| 摘要 |
Disclosed is a blank tube for cold drawing which is used for the production of a longer-length, small-diameter tube such as a heat-transfer tube for as steam generator in nuclear power facilities, in which the blank tube will not cause scoring and chattering vibration in a drawing process; and a method for producing the blank tube; as well as a method for producing a cold drawn tube which is obtained through cold drawing of the blank tube. The average surface roughness Ra (ANSI B46.1) of the inner surface of blank tube before drawing satisfies the condition: 0.10 µm Ra ‰¤ 1.00 µm in the case of a blank tube for cold drawing for use in an oil-lubricated drawing. In particular, the surface roughness Ra satisfies the condition: 0.10 µm ‰¤ Ra ‰¤ 0.50 µm in the case of a blank tube for use in a high-pressure lubrication drawing, and which is made of an austenitic alloy for use in a heat-transfer tube for a steam generator. |
