Production of aluminum heat exchanger

TLDR: In this paper, the authors proposed to prevent the buckling of corrugated Al fins owing to the use of the thin-walled fins and to reduce the weight of a heat exchanger by coating an Al alloy brazing filler meal consisting of a limited compsn. p.

Abstract: PURPOSE:To prevent the buckling of corrugated Al fins owing to the use of the thin-walled fins and to reduce the weight of a heat exchanger by coating an Al alloy brazing filler meal consisting of a limited compsn. to the surface of an extruded multi-hole Al tube having a limited m. p., combining the bare fins therewith and heating the assembly thereby brazing the same. CONSTITUTION:The Al alloy brazing filler metal 3 contg., by weight, 6-13% Si, contg. 0.01-1.0% Bi or 0.01-1.0% Bi and =63.5 deg.C m. p. The bare corrugated fins consisting of the Al or Al alloy without being coated with the Al alloy brazing filler metal is then combined therewith and a flux is coated to the joint parts between the tube 1 and the fins 2. The assembly is heated to the melting temp. of the brazing filler metal in an inert gaseous atmosphere and is thus brazed. The reason for limiting the m. p. lies in that hot dipping is made easy. The reason for limiting the compsn. of the brazing filler metal lies in that the hot dipping of the brazing filler metal and the brazing of the tube and the fins are made easy.