Abstract: An aluminum alloy brazing sheet including a core material, a sacrificial material provided on one surface of the core material, a brazing filler material provided on the other surface side of the core material, and an intermediate layer provided between the core material and the brazing filler material. The core material contains Si: 0.30 to 1.00 mass %, Mn: 0.50 to 2.00 mass %, Cu: 0.60 to 1.20 mass %, Mg: 0.05 to 0.80 mass %, and Al. The sacrificial material contains Si: 0.10 to 1.20 mass %, Zn: 2.00 to 7.00 mass %, Mn: 0.40 mass % or less, and Al. The intermediate layer contains Si: 0.05 to 1.20 mass %, Mn: 0.50 to 2.00 mass %, Cu: 0.10 to 1.20 mass %, and Al.

Abstract: An aluminum alloy brazing sheet including a core material, a sacrificial material provided on one surface of the core material, a brazing filler material provided on the other surface side of the core material, and an intermediate layer provided between the core material and the brazing filler material. The core material contains Si: 0.30 to 1.00 mass %, Mn: 0.50 to 2.00 mass %, Cu: 0.60 to 1.20 mass %, Mg: 0.05 to 0.80 mass %, and Al. The sacrificial material contains Si: 0.10 to 1.20 mass %, Zn: 2.00 to 7.00 mass %, Mn: 0.40 mass % or less, and Al. The intermediate layer contains Si: 0.05 to 1.20 mass %, Mn: 0.50 to 2.00 mass %, Cu: 0.10 to 1.20 mass %, and Al.

Abstract: An aluminum alloy brazing sheet used for brazing in an inert gas atmosphere without using flux is provided. In the aluminum alloy brazing sheet, a brazing material formed of aluminum alloy including Si of 6 mass % to 13 mass % with the balance being Al and inevitable impurities clads one side surface or both side surfaces of a core material formed of aluminum alloy including Mn of 0.8 mass % to 1.8 mass %, and Mg of 0.05 mass % to 0.20 mass % with the balance being Al and inevitable impurities, the brazing sheet has a thickness of 0.12 mm or smaller, and the brazing material has a thickness of 0.012 mm or smaller. This structure provides an aluminum alloy brazing sheet for fluxless brazing causing no defectiveness of buckling of distal end portions of fins or unsound formation of a fillet in brazing heating.

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: 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: A tube for a heat exchanger is formed by bending a three-layer clad material of an aluminum alloy to have an overlapped portion. The three-layer clad material is formed by a core material layer containing Mg not smaller than 0.2 wt % after brazing, a brazing material layer on one surface of the core material layer, and a high melting-point material layer on the other surface of the core material layer. The brazing material layer has a thickness not smaller than 25 ?m before the brazing, and has a melting point lower than 600° C. The high melting-point material layer has a melting point equal to or higher than 600° C. In addition, the brazing material layer and the high melting-point material layer opposite to each other in the overlapped portion are bonded by the brazing at a temperature not lower than 450° C. for a time within 12 minutes.

Abstract: A tube for a heat exchanger is formed by bending a three-layer clad material of an aluminum alloy to have an overlapped portion. The three-layer clad material is formed by a core material layer containing Mg not smaller than 0.2 wt % after brazing, a brazing material layer on one surface of the core material layer, and a high melting-point material layer on the other surface of the core material layer. The brazing material layer has a thickness not smaller than 25 ?m before the brazing, and has a melting point lower than 600° C. The high melting-point material layer has a melting point equal to or higher than 600° C. In addition, the brazing material layer and the high melting-point material layer opposite to each other in the overlapped portion are bonded by the brazing at a temperature not lower than 450° C. for a time within 12 minutes.

Abstract: A brazing filler metal includes quaternary alloy powder and copper powder. The quaternary allow powder consists of from 0.1 to 27.4 mass percent tin, from 0.8 to 5.1 mass percent nickel, from 2.2 to 10.9 mass percent phosphorous and a balance including copper and any unavoidable impurity. The brazing filler metal can be used in a form of paste by being mixed with an organic binder and an organic solvent. The brazing filler metal and the brazing filler metal can be used for joining members made of copper or copper alloy, such as members of a heat exchanger.

Abstract: A brazing method is provided for brazing a metallic material for brazing to another metallic material. The metallic material for brazing includes a base material portion made of copper or a copper alloy containing chrome by a predetermined amount, and a metallic film portion made of a material having a melting point lower than a heating temperature in brazing, and provided on the surface of the base material portion. The brazing method includes a step of assembling the metallic material for brazing and the another metallic material to form an assembly, a step of heating and brazing the assembly, in which the metallic film portion is melted to diffuse chrome into a surface of the metallic material for brazing, and a step of forming a chrome oxide film by using the chrome diffused into the surface of the metallic material for brazing in atmosphere after the brazing step.