Method for joining heat exchanger tubes with headers.

摘要

In a method for joining a plurality of heat exchanger flat tubes (1) with headers (3) of a heat exchanger: each of the opposite end portions of the flat tubes (1) has a cross section provided with a major axis and a minor axis; opposite major axis side walls (6) of the cross section of each of opposite end portions of each of the flat tubes (1) are obliquely cut off so as to form each of opposite minor axis side walls (5) of the cross section of the end portion of the flat tube into a trapezoidal shape; the end portion of the flat tube is passed through an elliptical hole (4) formed in the header (3); the end portion of the flat tubes (1) thus passed through the header is flared over its entire peripheral wall; the thus flared (5,7 in Fig 2) end portion of the flat tube (1) is then bent (Fig 3) so as to be formed into a bent portion (10,11) of the flat tube (1), which bent portion (10,11) constitutes an essential part of a joint formed between the flat tube (1) and the header (3); and the thus formed joint is dipped into a molten filler metal bath to form brazing portions around the joint.