METHOD FOR BRAZING SHEET MATERIAL AND HEAT EXCHANGER

摘要

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.

主权项

1. A method for brazing a sheet material without use of flux, the sheet material including (i) a core alloy containing Al as a major component, more than 0 mass % and less than or equal to 1.8 mass % of Mn, and unavoidable impurities, and (ii) a brazing filler alloy cladded to a surface of the core alloy, the brazing filler alloy containing Al as a major component, 0.1 to 1.2 mass % of Mg, 4 to 13 mass % of Si, and unavoidable impurities, the method comprising:
reducing a partial pressure of oxygen contained in an inert gas; and joining the sheet material in an atmosphere of the inert gas, wherein the reducing of the partial pressure of oxygen includes:
introducing the inert gas into an oxygen pump provided with a solid electrolyte having an oxygen ion conductivity; andapplying a voltage to the solid electrolyte to reduce the partial pressure of oxygen to 1×10−10 Pa or less, and the joining of the sheet material includes:
introducing the inert gas from the oxygen pump into a brazing furnace; andheating the sheet material in the atmosphere of the inert gas in the brazing furnace.