Manufacture of metallic tube having internal and external fins

Abstract

Abstract PURPOSE:To manufacture a metallic tube having internal and external fins and to improve its using performance by inserting a fin stock having radial walls into a tube stock and form-rolling the external peripheral surface. CONSTITUTION:An internal fin stock 12 made by an Al extruded shape in which radial walls 12 are formed integrally on a cylindrical base 12b is inserted into an Al tube stock 11 and the outer peripheral surface of the tube stock 11 is form-rolled by a form-rolling round die 13 to form a spiral fin 3. At this time, the tube stock 11 is deformed by an external pressure inward in the diametrical direction, the internal surface of the tube stock and the tips of the radial walls 12a are brought into close contact and fixed to make an Al tube 1 having internal fins. In this way, the product is completed by one stage and the using performance can be improved when it is used in a heat exchanger.

Inventors

• 👤 Kazuo Taga
• 👤 和夫 多賀

Bibliographic Details