To provide a method for manufacturing a seamless steel tube by which the seamless steel tube where occurrence of inner surface defects is reduced is manufactured, even when performing piercing rolling by using high Cr-containing steel or martensitic stainless steel.
In this method, the seamless steel tube is manufactured by performing the piercing rolling by using Cr-steel containing, by mass, chromium of ≥9% or the martensitic stainless steel. In this manufacturing method of the seamless steel tube, the piercing rolling is performed by using the billet for making the tubes, in the cross section of a billet for making tube which is obtained by blooming a base stock having a rectangular cross section, the center segregation zone is not parted and the value of the ratio (r/D) of the distance r between the end part in the radial direction of a billet of the center segregation zone on the cross section of the billet and the center of the billet to the diameter D of the billet is ≥0.12.
NAKANISHI TETSUYA
KUBO YASUSHI
| JP2004090088A | 2004-03-25 | |||
| JPH01293909A | 1989-11-27 | |||
| JP2002361384A | 2002-12-17 |