| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a seamless steel tube which is excellent in quality of internal surface. SOLUTION: This method is a method for manufacturing the seamless tube by piercing a billet by using a plug on the surface of which a scale film is formed. In the structure of the scale film, the plug on which the generation of the outer layer scale primarily composed of the layer of Fe2 O3 , Fe3 O4 which is formed on the outward of the surface of the base metal of the plug is prevented or a plug from which the outer layer scale primarily composed of the layer of Fe2 O3 , Fe3 O4 is removed is used. Consequently, dropout of the outer layer primarily composed of Fe2 O3 , Fe3 O4 on the way of piercing disappears and the defect on the inside surface and Mannesmann rupture in the center of the billet are effectively suppressed.
|
