| 摘要 |
PROBLEM TO BE SOLVED: To provide a seamless steel tube having high durability, and a seamless steel tube manufacturing method capable of manufacturing the seamless steel tube with excellent production efficiency and high quality at low cost. SOLUTION: The seamless steel tube 1 is the seamless steel tube 1 which is manufactured through a hot hydrostatic extrusion step (C) for manufacturing a seamless steel tube intermediate body 1a by performing the hot hydrostatic extrusion of at least a cylindrical steel billet 2, and the depth of a continuous flaw formed in an inner circumferential surface and an outer circumferential surface of the steel tube is≤50μm from each surface. The seamless steel tube manufacturing method includes a billet forming step (A), a first heating step (B), the hot hydrostatic extrusion step (C), a second heating step (D), a spreading step (F)/(G), a third heating step (H), and a pickling step (I). COPYRIGHT: (C)2007,JPO&INPIT
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