Abstract: An aluminum alloy brazing sheet makes it possible to implement a stable brazability equal to that achieved by brazing using flux even if an etching treatment is not performed on the brazing site. The aluminum alloy brazing sheet is used to braze aluminum in an inert gas atmosphere without using flux, the brazing sheet including a core material and a filler metal, one side or each side of the core material being clad with the filler metal, the core material being formed of an aluminum alloy that includes 0.2 to 1.3 mass % of Mg, the filler metal including 6 to 13 mass % of Si and 0.004 to 0.1 mass % of Li, with the balance being aluminum and unavoidable impurities, a surface oxide film having been removed from the brazing sheet, and an oil solution that decomposes when heated at 380° C. or less in an inert gas having been applied to the brazing sheet.

Abstract: In a method for brazing a sheet material without use of flux, an inert gas is firstly introduced into an oxygen pump to reduce an oxygen partial pressure in the inert gas to 1×10?10 Pa or less, and the sheet material is heated in a brazing furnace in an atmosphere of the inert gas discharged from the oxygen pump. A core alloy of the sheet material or a brazing filler alloy cladded to a surface of the core alloy contains Mg. Both the core alloy and the brazing filler alloy may contain Mg. Accordingly, brazability of the sheet material is sufficiently improved.

Abstract: An aluminum alloy heat exchanger is produced by applying a coating material that is prepared by adding a binder to a mixture of an Si powder and a Zn-containing compound flux powder to a surface of an aluminum alloy refrigerant tube, assembling a bare fin that is formed of an Al—Mn—Zn alloy with the refrigerant tube, and brazing the refrigerant tube and the bare fin by heating in an atmosphere-controlled furnace, the refrigerant tube being an extruded product of an aluminum alloy that comprises 0.5 to 1.7% (mass %, hereinafter the same) of Mn, less than 0.10% of Cu, and less than 0.

Abstract: An aluminum alloy clad sheet for heat exchangers includes a core material, a cladding material 1, and a cladding material 2, one side and the other side of the core material being respectively clad with the cladding material 1 and the cladding material 2, the core material containing 0.5 to 1.2% of Si, 0.2 to 1.0% of Cu, and 1.0 to 1.8% of Mn, with the balance being Al and unavoidable impurities, the cladding material 1 containing 3 to 6% of Si, 2 to 8% of Zn, and at least one of 0.3 to 1.8% of Mn and 0.05 to 0.3% of Ti, with the balance being Al and unavoidable impurities, and the cladding material 2 containing 6 to 13% of Si, with the balance being Al and unavoidable impurities, the cladding material 1 being positioned on the outer side of the aluminum alloy clad sheet during use.

Abstract: An aluminum alloy clad sheet for heat exchangers includes a core material, a cladding material 1, and a cladding material 2, one side and the other side of the core material being respectively clad with the cladding material 1 and the cladding material 2, the core material containing 0.5 to 1.2% of Si, 0.2 to 1.0% of Cu, 1.0 to 1.8% of Mn, and 0.05 to 0.3% of Ti, with the balance being Al and unavoidable impurities, the cladding material 1 containing 3 to 6% of Si, 2 to 8% of Zn, and at least one of 0.3 to 1.8% of Mn and 0.05 to 0.3% of Ti, with the balance being Al and unavoidable impurities, and the cladding material 2 containing 6 to 13% of Si, with the balance being Al and unavoidable impurities, the cladding material 1 serving as the outer side of the aluminum alloy clad sheet during use.

Abstract: The present invention provides a method of manufacturing a heat exchanger tube in which a tube for a heat exchanger formed by brazing is manufactured using a sheet material, wherein a filler metal melted during brazing can be prevented from entering an opening formed in an opposing portion or a parallel portion formed when bending a sheet material into a tube shape or an opening facing toward the outside of the tube. The opposing portion, the parallel portion, or the opening facing toward the outside of the tube is sealed. As the sealing means, friction welding is preferable.

Abstract: The present invention provides a heat exchanger which is assembled by brazing an aluminum fin material to the outer surface of an aluminum tube material formed by bending a sheet material, in particular, an aluminum heat exchanger which can be suitably used as an automotive heat exchanger such as a condenser or evaporator. The tube material is formed of a two-layer clad sheet which includes a core material and an Al—Zn alloy layer clad on the core material. The Al—Zn alloy layer is clad on the outer surface of the tube material and brazed to the aluminum fin material. The potential of the Al—Zn alloy layer in a normal corrosive solution is at least 100 mV lower than the potential of the core material in the normal corrosive solution. The potential of the Al—Zn alloy layer in the normal corrosive solution is lower than the potential of the core material in high-concentration corrosive water. The normal corrosive solution refers to an aqueous solution containing 10 g/l of NaCl and 0.

Abstract: The present invention provides a method of manufacturing a heat exchanger tube in which a tube for a heat exchanger formed by brazing is manufactured using a sheet material, wherein a filler metal melted during brazing can be prevented from entering an opening formed in an opposing portion or a parallel portion formed when bending a sheet material into a tube shape or an opening facing toward the outside of the tube. The opposing portion, the parallel portion, or the opening facing toward the outside of the tube is sealed. As the sealing means, friction welding is preferable.

Abstract: A sheet material for the tube 10 includes: a core material 10b; and a sacrifical corrosion material 10c clad on one face of the core material 10b which becomes an outside of the tube 10. A sheet material for the fin is a bare aluminum material on which a brazing filler metal is not clad. A mixture composition 10e, in which powder of a brazing filler metal and flux are mixed with each other, is coated on the outside of the tube 10. The tube 10 and the fin are brazed to each other with this mixture composition 10e. Even after the completion of brazing, the sacrifical corrosion material 10c remains on the outside of the tube 10.

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: A high-strength aluminum alloy extruded product for heat exchangers which excels in extrudability, allows a thin flat multi-cavity tube to be extruded at a high critical extrusion rate, and excel in intergranular corrosion resistance at a high temperature, and a method of manufacturing the same. The aluminum alloy extruded product includes an aluminum alloy including 0.2 to 1.8% of Mn and 0.1 to 1.2% of Si, having a ratio of Mn content to Si content (Mn %/Si %) of 0.7 to 2.5, and having a content of Cu as an impurity of 0.05% or less, with the balance being Al and impurities, the aluminum alloy extruded product having an electric conductivity of 50% IACS or more and an average particle size of intermetallic compounds precipitating in a matrix of 1 ?m or less.

Abstract: An object of the present invention is to provide a filler metal for an aluminum brazing sheet for heat exchangers capable of preventing or controlling occurrence of a melting hole during heating for brazing, and a method of manufacturing the same. In an Al—Si alloy filler metal which is clad on the aluminum brazing sheet and melted during heating for brazing, the maximum particle diameter of a coarse Si particle crystallized in the eutectic structure of the filler metal is 20 ?m or less. Provided that an average value and a standard deviation in a normal distribution of the particle diameter of the coarse Si particle in the filler metal are respectively ? and ?, (?+3?) is preferably 10 ?m or less. This brazing sheet is obtained by a method of adding a specific amount of Na, Sr, or Sb to the filler metal, a method of limiting the amount of impurities in the filler metal within a specific range, a method of specifying a cooling rate during the casting of the filler metal, or the like.

Abstract: The present invention provides a heat exchanger which is assembled by brazing an aluminum fin material to the outer surface of an aluminum tube material formed by bending a sheet material, in particular, an aluminum heat exchanger which can be suitably used as an automotive heat exchanger such as a condenser or evaporator. The tube material is formed of a two-layer clad sheet which includes a core material and an Al—Zn alloy layer clad on the core material. The Al—Zn alloy layer is clad on the outer surface of the tube material and brazed to the aluminum fin material. The potential of the Al—Zn alloy layer in normal corrosive solution is 100 mV or more lower than the potential of the core material in the normal corrosive solution. The potential of the Al—Zn alloy layer in the normal corrosive solution is lower than the potential of the core material in high-concentration corrosive water. The normal corrosive solution refers to an aqueous solution containing 10 g/l of NaCl and 0.

Abstract: A method for brazing a magnesium-containing aluminum alloy material exhibiting excellent brazing performance when applied to brazing an aluminum alloy material containing 0.2-1.0% of magnesium used in cladding parts of vehicle heat exchanger tubes and the like using potassium fluorozincate and an Al—Si-alloy brazing material in an inert gas atmosphere can be provided. The method is characterized by brazing the magnesium-containing aluminum alloy by applying potassium fluorozincate having a composition of KxZnyFz (wherein x, y, and z are positive integers) to the brazing part at a concentration of (1.65×Mg %/T) g/m2 or more (wherein T is an average temperature rising rate (° C./second) of the aluminum alloy from 550° C. to the brazing temperature), and heating at an average temperature rising rate (T) of 0.1° C./second or more.

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: An object of the present invention is to provide a filler metal for an aluminum brazing sheet for heat exchangers capable of preventing or controlling occurrence of a melting hole during heating for brazing, and a method of manufacturing the same. In an Al—Si alloy filler metal which is clad on the aluminum brazing sheet and melted during heating for brazing, the maximum particle diameter of a coarse Si particle crystallized in the eutectic structure of the filler metal is 20 &mgr;m or less. Provided that an average value and a standard deviation in a normal distribution of the particle diameter of the coarse Si particle in the filler metal are respectively &mgr; and &sgr;, (&mgr;+3&sgr;) is preferably 10 &mgr;m or less.

Abstract: A vacuum-brazing aluminum cladding material consisting of a core member and a first and a second clad which cover at least one surface of the core member. The first clad consists of 6-14% by weight of Si, 0-0.6% by weight of Mg and the balance being at least Al, and the second clad formed on the first clad consists of 0-14% by weight of Si, 0.8-2.5% by weight of Mg and the balancing being at least Al. The second clad has a thickness of at least 5"m, and this thickness and a content of Si determined so as to satisfy a formula t.ltoreq..vertline.100/(10-c).vertline., wherein, "t" is the thickness (.mu.m) of said second alloy clad, and "c" is the content (% by weight) os Si of the second clad.