Method for forming projected part on metallic pipe

Abstract

Abstract PURPOSE:To prevent a drop of a mechanical strength of a projecting part by softening a selected part of a pipe by an electric conduction between electrodes, also reducing a distance of the pipe between the electrodes, and also expanding it by an air pressure. CONSTITUTION:A selected part of a pipe 1 is electrically conducted by providing electrodes 21, 22 on both sides of said part, and by its heating, a projected part forming part is softened. Subsequently, this part is pressed from the side of the electrodes 21, 22 and put into a closed vessel 3 by preventing a decrease of a thickness of the pipe 1. Also, the vessel 3 is made to form a vacuum, this part is expanded by a pressure difference between the outside and the inside, and a projected part of the pipe 1 is formed. According to this method, a decrease of a thickness of the projected part of the pipe 1 is prevented, therefore, a drop of the mechanical strength is prevented.

Inventors

• 👤 Ryoda Sato
• 👤 佐藤　亮拿

Bibliographic Details