| 摘要 |
PURPOSE: To manufacture a carbon steel tube superior in the toughness of weld zones. CONSTITUTION: The ends of both sides of a steel sheet 1a are abutted on each other as it is formed into a cylindrical shape; this abutting part is preheated within the range of 300-900 deg.C by induction heating through a feeding device 2; the abutting part is then irradiated with a high energy density beam 5, welded and formed into a carbon steel tube 1. The oxygen content of the welded metal at the abutting part is limited to 300ppm or less. |
