Method for manufacturing cooling unit

Abstract

Provided is a manufacturing method for a cooler, including brazing: a cooling plate () made of an aluminum alloy containing 0.35 mass % to 0.9 mass % of Mg and 0.2 mass % to 0.9 mass % of Si and having a substantially flat rectangular cross section; first and second refrigerant introduction members () each made of an aluminum alloy, which are connected to end portions of the cooling plate (); and a refrigerant supply pipe () and a refrigerant discharge pipe () each made of an aluminum alloy, which are connected to a refrigerant supply port () and a refrigerant discharge port (), respectively, the refrigerant supply port () and the refrigerant discharge port () being arranged in one of the first and second refrigerant introduction members (), to each other, wherein the brazing includes subjecting a connecting portion of the cooling plate (), the first and second refrigerant introduction members (), the refrigerant supply pipe (), and the refrigerant discharge pipe () to high-frequency brazing with an aluminum alloy brazing filler metal containing 27 mass % to 37 mass % of Cu and 5 mass % to 10 mass % of Si, with the balance being Al and inevitable impurities, and a fluoride-based flux containing 11 mass % or more of CsF as a solid content through heating with a high-frequency heating coil.