BLANK TUBE FOR COLD DRAWING AND METHOD FOR PRODUCING THE SAME, AND METHOD FOR PRODUCING COLD DRAWN TUBE

摘要

Disclosed is a blank tube for cold drawing which is used for the production ofa longer-length, small-diameter tube such as a heat-transfer tube for as steamgenerator in nuclear power facilities, in which the blank tube will not causescoringand chattering vibration in a drawing process; and a method for producing theblanktube; as well as a method for producing a cold drawn tube which is obtainedthroughcold drawing of the blank tube. The average surface roughness Ra (ANSI B46.1)ofthe inner surface of blank tube before drawing satisfies the condition: 0.10µm = Ra= 1.00 µm in the case of a blank tube for cold drawing for use in anoil-lubricateddrawing. In particular, the surface roughness Ra satisfies the condition: 0.10µm =Ra = 0.50 µm in the case of a blank tube for use in a high-pressurelubricationdrawing, and which is made of an austenitic alloy for use in a heat-transfertube for asteam generator.