Method for brazing sheet material and heat exchanger

• Main Authors: OZAWA SHUMPEI, NAGASAWA TOHRU, TAKEWAKA SHIN, MATSUSHITA HARUHIKO, YAMAYOSHI TOMOKI, ITOH YASUNAGA, YAMADA SHOGO
• Format: Patent
• Language: English
• Published: 14.06.2016
• Subjects: ALLOYS; BLASTING; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OFGENERAL APPLICATION; FERROUS OR NON-FERROUS ALLOYS; HEAT EXCHANGE IN GENERAL; HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS,IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT; HEATING; LIGHTING; MACHINE TOOLS; MECHANICAL ENGINEERING; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS; WELDING; WORKING BY LASER BEAM

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.