METHOD OF MANUFACTURING METAL TUBE

摘要

A cold drawing device (1) comprises a front-stage die (10) and a rear-stage die (11) disposed rearward of the front-stage die (10) and having an outer diameter processing degree of 0.14-1.0% which is defined by expression (1). The front end of a blank tube (50) as a workpiece is squeezed and inserted into the front-stage die (10) and the rear-stage die (11). After the insertion, a plug (20) is inserted into the blank tube (50) from its rear end. After the plug (20) is inserted, the blank tube (50) is drawn. The residual tensile stress in the outer peripheral surface of the manufactured metal tube is reduced by the method above.