| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing an austenitic alloy large-diameter pipe, capable of suppressing the formation of cracks on the outer surface of a mother pipe when the mother pipe is produced by boring an ingot. <P>SOLUTION: The method for producing the austenitic alloy large-diameter pipe includes a step of hot boring the ingot consisting of an alloy containing 21-31 mass% of Cr and 43-60 mass% of Ni. Before the step of boring, the ingot is hot-worked in such a manner that a cross section decrease processing ratio R calculated by formula (1): R=(1-S2/S1)×100(%) is 20% or more. In the formula (1), S1 is an ingot cross section area (mm<SP POS="POST">2</SP>) before the hot working, and S2 is an ingot cross section area (mm<SP POS="POST">2</SP>) after hot working. However, when the hot working is performed two times or more, the ratio R depends on formula (2): R=R<SB POS="POST">1</SB>+R<SB POS="POST">2</SB>+, ..., +R<SB POS="POST">n-1</SB>+R<SB POS="POST">n</SB>. <P>COPYRIGHT: (C)2012,JPO&INPIT |
