ALUMINUM ALLOY HEAT EXCHANGER FOR EXHAUST GAS RECIRCULATION SYSTEM

Abstract

An aluminum alloy heat exchanger for an exhaust gas recirculation system, which is a heat exchanger installed in an exhaust gas recirculation system of an internal combustion engine to cool the exhaust gas comprises a tube provided with a sacrificial anticorrosion material on a side along which the exhaust gas passes, and a fin brazed to the surface side of the sacrificial anticorrosion material of the tube, the fin having a pitting potential higher than the pitting potential of the surface of the sacrificial anticorrosion material of the tube. According to the disclosure, an aluminum alloy heat exchanger for an exhaust gas recirculation system having a long service life with effective function of the sacrificial anticorrosion even under an acidic environment in which an oxide film is weakened as a whole and pitting corrosion is unlikely to occur can be provided.

Claims

1. An aluminum alloy heat exchanger for an exhaust gas recirculation system, which is a heat exchanger installed in an exhaust gas recirculation system of an internal combustion engine to cool the exhaust gas, the heat exchanger comprising: a tube provided with a sacrificial anticorrosion material on a side along which the exhaust gas passes, and a fin brazed to a sacrificial anticorrosion material surface side of the tube, the fin having a pitting potential higher than a pitting potential of a sacrificial anticorrosion material surface of the tube.

2. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 1, wherein the condensed water of the exhaust gas has a pH of less than 3 and a chloride ion concentration of less than 100 ppm.

3. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 1, wherein the heat exchanger is obtained by brazing: a tube material comprising at least a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.05 mass % or more and 3.00 mass % or less of Cu, and 0.40 mass % or more and 2.00 mass % or less of Mn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of Cr, 0.05 mass % or more and 0.30 mass % or less of Zr, 0.05 mass % or more and 0.30 mass % or less of Ti, and 0.05 mass % or more and 0.30 mass % or less of V, with the balance being Al and unavoidable impurities, and a sacrificial anticorrosion material made of aluminum alloy comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.50 mass % or more and 6.00 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 2.00 mass % or less of Mn, 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of In, 0.05 mass % or more and 0.30 mass % or less of Sn, 0.05 mass % or more and 0.30 mass % or less of Ti, 0.05 mass % or more and 0.30 mass % or less of V, 0.05 mass % or more and 0.30 mass % or less of Cr, and 0.05 mass % or more and 0.30 mass % or less of Zr, with the balance being Al and unavoidable impurities, clad on an exhaust gas passage side surface of the core material; and a fin material comprising a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.40 mass % or more and 2.00 mass % or less of Mn, and 0.00 mass % or more and 0.05 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg and 0.10 mass % or more and 1.00 mass % or less of Fe, with the balance being Al and unavoidable impurities.

4. (canceled)

5. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 1, wherein the heat exchanger is obtained by brazing: a tube material comprising at least a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.05 mass % or more and 3.00 mass % or less of Cu, and 0.40 mass % or more and 2.00 mass % or less of Mn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of Cr, 0.05 mass % or more and 0.30 mass % or less of Zr, 0.05 mass % or more and 0.30 mass % or less of Ti, and 0.05 mass % or more and 0.30 mass % or less of V, with the balance being Al and unavoidable impurities, and a sacrificial anticorrosion material made of aluminum alloy comprising 3.00 mass % or more and 13.00 mass % or less of Si, and 0.50 mass % or more and 6.00 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 2.00 mass % or less of Mn, 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of In, 0.05 mass % or more and 0.30 mass % or less of Sn, 0.05 mass % or more and 0.30 mass % or less of Ti, 0.05 mass % or more and 0.30 mass % or less of V, 0.05 mass % or more and 0.30 mass % or less of Cr, and 0.05 mass % or more and 0.30 mass % or less of Zr, with the balance being Al and unavoidable impurities, clad on an exhaust gas passage side surface of the core material; and a fin material comprising a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.40 mass % or more and 2.00 mass % or less of Mn, and 0.00 mass % or more and 0.05 mass % or less of Zn, with the balance being Al and unavoidable impurities, and a first brazing material clad on one surface of the core material and a second brazing material clad on another surface of the core material, made of aluminum alloy comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.00 mass % or more and 0.05 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg and 0.10 mass % or more and 1.00 mass % or less of Fe, with the balance being Al and unavoidable impurities.

6. (canceled)

7. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 3, wherein the tube material comprises a brazing material comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.00 mass % or more and 0.05 mass % or less of Zn, with the balance being Al and unavoidable impurities, clad on a surface opposite to the surface clad with the sacrificial anticorrosion material of the tube material.

8-9. (canceled)

10. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 2, wherein the heat exchanger is obtained by brazing: a tube material comprising at least a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.05 mass % or more and 3.00 mass % or less of Cu, and 0.40 mass % or more and 2.00 mass % or less of Mn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of Cr, 0.05 mass % or more and 0.30 mass % or less of Zr, 0.05 mass % or more and 0.30 mass % or less of Ti, and 0.05 mass % or more and 0.30 mass % or less of V, with the balance being Al and unavoidable impurities, and a sacrificial anticorrosion material made of aluminum alloy comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.50 mass % or more and 6.00 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 2.00 mass % or less of Mn, 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of In, 0.05 mass % or more and 0.30 mass % or less of Sn, 0.05 mass % or more and 0.30 mass % or less of Ti, 0.05 mass % or more and 0.30 mass % or less of V, 0.05 mass % or more and 0.30 mass % or less of Cr, and 0.05 mass % or more and 0.30 mass % or less of Zr, with the balance being Al and unavoidable impurities, clad on an exhaust gas passage side surface of the core material; and a fin material comprising a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.40 mass % or more and 2.00 mass % or less of Mn, and 0.00 mass % or more and 0.05 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg and 0.10 mass % or more and 1.00 mass % or less of Fe, with the balance being Al and unavoidable impurities.

11. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 2, wherein the heat exchanger is obtained by brazing: a tube material comprising at least a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.05 mass % or more and 3.00 mass % or less of Cu, and 0.40 mass % or more and 2.00 mass % or less of Mn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of Cr, 0.05 mass % or more and 0.30 mass % or less of Zr, 0.05 mass % or more and 0.30 mass % or less of Ti, and 0.05 mass % or more and 0.30 mass % or less of V, with the balance being Al and unavoidable impurities, and a sacrificial anticorrosion material made of aluminum alloy comprising 3.00 mass % or more and 13.00 mass % or less of Si, and 0.50 mass % or more and 6.00 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 2.00 mass % or less of Mn, 0.05 mass % or more and 0.50 mass % or less of Mg, 0.10 mass % or more and 1.00 mass % or less of Fe, 0.05 mass % or more and 1.00 mass % or less of Ni, 0.05 mass % or more and 0.30 mass % or less of In, 0.05 mass % or more and 0.30 mass % or less of Sn, 0.05 mass % or more and 0.30 mass % or less of Ti, 0.05 mass % or more and 0.30 mass % or less of V, 0.05 mass % or more and 0.30 mass % or less of Cr, and 0.05 mass % or more and 0.30 mass % or less of Zr, with the balance being Al and unavoidable impurities, clad on an exhaust gas passage side surface of the core material; and a fin material comprising a core material made of aluminum alloy comprising 0.05 mass % or more and 1.50 mass % or less of Si, 0.40 mass % or more and 2.00 mass % or less of Mn, and 0.00 mass % or more and 0.05 mass % or less of Zn, with the balance being Al and unavoidable impurities, and a first brazing material clad on one surface of the core material and a second brazing material clad on another surface of the core material, made of aluminum alloy comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.00 mass % or more and 0.05 mass % or less of Zn, and optionally one or more selected from the group consisting of 0.05 mass % or more and 0.50 mass % or less of Mg and 0.10 mass % or more and 1.00 mass % or less of Fe, with the balance being Al and unavoidable impurities.

12. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 5, wherein the tube material comprises a brazing material comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.00 mass % or more and 0.05 mass % or less of Zn, with the balance being Al and unavoidable impurities, clad on a surface opposite to the surface clad with the sacrificial anticorrosion material of the tube material.

13. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 7, wherein the tube material comprises a brazing material comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.00 mass % or more and 0.05 mass % or less of Zn, with the balance being Al and unavoidable impurities, clad on a surface opposite to the surface clad with the sacrificial anticorrosion material of the tube material.

14. The aluminum alloy heat exchanger for an exhaust gas recirculation system according to claim 11, wherein the tube material comprises a brazing material comprising 3.00 mass % or more and 13.00 mass % or less of Si and 0.00 mass % or more and 0.05 mass % or less of Zn, with the balance being Al and unavoidable impurities, clad on a surface opposite to the surface clad with the sacrificial anticorrosion material of the tube material.

Description

EXAMPLES

Examples and Comparative Examples

<Preparation of Tube Material>

[0078] Each of aluminum alloy ingots for the core material, the sacrificial anticorrosion material and the brazing material of the tube material having a composition shown in Tables 1 to 3 was cast by semi-continuous casting, which was machine-finished and subjected to homogenization treatment at 520 C. for 6 hours.

[0079] Subsequently, based on the combination shown in Table 5, the ingot for the sacrificial anticorrosion material was overlapped on one surface of the ingot for the core material. When a brazing material is clad, an ingot for the brazing material is overlapped on the opposite surface. Thereby overlapped ingots were prepared. The thickness of the sacrificial anticorrosion material and thickness of the brazing material were adjusted such that each had a clad ratio of 10%.

[0080] Subsequently, the overlapped ingots were heat treated up to 520 C. before the step of hot rolling, and immediately hot rolled to make a two-layer or three-layer clad plate having a thickness of 3.5 mm. Subsequently, the clad plate obtained was cold rolled to a thickness of 0.30 mm, and then annealed at 500 C. for 2 hours. Through the steps described above, a two-layer or three-layer tube material having a whole thickness of 0.30 mm and a clad ratio of the sacrificial anticorrosion material layer of 10% was prepared.

<Preparation of Fin Material>

[0081] Each of aluminum alloy ingots for the brazing material and the core material for a fin material shown in Table 3 and Table 4 was cast by semi-continuous casting, which was machine-finished and subjected to homogenization treatment at 520 C. for 6 hours.

[0082] Subsequently, as shown in Table 5 to Table 7, from an ingot for the core material as it is, or based on the combination shown in Table 5 to Table 7, an ingot for the brazing material was overlapped on both surfaces of the ingot for the core material to prepare an ingot. The thickness of the brazing material was adjusted such that each had a clad ratio of 10%.

[0083] Subsequently, when the fin material is a clad material, the overlapped ingots were heat treated up to 520 C. before the step of hot rolling, and immediately hot rolled to make a three-layer clad plate having a thickness of 3.5 mm. Further, cold rolling and final annealing at 390 to 450 C. for 4 hours were performed to prepare a three-layer fin material having a thickness of about 0.1 mm.

[0084] When the fin material is a bare material, the ingot for core material was heat treated up to 520 C. before the step of hot rolling, and immediately hot rolled to make a plate having a thickness of 3.5 mm. Further, cold rolling and final annealing at 390 to 450 C. for 4 hours were performed to prepare a one-layer fin material having a thickness of about 0.1 mm.

(Measurement of Tensile Strength After Brazing Heating)

[0085] A single sample of the tube material and a single sample of the fin material thus prepared were subjected to brazing heating at 600 C. for 3 minutes in a nitrogen atmosphere. After brazing heating, the sample was cooled to room temperature for use in a tensile test in accordance with JIS Z2241 under conditions with a tensile speed of 10 mm/minute and a gauge length of 50 mm. The tensile strength was determined from the stress-strain curve obtained.

<Preparation of Test Sampler for Evaluation>

[0086] The fin material obtained above was slit into a width of 16 mm, corrugated, and formed into a fin shape for a heat exchanger.

[0087] Subsequently, the tube material was cut into a width of 16 mm and a length of 70 mm to prepare a test piece of tube material, and a KF-AlF-based flux (KAlF.sub.4 or the like) powder was applied to the surface of the sacrificial anticorrosion material of the test piece of tube material.

[0088] Subsequently, the corrugated fin material was sandwiched between two test pieces of the tube material, such that the surface of the sacrificial anticorrosion was on the fin side, and brazing heating was performed at 600 C. for 3 minutes in a nitrogen atmosphere. After brazing heating, the temperature was cooled to room temperature, and a test sample for evaluation was prepared.

(Measurement of Pitting Potential)

[0089] A tube and a fin were cut out from the test sample for evaluation, and portions other than the measurement surface were masked with epoxy resin. These were used as test materials, and as a pretreatment, the surfaces of the test materials were cleaned by immersing in a 5% NaOH aqueous solution at 60 C. for 30 seconds and in a 30% HNO.sub.3 aqueous solution for 60 seconds. Subsequently, acetic acid was added to a 5% NaCl aqueous solution to adjust to pH 3, which was subjected to deaeration with nitrogen for 30 minutes to prepare a measurement solution. The tube or the fin was immersed in the measurement solution at 25 C., and an anodic polarization curve was measured using a potentiostat. In the polarization curve, the potential at which the current suddenly increased was defined as the pitting potential. The results are shown in Table 5.

(Corrosion Resistance)

[0090] A test sample for evaluation was subjected to a cycle corrosion test including spraying for 2 hours (spray amount: 1 to 2 ml/80 cm.sup.2/h) using, as a spray liquid, an aqueous solution at pH 2.3 containing 6 ppm of hydrochloric acid, 10 ppm of sulfuric acid, 10 ppm of nitric acid, 5000 ppm of acetic acid and 5000 ppm of formic acid, drying (relative humidity: 20 to 30%) for 2 hours, and humidifying (relative humidity: 95% or more) for 2 hours. The temperature in the test chamber was set at 50 C., and the test time was set to 3000 hours. After completion of the test, the corrosion products were removed with concentrated nitric acid. The depth of the corroded pores generated on the surface of the sacrificial anticorrosion material was then measured by the focal depth method to determine a maximum one as the corrosion depth. A sample having a maximum corrosion depth of 100 m or less was considered to be good, and a sample having a maximum corrosion depth of 100 m or more was considered to be poor. The results are shown in Table 5 to Table 7.

TABLE-US-00001 TABLE 1 Si Cu Mn Fe Mg Ni Ti V Cr Zr Al A1 0.50 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A2 0.05 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A3 1.50 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A4 0.50 0.05 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A5 0.50 3.00 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A6 0.50 0.50 0.40 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A7 0.50 0.50 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A8 0.50 0.50 1.00 0.10 0.05 0.00 0.00 0.00 0.00 0.00 bal. A9 0.50 0.50 1.00 0.10 0.50 0.00 0.00 0.00 0.00 0.00 bal. A10 0.50 0.50 1.00 0.20 0.00 0.00 0.00 0.00 0.00 0.00 bal. A11 0.50 0.50 1.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. A12 0.50 0.50 1.00 0.10 0.00 0.05 0.00 0.00 0.00 0.00 bal. A13 0.50 0.50 1.00 0.10 0.00 1.00 0.00 0.00 0.00 0.00 bal. A14 0.50 0.50 1.00 0.10 0.00 0.00 0.05 0.00 0.00 0.00 bal. A15 0.50 0.50 1.00 0.10 0.00 0.00 0.30 0.00 0.00 0.00 bal. A16 0.50 0.50 1.00 0.10 0.00 0.00 0.00 0.05 0.00 0.00 bal. A17 0.50 0.50 1.00 0.10 0.00 0.00 0.00 0.30 0.00 0.00 bal. A18 0.50 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.05 0.00 bal. A19 0.50 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.30 0.00 bal. A20 0.50 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.05 bal. A21 0.50 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.30 bal. A22 0.01 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A23 2.00 0.50 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A24 0.50 0.01 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A25 0.50 5.00 1.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A26 0.50 0.50 0.30 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal. A27 0.50 0.50 2.50 0.10 0.00 0.00 0.00 0.00 0.00 0.00 bal.

TABLE-US-00002 TABLE 2 Si Zn Fe Mn Mg Ni In Sn Ti V Cr Zr Al B1 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B2 3.00 2.00 0.10 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B3 13.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B4 7.00 0.50 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B5 7.00 6.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B6 7.00 2.00 0.10 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B7 7.00 2.00 0.10 2.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B8 7.00 2.00 0.10 0.00 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B9 7.00 2.00 0.10 0.00 0.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B10 7.00 2.00 0.20 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B11 7.00 2.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B12 7.00 2.00 0.10 0.00 0.00 0.05 0.00 0.00 0.00 0.00 0.00 0.00 bal. B13 7.00 2.00 0.10 0.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B14 7.00 2.00 0.10 0.00 0.00 0.00 0.05 0.00 0.00 0.00 0.00 0.00 bal. B15 7.00 2.00 0.10 0.00 0.00 0.00 0.30 0.00 0.00 0.00 0.00 0.00 bal. B16 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.05 0.00 0.00 0.00 0.00 bal. B17 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.30 0.00 0.00 0.00 0.00 bal. B18 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.05 0.00 0.00 0.00 bal. B19 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.30 0.00 0.00 0.00 bal. B20 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.05 0.00 0.00 bal. B21 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.30 0.00 0.00 bal. B22 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.05 0.00 bal. B23 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 0.00 bal. B24 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.05 bal. B25 7.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 bal. B26 2.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B27 15.00 2.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B28 7.00 0.10 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal. B29 7.00 8.00 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 bal.

TABLE-US-00003 TABLE 3 Si Zn Al D1 7.00 0.00 bal. D2 3.00 0.00 bal. D3 13.00 0.00 bal. D4 7.00 0.05 bal. D5 7.00 2.00 bal.

TABLE-US-00004 TABLE 4 Si Mn Zn Fe Mg Al C1 0.50 1.00 0.00 0.10 0.00 bal. C2 0.05 1.00 0.00 0.10 0.00 bal. C3 1.50 1.00 0,00 0.10 0.00 bal. C4 0.50 0.40 0.00 0.10 0.00 bal. C5 0.50 2.00 0.00 0.10 0.00 bal. C6 0.50 1.00 0.05 0.10 0.00 bal. C7 0.50 1.00 0.00 0.10 0.05 bal. C8 0.50 1.00 0.00 0.10 0.50 bal. C9 0.50 1.00 0.00 0.20 0.00 bal. C10 0.50 1.00 0.00 1.00 0.00 bal. C11 0.01 1.00 0.00 0.10 0.00 bal. C12 2.00 1.00 0.00 0.10 0.00 bal. C13 0.50 0.20 0.00 0.10 0.00 bal. C14 0.50 2.50 0.00 0.10 0.00 bal. C15 0.50 1.00 0.20 0.10 0.00 bal. C16 0.50 1.00 2.00 0.10 0.00 bal

TABLE-US-00005 TABLE 5 (Potential of fin)- (Pitting potential Corrosion Tube/ Tube/ Fin/ Fin/ of tube test Core Sacrificial Tube/ Core Brazing surface)/ result/ material material Brazing material material mV m Example 1 A1 B1 C1 82 64 Example 2 A2 B1 C1 84 52 Example 3 A3 B1 C1 90 64 Example 4 A4 B1 C1 86 54 Example 5 A5 B1 C1 86 64 Example 6 A6 B1 C1 76 54 Example 7 A7 B1 C1 84 64 Example 8 A8 B1 C1 84 42 Example 9 A9 B1 C1 90 36 Example 10 A10 B1 C1 86 40 Example 11 A11 B1 C1 90 30 Example 12 A12 B1 C1 92 48 Example 13 A13 B1 C1 76 40 Example 14 A14 B1 C1 78 40 Example 15 A15 B1 C1 78 48 Example 16 A16 B1 C1 76 48 Example 17 A17 B1 C1 84 48 Example 18 A18 B1 C1 78 40 Example 19 A19 B1 C1 88 30 Example 20 A20 B1 C1 84 38 Example 21 A21 B1 C1 92 32 Example 22 A1 B1 C1 D1 81 58 Example 23 A1 B1 C1 D2 78 61 Example 24 A1 B1 C1 D3 80 52 Example 25 A1 B1 C1 D4 80 59 Example 26 A18 B1 D1 C1 78 40 Example 27 A19 B1 D2 C1 88 30 Example 28 A20 B1 D3 C1 84 38 Example 29 A21 B1 D4 C1 92 32

TABLE-US-00006 TABLE 6 (Potential of fin)- (Pitting potential Corrosion Tube/ Tube/ Fin/ Fin/ of tube test Core Sacrificial Tube/ Core Brazing surface)/ result/ material material Brazing material material mV m Example 30 A1 B2 C1 73 68 Example 31 A1 B3 C1 89 64 Example 32 A1 B4 C1 46 86 Example 33 A1 B5 C1 185 68 Example 34 A1 B6 C1 73 30 Example 35 A1 B7 C1 73 48 Example 36 A1 B8 C1 92 40 Example 37 A1 B9 C1 86 32 Example 38 A1 B10 C1 92 34 Example 39 A1 B11 C1 76 48 Example 40 A1 B12 C1 80 50 Example 41 A1 B13 C1 86 48 Example 42 A1 B14 C1 109 40 Example 43 A1 B15 C1 163 44 Example 44 A1 B16 C1 101 36 Example 45 A1 B17 C1 165 36 Example 46 A1 B18 C1 84 46 Example 47 A1 B19 C1 76 38 Example 48 A1 B20 C1 76 48 Example 49 A1 B21 C1 86 30 Example 50 A1 B22 C1 80 34 Example 51 A1 B23 C1 90 44 Example 52 A1 B24 C1 78 34 Example 53 A1 B25 C1 92 38 Example 54 A1 B1 D1 C1 82 64 Example 55 A1 B1 D2 C1 82 64 Example 56 A1 B1 D3 C1 82 64 Example 57 A1 B1 D4 C1 82 64 Example 58 A1 B1 C2 99 68 Example 59 A1 B1 C3 71 52 Example 60 A1 B1 C4 77 52 Exampe 61 A1 B1 C5 96 64 Example 62 A1 B1 C6 76 70 Example 63 A1 B1 C7 77 44 Example 64 A1 B1 C8 88 42 Example 65 A1 B1 C11 80 42 Example 66 A1 B1 C12 92 34

TABLE-US-00007 TABLE 7 (Potential of fin)- (Pitting potential Corrosion Tube/ Tube/ Fin/ Fin/ of tube test Core Sacrificial Tube/ Core Brazing surface)/ result/ material material Brazing material material mV m Comparative A22 B1 C1 86 86 Example 1 Comparative A24 B1 C1 90 124 Example 2 Comparative A26 B1 C1 88 88 Example 3 Comparative A1 B26 C1 55 55 Example 4 Comparative A1 B28 C1 5 150 Example 5 Comparative A1 B1 C11 89 78 Example 6 Comparative A1 B1 C13 62 90 Example 7 Comparative A1 B1 C15 7 201 Example 8 Comparative A23 B1 C1 Example 9 Comparative A25 B1 C1 Example 10 Comparative A27 B1 C1 Example 11 Comparative A1 B27 C1 Example 12 Comparative A1 B29 C1 Example 13 Comparative A1 B1 C12 Example 14 Comparative A1 B1 C14 Example 15 Comparative A1 B1 C16 54 251 Example 16 Comparative A1 B1 C1 D5 50 271 Example 17

[0091] In all Examples, there existed no problem with manufacturability of the tube material or the fin material, the brazing property was good with a tube strength after brazing of 140 MPa or more and a fin strength after brazing of 120 MPa or more, and the corrosion resistance after the cycle corrosion test was excellent.

[0092] In Comparative Example 1, the tube core material had a low Si content, so that the tube after brazing had a low strength of 136 MPa.

[0093] In Comparative Example 2, the tube core material had a low Cu content, so that the tube after brazing had a low strength of 129 MPa.

[0094] In Comparative Example 3, the tube core material had a low Mn content, so that the tube after brazing had a low strength of 134 MPa.

[0095] In Comparative Example 4, the sacrificial anode material had a low Si content, so that defective brazing of the fin occurred.

[0096] In Comparative Example 5, the sacrificial anode material had a low Zn content, so that the corrosion resistance of the tube was poor.

[0097] In Comparative Example 6, the fin material had a low Si content, so that the fin after brazing had a low strength of 102 MPa.

[0098] In Comparative Example 7, the fin material had a low Mn content, so that the fin after brazing had a low strength of 74 MPa. In Comparative Example 8, the fin material had a low Zn content, so that the corrosion resistance was poor.

[0099] In Comparative Examples 9 to 15, melting or cracking occurred during manufacturing of the tube material or the fin material, so that the subsequent evaluations were unable to be performed.

[0100] In Comparative Example 16, the core material of the fin had a high Zn content, so that the fin was corroded in an early stage, so that the corrosion resistance of the tube was poor.

[0101] In Comparative Example 17, the brazing material of the fin had a high Zn content, so that the fin was corroded in an early stage and the corrosion resistance of the tube was poor.