Abstract: A method for brazing aluminum alloy-assembled articles with a filler alloy having a liquidus temperature of 540° C. or lower and a difference of temperature between the liquidus temperature and the solidus temperature being 100° C. or lower, wherein the highest temperature reached in the assembled article at the time of heating for brazing being set 40° C. or more higher than the liquidus temperature but 585° C. or lower. An aluminum alloy-filler alloy usable at low temperature for brazing, which comprises Si in an amount of 4.0 wt % to 8.0 wt %, Zn in an amount of 7.0 wt % to 20.0 wt % and Cu in an amount of 10.0 wt % to 35.0 wt %, with the balance being made of aluminum.

Abstract: In a manufacturing method of a heat exchanger including a core portion having a plurality of tubes and a plurality of radiation fins connected to surfaces of the tubes, and a tank portion communicating with the tubes, a preheating step, a brazing step, a gradual cooling step and a cooling step are performed in this order. In the preheating step, temperature of the tank portion having a large heat capacity is increased earlier than that of the core portion having a small heat capacity. Therefore, the temperature of the tank portion is rapidly increased, and the temperature of the core portion is obediently increased in accordance with the temperature increase of the tank portion.

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: In a manufacturing method of a heat exchanger including a core portion having a plurality of tubes and a plurality of radiation fins connected to surfaces of the tubes, and a tank portion communicating with the tubes, a preheating step, a brazing step, a gradual cooling step and a cooling step are performed in this order. In the preheating step, temperature of the tank portion having a large heat capacity is increased earlier than that of the core portion having a small heat capacity. Therefore, the temperature of the tank portion is rapidly increased, and the temperature of the core portion is obediently increased in accordance with the temperature increase of the tank portion.

Abstract: A method for brazing aluminum alloy-assembled articles with a filler alloy having a liquidus temperature of 540° C. or lower and a difference of temperature between the liquidus temperature and the solidus temperature being 100° C. or lower, wherein the highest temperature reached in the assembled article at the time of heating for brazing being set 40° C. or more higher than the liquidus temperature but 585° C. or lower. An aluminum alloy-filler alloy usable at low temperature for brazing, which comprises Si in an amount of 4.0 wt % to 8.0 wt %, Zn in an amount of 7.0 wt % to 20.0 wt % and Cu in an amount of 10.0 wt % to 35.0 wt %, with the balance being made of aluminum.

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: Work W to which oil has adhered is heated in the heating furnace 28 and adhering oil is evaporated. Gas containing the evaporated oil component is burned in the combustor 35. A portion of the generated combustion gas is circulated into the heating furnace 28 through the circulating duct 38, and an amount of the circulating combustion gas is controlled in accordance with a temperature in the heating furnace 28. Processing of aluminum materials is carried out using a base oil of hydrocarbon, the maximum molecular weight M of which is not less than 282 and not more than 378, and an additive of not less than 3% by weight of alcohol or carboxylic acid, the maximum molecular weight M of which is not more than 378.