbed. Therefore, the total content of inevitable impurities is allowed up to 0.5% by mass.

  The sacrificial material 3 may further contain at least one of Mn: 0.3 to 2.0 mass% and Si: 0.1 to 1.0 mass% in addition to the above composition.

<Mn: 0.3 to 2.0% by mass>
Mn has the effect of improving the strength of the sacrificial material 3. Mn dissolves in the sacrificial material 3 and improves the strength of the sacrificial material 3. However, if the Mn content is less than 0.3% by mass, the strength is not improved and cracking is likely to occur. On the other hand, when the content exceeds 2.0% by mass, coarse precipitates are formed, behave as cathode sites in the sacrificial material 3, and facilitate pitting corrosion (corrosion). Therefore, the content of Mn is preferably 0.3 to 2.0% by mass. In addition, More preferably, it is 0.5-1.2 mass%.

<Si: 0.1 to 1.0% by mass>
Si has the effect of improving the strength of the sacrificial material 3. However, if the Si content is less than 0.1% by mass, the strength is not improved and cracking is likely to occur. On the other hand, when the Si content is higher, the strength of the sacrificial material 3 is improved. However, if the Si content exceeds 1.0% by mass, coarse precipitates are formed and the intergranular corrosion sensitivity is likely to increase. . Therefore, the content of Si is preferably 0.1 to 1.0% by mass. In addition, More preferably, it is 0.1-0.7 mass%.

  In addition to the said composition, the sacrificial material 3 may further contain Cr: 0.01-0.3 mass%.

<Cr: 0.01 to 0.3% by mass>
Cr forms fine precipitates with Al in the sacrificial material 3 and behaves as fine cathode sites. Increases the number of cathodic sites of pitting corrosion points finely dispersed by adding Cr and suppresses the progress of corrosion in the depth direction. However, when the Cr content is less than 0.01% by mass, the dispersion of the cathode sites is not sufficient, and the effect is hardly exhibited. On the other hand, when the Cr content exceeds 0.3% by mass, coarse precipitates are formed, and the cathode sites are not sufficiently dispersed, and the pitting corrosion resistance is liable to be lowered. Therefore, the Cr content is preferably 0.01 to 0.3% by mass. In addition, More preferably, it is 0.05-0.2 mass%.

《Brazing material》
The brazing material 4 is made of an Al—Si based alloy, and examples of the Al—Si based alloy include general JIS alloys such as 4343 alloy and 4045 alloy. Here, the Al—Si based alloy includes an alloy containing Zn in addition to Si. That is, examples of the Al—Si based alloy include an Al—Si based alloy and an Al—Si—Zn based alloy. In addition to Si and Zn, for example, Fe, Cu, Mn, Mg, and the like may be contained.

  The Al—Si based alloy contains, for example, Ti, Zr, B, and Fe as inevitable impurities. Such inevitable impurities are, for example, Ti 0.05 mass% or less, Zr 0.2 mass% or less, B 0.1 mass% or less, Fe 0.2 mass% or less (both 0 mass) %) Does not hinder the effects of the present invention. Therefore, the inclusion of such inevitable impurities is allowed. In addition, in the brazing material 4, the content of such inevitable impurities can be tolerated up to 0.4% by mass.

  As shown in FIG. 1B, the clad material 1b according to the present invention includes the core material 2, the sacrificial material 3 and the brazing material 4, and does not contain Mg between the core material 2 and the brazing material 4. It is preferable to provide an intermediate material 5 made of an aluminum alloy. By providing such an intermediate material 5 between the core material 2 and the brazing material 4, when the core material 2 contains Mg, the Mg contained in the core material 2 thermally diffuses into the brazing material 4. It has the effect of preventing the deterioration of brazing.

《Intermediate material》
The intermediate material 5 is made of an aluminum alloy that does not contain Mg, and is preferably pure Al or a JIS-defined 3000 series alloy (for example, 3003 alloy). Moreover, Si, Mn, Cu, Ti, etc. can be added to the aluminum alloy which does not contain Mg as needed in order to improve the strength and secure the potential difference of the brazing material 4. Examples of the composition include Al-1 mass% Si-1 mass% Cu-1.6 mass% Mn. Such an intermediate material 5 can prevent thermal diffusion of the core material 2 to the brazing material 4 of Mg. Further, the additive element can keep the potential more noble than the brazing material 4 and can prevent pitting corrosion (corrosion) of the core material 2.

  An aluminum alloy not containing Mg contains, for example, Zr, B, and Fe as inevitable impurities. Such inevitable impurities are, for example, in the range of Zr of 0.2% by mass or less, B of 0.1% by mass or less, Fe of 0.2% by mass or less (all not including 0% by mass), etc. Even if it contains, the effect of this invention is not disturbed. Therefore, the inclusion of such inevitable impurities is allowed. In addition, in the intermediate material 5, content of such inevitable impurities can be tolerated up to 0.4% by mass.

The clad material 1a (1b) according to the present invention can be manufactured, for example, by the following manufacturing method.
First, an aluminum alloy for the core material, an aluminum alloy for the sacrificial material, and an aluminum alloy for the brazing material are melted, ingot, and cast by continuous casting to produce an ingot, and face grinding and homogenization heat treatment are performed as necessary. The core ingot, the sacrificial ingot and the brazing ingot are produced. Each ingot is hot-rolled to a desired thickness or mechanically sliced to a desired thickness to form a core member, a sacrificial member, and a brazing member. When providing the intermediate material, the intermediate material member is manufactured in the same manner as described above.

  Next, a sacrificial material member is superposed on one surface side of the core member, and a brazing material member (intermediate material member if necessary) is superposed on the other surface side, and heat treatment (reheating) is performed on the superposed material. And crimping by hot rolling. Thereafter, cold rolling and intermediate annealing are performed, and further cold rolling is performed. After that, finish annealing may be performed.

  In manufacturing the clad material 1a (1b), other processes such as a distortion correction process may be included before and after each process as long as the process is not adversely affected.

  Next, an aluminum alloy clad material for a heat exchanger will be specifically described by comparing an example that satisfies the requirements of the present invention with a comparative example that does not satisfy the requirement.

<Manufacture of test materials>
An aluminum alloy for a sacrificial material having a chemical composition as shown in Table 1 was melted and formed by continuous casting, and cast at a casting temperature of 700 to 760 ° C. to produce an ingot, and then 550 ° C. (6 hours) The material for sacrificial material was manufactured by hot rolling at 400 ° C. or higher.

  Further, an aluminum alloy for a core material having a chemical composition as shown in Table 2 was melted and formed by continuous casting, and cast at a casting temperature of 700 ° C. to produce an ingot, and then 530 ° C. (6 hours) In the following, a homogenization treatment was performed, followed by hot rolling to produce a core member.

  Further, an intermediate material member having the chemical composition shown in Table 4 was produced in the same manner as the core material member.

  And the aluminum alloy for brazing | wax materials of Al-11 mass% Si alloy was cast on general conditions, and after homogenizing, the member for brazing | wax materials was manufactured by hot-rolling.

  A sacrificial material member is stacked on one surface side of the manufactured core material member, a brazing material member is stacked on the other surface side, hot rolling is performed at 400 to 550 ° C., and then cold rolling and intermediate annealing are performed. Cold-rolled, No. shown in Table 3 1 to 24 clad materials were produced. The clad material thickness was 0.25 mm, the sacrificial material thickness was 0.03 mm, and the core material thickness was 0.19 mm.

  Similarly, a sacrificial material member is stacked on one surface side of the core material member, a brazing material member and an intermediate material member are stacked on the other surface side, hot rolled at 400 to 550 ° C., and then cold rolled. No. shown in Table 5 A clad material containing 25-30 intermediate materials was produced. The clad material thickness was 0.30 mm, the sacrificial material thickness was 0.03 mm, the core material thickness was 0.19 mm, and the intermediate material thickness was 0.05 mm.

The clad material thus produced was evaluated for tensile strength after brazing (strength after brazing), brazing property and pitting corrosion resistance by the following procedure.
<Tensile strength after brazing>
The tensile strength after brazing was evaluated based on the strength to break by a tensile test. After heating at 600 ° C. for 3 minutes in an N ₂ atmosphere (after brazing), a test piece was cut out in a direction parallel to the rolling direction, and a tensile test was performed. The tensile strength after brazing was evaluated as poor (XX) when the tensile strength was less than 160 MPa, slightly poor (X) when 160 MPa or more and less than 180 MPa, and good (◯) when 180 MPa or more. The results are shown in Table 3 and Table 5.

<Brassability>
Brazeability is evaluated by the clearance filling test method (see Aluminum Brazing Handbook (published in January 1992), Light Metal Structural Welding Association, “Clearance Filling Test Method” on page 133). Measured and evaluated as brazeability. A clad material was used for the upper plate, an aluminum material (3003 alloy, plate thickness was 1.0 mm) for the lower plate, and a 1.0 mmφ spacer was used. Fluoride-based flux was applied to the brazing filler metal surface of the upper clad material at a rate of 5 g / m ² and a brazing test was held at 600 ° C. for 5 minutes in a nitrogen atmosphere. A clearance filling length of 20 mm or less was evaluated as defective (×), and a clearance filling length exceeding 20 mm was evaluated as good (◯). The results are shown in Table 3 and Table 5.

<Pitting corrosion resistance>
Evaluation of pitting corrosion resistance was performed by measuring the maximum pitting corrosion depth. The maximum pitting depth was measured as follows. The clad material was cut out with dimensions of 50 mm in length and 50 mm in width, and OY water (Cl ⁻ : 195 mass ppm, SO ₄ ²⁻ : 60 mass ppm, Cu ²⁺ : 1 mass ppm, Fe ³⁺ : 30 as a cooling water simulation liquid). Immersion in mass ppm, pH: 3.0) and hold at 88 ° C for 8 hours (including heating time from room temperature to 88 ° C), then hold at room temperature for 16 hours (natural cooling time from 88 ° C to room temperature) The immersion test of the cycle to be included was performed for one month, and the corrosion depth (maximum pitting corrosion depth) on the sacrificial material side after the test was measured.

  The maximum pitting depth is measured by removing the corrosion products generated on the surface of the sample after the immersion test, and then measuring the pitting depth generated in each clad material at 50 points / sheet by the focal depth method. Of the 50 points measured, the deepest pitting corrosion was taken as the maximum pitting corrosion depth. When the maximum pitting corrosion depth was 40 μm or less, pitting corrosion resistance was good, and when it exceeded 40 μm, pitting corrosion resistance was evaluated as poor. The results are shown in Table 3 and Table 5.

  As shown in Table 3, since Examples (Nos. 1 to 16) satisfy the requirements of the present invention, the strength after brazing was high, and the brazing property and pitting corrosion resistance were excellent.

  On the other hand, in Comparative Example (No. 17), cracks occurred because there was little Mn in the sacrificial material, and because there were few Si, Mn, and Mg in the core material, the strength after brazing was low, and fracture occurred at less than 160 MPa. did. Moreover, since there was much Cu in a core material, the core material melted and could not be brazed. Furthermore, pitting corrosion progressed and pitting corrosion resistance was inferior because Ca and Zn in the sacrificial material were small and Cr was large.

  In the comparative example (No. 18), cracks occurred because there was little Mn in the sacrificial material, and there was much Mn and Ti in the core material, and there was little Mg, so the strength after brazing was low, and fracture occurred at less than 160 MPa. did. Moreover, since there was much Cu in a core material, the core material melted and could not be brazed. Furthermore, pitting corrosion progressed and pitting corrosion resistance was inferior because Ca and Zn in the sacrificial material were low, Cr was high, and Mn was high in the core material.

  In the comparative example (No. 19), cracks occur because there is a lot of Ca in the sacrificial material and a small amount of Si, and since the core material does not contain Mg and has little Mn, the strength after brazing is low, and 160 MPa. The fracture occurred at less than 180 MPa. Moreover, since there was much Si in a core material, brazability was inferior. Furthermore, since the sacrificial material does not contain Zn, the amount of Mn is large, and the amount of Cu and Ti in the core material is small, the pitting corrosion progresses and the pitting corrosion resistance is poor.

  In the comparative example (No. 20), cracks occurred because there was a lot of Ca in the sacrificial material and a small amount of Si, and because there was a lot of Mn in the core material, the strength after brazing was low, and fracture occurred at less than 160 MPa. Moreover, since there was much Cu and Mg in a core material, the core material melt | dissolved and it could not be brazed. Furthermore, since the sacrificial material does not contain Zn, the amount of Mn is large, and the amount of Mn in the core material is large, pitting corrosion progresses and pitting corrosion resistance is poor.

  In Comparative Example (No. 21), cracks occur because there is little Mn in the sacrificial material, and since the core material does not contain Mg and there is also little Mn, the strength after brazing is low, 160 MPa or more and less than 180 MPa. It broke. Moreover, since there was much Si in a core material, brazability was inferior. Furthermore, pitting corrosion progressed and pitting corrosion resistance was inferior because Zn in the sacrificial material was small, Si and Cr were large, and Cu and Ti in the core material were small.

  In the comparative example (No. 22), cracks occurred because there was little Mn in the sacrificial material, and there was much Mn and Ti in the core material, and there was little Mg, so the strength after brazing was low, and fracture occurred at less than 160 MPa. did. Moreover, since there was much Cu in a core material, the core material melted and could not be brazed. Furthermore, since the Zn in the sacrificial material is small, the amount of Si and Cr is large, and the amount of Mn in the core material is large, pitting corrosion progresses and pitting corrosion resistance is inferior.

  In the comparative example (No. 23), cracks occurred due to the large amount of Ca and Zn in the sacrificial material, and the strength after brazing was low due to the small amount of Si, Mn, and Mg in the core material. did. Moreover, since there was much Cu in a core material, the core material melted and could not be brazed. Furthermore, since there were many Zn and Si in a sacrificial material, and there were few Cr, pitting corrosion progressed and pitting corrosion resistance was inferior.

  In the comparative example (No. 24), cracks occurred due to the large amount of Ca and Zn in the sacrificial material, and the strength after brazing was low because of the large amount of Mn in the core material, and fractured at less than 160 MPa. Moreover, since there was much Cu and Mg in a core material, the core material melt | dissolved and it could not be brazed. Furthermore, since there were a lot of Zn and Si in the sacrificial material, a small amount of Cr, and a large amount of Mn in the core material, pitting corrosion progressed and pitting corrosion resistance was poor.

  As shown in Table 5, since the examples (Nos. 25 to 28) satisfy the requirements of the present invention, the strength after brazing was high, and the brazing property and pitting corrosion resistance were excellent.

  On the other hand, in Comparative Example (No. 29), cracks occurred because there was little Mn in the sacrificial material, and because there were few Si, Mn and Mg in the core material, the strength after brazing was low, and fracture occurred at less than 160 MPa. did. Moreover, since there was much Cu in a core material, the core material melted and could not be brazed. Furthermore, pitting corrosion progressed and pitting corrosion resistance was inferior because Ca and Zn in the sacrificial material were small and Cr was large.

  In the comparative example (No. 30), cracks occurred due to the large amount of Ca and Zn in the sacrificial material, and the strength after brazing was low due to the small amount of Si, Mn and Mg in the core material, and fractured at less than 160 MPa. did. Moreover, since there was much Cu in a core material, the core material melted and could not be brazed. Furthermore, since there were many Zn and Si in a sacrificial material, and there were few Cr, pitting corrosion progressed and pitting corrosion resistance was inferior.

1a, 1b Clad material 2 Core material 3 Sacrificial material 4 Brazing material 5 Intermediate material

Claims (5)

An aluminum alloy clad material for a heat exchanger, comprising: a core material; a sacrificial material formed on one surface side of the core material; and a brazing material made of an Al-Si alloy formed on the other surface side of the core material. There,
The sacrificial material contains Ca: 0.001 to 0.01% by mass, Zn: 2.0 to 10.0% by mass, and the balance is made of Al and inevitable impurities.
The core material is Si: 0.1 to 1.5 mass%, Mn: 0.3 to 2.0 mass%, Cu: 0.1 to 1.0 mass%, Ti: 0.02 to 0.30. An aluminum alloy clad material for a heat exchanger, comprising: mass%, the balance being made of Al and inevitable impurities.   2. The heat exchanger according to claim 1, wherein the sacrificial material further contains at least one of Mn: 0.3 to 2.0 mass% and Si: 0.1 to 1.0 mass%. Aluminum alloy clad material.   The said sacrificial material contains Cr: 0.01-0.3 mass% further, The aluminum alloy clad material for heat exchangers of Claim 1 or Claim 2 characterized by the above-mentioned.   The aluminum alloy clad material for a heat exchanger according to any one of claims 1 to 3, wherein the core material further contains Mg: 0.05 to 0.7 mass%.   The aluminum alloy for a heat exchanger according to any one of claims 1 to 4, wherein an intermediate material made of an aluminum alloy not containing Mg is provided between the core material and the brazing material. Clad material.

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