METHOD FOR PRODUCING DOUBLE-WALL TUBE WITH BRAIDED WIRES AT ITS INTERFACE

摘要

Provided is a method for producing a double-wall tube with braided wires at its interface in which the braided wires are interposed between an outer-wall and inner-wall blank tubes and then a drawing process is applied so as for the braided wires to be brought into close contact with the inner surface of the outer-wall tube and the outer surface of the inner-wall tube, the method comprising: polishing the inner surface of the outer-wall blank tube and the outer surface of the inner-wall blank tube so that a surface roughness thereof satisfies Ra<1.0 mum, followed by interposing the braided wires between the outer-wall and inner-wall blank tubes; performing a sinking drawing process so that the difference of the outer diameter of the resulting double-wall tube relative to a die bore diameter is 0.1 mm to 0.3 mm; and subsequently performing heat treatment. The double-wall tube produced is suitable as a heat-transfer tube.