Abstract: An aqueous aluminum brazing composition containing an organic binder and zinc-based flux which prevents precipitation of the zinc-based flux having a large specific gravity while securing excellent brazeability. The thixotropic index of the brazing composition is adjusted to 1.01-1.20 by adding (meth)acrylic acid/(meth)acrylate copolymer emulsion to the brazing composition as a precipitation inhibitor in an amount of 0.03-1.50 wt % of 100 wt % of the brazing composition. Since the (meth)acrylic acid/(meth)acrylate copolymer emulsion is used as the precipitation inhibitor in a specific amount instead of other types of compounds used for powder-containing paint such as ultrafine particle silica, poly(meth)acrylate, or polyvinyl alcohol, precipitation of the zinc-based flux can be prevented without impairing brazeability.

Abstract: The present invention provides an aluminum alloy fin material for heat exchangers which has a thickness of 80 ?m (0.08 mm) or less and excels in joinability to a tube material and in intergranular corrosion resistance. The aluminum alloy fin material is an aluminum alloy bare fin material or a brazing fin material which has a thickness of 80 ?m or less and is incorporated into a heat exchanger made of an aluminum alloy manufactured by brazing through an Al—Si alloy filler metal. The structure of the core material before brazing is a fiber structure, and the crystal grain diameter of the structure after brazing is 50–250 ?m. The Si concentration in the Si dissolution area on the surface of the fin material and at the center of the thickness of the fin material after brazing is preferably 0.8% or more and 0.7% or less, respectively.

Abstract: The present invention provides an aluminum alloy fin material for heat exchangers which has a thickness of 80 &mgr;m (0.08 mm) or less and excels in joinability to a tube material and in intergranular corrosion resistance. The aluminum alloy fin material is an aluminum alloy bare fin material or a brazing fin material which has a thickness of 80 &mgr;m or less and is incorporated into a heat exchanger made of an aluminum alloy manufactured by brazing through an Al—Si alloy filler metal. The structure of the core material before brazing is a fiber structure, and the crystal grain diameter of the structure after brazing is 50-250 &mgr;m. The Si concentration in the Si dissolution area on the surface of the fin material and at the center of the thickness of the fin material after brazing is preferably 0.8% or more and 0.7% or less, respectively.

Abstract: There is disclosed a heat exchanger made of an aluminum alloy having a radiator part (10) and an oil cooler part (11) in combination and manufactured integrally by the brazing method, wherein a refrigerant tank (13) for covering and sealing the oil cooler part is made of an aluminum alloy, an aluminum alloy containing Si in an amount from more than 7.0 wt % to 12.0 wt %, Fe in an amount from more than 0.05 wt % to 0.5 wt %, Cu in an amount from more than 0.4 wt % to 8.0 wt %, Zn in an amount from more than 0.5 wt % to 10.0 wt %, and the balance of aluminum and inevitable impurities is used as a filler material of brazing sheets that are used for the oil cooler part and are brazed in the tank, and the refrigerant tank is assembled integrally with the radiator part and the oil cooler part by brazing with the brazing material.

Abstract: A core material of an aluminum brazing sheet restricts Mg to less than 0.3 wt % and Fe to not more than 0.2 wt %, and contains more than 0.2 wt % and not more than 1.0 wt % of Cu, 0.3 to 1.3 wt % of Si, 0.3 to 1.5 wt % of Mn and the balance of Al and inevitable impurities. A brazing filler material is formed on one surface of the core material by Al—Si based aluminum alloy. Also, a cladding material is formed on the other surface of the core material, and contains less than 0.2 wt % of Si, 2.0 to 3.5 wt % of Mg, not less than 0.5 wt % and less than 2.0 wt % of Zn and the balance of Al and inevitable impurities. Further, the value (cladding material hardness)/(the core material hardness) that is a ratio of the hardness of the cladding material to the hardness of the core material is not more than 1.5.

Abstract: A core material of an aluminum brazing sheet restricts Mg to less than 0.3 wt. % and Fe to not more than 0.2 wt. %, and contains more than 0.2 wt. % and not more than 1.0 wt. % of Cu, 0.3 to 1.3 wt. % of Si, 0.3 to 1.5 wt. % of Mn and the balance of Al and inevitable impurities. A brazing filler material is formed on one surface of the core material by Al-Si based aluminum alloy. Also, a cladding material is formed on the other surface of the core material, and contains less than 0.2 wt. % of Si, 2.0 to 3.5 wt. % of Mg, not less than 0.5 wt. % and less than 2.0 wt. % of Zn and the balance of Al and inevitable impurities. Further, the value (cladding material hardness)/(the core material hardness) that is a ratio of the hardness of the cladding material to the hardness of the core material is not more than 1.5.

Abstract: There is disclosed a heat exchanger made of an aluminum alloy having a radiator part (10) and an oil cooler part (11) in combination and manufactured integrally by the brazing method, wherein a refrigerant tank (13) for covering and sealing the oil cooler part is made of an aluminum alloy, an aluminum alloy containing Si in an amount from more than 7.0 wt % to 12.0 wt %, Fe in an amount from more than 0.05 wt % to 0.5 wt %, Cu in an amount from more than 0.4 wt % to 8.0 wt %, Zn in an amount from more than 0.5 wt % to 10.0 wt %, and the balance of aluminum and inevitable impurities is used as a filler material of brazing sheets that are used for the oil cooler part and are brazed in the tank, and the refrigerant tank is assembled integrally with the radiator part and the oil cooler part by brazing with the brazing material.

Abstract: An aluminum alloy clad material for heat exchangers exhibiting superior strength after brazing and excellent corrosion resistance is provided. The aluminum alloy clad material comprises a sacrificial anode material which is clad on one side of a core material, wherein the core material comprises an aluminum alloy comprising 0.3-2.0% of Mn, 0.25-1.0% of Cu, 0.3-1.1% of Si, and 0.05-0.35% of Ti with the remaining portion consisting of aluminum and impurities, the sacrificial anode material comprises an aluminum alloy comprising 1.5-8% of Zn, 0.01-0.8% of Si, and 0.01-0.3% of Fe with the remaining portion consisting of aluminum and impurities, and the total number of particles of Si compounds and Fe compounds with a particle diameter (circle equivalent diameter) of 1 &mgr;m or more present in the sacrificial anode material matrix is 2×104 or less per 1 mm2. The clad material is suitably used as a tube material or header plate material for automotive heat exchangers such as a radiator or heater core.

Abstract: There is disclosed an aluminum alloy tube whose outer surface is covered with a filler alloy by metal-spraying, wherein the base material of the tube has an uneven rough surface with the depth of 10 &mgr;m or more, and the difference between the highest projection of the base material surface and the highest projection of the filler alloy layer covering it is 3 to 25 &mgr;m; a heat exchanger, which is assembled by using the tubes; and a method of metal-spraying, which comprises metal-spraying an aluminum alloy filler powder in a melted state, by the high-velocity flame metal-spraying process, in which the filler contains 15 to 50% Si by weight, and the powder is mainly made up of particles whose diameter is 10 &mgr;m to 70 &mgr;m. The aluminum alloy tube is excellent in brazability and corrosion resistance, and by using the tube, it is possible to assemble a heat exchanger without allowing locally filler-unbonded parts to be formed.