Blank tube for cold drawing and method for producing the same, and method for producing cold drawn tube

Abstract

A blank tube for cold drawing is used for the production of a longer-length, small-diameter tube such as a heat-transfer tube for steam generation in nuclear power facilities, wherein the blank tube will not cause scoring and chattering vibration in a drawing process. The blank tube is used to produce a cold drawn tube 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 made of an austenitic alloy for use in a heat-transfer tube for a steam generator.

Dependencies are inferred from the claim text.